Biomarkers of Pesticide - Contaminated Environment

Abstract

Pesticide is the umbrella term for chemicals or biologicals used to control pests. The Environmental Protection Agency (EPA) defines a pesticide as any substance or mixture of substances/chemicals intended to prevent, destroy, repel or mitigate any pest (US-EPA, 2006). A pesticide need not always kill a pestː it could sterilize, or repel. Pesticides can be classified in various ways such as, by their target, chemical nature, physical state and mode of action (Ware, 2000). Classification based on the target is perhaps the most widely known as the following examples indicate; Pesticides used to manage insects are called insecticides; and those used to manage rodents are called rodenticide; those used to manage fungi are called fungicides e.t.c (Ware and Whitacre, 2004). Pesticides also include plant growth regulators, defoliants, or desiccants (Hagtrum and Subramanyam, 2006). The environmental pollution and poisoning owing to the widespread use of pesticides in agricultural and domestic pest control may be detrimental to the health of handlers, nontarget organisms and consumers. Pesticides or their residues are ubiquitous contaminants in the environmental media (air, soil, water), and in humans, plants and animal tissue samples. Pesticides uptake occurs through the skin, eyes, by inhalation, or by ingestion directly or through the food chain. The fat-soluble pesticides, and to some extent, the water-soluble pesticides are absorbed through intact skin. Sores and abrasions may facilitate uptake through the skin. The vapours of pesticides or aerosol droplets smaller than 5μm in diameters are absorbed effectively through the lungs. Larger inhaled particles or droplets may be swallowed after being cleared from the airways. A common toxic effect to the lung is the result of oxidative burden which occurs as a result of active oxidants in pesticide mixtures, especially free radicals that are generated by a variety of toxic agents and the action of lung defense cells. Much of the oxidative damage to lungs is probably done by free radicals, such as hydroxyl radical, HO·, and superoxide ion, O.which initiate and mediate oxidative chain reactions. Lungs of animals exposed to oxidants have shown elevated levels of enzymes that scavenge free radicals, providing evidence for their role in oxidative damage. There is evidence to suggest that lung cells damaged by toxicants release species that convert lung O2 to reactive superoxide anion. Pesticide ingestion can occur from the consumption of contaminated food or from using contaminated utensils. Contaminated