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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Aflatoxin B1 in nixtamalized maize in Mexico; occurrence and accompanying risk assessment
Gilbert Sandoval, Ixchel ; Wesseling, Sebastiaan ; Rietjens, Ivonne M.C.M. - \ 2019
Toxicology Reports 6 (2019). - ISSN 2214-7500 - p. 1135 - 1142.
Aflatoxin B1 - Liver cancer - Maize - Margin of exposure (MOE) - Mexico - Risk assessment

Maize is a staple food in Mexico that might contain Aflatoxin B1 (AFB1). Nonetheless, data on the exposure and risk assessment of AFB1 from maize for the Mexican population are limited. The aim of the present study was to analyse the occurrence of AFB1 in Mexican nixtamalized maize samples, and to assess the accompanying exposure and risk. Four out of 88 samples contained AFB1 at levels above the limit of detection (1 ng/g). AFB1 occurrence values obtained in this study and additional occurrence values from literature were combined with available literature data for mean and P95 consumption of maize based products. For a 70 kg body weight person, lower bound and upper bound exposure assessments resulted in estimated daily intakes (EDI) of 0.7–8.5 ng/kg bw/day, based on a mean maize consumption. Based on the P95 maize consumption these EDI values amounted to 3.3–11.7 ng/kg bw/day. The corresponding Margin of Exposure (MOE) values amounted to 257-20 for the mean and 50-15 for the P95 consumers. The estimated increased cancer risks were 9-320 and 43-439 cases/106 individuals/lifetime of 75 years for the mean and P95 consumers, respectively. Altogether, the assessment reveals the need for continued risk management of AFB1 in Mexico.

Can multi-use of the sea be safe? A framework for risk assessment of multi-use at sea
Hoof, L. van; Burg, S.W.K. van den; Banach, J.L. ; Röckmann, C. ; Goossen, M. - \ 2019
Ocean & Coastal Management (2019). - ISSN 0964-5691
Multi-use at sea - Risk assessment - Risk governance - Seaweed production - Wind farms

By 2050 the world population is expected to reach 10 billion people. This population needs food, water and energy. Increasingly, opportunities are sought out at sea to accommodate these needs. As there is already competition for space, especially in the near-shore, opportunities for multi-use, including the combination of, for example, food and energy production in a single location, are sought. One issue that needs to be addressed to allow for multi-use at sea is safety. Existing frameworks for (marine) risk assessment tend to be rather sector specific and, although existing models and frameworks for risk analysis provide useful elements for an integrated analysis, none of the approaches fully caters for the need of having a framework based on a cyclical process of stakeholder input in all steps of the process of risk identification, risk management and risk evaluation and communication, identifying actions to be taken and providing tools useful in each of the steps, while integrating the three perspectives of maritime safety, food (and feed) safety, and environmental impact assessment and the different perspectives of the actors involved. This study developed a common framework for the risk assessment of multi-use at sea, consisting of six steps (Exploring, Understanding, Appraising, Deciding, Implementing and Evaluating & Communication). The framework encompasses and integrates an analysis of food and feed safety aspects, the safety of people and equipment, and environmental safety aspects. For each step, actions are defined, tools that can be of help to stakeholders are presented, and stakeholder participation measures are described. The framework is iterative and dynamic in its nature; with constant communication and evaluation of progress, decisions can be taken to either take a step forward or back. The framework is developed to assist operators and producers, policymakers, and other stakeholders in assessing and managing risks of multi-use at sea.

Multi-host disease management: The why and the how to include wildlife
Portier, Julien ; Ryser-Degiorgis, Marie Pierre ; Hutchings, Mike R. ; Monchâtre-Leroy, Elodie ; Richomme, Céline ; Larrat, Sylvain ; Poel, Wim H.M. Van Der; Dominguez, Morgane ; Linden, Annick ; Santos, Patricia Tavares ; Warns-Petit, Eva ; Chollet, Jean Yves ; Cavalerie, Lisa ; Grandmontagne, Claude ; Boadella, Mariana ; Bonbon, Etienne ; Artois, Marc - \ 2019
BMC Veterinary Research 15 (2019)1. - ISSN 1746-6148
Coordination - Decision-making framework - Emerging infectious diseases - Europe - Integrated management - Policy making - Proportionate management - Risk assessment - Wildlife - Zoonosis

In recent years, outbreaks caused by multi-host pathogens (MHP) have posed a serious challenge to public and animal health authorities. The frequent implication of wildlife in such disease systems and a lack of guidelines for mitigating these diseases within wild animal populations partially explain why the outbreaks are particularly challenging. To face these challenges, the French Ministry of Agriculture launched a multi-disciplinary group of experts that set out to discuss the main wildlife specific concepts in the management of MHP disease outbreaks and how to integrate wildlife in the disease management process. This position paper structures the primary specific concepts of wildlife disease management, as identified by the working group. It is designed to lay out these concepts for a wide audience of public and/or animal health officers who are not necessarily familiar with wildlife diseases. The group's discussions generated a possible roadmap for the management of MHP diseases. This roadmap is presented as a cycle for which the main successive step are: step 1-descriptive studies and monitoring; step 2-risk assessment; step 3-management goals; step 4-management actions and step 5-assessment of the management plan. In order to help choose the most adapted management actions for all involved epidemiological units, we integrated a decision-making framework (presented as a spreadsheet). This tool and the corresponding guidelines for disease management are designed to be used by public and health authorities when facing MHP disease outbreaks. These proposals are meant as an initial step towards a harmonized transboundary outbreak response framework that integrates current scientific understanding adapted to practical intervention.

Mode of action of microbial biological control agents against plant diseases: Relevance beyond efficacy
Köhl, Jürgen ; Kolnaar, Rogier ; Ravensberg, Willem J. - \ 2019
Frontiers in Plant Science 10 (2019). - ISSN 1664-462X
Antagonist - Biological control - Mode of action - Plant diseases - Risk assessment - Screening

Microbial biological control agents (MBCAs) are applied to crops for biological control of plant pathogens where they act via a range of modes of action. Some MBCAs interact with plants by inducing resistance or priming plants without any direct interaction with the targeted pathogen. Other MBCAs act via nutrient competition or other mechanisms modulating the growth conditions for the pathogen. Antagonists acting through hyperparasitism and antibiosis are directly interfering with the pathogen. Such interactions are highly regulated cascades of metabolic events, often combining different modes of action. Compounds involved such as signaling compounds, enzymes and other interfering metabolites are produced in situ at low concentrations during interaction. The potential of microorganisms to produce such a compound in vitro does not necessarily correlate with their in situ antagonism. Understanding the mode of action of MBCAs is essential to achieve optimum disease control. Also understanding the mode of action is important to be able to characterize possible risks for humans or the environment and risks for resistance development against the MBCA. Preferences for certain modes of action for an envisaged application of a MBCA also have impact on the screening methods used to select new microbials. Screening of MBCAs in bioassays on plants or plant tissues has the advantage that MBCAs with multiple modes of action and their combinations potentially can be detected whereas simplified assays on nutrient media strongly bias the selection toward in vitro production of antimicrobial metabolites which may not be responsible for in situ antagonism. Risks assessments for MBCAs are relevant if they contain antimicrobial metabolites at effective concentration in the product. However, in most cases antimicrobial metabolites are produced by antagonists directly on the spot where the targeted organism is harmful. Such ubiquitous metabolites involved in natural, complex, highly regulated interactions between microbial cells and/or plants are not relevant for risk assessments. Currently, risks of microbial metabolites involved in antagonistic modes of action are often assessed similar to assessments of single molecule fungicides. The nature of the mode of action of antagonists requires a rethinking of data requirements for the registration of MBCAs.

Stepwise screening of candidate antagonists for biological control of Blumeria graminis f. sp. tritici
Köhl, Jürgen ; Goossen van de Geijn, Helen ; Groenenboom de Haas, Lia ; Henken, Betty ; Hauschild, Rüdiger ; Hilscher, Ulrike ; Lombaers-van der Plas, Carin ; Bosch, Trudy van den; Wikström, Mariann - \ 2019
Biological Control 136 (2019). - ISSN 1049-9644
Antagonists - Biological control - Blumeria graminis f. sp. tritici - Powdery mildew - Risk assessment - Screening criteria - Tilletiospsis pallescens - Wheat

Antagonists for the biological control of Blumeria graminis f. sp. tritici were selected using a stepwise screening approach. Fungal colonizers of powdery mildew pustules were isolated from leaves of cereals and other plant species. Spore production, cold tolerance, drought tolerance and UV-B resistance as important characteristics for application of biocontrol candidates in the phyllosphere were tested in in vitro assays and preliminary risk assessments were conducted. Amongst 850 tested isolates 58% belonged to various taxonomical groups of Cladosporium. Only 3% belonged to species that have been reported in literature as antagonistic to powdery mildews. The stepwise screening approach allowed to reduce the number of candidate antagonists using screening criteria that can be tested reliably and cost-effectively in in vitro assays and by data mining from initially 1237 isolates down to 143 candidate antagonists belonging to 42 taxonomical groups. The potential of these isolates to reduce conidia production of B. graminis f. sp. tritici. in wheat was assessed in bioassays on potted winter wheat plants under controlled conditions. A set of ten superior isolates was subsequently tested in a series of trials on potted spring wheat plants under open field conditions. Isolates Tilletiopsis pallescens BC0441 and T. pallescens BC0850 significantly reduced the number of powdery mildew pustules per flag leaf by 30 to 62%. Slopes of the regression lines fitted to data on number of powdery mildew pustules during time were significantly reduced by the antagonists indicating that the powdery mildew epidemics were slowed down. Treatments with T. pallescens BC0441 and T. pallescens BC0850 also reduced leaf coverage with powdery mildew pustules in a small-scale field trial in spring wheat.

Regulation and safety considerations of somatic cell nuclear transfer-cloned farm animals and their offspring used for food production
Berg, Jan Pieter van der; Kleter, Gijs A. ; Kok, Esther J. - \ 2019
Theriogenology 135 (2019). - ISSN 0093-691X - p. 85 - 93.
Animal cloning - Animal husbandry - Food safety - Regulation - Risk assessment - Somatic cell nuclear transfer - Traceability

This document discusses recent developments in cloning of husbandry animals through somatic cell nuclear transfer, particularly with a view on improvements in their efficacy. Commercial developments in North and South America, Australia-New Zealand, and China are noted. The regulations and safety aspects surrounding the use of clones and their offspring for the purpose of food production are discussed. It is generally considered that foods from offspring of clones are no different than similar foods from conventional animals, yet besides safety, also ethical and animal welfare considerations come into play at the policy level. The related topic of detection and traceability of clones is discussed, which covers both molecular and documentary methods.

Equivalence limit scaled differences for untargeted safety assessments : Comparative analyses to guard against unintended effects on the environment or human health of genetically modified maize
Voet, Hilko van der; Goedhart, Paul W. ; García-Ruiz, Esteban ; Escorial, Concepción ; Tulinská, Jana - \ 2019
Food and Chemical Toxicology 125 (2019). - ISSN 0278-6915 - p. 540 - 548.
Arthropods - Equivalence test - Rat feeding study - Risk assessment - Standardised effect size - Unintended effects

Safety assessments guard against unintended effects for human health and the environment. When new products are compared with accepted reference products by broad arrays of measurements, statistical analyses are usually summarised by significance tests or confidence intervals per endpoint. The traditional approach is to test for statistical significance of differences. However, absence or presence of significant differences is not a statement about safety. Equivalence limits are essential for safety assessment. We propose graphs to present the results of equivalence tests over the array of endpoints. It is argued that plots of the equivalence limit scaled difference (ELSD) are preferable over plots of the standardised effect size (SES) used previously for similar assessments. The ELSD method can be used either with externally specified equivalence limits or with equivalence limits estimated from (historical) data. The method is illustrated with two examples: first, environmental safety of MON810 Bt maize was assessed using field trial count data of arthropods; second, human safety of herbicide tolerant NK603 maize was assessed using haematological, biochemical and organ weight data from a 90-day rat feeding study. All assessed endpoints were classified in EFSA equivalence categories I or II, implying full equivalence or equivalence more likely than not.

Opinion paper about organic trace pollutants in wastewater : Toxicity assessment in a European perspective
Pedrazzani, Roberta ; Bertanza, Giorgio ; Brnardić, Ivan ; Cetecioglu, Zeynep ; Dries, Jan ; Dvarionienė, Jolanta ; García-Fernández, Antonio J. ; Langenhoff, Alette ; Libralato, Giovanni ; Lofrano, Giusy ; Škrbić, Biljana ; Martínez-López, Emma ; Meriç, Süreyya ; Pavlović, Dragana Mutavdžić ; Papa, Matteo ; Schröder, Peter ; Tsagarakis, Konstantinos P. ; Vogelsang, Christian - \ 2019
Science of the Total Environment 651 (2019). - ISSN 0048-9697 - p. 3202 - 3221.
Aquatic ecosystem - Bioassays - Ecotoxicity - Micro-pollutants - Risk assessment - Wastewater treatment

This opinion paper focuses on the role of eco-toxicological tools in the assessment of possible impacts of emerging contaminants on the aquatic ecosystem, hence, on human health. Indeed, organic trace pollutants present in raw and treated wastewater are the pivot targets: a multidisciplinary approach allows defining the basic principles for managing this issue, from setting a proper monitoring campaign up to evaluating the optimal process treatment. Giving hints on trace pollutants fate and behaviour, attention is focused on the choice of the bioassay(s), by analysing the meaning of possible biological answers. Data interpretation and exploitation are detailed with the final goal of providing criteria in order to be able to select the best targeted treatment options. The manuscript deals with conventional and innovative analytical approaches for assessing toxicity, by reviewing laboratory and field assays; illustrative real scale and laboratory applications integrate and exemplify the proposed approach.

Pesticide residues in European agricultural soils – A hidden reality unfolded
Silva, Vera ; Mol, Hans G.J. ; Zomer, Paul ; Tienstra, Marc ; Ritsema, Coen J. ; Geissen, Violette - \ 2019
Science of the Total Environment 653 (2019). - ISSN 0048-9697 - p. 1532 - 1545.
Agricultural soils - European Union - Mixtures of pesticide residues - Predicted environmental concentrations in soil (PECs) - Risk assessment

Pesticide use is a major foundation of the agricultural intensification observed over the last few decades. As a result, soil contamination by pesticide residues has become an issue of increasing concern due to some pesticides' high soil persistence and toxicity to non-target species. In this study, the distribution of 76 pesticide residues was evaluated in 317 agricultural topsoil samples from across the European Union. The soils were collected in 2015 and originated from 11 EU Member States and 6 main cropping systems. Over 80% of the tested soils contained pesticide residues (25% of samples had 1 residue, 58% of samples had mixtures of two or more residues), in a total of 166 different pesticide combinations. Glyphosate and its metabolite AMPA, DDTs (DDT and its metabolites) and the broad-spectrum fungicides boscalid, epoxiconazole and tebuconazole were the compounds most frequently found in soil samples and the compounds found at the highest concentrations. These compounds occasionally exceeded their predicted environmental concentrations in soil but were below the respective toxic endpoints for standard in-soil organisms. Maximum individual pesticide content assessed in a soil sample was 2.05 mg kg−1 while maximum total pesticide content was 2.87 mg kg−1. This study reveals that the presence of mixtures of pesticide residues in soils are the rule rather than the exception, indicating that environmental risk assessment procedures should be adapted accordingly to minimize related risks to soil life and beyond. This information can be used to implement monitoring programs for pesticide residues in soil and to trigger toxicity assessments of mixtures of pesticide residues on a wider range of soil species in order to perform more comprehensive and accurate risk assessments.

Omics analyses of potato plant materials using an improved one-class classification tool to identify aberrant compositional profiles in risk assessment procedures
Kok, Esther ; Dijk, Jeroen van; Voorhuijzen, Marleen ; Staats, Martijn ; Slot, Martijn ; Lommen, Arjen ; Venema, Dini ; Pla, Maria ; Corujo, Maria ; Barros, Eugenia ; Hutten, Ronald ; Jansen, Jeroen ; Voet, Hilko van der - \ 2019
Food Chemistry 292 (2019). - ISSN 0308-8146 - p. 350 - 358.
Compositional analysis - Genetically modified organism - GMO - Omics profiling - Risk assessment

The objective of this study was to quantitatively assess potato omics profiles of new varieties for meaningful differences from analogous profiles of commercial varieties through the SIMCA one-class classification model. Analytical profiles of nine commercial potato varieties, eleven experimental potato varieties, one GM potato variety that had acquired Phytophtora resistance based on a single insert with potato-derived DNA sequences, and its non-GM commercial counterpart were generated. The ten conventional varieties were used to construct the one-class model. Omics profiles from experimental non-GM and GM varieties were assessed using the one-class SIMCA models. No potential unintended effects were identified in the case of the GM variety. The model showed that varieties that were genetically more distant from the commercial varieties were recognized as aberrant, highlighting its potential in determining whether additional evaluation is required for the risk assessment of materials produced from any breeding technique, including genetic modification.

Use of omics analytical methods in the study of genetically modified maize varieties tested in 90 days feeding trials
Corujo, Maria ; Pla, Maria ; Dijk, Jeroen van; Voorhuijzen, Marleen ; Staats, Martijn ; Slot, Martijn ; Lommen, Arjen ; Barros, Eugenia ; Nadal, Anna ; Puigdomènech, Pere ; Paz, José Luís La ; Voet, Hilko van der; Kok, Esther - \ 2019
Food Chemistry 292 (2019). - ISSN 0308-8146 - p. 359 - 371.
GMO (genetically modified organism) - Metabolomics - One-class model - Proteomics - Risk assessment - Transcriptomics

Genetically modified (GM) maize and their non-modified counterparts were compared using MON810 varieties, the only GMO event cultivated in Europe. The differences in grain samples were analysed by omics profiles, including transcriptomics, proteomics and metabolomics. Other cultivated maize varieties were analysed as a reference for the variability that will exist between cultivated varieties. The observed differences between modified and non-modified maize varieties do not exceed typical differences between non-modified varieties. The use of these advanced analytical approaches to analyse novel plant materials as compared to the results from animal feeding trials with whole foods is assessed. No indications were observed for changes in the GM varieties that warrant further investigations. Furthermore, it was shown that such indications will be obtained if maize samples of inferior quality are analysed similarly. Omics data provide detailed analytical information of the plant material, which facilitates a risk assessment procedure of new (GM) plant varieties.

Development of wheat with hypoimmunogenic gluten obstructed by the gene editing policy in europe
Jouanin, Aurélie ; Boyd, Lesley ; Visser, Richard G.F. ; Smulders, Marinus J.M. - \ 2018
Frontiers in Plant Science 871 (2018). - ISSN 1664-462X
Coeliac disease - Genetic modification - GM regulation - Innovation principle - Mutation breeding - New plant breeding technique - Public acceptance - Risk assessment

Coeliac Disease (CD) is an auto-immune reaction to gluten in 1–2% of the human population. A gluten-free (GF) diet, excluding wheat, barley, and rye, is the only remedy. This diet is difficult to adhere to, partly because wheat gluten is added to many processed products for their viscoelastic properties. In addition, GF products are less healthy and expensive. Wheat products containing only hypoimmunogenic gluten proteins would be a desirable option. Various gluten peptides that trigger CD have been characterized. A single wheat variety contains around hundred gluten genes, producing proteins with varying numbers of epitopes. Gene editing using CRISPR/Cas9 can precisely remove or modify the DNA sequences coding for immunogenic peptides. Wheat with hypoimmunogenic gluten thus exemplifies the potential of gene editing for improving crops for human consumption where conventional breeding cannot succeed. We describe here, in relation to breeding hypoimmunogenic wheat varieties, the inconsistencies of applying GM regulation in Europe for gene-edited plants while mutation breeding-derived plants are exempted. We explain that healthy products derived from this new technology may become available in the United States, Canada, Argentina and other countries but not in Europe, because of strict regulation of unintended GM risk at the expense of reduction the existing immunogenicity risks of patients. We argue that regulation of gene-edited plants should be based on scientific evidence. Therefore, we strongly recommend implementing the innovation principle. Responsible Research and Innovation, involving stakeholders including CD patient societies in the development of gene-editing products, will enable progress toward healthy products and encourage public acceptance.

Risk assessment paradigm for glutamate
Roberts, Ashley ; Lynch, Barry ; Rietjens, Ivonne M.C.M. - \ 2018
Annals of Nutrition & Metabolism 73 (2018)Suppl 5. - ISSN 0250-6807 - p. 53 - 64.
Acceptable daily intake - Glutamate - Macronutrient - Risk assessment

Background: Re-evaluation of the use of glutamic acid and glutamate salts (referred to as glutamate hereafter) by the European Food Safety Authority (EFSA) proposed a group acceptable daily intake (ADI) of 30 mg/kg body weight (bw)/day. Summary: This ADI is below the normal dietary intake, while even intake of free glutamate by breast-fed babies can be above this ADI. In addition, the pre-natal developmental toxicity study selected by EFSA, has never been used by regulatory authorities worldwide for the safety assessment of glutamate despite it being available for nearly 40 years. Also, the EFSA ignored that toxicokinetic data provide support for eliminating the use of an uncertainty factor for interspecies differences in kinetics. Key Messages: A 3-generation reproductive toxicity study in mice that includes extensive brain histopathology, provides a better point of departure showing no effects up to the highest dose tested of 6,000 mg/kg bw/day. Furthermore, kinetic data support use of a compound-specific uncertainty factor of 25 instead of 100. Thus, an ADI of at least 240 mg/kg bw/day would be indicated. In fact, there is no compelling evidence to indicate that the previous ADI of "not specified" warrants any change.

Introduction and summary of the 2018 dietary glutamate workshop
Cynober, Luc ; Fernstrom, John D. ; Koletzko, Berthold ; Rietjens, Ivonne M.C.M. ; Roberts, Ashley ; Tennant, David R. ; Tomé, Daniel ; Vorhees, Charles V. - \ 2018
Annals of Nutrition & Metabolism 73 (2018)Suppl 5. - ISSN 0250-6807 - 4 p.
Amino acid - European food safety authority - Glutamate - Risk assessment - Toxicology

The 2018 Dietary Glutamate Workshop was organized and sponsored by the International Glutamate Technical Committee to provide a platform for a broad expert discussion on all relevant aspects of glutamate metabolism and safety in human nutrition. The participants reached a consensus with previous safety evaluations conducted by the global expert bodies, but contradicted the 2017 re-evaluation of dietary glutamates by the European Food Safety Authority, which proposed a group acceptable daily intake (ADI) of 30 mg/kg body weight per day. The participants of the Workshop concluded that the present knowledge on metabolism, kinetics, developmental and general toxicity of dietary glutamates did not warrant a change in the previous ADI of "not specified."

Changes in work practices for safe use of formaldehyde in a university-based anatomy teaching and research facility
Scheepers, Paul T.J. ; Graumans, Martien H.F. ; Beckmann, Gwendolyn ; Dael, Maurice van; Anzion, Rob B.M. ; Melissen, Maarten ; Pinckaers, Nicole ; Wel, Luuk van; Werdt, Laurie M.A. de; Gelsing, Vera ; Linge, Albert van - \ 2018
International Journal of Environmental Research and Public Health 15 (2018)9. - ISSN 1661-7827
Carcinogenicity - Exposure assessment - Occupational hygiene - Risk assessment - Risk management

Anatomy teaching and research relies on the use of formaldehyde (FA) as a preservation agent for human and animal tissues. Due to the recent classification of FA as a carcinogen, university hospitals are facing a challenge to (further) reduce exposure to FA. The aim of this study was to reduce exposure to FA in the anatomy teaching and research facility. Workers participated in the development of improved work practices, both technical and organizational solutions. Over a period of 6 years mitigating measures were introduced, including improvement of a down-flow ventilation system, introduction of local exhaust ventilation, collection of drain liquid from displayed specimens in closed containers and leak prevention. Furthermore, some organizational changes were made to reduce the number of FA peak exposures. Stationary and personal air sampling was performed in three different campaigns to assess the effect of these new work practices on inhalation exposure to FA. Samples were collected over 8 h (full shift) and 15 min (task-based) to support mitigation of exposure and improvement of work practices. Air was collected on an adsorbent coated with 2,4-dinitrophenylhydrazine (DNPH) and analyzed by HPLC-UV. Geometric mean (GM) concentrations of FA in the breathing zone over a work-shift were 123 µg/m3 in 2012 and 114 µg/m3 in 2014, exceeding the workplace standard of 150 µg/m3 (8 h time-weighted average, TWA) on 46% of the workdays in 2012 and 38% of the workdays in 2014. This exposure was reduced to an average of 28.8 µg/m3 in 2017 with an estimated probability of exceeding the OEL of 0.6%. Task-based measurements resulted in a mean peak exposures of 291 µg/m3 in 2012 (n = 19) and a mean of 272 µg/m3 in 2014 (n = 21), occasionally exceeding the standard of 500 µg/m3 (15 min TWA), and were reduced to a mean of 88.7 µg/m3 in 2017 (n = 12) with an estimated probability of exceeding the OEL of 1.6%.

Natural occurrence of genotoxic and carcinogenic alkenylbenzenes in Indonesian jamu and evaluation of consumer risks
Suparmi, Suparmi ; Widiastuti, Diana ; Wesseling, Sebastiaan ; Rietjens, Ivonne M.C.M. - \ 2018
Food and Chemical Toxicology 118 (2018). - ISSN 0278-6915 - p. 53 - 67.
Alkenylbenzenes - Jamu - Margin of exposure (MOE) - Risk assessment
The consumer risks of jamu, Indonesian traditional herbal medicines, was assessed focussing on the presence of alkenylbenzene containing botanical ingredients. Twenty-three out of 25 samples contained alkenylbenzenes at levels ranging from 3.8 to 440 μg/kg, with methyleugenol being the most frequently encountered alkenylbenzene. The estimated daily intake (EDI) resulting from jamu consumption was estimated to amount to 0.2–171 μg/kg bw/day for individual alkenylbenzenes, to 0.9–203 μg/kg bw/day when adding up all alkenylbenzenes detected, and to 0.9–551 μg/kg bw/day when expressed in methyleugenol equivalents using interim relative potency (REP) factors. The margin of exposure (MOE) values obtained were generally <10,000 indicating a priority for risk management when assuming daily consumption during a lifetime. Using Haber's rule it was estimated that two weeks consumption of these jamu only once would not raise a concern (MOE >10,000). However, when considering use for two weeks every year during a lifetime, 5 samples still raise a concern. It is concluded that the consumption of alkenylbenzene containing jamu can be of concern especially when consumed on a daily basis for longer periods of time on a regular basis.
Evaluation of a single extraction test to estimate the human oral bioaccessibility of potentially toxic elements in soils : Towards more robust risk assessment
Rodrigues, S.M. ; Cruz, N. ; Carvalho, L. ; Duarte, A.C. ; Pereira, E. ; Boim, A.G.F. ; Alleoni, L.R.F. ; Römkens, P.F.A.M. - \ 2018
Science of the Total Environment 635 (2018). - ISSN 0048-9697 - p. 188 - 202.
ISO-17586:2016 - Oral bioaccessibility - Potentially toxic elements - Risk assessment - SBET - UBM
Intake of soil by children and adults is a major exposure pathway to contaminants including potentially toxic elements (PTEs). However, only the fraction of PTEs released in stomach and intestine are considered as bioaccessible and results from routine analyses of the total PTE content in soils, therefore, are not necessarily related to the degree of bioaccessibility. Experimental methods to determine bioaccessibility usually are time-consuming and relatively complicated in terms of analytical procedures which limits application in first tier assessments. In this study we evaluated the potential suitability of a recently developed single extract method (ISO-17586:2016) using dilute (0.43 M) nitric acid (HNO3) to mimic the bioaccessible fraction of PTEs in soils. Results from 204 soils from Portugal, Brazil and the Netherlands including all major soil types and a wide range of PTEs' concentrations showed that the extraction efficiency using 0.43 M HNO3 of Ba, Cd, Cu, Ni, Pb and Zn in soils is related to that of in vitro methods including the Simple Bioaccessibility Extraction Test (SBET) and Unified BARGE Method (UBM). Also, differences in the degree of bioaccessibility resulting from differences in parent material, geology and climate conditions did not affect the response of the 0.43 M HNO3 extraction which is a prerequisite to be able to compare results from different soils. The use of 0.43 M HNO3 as a first screening of bioaccessibility therefore offers a robust and representative way to be included in first tier standard soil tests to estimate the oral bioaccessibility. Capsule: The single dilute (0.43 M) nitric acid extraction can be used in first tier soil risk assessment to assess both geochemical reactivity and oral bioaccessibility of PTEs.
Avoidance tests as a tool to detect sublethal effects of oil-impacted sediments
Szczybelski, Ariadna S. ; Kampen, Tineke ; Vromans, Joris ; Peeters, Edwin T.H.M. ; Heuvel-Greve, Martine J. van den; Brink, Nico W. van den; Koelmans, Albert A. - \ 2018
Environmental Toxicology and Chemistry 37 (2018)6. - ISSN 0730-7268 - p. 1757 - 1766.
Amphipod - Avoidance - Benthic macroinvertebrates - Distillate marine grade A oil - Oil spills - Risk assessment
Currently, risk assessment for oil contamination does not consider behavioral responses of benthos to oil toxicity. Avoidance of oil-contaminated sediment by benthic amphipods, however, may be a highly sensitive endpoint for sublethal effects of commonly used distillate fuels. In the present study, the avoidance behavior of temperate freshwater (Gammarus pulex) and marine (Gammarus locusta) amphipods was tested by allowing them to choose between a reference sediment and a distillate marine grade A (DMA) oil-spiked sediment. Avoidance of DMA-spiked sediment at 1000mg/kg dry weight was significant within the total exposure time (96h) in G. pulex and within the first 72h in G. locusta in 1 of 2 tests. Absence of DMA avoidance at lower concentrations (≤250mg/kg dry wt) indicates that test species can only detect DMA above these concentrations. However, sensitivity to oil may vary according to the phenology and physiological conditions of the populations involved, such as the species temperature tolerance and reproductive stage. The results suggest that avoidance tests may be used as an alternative to traditional chronic toxicity tests provided that a causal link between avoidance and long-term effects can be established.
Detection of titanium particles in human liver and spleen and possible health implications
Heringa, M.B. ; Peters, R.J.B. ; Bleys, R.L.A.W. ; Lee, M.K. van der; Tromp, P.C. ; Kesteren, P.C.E. van; Eijkeren, J.C.H. van; Undas, A.K. ; Oomen, A.G. ; Bouwmeester, H. - \ 2018
Particle and Fibre Toxicology 15 (2018)1. - ISSN 1743-8977
Human liver - Human spleen - Nanoparticle - Quantification - Risk assessment - Sp-ICP-HRMS - Tissue level - Titanium dioxide
Background: Titanium dioxide (TiO2) is produced at high volumes and applied in many consumer and food products. Recent toxicokinetic modelling indicated the potential of TiO2 to accumulate in human liver and spleen upon daily oral exposure, which is not routinely investigated in chronic animal studies. A health risk from nanosized TiO2 particle consumption could not be excluded then. Results: Here we show the first quantification of both total titanium (Ti) and TiO2 particles in 15 post-mortem human livers and spleens. These low-level analyses were enabled by the use of fully validated (single particle) inductively coupled plasma high resolution mass spectrometry ((sp)ICP-HRMS) detection methods for total Ti and TiO2 particles. The presence of TiO2 in the particles in tissues was confirmed by Scanning Electron Microscopy with energy dispersive X-ray spectrometry. Conclusions: These results prove that TiO2 particles are present in human liver and spleen, with ≥24% of nanosize (< 100 nm). The levels are below the doses regarded as safe in animals, but half are above the dose that is deemed safe for liver damage in humans when taking into account several commonly applied uncertainty factors. With these new and unique human data, we remain with the conclusion that health risks due to oral exposure to TiO2 cannot be excluded.
Site-specific aftercare completion criteria for sustainable landfilling in the Netherlands : Geochemical modelling and sensitivity analysis
Dijkstra, Joris J. ; Zomeren, André van; Brand, Ellen ; Comans, Rob N.J. - \ 2018
Waste Management 75 (2018). - ISSN 0956-053X - p. 407 - 414.
Aftercare completion - Environmental protection criteria - Geochemical modelling - Risk assessment - Sensitivity analysis - Sustainable landfill management
A novel, regulatory accepted approach is developed that enables competent authorities to decide whether landfill aftercare can be reduced or terminated. Our previous paper (Brand et al., Waste Management 2016, 56, 255–261, outlines the general approach, that consists of a 10-year treatment phase (e.g., aeration, leachate recirculation), in combination with site-specific Environmental Protection Criteria (EPC) for contaminant concentrations in the landfill leachate after treatment. The current paper presents the unique modelling approach by which the site-specific EPC are derived. The modelling approach is based on the use of mechanistic multi-surface geochemical models covering the main sorption processes in soils underneath the landfills, and is composed of widely-accepted surface complexation models in combination with published “generic” parameter sets. This approach enables the consideration of the main site-specific soil properties that influence the attenuation of emitted contaminants. In addition, the sensitivity of the EPC is shown for variation of the main physicochemical-assumptions and policy-based decisions. Site-specific soil properties have been found to substantially determine the EPC and include soil-pH, dissolved organic matter, and iron-(hydr)oxide content. Apart from the sorption capacity of the local soil, EPC also depend strongly on the assumed dilution with local groundwater in the saturated zone. An important policy-related decision that influences the calculated EPC is the assessment period during which the groundwater is protected. The transparent setup of the approach using geochemical modelling, the explicit consideration of site-specific properties and the achieved regulatory acceptance may also stimulate application to landfills in other countries.
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