Acute toxicities of four metals on the early life stages of the crab Chasmagnathus granulata from Bahia Blanca estuary, Argentina

Acute semistatic toxicity tests were carried out for 96 h with first zoeae and young crabs of Chasmagnathus granulata. Survival curves and LC50 (lethal concentration 50, the concentration which produces the death of 50% of the exposed population) indices for copper, zinc, cadmium, and lead were determined., Furthermore, mixture toxicity tests (Cd/Cu and Cd/Zn) with first-stage larvae were also carried out. The LC50-96 h values determined in this study were 1093.4 (881-1319) mu g Pb2+ L-1, 219.2 (188.9-248.9) mu g Cu2+ L-1, 172.1 (141.3-203.6) mu g Zn2+ L-1, and 47.8 (37.9-58.0) mu g Cd2+ L-1 for zoeae I and 130.1 (121.7-139.0) mg Cu2+ L-1, 51.0 (41.9-61.6) mg Zn2+ L-1, and 35.7 (30.1-41.9) mg Cd2+ L-1 for young crabs. The LC50-96 h indices for mixture tests with zoeae I were 260.6 (227.3-286.3) mu g Cd2+ /Zn2+ L-1 and 41.3 (37.4-60.7) mu g Cd2+ /Cu2+ L-1. Cadmium presented the highest acute toxicity for both stages of the life cycle examined. The toxicity of the metals analyzed followed the order cadmium > zinc > copper > lead. First zoeae were more sensitive than young crabs to acute exposure to all metals analyzed. The young crabs were considered potentially dangerous agents of transference to the associated trophic chain because of their relatively elevated resistance and their capacity to bioaccumulate heavy metals in their tissues. Mixed toxicity tests carried out on first-stage larvae showed different kinds of interactions. Cadmium/copper presented an additive interaction trend while the mixture cadmium/zinc showed an antagonistic interaction. (c) 2005 Elsevier Inc. All rights reserved.