Glyphosate is a widely used broad-spectrum weed control agent. In the present study, an in vivo study on the genotoxic effects of a technical herbicide (Roundup) containing isopropylamine salt of glyphosate was carried out on freshwater goldfish Carassius auratus. The fish were exposed to three doses of glyphosate formulation (5, 10 and 15 ppm). Cyclophosphamide at a single dose of 5 mg/l was used as positive control. Analysis of micronuclei, nuclear abnormalities and DNA damage were performed on peripheral erythrocytes sampled at intervals of 48, 96 and 144 h posttreatment. Our results revealed significant dose-dependent increases in the frequencies of micronuclei, nuclear abnormalities as well as DNA strand breaks. Our findings also confirmed that the alkaline comet assay and nuclear deformations in addition to micronucleus test on fish erythrocytes in vivo are useful tools in determining the potential genotoxicity of commercial herbicides.

In this study, the genotoxic effects of a widely used herbicide, trifluralin, and its commercial formulation, Treflan, were evaluated using the micronucleus test in a commercially important fish species, Oreochromis niloticus (Nile Tilapia). Fish were exposed to 1, 5, and 10 microg/L doses of trifluralin and Treflan for 3, 6, and 9 days under laboratory conditions. Ethylmethanesulfonate, at a single dose of 10 mg/L, was used as positive control. Micronuclei were evaluated on the peripheral erythrocytes. Both Treflan and trifluralin treatments significantly increased the micronucleus frequencies in peripheral erythrocytes of O. niloticus. Furthermore, the genotoxicity of the active ingredient, trifluralin, was observed to be higher than that of the commercial formulation Treflan. Our results indicate that herbicide trifluralin has genotoxic potential in fish.

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Okadaic acid (OA) involved in Diarrheic Shellfish Poisoning (DSP) is a marine toxin produced by dinoflagellates such as Prorocentrum sp. Although the neurotoxic properties of DA are well documented, very little is known regarding in vivo genotoxicity of OA on aquatic organisms, especially on fish. In the present paper, an in vivo study on the genotoxic effects of OA was carried out on a model fish Oreochromis niloticus using the micronucleus test and the comet assay. The fish were exposed to three different doses of okadaic acid via intraperitoneal injection. Ethyl methane sulphonate (EMS) at a single dose of 5 mg/l was used as positive control. Analysis of micronuclei, nuclear abnormalities and DNA damage were carried out on peripheral erythrocytes sampled at intervals of 24, 48 and 72 h post treatment. Our results revealed significant increases in the frequencies of micronuclei, nuclear abnormalities as well as DNA strand breaks indicating the genotoxic potential of OA on fish.