[Analysis of factors resulting in anomalous arsenic concentration in groundwaters of Shanyin, Shanxi province].

The chemical characteristics of groundwaters containing anomalous arsenic were summarized and the factors influencing arsenic enrichment in groundwater were discussed in this paper, based on chemical data of general compositions, trace elements and organic matters of sixty-six groundwaters and mineral analysis of thirty aquifer matrix. The main factors inducing anomalous arsenic in groundwaters included high pH (8.09), high concentrations of phosphate (0.71 mg/L) and organic matters (5.14 mg/L), and anoxic environment. High pH, high phosphate content and anoxic environment made against adsorption of As into aquifer which contains clay minerals. And high concentration of organic matters promoted the activity of As in groundwater system. These factors contribute to desorption and transportation of As in aquifers.