전자저널 > 전자저널 > Uptake and Loss Kinetics of Silver in the Asian Clam, Potamocorbula amurensis and Balthic Clam, Macoma balthica: Effects of Body Size and Salinity

Uptake and Loss Kinetics of Silver in the Asian Clam, Potamocorbula amurensis and Balthic Clam, Macoma balthica: Effects of Body Size and Salinity

Tae Seob Choi, Jung-Suk Lee, Byeong-Gweon Lee and Kwang Young Kim

Institute of Environmental Protection and Safety, NeoEnBiz Co., Digital Valley 2-904, 481-10, Gasan-dong, Geumcheon-gu, Seoul 153-783, Korea

A series of radiotracer experiments were employed to quantitatively compare the biokinetics of uptake from the dissolved phase (influx rates), uptake from the various types of food source (assimilation efficiency), and loss (efflux) of Ag between Potamocorbula amurensis and Macoma balthica. Simultaneously, influx rates of dissolved Cd in both clams were determined to compare with those of Ag. Effects of salinity on influx rates were evaluated in these 2 euryhaline species, as were effects of clam size. Influx rate of Ag and Cd (μg g-1 [dry wt.] d-1) increased linearly with metal concentrations. Influx rates of Ag in both clams were 3 to 4 times those of Cd. Absolute influx rates of the 2 metals were 4 to 5 times greater in P. amurensis than M. balthica, probably because of differences in biological attributes (i.e. clearance rate or gill surface area). As salinity was reduced from 20 to 2.5 psu, the influx rate of Cd in P. amurensis increased 4-fold and that of Ag increased 6-fold, consistent with expected changes in speciation. Weight-specific metal influx rates (μg g-1 [dry wt.] d-1) were negatively correlated with the tissue dry weight ofthe clams, but most rate constants determining physiological turnover of assimilated metals were not affected by clam size.

v211p07.pdf (1.2M), Down : 97, 2008-03-11 18:47:19