Fate of Biotoxins in the Environment and Its Health Implications

Abstract

Biotoxins are generally referred to as toxic substances that are produced naturally and can originate either in fauna or flora. They are of animal or plant origin and produce adverse effects in humans and other animals. They enter the body by ingestion through food or water or by direct exposure in air through aerosols or by bites and stings. The degree and magnitude of biological response depends on the nature of risk factors and relative susceptibility/resistance of the host. Many toxins are biomagnified through the food chain and ultimately humans may suffer. Toxins are produced by organisms, either for defence or offence, and are sometimes used to paralyse the prey. Several biotoxins have been used as medicines as they are the most reactive molecules and in very low concentrations can react with specific target sites. Due to their specificity, some of them have been used as pharmacological tools to study the physiology of the body. Toxins produced by marine organisms are most potent and often reach the human population through food chain. The biotoxins produced by microorganisms like bacteria and fungi can also be very potent and may lead to several health hazards including allergy and mortality. In human health they cause hypotension, bradycardia, negative inotrophic effect on the heart and vasoconstriction of the skin and skeletal muscles. A lectin has been isolated which is cytotoxic and is used as anticancer agent. They also decrease bronchial and salivary secretions in low dose. Some of the important toxins discussed are, namely, okadaic acid, domoic acid, ciguatoxin, scombrotoxin, kainic acid and ibotenic acid.