T7 PM Metals and Bioaccumulation
Tuesday, 15 November 2005: 1:50 PM - 5:30 PM in 327-329

(AAA-1117-096848) Influences of Cd and Ag co-exposure on their uptake kinetics in green mussels.

Ng, T.¹, Wang, W.-X.¹, ¹ The Hong Kong University of Science & Technology, Hong Kong, China

ABSTRACT- Metal accumulation in co-exposure may be different from that in single exposure because metals compete for ligands during uptake or storage for detoxification. In this study, we determined how the co-exposure of Ag and Cd modified the corresponding metal uptake physiology and the subcellular distribution in the green mussels. The Cd assimilation efficiency was enhanced in the single Cd or Ag+Cd co-exposure after 4 weeks, but the enhancement was not influenced by Ag. There was an apparent interaction between Ag and Cd co-exposure on the dissolved uptake of both metals, but the interaction was dependent on the exposure period and the metal concentration. Ag exposure reduced the effects of Cd exposure on Cd dissolved uptake and vice versa for Cd exposure on the dissolved uptake of Ag. Metal interaction was more evident in the subcellular metal distribution. A much higher fraction of Ag was associated with the metallothionein-like protein (MTLP) in the Ag+Cd co-exposed mussels as compared to those only exposed to Ag, suggesting that Ag may displace Cd from MTLP that has a higher binding capacity with MTLP. Generally, our results imply an immediate interaction on the dissolved uptake of metals and a modification of subcellular metal distribution after metal co-exposure.

Key words: metals, co-exposure, bioavailability, mussels