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Depuration of metals by the green‐colored oyster Crassostrea sikamea
Author(s) -
Wang Lei,
Wang WenXiong
Publication year - 2014
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.2695
Subject(s) - oyster , environmental chemistry , crassostrea , chemistry , metal , estuary , effluent , fishery , environmental engineering , environmental science , biology , organic chemistry
The accumulation of metals (especially copper) in oysters has led to green‐color now being found in Chinese estuaries. In the present study, the authors quantified the depuration of 8 metals (Ag, Cd, Co, Cr, Cu, Ni, Pb, and Zn) in green‐colored oysters ( Crassostrea sikamea ) collected from an estuary that is heavily contaminated by metals as a result of industrial effluent releases. The oysters were depurated under laboratory conditions for 4 mo; the accumulated concentrations and the subcellular distribution of metals were measured at different time intervals. Results showed that the green color of oysters faded to light yellow (nearly normal) after 4 mo of depuration. Depuration of metals could be described by a first‐order kinetic process. The calculated overall depuration rate constants of metals were in the range of 0.008 d −1 to 0.024 d −1 , with a biological retention half‐life of 30 d to 70 d. The depuration rates of green‐colored contaminated oysters were significantly higher for Cd, Cu, Cr, and Ni than the rates of oysters from a less contaminated site, whereas the depuration rates of Ag, Co, Pb, and Zn were comparable between the 2 populations. When corrected for the change of oyster tissue weight, the actual efflux rate constants of the metals (0.0708–0.1014 d −1 ) were much higher than the overall depuration rate constants. Cellular debris and metallothionein‐like proteins were the important fractions binding with the metals in the oysters. Significant changes in metal subcellular distribution were observed during the 4‐mo depuration for Ag, Cd, Cu, and Zn. Metallothionein‐like protein became more important in sequestering the metals during the depuration period, with a concomitant decrease in metals associated with the cellular debris fraction. Environ Toxicol Chem 2014;33:2379–2385 . © 2014 SETAC