Residue Levels of Pesticides on Fruits for Use in Wildlife Risk Assessments.

The guidance document on risk assessment for birds and mammals (GD) provides generic residue values of pesticides on potential diet items for use in wildlife risk assessments. For most diet items, these values are based on a large number of residue studies. However, the default residues per unit dose (RUD; standardized for application of 1 kg substance per hectare) values for fruits were taken from a few literature trials of unclear relevance for regulatory purposes. These trials were conducted according to neither current European Union (EU) agricultural practice nor to recommendations given in the GD about how to conduct wildlife-relevant residue studies. Therefore, field study data on fruit residue levels from applications of pesticides in fruiting crops were compiled and evaluated. Corresponding studies had been conducted during the last 26 y in the EU. In the final data set, 291 studies provided 1002 residue values in different fruits, including grapes, berries (currants, raspberries, gooseberries), fruits from orchards (apple, peach, pear, lemon, mandarin, orange, apricot, cherry, plum), gourds (pumpkins, cucumbers, squash, melons), and strawberries. This data set provides a basis for revising registration-relevant RUD values for fruits as potential diet items for birds and mammals in environmental wildlife risk assessments. The objective of this study was to estimate the resulting residue levels in different fruits determined under field conditions following the application of pesticides across their growing areas within the EU in diverse climatic areas that can be used directly in wildlife risk assessments. The large data set of usually about more than 100 residue values per "fruit group," all evaluated at EU member state level, revealed significantly lower RUDs compared to the current default RUDs presented in the GD. These new RUD values for fruits should be considered for use as default values in future bird and mammal risk assessments and in respective guidance documents. Integr Environ Assess Manag 2021;17:552-561. © 2020 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology Chemistry (SETAC).

Alkylation of adenosine deaminase and thioredoxin by acrylamide in human cell cultures.

Acrylamide is an alpha,beta-unsaturated vinyl monomer that causes cytotoxicity due to its alkylating properties. In recent years several proteins have been identified that are alkylated by acrylamide in vivo. This finding might explain the neurotoxic effects of acrylamide in humans. However, the list of potential acrylamide target proteins is far from being complete. In particular, the proteins that mediate the cytotoxicity of acrylamide in cell cultures remained unknown. Here we identify two novel acrylamide target proteins in human cell cultures (Jurkat, HepG2 and Caco-2), adenosine deaminase and thioredoxin.

Uptake of S-(3-amino-3-oxopropyl)-cysteine by Caco-2 cells.

Acrylamide is a reactive neurotoxin with a high intestinal bioavailability. Recently we have shown that under the pH regime of the gut acrylamide can react with proteins and that this reaction reduces the uptake of acrylamide in a gut model. On the other hand, using radioactive labeled acrylamide, Bjellaas et al. [Toxicol. Sci. 100, 374-380 (2007)] showed that in vivo the vast majority of orally administered acrylamide is absorbed and excreted as N-acetyl-S-(3-amino-3-oxopropyl)-cysteine with the urine. Therefore, we tested whether intestinal proteases can degrade a protein with acrylamide bound to cysteine residues. Furthermore we tested whether the product of this reaction, S-(3-amino-3-oxopropyl)-cysteine, can pass the intestinal barrier. Here we showed that S-(3-amino-3-oxopropyl)-cysteine is indeed a product of proteolytic degradation of acrylamide-treated proteins. Using Caco-2 cells as a gut model, we further showed that the non-protein amino acid S-(3-amino-3-oxopropyl)-cysteine is a substrate for the neutral and cationic amino acid transporter system. Hence we concluded that protein-bound acrylamide can be released in the intestine and that the resulting product S-(3-amino-3-oxopropyl)-cysteine is transported through the intestinal barrier and later excreted via the urine.

Reduction of acrylamide uptake by dietary proteins in a caco-2 gut model.

The report of elevated acrylamide levels in some foods raised an international health alarm, because acrylamide probably has carcinogenic, neurotoxic, and genotoxic properties. However, data on the bioavailability of acrylamide from food matrices in humans are limited. In particular, only little is known about the interactions of acrylamide with food ingredients. Using a human intestine model (Caco-2 cells), this study shows that acrylamide monomers are highly bioavailable and pass the cell monolayer via passive diffusion. Furthermore, acrylamide binds to dietary proteins such as chicken egg albumin under intestinal and cooking conditions. This binding reduces the concentration of acrylamide monomers and leads to a reduced uptake by Caco-2 cells. Hence, it is concluded that a protein-rich diet may reduce acrylamide uptake.

Focal bird species and risk assessment approach for nonagricultural grassland scenarios in Central Europe.

The European Food Safety Authority (EFSA) guideline on risk assessment identifies pesticide exposure scenarios for nontarget wildlife; however, this scheme is not applicable to nonagricultural grassland. For example, different habitats and human utilization on golf courses attract bird communities that differ from those found in agricultural fields with annual crop cycles. The present study determined focal bird species for amenity grasslands such as golf courses following the EFSA guideline. Based on published data and bird surveys, a total of 102 species were found on 13 golf courses in Central Europe. Approximately 58% of the species were recorded on >20% of the golf course and were classified as focal species candidates. Common kestrel (Falco tinnunculus), common linnet (Carduelis cannabina), wood pigeon (Columba palumbus), yellowhammer (Emberiza citrinella), white wagtail (Motacilla alba), and gray heron (Ardea cinerea) are the most adequate candidate focal species for exposure scenarios of carnivorous, granivorous, herbivorous, omnivorous, insectivorous, and piscivorous birds, respectively. Candidate species were verified on 3 golf courses in southwestern Germany in spring 2012. Observations on feeding behavior identified the main foraging areas of focal species. The results of the field work combined with data from the literature identified reliable exposure scenarios to assess the risk of pesticides to birds found on golf courses.