Molecular Mechanisms of Pesticide Toxicity in Humans

Pesticides are chemicals designed to kill a variety of pests, such as insects, weeds, rodents and fungi generally to improve crop production. Improper and widespread usage of pesticides and usage of banned pesticides leads to neurological and haematological complications in individuals. This scenario is highly prevalent in India and other developing countries, where there is continuous usage of different pesticides, including banned ones, based on the season and crop produced. The degree of toxicity to individuals depends upon the nature of the pesticides, their environmental concentration and factors such as temperature, humidity, pH, oxygen concentration, etc. It became evident that persistent usage of pesticides had an adverse impact on the ecological communities. Since most of the pesticides are acetylcholine inhibitors and nerve poisons, this has led to a number of extensive epidemiologic investigations exploring the possible impact of their exposures on human health. The mechanism of toxicity is the inhibition of acetlycholenesterase resulting in the accumulation of neurotransmitter acetylcholine and continuous stimulation of acetylcholine receptors. Humans affected by these chemicals suffer from acute, subacute or chronic toxicity followed by neurological sequel, depending not only on the extent and route of exposure but also on the chemical structure of the compound. Aerial sprays or dusts can be rapidly absorbed through skin and mucous membranes or by inhalation causing toxicological problems. Cholinergic toxicity occurs when too much acetylcholine is present in the synapse leading to excessive parasympathetic effects. This review deals with the molecular mechanisms of cyto and genotoxicity of pesticides and their possible implications on human health.