UTTAR PRADESH JOURNAL OF ZOOLOGY

Organic pesticides, which pollute natural water through agricultural waste, draining off water and other sources, have a negative impact on fish and other aquatic organisms. The primary goal of this research was to assess and compare the acute toxicity of three types of pesticides: organochlorine (endosulfan), organophosphate (chlorpyrifos), and synthetic pyrethroid (permethrin), all of which are routinely employed in agricultural practices. These three insecticides were given to adult male and female zebrafish at random. Each insecticide was subjected to its own set of toxicological tests. For a period of 96 hours, the death rate of zebrafishes was tracked in a laboratory setting. This preclinical data gives information about the safety of drugs for human usage. The Probit Analysis Statistical approach was used to evaluate the results of the toxicological tests. The toxicity tests gave the 96-h LC₅₀ values as 0.10, 0.16 and 0.13µg/l for endosulfan, chlorpyrifos and permethrin respectively. The LC₅₀ values revealed that all the three pesticides were highly toxic and the zebrafish showed highest sensitivity towards endosulfan followed by permethrin and chlorpyrifos. The LC₅₀ values demonstrated that all three pesticides were extremely harmful to zebrafish, with endosulfan being the most sensitive, followed by permethrin and chlorpyrifos.

Prior to death, the fish showed signs of respiratory distress (such as gasping for air), loss of balance, and erratic swimming. The toxicity of these pesticides was also discovered to be time and concentration dependent. It is concluded that these insecticides are exceedingly dangerous and should be discontinued with considerable cautions. Pesticidal contamination in aquatic environments can be assessed using zebrafish (Danio rerio) as a bioindicator.