Investigating arsenic (As) occurrence and sources in ground, surface, waste and drinking water in northern Mongolia

Elevated levels of arsenic in drinking water are found in several parts of Asia. Prolonged intakes of even low concentrations typically have serious health effects. This research paper integrates results of various studies on arsenic contamination of ground, surface, waste and drinking water in north-central Mongolia. Samples were analyzed with the ARSOlux biosensor and the Arsenator field test kit as well as different spectrometric methods (ICP-MS, ICP-OES). Altogether 309 samples were tested for their arsenic concentration, 44 of them with more than one technique. In the study region, the enrichment of heavy metals in surface waters is often linked to mining and coal combustion. The highest concentration of arsenic (As) was detected in the effluent of a gold mine (up to 2,820 μg L⁻¹) and in the ash basin of a thermal power plant (up to 1,170 μg L⁻¹). Five of 54 drinking water samples and 16 of 184 river samples were found to contain As levels above the World Health Organization (WHO) maximum permissible limit (10 μg L⁻¹), with a maximum of 300 μg L⁻¹As. In addition, elevated levels of uranium were detected. The degree and extent of As concentrations exceeding WHO standards were previously unknown and demonstrate the necessity for a more intensive screening as well as possible interventions concerning the intake of arsenic-contaminated drinking water. Preliminary results indicate that the ARSOlux biosensor technology is well suited for a precise quantification of arsenic content at low detection limits in regions where access to central laboratories is difficult.