Investigation of the genotoxicity of endosulfan to freshwater Cyprinid fish Crucian carp (Carassius carassius L.) using the micronucleus and chromosomal aberration as biomarkers

Abstract

This study was aimed to evaluate the in vivo genotoxic effects of endosulfan in freshwater fish crucian carp, Carassius carassius L. The LC50–96h value of endosulfan (with 95 % confidence limits), determined by probit analysis, was 0.070 (0.046–0.093) ppm L−1 and the estimated safe levels of endosulfan varied from 00.70 × 10−2 to 00.70 × 10−6 ppm L−1. Based on the LC50–96h value, three test concentrations (viz. sub-lethal I, II, and III) were determined to be 0.052, 0.035 and 0.017 ppm L−1, respectively, and the fish specimens were exposed to these concentrations for 35 days. The mean concentration of endosulfan in water samples (aquaria) was always within 5 % of the intended concentration when analyzed by dispersive liquid-liquid micro extraction (DLLME) followed by gas chromatography–mass spectrometry (GC-MS). Autopsy was done on days 1, 2, 3, 4, 7, 14, 21, 28 and 35 of endosulfan exposure for assessment of micronucleus (MN) formation and chromosomal aberrations (CA). The MN formation in the peripheral erythrocytes, authenticated by scanning electron microscopy (SEM), was found to be significantly higher (p < 0.05) in all the treated groups, including positive control cyclophosphamide (4 ppm L−1) compared to negative control. Similar significant effects (p < 0.05) were also observed on CA in the head kidney cells. In general, both MN and CA exhibited a concentration and time-dependent response. The current study revealed the potential genotoxicity of endosulfan in fish; and that the micronucleus and chromosomal assays are useful tools in determining genotoxicity of water pollutants and might be appropriate as a part of environmental monitoring program.