New aspects in deriving health-based guidance values for bromate in swimming pool water

Bromate, classified as a EU CLP 1B carcinogen, is a typical by-product of the disinfection of drinking and swimming pool water. The aim of this study was (a) to provide data on the occurrence of bromate in pool water, (b) to re-evaluate the carcinogenic MOA of bromate in the light of existing data, (c) to assess the possible exposure to bromate via swimming pool water and (d) to inform the derivation of cancer risk-related bromate concentrations in swimming pool water. Measurements from monitoring analysis of 229 samples showed bromate concentrations in seawater pools up to 34 mg/L. A comprehensive non-systematic literature search was done and the quality of the studies on genotoxicity and carcinogenicity was assessed by Klimisch criteria (Klimisch et al., Regul Toxicol Pharmacol 25:1–5, 1997) and SciRAP tool (Beronius et al., J Appl Toxicol, 38:1460–1470, 2018) respectively. Benchmark dose (BMD) modeling was performed using the modeling average mode in BMDS 3.1 and PROAST 66.40, 67 and 69 (human cancer BMDL₁₀; EFSA 2017). For exposure assessment, data from a wide range of sources were evaluated for their reliability. Different target groups (infants/toddlers, children and adults) and exposure scenarios (recreational, sport-active swimmers, top athletes) were considered for oral, inhalation and dermal exposure. Exposure was calculated according to the frequency of swimming events and duration in water. For illustration, cancer risk-related bromate concentrations in pool water were calculated for different target groups, taking into account their exposure using the hBMDL₁₀ and a cancer risk of 1 in 100,000. Convincing evidence was obtained from a multitude of studies that bromate induces oxidative DNA damage and acts as a clastogen in vitro and in vivo. Since statistical modeling of the available genotoxicity data is compatible with both linear as well as non-linear dose–response relationships, bromate should be conservatively considered to be a non-threshold carcinogen. BMD modeling with model averaging for renal cancer studies (Kurokawa et al., J Natl. Cancer Inst, 1983 and 1986a; DeAngelo et al., Toxicol Pathol 26:587–594, 1998) resulted in a median hBMDL₁₀ of 0.65 mg bromate/kg body weight (bw) per day. Evaluation of different age and activity groups revealed that top athletes had the highest exposure, followed by sport-active children, sport-active adults, infants and toddlers, children and adults. The predominant route of exposure was oral (73–98%) by swallowing water, followed by the dermal route (2–27%), while the inhalation route was insignificant (< 0.5%). Accepting the same risk level for all population groups resulted in different guidance values due to the large variation in exposure. For example, for an additional risk of 1 in 100,000, the bromate concentrations would range between 0.011 for top athletes, 0.015 for sport-active children and 2.1 mg/L for adults. In conclusion, the present study shows that health risks due to bromate exposure by swimming pool water cannot be excluded and that large differences in risk exist depending on the individual swimming habits and water concentrations.

[Analyses of pesticides in drinking water from small-scale water supplies in Schleswig-Holstein, Germany]

In rural areas of Schleswig-Holstein, Germany, drinking water for about 37 000 people is provided by approximately 10 000 small-scale water supplies. For those wells data on pesticides in the drinking water are rare. In this study 100 small-scale water supplies, mainly situated in areas with intensive agriculture, fruit-growing or tree-nursery, were selected and the drinking water was analysed for pesticides. In 68 samples at least one agent or metabolite was detectable, 38 samples showed multiple contaminations. The metabolites dimethylsulfamide and chloridazone-desphenyl were found in nearly 40% of the wells in concentrations up to 42 µg/L. Bentazone was the most frequently detected biocidal agent. These data show that pesticides in drinking water from small-scale supplies are a notable issue in preventive public health.

Kinetic aspects of the reduction of mercury ions by humic substancesI. Experimental desig

A combination of a computer controlled titration device with a cold vapour atomic absorption spectrometer was set up to examine the kinetics of the reaction between humic substances and Hg(II). Subsequent injections of Hg(II) into an excess of humic acid produce data about short and long term changes in the reaction velocity of humic substances. This experimental design is suitable for the examination of the effects of pH, reaction time, light and interfering substances like chloride on the formation of elemental mercury. The obtained data agree with data from the literature. With the accumulation of the produced elemental mercury on a gold net it is possible to enhance the sensitivity of the method. This enables examinations at environmental concentrations.

[Effects of a coffee-antacid-mixture and a commercial coffee with regard to gastrin, pH and gastric secretion (author's transl)]

The influence of a coffee-antazid-mixture was investigated at 30 patients with diseases of the stomach (17 with duodenal ulcer, 6 with gastric ulcer and 7 with chronic gastritis) in comparison to a commercial coffee. The parameters measured were the gastric basal acid output, the continuous registration of the pH by an intragastric electrode and the serum gastrin concentration before and after the application of the tests substances. 75% of the patients with duodenal ulcer showed a positive effect by means of a greater elevation of the intragastric pH after application of the mixture in comparison to coffee. The effect was strongly correlated to the basal acid ouptput. In the group with gastric ulcer and that with duodenal ulcer under the influence of the mixture the pH after the initial rise decreased to less deeper values. There was a close relationship to the patterns of gastric ulcer as well with chronic gastritis there was an additional facourable effect on the symptoms of abdominal pain which occured after coffee and not after the mixture. The group with chronic gastritis showed no difference between the pure coffee and the coffee-antacid-mixture. A possible relationship of the products of coffee roasting and the adsorptive properties of the antacid is discussed.