Factors and population health risks under exposure to components detected in drinking water within natural hydrogeochemical provinces in Perm region

Our research goal was to assess health risks for population who consumed drinking water with specific chemical structure systematically and for a long time. Drinking water quality is determined by conditions existing in hydrogeochemical provinces where rocks and soils contain increased concentrations of such hazardous metals as chromium, nickel, lead, manganese, and iron. We showed that low frequency or even absence of non-conformity to hygienic standards for admixtures in drinking water doesn't fully guarantee its safety in complicated hydrogeochemical conditions. When certain carcinogenic admixtures (cadmium, chromium, nickel, arsenic, and lead) occur together in drinking water even in low concentrations, it can cause unacceptable population health risks. Drinking water taken in examined geochemical provinces in Perm region causes individual lifelong carcinogenic risk which is (under the worst exposure scenarios) equal to 4*10-3. It can be ranked as De manifestis Risk and requires immediate measures to be taken by those responsible to reduce it. Unacceptable non-carcinogenic risks are caused by joint concentrations of arsenic, strontium, and some other compounds in drinking water. The highest risks existing on the examined territories were detected in relation to gastrointestinal tract diseases (HI up to 10.9, basic risk factor is chromium and its compounds), musculoskeletal system diseases (HI up to 11.8, strontium as a basic factor), and central nervous system diseases (HI up to 11.8, basic factors are arsenic, manganese, and lead). Contributions made by various elements into overall risks were different in different provinces. In some cases, when a certain element occurs in the crust in hazardous concentrations, its contents in drinking water are not observed. We recommend organizations that deal with water supply and sanitary surveillance bodies to take into account peculiarities of a geochemical province and to include admixtures that are contained in the environment in high quantities into monitoring programs and laboratory research