Toxicity of chlorpyrifos, endosulfan and lambdacyalothrin and the binary mixtures on ?pejerrey? (Odontesthes bonariensis) larvae

GONZALEZ, P.V.; LÓPEZ ACA, V.; CARRIQUIRIBORDE, P.

Buenos Aires

Congreso; Society of Environmental Toxicology and Chemistry, Latin-American XI Biennial Meeting; 2015

Society of Environmental Toxicology and Chemistry, Latin-American

Chlorpyrifos (CL), endosulfan (ED) and lambdacyalothrin (LC), are among the most used pesticides in Argentina. It was found they are able to reach freshwater ecosystems. Little is known about the toxicity of these compounds and their mixtures on local fish species. The ?pejerrey? (O. bonariensis) is a valued gamefish species characteristic of the meridional sector of the ?del Plata Basin?, a core agriculture area of South America. The aim of the present study was to assess the acute lethal effects of these pesticides and their mixtures on pejerrey larvae. Four independent semi-static standardized toxicity test were conducted with the compounds alone or in their binary mixtures at the following toxic unit (TU) proportions: 1:3, 1:1 and 3:1. The 48 and 96h-LC50 for each active ingredient was estimated by the Probit method and TU as the ratio 1/LC50. A Concentration Addition model (CA) was assumed and the departure from the model was tested by the Chi-square test. Toxicity rank of tested active ingredients based on the 96h-LC50 was: LC 0.02 µg/L (0-0.05), EN 0.6 µg/L (0.19-1.86), and CL 1.71 µg/L (0.16-4.64). Mixtures significantly (P