CHRONIC GENOTOXIC EFFECTS AND RECOVERY CAPABILITIES ON HYPSIBOAS PULCHELLUS TADPOLES (ANURA, HYLIDAE) AFTER IMAZETHAPYR HERBICIDE EXPOSURE

PEREZ IGLESIAS, JM; SOLONESKI S.; NATALE G.S.; LARRAMENDY M.L.

Buenos Aires

Jornada; XVIII Jornadas Anuales Multidisciplinarias; 2016

Sociedad Argentina de Biologia

Imazethapyr (IMZT) is a widely herbicide used in soybean and corn for weed control. Actually, there are few studies evaluating sublethal effects of this herbicide in aquatic vertebrates. The aim was to evaluate sublethal effects by chronic exposure to environmentally relevant concentrations of IMZT (constant exposure) and their recovery capabilities to genotoxic effects after an exposure pulse in circulating erythrocytes of H. pulchellus tadpoles. Tadpoles were exposed to IMZT-based herbicide formulation Pivot H® in two bioassays. First, a chronic assay was carried out by flow-through employing 0.19 mg/L IMZT (12.5% LC50 value) during 28 days from GS25 until metamorphosis. Second, a recovery assay with two phases; an exposure phase at 0.39 mg/L IMZT (25% LC50 value) during 4 days and a post-exposure phase in dechlorinated tap water during 21 days from GS37 until metamorphosis. Dechlorinated tap water and cyclophosphamide was used as negative and positive control, respectively. For chronic assay tadpoles were sacrificed every 7 days. For recovery assay, tadpoles were sacrificed after exposure phase and each 7 days in post-exposure phase. The micronucleus test (MNs) and the comet assay were employed as endpoints. Data were analyzed by t-test and one-way ANOVA with a posterior Dunnett test. Results showed that H. pulchellus tadpoles present cytogenetic damage remaining until metamorphosis due to chronic exposure to IMZT evidenced by MNs (p < 0.05) as well as by the comet assay (p < 0.01) when comparing control with herbicide-exposure group. On the other hand, evaluating recovery capabilities on H. pulchellus tadpoles, our results showed that tadpoles return to basal levels of DNA damage after 7 days post exposition (p > 0.05). These studies aim to protect amphibian populations to DNA damage from contaminant exposure.