Abstract:

As a repository or a source of various contaminants under different conditions, contaminated sediments may pose immediate or potential risk to aquatic organisms. Proper sediments quality criteria (SQC), therefore, are required to indicate the contamination situation. Equilibriumpartitioning approach (EqP) has been intensively studied and incorporated into sediment assessment models in the last few years, and it is believed to be the most promising method to deriving sediment quality criteria. Using EqP approach, this research proposed relative SQC for metals (Cu, Zn, Cd, Pb, Ni, Fe, Hg and As) of the Yangtze River water system. The results of this relative SQC indicated that, in general, SQC declined along the Yangtze River, and it had an obvious area distinction, and most of the heavy metals studied such as Cu, Zn, Cd, Pb, Ni, Hg, As, Fe can be divided into several environment units because of the different environmental geochemistry conditions. The SQC obtained in the present study was comparable with those SQC values already obtained in other areas of China, but was higher than those in USA. As this SQC is only a numeric criterion without the consideration of any biological effects, further research, especially research on toxicity is needed before being used as an integrated assessment of sediments. Furthermore, this research showed the direction of further research and provided a possible way to establish SQC for metals.

Key words: the Yangtze River, metals, equilibriumpartitioning approach, sediments quality criteria