Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Dioxines, dioxineachtige- en niet dioxineachtige PCB’s in rode aal uit Nederlandse binnenwateren : resultaten van 2016
    Leeuwen, S.P.J. van; Hoogenboom, L.A.P. ; Kotterman, M.J.J. - \ 2016
    Wageningen : RIKILT Wageningen University & Research (RIKILT-rapport 2016.016) - 33
    palingen - osteichthyes - monitoring - dioxinen - polychloorbifenylen - binnenwateren - besmetting - nederland - eels - osteichthyes - monitoring - dioxins - polychlorinated biphenyls - inland waters - contamination - netherlands
    In 2016 zijn in het kader van het monitoringsprogramma “Monitoring contaminanten ten behoeve van de Nederlandse sportvisserij” 14 zoetwaterlocaties en één zoutwater locatie bemonsterd. Hiervan liggen twaalf locaties binnen het voor aalvisserij gesloten gebied en voor de overige 3 locaties is de aalvisserij toegestaan. Alle locaties zijn in voorgaande jaren al bemonsterd, behalve de Weespertrekvaart, die voor het eerst is bemonsterd in 2016. Dit jaar is voor de bemonstering van grote alen rekening gehouden met het zwaartepunt van de beroepsmatige vangst, waardoor meestal iets grotere aal is bemonsterd (>53 cm) dan in voorgaande jaren (was >45 cm).
    Dioxines, dioxineachtige- en niet dioxineachtige PCB's in rode aal uit Nederlandse binnenwateren 2015
    Kotterman, M.J.J. ; Dam, G. ten; Hoogenboom, L.A.P. ; Leeuwen, Stefan van - \ 2016
    IMARES (Rapport / IMARES C016/16) - 28
    palingen - osteichthyes - monitoring - dioxinen - polychloorbifenylen - binnenwateren - besmetting - nederland - eels - osteichthyes - monitoring - dioxins - polychlorinated biphenyls - inland waters - contamination - netherlands
    In 2015 zijn in het kader van het monitoringsprogramma “Monitoring contaminanten ten behoeve van de Nederlandse sportvisserij” 15 zoetwaterlocaties en één zoutwater locatie in Nederland bemonsterd. Elf locaties liggen binnen het voor aalvisserij gesloten gebied, op de andere vijf locaties is de aalvisserij toegestaan. Van de gevangen rode alen zijn mengmonsters samengesteld voor de lengteklassen 30-40 cm en >45 cm en geanalyseerd op de aanwezigheid van dioxines, dioxineachtige-PCBs (dl-PCB’s) en niet-dioxineachtige PCB’s (ndl-PCB’s).
    Dioxines en PCB's in Chinese wolhandkrab; invloed van grootte en variatie door het seizoen
    Kotterman, M.J.J. ; Vries, P. de; Leeuwen, S.P.J. van; Hoogenboom, L.A.P. - \ 2015
    IMARES Wageningen UR (Rapport / IMARES ) - 43
    krabben (schaaldieren) - decapoda - schaaldieren - dioxinen - polychloorbifenylen - rivieren - meren - nederland - crabs - decapoda - shellfish - dioxins - polychlorinated biphenyls - rivers - lakes - netherlands
    De monitoringsstudies naar de vervuilingsgraad van Chinese Wolhandkrab (WHK) die vanaf 2010 in Nederlandse wateren worden uitgevoerd tonen aan dat de WHK sterk vervuild kan zijn met polychloordibenzo-p-dioxines en -furanen (PCDD/F's, verderop aangeduid als 'dioxines'), met dioxine-achtige polychloorbifenylen (dl-PCB's) en met niet-dioxine achtige PCB’s (ndl-PCB’s). Deze contaminanten bevinden zich vooral in het vlees met hoge vetgehalten, de hepatopancreas (= middendarmklier) en gonaden (= geslachtsklier), vaak aangeduid met het 'bruine vlees' uit het lijf. Het witte spiervlees, uit poten, scharen en ook uit het lichaam, is vetarm en de concentraties dioxines en PCB’s zijn laag. Uit de voorgaande onderzoeken blijkt dat er een sterk geografische invloed is op de concentraties contaminanten in WHK; bijvoorbeeld WHK gevangen in de grote rivieren zijn sterker vervuild dan WHK uit het IJsselmeer. Over een eventuele tijdsafhankelijke variatie waardoor bijvoorbeeld gedurende het trekseizoen de concentraties contaminanten in de WHK sterk wisselen op een bepaalde locatie, is nog niets bekend. Er is wel reden om dat aan te nemen. WHK leggen in het trekseizoen grote afstanden af. De kans is daarom reëel dat de WHK die in een bepaald gebied worden gevangen van verschillende locaties afkomstig zijn, waardoor de concentraties contaminanten tussen individuele WHK kunnen verschillen.
    Rapportage dioxines, dioxineachtige- en niet dioxineachtige PCB's in rode aal uit Nederlandse binnenwateren
    Leeuwen, S.P.J. van; Dam, G. ten; Hoogenboom, L.A.P. ; Kotterman, M.J.J. - \ 2015
    Wageningen : RIKILT Wageningen UR (RIKILT rapportage dioxines 2015 ) - 19
    vissen - zoet water - ecotoxicologie - dioxinen - polycyclische koolwaterstoffen - european eels - monitoring - ijsselmeer - waterwegen - maas - rijn - waal - volkerak-zoommeer - ijssel - hollandsch diep - voedselveiligheid - fishes - fresh water - ecotoxicology - dioxins - polycyclic hydrocarbons - european eels - monitoring - lake ijssel - waterways - river meuse - river rhine - river waal - volkerak-zoommeer - river ijssel - hollandsch diep - food safety
    In 2014 zijn in het kader van het monitoringsprogramma "Monitoring contaminanten ten behoeve van de Nederlandse sportvisserij" 17 zoetwaterlocaties in Nederland bemonsterd. Van de gevangen rode alen zijn mengmonsters samengesteld voor de lengteklassen 30-40 cm en >45 cm en geanalyseerd op de aanwezigheid van dioxines, dioxineachtige- en nietdioxineachtige PCB's. De gevonden gehaltes sluiten goed aan bij de resultaten van 2013. Mengmonsters van kleine alen zijn onderzocht op 12 locaties en in 3 gevallen werden één of meerdere normen overschreden. De mengmonsters van grotere alen (>45 cm) voldeden op 9 van de onderzochte locaties niet aan één of meerdere normen. Naast aal uit de gesloten gebieden betrof dat ook aal uit het open gebied Amsterdam-Rijnkanaal bij Diemen. Per 1-1- 2015 behoort het Amsterdam-Rijnkanaal ook tot de gesloten gebieden. Anderzijds waren er ook locaties binnen de gesloten gebieden waar de mengmonsters aal wel voldeden aan de normen. Dit betrof beide locaties van het Volkerak.
    Carryover of cadmium from feed in growing pigs
    Hoogenboom, L.A.P. ; Hattink, J. ; Polanen, A. van; Oostrom, J.J. van; Verbunt, J.T. ; Traag, W.A. ; Kan, K.A. ; Eijkeren, J.C.H. ; Boeck, G. de; Zeilmaker, M.J. - \ 2015
    Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 32 (2015)1. - ISSN 1944-0049 - p. 68 - 79.
    cd-saturation method - sludge-amended soil - metallothionein - tissues - growth - swine - accumulation - dioxins - protein - cortex
    Growing male pigs were exposed to cadmium (Cd) at levels around 1 and 10 mg kg–1 feed for up to 12 weeks, administered as CdCl2 or Cd-cysteine (CdCys). Pigs exposed to 10 mg kg–1 showed decreased growth during the last 3 weeks. Liver and kidney concentrations of Cd continuously increased over the entire 12-week exposure, exceeding the European Union limits of 1.0 mg kg–1 (kidney) and 0.5 mg kg–1 (liver) within 3 weeks at the feed level of 10 mg kg–1. A switch to clean feed after 3 weeks for 5 or 9 weeks resulted in steadily decreased levels in kidney and liver, which could be completely attributed to organ growth. At the lower feed level, the level in kidney exceeded the limit almost twofold after 12 weeks, but not after 3 weeks. Liver levels remained below the limit. Metallothionein (MT) levels in livers showed a steady decrease in both untreated and treated animals over time. In kidney such a decrease was only observed in control animals, whereas in the highest-dosed animals the MT concentrations steadily increased. The observed carryover of Cd from feed to liver and kidney was modelled by means of a simple transfer model relating levels in feed via MT levels to accumulation of Cd. Using this model, it was shown that the exposure period of growing pigs to feed containing the European Union limit of 0.5 mg kg–1 feed should be less than 12 weeks in order to prevent Cd levels in the kidneys to exceed the European Union limit.
    Long term plant biomonitoring in the vicinity of waste incinerators in The Netherlands
    Dijk, C.J. van; Doorn, W. van; Alfen, A.J. van - \ 2015
    Chemosphere 122 (2015). - ISSN 0045-6535 - p. 45 - 51.
    refuse incinerator - heavy-metals - dioxins - health - bioindicators - cadmium - lead
    Since the mid-nineties new waste incineration plants have come into operation in the Netherlands. Burning of waste can result in the emission of potentially toxic compounds. Although the incineration plants must comply with strict conditions concerning emission control, public concern on the possible impact on human health and the environment still exists. Multiple year (2004–2013) biomonitoring programs were set up around three waste incinerators for early detection of possible effects of stack emissions on the quality of crops and agricultural products. The results showed that the emissions did not affect the quality of crops and cow milk. Concentrations of heavy metals, PAHs and dioxins/PCBs were generally similar to background levels and did not exceed standards for maximum allowable concentrations in foodstuffs (e.g. vegetables and cow milk). Some exceedances of the fluoride standard for cattle feed were found almost every year in the maximum deposition areas of two incinerators. Biomonitoring with leafy vegetables can be used to monitor the real impact of these emissions on agricultural crops and to communicate with all stakeholders.
    Dioxines en PCB's in Chinese wolhandkrab
    Kotterman, M.J.J. ; Leeuwen, S.P.J. van; Hoogenboom, L.A.P. - \ 2014
    IJmuiden : IMARES (Rapport / IMARES C120/14) - 36
    krabben (schaaldieren) - dioxinen - polychloorbifenylen - besmetting - toxinen - zeevisserij - crabs - dioxins - polychlorinated biphenyls - contamination - toxins - marine fisheries
    Dioxines en PCB's in rivierkreeften uit Zuid-Holland en Utrecht
    Leeuwen, S.P.J. van; Kotterman, M.J.J. ; Hoogenboom, L.A.P. ; Soest, D.M. van - \ 2014
    Wageningen : RIKILT Wageningen UR (Rapport / RIKILT 2014.005) - 15
    rivierkreeft - dioxinen - polychloorbifenylen - aquatische ecologie - voedselveiligheid - waterbeheer - natuurbeheer - utrecht - zuid-holland - crayfish - dioxins - polychlorinated biphenyls - aquatic ecology - food safety - water management - nature management - utrecht - zuid-holland
    Drie mengmonsters rivierkreeft, afkomstig van drie watersystemen in Zuid-Holland en Utrecht zijn onderzocht op aanwezigheid van dioxines en polychloorbifenylen (PCB's).
    Gezocht : chemische sporen van palingconsumptie
    Ramaker, R. ; Dungen, M.W. van den - \ 2014
    Resource: nieuwssite voor studenten en medewerkers van Wageningen UR 9 (2014)9. - ISSN 1389-7756 - p. 8 - 8.
    palingen - visconsumptie - voedselveiligheid - verontreinigd water - epigenetica - dioxinen - eels - fish consumption - food safety - polluted water - epigenetics - dioxins
    Onderzoeker wil honderd palingvissers voor onderzoek. Frequente palingeters geven mogelijk informatie over effect vervuiling.
    Dioxines en PCB's in eieren van particuliere kippenhouders
    RIKILT, - \ 2014
    Wageningen : RIKILT Wageningen UR (RIKILT-rapport 2014.012) - 25
    eieren - dioxinen - voedselveiligheid - pluimveehouderij - eggs - dioxins - food safety - poultry farming
    Dit rapport geeft een eerste beeld van gehaltes in eieren van particuliere kippenhouders en doet een aantal aanbevelingen om de inname van dioxines en dioxineachtige PCB’s door leghennen te reduceren.
    Consumptie van Chinese wolhandkrab in Nederland
    Leeuwen, S.P.J. van; Stouten, P. ; Zaalmink, W. ; Hoogenboom, L.A.P. - \ 2013
    Wageningen : RIKILT Wageningen UR (RIKILT-rapport 2013.018) - 43
    krabben (schaaldieren) - geïntroduceerde soorten - visconsumptie - voedselconsumptie - consumptiepatronen - voedselveiligheid - dioxinen - krabsvlees - polychloorbifenylen - crabs - introduced species - fish consumption - food consumption - consumption patterns - food safety - dioxins - crab meat - polychlorinated biphenyls
    Deze inventarisatie beschrijft de consumptiegebruiken van in Nederland woonachtige personen. Daarnaast zijn de handelsstromen van de wolhandkrab in Nederland en vanuit Nederland onderzocht.
    Evaluation for salt stress tolerance of pepper genotypes to be used as rootstocks
    Penella, C. ; Nebauer, S.G. ; Lopéz-Galarza, S. ; SanBautista, A. ; Gorbe, E. ; Calatayud, A. - \ 2013
    Journal of Food, Agriculture & Environment 11 (2013)3&4. - ISSN 1459-0255 - p. 1101 - 1107.
    precautionary principle - basel convention - governance - negotiations - shellfish - malaysia - dioxins - fish
    Salinity is a major environmental constraint on crop productivity and grafting can be a sustainable strategy to enhance plant tolerance under adverse growth conditions. Screening different graft combinations under field conditions can be a slow and expensive processes. In this study, plants of 18 genotypes of Capsicum spp. were evaluated during 5 months to select salt tolerant plants to be used as rootstocks in greenhouse under controlled conditions. Their net photosynthetic rate was used as a rapid and sensitive methodology for screening their tolerance to salt stress conditions. The germination potential of some genotypes was also tested under different salinity conditions to see if it would be useful to accelerate the screening process. According to photosynthesis rate, the commercial rootstock ‘Tresor’ and the genotypes ‘Serrano’ (C. annuum), ‘ECU-973’ (C. chinense) and ‘BOL-58’ (C. baccatum) were the most tolerant during this period. Nevertheless, the evaluation of pepper genotypes for salinity tolerance based on the germination performance and chlorophyll fluorescence parameter Fv/Fm ratio were not good indicators of the sensitivity along plant ontogeny. Finally, the selected genotypes as salt-tolerant were validated under field conditions as rootstocks of two interesting pepper cultivars, concluding that using the rootstocks selected by the net photosynthetic rate improved the salt tolerance of the scion in terms of marketable yield and fruit quality.
    Proficiency test for dioxins and dioxin-like PCBs in fats
    Elbers, I.J.W. ; Traag, W.A. - \ 2013
    Wageningen : Rikilt - Institute of Food Safety (RIKILT-report 2013.017) - 113
    diervoeding - veevoeder - plantaardige vetten - dioxinen - polychloorbifenylen - voederveiligheid - tests - verontreinigende stoffen - toxische stoffen - voersamenstelling - animal nutrition - fodder - plant fats - dioxins - polychlorinated biphenyls - feed safety - tests - pollutants - toxic substances - feed formulation
    The test provides an evaluation of the methods applied for quantification of dioxins and dioxin-like PCBs in fat by the laboratories. The proficiency test was organised according to ISO 17043. For this test, four samples were prepared: - sunflower oil spiked with dioxins and PCBs; - sunflower oil mixed with contaminated fish oil; - sunflower oil mixed with contaminated chicken fat and spiked with 2,3,7,8-PCDF; - sunflower oil mixed with contaminated chicken fat and spiked with non-dioxin like PCBs.
    Verontreiniging Nederlandse schieraal 2009-2010 : onderzoek naar dioxines, PCB’s, organochloorverbindingen en gebromeerde vlamvertragers (PBDE’s) in schieraal uit Friese meren en het rivierengebied
    Lee, M.K. van der; Leeuwen, S.P.J. van; Nieuwenhuizen-Hoek, M. van; Kotterman, M.J.J. ; Hoogenboom, L.A.P. - \ 2013
    Wageningen [etc.] : RIKILT [etc.] (RIKILT-report 2013.004) - 29
    palingen - european eels - dioxinen - ecotoxicologie - binnenwateren - meren - friesland - biesbosch - eels - european eels - dioxins - ecotoxicology - inland waters - lakes - friesland - biesbosch
    Deze studie laat zien dat schieraal uit het rivierengebied in hoge mate verontreinigd is met een aantal contaminanten en de norm voor dioxines en dioxineachtige PCB's sterk overschrijdt. Schieraal uit de Friese meren is veel minder gecontamineerd en voldoet wel aan de normen.
    Grond met gerelateerde voedselincidenten met dioxines en PCB's
    Hoogenboom, L.A.P. ; Traag, W.A. - \ 2013
    Wageningen : Rikilt - Institute of Food Safety (Rapport / RIKILT, Institute of Food Safety 2013.012) - 33
    bodemverontreiniging - ecotoxicologie - dioxinen - polychloorbifenylen - veevoeder - voederveiligheid - verontreinigde grond - voedselveiligheid - inventarisaties - schapenhouderij - pluimveehouderij - hennen - soil pollution - ecotoxicology - dioxins - polychlorinated biphenyls - fodder - feed safety - contaminated soil - food safety - inventories - sheep farming - poultry farming - hens
    Dioxines en PCB's blijven de agenda van de contaminanten beheersen. Waar het in eerste instantie een probleem van vuilverbranding was, later traden voergerelateerde incidenten met andere bronnen op de voorgrond. Nu deze (voergerelateerde) bronnen onder controle zijn, lijkt het milieu een grotere rol te spelen als bron voor dioxines en PCB's. Anders dan bij voeders zijn er voor grond op agrarische bedrijven geen duidelijke normen, die moeten voorkómen dat dierlijke producten besmet raken. Het is duidelijk dat dieren, die grazen of scharrelen, een bepaalde hoeveelheid grond kunnen opnemen. Bij koeien wordt uitgegaan van 4% van de droge stof. Bij schapen, die het gehele jaar buiten zijn, zou dat nog wel hoger kunnen uitvallen. Dit rapport geeft een literatuuroverzicht van bekende onderzoeksresultaten.
    Dioxines en PCB's in rode aal uit Nederlandse binnenwateren: resultaten tussen 2006 en 2012
    Leeuwen, S.P.J. van; Kotterman, M.J.J. ; Hoek-van Nieuwenhuizen, M. van; Lee, M.K. van der; Hoogenboom, L.A.P. - \ 2013
    Wageningen : RIKILT Wageningen UR (Rapport / RIKILT 2013.010) - 73
    palingen - waterverontreiniging - ecotoxicologie - dioxinen - meren - binnenwateren - rivierengebied - ijsselmeer - friesland - eels - water pollution - ecotoxicology - dioxins - lakes - inland waters - rivierengebied - lake ijssel - friesland
    Aal (ook bekend als Europese paling - Anguilla) wordt beroepsmatig bevist en op de markt gebracht. Contaminanten zoals dioxines en polychloorbifenylen (PCB's) worden aangetoond in aal uit de Nederlandse wateren. Normoverschrijdende dioxine- en PCB-gehalten in rode aal uit de grote rivieren en het benedenrivierengebied hebben in 2011 geleid tot sluiting van deze gebieden voor de aalvangst. In schonere wateren zoals het IJsselmeer en de Friese meren is aalvangst wel toegestaan.
    De invloed van de waterbodem op de waterkwaliteitsdoelen van het Noordzeekanaal : met specifieke aandacht voor de dioxineproblematiek
    Postma, J. ; Rozemeijer, M.J.C. ; Schobben, J.H.M. - \ 2013
    IJmuiden : IMARES (Rapport / IMARES Wageningen UR C092/13) - 210
    waterwegen - waterbodems - sedimentatie - dioxinen - bodemverontreiniging - ecotoxicologie - noord-holland - waterways - water bottoms - sedimentation - dioxins - soil pollution - ecotoxicology - noord-holland
    De waterbodem in het Noordzeekanaal is in het verleden ernstig verontreinigd geraakt met dioxines, onder andere door een explosie van een reactorvat bij Philips Duphar in 1963 bij de Jan van Riebeeckhaven. Een aanvankelijk geplande waterbodemsanering is in 2009 vanwege een bezuinigingstaakstelling komen te vervallen. Daaropvolgend is Rijkswaterstaat West-Nederland Noord in 2010 als beheermaatregel begonnen met monitoring van het gebied om na te gaan in hoeverre er verspreiding optreedt van dioxines naar de omliggende waterbodem en biota. De verkregen data zijn aangevuld met andere beschikbare monitoringgegevens en verwerkt tot een totaaloverzicht van het Noordzeekanaal van de waterbodem- en zwevend-stofkwaliteit en van bioaccumulatie van verontreinigingen.
    Dioxines en PCB's in Chinese wolhandkrab
    Leeuwen, S.P.J. van; Kotterman, M.J.J. ; Lee, M.K. van der; Hoogenboom, L.A.P. - \ 2013
    Wageningen : Rikilt - Institute of Food Safety (Report / RIKILT, Institute of Food Safety 2013.005) - 21
    krabben (schaaldieren) - dioxinen - polychloorbifenylen - ecotoxicologie - zware metalen - binnenwateren - crabs - dioxins - polychlorinated biphenyls - ecotoxicology - heavy metals - inland waters
    Onderzoek naar contaminanten in Chinese wolhandkrab.
    Levels and trends of dioxins and dioxin-like PCBs in feed : levels and trends of dioxins and dioxin-like PCBs in feed in the Netherlands during the last decade (2001-2011)
    Schoss, S. ; Adamse, P. ; Immerzeel, J. ; Traag, W.A. ; Egmond, H.J. van; Jong, J. de; Hoogenboom, L.A.P. - \ 2012
    Wageningen : RIKILT Wageningen UR (Report / RIKILT 2012.012) - 129
    polychloorbifenylen - dioxinen - voer van dierlijke oorsprong - voederveiligheid - voedselveiligheid - polychlorinated biphenyls - dioxins - feed of animal origin - feed safety - food safety
    Trend analysis on monitoring data could be a suitable method to identify feed commodities with higher dioxin or DL-PCB concentrations, thus contributing to risk-based monitoring. The aim of the present study was to obtain insight into background levels of dioxins and dioxin-like PCBs (DL-PCBs) in feed and potential trends therein.
    Schatting percentage schone wolhandkrab in de gesloten gebieden
    Kotterman, M.J.J. ; Lee, M.K. van der; Bierman, S.M. - \ 2012
    IJmuiden : IMARES (Rapport / IMARES Wageningen UR C043/12) - 31
    krabben (schaaldieren) - verontreiniging - polychloorbifenylen - dioxinen - besmetting - voedselveiligheid - nederland - crabs - pollution - polychlorinated biphenyls - dioxins - contamination - food safety - netherlands
    In dit rapport wordt het percentage geschat van de wolhandkrabvangst van beroepsvissers in het gesloten gebied die onder de waarde van 8 pg/g ligt en wel voor consumptie geschikt zou zijn. Het ministerie van EL&I wil daarbij dat voor het gehele gesloten gebied één percentage van wolhandkrab onder de 8 pg som-TEQ/g wordt berekend.
    Contaminanten in schubvis : onderzoek naar dioxines, PCB's en zware metalen in shubvis
    Lee, M.K. van der; Leeuwen, S.P.J. van; Nieuwenhuizen-Hoek, M. van; Kotterman, M.J.J. ; Hoogenboom, L.A.P. - \ 2012
    Wageningen [etc.] : RIKILT [etc.] (Rapport / RIKILT - Instituut voor Voedselveiligheid 2012.011) - 16
    vissen - dioxinen - zware metalen - binnenwateren - bioaccumulatie - waterverontreiniging - aquatische ecologie - monitoring - fishes - dioxins - heavy metals - inland waters - bioaccumulation - water pollution - aquatic ecology - monitoring
    Voor het in kaart brengen van de vervuiling van schubvis met dioxines, dioxineachtige PCB's en niet dioxineachtige PCB's en zware metalen zijn op 10 locaties in Nederland brasem, voorn en snoekbaars bemonsterd en geanalyseerd. De resultaten laten zien dat de gehalten dioxines voor alle soorten onder de geldende Europese norm liggen. Hetzelfde geldt voor de gehalten aan zware metalen. Brasem gevangen in de Nieuwe Maas bij Pernis was het meest gecontamineerd en benadert de norm
    Contaminanten in Chinese wolhandkrab : onderzoek naar dioxines, PCB's en zware metalen in Chinese wolhandkrab
    Lee, M.K. van der; Leeuwen, S.P.J. van; Kotterman, M.J.J. ; Hoogenboom, L.A.P. - \ 2012
    Wageningen : RIKILT (Rapport / RIKILT 2012.010) - 25
    krabben (schaaldieren) - dioxinen - polychloorbifenylen - zware metalen - waterverontreiniging - binnenwateren - ecotoxicologie - analytische methoden - nederland - crabs - dioxins - polychlorinated biphenyls - heavy metals - water pollution - inland waters - ecotoxicology - analytical methods - netherlands
    Dit onderzoek heeft tot doel om (a) in beeld te brengen wat de mate van vervuiling is van de Chinese wolhandkrab (WHK) uit diverse Nederlandse oppervlaktewateren (met name locaties die in de voor visserij gesloten gebieden liggen) en (b) hoe de contaminanten verdeeld zijn over enerzijds het vlees in de poten en anderzijds het vlees en de organen in het lijf van de WHK. Naast bovenstaande doelstellingen wordt er in dit rapport ook rekenkundig een schatting gemaakt van de contaminantgehaltes op basis van de gehele krab (vlees uit poten en lijf tezamen).
    Levels of PCDD/Fs, PCBs and PBDEs in butter from Turkey and estimated dietary intake from dairy products
    Ucar, Y. ; Traag, W.A. ; Immerzeel, J. ; Kraats, C. van de; Lee, M.K. van der; Hoogenboom, L.A.P. ; Weg, G. van der; Cakirogullari, G.C. ; Oymael, B. ; Kilic, D. - \ 2011
    Food Additives & Contaminants Part B-Surveillance 4 (2011)2. - ISSN 1939-3210 - p. 141 - 151.
    polybrominated diphenyl ethers - human exposure - market-basket - dioxins - netherlands - foodstuffs - food - sea - fat
    Polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs), dioxin-like and non-dioxin-like (indicator) polychlorinated biphenyls (PCBs) and polybrominated diphenylethers (PBDEs) were monitored in butterfat obtained from 18 different areas in Turkey, both rural and industrial. The results obtained both at RIKILT in the Netherlands and in a food control laboratory in Turkey for PCDD/Fs and PCBs were in good agreement. The sum of PCDD/Fs+dl-PCBs, total indicator PCBs and PBDEs were in the range 0.26-3.82 pg TEQ g-1 fat, 0.20-3.04 ng g-1 fat and 0.18-5.00 ng g-1 fat, respectively. Despite the very low levels measured, slightly elevated PCDD/F and PCB levels were found in Izmir-Aliaa, Kocaeli, Denizli, and Zonguldak. The only result exceeding the EU action level was the dl-PCB concentration in Izmir-Aliaa. Ratios of PCDD/Fs and PCBs indicate that contamination in the elevated areas originated from different sources. High BDE 209 levels were detected in Mersin and Bursa. For the 18 regions analysed, the average total daily intake of total TEQ (dioxins and dl-PCBs) from butterfat was 0.09 pg TEQ(1998) (0.08 pg TEQ(2005)) kg-1 body weight, while those for indicator PCBs and PBDEs were 58.8 and 35.1 pg kg-1 body weight, respectively. The average total daily intake from dairy products were 0.26 pg TEQ(1998) (0.20 pg TEQ(2005)), 183 and 103 pg kg-1 body weight, respectively.
    Dioxin monitoring in fats oils for the feed industry
    Asselt, E.D. van; Sterrenburg, P. - \ 2011
    Wageningen : Rikilt - Institute of Food Safety (Report / RIKILT, Institute of Food Safety 2011.004) - 37
    dioxinen - monitoring - vetten - oliën - veevoederindustrie - analytische scheikunde - productieprocessen - voedselveiligheid - dioxins - monitoring - fats - oils - feed industry - analytical chemistry - production processes - food safety
    The aim of the present project was to determine the most critical steps in the production of fats and oils. First, production processes of vegetables oils, animal fat, fish oil, biodiesel and fat blending were studied and experts from the industry as well as in-house dioxin experts were consulted to identify the most critical steps. Then, monitoring data for vegetable oil, animal fat and fish oil were analysed to determine which products have an increased risk of dioxin contamination.
    Gehaltes aan dioxines en dioxineachtige PCB's (totaal-TEQ) in paling en wolhandkrab uit Nederlands zoetwater
    Kotterman, M.J.J. ; Lee, M. van der - \ 2011
    IJmuiden : IMARES (Rapport / IMARES Wageningen UR C011/11) - 37
    palingen - krabben (schaaldieren) - dioxinen - polychloorbifenylen - indicatoren - aquatische toxicologie - normen - voedselveiligheid - monitoring - eels - crabs - dioxins - polychlorinated biphenyls - indicators - aquatic toxicology - standards - food safety - monitoring
    Het ministerie van EL&I heeft het voornemen om maatregelen te nemen voor die gebieden waar vis wordt gevangen die niet voldoet aan de Europese productnormen voor dioxines en PCB's. Daarom zijn in opdracht van EL&I de data betreffende dioxines en dioxineachtige PCB’s (uitgedrukt in totaal-TEQ, de som van dioxineachtige toxiciteit veroorzaakt door dioxines en dioxineachtige PCB's) in aal en wolhandkrab uit het Nederlandse zoete water geëvalueerd. Het betreft aaldata die in de afgelopen vijf jaar zijn gemeten door RIKILT, ondersteund door PCB analyseresultaten en historische data van IMARES. Voor wolhandkrab is in 2010 een beperkt monitoringonderzoek uitgevoerd.
    Evaluatie van effecten van een visserij op pootaal in het rivierengebied op de ontwikkeling van de bovenstroomse aal populatie en de aaldoelstellingen
    Bierman, S.M. ; Graaf, M. de - \ 2011
    IJmuiden : IMARES (Rapport / IMARES Wageningen UR C006/11) - 20
    palingen - european eels - visbestand - visserij - binnenwateren - ecotoxicologie - dioxinen - polychloorbifenylen - voedselveiligheid - eels - european eels - fishery resources - fisheries - inland waters - ecotoxicology - dioxins - polychlorinated biphenyls - food safety
    Aal uit het gebied van de benedenrivieren bevat hoge gehalten aan contaminanten, waaronder dioxine en dioxineachtige pcb's, zodanig veel dat deze aal op basis van de warenwet niet in de markt mag worden afgezet. Aalvissers uit het benedenrivierengebied hebben het idee om op pootaal (aal met lengten kleiner dan de geldende minimum aanlandingsmaat) te gaan vissen, en deze aal als commercieel product te verkopen aan andere aalvissers zodat deze kan worden uitgezet in schone wateren voor verdere opgroei tot een verkoopbaar product wat wel aan de voedselveiligheidsnormen voldoet.
    Homogeniteit als uitgangspunt voor monsternamestrategie : monsternamestrategie van partijen diervoedergrondstoffen in relatie tot de heterogeniteit voor controle op mycotoxines en dioxinen
    Berendsen, B.J.A. ; Jong, J. de - \ 2010
    Wageningen : RIKILT, Instituut voor Voedselveiligheid (Rapport / RIKILT 2010.014) - 46
    voer - ingrediënten - voedselanalyse - monsters - representatieve monstername - mycotoxinen - dioxinen - voedselveiligheid - feeds - ingredients - food analysis - samples - representative sampling - mycotoxins - dioxins - food safety
    In dit rapport wordt de monsternameproblematiek toegespitst op de analyse van mycotoxines en dioxinen in diervoedergrondstoffen. Eerst wordt in hoofdstuk 2 de Europese regelgeving betreffende monstername van diervoeders uiteengezet. In hoofdstuk 3 wordt de homogeniteit gedefinieerd en in hoofdstuk 4 wordt ingegaan op de onzekerheid in het eindresultaat. In hoofdstuk 5 worden relevante parameters voor beperking van de monsternameonzekerheid geïdentificeerd en worden methodes ter bepaling van de monsternameonzekerheid bediscussieerd. Op basis hiervan worden in hoofdstuk 6 conclusies getrokken en aanbevelingen gedaan voor vervolgonderzoek en een praktisch toepasbare strategie voor de controle van diervoedergrondstoffen op mycotoxines en dioxinen die moet leiden tot een betere interpretatie van analyseresultaten.
    Onderzoek naar de effectiviteit van bodembewerking op het gehalte van dioxines en dioxine-achtige PCB's in het Rijnmondgebied
    Traag, W.A. ; Zeilmaker, M.J. ; Eijkeren, J.C.H. van; Hoogenboom, L.A.P. - \ 2010
    Wageningen : RIKILT, Instituut voor Voedselveiligheid (Rapport / RIKILT 2010.012) - 25
    bodemkwaliteit - bodemverontreiniging - dioxinen - polychloorbifenylen - grondbewerking - soil quality - soil pollution - dioxins - polychlorinated biphenyls - tillage
    In het verleden is (met name in het voorjaar) in koemelk in het Rijnmondgebied een relatief hoge concentratie dioxines en dioxine-achtige PCB's aangetroffen. Vermindering van de inname van dioxines en dioxine-achtige PCB's via de bodem kan bereikt worden door de bovenste bodemlaag van 0-10 cm d.m.v. grondomwerking te vermengen met de eronder liggende laag die veel minder verontreinigd is. Om de effectiviteit van zo’n bewerking vast te stellen zijn op een perceel waar recent (najaar 2007) een dergelijke omwerking is uitgevoerd grondmonsters genomen en op dioxines en dioxine-achtige PCB's onderzocht. Ter controle zijn grondmonsters genomen op een naastliggend perceel waarvan met zekerheid bekend is dat de grond de afgelopen decennia niet is omgewerkt.
    Compliance of feed limits, does not mean compliance of food limits
    Raamsdonk, L.W.D. van; Eijkeren, J.C.H. van; Meijer, G.A.L. ; Rennen, M. ; Zeilmaker, M.J. ; Hoogenboom, L.A.P. ; Mengelers, M.J.B. - \ 2009
    Biotechnology, Agronomy, Society and Enviroment 13 (2009)S. - ISSN 1370-6233 - p. 51 - 57.
    dioxins - risk - soil
    The carry-over of contaminants from feed to animal food products is an important aspect of the animal production chain. For a proper containment, limits for feed as well food products are fixed for a series of chemicals, e.g. dioxins and dioxin-like PCBs, lead, cadmium, some chlorinated pesticides, and aflatoxin B1 (and its metabolite M1 in milk). The relationship between feed and food limits is an important issue. An ideal goal is to assure that compliance to a feed limits automatically results in compliance to food limits. In order to collect information about this relationship, several simulation models and a large database on transfer factors have been developed. An optimal choice between either a model or an application of data from the Transfer Database is based on both the knowledge level, and on the circumstances of the specific situation. To reach and validate such an optimal choice an Expert System Carry-Over is currently in development, containing four different modules: 1) the different calculation models and the Transfer Database, 2) a decision tree for choosing the optimal strategy, 3) data tables indicating knowledge levels of compound/animal/product parameters, and 4) supporting databases containing information on consumption and composition of daily diets, animal parameters, and amounts of (daily) production. Calculations indicate that for dioxins compliance to feed levels does not necessarily mean that food limits are complied as well. Besides an estimation of the compliance to limits, the expert system is a tool for feed related risk assessments, and for planning of future research. Keywords. Feed safety, animal health, carry-over, simulation models, decision support system, chemical contaminants, dioxin, aflatoxin, cadmium, nickel
    Verontreiniging rode aal Nederlandse binnenwateren : monitoring voor sportvisserij 2004-2008
    Lee, M.K. van der; Traag, W.A. ; Hoek, M. van der; Kotterman, M.J.J. ; Hoogenboom, L.A.P. - \ 2009
    Wageningen : RIKILT (Rapport / RIKILT 2009.011)
    european eels - ecotoxicologie - waterverontreiniging - sportvissen - dioxinen - binnenwateren - visvangsten - european eels - ecotoxicology - water pollution - game fishes - dioxins - inland waters - fish catches
    Rode aal, ook bekend als Europese paling (Anguilla anguilla) werd gebruikt als bioindicator binnen het monitoringsprogramma 'verontreiniging in vis uit de Nederlandse binnenwateren'. In de afgelopen 5 jaar zijn 65 mengmonsters rode aal met een lengte van 30-40 cm onderzocht op de aanwezigheid van dioxines en dioxineachtige PCB's. Deze alen zijn afkomstig van 38 locaties uit de nederlandse binnenwateren. In 54% van de onderzochte alen zijn normoverschrijdende gehaltes dioxines en / of dioxine-achtige PCB's aangetoond. Aal uit de Roer, Dordsche Biesbosch, Amer, Hollands Diep en verschillende locaties in de grote rivieren is sterk vervuild. In 2007 werd specifiek gekeken naar 40 individuele schieralen gevangen in het Haringvliet. In dit stadium trekt deze relatief oude aal naar zee om zich voort te planten in de Sagossozee.
    National Reference Laboratory dioxins, PCB's, polycyclic aromatic hydrocarbons, heavy metals, pesticides and mycotoxins in feed and animal products : annual report 2007
    Traag, W.A. ; Mol, J.G.J. ; Hoogenboom, L.A.P. - \ 2008
    Wageningen : RIKILT (Report / RIKILT, Institute of Food Safety 2008.011) - 36
    analytische methoden - referentienormen - dioxinen - zware metalen - pesticiden - mycotoxinen - kwaliteitscontroles - polycyclische aromatische koolwaterstoffen - analytische scheikunde - analytical methods - reference standards - dioxins - heavy metals - pesticides - mycotoxins - quality controls - polycyclic aromatic hydrocarbons - analytical chemistry
    Gebromeerde vlamvertragers en broomdioxines in Choline Chloride
    Egmond, H.J. van; Traag, W.A. ; Hoogenboom, L.A.P. - \ 2008
    Wageningen : RIKILT (Rapport / RIKILT 2008.106) - 11
    vuurvertragingsmiddelen - dioxinen - voedertoevoegingen - voedselbesmetting - broomhoudende vlamvertragers - fire retardants - dioxins - feed additives - food contamination - brominated flame retardants
    Sinds begin 2008 worden in het Nationaal Plan Diervoeder Choline Chloride monsters (= diervoeder additief) gevonden waarbij de DR CALUX screenings-assay een sterk verdacht signaal geeft, maar bij de GC-HRMS geen dioxines en dl-PCB's worden gevonden. Dit rapport beschrijft de resultaten van nader onderzoek in twee Choline Chloride monsters (één met lage DR CALUX (ca. 2-3 ng BEQ/kg) en één met hoge DR CALUX respons (4-5 ng BEQ/kg) op gebromeerde vlamvertragers en broomdioxines
    Prolonged ELS test with the marine flatfish sole (Solea solea) shows delayed toxic effects of previous exposure to PCB 126
    Foekema, E.M. ; Deerenberg, C.M. ; Murk, A.J. - \ 2008
    Aquatic Toxicology 90 (2008)3. - ISSN 0166-445X - p. 197 - 203.
    tong (vis) - solea - polychloorbifenylen - marien milieu - dioxinen - verontreinigingen - levenscyclus - larven - ecotoxicologie - aquatische ecosystemen - visstand - dover soles - solea - polychlorinated biphenyls - marine environment - dioxins - impurities - life cycle - larvae - ecotoxicology - aquatic ecosystems - fish stocks - polyhalogenated aromatic-hydrocarbons - flounder platichthys-flesus - dibenzo-p-dioxins - in-vitro bioassay - polychlorinated-biphenyls - dr-calux(r) bioassay - equivalency factors - sediment extracts - life stages - fish
    The effect of the dioxin-like PCB 126 (3,3¿,4,4¿,5-pentachlorobiphenyl) on the early development of the marine flatfish sole (Solea solea) was tested in a newly developed early life stage (ELS) test that includes the metamorphosis of the symmetric larvae into an asymmetrical flatfish. Early life stages of sole were exposed to a concentration series of PCB 126 in seawater until 4, 8, 10 and 15 days post fertilisation (dpf). Subsequently the development of the larvae was registered under further unexposed conditions. The LC50s at the start of the free-feeding stage (12 dpf) ranged between 39 and 83 ng PCB 126/l depending on exposure duration. After the fish had completed the metamorphosis, the LC50 values ranged between 1.7 and 3.7 ng PCB 126/l for the groups exposed for 4, 8 and 10 dpf, respectively. Thus exposure for only 4 days, covering only the egg stage, was sufficient to cause adverse effects during a critical developmental phase two weeks later. The internal dosages of these larvae, determined by means of an in vitro gene reporter assay as dioxin-equivalent values (TEQ), revealed a LD50 of 1 ng TEQ/g lipid, which is within the same order of magnitude as TEQ levels found in fish from highly polluted areas. This study indicates that ELS fish tests that are terminated shortly after the fish becomes free-feeding, underestimate the toxic potential of compounds with low acute toxicity such as PCBs. Our prolonged ELS with this native marine flatfish suggests that reproductive success of fish populations at contaminated sites can be affected
    Bioassay directed identification of natural aryl hydrocarbon-receptor agonists in marmalade
    Ede, K.I. van; Li, A. ; Antunes Fernandes, E.C. ; Mulder, P.P.J. ; Peijnenburg, A.A.C.M. ; Hoogenboom, L.A.P. - \ 2008
    Analytica Chimica Acta 617 (2008)1-2. - ISSN 0003-2670 - p. 238 - 245.
    calux-bioassay - ah receptor - dioxins - feed - food - furocoumarins - validation - vegetables - activation - chemicals
    Citrus fruit and citrus fruit products, like grapefruit, lemon and marmalade were shown to contain aryl hydrocarbon receptor (AhR) agonists, as detected with the DR CALUX® bioassay. This is of interest regarding the role of the Ah-receptor pathway in the adverse effects of dioxins, PCBs and other aromatic hydrocarbons. So far it is unclear which compounds in citrus fruit are responsible for the AhR-mediated activity and whether regular exposure to these compounds can cause effects comparable to, e.g. dioxins. The present study aimed at developing a method for identifying unknown Ah-receptor agonists in citrus products based on bioassay directed analysis, using marmalade as a first target. Following extraction with hexane and purification on an aluminium oxide-column, the extract was fractionated by HPLC using a C-18 semi-preparative column. Fractions were extracted, solvent-exchanged into dimethylsulfoxide and subsequently tested with DR CALUX®. Extracts were shown to contain primarily coumarins, furocoumarins (FCs) and polymethoxyflavones (PMFs). Identification of fractions most active in the bioassay via LC/MS revealed that bergapten (an FC) is the most important Ah-receptor agonist in marmalade. The approach and method developed resulted in the successful identification of the bioactive component. However, potential pitfalls of the procedure will be discussed
    Ah receptor agonist activity in frequently consumed food items
    Waard, W.J. de; Aarts, J.M.M.J.G. ; Peijnenburg, A.A.C.M. ; Kok, T.M.C.M. de; Schooten, F.J. van; Hoogenboom, L.A.P. - \ 2008
    Food Additives and Contaminants 25 (2008)6. - ISSN 0265-203X - p. 779 - 787.
    aryl-hydrocarbon receptor - cytochrome-p450 1a1 - mediated activity - calux-bioassay - in-vitro - indole-3-carbinol - dioxins - activation - 2,3,7,8-tetrachlorodibenzo-p-dioxin - indolo<3,2-b>carbazole
    The aryl hydrocarbon receptor (AhR) receives much attention for its role in the toxicity of dioxins and dioxin-like polychlorinated biphenyls. However, many other compounds have also been reported to bind and activate AhR, of which natural food components are of special interest from a human health perspective. Using the dioxin receptor-chemical-activated luciferase gene expression (DR CALUX®) bioassay, extracts from many food items frequently consumed in the Netherlands were screened to estimate the intake of natural AhR agonists (NAhRAs). Using the prototypical AhR agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as standard, it was estimated that the daily intake of NAhRAs might be considerably higher than the reported intake of dioxins and dioxin-like polychlorinated biphenyls. Potatoes, cruciferous vegetables, bread, hamburgers, and grapefruit juice contained most NAhRAs. Food preparation and acid treatment can show a significant effect on AhR activation. The interaction of natural and xenobiotic AhR agonists should be taken into account when performing risk-benefit analysis of both types of compounds
    Cumulative risk assessment of the exposure to organophosphorus and carbamate insecticides in the dutch diet
    Boon, P.E. ; Voet, H. van der; Raaij, M.T.M. van; Klaveren, J.D. van - \ 2008
    Food and Chemical Toxicology 46 (2008)9. - ISSN 0278-6915 - p. 3090 - 3098.
    pesticide-residues - toxicity - mechanism - dioxins - pcbs
    We report the acute cumulative exposure to organophosphorus insecticides (OPs) and carbamates in the Dutch population and young children (1-6 years) via the diet. Residue data were derived from Dutch monitoring programmes performed during 2003-2005, and food consumption levels from the Dutch National Food Consumption Survey 1997/1998. The relative potency factor (RPF) approach was used to cumulate the exposure to OPs and carbamates using acephate and oxamyl as index compound respectively. The exposure was estimated using the probabilistic approach, including unit variability and processing effects. We demonstrate that about 3% of the composite samples analysed for OPs and 0.2% for carbamates contain combinations of these pesticides. The P99.9 of exposure to OPs and carbamates in the total Dutch population equals 23 and 0.64mug/kg BW/d respectively. For young children the corresponding exposure levels are 57 and 1.47mug/kg BW/d. When comparing the P99.9 of exposure with the ARfD, 50 and 9mug/kg BW/d for acephate and oxamyl respectively, there is only a possible health risk for young children. Spinach contributed most to the exposure to OPs in both age groups, followed by orange and mandarin. For carbamates apple (sauce) was the main product determining the exposure.
    Beheersing dioxines in eieren van leghennen met buitenloop = Controlling egg dioxin levels from laying hens with outdoor run
    Kijlstra, A. ; Traag, W.A. ; Hoogenboom, L.A.P. - \ 2008
    Lelystad : Animal Sciences Group (Rapport / Animal Sciences Group 123) - 25
    pluimveehouderij - hennen - biologische landbouw - eieren - dioxinen - bodemverontreiniging - monitoring - dierhouderij - pluimvee - uitloop - poultry farming - hens - organic farming - eggs - dioxins - soil pollution - monitoring - animal husbandry - poultry - outdoor run
    Dioxin levels in organic eggs can be controlled by regulating outdoor run use via the moment that the barn doors are opened and by providing feed and water inside. In case of high environmental pollution the soil in the outdoor run needs to be replaced. Thanks to a dioxin monitoring protocol, action can be taken as soon as levels approach threshold levels
    Gezondheid van biologische leghennen
    Fiks-van Niekerk, T.G.C.M. ; Bestman, M.W.P. ; Wagenaar, J.P. ; Krimpen, M.M. van; Mul, M.F. ; Kijlstra, A. ; Reimert, H.G.M. ; Reuvekamp, B.F.J. - \ 2008
    Lelystad : Animal Sciences Group (Boek / Animal Sciences Group nr. 5) - 80
    biologische landbouw - pluimveehouderij - hennen - diergezondheid - dierenwelzijn - vaccinatie - verenpikken - hennenvoeding - wormen - bacterieziekten - salmonella - escherichia coli - brachyspira - aviaire influenzavirussen - infectieus bronchitisvirus - voedselveiligheid - dioxinen - dierhouderij - pluimvee - organic farming - poultry farming - hens - animal health - animal welfare - vaccination - feather pecking - hen feeding - helminths - bacterial diseases - salmonella - escherichia coli - brachyspira - avian influenza viruses - infectious bronchitis virus - food safety - dioxins - animal husbandry - poultry
    Dit boekje bevat een bundeling van reeds eerder uitgegeven artikelen en brochures van ASG en LBI over gezondheid van biologische leghennen. Tevens zijn enkele nieuwe stukken toegevoegd over onderwerpen die voor de biologische leghennenhouderij van belang zijn.
    Qualitative screening and quantitative determination of pesticides and contaminants in animal feed using comprehensive two-dimensional gas chomatography with time-of-flight mass spectrometry
    Lee, M.K. van der; Weg, G. van der; Traag, W.A. ; Mol, J.G.J. - \ 2008
    Journal of Chromatography. A, Including electrophoresis and other separation methods 1186 (2008)1-2. - ISSN 0021-9673 - p. 325 - 339.
    gc x gc - fish feed - organochlorine pesticides - extraction - residues - pressure - volumes - dioxins - fruit - pcbs
    A method has been developed for the target analysis of over 100 pesticides and contaminants in a complex feed matrix. The method is based on extraction with ethyl acetate, cleanup by gel permeation chromatography (GPC) and dispersive solid-phase extraction (SPE) with primary secondary amine phase (PSA), and analysis by comprehensive two-dimensional gas chromatography with full scan time-of-flight mass spectrometric detection (GC × GC¿TOF-MS). Parameters studied during method development included a dispersive SPE cleanup step after GPC, large volume injection into the GC system and the GC × GC separation. Qualitative and quantitative performance of the GC × GC system was evaluated by analyzing spiked extracts in the range equivalent to 1¿100 ¿g/kg in feed. At levels of 50 ¿g/kg and higher, all compounds targeted for could be identified fully automatically by the software based on their mass spectra. At lower levels the hit rate decreased with the concentration. System linearity was excellent in solvent and only slightly affected by matrix (correlation coefficients r ¿ 0.995 for 90% of the compounds). Limits of quantification were in the 1¿20 ¿g/kg range for most compounds. The overall method was validated for 106 compounds at the 10 and 100 ¿g/kg level. Recoveries between 70% and 110% and RSDs below 20% were obtained for the majority of the compounds.
    Alternative Legehennenhaltung in der Praxis Ein lagebericht aus den Niederlanden
    Groot Koerkamp, P.W.G. ; Kijlstra, A. - \ 2008
    Rundschau für Fleischhygiene und Lebensmittelüberwachung 60 (2008)1. - ISSN 0178-2010 - p. 20 - 27.
    pluimveehouderij - kippen - voedselkwaliteit - hygiëne - diergezondheid - dierenwelzijn - dioxinen - polychloorbifenylen - huisvesting van kippen - biologische landbouw - bedrijfshygiëne - poultry farming - fowls - food quality - hygiene - animal health - animal welfare - dioxins - polychlorinated biphenyls - chicken housing - organic farming - industrial hygiene
    Informatie over omvang en grootte van kippenhouderijen in Nederland en de verdeling per bedrijfssysteem.
    Sand intake by laying hens and its effect on egg production parameters
    Meulen, J. van der; Kwakernaak, C. ; Kan, C.A. - \ 2008
    Journal of Animal Physiology and Animal Nutrition 92 (2008)4. - ISSN 0931-2439 - p. 426 - 431.
    whole barley - performance - dioxins - grit - soil - chicken - animals - energy - diets - feed
    Soil intake may be the most prominent source of environmental contaminants for free range and organic hens, but there are no quantitative data concerning soil intake by domestic hens. Consumption of soil of 14¿32 g a day can be estimated from literature, but such a dilution of nutrient intake seems incompatible with high productivity. In this study laying hens were fed pelleted diets with 0%, 10%, 20%, 25% and 30% of sand addition to determine its effect on productivity. Feed intake, feed and nutrient (feed minus sand) conversion ratio, egg production, egg weight and body weight gain were measured over a 4-week period. Acid insoluble ash concentration in the faeces was measured to determine the accuracy of estimating the soil ingestion by the soil-ingestion equation for wildlife as a way to determine soil ingestion of free range and organic hens under practical circumstances. The hens were able to compensate the dilution of the diet with 20%, 25% and 30% of sand by increasing their feed intake. Feed intake increased significantly and feed to egg conversion ratio decreased significantly with increasing sand levels in the diet. The nutrient to egg conversion ratio of the diet without sand tended to be worse than for the diets with sand, presumably due to the total absence of coarse material in the diet. There were no differences in egg production and egg weight between hens fed the different diets but body weight gain was significantly lower for the hens fed the diets with 20%, 25% and 30% of sand. Estimation of sand ingestion was done by the soil-ingestion equation for wildlife. Provided that the actual dry matter digestibility coefficient of the nutrient part of the diet is taken into account, estimating the soil ingestion according to the soil-ingestion equation for wildlife seems an appropriate way to determine soil ingestion for free range and organic hens under practical circumstances.
    Effect of flock Size on Dioxin Levels in eggs from Chickens kept Outside
    Kijlstra, A. ; Traag, W.A. ; Hoogenboom, L.A.P. - \ 2007
    Poultry Science 86 (2007)9. - ISSN 0032-5791 - p. 2042 - 2048.
    biologische landbouw - pluimveehouderij - scharrelhouderij - eieren - dioxinen - uitloop - organic farming - poultry farming - free range husbandry - eggs - dioxins - outdoor run - laying hens - range - contamination - soil - pcbs - wildlife - systems - area
    To decrease dioxin uptake by the general population the European Union (EU) has set limits to the dioxin content of many foodstuffs including eggs. Eggs from free foraging chickens are known to have a higher dioxin content compared with confined laying hens, and the question is whether these eggs can adhere to current EU regulations. The aim of the study was to investigate parameters that are involved in the contamination of eggs from chickens raised under organic conditions. Samples from 34 organic farms including soil and earthworm samples were collected between September and December of the year 2003. Dioxin levels were assayed by gas chromatography-mass spectrometry. Various parameters were collected by on farm interviews. Egg dioxin content varied between 0.4 and 8.1 pg of toxic equivalents (TEQ)/g of egg fat with a mean of 2.2 pg of TEQ/g of egg fat. Nine out of 34 farms exceeded the EU limit of 3 pg of TEQ/g of egg fat. In addition, dioxin-like polychlorinated biphenyls (DL-PCB) were measured, and 8 samples exceeded the limit for the sum of dioxins and DL-PCB. Overall, egg samples from 10 farms were noncompliant with the dioxin or total TEQ limits. No statistically significant relation could be observed between egg dioxin levels and the concentration observed in soil or earthworms. A statistically significant association was observed between flock size and egg dioxin and DL-PCB content. This effect is most likely attributable to the fact that flock size is related to the time chickens spend outside. Restricting outdoor run use on one of the farms resulted in a decrease of the egg dioxin content to a level that was within the EU limits. This demonstrates that the most likely contamination source is the soil or soil organisms but that the behavior of the hens determines the extent of the contamination. Following the completion of this study, a dioxin monitoring protocol has been set up in the Netherlands to prevent marketing of eggs with raised dioxin levels.
    Trendanalyse van gehalten aan aflatoxine B1 en dioxinen/dioxine-achtige PCB's in diervoeders
    Adamse, P. ; Jong, J. de; Jongbloed, A.W. ; Raamsdonk, L.W.D. van; Egmond, H.J. van - \ 2007
    Wageningen : RIKILT (Rapport / RIKILT 2007.001) - 49
    diervoeding - veevoeding - besmetters - voedselbesmetting - kennis - voedselveiligheid - aflatoxinen - dioxinen - ruwe grondstoffen - voedselketens - polychloorbifenylen - animal nutrition - livestock feeding - contaminants - food contamination - knowledge - food safety - aflatoxins - dioxins - raw materials - food chains - polychlorinated biphenyls
    In dit rapport wordt met behulp van historische waarden inzicht gegeven in het verloop van de gehalten aan contaminanten in diervoeders in Nederland. Het onderzoek heeft zich in eerste instantie beperkt tot het analyseren van trends in het vóórkomen van aflatoxine B1 en dioxinen/dioxineachtige PCB's in een beperkte selectie diervoedergrondstoffen.
    Onderzoek naar dioxines, dioxine achtige PCB's en indicator-PCB's in paling uit Nederlandse binnenwateren
    Hoogenboom, L.A.P. ; Kotterman, M.J.J. ; Hoek-van Nieuwenhuizen, M. van; Lee, M.K. van der; Traag, W.A. - \ 2007
    Wageningen : RIKILT (Rapport / RIKILT 2007.003) - 32
    palingen - waterverontreiniging - dioxinen - polychloorbifenylen - nederland - kennis - binnenwateren - ecotoxicologie - eels - water pollution - dioxins - polychlorinated biphenyls - netherlands - knowledge - inland waters - ecotoxicology
    In deze inventariserende studie werden 62 monsters paling uit open water onderzocht op dioxines en PCB’s, afkomstig van 22 verschillende locaties en in meerderheid gebieden waar hoge gehaltes verwacht werden.
    Onderzoek dioxines in gras en bodem in de Rijnmond en de overdracht naar melk
    Traag, W.A. ; Zeilmaker, M. ; Eijkeren, J.C.H. ; Hoogenboom, L.A.P. - \ 2006
    Wageningen : RIKILT (Rapport / RIKILT 2006.015) - 21
    dioxinen - grassen - bodem - analytische methoden - melk - nederland - kennis - rijnmondgebied - dioxins - grasses - soil - analytical methods - milk - netherlands - knowledge - rijnmondgebied
    Onderzoek naar dioxinegehaltes in door particulieren geteelde groenten en fruit afkomstig uit de Rijnmond
    Traag, W.A. ; Hoogenboom, L.A.P. ; Portier, L. ; Ede, K.I. van; Heneweer, M. ; Immerzeel, J. ; Onstenk, C.G.M. ; Kraats, C. van de; Velthuis, E.G. ; Vlaanderen, J. van - \ 2006
    Wageningen : RIKILT (Rapport / RIKILT 2006.012) - 13
    dioxinen - voedselbesmetting - groenten - vruchten - nederland - kennis - rijnmondgebied - dioxins - food contamination - vegetables - fruits - netherlands - knowledge - rijnmondgebied
    Dioxins in organic eggs: a review
    Vries, M. de; Kwakkel, R.P. ; Kijlstra, A. - \ 2006
    NJAS Wageningen Journal of Life Sciences 54 (2006)2. - ISSN 1573-5214 - p. 207 - 221.
    dioxinen - toxicologie - eieren - bodemchemie - diervoedering - biologische landbouw - kwaliteitsnormen - dioxins - toxicology - eggs - soil chemistry - animal feeding - organic farming - quality standards - dibenzo-p-dioxins - adaptive significance - chickens - tissue - soil - 2,3,7,8-tetrachlorodibenzo-p-dioxin - bioaccumulation - biotransfer - metabolism - excretion
    Eggs contribute for about 4% to the daily dioxin intake of humans. Research among layer farms in the Netherlands and other EU countries has shown that organic eggs contain more dioxin than conventional ones and that a significant number of organic farms produce eggs with a dioxin content that exceeds the EU standard. The hens' intake of dioxins from various sources leads to an increase in the dioxin content of organic eggs. These sources include plants, feed, soil, worms and insects, and compared with hens on conventional and free-range farms, organic hens make more use of these sources due to better access to the outdoor run. Plants appear to be relatively unimportant as a source of dioxins. Also commercial organic feed generally has very low dioxin contents, but not much is known about non-commercial feed. Consumption of worms and insects and particularly ingestion of soil are important causes of high dioxin levels in eggs. Management interventions, like a reduction of the time the hens spend outside, may decrease the dioxin levels in organic eggs but at the same time may interfere with the image of the organic production systems
    Development, validation and routine application of the in vitro REA and DR-CALUX reporter gene bioassays for the screening of estrogenic compounds and dioxins in food and feed
    Bovee, T.F.H. - \ 2006
    Wageningen University. Promotor(en): Ivonne Rietjens; Ron Hoogenboom; Michel Nielen. - [S.l.] : S.n. - ISBN 9789085043935 - 133
    biotesten - dioxinen - oestrogenen - bioassays - dioxins - oestrogens
    A dedicated cell-line was developed by the Department of Toxicology of Wageningen University in a joined project with the University of California in Davis and the RIKILT-WUR - Institute of Food Safety in Wageningen. This DR-CALUX ® bioassay was tested, optimised and validated for its use to determine low elevated levels of dioxins in bovine milk around the existing limits. It was shown that this mammalian cell based test is very sensitive for 2,3,7,8-substituted dioxins and related PCBs, thereby reflecting the relative potencies (TEF) of these compounds as set by the World Health Organisation (WHO). These toxic equivalency factors (WHO-TEFs) express the toxicity of a compound in comparison to the most toxic compoundcongener 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, TEF=1). The response obtained with a mixture of dioxins was additive, in accordance with the TEQ-principle. Milk fat was isolated by centrifugation followed by clean-up of the fat with n-pentane, removal of the fat on a 33% H2SO4silica column, and determination of Ah receptor agonist activity with the DR-CALUX ® bioassay. To investigate the performance of this 33% H2SO4silica method, milk fat was cleaned with activated carbon and spiked with a mixture of 17 different 2,3,7,8-substituted PCDD and PCDF congeners at 1, 3, 6, 9, 12 and 15 pg WHO-TEQ per g fat, as confirmed by GC/MS. In this concentration range, the method showed a recovery of TEQs around 67% (58-87%). The reproducibility showed a coefficient of variation (CV) varying between 4% and 54%, with the exception of the sample spiked at 1 pg WHO-TEQ/g (CV 97%). The repeatability determined with the sample spiked at 6 pg WHO-TEQ per g showed a CV of 10% These results clearly demonstrate that the reproducibility of the silica-CALUX procedure with samples containing more than 1 pg WHO-TEQ per g fat is relatively good, in particular regarding the fact that no internal standards could be used in the assay for correction of data for varying recoveries. The fact that the CV was much higher for the sample spiked at the lowest level, confirmed the calculated limit of quantification of 1 pg WHO-TEQ per g fat. The current tolerance limit for bovine milk in the EU is 3 pg WHO-TEQ per g fat, with an action limit of 2 pg WHO-TEQ per g fat. Therefore, the DR-CALUX ® bioassay can be a useful pre-screening tool for selecting milk samples that may contain dioxin levels exceeding this tolerance limit. This was supported by the results obtained with 22 field samples, since all five samples exceeding the 2 pg WHO-TEQ per g fat concentration gave a higher response in the DR-CALUX ® bioassay.

    The DR-CALUX ® bioassay in combination with the 33% H2SO4clean-up procedure results in a specific test for the determination of dioxins and dioxin-like PCBs, allowing the screening of relatively large sets of samples for the presence of unacceptable high levels of these compounds. This results in a reduction of costs involved in the analysis of food for the presence of these compounds, enabling more intense monitoring programs.

    Following the successful optimisation and validation of the test for milk fat, the bioassay was first used at RIKILT in the food and feed area during the 1998 Brazilian citrus pulp incident. The test procedure was subsequently optimised and validated for animal feed. During the German bakery waste incident in 2003, animal feed was contaminated with dioxins due to the use of waste wood for drying of the material. Besides Germany, the material was also shipped to the Netherlands. Levels up to 12 ng WHO-TEQ/kg were detected, being about 15 times over the current limit of 0.75 ng WHO-TEQ/kg. A combined strategy of screening with the DRCALUX ® -bioassay and the HRGC/HRMS confirmatory method was used in the Netherlands to rapidly control the incident. Pigs were contaminated by the incident but only to a very limited extent. Despite the rather low limits for pig meat (1 pg WHO-TEQ per g fat), the DR-CALUX ® bioassay, in combination with an extra acid pre-treatment of the fat samples, showed excellent performance, confirming once again the value of this bioassay. Shown during the recent incidents with kaolinic clay (2004) and the contaminated HCl used for gelatine production (2006), the assay is still the best availablescreening test for dioxins and dioxin-like PCBs.

    The second aim of the research in this thesis was to develop, validate and apply a new recombinant yeast screen to detect chemicals with an estrogenic mode of action in animal feed, urine and illegal preparations. A recombinant yeast cell that stably expresses the human estrogen receptor α (hERα) and yeast enhanced green fluorescent protein (yEGFP) as a reporter protein in response to estrogens was developed at the RIKILT. The EC50 revealed by the RIKILT yeast Estrogen bioAssay (REA) was 0.5 nM for 17b-estradiol and was comparable with reported EC50 values for yeast estrogen bioassays that contain β-galactosidase as a reporter. However, the yEGFP assay can be performed completely in 96 well plates within 4 hours and does not need require cell wall disruption, nor does it need the addition of a substrate. This makes the test sensitive, rapid and convenient with high reproducibility and small variation. The robustness and ease of the yeast cells in combination with the qualities ofyEGFP,ensure that the assay will be suited to be used as a high through put system.

    The properties of the RIKILT yeast Estrogen bioAssay expressing thehERα(REA) were further studied by testing a series of estrogenic compounds. In addition, a similar assay was developed based on the stable expression of human estrogen receptor β (hERβ). When exposed to 17b-estradiol, the maximum transcriptional activity of the hERb cytosensor was only about 40% of the activity observed with hERa, but the concentration where half-maximal activation is reached (EC50), was about 5 times lower. The relative estrogenic potencies (REP), defined as the ratio between the EC50 of 17b-estradiol and the EC50 of the compound, of the synthetic hormones dienestrol, hexestrol and especially mestranol were higher with ERa than with ERβ, while DES was slightly more potent with ERb. The gestagens progesterone and medroxyprogesterone-acetate showed no response, whereas the androgen testosterone showed a very weak response and only at high concentrations. The isoflavones genistein, genistin, daidzein and daidzin, the coumestran coumestrol and the flavonoid naringenin were relatively more potent with ERb than with ERa. Coumestrol and genistein were by far the most potent of these compounds with ERb. However, 8-prenylnaringenin, a phytoestrogen present in hops, was relatively more potent with ERa than with ERb and was actually the most potent phytoestrogen with ERa. The data demonstrate that the REA shows clear dose-response curves when exposed to estrogenic compounds. Since good dose-response curves can be obtained after only 4 h of exposure, the often questioned permeability of the yeast cell wall does not seem to be an obstacle in our yeast estrogen bioassays.

    The RIKILT yeast Estrogen bioAssay stably expressing human estrogen receptor α (REA) was validated as a qualitative screening method for the determination of estrogenic activity in calf urine and animal feed. These validations were performed according to EC Decision 2002/657, which prescribes the determination of the detection capability (CCb), the specificity and the stability. To determine these performance characteristics, twenty blank urine samples of 19 week old calves were collected and spiked with 17b-estradiol (E2b) at 1 ng/ml-1, diethylstilbestrol (DES) at 1 ng/ml-1, 17a-ethynylestradiol (EE2) at 1 ngml-1a-zearalanol at 50 ngml-1 or mestranol at 10 ng/ml-1. Following enzymatic deconjugation and solid phase extraction, 100 ml equivalents of these blank and spiked urine samples were screened for estrogenic activity in a 96 well plate using the REA. All of these blank and low estrogen spiked feed samples fulfilled the CCα and CCβ criterions, meaning that all 20 blank urine samples gave a signal below the determined decision limit CCα and were thus classified as compliant and at least 19 out of the 20 spiked samples gave a signal above this CCα (β=5%) and were thus classified as suspect. The specificity of the method was determined with blank urine samples spiked with a high dose of testosterone or progesterone (1000 ng/ml-1). No response to these substances was detected in the REA. There was also no interference of a high dose of testosterone or progesterone on the response of a low dose of the estrogens. Stability of urine samples was checked with spiked urine samples that were kept frozen for up to 90 days, showing that urine samples could be stored at -20°C for up to 60 days without changing the screening result of the assay. The assay was validated for animal feed in a simalar way, using twenty blank animal feed samples, including milk replacers and wet and dry feed samples.

    As all the performance characteristics met the criteria that were put forward in EC Decision 2002/657 for validation of a qualitative screening method, the described clean-up/yeast estrogen bioassay procedures were proven to be valid for the determination of estrogenic activity in calf urine and animal feed. The clean-up procedures for urine and feed samples are relatively simple and the yeast estrogen bioassay, using yEGFP as a reporter protein, is sensitive, rapid, convenient and reproducible. Due to the good sensitivity of the bioassay, only 2 ml of urine or 1 gram of feed were enough to be processed. Combined this resulted in a low cost bioassay that is suited to be used as a high through-put system for the screening of estrogenic activity in calf urine and animal feed. Like the DR CALUX ® assay, Tthe method acquired an ISO 17025 accreditation status in the Netherlands for both of these matrices. The examples of the MPA-incident with wet pig feed and the fishfeed,described in Chapter 7 of the thesis, demonstrate the applicability of the bioassay method as an early warning system for pharmaceutical waste and hormone use respectively. This is the first successful example of a developed, validated and applied bioassay for the screening of hormonal substances in feed. At present this method has been in routine use at RIKILT for more than two years.

    Overall the work presented in this thesis shows that bioassays are valuable tools for rapid and high throughput screening of samples for both known and unknown compounds. As such they may contribute to an earlier detection of new emerging risks and prevent the use of illegal growth-promoting agents with thus far unknown identity.
    Inventarisatie en evaluatie dioxinen in het Nederlandse aquatische milieu: status 2005
    Leonards, P.E.G. ; Dulfer, W.J. ; Evers, E.H.G. ; Guchte, C. van de - \ 2005
    IJmuiden : RIVO (Rapport / Nederlands Instituut voor Visserij Onderzoek (RIVO) C061/05-A) - 45
    dioxinen - polychloorbifenylen - emissie - aquatische ecologie - aquatisch milieu - dioxins - polychlorinated biphenyls - emission - aquatic ecology - aquatic environment
    This report describes an inventory of the present day’s situation of actions and effects of actions on the emission of dioxin, furan and dioxin-like PCBs to the Dutch aquatic environment. The standards for dioxins, furans and dioxin-like PCBs in food and the environment, and a risk evaluation for local areas in the Netherlands in relation to the function of the water are discussed.
    Dioxins in Food and Feed - Reference Methods and New Certified Reference Materials (DIFFERENCE)
    Leeuwen, S.P.J. van; Goeyens, L. ; Loco, J. van; Carbonelle, S. ; Overmeire, I. van; Beernaert, H. ; Cleuvenbergen, R. van; Schoeters, G. ; Bjoerklund, E. ; Sporring, S. ; Abalos, M. ; Abad, E. ; Rivera, J. ; Santos, J. ; Traag, W.A. ; Hoogenboom, R. ; Haglund, P. ; Wiberg, K. ; Holst, C. von; Maquet, A. ; Pasini, A.L. ; Fraise, D. ; Becher, G. ; Korytar, P. ; Leonards, P.E.G. ; Boer, J. de - \ 2005
    IJmuiden : RIVO (Report / RIVO-Netherlands Institute for Fisheries Research no. C022/05) - 75
    dioxinen - voedselanalyse - voedselveiligheid - vergelijkingen - referentienormen - polychloorbifenylen - polychloordibenzodioxinen - dioxins - food analysis - food safety - comparisons - reference standards - polychlorinated biphenyls - polychlorinated dibenzodioxins
    The European research project DIFFERENCE (“Dioxins in Food and Feed – Reference methods and New Certified Reference Materials”) was focussed on the development of an alternative methods for analysis of polychlorinated dibenzodioxins (PCDDs), dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) using comprehensive multi-dimensional gas chromatography (GC×GC), gas chromatography combined with low resolution ion-trap mass spectrometry (GCLRMS/ MS), the CALUX bioassay and an Ah-PCR technique. GC combined with high resolution mass spectrometry (HRMS) was used as a reference method in all comparisons.
    Effects of In Utero Exposure to 4-hydroxy-2,3,3',4',5-pentachlorobiphenyl (4-OH-CB107) on Developmental Landmarks, Steroid Hormone Levels, and Female Estrous Cyclicity in Rats
    Meerts, I.A.T.M. ; Hoving, S. ; Berg, J.H.J. van den; Weijers, B.M. ; Swarts, J.J.M. ; Beek, E.M. van der; Bergman, A. ; Koeman, J.H. - \ 2004
    Toxicological sciences 82 (2004)1. - ISSN 1096-6080 - p. 259 - 267.
    polychlorinated-biphenyls aroclor-1254 - hydroxylated pcb metabolites - reproductive decline - mouse - hypothyroidism - dioxins - dibenzofurans - inhibition - induction - estradiol
    Previous studies have revealed that one of the major metabolites of PCBs detected in human blood, 4-OH-2,3,3',4',5-pentaCB (4-OH-CB107), accumulated in fetal liver, brain, and plasma and reduced maternal and fetal thyroid hormone levels after prenatal exposure to pregnant rats from gestational days (GD) 10¿16. In the present study, the effects of 4-OH-CB-107 on developmental landmarks, steroid hormone levels, and estrous cyclicity of rat offspring after in utero exposure to 4-OH-CB107 was investigated. Pregnant rats were exposed to 0, 0.5, and 5.0 mg 4-OH-CB107 per kg bw from GD 10 to GD 16. Another group of rats was exposed to Aroclor 1254 (25 mg/kg bw) to study the differences between effects caused by parent PCB congeners and the 4-OH-CB107 alone. A significant, dose-dependent prolongation of the estrous cycle was observed in 75% and 82% of female offspring exposed to 0.5 and 5.0 mg 4-OH-PCB107, respectively, compared to 64% of Aroclor 1254 (25 mg/kg) exposed offspring. The diestrous stage of the estrous cycle was prolonged, resembling a state of pseudopregnancy, which might reflect early signs of reproductive senescence. Plasma estradiol concentrations in female rat offspring were significantly increased (50%) in the proestrous stage after exposure to 5 mg 4-OH-CB107 per kg bw. No effects on estradiol levels were observed in Aroclor 1254 treated animals. These results indicate that in utero exposure to 4-OH-CB107 leads to endocrine-disrupting effects, especially in female offspring. The possible impact on neurobehavior following exposure to 4-OH-CB107 will be reported elsewhere
    Carry-over of dioxins and PCBs from feed and soil to eggs at low contamination levels
    Traag, W.A. ; Kan, C.A. ; Zeilmaker, M. ; Hoogerbrugge, R. ; Eijkeren, J. van; Hoogenboom, L.A.P. - \ 2004
    onbekend : Rikilt - Institute of Food Safety (Report / RIKILT 2004.016) - 77
    pluimveehouderij - dioxinen - polychloorbifenylen - voedselbesmetting - bodemverontreiniging - bioaccumulatie - poultry farming - dioxins - polychlorinated biphenyls - food contamination - soil pollution - bioaccumulation
    In order to study the relationship between dioxin and PCB levels in feed and eggs, laying hens were fed with compound feed containing six different levels of dioxins, dioxin-like PCBs and indicator PCBs for a period of 56 days. This was followed by a period of another 56 days on clean feed.Data were successfully modelled in order to predict the levels after different exposure scenario’s. Overall, these data show that exposure to dioxins and dioxin-like PCBs rapidly results in increased levels in eggs and that the current EU limit for feed cannot guarantee egg levels below the EU-limit. Therefore, dioxin levels in chicken feed should be as low as possible and the current limit for dioxins in feed should be further reduced, at least in the case of chicken feeds. More in general, it is important to further harmonize the tolerance limits for feed and edible products like meat, eggs and milk. Information about the carry-over of contaminants in farm animals is essential for this purpose.
    Is saneren wel altijd nodig?
    Jonker, M.T.O. ; Koelmans, A.A. ; Sinke, A. ; Brils, A. - \ 2004
    H2O : tijdschrift voor watervoorziening en afvalwaterbehandeling 37 (2004). - ISSN 0166-8439 - p. 28 - 30.
    verontreinigingsbeheersing - polychloorbifenylen - polycyclische koolwaterstoffen - dioxinen - besluitvorming - schoonmaken - waterorganismen - waterbodems - pollution control - polychlorinated biphenyls - polycyclic hydrocarbons - dioxins - decision making - cleaning - aquatic organisms - water bottoms
    Recent onderzoek heeft aangetoond dat zowel roet- en kooldeeltjes als verweerde olieresiduen giftige organische verontreinigingen,zoals PAK, extreem sterk kunnen binden. Deze materialen zijn wijd verspreid in waterbodems en kunnen ervoor zorgen dat de giftige stoffen vele malen minder worden opgenomen door organismen dan tot nu toe werd aangenomen. De huidige risico-evaluatieprocedure voor waterbodems gaat volledig voorbij aan dit feit, waardoor risico's kunnen worden overschat. Het is daardoor mogelijk dat saneringen plaatsvinden die in feite niet noodzakelijk zijn. De in dit onderzoek ontwikkelde methode kan helpen om hierover uitsluitsel te geven
    Intra- and interlaboratory calibration of the DR Calux bioassay for the analysis of dioxins and dioxin-like chemicals in sediments
    Besselink, H.T. ; Schipper, C.A. ; Klamer, H. ; Leonards, P.E.G. ; Verhaar, H. ; Felzel, E. ; Murk, A.J. ; Thain, J. ; Hosoe, K. ; Schoeters, G. ; Legler, J. ; Brouwer, A. - \ 2004
    Environmental Toxicology and Chemistry 23 (2004)12. - ISSN 0730-7268 - p. 2781 - 2789.
    dioxinen - toxiciteit - biotesten - waterbodems - ecotoxicologie - dioxins - toxicity - bioassays - water bottoms - ecotoxicology - equivalency factors tefs - in-vitro bioassay - round-robin - pcbs - pcdds - pcdfs - support - water - assay
    In the Fourth National Policy Document on Water Management in the Netherlands, it is defined that in 2003, in addition to the assessment of chemical substances, special guidelines for the assessment of dredged material should be recorded. The assessment of dredged material is based on integrated chemical and biological effect measurements. Among others, the DR CALUX® (dioxin responsive–chemically activated luciferase expression) bioassay has tentatively been recommended for inclusion in the dredged material assessment. To ensure the reliability of this bioassay, an intra- and interlaboratory validation study, or ring test, was performed, organized by the Dutch National Institute for Coastal and Marine Management (RIKZ) in cooperation with BioDetection Systems BV (BDS)
    In the Fourth National Policy Document on Water Management in the Netherlands [1], it is defined that in 2003, in addition to the assessment of chemical substances, special guidelines for the assessment of dredged material should be recorded. The assessment of dredged material is based on integrated chemical and biological effect measurements. Among others, the DR CALUX(R) (dioxin responsive-chemically activated luciferase expression) bioassay has tentatively been recommended for inclusion in the dredged material assessment. To ensure the reliability of this bioassay, an intra- and interlaboratory validation study, or ring test, was performed, organized by the Dutch National Institute for Coastal and Marine Management (RIKZ) in cooperation with BioDetection Systems BV (BDS). The intralaboratory repeatability and reproducibility and the limit of detection (LOD) and quantification (LOQ) of the DR CALUX bioassay were determined by analyzing sediment extracts and dimethyl sulfoxide (DMSO) blanks. The highest observed repeatability was found to be 24.1%, whereas the highest observed reproducibility was calculated to be 19.9%. Based on the obtained results, the LOD and LOQ to be applied for the bioassay are 0.3 and 1.0 pM, respectively. The interlaboratory calibration study was divided into three phases, starting with analyzing pure chemicals. During the second phase, sediment extracts were analyzed, whereas in the third phase, whole sediments had to be extracted, cleaned, and analyzed. The average interlaboratory repeatability increased from 14.6% for the analysis of pure compound to 26.1% for the analysis of whole matrix. A similar increase in reproducibility with increasing complexity of handlings was observed with the interlaboratory reproducibility of 6.5% for pure compound and 27.9% for whole matrix. The results of this study are intended as a starting point for implementing the integrated chemical-biological assessment strategy and for systematic monitoring of dredged materials and related materials in the coming years.
    TIE-studie van dioxine-achtige stoffen in zwevend stof en sediment met behulp van de DR-CALUX assay en gas chromatografie met time-of-flight massaspectrometrie
    Leonards, P.E.G. ; Veen, I. van der; Hesselingen, J.M. van - \ 2004
    onbekend : RIVO Milieu en Voedselveiligheid (RIVO rapport C076/04) - 12
    dioxinen - gaschromatografie - massaspectrometrie - dioxins - gas chromatography - mass spectrometry
    In dit onderzoek werd de toxiciteit van dioxine-achtige stoffen met behulp van de DR-CALUX assay van zwevend stof en sediment monsters bepaald.
    Analyse van baggerslib met de DR-CALUX assay en een screening met gaschromatografie met time-of-flight massaspectrometrie
    Leonards, P.E.G. ; Hoek-van Nieuwenhuizen, M. van; Hesselingen, J.M. van - \ 2004
    onbekend : RIVO Milieu en Voedselveiligheid (RIVO rapport C066/04) - 17
    toxiciteit - dioxinen - mariene sedimenten - sediment - havens - anaërobe afbraak - verontreinigde sedimenten - toxicity - dioxins - marine sediments - sediment - harbours - anaerobic digestion - contaminated sediments
    In dit onderzoek werd de toxiciteit van dioxine-achtige stoffen met behulp van de DR-CALUX assay van sediment uit het Zeehavenkanaal van Delfzijl bepaald. De toxiciteit was vergelijkbaar met de resultaten uit het onderzoek van 2002. De activiteit van het sediment bewerkt met een niet-destructieve methode (GPC) was 100 maal hoger dan wanneer het sediment werd bewerkt met het standaard protocol (SPECIE-01) waarbij een chemisch agressieve methode wordt toegepast. Dit bevestigt de resultaten uit eerder onderzoek. Na 18 maanden van anaërobe degradatie van het sediment was de DR-CALUX activiteit van de totale hoeveelheid extraheerbare stoffen met een DR-CALUX activiteit onveranderd, maar een verhoging werd waargenomen voor de fractie waarin zich dioxinen, furanen en PCB’s bevonden. Onduidelijk is waardoor deze verhoging werd veroorzaakt. Echter een sterke afname in DRCALUX activiteit werd gevonden voor stoffen die biologisch beschikbaar zijn. In sediment werd een drietal stoffen (dichloroanthraceen, dichloro-lichexanthone, dichloorbenzidine) met gaschromatografie met time-of-flight massaspectrometrie geïdentificeerd. Deze stoffen bezitten mogelijk een DR-CALUX activiteit en kunnen daarom bijdragen in de dioxine-achtige toxiciteit. Uitgezocht zou moeten worden of deze stoffen inderdaad een activiteit bezitten en hoeveel van de toxiciteit verklaard kan worden.
    Overzicht dioxine proeven uitgevoerd in Nederland met koeien en schapen
    Kan, C.A. ; Meijer, G.A.L. - \ 2003
    Lelystad : ID-Lelystad (Rapport / ID-Lelystad 03/0000744)
    dioxinen - dierlijke producten - koeien - schapen - besmetting - toxische stoffen - dioxins - animal products - cows - sheep - contamination - toxic substances
    De problemen met dioxinen en dibenzofuranen in koeien en schapen in de omgeving van de Afvalverwerking Rijnmond (Lickebaert gebied 1985-1990) en de contaminatie van citruspulp (1998-1999) hebben aanleiding gegeven tot een aantal proeven. In deze notitie worden de belangrijkste gegevens van deze proeven samengevat. Doel van dit overzicht is om de huidige kennis en kennishiaten met betrekking tot risico's van overdracht van dioxine-achtige verbindingen naar het dierlijk product melk (en vlees) in kaart te brengen
    Steeds minder dioxinen, furanen en dioxineachtige PCB's in de voeding
    Boon, P.E. ; Klaveren, J.D. van; Bakker, M. ; Baumann, B. ; Hoogerbrugge, R. - \ 2003
    Voeding Nu 5 (2003)9. - ISSN 1389-7608 - p. 17 - 19.
    vissen - dioxinen - heterocyclische zuurstofverbindingen - herbicidenverontreinigingen - polychloorbifenylen - gechloreerde koolwaterstoffen - voedselveiligheid - voedselconsumptie - blootstelling - nederland - europa - fishes - dioxins - heterocyclic oxygen compounds - herbicide impurities - polychlorinated biphenyls - chlorinated hydrocarbons - food safety - food consumption - exposure - netherlands - europe
    Ondanks de steeds verder dalende dioxine- en PCB-gehalten in voedingsmiddelen verdienen deze stoffen ook in de toekomst blijvende aandacht. Dit geldt zeker voor PCB-gehalten in vis
    Voeding en gezondheid - toxische stoffen in de voeding
    Rietjens, I.M.C.M. ; Alink, G.M. - \ 2003
    Nederlands Tijdschrift voor Geneeskunde 147 (2003)48. - ISSN 0028-2162 - p. 2365 - 2370.
    voeding - toxinen - voedselbesmetting - verontreiniging - zware metalen - dioxinen - polychloorbifenylen - aromatische koolwaterstoffen - polycyclische koolwaterstoffen - aminen - acrylamiden - nutrition - toxins - food contamination - pollution - heavy metals - dioxins - polychlorinated biphenyls - aromatic hydrocarbons - polycyclic hydrocarbons - amines - acrylamides
    With respect to food, the most important factors causing adverse health effects are: an unbalanced diet, overconsumption of alcohol or fat, the presence of microbial contamination and the presence of natural toxines. Two additional factors, the presence of environmental contaminants and products formed on heating food, may also be of importance. It is generally assumed that, when combined, food-related factors contribute to around 35% of overall cancer incidence
    Effecten van hormoonverstorende stoffen op kikkers
    Lee-de Groot, M.B.E. ; Brink, N.W. van den; Hout, A. van der; Bie, P.A.F. de; Stumpel, A.H.P. ; Bosveld, A.T.C. - \ 2003
    Wageningen : Alterra (Alterra-rapport ) - 77
    amphibia - estradiol - dioxinen - toxicologie - voortplantingsorganen - mortaliteit - hormonen - biotesten - ecotoxicologie - hormoonverstoorders - amphibia - estradiol - dioxins - toxicology - reproductive organs - mortality - hormones - bioassays - ecotoxicology - endocrine disruptors
    Omdat de ontwikkeling van amfibieën sterk hormoon-gereguleerd is, is onderzocht in hoeverre de kikker een geschikte indicator is voor hormoonverstorende stoffen in het milieu. Hiertoe zijn in het laboratorium blootstellingstudies uitgevoerd met kikkerlarven en volwassen Rana kikkers, welke algemeen in Nederland voorkomen. Onderzocht is in hoeverre oestradiol (E2) en tetrachloordibenzo-p-dioxine (TCDD) de ontwikkeling, overleving, lichaams- en orgaangewichten, geslachtsorganen en -hormonen, en specifieke cytochroom P450 enzymen beïnvloeden. Ook is de onderlinge samenhang van deze ettectparameters bestudeerd. In een in-situ veldstudie zijn de overleving en ontwikkeling van larven van Rana Kikkers, die zijn uitgezet in de sterk verontreinigde Volgermeerpolder en een niet-verontreinigde referentielocatie, beschouwd. Naast dit alles zijn juveniele Rana kikkers gevangen uit beide locaties, waarin interne concentraties dioxine-achtige stoffen en activiteiten van specifieke cytochroom P450 enzymen zijn bepaald.
    Validatie en toepassing van de CALUX-bioassay voor diervoeders
    Traag, W.A. ; Hoogenboom, L.A.P. - \ 2001
    Wageningen : RIKILT (Rapport / Rijks-Kwaliteitsinstituut voor land- en tuinbouwprodukten RIKILT 2001.004) - 12
    biotesten - dioxinen - voer - citruspulp - screenen - bioassays - dioxins - feeds - citrus pulp - screening
    Dioxins and dioxin-like PCBs in foodstuffs : occurrence and dietary intake in the Netherlands at the end of the 20th century
    Freijer, J.I. - \ 2001
    Bilthoven etc. : RIVM [etc.] (RIVM report 639102022)
    dioxinen - polychloorbifenylen - voedingsmiddelen - voedselproducten - landbouwproducten - voedselconsumptie - voedselopname - nederland - dioxins - polychlorinated biphenyls - foods - food products - agricultural products - food consumption - food intake - netherlands
    Information on the occurrence of dioxins and dioxin-like PCBs in foodstuffs in the Netherlands. The data collected during measurement programmes on occurrence were combined with food consumption data to assess the dietary intake of dioxins and dioxin-like PCBs in the general population.
    Validatie van biomarkers voor de bepaling van effecten van doorvergiftiging in terrestrische fauna : effecten van TCDD en PAK in de huisspitsmuis (Crocidura russula)
    Bosveld, A.T.C. ; Bie, P.A.F. de - \ 2001
    Wageningen : Alterra (Alterra-rapport 154) - 75
    crocidura russula - benzopyreen - aromatische koolwaterstoffen - toxische stoffen - dioxinen - toxicologie - verontreiniging - biochemische merkers - biologische indicatoren - ecotoxicologie - crocidura russula - benzopyrene - aromatic hydrocarbons - toxic substances - dioxins - toxicology - pollution - biochemical markers - biological indicators - ecotoxicology
    Om eventuele effecten van PAK's bij kleine zoogdieren uit de wilde fauna te kunnen herkennen is in een viertal blootstellingstudies onderzocht wat de effecten zijn van benzo[a]pyreen (BaP) of een mengsel van negen verschillende polycyclische aromatische koolwaterstoffen (PAK). Daarnaast is het effect onderzocht van tetrachloordibenzo-p-dioxine (TCDD), als modelstof voor de veroorzakers van Ah receptor gemedieerde effecten. Het onderzoek is verricht aan de huisspitsmuis (Crocidura russula), een algemeen in het wild voorkomend klein zoogdier. In de verschillende studies zijn het verloop van het lichaamsgewicht en verschillen in orgaangewichten beschouwd naast de effecten op cytochroom P450 enzymen (EROD, MROD, PROD, BROD en specifieke testosteronhydroxylases) en de histopathologie van de geslachtsorganen.
    Scenario studies on maximum levels for dioxins, dibenzofurans and dioxin-like PCBs in fish
    Hoogenboom, L.A.P. ; Klaveren, J.D. van; Baars, A.L. ; Leeuwen, F.X.R. van; Hoogerbrugge, R. ; Leeuwen, S.P.J. van; Boer, J. de - \ 2001
    Unknown Publisher - 29
    dioxinen - polychloorbifenylen - besmetters - voedselbesmetting - vis - visproducten - voeding en gezondheid - voedselveiligheid - dioxins - polychlorinated biphenyls - contaminants - food contamination - fish - fish products - nutrition and health - food safety
    Dioxins, dibenzofurans and dioxin-like polychlorinated biphenyls (together called 'dioxins') are persistent environmental contaminants with a comparable chemical structure and similar toxicological characteristics. Since fish is one of the food items containing variable and sometimes high amounts of dioxins, the authorities asked RIVM, RIKILT and RIVO to investigate the possibility of setting maximum levels for dioxins in fish in order to protect fish consumers from high intake of these contaminants. To this, scenario studies were performed estimating the effect of several hypothetical maximum levels for dioxins in fish on the intake of these compounds by fish consumers and the percentage of various fish species that can be expected not to comply with these maximum levels. The studies show that in general the intake reduction will be limited to about 2-8%, while the percentage of non-compliance varies between 0.1 and 10. The available datasets on which these estimations had to be based are very limited. Moreover, the regular consumption of fish has positive health effects too due to the amounts of -3 unsaturated fatty acids.
    Verontreinigingen in visserijproducten consequenties van nationale en europese normstelling
    Boer, J. de - \ 2001
    Aquacultuur 16 (2001)2. - ISSN 1382-2764 - p. 23 - 26.
    vis - visproducten - visconsumptie - voedselveiligheid - wetgeving - voedingsmiddelenwetgeving - voedselinspectie - normen - kwaliteitsnormen - verontreiniging - verontreinigende stoffen - toxische stoffen - polychloorbifenylen - dioxinen - palingen - voedselbesmetting - Nederland - fish - fish products - fish consumption - food safety - legislation - food legislation - food inspection - standards - quality standards - pollution - pollutants - toxic substances - polychlorinated biphenyls - dioxins - eels - food contamination - Netherlands
    Vissen vormen vaak een vergaarbak van allerlei verontreinigingen in het milieu. Uitleg over de belangrijkste groepen verontreiniging, de normstelling voor visserijproducten m.b.t. deze stoffen (WHO-richtwaarden voor de aanvaardbare dagelijkse inname; Warenwet), en resultaten van onderzoek van het RIVO naar gehalten aan PCBs en dioxine in visserijproducten, met name paling van diverse locaties. Een te verwachten verdere verscherping van de normen zal vermoedelijk consequenties hebben voor de aalvisseij op de grote rivieren; het gebruik van sterk met dioxine verontreinigde visolie en vismeel bij het kweken van vis zou zoveel mogelijk beperkt moeten worden
    ANI - voedselfrequentievragenlijst 97/98 : 1. blootstelling aan dioxinen via de voeding : 2. rapportage consumptiegegevens
    Dooren-Flipsen, M.M.H. van; Donkersgoed, G. van; Klaveren, J.D. van - \ 1999
    Wageningen : RIKILT-DLO (Rapport / RIKILT-DLO 99.004) - 148
    voedselconsumptie - dioxinen - voedselsamenstelling - consumptiepatronen - consumenteninformatie - consumenten - nederland - food consumption - dioxins - food composition - consumption patterns - consumer information - consumers - netherlands
    Dioxinetest RIKILT heeft zijn waarde bewezen
    Mengelers, M.J.B. ; Hoogenboom, L.A.P. ; Traag, W.A. - \ 1999
    Voedingsmiddelentechnologie 4 (1999)23. - ISSN 0042-7934 - p. 13 - 16.
    dioxinen - heterocyclische zuurstofverbindingen - analytische methoden - testen - controle - kwalitatieve analyse - toxische stoffen - chemische samenstelling - chemische eigenschappen - voedselbesmetting - voedingsmiddelen - voedselindustrie - voedseltechnologie - analytische scheikunde - dioxins - heterocyclic oxygen compounds - analytical methods - testing - control - qualitative analysis - toxic substances - chemical composition - chemical properties - food contamination - foods - food industry - food technology - analytical chemistry
    Sinds 1992 werkt het Rikilt in samenwerking met de Wageningen Universiteit aan een biologische methode voor het screenen van agrarische producten op dioxinen en dioxineachtige PCB's. De methode is gevalideerd voor het aantonen van dioxinen in melk en in citruspulp uit Brazilie
    Vergelijking extractiemethoden voor de bepaling van bestrijdingsmiddelen, polychloorbiphenylen en polygechloreerde dibenzo-p-dioxinen, dibenzofuranen in grond
    Zuidema, T. ; Traag, W.A. - \ 1998
    Wageningen : RIKILT-DLO (Rapport / RIKILT-DLO 98.001) - 17
    pesticiden - grondanalyse - polychloorbifenylen - polychloordibenzofuranen - dioxinen - bodemverontreiniging - pesticides - soil analysis - polychlorinated biphenyls - polychlorinated dibenzofurans - dioxins - soil pollution
    Biodegradatie van micro-verontreinigingen met behulp van schimmeltechnologie: PCB's, HCH, DDT en dioxinen
    Traag, W.A. ; Zuidema, T. ; Camp, H.J.M. Op den; Pol, A. ; Griensven, L.J.L.D. Van - \ 1998
    Wageningen : RIKILT-DLO (Rapport / DLO-Rijks-Kwaliteitsinstituut voor Land- en Tuinbouwprodukten 98.017) - 2
    bioremediëring - biodegradatie - polychloorbifenylen - hch - ddt - dioxinen - paddestoelen - bodemverontreiniging - bioremediation - biodegradation - polychlorinated biphenyls - hch - ddt - dioxins - mushrooms - soil pollution
    Literatuurstudie naar methoden voor de bepaling van bestrijdingsmiddelen, polychloorbifenylen en polygechloreerde dibenzo-p-dioxinen, dibenzofuranen in grond
    Traag, W.A. ; Zuidema, T. - \ 1997
    Wageningen : RIKILT-DLO (Rapport / DLO-Rijks-Kwaliteitsinstituut voor Land- en Tuinbouwprodukten 97.25) - 17
    polychloorbifenylen - dioxinen - polychloordibenzofuranen - gaschromatografie - nederland - literatuuroverzichten - bodemverontreiniging - polychlorinated biphenyls - dioxins - polychlorinated dibenzofurans - gas chromatography - netherlands - literature reviews - soil pollution
    Human dietary intake of dioxins and planar PCBs in The Netherlands - average, population groups and time trends
    Dooren-Flipsen, M.M.H. van; Klaveren, J.D. van; Liem, A.K.D. - \ 1997
    Wageningen : RIKILT-DLO (Report / DLO-State Institute for Quality Control of Agricultural Products (RIKILT-DLO) 97.36) - 35
    voedselhygiëne - consumptiepatronen - dioxinen - polychloorbifenylen - nederland - food hygiene - consumption patterns - dioxins - polychlorinated biphenyls - netherlands
    De bodemgesteldheid van het saneringsgebied Lickebaert : resultaten van een bodemgeografisch onderzoek
    Scholten, A. ; Brouwer, F. - \ 1995
    Wageningen : DLO-Staring Centrum (Rapport / DLO-Staring Centrum 162) - 68
    bodemkarteringen - kaarten - dioxinen - bodemverontreiniging - nederland - zuid-holland - bodemsanering - soil surveys - maps - dioxins - soil pollution - netherlands - zuid-holland - soil remediation
    Thyroid hormone binding proteins as novel targets for hydroxylated polyhalogenated aromatic hydrocarbons (PHAHs) : possible implications for toxicity
    Lans, M.C. - \ 1995
    Agricultural University. Promotor(en): J.H. Koeman; A. Brouwer. - S.l. : Lans - ISBN 9789054854302 - 152
    polychloorbifenylen - dioxinen - pentachloorfenol - organische halogeenverbindingen - gehalogeneerde koolwaterstoffen - schildklierhormonen - polychlorinated biphenyls - dioxins - pentachlorophenol - organic halogen compounds - halogenated hydrocarbons - thyroid hormones

    Some toxic effects caused by polyhalogenated aromatic hydrocarbons (PHAHs) develop through alterations in the reproductive and thyroid hormone regulatory systems, thereby affecting (brain) development, reproduction and behaviour of several species (Stone, 1995, Birnbaum, 1994, for review: Brouwer et al. , 1995, Peterson et al. , 1993). In this thesis we have focused on the effects of different classes of PHAHs, eg. polychlorinated biphenyls (PCBs), dibenzofurans (PCDFs) and dibenzo- p -dioxins (PCDDs) and their hydroxylated metabolites on thyroid hormone homeostasis. These changes seem to be partly caused by Ah-receptor mediated changes in thyroid hormone glucuronidation, and effects on the thyroid gland affecting hormone production and secretion. However, hydroxylated metabolites of PCBs, PCDFs and PCDDs may have an additional effect on thyroid hormone transport. Previous studies (Brouwer, 1987) have shown that exposure to 3,3',4,4'- tetrachlorobiphenyl (TCB) can disturb the plasma transport of thyroxine (T 4 ) and retinol in rats through specific competition of a hydroxylated metabolite, 4-OH-3,3',4',5-tetraCB, with T 4 for the thyroid hormone binding site of transthyretin (TTR), the major thyroid hormone transport protein in rodents. This observation raised the question if structurally related hydroxylated PHAH- metabolites could interact with TTR in the same way, as well as with other thyroxine binding proteins, like thyroxine binding globulin (TBG) and type-1-deiodinase (ID-1), subsequently disturbing thyroid hormone transport and metabolism. Special attention was also paid on the structure-activity relationships of hydroxylated PHAH metabolites for binding to TTR by using in vitro and in vivo studies and X-ray crystallographic structure analysis,

    In vitro studies on interactions of hydroxylated PHAH metabolites with thyroxine binding proteins

    In in vitro studies the interactions of several hydroxylated PHAH metabolites with 3 different T 4 binding proteins, eg. TTR, thyroxine binding globulin (TBG) and type-1-deiodinase (ID-1), were investigated (Chapter 2, 3 and 4). The inhibition of T 4 binding to TTR by hydroxylated PHAH metabolites was studied using in vitro T 4 -TTR bindingstudies. These studies revealed the structural requirements for competition of T 4 binding to TTR by hydroxylated PHAH metabolites: para- or meta-hydroxylation on one or both phenylrings, with one or more adjacent chlorine substitutions (Chapter 2). PHAH metabolites with these structural characteristics showed a remarkable resemblance to T 4 the natural ligand for TTR, consequently displacing T 4 from the T 4 binding site of TTR. Both non-planar, ortho-chlorinated hydroxylated PCB metabolites and rigid, planar hydroxylated PCDF or PCDD metabolites could inhibit T 4 -TTR binding. However, the ortho-hydroxylated PHAH metabolites and parent PHAH compounds, like TCDD, 2,3,3',4,4'-pentaCB and 3,3',4,4'-tetraCB could not inhibit T 4 -TTR binding in vitro.

    In subsequent in vitro studies, a wide range of hydroxylated PHAH metabolites did not inhibit T 4 binding to TBG, the major plasma thyroid hormone transport protein in man (Chapter 3). This indicates that ligand interactions with TTR or TBG are clearly different. Additional studies with iodothyronine derivatives, showed that tri-iodophenol and to a lesser extent di-iodotyrosine could inhibit T 4 -TTR binding but not T 4 -TBG binding in vitro. Finally, the enzymatic activity of hepatic ID-1, which plays a role in the (in)activation of thyroid hormones, could be competitively inhibited mainly by di-para-hydroxylated, meta-halogenated PHAH metabolites while mono-hydroxylated PHAH metabolites were 10 to 100 times less potent (Chapter 4). The differences between the structural requirements of hydroxylated PHAH metabolites for interactions with TTR, TBG and ID-1, are in line with previous studies in which related hydroxylated PHAH compounds or iodothyronine derivatives were used. In conclusion, specific hydroxylated PHAH metabolites can disturb T4-TTR interactions, or inhibit ID-1 activity in vitro, indicating that hydroxylated PHAH metabolites may play an additional role in the observed disturbances in thyroid hormone transport and metabolism after PHAH exposure in vivo .

    In vivo studies on effects of Aroclor 1254 and TCDD on thyroid hormone transport and metabolism

    Two in vivo experiments were carried out to study role that both disturbances in plasma T 4 transport and hepatic T 4 metabolism caused by hydroxylated PHAH metabolites play in the observed decreases in plasma T 4 levels. Rats were exposed to Aroclor 1254, a commercial mixture containing persistent and metabolisable PCB congeners (Chapter 5) or the persistent 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD) (Chapter 6).

    In adult Wistar rats, that were exposed to a high dose of Aroclor 1254, plasma T 4 levels were decreased on day 3 and day 8 (Chapter 5). In addition, high levels of a single hydroxylated PCB metabolite, eg. 4-OH-2,3,3',4',5-pentaCB, were detected in plasma of the rats on day 8, while lower concentrations of this metabolite were present in the blood on day 3. However, the T 4 binding capacity in plasma was decreased only in the high dosed group on day 8 but not on day 3, indicating a threshold level for the hydroxylated PCB metabolite to disturb T 4 -TTR binding. On both day 3 and 8, hepatic cytochrome P450 1A1 levels and activity were induced, which is essential for the formation of hydroxylated metabolites. Hepatic T 4 glucuronidation was induced simultaneously. The decreased plasma T 4 levels found in all exposure groups could therefore be attributed to both disturbed plasma T 4 transport and/or induced T 4 glucuronidation. No significant changes in plasma T 3 levels were found following Aroclor 1254 treatment. In addition, hepatic ID-1 activity was not decreased, suggesting that the in vitro inhibition by hydroxylated PCB metabolites does not occur in vivo. However in an earlier study Adams et al. (1990), in vivo exposure to the easily metabolisable 3,3',4,4'-tetraCB or persistent TCDD could inhibit ID-1 activity. The levels of PCB metabolites with the required structure for inhibition of hepatic ID-1 activity were possibly too low (Chapter 4) liver after Aroclor 1254 exposure in vivo.

    Another remarkable finding was the selective retention of a single specific hydroxylated PCB metabolite, 4-OH-2,3,3',4',5-pentaCB, in plasma of rats exposed to a complex mixture of PCB congeners (Fig. 1). This was the result of the presence of PCB-congeners that strongly induce cytochrome P4501AI activity and PCB-congeners that could easily form hydroxylated PCB metabolites in the Aroclor 1254 mixture, and the strict selectivity of the TTR present in plasma retaining only hydroxylated PCB metabolites that meet the structural requirements as described in Chapter 2. Surprisingly the 4-OH- 2,3,3',4',5-pentaCB metabolite which was formed and selectively retained in plasma, has a hydroxy group on the highest chlorinated ring, in contrast to the expected formation of mainly metabolites with a para - or meta -hydroxy group on the least chlorinated ring. However, the inhibition potencies of T 4 -TTR binding for the 4-OH-2,3,3',4',5-pentaCB metabolite (Chapter 5) and the structurally related 4'-OH-2,3,3',4,5'-pentaCB metabolite (Chapter 2) were almost similar. There is no clear indication yet on the mechanism of selective retention of the 4-OH-2,3,3',4',5-pentaCB in rat plasma, although pharmacokinetics and tissue levels of the presumed parent compounds 2,3,3',4,4'- pentaCB (CB 105) or 2,3',4,4',5-pentaCB (CB 118) may play a role.

    No detectable levels of hydroxylated metabolites were found by GC-MS analysis of plasma extracts of rats at both day 3 and 8 following exposure to the persistent TCDD, although cytochrome P4501A1 levels and activity were markedly induced (Chapter 6). In addition no unequivocal decrease in T 4 -TTR binding in plasma of TCDD-exposed rats was observed. However, hepatic thyroid hormone metabolism was clearly altered: T 4 glucuronidation and brain type-2-deiodinase (ID-2) activity were increased and hepatic ID-1 activity was decreased, which may explain the observed plasma T4 reductions in the TCDD exposed rats. These changes in thyroid hormone homeostasis suggest a hypothyroxinemic state of the TCDD-exposed rats, although no decreased plasma T4 levels were found. The decrease in ID-1 activity after TCDD exposure was not likely to be caused by hydroxylated metabolites, as was described in Chapter 4, but may be caused by direct effects of TCDD on ID-1 activity or by the assumed hypothyroid state of the TCDD exposed rats.

    While Aroclor 1254 exposure disturbed T4 plasma transport and increase T 4 glucuronidation (Chapter 5), TCDD exposure only enhanced the hepatic elimination of T4 (Chapter 6), leading to decreased plasma T 4 levels. Although the in vivo studies described in this thesis indicate two different mechanisms for decreases in plasma T 4 levels after PHAH exposure, we can not exclude a third possible mechanism since several studies described changes on thyroid gland histology and thyroid hormone secretion after exposure to Aroclor 1254, TCDD and related compounds.

    Structural basis for interactions of hydroxy-PCB metabolites with TTR

    The selective retention of a specific hydroxylated PCB metabolite in vivo (Chapter 5), inspired us to look into the interactions of hydroxylated PCB metabolites with TTR in more detail, and to try to find a structural basis for the structural requirements for TTR binding as described in Chapter 2. X-ray crystallographic analysis of a complex of TTR with a hydroxylated PCB metabolite, eg. 4,4'- (OH) 2 -3,3',5,5'-tetraCB, refined to a 2.7 A resolution, revealed a hydrogen bond formation between a para-hydroxy group of the metabolite with the paired Serine 117 amino acid residues, present in the centre of the TTR binding channel (Chapter 7). The location of this hydroxylated PCB metabolite, deep in the binding channel, and the hydrogen bond formation could explain the stronger TTR binding affinity of this metabolite than the natural ligand T 4 . The chlorine atoms present on the meta-positions of the 4,4'-(OH) 2 -3,3',5,5'-tetraCB, metabolite, fitted easily in the T 4 -iodine binding pockets present in the TTR binding channel. Additional computer-assisted graphics modelling studies on the interactions of several hydroxylated PCB metabolites with TTR, showed that hydroxy groups present on meta-positions could also form hydrogen bonds with the paired Serine 117 residues in the centre of the binding channel (Chapter 7). Furthermore, the modelling studies showed no significant differences between the interactions of hydroxylated PCB metabolites and the structurally related pentachlorophenol (PCP) with TTR, although in vivo studies by others indicated the disruption of the complex of retinol binding protein (RBP) and TTR after binding of a hydroxylated PCB metabolite but not by PCP in rodents. In conclusion, the detailed structural studies described in Chapter 7 confirmed the necessity of para- or meta- hydroxylation and adjacent chlorine substituents as structural elements of hydroxylated metabolites of PCBs and related compounds for interactions with TTR (Chapter 2), leading to selective retention of a specific hydroxylated PCB metabolite in plasma of rats exposed to a complex PCB mixture in vivo (Chapter 5).

    Concluding remarks

    The outcome of the present study clearly reveals the structural requirements that are essential for interactions of PHAH metabolites and other related chemicals for interactions with TTR. Hydroxylated PHAH metabolites can structurally resemble the thyroid hormone T 4 Overall the structural requirements for TTR interaction were hydroxysubstitution on the para - or meta positions of one or both of the phenyl rings, with adjacent chlorine substitutions, herewith confirming some of the suggestions for TTR interactions of related hydroxylated PHAH metabolites by Rickenbacher et al . (1986). Especially the observation by X-ray crystallographic structure analysis that a hydrogen bond could be formed in the TTR binding channel upon binding of a hydroxylated PCB metabolite, provides strong evidence that para - or meta -hydroxylation of the PHAH compound forms an essential prerequisite for binding to the T4 binding site of TTR. No interactions with TTR were found for the tested parent PHAH compounds, contradictory to earlier suggestions of McKinney et al. (1985) which were based mainly on computer modelling and few in vitro binding studies (Rickenbacher et al , 1986). It should be noted that graphics modelling may show that parent PHAH compounds may fit the TTR binding site, but gives little information on binding affinity to TTR. In an affirmative in vitro T 4 -TTR binding assay, several parent PCB congeners (3,3',4,4'-tetraCB, 3,3',4,4',5-pentaCB, 3,3',4,4',5,5'-hexaCB, 2,3,3',4,4'-pentaCB, 2,2',5,5'- tetraCB), TCDD and Aroclor 1254, a commercial PCB mixture, were tested at high concentrations and exhibited no inhibition of T 4 -TTR binding (unpublished data).

    Fig. 1.

    PHAH metabolites that are predicted to have high binding affinities for TTR are indeed detected in plasma of rodents experimentally exposed to PCBs or PCDFs (Morse et al ., 1995b, Koga et al ., 1990, Kuroki et al. , 1993). For instance, exposure to a complex mixture of PCBs, Aroclor 1254, led to the selective retention in blood of a single PCB metabolite, 4-OH-2,3,3',4',5- pentaCB, which met the structural requirements for TTR binding (Bergman et al ., 1994).

    On the basis of the proposed structural requirements we can give an explanation for the interactions of related compounds with TTR as found by others, for instance pentachlorophenol (Van den Berg, 1990, Van Raay et al ., 1994, Den Besten et al ., 1991), natural compounds like flavones and halogenated aurones (Cody, 1989; Ciszak et al ., 1992) and certain drugs like milrinone (Wojtczak et al. , 1993). Moreover, these structural insights make it possible to predict whether other related classes of environmental contaminants can interact with TTR. In addition, due to combined exposure in the environment, one may expect additivity of binding to TTR of hydroxylated PHAH metabolites with other structurally related environmental or natural compounds.

    An important question is whether these experimental data can be extrapolated to other species. Two factors are essential for the TTR mediated selective retention of hydroxylated PHAH metabolites namely the presence of TTR in blood and the formation of relevant PHAH metabolites. It is most likely that hydroxylated. metabolites can be formed in many species other than rodent. Recently hydroxylated PCB metabolites were identified in human and seal plasma, which were environmentally exposed to background PCB levels (Bergman et al. , 1994). The major metabolites were again the 4-OH-2,3,3',4',5-pentaCB metabolite and to a lesser extent 4-OH-2',3,3',4',5-pentaCB in seal and human plasma and 4-OH-2,2',3,4',5,5',6-heptaCB in human plasma. Thus the hydroxylated PCB metabolites detected in vivo completely matched the structural requirements for TTR binding. The PHAH metabolite patterns in plasma of both experimentally and environmentally exposed animals and humans are species specific and depend not only on the structural requirements for binding to TTR, but also on the exposure situation and the capacity of biotransformation of PHAHs of the species.

    The species-specific metabolism of PHAHs decreases in the order: terrestrial mammals>aquatic mammals>birds>fish (Safe, 1989). Several mammalian and avian species, like rats, seals, porpoises and eiderducks could form hydroxylated metabolites in in vitro microsomal incubations with the model substrate 3,3',4,4'-tetraCB (TCB). However fish, like trout and flounder, could not metabolise TCB, although cytochrome P4501A-like activity, responsible for biotransformation of planar PHAHs, can be induced (Murk et al., 1994, Morse et al., 1995c, Ishida et al., 1991).

    The selective retention of specific hydroxylated PHAH metabolites in plasma through binding to TTR is expected in species that both can metabolise PHAHs and posses TTR as a plasma thyroid hormone binding protein. TTR is a evolutionary conservative protein present in plasma of not only rodents but also other placental mammals, birds and to a lesser extent in reptiles. No TTR was detected in the lower species like fish and amphibians. In higher mammals like man, however, not only TTR but also thyroxine binding globulin (TBG), is present in blood as a primary thyroid hormone transport protein. In conclusion, hydroxylated PHAH metabolites can be formed and selectively retained by TTR in blood of a wide variety of species.

    The toxicological consequences of the TTR mediated selective retention of hydroxylated PHAH metabolites in plasma are not yet fully understood. The TTR protein plays a primary role in the transport of thyroid hormones in the blood of many species. Although TTR binds less T 4 than TBG in human serum, TTR may be responsible for much of the immediate delivery of T 4 and T 3 to cells due to the lower binding T 4 affinity. Furthermore TTR is important for the transport of retinol in blood by forming a complex with retinol-binding protein (Robbins, 1991).

    Disturbances in thyroid hormone plasma levels are found in several species experimentally or environmentally exposed to PHAHs, like rodents, seal (Brouwer et al., 1989) and man (Koopman Esseboom et al., 1994), species in which hydroxylated PCB metabolites were also present in plasma. Disruption of thyroid hormone homeostasis after exposure to PHAHs can however be caused by at least two mechanisms, eg. the disturbed plasma T 4 transport through competitive binding of hydroxylated PHAH metabolites to TTR, but also the Ah-receptor mediated induction of T 4 glucuronidation by parent compounds.

    The possible disruption of the TTR-RBP complex upon binding of a hydroxylated PHAH metabolite can also markedly decrease plasma retinol levels in rodents (Brouwer, 1987). It was suggested that seals exposed to PHAHs in the environment, have an impaired function of the immune system (de Swart, 1995), possibly resulting from disturbed retinoid levels (Brouwer, 1991, Brouwer et al. 1989). Hydroxylated PHAH metabolites may attribute to these effects on thyroid hormone and retinoid homeostasis through interactions with TTR in plasma. It is not known whether similar effects occur in man.

    TTR is the major thyroid hormone binding protein in cerebro-spinal fluid (CSF), suggesting a role in distribution of thyroid hormones in the central nervous system. This TTR is produced in the choroid plexus and is present in high concentrations in CSF of rats and humans, even at a very early stage in development. Moreover, in all species where TTR is present in blood, TTR has also been detected in brain. Because TTR is an important carrier for T 4 to target tissues, for instance brain, one may expect that it may also act as a facilitated transport system for hydroxylated PHAH metabolites. This is in accordance with observations of a strong accumulation of hydroxylated PCB metabolites of maternal origin in the plasma and brain of late gestational fetuses from pregnant rats or mice exposed to PCBs (Morse et al., 1995b,d, Darnerud et al., 1995). In rat fetuses perinatally exposed to Aroclor 1254 the selective accumulation of the 4-OH-2,3,3',4',5-pentaCB metabolite in maternal plasma and fetal plasma and brain led to decreases in brain T 4 levels, while brain T 3 levels were only lightly changed. In addition plasma and hepatic retinoid concentrations were decreased in fetal and neonatal offspring (Morse et al., 1995a). The hydroxylated metabolites accumulated to high levels in fetal rat brain and may themselves attributeto observed neurochemical changes (Morse, 1995).

    Hydroxylated PHAH metabolites have been shown to possess biological activity in vitro (Brouwer, 1994). Hydroxylated PCB metabolites can interfere with mitochondrial structure and function in vivo and in vitro (Lans et al., 1990, Narashimhan et al., 1991). Moreover, they can bind to the Ah-receptor and weakly induce EROD activity. In addition, an in vitro marker of tumor promoting potential, the gap-junctional intercellular communication, could be weakly inhibited. Hydroxylated PCB metabolites can also exert (anti)-estrogenic activities in vivo (Bergeron et al., 1994) and in vitro (Kramer et al., 1994). No clear structure activity relationships for (anti)- estrogenicity could be found for the tested hydroxylated PCB metabolites. However, the hydroxylated PCB metabolites selectively retained in fetal plasma and brain (Morse et al., 1995d) do have a weak (anti)-estrogenic activity. The intrinsic capacity to disrupt endocrine systems, eg. thyroid and estrogen status, and the relatively large accumulating levels of hydroxylated PCB metabolites in late gestational rat fetuses, suggests there is a potential risk for adverse developmental effects by these hydroxylated PHAHs. This possible hydroxy PCBmediated route of developmental toxicity should be investigated in a sound in vivo experimental setup.

    Subtle changes in plasma thyroid hormone levels and parameters for neurological development were described in children exposed to background levels of PHAHs in utero and through lactation (Koopman-Esseboom et al., 1994, Sauer et al., 1994, Pluim et al., 1993). Hydroxylated PHAH metabolites did not interact with TBG, the major T 4 binding protein in human plasma (Lans et al., 1994). However, the hydroxylated PCB metabolites which are recently detected in human plasma (Bergman et al., 1994) are mainly bound to TTR, as was found after selective purification of TTR from human plasma (unpublished results). Therefore TTR-mediated accumulation of hydroxylated PCB metabolites or related compounds in fetal plasma and brain and subsequent decreases in T 4 levels, as found in late gestational rat fetuses, may be of concern for fetal growth and (brain) development in a wide variety of species, including man.

    Onderzoek naar polygechloreerde dibenzo-p-dioxinen, dibenzofuranen en planaire gechloreerde bifenylen in Nederlandse melk
    Traag, W.A. ; Rhijn, J.A. van; Spreng, P.F. van de; Roos, A.H. ; Tuinstra, L.G.M.T. - \ 1993
    Wageningen : DLO-Rijks-Kwaliteitsinstituut voor Land- en Tuinbouwprodukten (Rapport / RIKILT-DLO 93.14) - 13
    melk testen - dioxinen - polychloorbifenylen - polychloordibenzofuranen - nederland - milk testing - dioxins - polychlorinated biphenyls - polychlorinated dibenzofurans - netherlands
    Bereiding van dioxinehoudende extracten ten behoeve van de Werkgroep Dioxine Emissies
    Rhijn, J.A. van - \ 1993
    Wageningen : DLO-Rijks-Kwaliteitsinstituut voor Land- en Tuinbouwprodukten (Rapport / RIKILT-DLO 93.05) - 7
    dioxinen - referentienormen - luchtverontreiniging - dioxins - reference standards - air pollution
    Preparation, homogeneity and stability of milkpowders containing polychlorodibenzo-P-dioxins and polychlorodibenzofuranes
    Roos, A.H. ; Tuinstra, L.G.M.Th. - \ 1992
    Wageningen : DLO-State lnstitute tor Quality Control of Agricultural Products (Report / RIKILT-DLO 92.02) - 15
    melkpoeder - dioxinen - polychloordibenzofuranen - referentienormen - dried milk - dioxins - polychlorinated dibenzofurans - reference standards
    Voor het Community Bureau of Raferenee (BCA) werden een "natuurlijk" gecontamineerd, een laag en een medium niveau gecontamineerd melkpoeder bereid. Van eenzelfde batch boterolie werden drie aparte batches bereid. Aan twee batches werd een verschillende hoeveelheid dioxine toegevoegd. Uitgaande van ondermelk werden met behulp van de drie batches boterolie drie batches melk bereid. Het dioxinengehalte in de drie batches, bepaald met behulp van internationaal geaccepteerde TEF waarden, bedraagt resp. ca. 3, 9 en 14 pg 1-TEQ/g melkvet. Een deel van elke batch melk werd gevriesdroogd en de rest werd verstoven. De aldus bereide gevriesdroogde melkpoeder werd gecontroleerd op homogeniteit en stabiliteit. Voor de homogeniteit werden het vetgehalte, Kjeldahl-N en PCB gehalte bepaald. De stabiliteit werd gecontroleerd in de gevriesdroogde melkpoeders die gedurende ca. één jaar bij -20°C, +20°C en 37°C waren opgeslagen.
    Het ontwikkelen van een methode voor de simultane bepaling van planaire chloorbiphenylen en polychloor dibenzo-P-dioxinen en furanen in melk
    Traag, W.A. ; Rhijn, J.A. van; Kulik, W. ; Spreng, P. van der; Tuinstra, L.G.M.Th. - \ 1992
    Wageningen : DLO-Rijks-Kwaliteitsinstituut voor Land- en Tuinbouwprodukten (Rapport / RIKILT-DLO 92.30) - 15
    melk testen - polychloorbifenylen - polychloordibenzofuranen - dioxinen - analytische methoden - milk testing - polychlorinated biphenyls - polychlorinated dibenzofurans - dioxins - analytical methods
    Ampullering van extracten van luchtmonsters ten behoeve van de analyse van dioxine
    Rhijn, J.A. van; Vries, P.H.U. de - \ 1992
    Wageningen : DLO-Rijks-Kwaliteitsinstituut voor Land- en Tuinbouwprodukten (Rapport / RIKILT-DLO 92.20) - 8
    dioxinen - luchtverontreiniging - bemonsteren - dioxins - air pollution - sampling
    Fate and effects of the insecticide Dursban 4E in indoor Elodea-dominated and macrophyte-free model ecosystems: 1. Fate and primary effects of the active ingredient chloropyrifos.
    Brock, T.C.M. ; Crum, S.J.H. ; Wijngaarden, R. van; Budde, B.J. ; Tijink, J. ; Zuppelli, A. ; Leeuwangh, P. - \ 1992
    Archives of Environmental Contamination and Toxicology 23 (1992)1. - ISSN 0090-4341 - p. 69 - 84.
    gewasbescherming - pesticiden - nadelige gevolgen - selectiviteit - toxiciteit - onbedoelde effecten - niet-doelorganismen - organo-fosforverbindingen - derivaten - chloride - fenolen - fenol - dioxinen - pentachloorfenol - milieu - verontreinigende stoffen - verontreiniging - plant protection - pesticides - adverse effects - selectivity - toxicity - nontarget effects - nontarget organisms - organophosphorus compounds - derivatives - chloride - phenols - phenol - dioxins - pentachlorophenol - environment - pollutants - pollution
    Uitscheiding van polygechloreerde dibenzo-p-dioxinen en -furanen in melk van koeien, die tijdens de droogstand zijn gevoerd met dioxinen besmet voer
    Roos, A.H. ; Berende, P.L.M. ; Traag, W.A. ; Rhijn, J.A. van; Mengelers, M.J.B. ; tUINSTRA, L.G.M.Th. - \ 1991
    Wageningen : RIKILT (Rapport / RIKILT 91-01) - 23
    rauwe melk - vervalsing - besmetting - polychloorbifenylen - polychloordibenzofuranen - dry lot feeding (voeding) - dioxinen - excretie - raw milk - adulteration - contamination - polychlorinated biphenyls - polychlorinated dibenzofurans - dry lot feeding - dioxins - excretion
    In dit verslag worden de resultaten beschreven van het onderzoek met melkgevende koeien die tot het moment van afkalven gevoerd zijn met dioxine-bevattend voer (tot aan het tijdstip van droogzetten in het Lickebaertgebied en na het droogzetten bij het IVVO te Lelystad). Na afkalven kregen de dieren "schoon" voer verstrekt. Bij aanvang van het experiment en vlak na het afkalven werden melkmonsters en vetbiopten genomen, Ook van de geboren kalveren werden direct na de geboorte o.a. subcutaan- en niervet en lever verzameld om de passage van de dioxinen door de uteruswand na te kunnen gaan. Het behulp van de verkregen resultaten kan in de toekomst aangegeven worden hoe lang na het afkalven gewacht moet worden voordat de melk van met dioxinen besmette dieren weer geconsumeerd kan worden. In dit verslag worden de resultaten van de dioxinenanalyses in de melk gerapporteerd.
    Histologische veranderingen bij koeien en schapen die in de praktijk en experimenteel blootgesteld zijn aan polygechloreerde dibenzo-p-dioxinen en -furanen
    Groot, M.J. ; Berende, P.L.M. ; Ossenkoppele, J.S. ; Tuinstra, L.G.M.Th. - \ 1991
    Wageningen : DLO-Rijks-Kwaliteitsinstituut voor Land- en Tuinbouwprodukten (Rapport / RIKILT-DLO 91.25) - 31
    koeien - dioxinen - polychloordibenzofuranen - microscopie - biopsie - schapen - histologie - cows - dioxins - polychlorinated dibenzofurans - microscopy - biopsy - sheep - histology
    Histologisch onderzoek is verricht op organen van koeien en schapen, welke chronisch en experimenteel bloot hebben gestaan aan dioxinen. Alle dieren waren op het moment van slachten klinisch gezond. Bij de meeste dieren werden histologische afwijkingen waargenomen. De waargenomen veranderingen kunnen niet zonder meer aan dioxinen worden toegeschreven aangezien de bodem van het gebied van herkomst van de dieren vervuild was met andere toxische stoffen (o.a. lood , cadmium, fluor, molybdeen), welke ook een bijdrage aan de waargenomen weefselveranderingen zullen hebben geleverd. Daarnaast betrof het oudere dieren waarvan de ziektegeschiedenis weinig bekend was.
    Het dioxinegehalte in Nederlandse visserijprodukten
    Hagel, P. - \ 1990
    IJmuiden : R.I.V.O. (Rapport / Rijksinstituut voor Visserijonderzoek, Afdeling Milieu-onderzoek MO 90-03) - 6
    dioxinen - visproducten - nederland - toxiciteit - ecotoxicologie - dioxins - fish products - netherlands - toxicity - ecotoxicology
    Onderzoek naar dioxinen en dibenzofuranen in Nederlandse melk en melkprodukten
    Roos, A.H. ; Hutzinger, O. ; Tuinstra, L.G.M.T. ; Huf, F.A. - \ 1989
    Wageningen : RIKILT (Rapport / RIKILT 89.41) - 18
    melk - melkproductie - voedselbesmetting - dioxinen - polychloordibenzofuranen - milk - milk production - food contamination - dioxins - polychlorinated dibenzofurans
    In opdracht van de directie Voedings- en Kwaliteitsaangelegenheden van het Ministerie van Landbouw en Visserij is als aanvulling van gegevens met betrekking tot gehalten van polychloordioxinen (PCDD) en polychloordibenzofuranen (PCDF) in melk in de omgeving van vuilverbrandingsinstallaties aanvullend onderzoek gedaan naar melk en melkprodukten uit onverdachte regio's.
    Schatting van de toxiciteit van enkele polychloordibenzo-p-dioxinen, polychloordibenzofuranen en polychloorbifenylen in Nederlandse paling in relatie tot de overige componenten uit deze groepen verbindingen
    Dorgelo, F.O. ; Roos, A.H. ; Kuiper, H.A. - \ 1988
    Wageningen : RIKILT (Rapport / RIKILT 88.49) - 28
    palingen - nederland - polychloorbifenylen - polychloordibenzofuranen - dioxinen - toxiciteit - risicoschatting - eels - netherlands - polychlorinated biphenyls - polychlorinated dibenzofurans - dioxins - toxicity - risk assessment
    Schatting van de toxiciteit van enkele polychloordibenzo-p-dioxinen, polychloordibenzofuranen en polychloorbifenylen in Nederlandse paling in relatie tot de overige componenten uit deze groepen verbindingen.
    Chemical porphyria in man. The diagnosis and occurrence of chronic hepatic porphyria in man caused by halogenated aromatics : Porphyrinogenic action of halogenated aromatics in experimental animals
    Strik, J.J.T.W.A. ; Koeman, J.H. - \ 1979
    Amsterdam : Elsevier - ISBN 9780444801593 - 236
    ziekten van de vrouwelijke geslachtsorganen - ziekten van de mannelijke geslachtsorganen - urinewegziekten - porfyrie - laboratoriumdieren - polybroombifenylen - polychloorbifenylen - dioxinen - female genital diseases - male genital diseases - urinary tract diseases - porphyria - laboratory animals - polybrominated biphenyls - polychlorinated biphenyls - dioxins
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