PESTICIDES TOXICITIES: SENSITIVITY VARIATION OF THE FRESHWATER PRAWN AND CRAB

MONTAGNA M.; COLLINS P.

Coquimbo Chile

Congreso; The Crustacean Society, Summer meeting, Coquimbo, Chile, 2007; 2007

The Crustacean Society

Pampas region of Argentina is characterized by intensive agriculture and urbanization, and diverse pesticides are usually used for control of a broad spectrum of pests. Their application  affect a great variety of not-target species from freshwater habitat. Palaemonetes argentinus prawn and Trichodactylus borellianus crab are the most common species and with wide distribution (Paraguay, Uruguay, southern Brazil, and the north and centre of Argentina (Pampas region)). These species and environments are susceptible to receive the influence of biocids, such as herbicides, insecticides and fungicides, when they input in lotic and lentic environments. Differences in toxicities, in terms of acute lethal toxicity (LC50-96h), of agrotoxics in their commercial formulations (glyphosate, 2,4D, chlorpyrifos, endosulfan, cypermethrin and carbendazim) were evaluated in these crustaceans. In glyphosate exposure the LC50 values were similar between prawn and crab, and its toxicities were lower than those obtained for 2,4D, being moreover more toxic in crabs. In both species, the pyrethroid cypermethrin showed more toxicity than organophosphate chlorpyrifos and organochlorine endosulfan. The LC50 values for these insecticides were significantly smaller in the prawn than in the crab. Mortality in exposed crabs to carbendazim was not registered when these were in intermolt phase. However the carbendazim LC50 in prawns was 0.065 gL-1. Results indicate that the sensitivities of used decapods were different, being the sensitivity of the prawn greater than the crab. This suggest that the morphology of body, branchial chamber characteristics and behaviour of the species are important to the survival in adverse environment conditions.