Ecotoxicological study about the effects of Endosulfan in the viviparous fish Jenynsia multidentata (Anablepidae, Cyprinodontiformes).

BALLESTEROS, M.L; MIGLIORANZA, K.S.B.; WUNDERLIN, D.A; BISTONI, M.A

Berlin

Congreso; 6th SETAC World Congress / SETAC Europe 22nd Annual Meeting; 2012

Ecosystem services such as purification of air and water are being impaired by many human activities such as unsustainable agricultural practices. The use of pesticides leads to the pollution of many aquatic habitats worldwide. Viviparous fish Jenynsia multidentata (Anablepidae, Cyprinodontiformes) is proposed as a bioindicator because its wide distribution along the Neotropical region of South America and inhabits polluted an unpolluted sites. The aim of this work was to develop an integral analysis of pesticide effects at different levels of organization in J. multidentata under Endosulfan (EDS) exposure. First, the acute toxicity (LC50) of technical-grade EDS was determined and histomorphological alterations in gills and liver was described and quantified. Second, sublethal toxicity tests (0.014?1.4 μg.L-) were carried out. As biomarkers of effect, response of detoxification and antioxidant systems (GST, GPx, GR, and CAT) and the effects on Lipid Peroxidation (LPO) were measured in different organs. Neurotoxic effects of EDS were evaluated through the AchE activity in brain and muscle. At behavioral level, swimming activity was recorded. As biomarkers of exposition, accumulation of technical-grade of EDS and Endosulfan sulfate (ES) was measured. The LC50-96 was lower in males (0.72 μg L-1) than females (1.32 μg L-1). The histomorphological alterations in gills such as epithelial lifting are considered as defense responses to minimize the entry of EDS into the blood stream. In liver, the histological alterations varied between reversible changes at lower concentrations to irreversible changes at the highest concentration. At biochemical level, liver and brain were the most damaged organs and presented the highest levels of LP. At behavioral level, hypoactivity was observed in relation to the exposure time. These swimming activity changes were associated with the inhibition of AchE activity in muscle modifying the normal behavior of fish. The accumulation of the metabolite ES in all tissues indicate biological transformation of EDS. Moreover, measurement of technical grade EDS as well as ES is suitable biomarkers of exposure under field conditions under field conditions. If the stressful conditions persist, the mentioned alterations would lead to changes at population levels.