Dongyu River is the main tributary with the largest watershed area flowing into Nansi Lake.In order to understand the water quality and health risk level of Dongyu River,surface water samples were collected from the upper river to the river outlet.Concentrations of dissolved organic carbon (DOC),nitrogen,phosphorus,mercury (Hg),arsenic (As) dissolved oxygen (DO) and salinity were analyzed.Health risk of the pollutants via drinking the water in Dongyu River was evaluated by using the models of US EPA.The results show that the average concentrations of DO,As,ammonium (NH3),total phosphorus (TP) and Hg are 9.39 mg/L,0.002 6 mg/L,0.61 mg/L,0.27 mg/L and 0.000 25 mg/L respectively.DO and As concentrations at each sampling site meet the requirements of type Ⅲ standard in the GB3838-2002 National Environmental Quality Standards for Surface Water,while Hg,TP and NH3 concentrations exceed the standard values in 90.9 ％％,45.5 ％,and 18.2 ％ of the sampling sites respectively.Moreover,the average concentration of Hg was 2.5 times of the standard value.Each parameter has a significant spatial change along the river;generally high concentrations of nitrogen,phosphorus and organic matters are found in the middle and lower reaches of Dongyu River.DOC is significantly correlated with nitrogen and phosphorus,while As is positively correlated with DOC but negatively correlated with nitrite (NO-2).The carcinogenic health risk values of As is in the range of 0.31 × 10-5-5.04 × 10-5/a,which accounts for more than 99.95％ of the total health risk.The total hcalth risk of As,NH3,Hg,NO-3 is within the range of the up-limit tolerant level of 10-6-10-4/a recommended by US EPA and other organizations.
water qualityhealth risk assessmentDongyu RiverNansi Lake
NETL
NSTL
维普
万方数据
