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.

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    We will mail you new results for this query: keywords==toxische stoffen
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Overdracht van contaminanten van moeder naar jong en chemische profielen in bruinvissen gestrand langs de Nederlandse kust
Heuvel-Greve, M.J. van den; Kwadijk, C.J.A.F. ; Kotterman, M.J.J. - \ 2016
Wageningen Marine Research (Rapport / Wageningen Marine Research C096/16) - 30 p.
phocoena - besmetters - overdracht - pasgeboren dieren - polychloorbifenylen - toxische stoffen - toxicologie - contaminants - transfer - newborn animals - polychlorinated biphenyls - toxic substances - toxicology
Nederland heeft ten aanzien van de bruinvis een beschermingsplicht onder de Natuurbeschermingswet 1998. Om deze plicht goed te kunnen invullen is in 2011 het Bruinvisbeschermingsplan opgesteld. Dit beschermingsplan laat een aantal kennisleemten zien, o.a. ten aanzien van de rol die verontreinigingen spelen in de sterfte onder bruinvissen. In de afgelopen decennia is het aantal bruinvissen dat aanspoelt langs de Nederlandse kust toegenomen. Om te bepalen of aanwezigheid en gehalten van contaminanten in aangespoelde bruinvissen mogelijke effecten hebben gehad op hun gezondheid, zijn een aantal specifieke kennisvragen opgesteld die in dit rapport worden beantwoord. Er is in dit onderzoek gebruik gemaakt van monsters van aangespoelde bruinvissen gevonden in zowel Nederland als Denemarken.
Persistent organic pollutants : aberrant DNA methylation underlying potential health effects
Dungen, M.W. van den - \ 2016
Wageningen University. Promotor(en): Tinka Murk; Ellen Kampman, co-promotor(en): Wilma Steegenga; Dieuwertje Kok. - Wageningen : Wageningen University - ISBN 9789462577893 - 207 p.
persistent organic pollutants - dna methylation - molecular genetics - epigenetics - health hazards - toxic substances - endocrine disruptors - eels - fish consumption - toxicology - persistente organische verontreinigende stoffen - dna-methylering - moleculaire genetica - epigenetica - gezondheidsgevaren - toxische stoffen - hormoonverstoorders - palingen - visconsumptie - toxicologie

Wild caught fish, especially marine fish, can contain high levels of persistent organic pollutants (POPs). In the Netherlands, especially eel from the main rivers have high POP levels. This led to a ban in 2011 on eel fishing due to health concerns. Many of the marine POPs have been related to adverse health effects such as endocrine disruption, neurodevelopmental problems, immune suppression and cancer. Although some mechanisms of action of POPs are clear, like dioxins binding to the aryl hydrocarbon receptor and OH-PCBs binding to thyroid transport proteins, not all adverse health effects can be explained by these mechanisms of action. Epigenetic phenomena, such as DNA methylation, have been proposed as a possible molecular mechanism underlying adverse health effects. DNA methylation is a heritable modification, which refers to the addition of a methyl group to cytosine in a CpG dinucleotide. Observational studies have indeed shown that POPs can affect global DNA methylation, although results are inconsistent. Some animal studies as well as in vitro experiments suggest that POPs can affect gene-specific DNA methylation, however, the biological significance and relevance for humans is not clear. Therefore, this thesis aimed to 1) study the accumulation of POPs in men consuming eel from high-polluted areas 2) elucidate whether seafood-related POPs can induce aberrant DNA methylation and 3) to determine whether DNA methylation is related to functional endpoints and gene expression in vitro.

For this purpose eight POPs that are abundantly present in seafood were chosen, namely 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), polychlorobiphenyl (PCB) 126 and 153, perfluorooctanesulfonic acid (PFOS), hexabromocyclododecane (HBCD), 2,2′,4,4′- tetrabromodiphenyl ether (BDE-47), tributyltin (TBT), and methylmercury (MeHg). Chapter 2 describes the in vitro effects of these POPs and mixtures thereof in H295R adrenocortical carcinoma cells. Relative responses for 13 steroid hormones and 7 genes involved in the steroidogenic pathway, and CYP1A1, were analysed. PFOS induced the most pronounced effects on steroid hormone levels by significantly affecting 9 out of 13 hormone levels measured, with the largest increases found for 17β-estradiol, corticosterone, and cortisol. Furthermore, TCDD, both PCBs, and TBT significantly altered steroidogenesis. Increased steroid hormone levels were accompanied by related increased gene expression levels. The differently expressed genes were MC2R, CYP11B1, CYP11B2, and CYP19A1 and changes in gene expression levels were more sensitive than changes in hormone levels. The POP mixtures tested showed mostly additive effects, especially for DHEA and 17β-estradiol levels. This study shows that some seafood POPs are capable of altering steroidogenesis in H295R cells at concentrations that mixtures might reach in human blood, suggesting that adverse health effects cannot be excluded. DNA methylation was not measured in this study due to the short exposure time, which was expected not to be sufficient for long-term epigenetic marks. Therefore, in chapters 3A and 3B a differentiation experiment was performed enabling long-term exposure to POPs. Human mesenchymal stem cells (hMSCs) were differentiated into mature adipocytes over a time-course of 10 days. The transcriptional regulatory cascade involved in adipocyte differentiation has been extensively studied, however the mechanisms driving the transcription are poorly understood. In chapter 3A we therefore first explored the involvement of DNA methylation in transcriptional regulation during adipocyte differentiation. Genome-wide changes in DNA methylation were measured as well as the expression of adipogenic genes. The majority of these genes showed significant expression changes during the differentiation process. There were, however, only a couple of these differentially expressed genes that were differentially methylated. Genome-wide DNA methylation changes were most often located in intergenic regions, and underrepresented close to the transcription start site. This suggested that changes in DNA methylation are not the underlying mechanism regulating gene expression during adipocyte differentiation. Nevertheless, we explored DNA methylation differences after continuous exposure to POPs to investigate whether this could be an underlying mechanism by which POPs affect adipocyte differentiation. TCDD and PFOS decreased lipid accumulation, while TBT increased lipid accumulation. TCDD and TBT induced opposite gene expression profiles, whereas after PFOS exposure gene expression remained relatively stable. Genome-wide DNA methylation analysis showed that all three POPs affected DNA methylation patterns in adipogenic and other genes, but without concomitant gene expression changes. Differential methylation was again predominantly detected in intergenic regions, where the biological relevance of alterations in DNA methylation is unclear. This study demonstrated that POPs, at environmentally relevant levels, are able to induce differential DNA methylation in differentiating adipocytes. However, the biological relevance of this aberrant DNA methylation remains unclear.

The in vitro results showed a proof of principle that POPs could be capable of altering DNA methylation. To this date, no human studies were performed investigating the relationship between POP levels and genome-wide DNA methylation. In order to investigate this, we first measured POP levels in eel consumers from the high-polluted areas (areas with a ban on eel fishing) and compared these levels to men consuming eel from low-polluted areas or aquaculture (chapter 4). We aimed to investigate the accumulation of these POPs and determine whether the predictions made in an earlier risk assessment were valid. This was indeed the case as levels of dioxins and dioxin-like compounds were on average 2.5 times higher in men consuming eel from high-polluted areas. Furthermore, PCBs with their hydroxylated metabolites, and perfluoroalkyl substances (PFASs) were, up to ten times, higher in these consumers. Especially the high levels of dioxins and dioxin-like compounds as well as the OH-PCBs are expected to be of health concern. We continued this research in chapter 5 by associating all the measured POPs to clinical parameters related to e.g. thyroid hormones and liver enzymes, but found no relationship. Subsequently, we investigated the association between dioxins and dioxin-like compounds, the sum of seven indicator PCBs, and PFOS with genome-wide DNA methylation. We detected a number of differentially methylated regions (DMRs) related to genes involved in carcinogenesis (e.g. BRCA1, MAGEE2, HOXA5), the immune system (e.g. RNF39, HLA-DQB1), in retinol homeostasis (DHRS4L2), or in metabolism (CYP1A1). In contrast to the in vitro data, most significant effects were detected in CpG islands and were annotated close to the promoter region. This suggests that the differential methylation might be related to differential expression and possibly induce adverse health effects. The hypermethylation of some of these gene related to cancer could be an explanation of the carcinogenic effects that are observed with POP exposure.

Based on the results of this thesis we can conclude that the consumption of eel from high-polluted areas lead to accumulation of POPs above safe levels and that POP levels are associated with gene-specific DNA methylation in vitro as well as in environmentally exposed men. More research, however, is needed to fully elucidate the biological implications of this aberrant DNA methylation. A first step can be to measure histone modifications, as these two epigenetic marks together are likely better in predicting gene expression. The second step can be to investigate the potential health effects related to these epigenetic marks and to determine whether there is a causal relationship. Although at this point there is a lack of knowledge with regard to health effects caused by DNA methylation, the consumption of eel from these high-polluted areas is ill- advised, because adverse health effects cannot be excluded based on our results and can even be expected based on literature.

Proteomics as a tool to gain more insight into sub-lethal toxicological effects
Miller, Ingrid - \ 2016
Wageningen University. Promotor(en): Tinka Murk, co-promotor(en): A.C. Gutleb; T. Serchi. - Wageningen : Wageningen University - ISBN 9789462578210 - 182 p.
proteomics - laboratory methods - sublethal effects - toxic substances - endocrine disruptors - food consumption - toxicology - animal experiments - eiwitexpressieanalyse - laboratoriummethoden - subletale effecten - toxische stoffen - hormoonverstoorders - voedselconsumptie - toxicologie - dierproeven

This thesis focuses on a modern analytical method, proteomics, to investigate its use in the field of toxicological research. Proteomics is a high resolution method which separates all proteins present in a sample at a clearly defined state and compares this pattern to another one, under slightly different conditions (e.g. after exposure to a chemical). Protein changes may give rise to or reflect disease/harm of the individual and can be attributed to alterations in body functions/regulation systems. Analysis conditions and different varieties of proteomic methods are explained, and a brief introduction given where proteomics is already applied in toxicology. A specific investigation has been performed with the flame retardant HBCD (i.e. hexabromocyclododecane). It is a compound that accumulates in lipid tissue from where it is only slowly removed. Its mechanism of action is not yet completely understood and sometimes seems to be contradictory. Rats were exposed to HBCD in very low doses for just one week and liver proteins were compared to those of unexposed animals. As HBCD is suggested to disturb the thyroid system, both healthy and hypothyroid rats were investigated, of both genders. In female rats, not in males, some specific liver protein changes were seen in glucose/carbohydrate and lipid metabolism, and also in some stress related proteins. Changes were not dependent on the thyroid function of the females. These results are in line with previous findings that female rats were more susceptible to HBCD than males. In a further step, protein patterns of unexposed animals of both genders were compared, revealing gender-dependent differences that exceeded the effects seen in any of the other comparisons, mainly in the pathways that were also affected by HBCD in females. A previous proteomic study on serum proteins has also shown clear gender-dependent concentration differences in rats. This underlines the importance of performing studies both in female and male individuals. The detection of considerable gender-dependent protein alterations confirms that proteomics is a biochemical tool with high sensitivity and large potential also in toxicological research.

Probabilistic dietary exposure models : relevant for acute and chronic exposure assessment of adverse chemicals via food
Boon, Polly E. ; Voet, H. van der - \ 2015
Bilthoven : RIVM (RIVM letter report 2015-0191) - 41 p.
exposure assessment - exposure - models - chemicals - toxic substances - intake - food consumption - food safety - probabilistic models - blootstellingsbepaling - blootstelling - modellen - chemicaliën - toxische stoffen - opname (intake) - voedselconsumptie - voedselveiligheid - waarschijnlijkheidsmodellen
Exposure models are used to calculate the amount of potential harmful chemicals ingested by a human population. Examples of harmful chemicals are residues of pesticides, chemicals entering food from the environment (such as dioxins, cadmium, lead, mercury), and chemicals that are generated via heating (such as acrylamide and furans). In this report we describe the characteristics of two types of models: the first for calculating the short term-intake, and the second for calculating long-term intake. These models currently result in the most realistic estimation of chemical intake via food.
Improvement of risk assessment by integrating toxicological and epidemiological approaches: the case of isoflavones
Islam, M.A. - \ 2015
Wageningen University. Promotor(en): Ivonne Rietjens; Rolaf van Leeuwen; Tinka Murk. - Wageningen : Wageningen University - ISBN 9789462574649 - 174
isoflavones - glucosides - soyabeans - toxic substances - bioavailability - biomarkers - human nutrition research - risk-benefit analysis - gene expression - isoflavonen - glucosiden - sojabonen - toxische stoffen - biologische beschikbaarheid - voedingsonderzoek bij de mens - risico-baten analyse - genexpressie

Improvement of risk assessment by integrating toxicological and epidemiological approaches: the case of isoflavones

PhD-thesis Mohammed Ariful Islam

This thesis describes the results of a research project that aimed at the improvement of the risk/benefit assessment of soy isoflavones (SIF) by combining toxicological and epidemiological methods. The toxicological studies were carried out at the Department of Toxicology and part of the results were compared with the outcome of human intervention studies, that were carried out in parallel research project at the Division of Human Nutrition. In Chapter 1 it is explained why we considered such an integrated “tox-epi” approach to be useful for the prediction of possible effects of SIF in humans on the basis of animal data. SIF are constituents of soy based supplements, which became more and more popular in Western societies over the last decades, because of their putative beneficial health effects, that were related to the SIF present in these supplements. In spite of the long and safe history of soy consumption by the East and the South-East Asian population, the benefit and safety of soy have been challenged in recent years and concerns have been raised about possible adverse health effects. These concerns focussed primarily on the weak estrogenic and proliferative effects of SIF. Chapter 1 also provides some background information on the individual SIF, their structural similarity with the steroid hormone estradiol (E2) and their interaction with the estrogen receptors ERα and ERβ.

Chapter 2 describes the differences between rats and humans in the conversion of the three major soy isoflavone glucosides, daidzin, genistin and glycitin, and their aglycones in a series of in vitro models. Results of studies in a Caco-2 transwell model confirmed that deconjugation of the isoflavone glucosides is essential for their transport across the intestinal barrier. It was shown that both rat and human intestinal S9 fractions were able to deconjugate the glucosides, and that intestinal enzymes plaid an important role in this deconjugation reaction. It was demonstrated that in the rat lactase phlorizin hydrolase, glucocerebrosidase, and cytosolic broad-specificity β-glucosidase contribute significantly to this deconjugation, and that in humans deconjugation mainly appeared to occur through the activity of broad-specificity β-glucosidase. Species difference in glucuronidation and sulfation were smaller than for the deconjugation reaction, and it was shown that 7-O-glucuronides were the major metabolites for all the three isoflavone aglycones. The in vitro results also indicated that glucuronidation in rats might be more efficient than in humans, again pointing towards species differences in the metabolism of isoflavone glycosides between rats and humans. It was also shown that the reconjugation reaction has a larger catalytic efficiency than the deconjugation of the glucosides, which corroborates that the detection of aglycones in the systemic circulation is unlikely.

It has been reported in literature that following administration of SIF to humans or animals, these compounds are mainly (~98%) present in the systemic circulation in their conjugated form (i.e. as glucuronide and sulphate) of which the estrogenic potency is not yet clear. Chapter 3 provides evidence that in an intact cellular model the major SIF glucuronide metabolites in blood, genistein-7-O-glucuronide (GG) and daidzein-7-O-glucuronide (DG), only become estrogenic after deconjugation. The estrogenic potencies of genistein (Ge), daidzein (Da), GG and DG were determined using stably transfected U2OS-ERα, U2OS-ERβ reporter gene cells and proliferation was tested in T47D-ERβ and in T47D breast cancer cells. In all these assays the estrogenic potency of the aglycones was significantly higher than that of their corresponding glucuronides. UPLC analysis revealed that in the in vitro cell line assays, 0.2-1.6% of the glucuronides were deconjugated to their corresponding aglycones. It was also found that, under similar experimental conditions, rat breast tissue S9 fraction was about 30 times more potent in deconjugating these glucuronides than human breast tissue S9 fraction. The results presented in Chapter 3 confirm that SIF glucuronides are not estrogenic as such when tested in an intact cellular model system, and that the small fraction of aglycones account for the observed estrogenic effects. They also provide evidence for a significant species difference in the metabolism of SIF.

In Chapters 4 and 5 of this thesis, two rat studies are described, that were performed to further elucidate important modes of action underlying biological effects of SIF and to facilitate an interspecies comparison of the effects observed in rats with those observed in human intervention studies. In these studies inbred ovariectomized Fischer344 rats were used, as an animal model for (post)menopausal women. In the first study described in Chapter 4, two dose levels (i.e. 2 and 20 mg/kg bw) were used to characterise plasma bioavailability, urinary and faecal concentrations of SIF and to investigate changes in gene expression in peripheral blood mononuclear cells (PBMC). The low dose was in line with the type of dosing relevant for human supplement use. Animals were dosed at 0 and 48 hr and sacrificed 4 hr after the last dose. A clear dose dependent increase of SIF concentrations in plasma, urine and faeces was observed, together with a strong correlation in changes in gene expression between the two dose groups. In the transcriptomic analysis, all estrogen responsive genes (ERG) and related biological pathways (BPs) that were found to be affected by the SIF treatment were regulated in both dose groups in the same direction, and indicate possible beneficial effects of SIF. However, most of the common genes in PBMC of rats and of (post)menopausal women, exposed to a comparable dose of the same supplement, were regulated in opposite direction. Thus based on these results no correlation was found between the changes in gene expression in rats and humans, leading to the conclusion that rats might not be a suitable model for humans.

In Chapter 5 an animal experiment is described, in which rats received a dose of 2 mg SIF/kg body weight per day for a period of eight weeks. This dosing regimen was similar as that of the parallel human intervention study. Changes in gene expression in different target (i.e. breast (BT), uterus (UT) and sternum (ST)) and non-target (i.e. peripheral blood mononuclear cells (PBMC), adipose (AT) and liver (LT)) tissues were compared. Rank-rank scattered plots did not show any correlation in gene expression changes among different tissues. Out of 87 estrogen responsive genes (ERG), only 19 were found to be significantly regulated (p<0.05) in different tissues. The significantly regulated ERG were mostly found in LT, AT and UT. Surprisingly, no ERG were significantly regulated in BT and ST, although these are considered to be important estrogen sensitive target tissues. No correlation was observed with the changes in gene expression in the PBMC of two rat studies. Correlation was also not seen in the changes of gene expression in PBMC and adipose tissue between rat and humans.

In Chapter 6 the results of the research project described in this thesis are evaluated. It was the aim of thesestudies to contribute to theimprovement ofthe risk and/or benefit assessment of SIF for humans, by using in vitro and in vivo animal and human models, and gene expression data in various animal and human tissues, as early biomarkers of effects of exposure to SIF. Although important information has been gathered on the metabolism and the estrogenic activity of SIF and their aglycones, we were not able to predict possible effects in human target tissues based on the results of changes in gene expression in target tissues obtained in the 8 weeks rat study. Possibly aged rats might be a more appropriate model than young ovariectomized rats.

RIKILT speurt naar gifstof die paarden doodt
Ramaker, R. ; Mol, J.G.J. - \ 2015
Resource: nieuwssite voor studenten en medewerkers van Wageningen UR 9 (2015)148. - ISSN 1389-7756 - p. 8 - 8.
paarden - diergezondheid - acer - toxische stoffen - gevaren - horses - animal health - toxic substances - hazards
Eten van esdoorns is soms dodelijk voor paarden. Rikilt onderzocht waar in Nederland de gevaren liggen.
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 - 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.
Innovative approaches to reduce animal testing : replace whenever possible, reduce through refinement and mechanistic understanding
Ravenzwaay, B. van - \ 2013
Wageningen : Wageningen University - ISBN 9789461736161 - 24
alternatieven voor dierproeven - dierproeven - in vitro - toxische stoffen - toxicologie - kinetica - modellen - dierenwelzijn - animal testing alternatives - animal experiments - toxic substances - toxicology - kinetics - models - animal welfare
'Many of the in vitro toxicological studies have not been sufficiently validated to determine their applicability domain, even less have gained regulatory acceptance. Major advantage of in vitro testing today is the early identification of significant hazards in compound development and reduced and targeted animal testing. Replacing complex animal tests may be achieved by a battery of in vitro test addressing the adverse outcome pathway in question. Kinetics models are needed to translate in vitro results into in vivo values.'
Microsphere-based binding assays for organic pollutants
Meimaridou, A. - \ 2013
Wageningen University. Promotor(en): Michel Nielen, co-promotor(en): Willem Haasnoot. - S.l. : s.n. - ISBN 9789461735768 - 139
persistente organische verontreinigende stoffen - toxische stoffen - vis - schildklierhormonen - doorstroomcytometrie - screenen - assays - persistent organic pollutants - toxic substances - fish - thyroid hormones - flow cytometry - screening

In this thesis the “proof of principle” of a preliminary “prototype kit” for the screening of dioxin-like PCBs, PBDEs and PAHs in fish combined with two different simplified generic cleanup procedures, according to the fish fat content, is presented. Toxicants such as the PCBs, PBDEs and PAHs and POPs mixtures (such as the technical mixtures of PCBs (Aroclors)) can be detected at relative low levels (with IC50 values 55±15, 2±0.4 and 4±0.5 ppb for the PCB77, PBDE47 and BaP, respectively) in fish samples in a multiplex, simple and inexpensive manner compared to existing techniques. The 3-plex immunoassay can be performed in two different detection platforms: the traditional flow cytometer- and the new imaging-based bead analyzers. The latter system offers a cheaper analysis and it is an easier transportable platform than the flow cytometer.

Presence of plant toxins in food and food
Dam, R.C.J. van; Madzora, B. ; Mol, J.G.J. ; Nijs, W.C.M. de - \ 2012
toxische stoffen - planten - toxinen - voedingsmiddelen - voedselsupplementen - voedselveiligheid - geneeskrachtige kruiden - toxic substances - plants - toxins - foods - food supplements - food safety - herbal drugs
The objective of this research is: investigate the occurrence of selected plant toxins in herbal products (food and food supplements) available on the Dutch market using a multi-plant toxin method based on LC-MS/MS.
A microbial fuel cell-based biosensor for the detection of toxic components in water
Stein, N.E. - \ 2011
Wageningen University. Promotor(en): Gerrit van Straten, co-promotor(en): Karel Keesman. - [S.l.] : S.n. - ISBN 9789461730275 - 176
biosensoren - microbiële brandstofcellen - toxische stoffen - waterverontreiniging - biosensors - microbial fuel cells - toxic substances - water pollution

In a microbial fuel cell bacteria produce electricity. When water with a constant quality is lead passed the bacteria, a constant current will be measured. When toxic components enter the cell with the water, the bacteria are affected and this will show as a decrease in current. In this way a microbial fuel cell can act as a sensor for toxic components in water. The research focused on the control of the sensor to reach a sensitive sensor. This was done by controlling the potential of the anode, on which the bacteria grow, using different methods and different values. Also it was found that by performing a dynamic type of measurement, a distinction could be made between different classes of components. Although sensitivity still has to be improved, a microbial fuel cell-based biosensor seems a promising technology in an early warning system detecting generic toxicity.

Residuen op groenten en fruit ter discussie
Woltering, E.J. - \ 2011
Voeding Nu 2011 (2011)1/2. - ISSN 1389-7608 - p. 18 - 19.
pesticidenresiduen - groenten - fruit - zuigelingenvoedsel - voedselveiligheid - voeding en gezondheid - toxische stoffen - pesticide residues - vegetables - infant foods - food safety - nutrition and health - toxic substances
De nVWA en het RIVM doen al jaren onderzoek naar residuen van giftige stoffen op groenten en fruit. Uit onderzoek blijkt dat met name peuters en baby’s meer groenten en fruit binnenkrijgen dan eerder werd gedacht. Met meer groenten en fruit zouden ze ook meer residuen binnenkrijgen. Ernst Woltering van Wageningen Universiteit plaatst het één en ander in perspectief.
IRMM HCB and HCBD in Blankvoorn (testmaterial for reference material)
Hoek-van Nieuwenhuizen, M. van - \ 2010
IJmuiden : IMARES (Report / IMARES Wageningen UR no. C113/10) - 7
waterkwaliteit - rutilus rutilus - monitoring - toxische stoffen - referentienormen - biologische monitoring - ecotoxicologie - visserij-ecologie - zeevisserij - kaderrichtlijn water - water quality - toxic substances - reference standards - biomonitoring - ecotoxicology - fisheries ecology - marine fisheries - water framework directive
Blankvoorn Nieuwe Merwede (Roach, Rutilus rultilus) has been tested as a reference material for the components HCBD and HCB for biota monitoring according to the Water Framework Directive. Both components in the blankvoorn are present at moderate levels (overall average levels of respectively HCBD 1.6 μg/kg and HCB 6.2 μg/kg). These concentrations are far above reporting limits (respectively 0.1 μg/kg for HCBD and 0.2 μg/kg for HCB) and should therefore be suitable for use in a reference material.
Dutch survey pyrrolizidine alkaloids in animal forage
Mulder, P.P.J. ; Beumer, B. ; Oosterink, J.E. ; Jong, J. de - \ 2009
Wageningen : Rikilt - Institute of Food Safety (Report / RIKILT , Institute of Food Safety 2009.018) - 45
ruwvoer (forage) - pyrrolizidinealkaloïden - voer - veevoeding - toxische stoffen - analytische methoden - nederland - forage - pyrrolizidine alkaloids - feeds - livestock feeding - toxic substances - analytical methods - netherlands
Pyrrolizidine alkaloids (PAs) are secondary plant metabolites produced by a number of plants from the Asteraceae (Compositae), Boriginaceae and Fabaceae (Leguminosae) families. Many of these alkaloids have been shown to be highly toxic, causing hepatic veno-occlusive disease (VOD), liver cirrhosis and ultimately death. PAs may have also mutagenic and carcinogenic potential. Amongst livestock, cattle and horses are especially susceptible to the toxic effects of the PAs. Humans may also be at risk by the consumption of milk of livestock fed with PA-contaminated forage. At RIKILT - Institute of Food Safety a (semi)quantitative method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of PAs in animal feeds has been developed and validated. This method comprises 40 macrocyclic PAs (including tertiary amines and N-oxides) representative for ragwort species. The method has been used for the analysis of 147 forage samples collected in 2006-2008.
The practicability of the integrated probabilistic risk assessment (IPRA) approach for substances in food
Bokkers, B.G.H. ; Bakker, M.I. ; Boon, P.E. ; Bos, P. ; Bosgra, S. ; Heijden, G.W.A.M. van der; Janer, G. ; Slob, W. ; Voet, H. van der - \ 2009
Bilthoven : RIVM (RIVM report 320121001/2009) - 79
risicoschatting - blootstelling - toxische stoffen - toxinen - gezondheidsbescherming - voedselveiligheid - voedselvergiftiging - extrapolatie - voeding en gezondheid - risk assessment - exposure - toxic substances - toxins - health protection - food safety - food poisoning - extrapolation - nutrition and health
In the Netherlands, the National Institute for Public Health and the Environment (RIVM) has successfully applied the IPRA approach to assess the human health risks of five substances in food. This method has been developed so that health risks can be described in more detail when a classical risk assessment has shown either that there is a risk or a risk cannot be excluded. In the present study, the risks of two mycotoxins (DON and T-2/HT-2), one heavy metal (cadmium), one group of pesticides (OPs), and one compound (acrylamide) which is formed during the heating of food containing high levels of starch are described
Trends in diet and exposure to chemicals in Dutch children
Boon, P.E. ; Asselt, E.D. van; Bakker, M.I. ; Kruizinga, A.G. ; Jansen, M.C.J.F. - \ 2009
Wageningen : RIKILT (Report / RIKILT 2009.002) - 47
voedselconsumptie - maaltijdpatronen - eetpatronen - kinderen - nederland - toxische stoffen - blootstelling - food consumption - meal patterns - eating patterns - children - netherlands - toxic substances - exposure
International sediment exchange for tests on organic contaminants
Eijgenraam, A. - \ 2009
Wageningen : Wageningen University, Environmental Science (Quarterly report / SETOC 2009.1) - 96
bodem - bodemchemie - bodemgiftigheid - toxische stoffen - bodemsamenstelling - bepaling - vochtgehalte - organische verbindingen - soil - soil chemistry - soil toxicity - toxic substances - soil composition - determination - moisture content - organic compounds
Exposure in surface waters for the aquatic risk assessment at EU level
Adriaanse, P.I. ; Leerdam, R.C. van; Boesten, J.J.T.I. - \ 2009
pesticiden - afvloeiingswater - oppervlaktewater - waterverontreiniging - uitspoelen - toxische stoffen - risicoschatting - milieu - scenario-analyse - pesticides - runoff water - surface water - water pollution - leaching - toxic substances - risk assessment - environment - scenario analysis
Poster presentation. In the FOCUS Surface Water Scenarios, an important entry route for plant protection products (PPP) into the water course is run-off from the adjacent field. Not much is known on the effect of run-off on the concentration in the FOCUS stream
Improved exposure assessment in Dutch ditches
Adriaanse, P.I. - \ 2009
hydrobiologie - ecosystemen - oppervlaktewater - drainage - drift - waterverontreiniging - sloten - uitspoelen - toxische stoffen - aquatische ecosystemen - kaderrichtlijn water - hydrobiology - ecosystems - surface water - water pollution - ditches - leaching - toxic substances - aquatic ecosystems - water framework directive
At present the exposure of the aquatic ecosystem to plant protection products is under-estimated in the Dutch registration procedure. Only spray drift is considered to be a relevant entry route in surface water. In reality drainage and surface run off may also be important routes. The EU registration procedure does take these routes into account. Construction of a Dutch ditch scenario with a 90th-percentile probability of occurrence exposure concentration, that considers the three relevant entry routes
Interpretation of the mitigation of runoff on the FOCUS Surface Water Scenarios as described in the FOCUS l&M report
Horst, M.M.S. ter; Adriaanse, P.I. ; Boesten, J.J.T.I. - \ 2009
Wageningen : Alterra (Alterra-rapport 1794) - 33
pesticiden - afvloeiingswater - oppervlaktewater - waterverontreiniging - risicoschatting - uitspoelen - toxische stoffen - milieu - scenario-analyse - pesticides - runoff water - surface water - water pollution - risk assessment - leaching - toxic substances - environment - scenario analysis
Our interpretation is that the reduced runoff fluxes (water and mass) of the 20 ha upstream are combined with the unchanged runoff water fluxes of the remaining 80 ha upstream catchment. This implies that the reduction factor on exposure concentrations in FOCUS streams of Step 4 FOCUS scenarios calculations compared to those of Step 3 calculations approximately equals the reduction factor applied on the runoff fluxes (water and mass of the 20 ha upstream).
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