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Surface sediment samples were collected from 10 typical locations throughout the Dongting Lake, China, in January 2009. Samples were assayed by atom absorption spectrophotometer and cold atomic fluorescent spectrophotometer for Pb, Cd, As, Hg. In order to investigate the spatial distribution characteristics, sources, and potential ecological risks of heavy metals, the geostatistics method, potential ecological risk index, and multivariate statistical analysis were applied. The results showed that except for the content of Hg, the contents of Pb, Cd, and As had similar spatial distribution characteristics. The average contents of Cd and As exceeded the second class contents of the National Standard for Soil Environment Quality (GB15618-1995), especially that for Cd. The potential ecological risk posed by these heavy metals decreased in the order of the outlet of the Dongting Lake > the East Dongting Lake > the South Dongting Lake > the West Dongting Lake spatially. From the results of multivariate statistical analysis, Pb and Cd, as the first group, were considered to be rooted in mining smelting processes for developed mining and heavy industry. And Hg, as the second group, was mainly derived from parent material weathering, while As was probably considered to originate from both sources above. [ABSTRACT FROM PUBLISHER]

Abstract: Surface sediment (0–10cm) samples were collected from 12 typical sites throughout the Dongting Lake. Samples were detected by inductively coupled plasma–mass spectrometry and atomic fluorescence spectrometry for Cr, Cu, Zn, Pb, Cd, As, and Hg, respectively. Based on geostatistics analyses, generally distributions of these heavy metal contents except that of Hg decreased in the order of the South Dongting Lake>the East Dongting Lake>the outlet of Dongting Lake≈the West Dongting Lake. Sediment quality guidelines (SQGs) and Hakanson's method were used to determine potential risk of heavy metal contamination. The results indicated that the mean contents of As and Cd exceeded the probable effect level (PEL), and there were 58% for Cd and 50% for As out of all sampling sites exceeding PEL. The calculated mean potential ecological risk degrees were in the descending order of Cd, Hg, As, Pb, Cu, Cr and Zn. Besides, multivariate statistical analyses revealed that Zn, Pb, Cd and As mainly originated from mining wastewater and industrial wastewater which were probably in the close relationship with characteristics about the Yueyang city and the Xiangjiang River. Cr and Cu mainly derived from natural erosion and nonpoint agricultural sources. However, Hg originated from both sources. Cluster analysis indicated that Cluster 1, S5, S6 and S10 included, were probably taken as the higher polluted sites, and Cluster 2, S7, S9 and S11 included, might be explained as the moderate pollution regions. [Copyright &y& Elsevier]