Metal accumulation, growth and reproduction of razor clam Sinonovacula constricta transplanted in a multi-metal contaminated estuary

Publication date: 15 September 2018
Source:Science of The Total Environment, Volume 636
Author(s): Yizhou Ke, Wen-Xiong Wang
In recent years, elevated metal discharges have seriously affected the health of many estuarine ecosystems in China. This study examined the influences of metal pollution on the growth and reproduction of razor clam, Sinonovacula constricta. An eight-month field experiment was conducted at two sites with different contamination levels in Jiulong River Estuary of Southern China. Concentrations of Ag, As, Cd, Cr, Cu, Ni, Pb and Zn in seawater, suspended particles, surface sediments, and clams, as well as the clam growth and gonad condition were simultaneously determined on a monthly basis. Over the 8-month period, Ag, Cu and Ni concentrations in the clams were significantly higher at the more polluted site, whereas the concentrations of other metals were rather comparable between the two sites. Comparison of the 8-month pattern of metal concentrations among different compartments suggested that Ag, As, Cd, Cu and Zn bioaccumulation in the clams was mainly derived from ingestion of suspended particles, whereas Cr and Ni accumulation was mainly from the waterborne uptake. The growth of clams in the more polluted site was depressed and there was no significant growth after 4 months of transplantation, which was mainly caused by Cu and Ag accumulation in the clam tissues. Correspondingly, the gonad somatic index was also lower at the more polluted site. Our study demonstrated a significant impact of multi-metal pollution on the growth and reproduction of clams in an estuary. Simultaneous measurements of metal bioaccumulation were important for the interpretation of metal toxicity observed in the field.

Graphical abstract

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