Cadmium-copper antagonism in seaweeds inhabiting coastal areas affected by copper mine waste disposals

摘要

Cadmium and copper accumulation by macroalgae was studied in a coastal area exposed to upwelling events and high levels of Cu, the latter resulting from mine disposals. Eight species were studied, and all had very high concentrations of Cd outside of the Cu-contaminated area. Cu in algal tissues was much higher in contaminated than in reference sites. High Cu appeared to suppress Cd bioaccumulation; Cd in algal tissues was much lower in the Cu-contaminated area than in the reference sites. Transplant experiments with Lessonia nigrescens revealed a depuration of Cd in individuals transplanted to areas with high Cu. However, Cd depuration occurs more slowly than Cu uptake. These differences suggest that while Cd and Cu are linked mechanistically, it is not a simple substitution. Overall, the work confirms that macroalgae are useful indicators of metal contamination and may be used as in situ biomonitors for labile forms of metals, like free Cu2+. However, antagonistic relationships between metals must be clearly understood in order to properly interpret their concentrations in macroalgae.