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The assessment of exposure of chemicals to environment and to human via the environment is of major concern for policy and industry and ultimately benefits all citizens. Currently many different types of exposure models are available. However, not all exposure models are designed for the same goal. Exposure assessment of chemicals depends highly on the context. In order to allow a comparison between and selection of exposure models, a transparent and objective framework based on a comprehensive list of scoring factors was developed. A comprehensive list of criteria was set up to structure the characteristics of the exposure tools. These criteria were divided into two categories: general and framework/context specific criteria. The general criteria were transferred into questions and were scored on importance by an expert panel. The framework specific criteria, which are highly context specific, received a score based on their applicability and importance in a certain type of framework. The following regulatory and sustainability driven frameworks were considered: REACH regulation, Plant Protection Products Regulation, Biocidal Product Regulation, environmental/spatial oriented directives (e.g. Water Framework Directive), Food oriented directives (e.g. Food Supplement Directive), product or process certification, site specific impact assessment and sustainability assessment. After scoring the criteria, a list of exposure models (such as EUSES, CalTOX, QUASI, 4FUN, USETOX, GREATER, PEARL, etc.) were evaluated using the Multi-Criteria Decision analysis (MCDA). The MCDA approach is a decision support tool, which allowed us to rank the different exposure models per framework. In conclusion, this methodology is ideally situated to determine the strengths and weaknesses of exposure models and to determine the suitability of a model towards a certain type of framework.

The assessment of risks to human health from chemicals is of major concern for policy and industry and ultimately benefits all citizens. In this process, exposure assessment is generally considered to be the weakest point, because currently available tools show major flaws such as lack of integrated approach for assessment of combined stressors (i.e. a number of potential pollutants), widespread use of 'worst-case' scenarios leading to over-conservative results and lack of uncertainty/sensitivity tools that allow identifying the important exposure drivers. To overcome these drawbacks, the FP6 project 2-FUN produced prototype software containing a library of models for exposure assessment, coupling environmental multimedia and pharmacokinetic models. The objective of the 4FUN project is to demonstrate, innovate and exploit this prototype software, to standardise it, to transfer it to stakeholders and guarantee its long term technical and economic viability. In order to optimize the prototype, the 2-Fun tool and other exposure tools were evaluated. First, a list of existing exposure tools, mainly multimedia models similar to 2-FUN, was composed based on literature review. The models were selected to cover a comprehensive range of exposure situations, in terms of the sources of exposure, the exposure pathways, and the receptor populations. Next, all exposure models were reviewed using a set of transparent and structured criteria, which were organised according to four lines of evidence: reliability, relevance, uncertainty and practical use. Each line of evidence is subdivided into categories, which are further subdivided into specific sub-categories. Finally, subcategories are composed of assessment criteria, which are evaluated through the use of questions. This approach makes it possible to put the 2-FUN tool in perspective and to identify the list of actions necessary for updating the design of the 2-FUN tool.

Monitoring the plasma membrane potential and its changes can be a time consuming and challenging task especially when conventional electrophysiological techniques are used. The use of potentiometricfluorophores, namely tetramethylrhodamine methylester (TMRM), and digital imaging devices (laser scanning confocal microscopy) provides reliable and time efficient method. Two scorpion pore-forming peptides, namely PP and OP1, were used as a tool to induce depolarization of the plasma membrane potential of neuroblastoma cell line and cardiac myocytes. Alternative methods for the neuroblastoma cells and cardiac myocytes were used. Depolarization of the neuroblastoma cells was calibrated with 140 mM KCl solution with 1 ìM valinomycin, after which intensity readers were substituted in the Nernst equation for quantification. Calibration of the alternative method used of the cardiac myocytes’ plasma membrane potential changes was calibrated with the use of 5, 20, 40, and 80 mM KCl solutions with 1 ìM valinomycin. A calibration curve was then constructed from which plasma membrane potential could be calculated

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Food intake is one of the principal exposure routes of polybrominated diphenyl ethers (PBDEs) in humans. This study focuses on fish consumption as a PBDE exposure route. A probabilistic intake assessment of PBDEs and healthy long chain omega-3 PUFAs (LC n-3 PUFAs) was conducted for Belgian fish consumers in order to study the balance of the intake of LC n-3 PUFAs and PBDEs. Based on the observed fish consumption level in the sample, the mean intake of brominated diphenyl ether (BDE)-28, 47, 99, 100, 153, and 154 via fish was 0.85 ng/kg body weight (bw)/day and the intake of LC n-3 PUFAs was 3.45 mg/kg bw/day, being low compared to the recommendations. Scenario analyses showed that consuming 150 g salmon twice a week is advisable to achieve the recommended LC n-3 PUFA intake with a rather low PBDE intake. When replacing 150 g salmon by herring, the PBDE intake is higher without an increase in LC n-3 PUFAs. In contrast, the combination of cod and salmon leads to a similar PBDE intake compared to twice a week salmon, but to a lower LC n-3 PUFA intake. In conclusion, the methodology presented in the paper allows balancing benefits and risks related to fish consumption.

Seafood represents a natural source of valuable nutrients (e.g., long chain omega-3 poly-unsaturated fatty acids (LC n-3 PUFAs), vitamin D, and iodine), but the favourable health perception is troubled by the presence of contaminants (e.g., PCBs, dioxin-like compounds, and (methyl) mercury (MeHg)). This dualism forms the basis for an important public health conflict. The objective of this study was to calculate and evaluate the simultaneous intake of multiple beneficial and harmful compounds (LC n-3 PUFAs, vitamin D, iodine, (Me)Hg, PCBs, and dioxin-like compounds) via seafood consumption in Belgium. A methodology and a software module were developed for executing probabilistic assessments of the simultaneous intake of multiple compounds leading to better insight in the problematic nature of food items involving both health benefits and risks. The simulations concerning seafood consumption in Belgium predicted that, as far as only seafood consumption is concerned, the considered populations do not reach a sufficiently high intake for the three nutrients considered (LC n-3 PUFAs, vitamin D, and iodine). Regarding the contaminants, (Me)Hg contamination of seafood on the Belgian market does not seem to be an issue of major toxicological concern. In contrast, for dioxin-like compounds the tolerable daily intake is reached by people with high seafood consumption.

Objectives Dietary intake of long-chain (LC) n-3 PUFA in developed countries is low compared with recommendations. Fish is naturally rich in LC n-3 PUFA, but is also a dietary source of heavy metals and organic pollutants. We investigated whether the recommendation for LC n-3 PUFA could be reached through fish consumption, without exceeding the provisional tolerable weekly intake of methylmercury (MeHg) and the tolerable weekly intake (TWI) of dioxin-like compounds. Also, the contribution of margarines enriched with LC n-3 PUFA was assessed.Design Published nutrient and contaminant data were used in a probabilistic model to calculate the simultaneous nutrient and contaminant intake for different fish consumption scenarios.Results The Belgian recommendation for EPA + DHA (0·3 % of total energy intake) can be reached by consuming fatty fish a minimum of twice a week, or by varying between lean and fatty fish a minimum of three times a week. At this fish consumption level, MeHg intake is not an issue of toxicological concern. The intake of dioxin-like compounds approximates the TWI when consuming fatty fish more than twice a week, this being a potential toxicological risk because other food items also contribute to the weekly intake of dioxin-like compounds. Use of margarine enriched with LC n-3 PUFA can help to increase LC n-3 intake, on average by 159 mg/d.Conclusions Combination of regular fish consumption (twice a week) with important contribution of fatty fish species, in combination with regular consumption of margarine enriched with EPA + DHA, can be advised to achieve the recommendation for LC n-3 intake.

F4 fimbriae are the major colonization factors associated with porcine neonatal and postweaning diarrhea caused by enterotoxigenic Escherichia coli (ETEC). Via the chaperone/usher pathway, the F4 are assembled as long polymers of the major subunit FaeG, which also possesses the adhesive properties of the fimbriae. Being highly stable and mucosally immunogenic F4/FaeG offers a unique model system to study oral vaccination against ETEC-induced postweaning diarrhea (PWD). PWD is a major problem in piggeries worldwide and results in significant economic losses. No vaccine is currently available to protect piglets against PWD. Transgenic plants provide an economically feasible platform for large-scale production of vaccine antigens for animal health. Here, the capacity of transgenic plants to produce FaeG was evaluated. Using the model plant tobacco, FaeG was directed to different subcellular compartments by specific targeting signals. Targeting of FaeG into chloroplasts offered a superior accumulation level of 1% of total soluble proteins over the endoplasmic reticulum and the apoplast. Intrinsically, the incomplete fold of fimbrial subunits renders them unstable and susceptible to aggregation and/or proteolytical degradation in the absence of a specific periplasmic chaperone. The chloroplast-targeted FaeG was purified from tobacco and crystallized. The crystal structure shows that chloroplasts circumvent the absence of the fimbrial assembly machinery by assembling FaeG into strand-swapped dimers. Moreover, the FaeG-dimers retained the key properties of an oral vaccine, i.e. stability in gastrointestinal conditions, binding to porcine intestinal F4 receptors, and inhibition of the F4+ ETEC attachment to F4R. To investigate the oral immunogenicity, the FaeG protein was expressed in the crop plants alfalfa and barley. Desiccated alfalfa plants and barley grains stored FaeG in a stable form for years. When the transgenic alfalfa plants and cholera toxin were orally co-administered to weaned piglets, F4-specific systemic and mucosal immune responses were induced and the duration and number of F4+ E. coli excretion following F4+ ETEC challenge were reduced. In conclusion, these results suggest that transgenic plants producing the FaeG subunit protein could be used for production and delivery of oral vaccines against porcine PWD.

The aim of food consumption is to provide people with the daily necessary energy, macro- and micronutrients in order to meet recommendations and to be able to execute daily tasks. What people need are the beneficial compounds that can be found in food products. Nevertheless, people risk to ingest simultaneously compounds that can have toxicological effects. These harmful compounds can on the one hand occur naturally in food, but on the other hand anthropogenic or man-made processes can lead to contamination of food products1. As such, food items can contain benefits as well as risks for consumers. A food group for which this nutritional-toxicological conflict is well-known and largely discussed in the scientific world and in the media is fish and shellfish, also named seafood or marine food. On the one hand, fish and shellfish represent a unique source of long chain poly-unsaturated fatty acids of the omega-3 family, particularly EPA and DHA. Moreover, they also contain a number of other valuable nutrients, like high quality amino acids and micronutrients like vitamin D and iodine. Therefore, it is generally accepted that seafood is important in a healthy and balanced omnivorous human diet. But on the other hand, this favourable health perception of seafood is troubled by less favourable information regarding the potential adverse health impact of chemical contamination of marine foods. Persistent organochlorine compounds, like PCBs, dioxin-like substances, and organochlorine pesticides (DDT/DDE) as well as heavy metals, e.g. mercury, accumulate in the marine food chain. This overall picture forms the basis for a conflictuous model between dietary recommendations and toxicological safety assurance. Therefore, it is useful to carry out a risk-benefit analysis to quantify the nutritional-toxicological conflict linked with seafood consumption. One important step in this risk-benefit analysis is a detailed intake assessment of nutrients and contaminants of interest by fish consumption. The model used for this intake assessment as well as the created output is described in this abstract, with a focus on the methodology and not on the results as such.