Cadmium and Zinc in Mar Chiquita Coastal Lagoon (Argentina):Salinity Effects on Lethal Toxicity in Juveniles of the Burrowing Chasmagnatus granulatus

ORNELA BELTRAME,; SILVIA DE MARCO; JORGE MARCOVECCHIO

Archives of Environmental Contamination and Toxicology

Elsevier

Año: 2008 vol. 55 p. 78 - 85

0090-4341

The large Argentine marine littoral zone is characterized by great number of wetlands and includes only one coastal lagoon, Mar Chiquita, which has been declared as Biosphere Reserve by Man and Biosphere Reserve Program from UNESCO. Its margins present populations of Chasmagnathus granulatus, a  semiterrestrial crab distributed along wide salinity gradients which plays an important role as a key species within the corresponding trophic web. Dissolved cadmium (Cd) and zinc (Zn) concentrations present in this ecosystem were determined. Cadmium concentrations ranged between 0 and 0.82 ìg.L-1 and Zinc levels ranged from 0 and 1224.38 ìg.L-1 within the mentioned coastal lagoon. Cadmium and Zinc acute semistatic toxicity bioassays were carried out for 96 h on juvenil crabs of Chasmagnathus granulatus. LC50-96 h values were 2.24 mg Cd2+.L-1 and 7.07 mg Zn+2.L-1 at 5 psu, and 15.42 mg Cd2+.L-1 and 11.41 mg Zn+2.L-1 at 25 psu. Both metals showed to be more toxic at lower salinities. C. granulatus juveniles LC50-96 h values determined for cadmium were two orders of magnitude higher than the corresponding metal concentrations in Mar Chiquita coastal lagoon, nevertheless those zinc values determined were similar to several ones corresponding to natural water samples.