Pollution characteristics and health risk assessment of heavy metals in gully pond water and its surrounding shallow groundwater

Taking 4 gully ponds water and its surrounding shallow groundwater in a village in Henan Province as the research object, the samples were collected during the wet season, the concentrations of 13 heavy metal elements Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Ag, Cd, Hg and Pb in the water were determined, and the impact of gully pond water and its surrounding shallow groundwater quality and potential health risks were evaluated. The results showed that the heavy metals in the gully pond water were heavily polluted, among which the concentrations of Mn and Fe exceeded Class Ⅳ limits of Environmental Quality Standards for Surface Water (GB 3838-2002), and the average exceeding multiples were 5.5 times and 9.0 times, respectively. The heavy metals in the surrounding shallow groundwater were generally slightly polluted. Among them, the concentration of Al, Mn, Fe and Ni exceeded the Class Ⅲ limits of Standard for Groundwater Quality (GB/T 14848-2017). The concentration of heavy metals in the shallow groundwater decreased with the increase of the distance from the pond. The concentrations of 6 heavy metal elements of Al, Cr, Ni, Pb, Mn and Fe had a negative logarithmic relationship with the distance from the pond. The sum of non-carcinogenic risk of children and adults ingesting 13 heavy metal elements in shallow groundwater through drinking water was 0.296 and 0.309, respectively, which were both less than 1 or in the acceptable level. And the carcinogenic risk of lifetime exposure of children and adults to 5 heavy metal elements(Cr、Ni、As、Cd、Pb)was 1.44×10^-5 and 7.52×10^-5, respectively, which exceeded 1.0×10^-6 (a higher health risk of cancer). The gully pond water in the study area had a certain impact on its surrounding shallow groundwater, and the carcinogenic health risks of children and adults exposed to heavy metals in shallow groundwater through drinking water deserved special attention.