Spatial, temporal, and speciation variations of heavy metals in sediments of Nan'ao Island, a representative mariculture base in Guangdong coast, China.
Heavy metals in sediments from Baisha Bay, Nan'ao Island, one of Guangdong Province's largest mariculture bases in Southern China, were investigated. The results display that the concentrations of 6 heavy metals from surface sediments were 0.040-0.220 (Cd), 24.22-39.61 (Pb), 25.30-42.66 (Cr), 10.83-19.54 (Ni), 15.06-39.24 (Cu) and 55.12-141.73 mg kg(-1) (Zn), respectively. The highest concentrations and the greatest increasing rates of heavy metals were found in a sediment core in a fish cage culture area due to receiving sewage discharge, uneaten fish bait, and boat gasoline combustion. Cd was preferentially associated with the acid-soluble fraction and Pb mainly with the reducible fraction in surface sediments. Meanwhile, Cd and Pb displayed greatest labile fractions, indicating anthropogenic origin. A principal component analysis (PCA) revealed three groupings (Cd; Cr, Ni and Cu; Pb and Zn) that mainly result from different distributions of the metals in the various fractions. The ecological risk of the polluted sediments stemmed mainly from Cd, and from Pb and Cu to a lesser degree. It is suggested that the density of fish-stocking be controlled, periodic movement of rafts (cages) be introduced, and the total numbers of net-cages and human activities in the mariculture zones be restricted. in order to facilitate the recovery of the polluted sediment.
Institute of Hydrobiology, Jinan University, Guangzhou 510632, China.
Yangguang
Y
Gu
Yufeng
Y
Yang
Qin
Q
Lin
Qusheng
Q
Li
Zenghuan
Z
Wang
Xunuo
X
Wang
D017756:Aquaculture; D002681:China; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D019216:Metals, Heavy / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data
D019216:Metals, Heavy; D014874:Water Pollutants, Chemical