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The concentrations, sources, and risks of heavy metals (Fe, Al, Mn, Cr, Co, Ni, Cu, Zn, As, Cd, W, Pb, and Tl) in sediments in five river-lake ecosystems in the Poyang Lake region were studied. The concentrations of the heavy metals varied spatially, with most of the highest concentrations in the Raohe river-lake ecosystem (RH). All heavy metals except As, Cd, W, and Tl were enriched in sediments possessing high total organic carbon contents or in finer sediments. Based on enrichment factors and statistical methods, it was found that Cd in sediments in the Xiushui (XS), Ganjiang (GJ), Xinjiang (XJ) river-lake ecosystems, and RH; Mn in the XS, GJ, and RH; and W in the XS and GJ were greatly affected by anthropogenic inputs. Moreover, the origins of Cu, Zn, and As require more attention due to the high concentrations found. The high enrichment factor of Cd in the sediments indicated that this metal might cause significant pollution in the environment. The results of the modified potential ecological risk index revealed that the XS, GJ, RH, and XJ were at considerable ecological risk, while the sediments in the Fuhe river-lake ecosystem (FH) were at moderate ecological risk, with Cd contributing the highest proportion of risk. The hazard score fundamentally validated the modified potential ecological risk analysis and revealed a mean toxicity of 57.80% to the benthic organisms in the RH. [ABSTRACT FROM AUTHOR]

Investigating the mechanisms that influence the concentration of heavy metals (Cu, Cr, Ni, Zn, Pb, and Cd) and possible sources of these elements is vital in developing lake management strategies and conserving lake ecosystems. This is the first systematic research focusing on the content, distribution, and origin of heavy metals in Poyang Lake area, the largest freshwater lake in China. Samples were collected, and the concentration of trace elements was measured. The distribution, sources, and potential ecological risk, which has undergone rapid economic development and intensive anthropogenic activity, was evaluated. Multivariate statistical analyses were carried out to determine the relationship between these trace elements and to identify the possible pollution sources. Assessment methods were carried out by applying the geoaccumulation index ( I) along with potential ecological risk indices (PERI) and USEPA guidelines. The results show that: (1) in comparison to Chinese Soil Standard I, the study area was polluted with Cd and Cr, which had an average concentration that was higher than the Class I criteria. However, the results showed that the heavy metal concentration of Cd was lower than that in other areas. (2) The correlation analysis indicates that Pb and Cd may potentially have the same pollution source. (3) The geoaccumulation (Igeo) and potential ecological risk index (PERI) of these metals were evaluated. The average pollution degree of Igeo decreased in the following order: Cd > Cr > Ni > Cu > Zn > Pb > As, which is similar to that observed from the EF values. PERI varied between 48.64 and 453.45 for all metals, and the general average was calculated as 113.71. Both Igeo and ER indicate that the study area was polluted by Cd. The results of FA show that 87.90 % of the variance could be explained by three factors and an independent variable. The research results obtained from this study can provide the scientific impetus to create policies for the economic development and environmental protection in Poyang Lake and other areas of the world. [ABSTRACT FROM AUTHOR]