Seasonal Distribution Characteristics and Health Risk Assessment of Heavy Metals in Surface Water of Qingjiang River

Abstract

In order to assess the health risks of heavy metals in surface water of Qingjiang River, surface water samples were taken at designed cross-sections of the river and analyzed for Cr, Cu, Zn, Pb, Cd, As, and Mn. Health risks from these heavy metals for adults and children in wet and dry seasons were compared by water environmental health risk assessment model of the USEPA. It found that the main excessive element is Mn, concentrating in the Danshui, Yantouxi, and Pingluoxi, the slightly excessive element is As, the concentration of Mn was above national standard, and it mainly distributed in Danshui, Yantouxi, and Pingluoxi, As was slightiy over the standard, and it concentrated in Wujiahe, The content of heavy metals during wet season were all higher than those during dry season. Cr, Cu, Zn, and Cd are mainly originated from the nature, Pb and As are separately mainly originated from traffic and agriculture, Mn originated from mining mainly in the downstream, while it has natural source from upper to middle. The health risks of heavy metals in surface water to adults and children in wet season are higher than those in dry season. The main health risk area was the midstream. As was the highest health risk element and children were the most preventive group. Specially, people in towns who drink the water from midstream should pay more attention.