Oxidative injury caused by individual and combined exposure of neonicotinoid, organophosphate and herbicide in zebrafish

- Mixture toxicity emerged as greatest challenges in environmental toxicology.
- Combined (CMD) group shows maximum alterations (even at half dose).
- Individual exposure shows selected target organ toxicity.
- Combined exposure develops toxic manifestations in all three examined tissues.

The greatest challenge in environmental toxicology is to understand the effects of mixture toxicity as environmental pollutants co-exist and exhibit combined effects. Thus, it is necessary to evaluate the mixture toxicity associated with two or more co-existing compounds. Pesticides are widely used to control pest, they are ubiquitous in nature and present in all environmental components. Pesticide residue can be detected in almost all components of environment and food samples. Imidacloprid (IMD) (neonicotinoid), dichlorvos (DIC) (organophosphate) and atrazine (ATZ) are three widely used pesticides for commercial uses. Present work includes the assessment of effects of individual exposure of IMD (27.5 mg/L), DIC (15 mg/L), and ATZ (03 mg/L) and in combination of three (CMD) (13.75 + 7.5 + 1.5 mg/L IMD, DIC & ATZ, respectively) in terms of LPO, GSH content and antioxidant enzymes activities (superoxide dismutase, catalase and glutathione peroxidase) in zebrafish (Danio rerio), exposed for 24 h. CMD group exhibits highest lipid peroxidation than other individually exposed groups. Similarly, the activities of antioxidant enzymes were highest in CMD group with reduced GSH content. Results indicate that exposure to mixture of pesticides develops synergistic effects which were more toxic in compare to individual exposure and also produce toxicity in all examined tissues rather than selective organ toxicity.

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