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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    Multiclass screening in urine by comprehensive two-dimensional liquid chromatography time of flight mass spectrometry for residues of sulphonamides, beta-agonists and steroids
    Blokland, M.H. ; Zoontjes, P.W. ; Ginkel, L.A. van; Schans, M.G.M. van de; Sterk, S.S. ; Bovee, T.F.H. - \ 2018
    Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 35 (2018)9. - ISSN 1944-0049 - p. 1703 - 1715.
    Antibiotics - comprehensive 2D-LC - growth promoters - LC x LC - mass spectrometry - residues

    Nowadays routine residue monitoring involves the analysis of many compounds from different classes, mainly in urine. In the past two decades, developments heavily focused on the use of mass spectrometers (MS) and faster and more sensitive MS detectors have reached the market. However, chromatographic separation (CS) was rather ignored and the cognate developments in CS were not in line. As a result, residue analysis did not improve to the extent anticipated. CS by LC x LC is a promising technique and will enable a further increase in the range of compounds and compound classes that can be detected in a single run. In the present study, a self-built LC x LC system, using a 10 port valve, was connected to a single quadrupole MS with electrospray interface. Standards containing a mixture of sulphonamides, β-agonists and (steroid) hormones, 53 compounds, in total, were analysed. Results demonstrated that these compounds were well separated and could be detected at low levels in urine, i.e. limit of detection (LOD) from 1 µg L−1 for most β-agonists to 10 µg L−1 for some sulphonamides and most hormones. To enhance the sensitivity, optimisation was performed on an advanced commercial LC x LC system connected to a full scan accurate MS. This ultimately resulted in a fast high throughput untargeted method, including a simple sample clean-up in a 96-well format, for the analysis of urine samples.

    Risicobeoordeling van contaminanten in afval- en reststoffen bestemd voor gebruik als covergistingsmateriaal
    Ehlert, P.A.I. ; Wijnen, H.J. van; Struijs, J. ; Dijk, T.A. van; Schöll, L. van; Poorter, L.R.M. de - \ 2016
    Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-technical report 70) - 158
    biogas - co-vergisting - arsenicum - residuen - zware metalen - verontreinigende stoffen - pesticiden - biociden - mestbeleid - landbouwbeleid - organische verontreinigende stoffen - risicoschatting - biogas - co-fermentation - arsenic - residues - heavy metals - pollutants - pesticides - biocides - manure policy - agricultural policy - organic pollutants - risk assessment
    A number of wastes and by-products were reviewed for their suitability as substrates for co-digestion with animalmanure to produce biogas and a digestate for use as a fertiliser. The review included 21 substances proposed byLTO Noord (Dutch Farmers Union – Northern Netherlands) and Biogas Branche Organisatie (BBO, the Dutch BiogasIndustry Association) for inclusion in Annex Aa of the Fertiliser Act. At the request of the Ministry of EconomicAffairs a further 6 substances were added (21+6). In addition, 119 substances were re-reviewed in connection witha change to the reference composition for animal manure. The review focused on the possible adverseenvironmental effects of using the digestate as a fertiliser and followed the protocol for assessing the value andrisks of waste used as a fertiliser, version 2.1. The risk assessment included the inorganic contaminants (Cd, Cr, Cu,Hg, Ni, Pb, Zn, As) and organic contaminants (dioxine, PCBs, PAHs, mineral oil, residues of crop protectionproducts) as required by the Fertiliser Act. For all the wastes and by-products, data on composition were collectedfrom the literature and from analyses provided by stakeholders. Expert judgment was used where data were notavailable or were insufficient to conduct a risk assessment as prescribed by the protocol. Criteria for expertjudgment were developed for such situations. Two alternative risk assessment methods were developed for theresidues of pesticides and biocides, based partly on expert judgement. These methods were compared with themethod prescribed by the protocol. These three methods reflect different policy judgements; the protection level setby policymakers will determine which method should be used. The 21+6 substances were evaluated in accordancewith the protocol and using the three methods for evaluating the residues of pesticides and biocides. The resultswere compared with registered co-digestion materials in Flanders, Denmark and Germany. Recommendations aregiven to support policy decisions on the choice of alternative risk assessment method to be used to permit the codigestionof wastes and by-products in biogas production that produce an agronomically and environmentallyacceptable digestate for fertiliser use
    Distribution of chloramphenicol to tissues, plasma and urine in pigs after oral intake of low doses
    Aspenström-Fagerlund, Bitte ; Nordkvist, Erik ; Törnkvist, Anna ; Wallgren, Per ; Hoogenboom, Ron ; Berendsen, Bjorn ; Granelli, Kristina - \ 2016
    Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 33 (2016)9. - ISSN 1944-0049 - p. 1411 - 1420.
    Chloramphenicol - distribution - LC-MS/MS - pigs - residues

    Toxic effects of chloramphenicol in humans caused the ban for its use in food-producing animals in the EU. A minimum required performance level (MRPL) was specified for chloramphenicol at 0.3 μg kg–1 for various matrices, including urine. In 2012, residues of chloramphenicol were found in pig urine and muscle without signs of illegal use. Regarding its natural occurrence in straw, it was hypothesised that this might be the source, straw being compulsory for use as bedding material for pigs in Sweden. Therefore, we investigated if low daily doses of chloramphenicol (4, 40 and 400 μg/pig) given orally during 14 days could result in residues in pig tissues and urine. A dose-related increase of residues was found in muscle, plasma, kidney and urine (showing the highest levels), but no chloramphenicol was found in the liver. At the lowest dose, residues were below the MRPL in all tissues except in the urine. However, in the middle dose, residues were above the MRPL in all tissues except muscle, and at the highest dose in all matrices. This study proves that exposure of pigs to chloramphenicol in doses occurring naturally in straw could result in residues above the MRPL in plasma, kidney and especially urine.

    Eigen installatie, collectieve oplossingen of een mobiel systeem : naderende zuiveringsplicht dwingt telers tot keuzes
    Beerling, Ellen - \ 2016
    horticulture - greenhouse horticulture - water management - water treatment - agricultural research - standards - agricultural policy - residues - purification plants - cooperation - emission reduction

    Vanaf 1 januari 2018 moeten glastuinbouwbedrijven zuiveringstechnieken toepassen die restwater voor 95% kunnen zuiveren van gewasbeschermingsmiddelen. Telers hebben daarbij de mogelijkheid om een eigen installatie, een collectieve oplossingen of een mobiel systeem toe te passen dat het restwater op afroep komt zuiveren. Ellen Beerling en Daan van Empel belichten de staat van onderzoek en beleid.

    Determination of Glyphosate Levels in Breast Milk Samples from Germany by LC-MS/MS and GC-MS/MS
    Steinborn, Angelika ; Alder, Lutz ; Michalski, Britta ; Zomer, Paul ; Bendig, Paul ; Martinez, Sandra Aleson ; Mol, Hans G.J. ; Class, Thomas J. ; Costa Pinheiro, Nathalie - \ 2016
    Journal of Agricultural and Food Chemistry 64 (2016)6. - ISSN 0021-8561 - p. 1414 - 1421.
    breast milk - GC-MS/MS - glyphosate - LC-MS/MS - residues

    This study describes the validation and application of two independent analytical methods for the determination of glyphosate in breast milk. They are based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS), respectively. For LC-MS/MS, sample preparation involved an ultrafiltration followed by chromatography on an anion exchange column. The analysis by GC-MS/MS involved an extraction step, cleanup on a cation exchange column, and derivatization with heptafluorobutanol and trifluoroacetic acid anhydride. Both methods were newly developed for breast milk and are able to quantify glyphosate residues at concentrations as low as 1 ng/mL. The methods were applied to quantify glyphosate levels in 114 breast milk samples, which had been collected from August to September of 2015 in Germany. The mothers participated at their own request and thus do not form a representative sample. In none of the investigated samples were glyphosate residues above the limit of detection found.

    Concentrations of dioxins and dioxine-like PCBs in feed material in the Netherlands, 2001-11
    Adamse, P. ; Fels-Klerx, H.J. van der; Schoss, S. ; Jong, J. de; Hoogenboom, L.A.P. - \ 2015
    Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 32 (2015)8. - ISSN 1944-0049 - p. 1301 - 1311.
    toxic equivalency factors - contaminated feed - milk - food - fat - residues - pcdfs - pcdds - eggs
    This study aimed to obtain insights into contamination of feed materials used in the Netherlands with dioxins (polychlorinated dibenzo-p-dioxins and dibenzofurans) and dioxin-like polychlorinated biphenyls (PCBs). Monitoring results from the period 2001-11, covering in total 4938 samples, were statistically analysed and evaluated against the statutory limits set at the beginning or during this period. The percentage of samples exceeding maximum levels set within the European Union for either dioxins or the sum of dioxins and dioxin-like PCBs were below 1% for most feed categories, except for fish meal (4.1%), clay minerals (binders and anti-caking agents) (3.4%), and vegetable oils and byproducts (1.7%). For most feed categories, non-compliance with the action threshold (roughly 33% lower than maximum levels) for either dioxins or dioxin-like PCBs was up to three times higher than non-compliance with the respective maximum levels. Exceedance of action thresholds was just above 1% for animal fat, pre-mixtures and feed materials of plant origin excluding vegetable oils. For the categories fish meal, clay minerals, and vegetable oils and byproducts, the action thresholds were exceeded by 5.0%, 9.8% and 3.0% of the samples, respectively. In general, the percentages of samples that exceeded the action thresholds and maximum levels were lower than those reported for the European Union by the European Food Safety Authority (EFSA). In most of the feed materials, there seems to be a decreasing trend in concentrations of dioxins or dioxin-like PCBs over the years. However, a lowering of the limits of quantification during this period and the low concentrations in most samples precludes drawing strong conclusions.
    Removal of micropollutants in source separated sanitation
    Butkovskyi, A. - \ 2015
    Wageningen University. Promotor(en): Huub Rijnaarts; Grietje Zeeman, co-promotor(en): L. Hernández Leal. - Wageningen : Wageningen University - ISBN 9789462574168 - 189
    verontreinigende stoffen - verontreiniging - waterverontreiniging - afvalwater - stedelijk afvalwater - volksgezondheidsbevordering - waterzuivering - verwijdering - geneesmiddelen - farmaceutische producten - antibioticumresiduen - residuen - pollutants - pollution - water pollution - waste water - municipal wastewater - sanitation - water treatment - removal - drugs - pharmaceutical products - antibiotic residues - residues
    Source separated sanitation is an innovative sanitation method designed for minimizing use of energy and clean drinking water, and maximizing reuse of water, organics and nutrients from waste water. This approach is based on separate collection and treatment of toilet wastewater (black water) and the rest of the domestic wastewater (grey water). Different characteristics of wastewater streams facilitate recovery of energy, nutrients and fresh water. To ensure agricultural or ecological reuse of liquid and solid products of source separated sanitation, the quality of these materials has to meet (future) standards, i.e. for micropollutant concentrations. Therefore the objectives of this thesis included assessment of micropollutant content of source separated sanitation products intended for resource recovery and examination of post-treatment technologies for micropollutant mitigation within source separated sanitation
    The assessment of selectivity in different quadrupole-orbitrap mass spectrometry acquisition
    Berendsen, B.J.A. ; Wegh, R.S. ; Meijer, T. ; Nielen, M.W.F. - \ 2015
    Journal of the American Society for Mass Spectrometry 26 (2015)2. - ISSN 1044-0305 - p. 337 - 346.
    performance liquid-chromatography - veterinary drugs - confirmation - metabolites - residues - plasma - food - meat
    Selectivity of the confirmation of identity in liquid chromatography (tandem) mass spectrometry using Q-Orbitrap instrumentation was assessed using different acquisition modes based on a representative experimental data set constructed from 108 samples, including six different matrix extracts and containing over 100 analytes each. Single stage full scan, all ion fragmentation, and product ion scanning were applied. By generating reconstructed ion chromatograms using unit mass window in targeted MS(2), selected reaction monitoring (SRM), regularly applied using triple-quadrupole instruments, was mimicked. This facilitated the comparison of single stage full scan, all ion fragmentation, (mimicked) SRM, and product ion scanning applying a mass window down to 1 ppm. Single factor Analysis of Variance was carried out on the variance (s(2)) of the mass error to determine which factors and interactions are significant parameters with respect to selectivity. We conclude that selectivity is related to the target compound (mainly the mass defect), the matrix, sample clean-up, concentration, and mass resolution. Selectivity of the different instrumental configurations was quantified by counting the number of interfering peaks observed in the chromatograms. We conclude that precursor ion selection significantly contributes to selectivity: monitoring of a single product ion at high mass accuracy with a 1 Da precursor ion window proved to be equally selective or better to monitoring two transition products in mimicked SRM. In contrast, monitoring a single fragment in all ion fragmentation mode results in significantly lower selectivity versus mimicked SRM. After a thorough inter-laboratory evaluation study, the results of this study can be used for a critical reassessment of the current identification points system and contribute to the next generation of evidence-based and robust performance criteria in residue analysis and sports doping.
    EUBerry – verhoging van duurzaamheid en consumptie kleinfruit : samenvatting activiteiten DLO Wageningen UR : PT Eindrapport EUBerry 2011-2014
    Kruistum, G. van; Evenhuis, A. ; Groot, M.J. ; Roelofs, P.F.M.M. ; Sijtsema, S.J. ; Zimmermann, K.L. - \ 2015
    Lelystad : Praktijkonderzoek Plant & Omgeving, Business Unit PPO-agv - 31
    europese unie - kleinfruit - geïntegreerde bestrijding - residuen - teeltsystemen - voeding en gezondheid - consumptie - gewaskwaliteit - aardbeien - duurzaamheid (sustainability) - marketing - european union - small fruits - integrated control - residues - cropping systems - nutrition and health - consumption - crop quality - strawberries - sustainability - marketing
    Doel van dit EU-project is de bevordering van de consumptie van kwalitatief hoogwaardig vers kleinfruit door geïntegreerde gewasbescherming en residuarme teelt, verbeterde teelttechnieken en aandacht voor gezondheidsaspecten.
    The MCRA model for probabilistic single-compound and cumulative risk assessment of pesticides
    Voet, H. van der; Boer, W.J. de; Kruisselbrink, J.W. ; Goedhart, P.W. ; Heijden, G.W.A.M. van der; Kennedy, M.C. ; Boon, P.E. ; Klaveren, J.D. van - \ 2015
    Food and Chemical Toxicology 79 (2015). - ISSN 0278-6915 - p. 5 - 12.
    dietary exposure - carbamate insecticides - 21st-century roadmap - chemicals - food - organophosphorus - framework - residues - project
    Pesticide risk assessment is hampered by worst-case assumptions leading to overly pessimistic assessments. On the other hand, cumulative health effects of similar pesticides are often not taken into account. This paper describes models and a web-based software system developed in the European research project ACROPOLIS. The models are appropriate for both acute and chronic exposure assessments of single compounds and of multiple compounds in cumulative assessment groups. The software system MCRA (Monte Carlo Risk Assessment) is available for stakeholders in pesticide risk assessment at We describe the MCRA implementation of the methods as advised in the 2012 EFSA Guidance on probabilistic modelling, as well as more refined methods developed in the ACROPOLIS project. The emphasis is on cumulative assessments. Two approaches, sample-based and compound-based, are contrasted. It is shown that additional data on agricultural use of pesticides may give more realistic risk assessments. Examples are given of model and software validation of acute and chronic assessments, using both simulated data and comparisons against the previous release of MCRA and against the standard software DEEM-FCID used by the Environmental Protection Agency in the USA. It is shown that the EFSA Guidance pessimistic model may not always give an appropriate modelling of exposure.
    Structural and functional response of the soil bacterial community to application of manure from difloxacin-treated pigs
    Jechalke, S. ; Focks, A. ; Rosendahl, I. ; Groeneweg, J. ; Siemens, J. ; Heuer, H. ; Smalla, K. - \ 2014
    FEMS microbiology ecology 87 (2014)1. - ISSN 0168-6496 - p. 78 - 88.
    mediated quinolone resistance - antibiotic-resistance - sulfadiazine - genes - plasmid - fate - rhizosphere - evolution - integrons - residues
    Difloxacin (DIF) belongs to the class of fluoroquinolone antibiotics that have been intensively used for the treatment of bacterial infections in veterinary and human medicine. The aim of this field study was to compare the effect of manure from DIF-treated pigs and untreated pigs on the bacterial community structure and resistance gene abundance in bulk soil and rhizosphere of maize. A significant effect of DIF manure on the bacterial community composition in bulk soil was revealed by denaturing gradient gel electrophoresis (DGGE) of bacterial 16S rRNA gene fragments amplified from total community DNA. In few samples, quinolone resistance genes qnrB and qnrS1/qnrS2 were detected by PCR and subsequent hybridization, while qnrA was not detected. Quantitative PCR revealed an increased abundance of the integrase gene intI1 of class I integrons and sulfonamide resistance genes sul1 and sul2 in DIF manure-treated bulk soil and rhizosphere, relative to 16S rRNA genes, while traN genes specific for LowGC-type plasmids were increased only in bulk soil. Principal component analysis of DGGE profiles suggested a manure effect in soil until day 28, but samples of days 71 and 140 were found close to untreated soil, indicating resilience of soil community compositions from disturbances by manure.
    Levels of Organochlorine Pesticides in Blood Plasma from Residents of Malaria-Endemic Communities in Chiapas, Mexico
    Ruiz-Suarez, L.E. ; Castro-Chan, R.A. ; Rivero-Perez, N.E. ; Trejo-Acevedo, A. ; Guillen-Navarro, G.K. ; Geissen, V. ; Bello-Mendoza, R. - \ 2014
    International Journal of Environmental Research and Public Health 11 (2014)10. - ISSN 1660-4601 - p. 10444 - 10460.
    southern mexico - exposure - serum - ddt - pollutants - children - samples - women - inhabitants - residues
    Organochlorine (OC) pesticides have been extensively used for pest control in agriculture and against malaria vectors in the region of Soconusco, Chiapas, in southern Mexico. Our study aimed to identify whether the inhabitants of four Soconusco communities at different locations (i.e., altitudes) and with different history of use of OC pesticides, have been similarly exposed to residues of these pesticides. In particular, we analyzed the potential relationship between levels of OC pesticides in plasma and the age, gender, and residence of the study population (n = 60). We detected seven pesticides in total (gamma-HCH, beta-HCH, heptachlor, p,p'-DDE, p,p'-DDT, beta-endosulfan, endrin aldehyde). Of these, p,p'-DDE and beta-endosulfan were the most frequently found (in 98% and 38% of the samples, respectively). The low-altitude (60 years) had the highest p,p'-DDE level (56.94 +/- 57.81 mu g/L) of all age groups, while men had higher p,p'-DDE (34.00 +/- 46.76 mu g/L) than women. Our results demonstrate that residents of the Soconusco region are exposed to p,p'-DDE because of high exposure to DDT in the past and current environmental exposure to this DDT-breakdown product.
    Biorefining of wheat straw using an acetic and formic acid based organosolv fractionation process
    Snelders, J. ; Dornez, E. ; Benjelloun-Mlayah, B. ; Huijgen, W.J.J. ; Wild, P.J. de; Gosselink, R.J.A. ; Gerritsma, J. ; Courtin, C.M. - \ 2014
    Bioresource Technology 156 (2014). - ISSN 0960-8524 - p. 275 - 282.
    xylan-degrading enzymes - enzymatic-hydrolysis - lignocellulosic biomass - pretreatment - lignin - fermentation - residues - hemicellulose - bioethanol - cellulose
    To assess the potential of acetic and formic acid organosolv fractionation of wheat straw as basis of an integral biorefinery concept, detailed knowledge on yield, composition and purity of the obtained streams is needed. Therefore, the process was performed, all fractions extensively characterized and the mass balance studied. Cellulose pulp yield was 48% of straw dry matter, while it was 21% and 27% for the lignin and hemicellulose-rich fractions. Composition analysis showed that 67% of wheat straw xylan and 96% of lignin were solubilized during the process, resulting in cellulose pulp of 63% purity, containing 93% of wheat straw cellulose. The isolated lignin fraction contained 84% of initial lignin and had a purity of 78%. A good part of wheat straw xylan (58%) ended up in the hemicellulose-rich fraction, half of it as monomeric xylose, together with proteins (44%), minerals (69%) and noticeable amounts of acids used during processing.
    Impact of crop-manure ratios on energy production and fertilizing characteristics of liquid and solid digestate during codigestion
    Pabon Pereira, C.P. ; Vries, J.W. de; Slingerland, M.A. ; Zeeman, G. ; Lier, J.B. van - \ 2014
    Environmental Technology 35 (2014)19. - ISSN 0959-3330 - p. 2427 - 2434.
    anaerobic co-digestion - methane production - biogas production - cattle manure - grass-silage - pig manure - maize - residues - sludge - slurry
    The influence of maize silage-manure ratios on energy output and digestate characteristics was studied using batch experiments. The methane production, nutrients availability (N and P) and heavy metals' content were followed in multiflask experiments at digestion times 7, 14, 20, 30 and 60 days. In addition, the available nutrient content in the liquid and solid parts of the digestate was evaluated. Aanaerobic digestion favoured the availability of nutrients to plants, after 61 days 20-26% increase in NH4+ and 0-36% increase in PO43- were found in relation to initial concentrations. Digestion time and maize addition increased the availability of PO43-. Inorganic nutrients were found to be mainly available in the liquid part of the digestate, i.e. 80-92% NH4+ and 65-74% PO43-. Manure had a positive effect on the methane production rate, whereas maize silage increased the total methane production per unit volatile solids in all treatments.
    Pesticide risk production pogramme : feasibility study of the proposed pesticide registration and post-registration processes
    Bremmer, J. ; Dhuga Chaka, K. ; Dijkxhoorn, Y. ; Mammo, B. - \ 2014
    Den Haag : LEI Wageningen UR (Memorandum / LEI 14-109) - 41
    gewasbescherming - chemische bestrijding - milieueffect - ethiopië - residuen - richtlijnen (guidelines) - haalbaarheidsstudies - registratie - tuinbouwgewassen - risicoanalyse - volksgezondheid - pesticiden - plant protection - chemical control - environmental impact - ethiopia - residues - guidelines - feasibility studies - registration - horticultural crops - risk analysis - public health - pesticides
    Report on developing guidelines and procedures for the pesticide registration in Ethiopia in a scientifically underpinned way and as specific as possible for Ethiopian conditions. It covers the aspects of efficacy assessment, human health risk assessment as well as environmental risk assessment. It aims to develop the capacity at the APHRD to apply these guidelines and procedures. The Work package will result in an evaluation manual plus software tool for the Animal and Plant Health Regulatory Directorate (APHRD) of the Ministry of Agriculture of Ethiopia. The user-friendly software tool operationalises the guidelines and procedures for human health risk assessment and environmental risk assessment; all basic pesticide data can be entered in it and these will be used for the risk estimates.
    Sclerotium rolfsii dynamics in soil as affected by crop sequences
    Leoni, C. ; Braak, C.J.F. ter; Gilsanz, J.C. ; Dogliotti, S. ; Rossing, W.A.H. ; Bruggen, A.H.C. van - \ 2014
    Applied Soil Ecology 75 (2014). - ISSN 0929-1393 - p. 95 - 105.
    southern blight - vegetable farms - soilborne pathogens - population-dynamics - organic amendments - north-carolina - management - rotations - survival - residues
    Crop rotation has been used for the management of soilborne diseases for centuries, but has not often been planned based on scientific knowledge. Our objective was to generate information on Sclerotium rolfsii dynamics under different crop or intercrop activities, and design and test a research approach where simple experiments and the use of models are combined to explore crop sequences that minimize Southern blight incidence. The effect of seventeen green manure (GM) amendments on sclerotia dynamics was analyzed in greenhouse and field plot experiments during two years. The relative densities of viable sclerotia 90 days after winter GM (WGM) incorporation were generally lower than after summer GM (SGM) incorporation, with average recovery values of 60% and 61% for WGM in the field, 66% and 43% for WGM in the greenhouse, and 162% to 91% for SGM in the greenhouse, in 2009 and 2010, respectively. Sclerotia survival on day d after GM amendment was described by the model Sf = Si × exp(-b × d), relating initial (Si) and final (Sf) sclerotia densities. Relative decay rates of the sclerotia (b) in SGM amended soil were largest for alfalfa (0.0077 ± 0.0031 day-1) and sudangrass (0.0072 ± 0.0030 day-1). In WGM amended soil, the largest b values were for oat (0.0096 ± 0.0024 day-1), wheat (0.0090 ± 0.0024 day-1) and alfalfa (0.0087 ± 0.0023 day-1). The effect of three cropping sequences (sweet pepper–fallow, sweet pepper–black oat and sweet pepper–onion) on sclerotia dynamics was analyzed in microplot experiments, and the data were used to calibrate the model Pf = Pi/(a + ßPi), relating initial (Pi) and final (Pf) sclerotia densities. Median values for the relative rate of population increase at low Pi (1/a, dimension less) and the asymptote (1/ß, number of viable sclerotia in 100 g of dry soil) were 8.22 and 4.17 for black oat (BO), 1.13 and 8.64 for onion (O), and 6.26 and 17.93 for sweet pepper (SwP). By concatenating the two models, sclerotia population dynamics under several crop sequences were simulated. At steady state, the sequence SwP–O–Fallow–BO resulted in the lowest long-term sclerotia density (7.09 sclerotia/100 g soil), and SwP–Fallow in the highest (17.89 sclerotia/100 g soil). The developed methodology facilitates the selection of a limited number of rotation options to be tested in farmers’ fields.
    Mechanisms contributing to the thermal analysis of waste incineration bottom ash and quantification of idfferent carbon species
    Rocca, S. ; Zomeren, A. van; Costa, G. ; Dijkstra, J.J. ; Comans, R.N.J. ; Lombardi, F. - \ 2013
    Waste Management 33 (2013)2. - ISSN 0956-053X - p. 373 - 381.
    loss-on-ignition - fly-ash - unburned carbon - behavior - speciation - residues - coal
    The focus of this study was to identify the main compounds affecting the weight changes of bottom ash (BA) in conventional loss on ignition (LOI) tests and to obtain a better understanding of the individual processes in heterogeneous (waste) materials such as BA. Evaluations were performed on BA samples from a refuse derived fuel incineration (RDF-I) plant and a hospital waste incineration (HW-I) plant using thermogravimetric analysis and subsequent mass spectrometry (TG–MS) analysis of the gaseous thermal decomposition products. Results of TG–MS analysis on RDF-I BA indicated that the LOI measured at 550 °C was due to moisture evaporation and dehydration of Ca(OH)2 and hydrocalumite. Results for the HW-I BA showed that LOI at 550 °C was predominantly related to the elemental carbon (EC) content of the sample. Decomposition of CaCO3 around 700 °C was identified in both materials. In addition, we have identified reaction mechanisms that underestimate the EC and overestimate the CaCO3 contents of the HW-I BA during TG–MS analyses. These types of artefacts are expected to occur also when conventional LOI methods are adopted, in particular for materials that contain CaO/Ca(OH)2 in combination with EC and/or organic carbon, such as e.g. municipal solid waste incineration (MSWI) bottom and fly ashes. We suggest that the same mechanisms that we have found (i.e. in situ carbonation) can also occur during combustion of the waste in the incinerator (between 450 and 650 °C) demonstrating that the presence of carbonate in bottom ash is not necessarily indicative for weathering. These results may also give direction to further optimization of waste incineration technologies with regard to stimulating in situ carbonation during incineration and subsequent potential improvement of the leaching behavior of bottom ash.
    Short-term extractability of sulfadiazine after application to soils
    Müller, T. ; Rosendahl, I. ; Focks, A. ; Siemens, J. ; Klasmeier, J. ; Matthies, M. - \ 2013
    Environmental Pollution 172 (2013). - ISSN 0269-7491 - p. 180 - 185.
    sulfonamide antibiotics - test-plot - manure - residues - fate - bioavailability - environment - extraction - transport - pathways
    The long-term environmental fate of the veterinary antibiotic sulfadiazine (SDZ) in soils is determined by a reversible sequestration into a residual fraction and an irreversible formation of non-extractable residues (NER), which can be described as first-order rate processes. However, the concentration dynamics of the resulting fractions of SDZ in soil show an unexplained rapid reduction of extractability during the first 24 h. We therefore investigated the short-term extractability of SDZ in two different soils under different SDZ application procedures over 24 h: with and without manure, for air-dried and for moist soils. In all batches, we observed an instantaneous loss of extractability on a time scale of minutes as well as kinetically determined sequestration and NER formation over 24 h. Data evaluation with a simple kinetic model led to the conclusion that application with manure accelerated the short-term formation of NER, whereas sequestration was very similar for all batches.
    Strategieën voor residuvermindering bij houtig kleinfruit (rode bes) : tussenrapportage - ersultaten 2012
    Wenneker, M. ; Steeg, P.A.H. van der - \ 2013
    Randwijk : Praktijkonderzoek Plant en Omgeving, Bloembollen, Boomkwekerij & Fruit (Rapport 2013-15) - 17
    fruitteelt - kleinfruit - bessen - residuen - resteffecten - kwaliteit na de oogst - vruchtrot - ziektebestrijding - behandeling - reductie - ribes rubrum - rode aalbessen - fungiciden - fruit growing - small fruits - berries - residues - residual effects - postharvest quality - fruit rots - disease control - treatment - reduction - ribes rubrum - red currants - fungicides
    Doel van het onderzoek is het opzetten en testen van strategieën om het aantal verschillende residuen en de residu gehaltes op rode bes te verminderen. Het onderzoek is gericht op de teelt van rode bessen voor de lange bewaring. In overleg met de telers worden verschillende strategieën opgesteld. Deze strategieën worden getest ten opzichte van het praktijkschema van de teler. Bij de pluk worden de residu-gehaltes van de vruchten bij de verschillende strategieën bepaald. Van de verschillende behandelingen (strategieën) wordt het effect op de bewaarkwaliteit bepaald (lange bewaring).
    Use of veterinary medicijnes, feed additives and probiotics in four major internationally traded aquaculture species farmed in Asia
    Rico, A. ; Tran, M. ; Satopornvanit, K. ; Jiang, M. ; Shahabiddin, A.M. ; Henriksson, P.J.G. ; Brink, P.J. van den - \ 2013
    Aquaculture 412-413 (2013). - ISSN 0044-8486 - p. 231 - 243.
    pangasianodon-hypophthalmus - mangrove areas - human health - residues - vietnam - risks - water
    Antimicrobials, parasiticides, feed additives and probiotics are used in Asian aquaculture to improve the health status of the cultured organisms and to prevent or treat disease outbreaks. Detailed information on the use of such chemicals in Asian aquaculture is limited, but of crucial importance for the evaluation of their potential human health and environmental risks. This study reports the outcomes of a survey on the use of chemical and biological products in 252 grow-out aquaculture farms and 56 farm supply shops in four countries in Asia. The survey was conducted between 2011 and 2012, and included nine aquaculture farm groups: Penaeid shrimp farms in Bangladesh, China, Thailand and Vietnam; Macrobrachium prawn farms, and farms producing both Penaeid shrimps and Macrobrachium prawns in Bangladesh; tilapia farms in China and Thailand; and Pangasius catfish farms in Vietnam. Results were analysed with regard to the frequencies of use of active ingredients and chemical classes, reported dosages, and calculated applied mass relative to production. A range of farm management and farm characteristics were used as independent variables to explain observed chemical use patterns reported by farmers within each group. Sixty different veterinary medicinal ingredients were recorded (26 antibiotics, 19 disinfectants, and 15 parasiticides). The use of antibiotic treatments was found to be significantly higher in the Vietnamese Pangasius farms. However, total quantities of antibiotics, relative to production, applied by the Pangasius farmers were comparable or even lower than those reported for other animal production commodities. Semi-intensive and intensive shrimp farms in China, Thailand and Vietnam showed a decrease in the use of antibiotic treatments. These farm groups utilised the largest amount of chemicals relative to production, with feed additives and plant extracts, probiotics, and disinfectants, being the most used chemical classes, mainly for disease prevention. The surveyed farmers generally did not exceed recommended dosages of veterinary medicines, and nationally or internationally banned compounds were (with one exception) reported neither by the surveyed farmers, nor by the surveyed chemical sellers. Factors underlying the observed differences in chemical use patterns differed widely amongst farm groups, and geographical location was found to be the only factor influencing chemical ingredient application patterns in the majority of the studied farm groups.
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