Assessment of Heavy Metals Pollution in Sediments from Aha Lake, China

Assessment of the pollution for the selected six heavy metals (Pb, Cu, Zn, Fe, Mn and Ni) in ten surface sediments sampled from Aha Lake in a dry season was made in the present investigation. Principal component analysis (PCA) was used to assess the sources of the heavy metals contamination and two components were extracted. Analysis of the lake characteristics and point source pollution revealed that the discharge of industrial effluent and coal mining wastewater were the possible sources of these heavy metals contamination. Based on the speciation characteristics of heavy metals in sediments, the method ratio of secondary phase to primary phase (RSP) was applied to evaluate the loadings and the bioavailability of these heavy metals. The RSP evaluation exhibited that Pb, Zn, Fe, Mn and Ni were mainly associated with Fe-Mn oxides besides residual phase, while Cu mainly existed in organic phase and residual phase. In summary, the potential risk posed to the lake caused by the heavy metals was high and descended in the order of Mn > Ni > Zn > Pb > Cu > Fe.

Ecological Risk Assessment of Heavy Metals in Sediments from Aha Lake, China

In the present work, contamination and potential ecological risk of six heavy metals (Pb, Cd, Hg, As, Cu and Zn) in sediments of Aha Lake, one of the five drinking water sources for Guiyang City, were assessed based on a method which is associated with toxic-response factors of contaminants. For comparison, the two sets of reference data representing the pre-industrial and the local baseline pollution levels were employed. When the pre-industrial levels were taken as references, the accumulating coefficients on average diminished in the order of Zn > As > Hg > Cd > Cu > Pb, and the potential ecological risk descended in the order of Hg > Cd > As > Cu > Zn > Pb. When the local baseline values worked as references, the accumulating coefficients on average diminished in the order of Cd > Zn > Hg > Cu > As > Pb, and the potential ecological risk descended in the order of Cd > Hg > As > Cu > Zn > Pb. It is evident that Cd and Hg are the critical elements in terms of potential ecological hazard in Aha Lake among these six heavy metals.