Thorsten Stahl

Antigenotoxic properties of Eruca sativa (rocket plant), erucin and erysolin in human hepatoma (HepG2) cells towards benzo(a)pyrene and their mode of action.

In recent years, rocket plant (Eruca sativa) has gained greater importance as a vegetable and spice, especially among Europeans. E. sativa is a member of the Brassicaceae, which is considered to be an important chemopreventive plant family. In the present study, we assessed the chemopreventive potency and underlying mechanisms of extracts of E. sativa in HepG2 cells. No genotoxic effect could be observed in HepG2 cells treated with up to 50 microl/ml plant juice for 24 h when using the comet assay. In antigenotoxicity experiments, E. sativa extract reduced the benzo(a)pyrene-induced genotoxicity in a U-shaped manner. This effect was accompanied by a significant induction of glutathione S-transferase. No significant suppression of B(a)P-induced CYP1A1 protein expression or enzyme activity could be observed. Chemical analysis of the plant material by gas chromatography identified the isothiocyanates erucin, sulforaphane, erysolin and phenylethyl isothiocyanate. Results derived with the single ITC compounds support the assumption that their synergistic interaction is responsible for the strong antigenotoxicity of the plant material. The present study provided an assessment of the bioactive effects of rocket plant extract in a human cell culture system. This could help to evaluate the balance between beneficial vs. possible adverse effects of rocket plant consumption.

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 publishers online edition of Journal of Environmental Science and Health, Part A to view the supplemental file.

Aluminium content of selected foods and food products

For many years aluminium was not considered harmful to human health because of its relatively low bioavailability. In 1965, however, animal experiments suggested a possible connection between aluminium and Alzheimers disease.Oral intake of foodstuffs would appear to be the most important source of aluminium. Consequently, the joint FAO/WHO Expert Committee on Food Additives reduced the provisional tolerable weekly intake value for aluminium from 7 mg kg-1 body weight/week to 1 mg kg-1 body weight/week. Analysis of aluminium content of a number of foods and food products was therefore undertaken in order to evaluate the nutritional intake of aluminium.A total of 1,431 samples were analysed within the scope of this study. The data obtained allow a preliminary but current depiction of the aluminium content of selected non-animal foods, food products and beverages.

Isothiocyanate concentration in Kohlrabi (Brassica oleracea L. Var. gongylodes) plants as influenced by sulfur and nitrogen supply.

Glucosinolates (GSss) represent bioactive compounds of Brassica vegetables whose health-promoting effects merely stem from their breakdown products, particularly the isothiocyanates (ITCs), released after hydrolysis of GSs by myrosinase. GSs are occasionally discussed as transient S reservoirs, but little is known concerning the interactive effect of S and N supply on ITC concentrations. Therefore, kohlrabi plants were grown in a pot experiment with varied S (0.00, 0.05, and 0.20 g pot (-1)) and N (1, 2, and 4 g pot (-1)) supplies. Plant growth exhibited a classical nutrient response curve with respect to both S and N. The ITC profile of kohlrabi tubers was dominated by methylthiobutyl ITC (11-1350 micromol (g DM) (-1)), followed by sulforaphan (7-120 micromol (g DM) (-1)), phenylethyl ITC (5-34 micromol (g DM) (-1)), and allyl ITC (5-38 micromol (g DM) (-1)), resulting from the hydrolysis of glucoerucin, glucoraphanin, gluconasturtiin, and sinigrin, respectively. The ITC profile was in agreement with reported data, and concentrations of all ITCs were substantially reduced in response to increasing N and decreasing S supply. A growth-induced dilution effect could be ruled out in most cases, and the results do not support the hypothesis that GS acts as transient reservoir with respect to S.

Interactive effects of sulfur and nitrogen supply on the concentration of sinigrin and allyl isothiocyanate in Indian mustard (Brassica juncea L.).

Food derived from Brassica species is rich in glucosinolates. Hydrolysis of these compounds by myrosinase yields isothiocyanates and other breakdown products, which due to their pungency represent the primary purpose of Indian mustard cultivation. Strong interactive effects of S (0.0, 0.2, and 0.6 g pot(-1)) and N (1, 2, and 4 g pot(-1)) supply on growth, seed yield, and the concentrations of glucosinolates and isothiocyanates in seeds were observed in growth experiments, reflecting the involvement of S-containing amino acids in both protein and glucosinolate synthesis. At intermediate S supply, a strong N-induced S limitation was apparent, resulting in high concentrations of sinigrin (12 micromol g(-1) of DM) and allyl isothiocyanate (213 micromol kg(-1) of DM) at low N supply only. Myrosinase activity in seeds increased under low N and low S supply, but the results do not suggest that sinigrin functions as a transient reservoir for S.

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.

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.

Pathways and factors for food safety and food security at PFOS contaminated sites within a problem based learning approach.

Perfluorooctanesulfonic acid (PFOS) and related substances have been listed in Annex B of the Stockholm Convention. The implementation requires inventories of use, stockpiles, and environmental contamination including contaminated sites and measures for (risk) reduction and phase out. In most countries monitoring capacity is not available and therefore other approaches for assessment of contaminated sites are needed. Available informations about PFOS contamination in hot spot areas and its bio-accumulation in the food webs have been merged to build up a worst-case scenario We model PFOS transfer from 1 to 100ngL(-1) range in water to extensive and free-range food producing animals, also via the spread of contaminated sludges on agriculture soils. The modeling indicates that forages represented 78% of the exposure in ruminants, while soil accounted for >80% in outdoor poultry/eggs and pigs. From the carry-over rates derived from literature, in pork liver, egg, and feral fish computed concentration falls at 101, 28 and 2.7ngg(-1), respectively, under the 1ngL(-1) PFOS scenario. Assuming a major consumption of food produced from a contaminated area, advisories on egg and fish, supported by good agriculture/farming practices could abate 75% of the human food intake. Such advisories would allow people to become resilient in a PFOS contaminated area through an empowerment of the food choices, bringing the alimentary exposure toward the current Tolerable Daily Intake (TDI) of 150ngkg(-1)bodyweightd(-1) proposed by the European Food Safety Authority (EFSA).

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.