Embryo-larvae and juvenile toxicity of Pb and Cd in Northern Chilean scallop Argopecten purpuratus.

Abstract

This study aimed to investigate the effects of Cd and Pb on earlier stage of the commercially important scallop (Argopecten purpuratus) in the contamination context of Northern Chile where this specie is farmed, through acute exposure bioassays in embryo-larvae measuring cumulative abnormality (EC50) and juvenile cumulative mortality (LC50) as endpoints, based on environmentally detected concentrations and available toxicological data from similar species. Embryo-larvae exposure indicates 48h EC50 of 1.55mg/L Cd, and 0.044mg/L Pb. On the contrary, 96h LC50 in juvenile scallops was 0.48mg/L Cd and 1.47mg/L Pb. Our results demonstrated differential toxicity between embryo and juvenile scallops that might relate to different primary defense mechanisms or effect in morphological development of individuals in each ontogenetic stage. Compared to similar bivalve metal toxicity tests, this study demonstrated that A. purpuratus embryos are more sensitive to Pb than most other bivalve species. Our results indicate that maximum permitted levels of Pb in marine waters and estuaries (according to Chilean regulation) could pose a risk for scallops' first stage of life (embryo-larvae) development, and needs to be reviewed. Furthermore, Chilean environmental regulations do not have quality standards for marine sediments (currently under discussion), where high levels of metals have been continuously reported.