Distribution characteristics and risk assessment of nutrient and heavy metal pollution in sediment in Taihu Lake
Sediments samples collected from 53 sites in various regions of Lake Taihu were analyzed for total nitrogen,total phosphorus,organic matter,and eight heavy metals(Hg,As,Cu,Zn,Pb,Cd,Ni,Cr)in both surface and vertical sediments layers.The spatial distribution characteristics of sediment nitrogen,phosphorus and heavy metals in different regions were mapped using a ArcGIS information system,and then evaluated the ecological risks of various pollution indicators.In the surface sediment(0～10cm)of Lake Taihu,the total nitrogen content ranged from 561 to 2707 mg/kg with an average value of 1502 mg/kg,which is moderately polluted,the total phosphorus content ranged from 308 to 1156 mg/kg with an average value of 532mg/kg,which is moderately polluted,the organic matter content ranged from 1.69%to 3.44%with an average value of 2.35%.Spatially,pollution degree gradually increased from the central region of Lake Taihu towards the northwest,especially in the three places of Zhushanhu,East Taihu and Westcoast.In terms of heavy metals,the pollution levels gradually increased from the southeast to the northwest,with particularly severe pollution observed in the Zhushanhu,Westcoast,and Southern coastal area.Among the eight heavy metal pollutants,Cd contamination is the most severe.In the vertical distribution characteristics,nitrogen,phosphorus and heavy metals tend to accumulate in the surface sediment,and then decreased layer by layer on the vertical distribution of 0～30cm.
万方数据
维普
