Negative impacts exerted by elevated arsenic concentrations in drinking water on biochemical parameters in children living in a specific geochemical province

Introduction. There are geochemical provinces in Russia where refuse heaps from mining enterprises increase a share of water samples from drinking water supply sources that don’t conform to hygienic standards as per their sanitary and chemical parameters, including arsenic concentrations.Material and methods. Our research objects were drinking water samples taken in a specific geochemical province where arsenic concentrations in drinking water were increased and the situation was made even worse by a mill tailing belonging to a closed mining enterprise located there (the test territory). Our reference territory was another geochemical province where arsenic wasn’t detected in drinking water in excess concentrations and where no mill tailings were belonging to similar enterprises. We also took data on risk assessment and examined biological materials taken from children (blood, urine, and hair).Results. Poor quality of drinking water as for arsenic contents caused by specific conditions in a geochemical province and aggravated by a mill tailing belonging to a closed mining enterprise led to unacceptable risks of non-carcinogenic effects (up to 1.83∙10-2) produced on the cardiovascular and hormonal system, as well as on the gastrointestinal tract. Children who had to drink low quality water had arsenic in their blood, urine, and hair in concentrations which were up to 264 times higher than those in blood, urine, and hair of children from the reference group. Children who had elevated arsenic concentrations in urine (starting from 0.295 µg/ml), blood (starting from 0.006 µg/ml), and hair (starting from 14.59 µg/ml) had their laboratory test indices deviating from those in children from the reference group. Thus, aspartate aminotransferase (AST) and creatinine concentrations in blood serum were 1.2-1.3 times higher than in the reference group. A contribution made by arsenic into biochemical indices deviating from the physiological standards varied from 16% to 97%.Conclusions. Geochemical provinces with excess arsenic concentrations and mill tailings belonging to mining enterprises, either closed or operating, require special attention. It is necessary to accomplish medical and preventive activities aimed at minimizing health risks; take into account peculiarities related to how this element accumulates in a body and detected negative changes in biochemical parameters.

Preliminary results of spatial distribution of uranium and thorium in soil profiles near a uranium industrial site, Guangdong province, China

Four soil profiles were collected from locations with different distances (5, 50, 250 and 1000 m) from a uranium mill tailings dam, Guangdong province, China, to investigate the pollution status of the soil in mining/milling-related areas based on the contents of uranium (U) and thorium (Th), thus to understand the impacts of uranium industrial activities to the surroundings. The U and Th concentrations were determined by inductively coupled plasma mass spectrometry (ICP-MS) after conventional HF-HNO3-HClO4 digestion procedures. The results indicate that the soils within 50 m from uranium tailing were severely contaminated; those in 250 and 1000 m soil samples were observed to be with local background level even though these in 250 m had slightly higher U/Th ratios. Uranium concentrations varied from 5.50 ± 0.27 to 160.55 ± 8.03 mg/kg, with maximum values recorded in an intermediate layer of the 5-m distance soil profile. In comparison, the concentration of Th ranged from 6.02 ± 0.30 to 84.71 ± 4.24 mg/kg, with maximum values observed in the top layer of the 1000-m distance soil profile. The U/Th ratio varied from 0.15 to 11.99 compared with 0.20, 0.22 and 0.26 of the average for Guangdong province, national China and the world, respectively. The mean U/Th of four soil profiles showed a reduction with distance from the uranium mill tailing dam, suggesting the relatively large magnitude of uranium elevation in soils within limited distances.