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The food enzyme glucan 1,4‐α‐maltotetraohydrolase (4‐α‐d‐glucan maltotetraohydrolase, EC 3.2.1.60) is produced with a genetically modified Bacillus licheniformis strain DP‐Dzr46 by Danisco US Inc. The genetic modifications do not give rise to safety concerns. The food enzyme is free from viable cells of the production organism and recombinant DNA. The glucan 1,4‐α‐maltotetraohydrolase food enzyme is intended to be used in baking processes. Based on the maximum use levels, dietary exposure to the food enzyme–Total Organic Solids (TOS) was estimated to be up to 0.405 mg TOS/kg body weight (bw) per day in European populations. The toxicity studies were carried out with another glucan 1,4‐α‐maltotetraohydrolase from B. licheniformis (strain DP‐Dzf24). The Panel considered this food enzyme as a suitable substitute to be used in the toxicological studies, because it derives from the same recipient strain as strain DP‐Dzr46, the location of the inserts is comparable, no partial inserts were present and the production methods are comparable. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90‐day oral toxicity study in rats. The Panel identified a no observed adverse effect level (NOAEL) at the highest dose of 94 mg TOS/kg bw per day that, compared with the estimated dietary exposure, results in a sufficiently high margin of exposure of at least 232. Similarity of the amino acid sequence to those of known allergens was searched and none was found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions by dietary exposure cannot be excluded, but the likelihood is considered to be low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

The food enzyme phospholipase C (EC 3.1.4.3) is produced with a genetically modified Komagataella phaffii (formerly Pichia pastoris) (strain PRF) by DSM. The genetic modifications do not give rise to safety concerns. The food enzyme is free from viable cells of the production organism and recombinant DNA. This phospholipase C is intended to be used in fats and oils processing for degumming. The residual amounts of total organic solids (TOS) are removed during refinement steps applied during fats and oils processing. Consequently, no dietary exposure was calculated. Genotoxicity tests did not indicate a safety concern. The systemic toxicity was assessed by means of a repeated dose 90‐day oral toxicity study in rats. The Panel identified a no observed adverse effect level (NOAEL) of at least 1,672 mg TOS/kg body weight per day, the highest dose tested. Similarity of the amino acid sequence to those of known allergens was searched and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions by dietary exposure cannot be excluded, but the likelihood is considered to be low. Based on the data provided and the removal of TOS during the fats and oils processing for degumming, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

The food enzyme has three declared activities (endo‐1,3(4)‐β‐glucanase EC 3.2.1.6, endo‐1,4‐β‐xylanase EC 3.2.1.8 and cellulase (endo‐1,4‐β‐d‐glucanase EC 3.2.1.4)) and is produced with a non‐genetically modified Mycothermus thermophiloides strain by Novozymes A/S. It is intended to be used in baking and brewing processes. For the two intended uses, based on the maximum use levels recommended and individual data from the EFSA Comprehensive European Food Database, dietary exposure to the food enzyme–Total Organic Solids (TOS) was estimated to be up to 0.411 mg TOS/kg body weight (bw) per day. Genotoxicity tests did not raise a safety concern. Systemic toxicity was assessed by a repeated dose 90‐day oral toxicity study in rats. From this study, the Panel identified a no observed adverse effect level (NOAEL) of at least 620 mg TOS/kg bw per day, the highest dose tested. When the NOAEL is compared to the estimated dietary exposure, this results in a margin of exposure of at least 1,500. A search was made for similarity of the amino acid sequence of the declared activities with those of known allergens. Four matches were found with endo‐1,3(4)‐β‐glucanase to known respiratory allergens, two from dust mites and two Aspergillus fumigatus allergens. The Panel considered that an allergic reaction upon oral ingestion of enzymes produced by M. thermophiloides strain NZYM‐ST in individuals respiratory sensitised to these allergens cannot be excluded, but the likelihood is considered to be low. Overall, the Panel concluded that, under the intended conditions of use and based on the data provided, this food enzyme does not give rise to safety concerns.

The food enzyme is a glucose isomerase (d‐xylose aldose‐ketose‐isomerase; EC 5.3.1.5) produced with a non‐genetically modified Streptomyces murinus strain NZYM‐GA by Novozymes A/S. The glucose isomerase is intended only to be used in an immobilised form in glucose isomerisation for the production of high fructose syrups. Residual amounts of total organic solids are removed by the purification steps applied during the production of high fructose syrups using the immobilised enzyme; consequently, dietary exposure was not calculated. Genotoxicity tests did not raise a safety concern. Similarity of the amino acid sequence to those of known allergens was searched and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions by dietary exposure cannot be excluded, but the likelihood to occur is considered to be low. Based on the data provided, the immobilisation process and the removal of total organic solids during the production of high fructose syrups, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

The food enzyme maltogenic amylase (glucan 1,4‐α‐maltohydrolase; EC 3.2.1.133) is produced with a genetically modified Bacillus subtilis strain NZYM‐SO by Novozymes A/S. The genetic modifications do not give rise to safety concerns. The food enzyme is free from viable cells of the production microorganism and recombinant DNA. This maltogenic amylase is intended to be used in baking processes. Based on the maximum use levels, dietary exposure to the food enzyme–total organic Solids (TOS) was estimated to be up to 0.556 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90‐day oral toxicity study in rats. The Panel identified a no observed adverse effect level at the mid‐dose of 318.4 mg TOS/kg bw per day that, compared with the estimated dietary exposure, results in a sufficiently high margin of exposure (at least 570). Similarity of the amino acid sequence to those of known allergens was searched and three matches were found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions upon dietary exposure to this food enzyme cannot be excluded, but the likelihood of such reactions to occur is considered to be low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Azo dyes represent the by far most important class of textile dyes. Their biotransformation by various skin bacteria may release aromatic amines (AAs) which might be dermally absorbed to a major extent. Certain AAs are well known to have genotoxic and/or carcinogenic properties. Correspondingly, azo dyes releasing one of the 22 known carcinogenic AAs are banned from clothing textiles in the European Union. In the present study, we investigated the mutagenicity of 397 non-regulated AAs potentially released from the 470 known textile azo dyes. We identified 36 mutagenic AAs via publicly available databases. After predicting their mutagenicity potential using the method by Bentzien, we accordingly allocated them into different priority groups. Ames tests on 18 AAs of high priority showed that 4 substances (22%) (CASRN 84-67-3, 615-47-4, 3282-99-3, 15791-87-4) are mutagenic in the strain TA98 and/or TA100 with and/or without rat S9 mix. Overall, combining the information from the Ames tests and the publicly available data, we identified 40 mutagenic AAs being potential cleavage products of approximately 180 different parent azo dyes comprising 38% of the azo dyes in our database. The outcome of this study indicates that mutagenic AAs in textile azo dyes are of much higher concern than previously expected, which entails implications on the product design and possibly on the regulation of azo dyes in the future.

Inorganic arsenic (iAs) is a contaminant present in food, especially in rice and rice-based products. Toxicity of arsenic compounds (As) depends on species and oxidative state. iAs species, such as arsenite (As(III)) and arsenate (As(V)), are more bioactive and toxic than organic arsenic species, like methylarsonic acid (MMA(V)) and dimethylarsinic acid (DMA(V)) or arsenosugars and arsenobetaine. An ion chromatography-inductively coupled-plasma-mass spectroscopy method was developed to separate the four following arsenic anions: As(III), As(V), MMA(V) and DMA(V). Sample preparation was done in mild acidic conditions to ensure species preservation. The predominant arsenic species found in rice and rice-based products, except for rice drinks, was As(III), with 60-80% of the total As content, followed by DMA(V) and As(V). MMA(V) was measured only at low levels (3%). Analyses of rice products (N = 105) intended for toddlers, including special products destined for infants and toddlers, such as dry form baby foods (N = 12) or ready-to-use form (N = 9), were done. It was found in this study that there is little or no margin of exposure. Risk assessment, using the occurrence data and indicated intake scenarios compared to reference BMDLs as established by EFSA, demonstrated toddlers with a high consumption of rice based cereals and rice drinks are at risk of high iAs exposure, for which a potential health risk cannot be excluded.

EFSA was asked by the European Commission to update the Scientific Opinion on methodological principles and scientific methods to be taken into account when establishing Reference Points for Action (RPAs) for non‐allowed pharmacologically active substances in food of animal origin. This guidance document presents a simple and pragmatic approach which takes into account both analytical and toxicological considerations. The RPA shall be based on the reasonably achievable lowest residue concentration that can unequivocally be determined by official control laboratories, i.e. the reasonably achievable lowest decision limit (CCα). The aim is to check whether this concentration is low enough to adequately protect the consumers of food commodities that contain that substance. The proposed step‐wise approach applies toxicological screening values (TSVs), based on genotoxic potential, pharmacological activity, as well as other effects of the substance. The highest dietary exposure corresponding to the reasonably achievable lowest CCα for the substance has to be estimated and compared with the TSV. Where equal to or lower than the TSV, the reasonably achievable lowest CCα can be accepted as the RPA. If higher, the sensitivity of the analytical method needs to be improved. In the case where no further analytical improvements are feasible within a short to medium time frame, a substance‐specific risk assessment should be considered. This also applies when the potential adverse effects do not allow use of the decision tree, as for high potency carcinogens, inorganic substances or compounds with allergenic effects or causing blood dyscrasias. The CONTAM Panel concluded that RPAs should be food matrix independent. RPAs cannot be applied to non‐edible matrices, which are also monitored for non‐allowed pharmacologically active substances.

International audience; Deoxynivalenol (DON) is a mycotoxin primarily produced by Fusarium fungi, occurring predominantly in cereal grains. Following the request of the European Commission, the CONTAM Panel assessed the risk to animal and human health related to DON, 3-acetyl-DON (3-Ac-DON), 15-acetyl-DON (15-Ac-DON) and DON-3-glucoside in food and feed. A total of 27,537, 13,892, 7,270 and 2,266 analytical data for DON, 3-Ac-DON, 15-Ac-DON and DON-3-glucoside, respectively, in food, feed and unprocessed grains collected from 2007 to 2014 were used. For human exposure, grains and grain-based products were main sources, whereas in farm and companion animals, cereal grains, cereal by-products and forage maize contributed most. DON is rapidly absorbed, distributed, and excreted. Since 3-Ac-DON and 15-Ac-DON are largely deacetylated and DON-3-glucoside cleaved in the intestines the same toxic effects as DON can be expected. The TDI of 1 lg/kg bw per day, that was established for DON based on reduced body weight gain in mice, was therefore used as a group-TDI for the sum of DON, 3-Ac-DON, 15-Ac-DON and DON-3-glucoside. In order to assess acute human health risk, epidemiological data from mycotoxicoses were assessed and a group-ARfD of 8 lg/kg bw per eating occasion was calculated. Estimates of acute dietary exposures were below this dose and did not raise a health concern in humans. The estimated mean chronic dietary exposure was above the group-TDI in infants, toddlers and other children, and at high exposure also in adolescents and adults, indicating a potential health concern. Based on estimated mean dietary concentrations in ruminants, poultry, rabbits, dogs and cats, most farmed fish species and horses, adverse effects are not expected. At the high dietary concentrations, there is a potential risk for chronic adverse effects in pigs and fish and for acute adverse effects in cats and farmed mink.

Cyclo-diBA, the cyclic product formed from bisphenol A and bisphenol A diglycidyl ether during production of epoxy resins, was measured in canned food using reversed phase HPLC with fluorescence detection. Half (9 of 17) of the samples of canned fish in oil collected in April 2010 contained cyclo-diBA with an average concentration of 1025 μg/kg and a maximum of 1980 μg/kg. In September 2012, cyclo-diBA was detectable (>25 μg/kg) in merely 13 from 44 such products; the average concentration in these was 807 μg/kg and the maximum now reached 2640 μg/kg. Fish in brine contained far less cyclo-diBA. The majority of the canned meat products contained cyclo-diBA at a mean concentration of 477 μg/kg and a maximum of 1050 μg/kg. All prepared meals, such as ravioli or soups, contained cyclo-diBA, with a mean at 287 μg/kg. In canned tomatoes, peas and other vegetables in water or fruits in syrup, no cyclo-diBA was detected (

Validated in vitro methods for skin corrosion and irritation were adopted by the OECD and by the European Union during the last decade. In the EU, Switzerland and countries adopting the EU legislation, these assays may allow the full replacement of animal testing for identifying and classifying compounds as skin corrosives, skin irritants, and non irritants. In order to develop harmonised recommendations on the use of in vitro data for regulatory assessment purposes within the European framework, a workshop was organized by the Swiss Federal Office of Public Health together with ECVAM and the BfR. It comprised stakeholders from various European countries involved in the process from in vitro testing to the regulatory assessment of in vitro data. Discussions addressed the following questions: (1) the information requirements considered useful for regulatory assessment; (2) the applicability of in vitro skin corrosion data to assign the corrosive subcategories as implemented by the EU Classification, Labelling and Packaging Regulation; (3) the applicability of testing strategies for determining skin corrosion and irritation hazards; and (4) the applicability of the adopted in vitro assays to test mixtures, preparations and dilutions. Overall, a number of agreements and recommendations were achieved in order to clarify and facilitate the assessment and use of in vitro data from regulatory accepted methods, and ultimately help regulators and scientists facing with the new in vitro approaches to evaluate skin irritation and corrosion hazards and risks without animal data. -® 2011 Elsevier Inc.

Tetrachlorinated butadienes (TetraCBDs), pentachlorinated butadienes (PentaCBDs) and hexachlorobutadiene (HexaCBD) were detected in groundwater wells of drinking water supplier near Basel up to maximally 157 ng/L (sum value), 15 ng/L (sum value), and

Providing sustainable and safe nutrition to the population is one of the main tasks of the modern food industry. While food packaging materials fulfill their invaluable protective role, certain substances can migrate from them into food. Switzerland is worldwide the only country, in which substances in printing inks for food packaging are regulated. Approx. 5000 substances are listed in Annex 10 of the Ordinance on Food Contact Materials FCM (SR 817.023. 21). Briefly, they were evaluated based on toxicity data and have a specific migration limit (part A). Alternatively, they should not be classified as CMR substances and not be detectable in food (< 10 ppb)(part B). In the order to identify potentially harmful compounds, we performed a virtual screening study along with a complex toxicokinetic characterization of chemical compounds contained in printing inks for FCM.

The interest in holistic considerations in the area of food safety is increasing. Risk managers may face the problem that reducing the risk of one compound may increase the risk of another compound. An example is the potential increase in mycotoxin levels due to a reduced use of fungicides in crop production. The Integrated Probabilistic Risk Assessment (IPRA) model was used to compare the estimated health impacts on humans caused by crops contaminated with the fungicides spiroxamine (SPI) and tebuconazole (TEB) or with the mycotoxins deoxynivalenol (DON) and zearalenone (ZEA). The IPRA model integrates a distribution characterising the exposure of individuals with a distribution characterising the susceptibility of individuals towards toxic effects. Its outcome, a distribution of Individual Margins of Exposure (IMoE), served as basis to perform comparisons of compounds, effects, countries, and population groups. Based on the available data and the assumptions made, none of the four compounds was found to have impact on human health in the addressed scenarios. The IMoE distributions were located as follows: DON < TEB = ZEA < SPI, showing DON to be the compound with the highest potential for negative health impacts. The presented approach can help risk managers to prioritise risk-reduction measures.

Urinary cadmium (Cd) excretion was measured within a representative Swiss collective. With a median of 0.23 µg/24 h (n = 1409) and the 95th percentile at 0.81 µg/24 h, no increased health risk for the general non-exposed population was identified. The independent variables Age, BMI and Smoking habit had a significant effect on urinary Cd excretion. No association was found with the region of residence and sex. A subsample comparison between 24-h and spot urines of the same subjects (n = 90) did not reveal an evident concentration difference for both creatinine-adjusted sample types. Dependencies on age and gender were observed for creatinine, which consequently impacts on the creatinine normalisation of urine samples.

Bisphenol F (BPF) was found in mustard up to a concentration of around 8 mg kg−1. Contamination of the raw products or caused by the packaging could be ruled out. Also, the fact that only the 4,4ʹ-isomer of BPF was detected spoke against contamination from epoxy resin or other sources where technical BPF is used. Only mild mustard made of the seeds of Sinapis alba contained BPF. In all probability BPF is a reaction product from the breakdown of the glucosinolate glucosinalbin with 4-hydroxybenzyl alcohol as an important intermediate. Hot mustard made only from brown mustard seeds (Brassica juncea) or black mustard seeds (Brassica nigra) contained no BPF. BPF is structurally very similar to bisphenol A and has a similar weak estrogenic activity. The consumption of a portion of 20 g of mustard can lead to an intake of 100–200 µg of BPF. According to a preliminary risk assessment, the risk of BPF in mustard for the health of consumers is considered to be low, but available toxicological data are insufficient for a conclusive evaluation. It is a new and surprising finding that BPF is a natural food ingredient and that this is the main uptake route. This insight sheds new light on the risk linked to the family of bisphenols., Graphical Abstract

Mineral paraffins widely occur in foods, but are also ingredients of body lotions, lip sticks, and breast salves. In this study it is shown that mineral paraffins are detectable in human milk. Thirty three human milk samples were found to contain mineral C 15 –C 45 paraffins at a mean concentration of 95 ± 215 mg/kg fat and a maximum of 1300 mg/kg. The mineral paraffins found in human milk had average molecular weights between C 23 and C 33 , and often more than half of the paraffins were below C 25 . Beside exposure of babies via human milk, the intake by direct licking off salves (in the worst case consisting of vaseline) from the breast of their nursing mothers may be much higher. In a worst case situation, daily intake from breast care products by babies is estimated to reach 40 mg/kg bw. Many compositions do not comply with the specifications and a temporary group ADI of 0–4 mg/kg bw established by the SCF. This possible exposure of babies either calls for a toxicological re-evaluation of the mineral paraffins or for measures ensuring that exposure of babies is reduced.

Azole compounds play a key role as antifungals in agriculture and in human mycoses and as non-steroidal antiestrogens in the treatment of estrogen-responsive breast tumors in postmenopausal women. This broad use of azoles is based on their inhibition of certain pathways of steroidogenesis by high-affinity binding to the enzymes sterol 14-alpha-demethylase and aromatase. Sterol 14-alpha-demethylase is crucial for the production of meiosis-activating sterols, which recently were shown to modulate germ cell development in both sexes of mammals. Aromatase is responsible for the physiologic balance of androgens and estrogens. At high doses, azole fungicides and other azole compounds affect reproductive organs, fertility, and development in several species. These effects may be explained by inhibition of sterol 14-alpha-demethylase and/or aromatase. In fact, several azole compounds were shown to inhibit these enzymes in vitro, and there is also strong evidence for inhibiting activity in vivo. Furthermore, the specificity of the enzyme inhibition of several of these compounds is poor, both with respect to fungal versus nonfungal sterol 14-alpha-demethylases and versus other P450 enzymes including aromatase. To our knowledge, this is the first review on sterol 14-alpha-demethylase and aromatase as common targets of azole compounds and the consequence for steroidogenesis. We conclude that many azole compounds developed as inhibitors of fungal sterol 14-alpha-demethylase are inhibitors also of mammalian sterol 14-alpha-demethylase and mammalian aromatase with unknown potencies. For human health risk assessment, data on comparative potencies of azole fungicides to fungal and human enzymes are needed.

Azo dyes in textiles may release aromatic amines after enzymatic cleavage by skin bacteria or after dermal absorption and metabolism in the human body. From the 896 azo dyes with known chemical structure in the available textile dyes database, 426 azo dyes (48%) can generate one or more of the 22 regulated aromatic amines in the European Union in Annex XVII of REACH. Another 470 azo dyes (52%) can be cleaved into exclusively non-regulated aromatic amines. In this study, a search for publicly available toxicity data on non-regulated aromatic amines was performed. For a considerable percentage of non-regulated aromatic amines, the toxicity database was found to be insufficient or non-existent. 62 non-regulated aromatic amines with available toxicity data were prioritized by expert judgment with objective criteria according to their potential for carcinogenicity, genotoxicity, and/or skin sensitization. To investigate the occurrence of azo dye cleavage products, 153 random samples of clothing textiles were taken from Swiss retail outlets and analyzed for 22 high priority non-regulated aromatic amines of toxicological concern. Eight of these 22 non-regulated aromatic amines of concern could be detected in 17% of the textile samples. In 9% of the samples, one or more of the aromatic amines of concern could be detected in concentrations >30 mg/kg, in 8% of the samples between 5 and 30 mg/kg. The highest measured concentration was 622 mg/kg textile. There is an obvious need to assess consumer health risks for these non-regulated aromatic amines and to fill this gap in the regulation of clothing textiles.

Inhibitory effects of several organotin compounds on cytochrome P4501A (CYP1A) induction response and enzyme activity have been analyzed in fish hepatoma cells (PLHC-1). In a first set of experiments, cells were exposed for 3 d to 3-methylcholanthrene (3-MC), an inducer of CYP1A. Simultaneously, series of dilutions of the widely used organotin compounds triphenyltin (TPT), tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) were added to the cells. Relative CYP1A protein contents were measured in an enzyme-linked immunosorbent assay (ELISA), CYP1A activities in the ethoxyresorufin-O-deethylase (EROD) assay, and cytotoxicity in the neutral red (NR) assay. Induction of CYP1A protein and activity was found in the presence of low concentrations of organotins and 3-MC. The three assays did not show significant differences in sensitivity for TBT and TPT. Concentrations that reduced control values by 50% (EC50) were between 1.6·10−7 M and 3.5·10−7 M, which emphasizes the high cytotoxicity of both compounds. In contrast, DBT led to inhibition of EROD activity at significantly lower concentrations (1.2·10−6 M) than loss of CYP1A protein in the ELISA (9.0·10−6 M) and cytotoxicity in the NR assay (8.7·10−6 M). In a second set of experiments, reduction of CYP1A activity was also obtained after sequential exposure to 3-MC and organotins. In a third set of experiments, lysates of CYP1A-induced cells were exposed to organotins. Organotins caused a 50% inhibition of EROD activity at significantly higher concentrations (namely at 4.7·10−5 M and 6.7·10−5 M for TBT and DBT, respectively, and at 1.1·10−3 M for MBT) than in the first set of experiments. For TBT, a noncompetitive inhibitory mechanism on CYP1A enzyme activity has been found. The experiments in this study demonstrate inhibitory capacities of TBT and TPT, but also of DBT and MBT, on the CYP1A system in fish cells. The results lead to the conclusion that the effect is mainly caused by direct inhibition of enzyme activity, not by inhibition of CYP1A protein synthesis. The induction of CYP1A protein and activity in the presence of both an inducer (3-MC) and a low concentration of inhibitors (organotins) indicates that organotins do not interfere with the Ah receptor binding, but act at the CYP1A protein level.

An enzyme-linked immunosorbent assay (ELISA) for measuring cytochrome P4501A (CY1A) expression in vitro in fish hepatoma cells is described. Cells were cultured as monolayers in 96–microwell cell culture plates and exposed to polychlorinated biphenyl (PCB) congeners 77, 105, 153, and 169; 3–methylcholanthrene (3–MC), and β-naphthoflavone (BNF) for 3 d. Relative CYP1A protein content, CYP1A enzymatic activity, and total protein content were determined directly within the wells. At low concentrations of PCB 77, PCB 169, and 3–MC, the ethoxyresorufin-O - deethylase (EROD) activity was induced, but it was inhibited at high concentrations of these compounds. However, CYP1A protein content measured in an ELISA performed with intact cells increased monotonically in response to the concentration. No CYP1A induction was observed for PCB 105 and PCB 153. Because comparison between EROD activity and CYP1A amount gives information about the catalytic efficiency of CYP1A in the cells, this noncompetitive, solid-phase ELISA is recommended as a complementary method to the EROD assay. This novel ELISA method may be an accurate in vitro technique for a rapid and sensitive screening of CYP1A-inducible compounds.

Cytotoxicity in vitro to fish hepatoma cells PLHC-1 has been analyzed for a series of 21 organotin compounds consisting of all degrees of alkylation and arylation. The sensitivity of the neutral red (NR) assay and the tetrazolium salt reduction (MTT) assay was similar for most of the organotin compounds. Cytotoxic effects were found at concentrations between 10 −8 M and 10 −2 M. For various trisubstituted organotin compounds, including tributyltin and triphenyltin, which are used in antifouling paints and as pesticides, respectively, cytotoxic concentrations in the range of 10 −8 M to 10 −6 M were observed. Based on the concentration reducing NR uptake by 50% (NR 50 ), the sequence of Cytotoxicity amongst butyltins was tributyltin ⪢ bis(tributyl)-tin ⪢ dibutyltin ⪢ tetrabutyltin ⪢ butyltin ⪢ tin(IV). Tributyltin induced effects on cell functions quickly, as a reduction in NR uptake by 30% was recorded after 30 min exposure to 4 · 10 −7 M. The ranking order in Cytotoxicity in the MTT assay of phenylated organotins was triphenyltin ⪢ diphenyltin ⪢ phenyltin ⪢ tin(IV). Cytotoxic concentrations of tributyltin and triphenyltin measured in the bromodeoxyuridine (BrdU) assay and with the crystal violet (CV) staining method do not differ significantly from those determined in the NR and MTT assay. Tri-and disubstituted organotin compounds exhibit a significant correlation between the noctanol/water partition coefficient (logK ow ) and the NR 50 ( n = 10, r = 0.86, P = 0.001) and the MTT 50 values ( n = 11, r = 0.85, P = 0.001), respectively. In addition, good qualitative correlations between in vitro Cytotoxicity data and in vivo fish toxicity data were found (for NR assay n = 8, r = 0.86, P = 0.001; for MTT assay n = 9, r = 0.80, P = 0.001). he results indicate that the in vitro Cytotoxicity assays using PLHC-1 cells are useful tools for the estimation of the acute toxicity to fish of organotins and possibly other compounds.

Tetrachlorinated butadienes (TetraCBDs), pentachlorinated butadienes (PentaCBDs) and hexachloro-1,3-butadiene (hexachlorobutadiene or HexaCBD) are environmental contaminants that can occur in groundwater and drinking water at specific sites. While some toxicological data exist for HexaCBD, only few or no toxicity data are available for TetraCBDs and PentaCBDs. In view of structural alerts for potential genotoxicity and carcinogenicity, the genotoxicity of these substances was examined in the Salmonella typhimurium mutagenicity assay (Ames test) and in the in vitro chromosome aberration test. All of the tested polychlorinated butadienes induced chromosome aberrations. Such an effect of HexaCBD is reported here for the first time. In addition, 1,1,3,4-TetraCBD and 1,2,3,4-TetraCBD were positive in the Ames test while the other polychlorinated butadienes including HexaCBD were negative. From these findings it is concluded that certain incompletely chlorinated butadienes have a different genotoxic profile than the completely halogenated HexaCBD, which is of relevance for the risk assessment of these compounds.

Risk managers need detailed information on (1) the type of effect, (2) the size (severity) of the expected effect(s) and (3) the fraction of the population at risk to decide on well-balanced risk reduction measures. A previously developed integrated probabilistic risk assessment (IPRA) model provides quantitative information on these three parameters. A semi-quantitative tool is presented that combines information on these parameters into easy-readable charts that will facilitate risk evaluations of exposure situations and decisions on risk reduction measures. This tool is based on a concept of health impact categorization that has been successfully in force for several years within several emergency planning programs. Four health impact categories are distinguished: No-Health Impact, Low-Health Impact, Moderate-Health Impact and Severe-Health Impact. Two different charts are presented to graphically present the information on the three parameters of interest. A bar plot provides an overview of all health effects involved, including information on the fraction of the exposed population in each of the four health impact categories. Secondly, a Health Impact Chart is presented to provide more detailed information on the estimated health impact in a given exposure situation. These graphs will facilitate the discussions on appropriate risk reduction measures to be taken.

The benchmark dose (BMD) approach is being increasingly used in the area of food risk assessment because it offers several advantages compared to the conventional no-observed-adverse-effect-level approach. The aim of this work was to check the applicability of the BMD approach on toxicity data available from pesticides, mycotoxins and natural toxins. Based on toxicological evaluations, the pivotal study was identified. Detailed data from the original study were retrieved and used for BMD modelling. Twenty-five studies used for BMD modelling were analysed with regard to study design: total number of animals, number of dose levels, and spacing between dose levels. The quality of the modelled endpoints was evaluated according to the following aspects: BMD/BMDL ratio, test for goodness of fit and BMD in the range of dose levels. If one of these aspects was not fulfilled, the BMD derived from this endpoint was considered to be uncertain to some extent and corresponding modelled data sets were examined. The present work demonstrates that the BMD approach is in principle applicable to pesticides, mycotoxins, and natural toxins. Although large differences relating to data availability and data quality were noticed, 69 of 82 modelled endpoints (84%) fulfilled the three quality aspects of BMD modelling.

The interactions in vitro of heavy metals Cd(II), Co(II), Cu(II), Ni(II), Pb(II), and Zn(II) with cytochrome P4501A (CYP1A) induction response and enzyme activity were studied in fish hepatoma cells PLHC-1. Cells were simultaneously exposed to heavy metals and to 3-methylcholanthrene (3-MC), an inducer of CYP1A. Heavy metals were added to the cells in different concentrations. Cytotoxicity were measured in the neutral red (NR) assay, relative CYP1A protein contents in an enzyme-linked immunosorbent assay (ELISA), and CYP1A activities in the ethoxyresorufin-O-deethylase (EROD) assay. All metals had a more pronounced effect on EROD activity than on CYP1A protein content and cytotoxicity. For the most active metal Cd(II), a 50% inhibition of EROD activity was observed at significantly lower concentrations (2.2 x 10(-5) M) than a 50% reduction of CYP1A protein (5.3 x 10(-5) M), and a 50% cytotoxicity (1.4 x 10(-4) M). The inhibitory potency of the metals had the following order: Cd(II) > Ni(II) > Cu(II) > Co(II) = Zn(II) > Pb(II). In a second set of experiments, lysates of 3-MC-induced cells were exposed to heavy metals. Cd(II) and Cu(II) caused a 50% inhibition of EROD activity at significantly lower concentrations than in the experiments with living cells, at 8.2 x 10(-6) M and 1.3 x 10(-5) M, respectively, whereas the effect by Co(II) occurred at a significantly higher concentration (8.2 x 10(-4) M). The results indicate that Cd(II) and Cu(II) in particular may affect the CYP1A system of the liver of fish at low concentrations through direct inhibition of the CYP1A enzyme activity. CYP1A induction response in fish liver is increasingly being used in biomonitoring programs. In the environment, interactions of CYP1A-inducing and CYP1A-inhibiting components (such as heavy metals) can be expected and must be taken into consideration.