Study on Pollution Sources and Degree of Sediments in Northwestern Rivers Flowing into Taihu Lake

[ Objective] The study aimed to analyze the pollution sources and degree of sediments in seven northwestern rivers flowing into Taihu Lake. [ Method] Based on a survey for the sediments in seven rivers flowing into the northwestern Taihu Lake from 2005 to 2007, the molar ratio of major elements was used to determine the main pollution sources of each channel, and the heavy metal pollution of sediments in the seven rivers was assessed by enrichment coefficient. [ Result] Mashan River, Liangxi River and Xiwan River mainly suffered municipal pollution; Zhihu Port and Caoqiao River were chiefly subjected to industrial pollution; Dapu River and Wujin River were mainly affected by agricultural pollution. In addition, the rivers mainly suffering industrial pollution had the most serious heavy metal pollution, followed by the rivers mainly undergoing agricultural pollu- tion, while the rivers chiefly affected by municipal pollution had the minimum pollution. [ Conclusion] The research could provide scientific references for the control of river pollution by heavy metals along Taihu Lake basin.

Relationship between heavy metal concentrations of herbaceous plants and soils at four Pb-Zn mining sites in Yunnan,China

This paper studied the relationship between heavy metal concentrations of herbaceous plants and soils at four Pb-Zn mining sites in Yunnan,China.50 herbaceous plant samples of 9 plant species from 4 families and 50 soil samples were collected and then ana1yzed for the tota1 concentrations of Pb,Cd,and Zn.The results showed that the average concentrations of Pb,Cd,and Zn in soil samples were 3772.83,168.81,and 5385.65 mg/kg,respectively.The average concentrations of Pb,Cd,and Zn were 395.68,28.14,and 1664.20 mg/kg in the shoots,and 924.12,57.25,and 1778.75 mg/kg in the roots,respectively.Heterospecific plants at the same site and conspecific plants at various sites had different average levels of Pb,Cd,and Zn,both in the shoots and the roots.Enrichment coefficients of Pb,Cd,and Zn were greater than 1 in 2,3,and 9 herbaceous plant samples,respectively.Translocation factors of Pb,Cd,and Zn were greater than 1 in 10,17,and 25 herbaceous plant samples,respectively.In all 50 samples,the concentrations of Pb,Cd,and Zn between the shoots and the roots,the shoots,and the soils,and the roots and the soils had significant positive relationships.