Hydrochemical characteristics and a health risk assessment of the use of river water and groundwater as drinking sources in a rural area in Jiangjin District, China

To determine the hydrochemical characteristics and health risks associated with their use as drinking water, 54 river water and 44 groundwater samples were collected and analyzed in a rural area of Jiangjin District, Chongqing City. The concentration of solutes in river water and groundwater showed significant spatial variability in the region. A number of dissolved chemical constituents including nitrate (NO3−), nitrite (NO2−), aluminum (Al), arsenic (As), boron (B), barium (Ba), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb) and selenium (Se) exceeded their respective recommended drinking water limits at some locations. Ternary plots of cations, anions and silica indicated that carbonate weathering was the primary source of major ions in water, followed by silicate weathering. Elevated concentrations of some chemical constituents including NO3− and chloride (Cl−) were found in water samples in areas with the most intensive agricultural land use activities. A health risk assessment indicated that Cl− and NO3− were the most important chemical constituents that were a non-carcinogenic health concern. A carcinogenic health risk assessment indicated that chromium (Cr) and As were the chemical constituents of most concern in water from the area that might be used as a drinking water source. The average annual carcinogenic risks for Cr in drinking water were determined to be in the range of 3.14E−05 and 7.90E−05 for adults and children, respectively. Similarly, the average annual carcinogenic risks for As in drinking water for adults and children were calculated to be in the range of 4.43E−07 and 1.11E−06, respectively. These values are within the risk values of 10−6 to 10−4, which generally indicate that there are health concerns that need to be addressed in more detail. The highest values of carcinogenic risk for drinking water were mainly located in the northern part of the study area where there are industrial activities that are potential sources of arsenic and chromium in surface water and groundwater.