Establishing the Association between Blood Levels of Chloroform in Children and Concentrations of Chloroform and Its Derivatives in Drinking Water of Centralized Water Supply Systems

Abstract

Background: Surface reservoirs remain one of the priority sources of drinking water in the Russian Federation whereas the increasing anthropogenic effect on the environment does not exclude the possibility of contamination of surface waters with toxic compounds. The use of traditional methods of water disinfection with active chlorine aggravates the situation and leads to formation of highly toxic organochlorine compounds. In this regard, one of the urgent hygienic problems is to establish health effect of these toxicants in the population including its most sensitive groups. The objective of the study was to establish and quantify the relationship between concentrations of chloroform and its derivatives in drinking water and blood levels of organochlorine compounds in children consuming potable water with a higher content of chlorine and its derivatives. Materials and methods: The study was conducted on six territories of the Perm Region constituting an observation area where drinking water was noncompliant with hygienic standards by a number of indices, and a comparison area. The analysis of trihalomethanes in drinking water samples was carried out in accordance with the requirements of sanitary regulations SanPiN 2.1.4.1074–01. The levels of trihalomethanes (chloroform, carbon tetrachloride, dibromochloromethane, dichlorobromethane, and 1,2-dichloroethane) in children’s blood samples were analyzed by capillary gas chromatography in combination with a specific detector to increase selectivity and sensitivity of determination. We used a Kristall-5000 gas chromatograph with an Optima-5 capillary column (25 m × 0.32 mm × 0.5 μL) and a selective electron capture detector (ECD). Results: The data of comprehensive chemical analyses of average levels of trihalomethanes in blood samples of children consuming drinking water with an increased content of determined compounds (up to 3.5 MPC) and the water complying with hygienic standards are presented. We observed significant differences (р<0.005) between two groups in the blood levels of chloroform, carbon tetrachloride, and 1,2-dichloroethane that were 5.6, 6 and 24 times higher in children of the test group compared to the controls. Conclusion: We revealed a statistically significant causal relationship between the increase in chloroform concentrations in drinking water and the increase in blood levels of chloroform in children described by the equation у=0.00188+0.01782х (R2=0.263, p=0.0018).