Chemical pesticides were introduced as an important tool for pest control and have been used extensively in human health operations and agricultural applications since late 1940s. The wide spread use, solubility in lipids, environmental persistence and bio-magnification potential of pesticides soon precipitated health hazards in animals including wildlife. The main user of pesticides is agriculture (70-80%), but they are also used in urban areas for gardens, lawns, homes, as well as in forestry, besides industrial and commercial situation. The pesticides are also applied to kill ectoparasites in animals. Domestic animals are often raised concurrently with crop production on the same premises. These make them highly vulnerable to be exposed to farm chemicals. Among all farm chemicals, pesticides owing to their toxic potential pose the greatest hazard and are incriminated as the most common cause of poisoning in animals. Pesticides accounted for 85 (17.65%) of the 487 reported cases of poisoning in animals globally during 1986 to 1996. The poisoned animal shows clinical signs referable to nervous excitement, hypersalivation, diarrhoea and vomition. The chronic cases show myelin degeneration and neurotransmission defects.
Heavy metal toxicity
Pollution of the environment with heavy metals is a serious problem that is recognized in most countries of the world. Various anthropogenic activities such as burning of fossil fuel, mining and metallurgy, industries and transport sectors redistribute toxic heavy metals into the environment, which persist for a considerably longer period and are translocated to different components of environment including biotic segment. These toxicants are accumulated in the vital organs including liver and kidney and exert adverse effects on domestic and wild animal populations.