Levels, accumulation patterns and retrospective trends of perfluoroalkyl acids (PFAAs) in terrestrial ecosystems over the last three decades.

As a result of their ubiquitous presence in the environment perfluoroalkyl acids (PFAAs) have been demonstrated in numerous organisms worldwide, in particular in those of higher trophic levels. The fact that PFAAs have been detected in various human matrices, together with the resultant potential human health risks, knowledge of possible paths of entry and distribution in various ecosystems, is of great importance. In this context pooled samples of terrestrial ecosystems - roe deer liver (n = 141), earthworms (n = 44) as well as leaves from beech and poplar trees (n = 70) - from the year 1989-2015 were obtained from the German Environmental Specimen Bank and examined for the presence of 11 PFAAs for the first time. In addition to determining individual and total PFAA concentrations, temporal trends have been deduced in order to determine the effectiveness of regulatory measures. The highest total mean concentration of PFAAs (sum of the concentrations of the 11 analytes) were 9.9 µg/kg in the roe deer liver samples, followed by earthworm samples with a mean PFAA concentration of 3.5 µg/kg and leaves with a mean total concentration of 2.5 µg/kg. In regard to temporal trends there was a significant reduction of concentrations for perfluorooctane sulfonate, perfluorooctanoic acid, perfluorononanoic acid and perfluorodecanoic acid in roe deer liver from 2003 to 2015, an indication of the effectiveness of regulatory measures. The same is true for the perfluorooctane sulfonate concentrations in earthworms and for perfluorooctanoic acid concentrations in the leaves. In contrast, an increase in perfluorobutanoic acid concentrations was observed from 2003 to 2015 in all three matrices. In summary it must be noted that in spite of the discernible effectiveness of minimization strategies, PFAAs are still detectable in terrestrial matrices and concentrations of other PFAAs as perfluorobutanoic acid appear to be increasing.

Determination of adsorbable organically bound fluorine (AOF) and adsorbable organically bound halogens as sum parameters in aqueous environmental samples using combustion ion chromatography (CIC).

Because of their toxicity and biomagnification potential individual perfluoroalkyl and polyfluoroalkyl substances (PFAS) are regularly examined in food and environmental matrices by LC-MS/MS. The combustion ion chromatography (CIC) can be used to determine adsorbable organic fluorine (AOF) in aqueous samples. This report describes the optimization and validation of an automated, robust, cost-efficient and rapid CIC method for the determination of AOF. The analysis of 25 fluorinated organic reference substances was performed with recoveries between 16% and 121%. Water from selected surface waters (n = 74), municipal (n = 116) and industrial wastewaters (n = 33) as well as ground water (n = 93) were analyzed by means of CIC. The AOF values of surface water varied between 2.3 and 24.5 µg/L. The concentrations of AOF in 85% of the wastewater discharges were between 2.0 and 8.5 µg/L, while 15% of the samples were below the limit of quantitation (LOQ = 2 µg/L AOF). In 56% of the ground water samples the values were below the LOQ. In 44% of the surface water samples (n = 41) the values were between 2.0 and 6.1 µg/L AOF. CIC analysis was performed in 22 samples from a chemical company wastewater treatment plant, and 14 individual PFAS were determined by LC-MS/MS. AOF values up to 555 µg/L were found in these samples while the total of the individual PFAS, calculated as fluorine, was 8.8 µg/L. This provides evidence, that CIC covers a huge range of fluoroorganic compounds that are presently not detected by LC-MS/MS. Furthermore, the CIC method allowed the determination of four halogens in 26 surface water samples. This demonstrated that the CIC technique can be used as a powerful screening test to support LC-MS/MS methods, and is also useful to detect organic chlorine, bromine and iodine compounds (AOCl, AOBr and AOI).

Concentrations and Distribution Patterns of Perfluoroalkyl Acids in Sewage Sludge and in Biowaste in Hesse, Germany.

A total of 201 sewage sludge and 45 biowaste samples were examined for 14 different perfluoroalkyl acids (PFAA). For perfluorooctanesulfonic acid, maximum concentrations of 698 µg/kg dry weight were measured in sewage sludge and for perfluorohexanesulfonic acid 29.0 µg/kg dry weight were found in biowaste. Looking at the fingerprints of both these matrixes it can be see that long-chain PFAA make up 85.9% of the total concentration in sewage sludge whereas short-chain PFAA only account for 14.1%. In contrast, the trend in biowaste is just the opposite, with 53.2% long-chain and 46.8% short-chain PFAA. These results lead to the conclusion that sewage sludge functions as a sink for long-chain PFAA, and the plants preferentially take up short-chain PFAA from the sludge/soil, as seen by the concentrations found in biowaste. It can be calculated that the total yearly amount of PFAA spread onto agricultural lands amount to 15.3 kg.

Migration of aluminum from food contact materials to food-a health risk for consumers? Part III of III: migration of aluminum to food from camping dishes and utensils made of aluminum.

BACKGROUND: When cooking on a barbecue grill, consumers often use aluminum grill pans. For one, the pan catches the fats and oils that would drip into the embers causing the formation of potentially noxious smoke, and the pan also protects the food from being burned by direct heat from the coals. In addition, new aluminum products for use in ovens and grills are becoming increasingly popular. Due to their light weight and excellent heat transfer camping, utensils made of aluminum are, for example, often used by fishermen and mountain climbers. Preparing food in aluminum utensils can, however, result in migration of the aluminum to the foodstuffs. RESULTS/CONCLUSIONS: In this study presented here, it was found that the transfer limit of 5.00 mg/L for aluminum is not exceeded using simulants for oil or for tap water; however, with an aqueous solution of 0.5% citric acid, the limit is clearly exceeded at 638 mg/L. This means that the Tolerable Weekly Intake (TWI) is exceeded by 298% for a child weighing 15 kg and for an adult weighing 70 kg it is equivalent to 63.8% of the TWI, assuming a daily uptake of 10 mL marinade containing lemon juice over a period of 1 week. Preparation of a fish dish with a marinade containing lemon juice in camping dishes would result in the TWI being exceeded by 871% for a child weighing 15 kg and by 187% for an adult weighing 70 kg assuming a daily uptake of 250 g over a period of 1 week.

Migration of aluminum from food contact materials to food-a health risk for consumers? Part II of III: migration of aluminum from drinking bottles and moka pots made of aluminum to beverages.

BACKGROUND: Drinking bottles and stove-top moka pots made of aluminum have become very popular. Storing drinks in bottles and preparing coffee in a moka pot may result in the migration of aluminum to the beverage. RESULTS/CONCLUSIONS: In a systematic study of aluminum drinking bottles, it has been shown that drinking a mixture of apple juice and mineral water in an aluminum bottle may reach 86.6% of the total weekly intake (TWI) for adults, and drinking tea from an aluminum bottle may exceed the TWI (145%) for a child weighing 15 kg. In contrast, preparing coffee in an aluminum moka pot results in a maximum of 4% to TWI, if an average of 3.17 L coffee is consumed per week, even if the pots are washed in the dishwasher, against the explicit instructions of the manufacturer.

Migration of aluminum from food contact materials to food-a health risk for consumers? Part I of III: exposure to aluminum, release of aluminum, tolerable weekly intake (TWI), toxicological effects of aluminum, study design, and methods.

BACKGROUND: In spite of the prevalence of aluminum in nature, no organism has been found to date which requires this element for its biological functions. The possible health risks to human beings resulting from uptake of aluminum include detrimental effects to the hemopoietic system, the nervous system and bones. Aluminum is used in many fields and occurs in numerous foodstuffs. Food contact materials containing aluminum represent an anthropogenic source of dietary aluminum. RESULTS: As a result of their frequent use in private households a study was undertaken to detect migration of this metal to foodstuffs from drink containers, coffee pots, grill pans, and camping cookware made of aluminum. CONCLUSIONS: An estimate of the health risk to consumers is calculated, based on the tolerable weekly intake (TWI) specified by the European Food Safety Authority of 1 mg/kg body weight for all groups of people. In some instances the TWI is significantly exceeded, dependent upon the food contact material and the food itself.

Transformation of Sulfonamides and Tetracyclines during Anaerobic Fermentation of Liquid Manure.

Liquid manure is frequently used as soil fertilizer due to its high nutrient content. It can also contain residues of pharmaceuticals, such as antibiotics, if farm animals are medicated. The anaerobic fermentation process in biogas plants is discussed as one way to reduce the input of antibiotics into the environment. Therefore, 10 worldwide-applied sulfonamides (sulfachloropyridazine, sulfadiazine, sulfadimethoxine, sulfaguanidine, sulfamerazine, sulfamethazine, sulfamethoxazole, sulfamethoxypyridazine, sulfapyridine, and sulfathiazole) and four frequently used tetracyclines (chlortetracycline, doxycycline, oxytetracycline, and tetracycline) were investigated concerning their elimination pattern during anaerobic fermentation. Batch fermenters with autoclaved and non-autoclaved inoculum were utilized to distinguish between biotic and abiotic elimination pathways. Overall, sulfadimethoxine, sulfamethoxypyridazine, and sulfamethoxazole showed the highest elimination, which was considerably reduced by autoclaving before inoculation. Structure elucidation via nuclear magnetic resonance and different mass spectrometry techniques revealed only minor structural modifications such as O-demethylation and hydrogenation, which did not result in a considerably reduced antimicrobial activity. These results show that, especially, sulfonamides are more persistent than expected. Future studies should deal with the elucidation of relevant process parameters for an enhanced compound degradation.

Method development towards qualitative and semi-quantitative analysis of multiple pesticides from food surfaces and extracts by desorption electrospray ionization mass spectrometry as a preselective tool for food control.

Direct analysis of fruit and vegetable surfaces is an important tool for in situ detection of food contaminants such as pesticides. We tested three different ways to prepare samples for the qualitative desorption electrospray ionization mass spectrometry (DESI-MS) analysis of 32 pesticides found on nine authentic fruits collected from food control. Best recovery rates for topically applied pesticides (88%) were found by analyzing the surface of a glass slide which had been rubbed against the surface of the food. Pesticide concentration in all samples was at or below the maximum residue level allowed. In addition to the high sensitivity of the method for qualitative analysis, quantitative or, at least, semi-quantitative information is needed in food control. We developed a DESI-MS method for the simultaneous determination of linear calibration curves of multiple pesticides of the same chemical class using normalization to one internal standard (ISTD). The method was first optimized for food extracts and subsequently evaluated for the quantification of pesticides in three authentic food extracts. Next, pesticides and the ISTD were applied directly onto food surfaces, and the corresponding calibration curves were obtained. The determination of linear calibration curves was still feasible, as demonstrated for three different food surfaces. This proof-of-principle method was used to simultaneously quantify two pesticides on an authentic sample, showing that the method developed could serve as a fast and simple preselective tool for disclosure of pesticide regulation violations. Graphical Abstract Multiple pesticide residues were detected and quantified in-situ from an authentic set of food items and extracts in a proof of principle study.

Perfluoroalkyl Acid Concentrations in Livers of Fox (Vulpes vulpes) and Chamois (Rupicapra rupicapra) from Germany and Austria.

The concentrations of 11 perfluorinated alkyl acids (PFAAs) were measured in the livers of foxes (Vulpes vulpes) from Germany, a primarily carnivorous species, and chamois (Rupicapra rupicapra) from Austria, an herbivorous species. Perfluorooctanesulfonate (PFOS) at concentrations [all results refer to wet weight (ww)] of 3.2-320 µg/kg were detected in all 40 fox livers tested, yielding an arithmetic mean of 46.6 µg/kg and a median of 29.8 µg/kg. Long-chain PFAAs were detected at concentrations of 1.7 µg/kg perfluorononanoic acid (PFNA) to 2.4 µg/kg perfluorodecanoic acid (PFDA) and perfluorododecanoic acid (PFDoDA). Of the short-chain PFAAs tested, only perfluorohexanoic acid (PFHxA) was found in 1 fox liver at a concentration of 1.4 µg/kg, and perfluorohexane sulfonate (PFHxS) was found in 2 fox livers at a concentration of 1 µg/kg each. PFOS and PFNA concentrations higher than limit of quantification (LOQ) were detected in 90.9 and 81.8 % of chamois livers, respectively. The arithmetic mean for PFOS concentrations was 2.2 µg/kg (median 2.4 µg/kg), a factor of 21 (median factor of 12) lower than in fox livers. The arithmetic mean for PFNA concentrations was 2.0 µg/kg (median 1.9 µg/kg). Perfluorobutanoic acid, PFHxA, perfluorooctanoic acid, perfluorobutanesulfonate, and PFHxS were not detected at concentrations higher than the LOQ in any of the samples. The various results are compared with one another and with the results of other studies of herbivorous, carnivorous, and omnivorous wild animals. The highest concentrations of PFAA, in particular PFOS, were found in omnivorous animals followed by carnivores. The lowest levels were present in herbivores.

Spatially resolved investigation of systemic and contact pesticides in plant material by desorption electrospray ionization mass spectrometry imaging (DESI-MSI).

Distribution of pesticides both on the surface of leaves and in cross sections of plant stem and leaves was investigated using desorption electrospray ionization mass spectrometry imaging (DESI-MSI) with a spatial resolution of 50-100 µm. Two commercially available insecticide sprays containing different contact pesticides were applied onto leaves of Cotoneaster horizontalis, and the distributions of all active ingredients were directly analyzed. The first spray contained pyrethrins and rapeseed oil, both known as natural insecticides. Each component showed an inhomogeneous spreading throughout the leaf, based on substance polarity and solubility. The second spray contained the synthetic insecticides imidacloprid and methiocarb. Imidacloprid accumulated on the border of the leaf, while methiocarb was distributed more homogenously. In order to investigate the incorporation of a systemically acting pesticide into Kalanchoe blossfeldiana, a commercially available insecticide tablet containing dimethoate was spiked to the soil of the plant. Cross sections of the stem and leaf were obtained 25 and 60 days after application. Dimethoate was mainly detected in the transport system of the plant after 25 days, while it was found to be homogenously distributed in a leaf section after 60 days.

Accumulation potentials of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) in maize (Zea mays).

Uptake of perfluoroalkyl acids (PFAAs) by maize represents a potential source of exposure for humans, either directly or indirectly via feed for animals raised for human consumption. The aim of the following study was, therefore, to determine the accumulation potential of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) in maize (Zea mays). Two different concentrations of PFAAs were applied as aqueous solution to the soil to attain target concentrations of 0.25 mg or 1.00 mg of PFAA per kg of soil. Maize was grown in pots, and after harvesting, PFAA concentrations were measured in the straw and kernels of maize. PFCA and PFSA concentrations of straw decreased significantly with increasing chain length. In maize kernels, only PFCAs with a chain length ≤ C8 as well as perfluorobutanesulfonic acid (PFBS) were detected. The highest soil-to-plant transfer for both straw and kernels was determined for short-chained PFCAs and PFSAs.

Tissue specific uptake and elimination of perfluoroalkyl acids (PFAAs) in adult rainbow trout (Oncorhynchus mykiss) after dietary exposure.

Tissue specific uptake and elimination of perfluoroalkyl acids (PFAAs) were studied in rainbow trout (Oncorhynchus mykiss). Adult trout were exposed to perfluorobutane sulfonic acid (PFBS), perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) via food over a time period of 28d. In the following 28-d depuration period the fish were fed PFAA-free food. At defined sampling times four animals were removed from the experimental tank, euthanized and dissected. Muscle, liver, kidneys, gills, blood, skin and carcass were examined individually. At the end of the accumulation phase between 0.63% (PFOA) and 15.5% (PFOS) of the absolute, applied quantity of PFAAs was recovered in the whole fish. The main target organ was the liver with recovery rates between 0.11% (PFBS) and 4.01% (PFOS) of the total amount of ingested PFAAs. Perfluoroalkyl sulfonic acids were taken up more readily and had longer estimated elimination half-lives than perfluoroalkyl carboxylic acids of the same chain length. The longest estimated elimination half-lives were found to be for PFOS between 8.4d in muscle tissue and 20.4d in the liver and for PFNA between 8.2d in the blood and 11.6d in the liver.

Effects of chain length and pH on the uptake and distribution of perfluoroalkyl substances in maize (Zea mays).

Maize is the most important grain crop grown for human nutrition, animal fodder and biogas production worldwide. Nonetheless, no systematic studies have been undertaken on these plants to examine the uptake mechanisms for perfluoroalkyl substances (PFASs) dependent upon chain length and pH value. The aim of the present study was therefore to determine the influence of chain length (C4 to C10) and pH value (pH 5, pH 6, pH 7) on the uptake and distribution of seven perfluoroalkyl carboxylic acids (PFCAs) and three perfluoroalkane sulfonic acids (PFSAs) by maize in nutrient solution experiments under controlled conditions in a climate chamber. A pH-dependent uptake was observed for perfluorodecanoic acid (PFDA) with an uptake rate of 2.51 µg g(-1) at pH 5 compared to 1.52 µg g(-1) root dry weight (DW) per day (d) at pH 7. Perfluorobutanoic acid (PFBA) had the highest uptake rate within the group of PFCAs with an average of 2.46 µg g(-1) root DWd(-1) and perfluorooctane sulfonic acid (PFOS) had the highest uptake rate (3.63 µg g(-1) root DWd(-1)) within the group of PFSAs. The shoot:root ratio for shorter-chain PFCAs (≤ C7) and PFBS (C4) was >2.0, which indicates that shorter-chain PFASs are transferred predominantly and at higher concentrations to the shoot. In contrast, long-chain PFCAs such as perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) as well as the PFASs perfluorohexane sulfonic acid (PFHxS) and perfluorooctane sulfonic acid (PFOS) accumulated at higher concentrations in the roots of maize plants with a shoot:root ratio of <1.0.

Long-term lysimeter experiment to investigate the leaching of perfluoroalkyl substances (PFASs) and the carry-over from soil to plants: results of a pilot study.

To study the behavior of perfluoroalkyl substances (PFASs) in soil and the carry-over from soil to plants, technical mixtures of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) at a concentration of 25 mg/kg soil were applied to 1.5 m(3) monolithic soil columns of a lysimeter. Growth samples and percolated water were analyzed for PFASs throughout a period of 5 years. In addition to PFOA/PFOS plant compartments and leachate were found to be contaminated with short-chain PFASs. Calculation showed significant decreasing trends (p < 0.05) for all substances tested in the growth samples. Short-chain PFASs and PFOA pass through the soil much more quickly than PFOS. Of the 360 g of PFOA and 367.5 g of PFOS applied to the soil, 96.88% PFOA and 99.98% PFOS were still present in the soil plot of the lysimeter after a period of 5 years. Plants accumulated 0.001% PFOA and 0.004% PFOS. Loss from the soil plot through leachate amounted to 3.12% for PFOA and 0.013% for PFOS.

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) in mineral water and tap water.

The aims of the present study were to determine PFAS (perfluoroalkyl and polyfluoroalkyl substances) concentrations in various sources of water intended for human consumption, use these data to calculate the possible uptake via water as well as to estimate the water related health risk to consumers. A total of 177 water samples (119 mineral waters, 26 tap water samples, 18 spring water samples and 14 raw (untreated) water samples) were analyzed using liquid chromatography tandem mass spectrometry for the presence of 10 or 19 PFASs, respectively. PFAS concentrations above the limit of detection of 1 ng/L were found in 52% of all samples. Short-chain PFASs with less than 8 carbon atoms were responsible for 58% of the total PFAS contamination. The highest concentration (sum of PFASs) of 42.7 ng/L was detected in tap water. The calculated maximum uptake of both components for which a tolerable daily intake (TDI) level exists were 0.17 ng/kg bodyweight/day for PFOS (perfluorooctane sulfonic acid) and 0.21 ng/kg bodyweight/day for PFOA (perfluorooctane carboxylic acid). In regard to the model calculations made here (TDI for adults and for infants), the uptake of PFOS and PFOA via consumption of water can be considered negligible. Supplemental materials are available for this article. Go to the publisher's online edition of Journal of Environmental Science and Health, Part A to view the supplemental file.

Temporal and spatial trends of perfluoroalkyl substances in liver of roe deer (Capreolus capreolus).

For more than 50 years perfluoroalkyl substances (PFASs) have found worldwide industrial and household uses. Some PFASs are presumed to be persistent and bioaccumulative. Roe deer (Capreolus capreolus) are thought to be a suitable bioindicator for the accumulation of organic xenobiotics. Due to the ubiquitous nature of PFASs in the environment a retrospective study on temporal trends was carried out. A total of 110 deer liver pools collected from 1989 to 2010 in Germany were analyzed for their levels of PFASs. The highest concentrations were measured for perfluorooctane sulfonate (PFOS) (median 6.3 µg/kg). Perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were detected with median concentrations of 0.5 µg/kg, 1.2 µg/kg and 0.3 µg/kg, respectively, while concentrations of the other PFASs were below the limit of quantification. PFOS concentrations decreased significantly (r(s) = -0.741; p = <0.0001) from 9.2 µg/kg in 2000 to 1.8 µg/kg in 2010.

Assessment of the DNA damaging potency and chemopreventive effects towards BaP-induced genotoxicity in human derived cells by Monimiastrum globosum, an endemic Mauritian plant.

Naturally occurring compounds have protective effects towards mutagens and carcinogens. The leaf extract of Monimiastrum globosum (Bois de Clous), a Mauritian endemic plant from the Myrtaceae family, was studied for its potency to induce DNA damage in human HepG2 hepatoma cells using DNA migration as a biological endpoint in the alkaline single cell gel electrophoresis (SCGE) assay. This was contrasted with the ability to modulate the benzo[a]pyrene (BaP)-dependent DNA damage in human hepatoma cells. M. globosum caused genotoxicity in HepG2 cells at concentrations exceeding 3mg fresh weight (FW) per ml cell culture in the absence of cytotoxicity. Pre-treatment of the cells with 12.2 microg FW/ml to 1.56 mg FW/ml led to a pronounced antigenotoxic effect towards BaP-induced DNA damage. DNA migration (OTM) was reduced by 66%, 81.5% and 74% for 49, 98 and 195 microg FW/ml, respectively. A U-shaped dose-response curve was derived for M. globosum indicating genotoxic effects in high doses and antigenotoxic effects in low doses. M. globosum extract had total phenolics (15 mg/g FW) with flavonoids (aglycones and conjugates: 8 mg/g FW) and proanthocyanidins (3mg/g FW) as major phenolic subclasses. The hydrolysis of conjugated flavonoids yielded the aglycones quercetin (606 microg/g FW) and kaempferol (117.8 microg/g FW) while HPLC-MS/MS analysis of the total extract revealed free flavonoids such as quercetin (19.2 microg/g FW) and myricetin (2.5 microg/g FW). The antioxidant activity of the extract of M. globosum, assessed by the FRAP and TEAC assays yielded values of 275+/-3.82 micromol/g FW and 346+/-4.2 micromol/g FW, respectively.

Extract of Toxicodendron quercifolium caused genotoxicity and antigenotoxicity in bone marrow cells of CD1 mice.

As has been shown in numerous studies, naturally occurring compounds can have protective effects towards mutagens and carcinogens. In the present study, the genotoxic/antigenotoxic effect of Toxicodendron quercifolium (poison ivy) extract, which has been identified as antigenotoxic in human HepG2 cells in former studies, was examined in the in vivo micronucleus assay using polychromatic erythrocytes (PCE) of bone marrow of CD1-mice. For this, D0 (1:10), D0 (1:25), D0 (1:50), D1 (1:50), D2 (1:50), and D4 (1:50) dilutions of ethanolic plant extract prepared on the basis of the "Hömoopathisches Arzneimittelbuch (HAB 2000)" were administered orally to CD1 mice over a period of two days. A significant increase (p < 0.05) in micronucleus frequencies was found after administration of D0 (1:10), the highest tolerated dose. Additionally, antigenotoxic effects of T. quercifolium towards benzo(a)pyrene-induced micronucleus formation were studied. For that, four dilutions of the plant extract [D0, D2, D4, D6, each 1:50] were administered orally to CD1 mice for five days prior to the administration of benzo(a)pyrene (250 mg/kg b.w.) for another two days. It was found that the administration of the dilutions D0 (1:50) and D2 (1:50) of T. quercifolium extract significantly inhibited benzo(a)pyrene-induced micronucleus formation (p < 0.0001). The results of this study indicated that T. quercifolium extract has the character of a so-called "Janus"-genotoxin: High doses led to a weak but significant increase of micronucleus frequencies whereas low doses showed chemopreventive effects towards benzo(a)pyrene-induced DNA damage. The constituents of T. quercifolium responsible for the genotoxic and antigenotoxic effects may be flavonoids, which are known to have prooxidative and scavenging effects and identified by HPLC-MS/MS.

Development of an immuno-immobilized androgen receptor assay (IRA) and its application for the characterization of the receptor binding affinity of different pesticides.

Pesticides are synthetic chemicals used not only for improving food and feed production but also for the protection of materials and of human health and well-being. Some of these substances are suspected for adverse effects attributable to an interaction with the endocrine system of vertebrates by mimicking or inhibiting endogenous hormones. One of the biological targets important in this relation is the androgen receptor (AR). To be able to screen environmental samples for the presence of compounds which might interfere with androgen action, we aimed to develop a receptor assay based on recombinant human AR (rhAR). We herein describe an rhAR assay in which the receptor is immobilized in microtiter plates via a specific antibody. The assay can be used for high throughput screening of chemicals spread into the environment. 29 of the most recommended pesticides of the Federal Country Hessen, Germany, were tested for their ability to displace [3H]-DHT bound to the rhAR. This evaluation included the major part of the most common herbicides, insecticides and fungicides and covered three potential groups of endocrine disrupting chemicals. For 28 of the substances evaluated, the relative binding affinity to the rhAR was below 0.1% when compared to dihydrotestosterone (DHT) (100%), only fentinacetate exhibited an affinity of 1.42%. An exchange assay indicated that the binding inhibition was reversible. In consequence, fentinacetate seems to be a hormonally active substance which may be present in vegetables or fish, but also on clothing. We conclude that further investigations on this compound and its metabolites are necessary.