Heavy metal toxicity in Exosphaeroma gigas (Crustacea, Isopoda) from the coastal zone of Beagle Channel

GIARRATANO; COMOGLIO; AMIN

ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY

Elsevier

Año: 2006

0147-6513

Acute toxicity of copper, cadmium and zinc on isopod Exosphaeroma gigas was evaluated at 20¡ë and 30¡ë salinity. Six concentrations were assayed to estimate EC50 values, while physiological responses and bioaccumulation were determined at 0.42 and 1.95 mg*L-1 of each metal. The following toxicity orders were obtained: Cd ¡Ý Cu > Zn at 20¡ë salinity and Cu > Zn ¡Ý Cd at 30¡ë salinity.   Copper treatments showed a reduction on oxygen consumption at 30¡ë salinity, while an opposite trend was observed at 20¡ë salinity. Zinc caused dissimilar effects, while in cadmium significant reduction was only registered in 0.4220¡ë mg*L-1. Ammonia excretion was generally higher in treatments than control at 20¡ë salinity. At 30¡ë salinity, excretion did not change in relation to control or diminished. In general terms, O:N atomic ratios indicated a preponderant protein metabolism. Bioaccumulation of assayed metals was higher at lowest salinity and increased with increasing toxic concentrations.