Health Aspects of Organophosphorous Pesticides in Asian Countries

Article excerpt

Abstract

Organophosphorous (OP) pesticides are used frequently in agriculture, particularly in Asian countries over the past decades. Poisoning by these agents, either as acute or chronic in these nations, is a serious health problem. OP pesticides residue in fruits and vegetables that may not induce early clinical features, could also affect the human health. Therefore, medical and health professionals should be aware and learn more on the toxicology, prevention and proper management of OP poisoning. The well-known mechanism of OP toxicity is the inhibition of acetyl cholinesterase, resulting in an accumulation of acetylcholine and continued stimulation of acetylcholine receptors. Therefore, they are also called anticholinesterase agents. Determination of blood acetyl cholinesterase and butyryl cholinesterase activities remains a mainstay for the rapid initial screening of OP pesticides. Quantitative analysis of OP and their degradation products in plasma and urine by mass spectrometric methods is a more specific method, but is expensive and limited to specialized laboratories. Therefore, history of OP pesticides exposure and clinical manifestations of a cholinergic syndrome is sufficient for management of the exposed patients. However, electrophysiological tests may be required for the diagnosis of delayed neuropathy of OP poisoning. The standard management of OP poisoning includes decontamination, atropine sulphate with an oxime. Recent advances focus on blood alkalinisation and magnesium sulphate as promising adjunctive therapies. Preventive measures in OP exposure are of great importance in human health in developing countries. Therefore, regulations and controls on safe use of OP particularly in Asian countries are recommended.

Keywords: Health, Organophosphorous, Toxicity, Poisoning, Pesticides residues, Asia

Introduction

Background

Over the past decades, organophosphorous (OP) pesticides were commonly used in agriculture, especially in Asian countries. Organophosphorous pesticides poisoning, either in its acute or chronic forms is a serious health threat. Although OP pesticides residues in fruits and vegetables may not induce early clinical features, nonetheless they could still affect the human health (1, 2). Hence, raising awareness among medical and health professionals is imperative. This awareness should not only cover the toxicology behind poisoning, but it should also include methods of prevention and appropriate management of OP poisoning.

How this review article was prepared

This review was prepared based on the experience of the fist author and the available literature between 1980 and 2011. Pub Med was searched with different names of organophosphorous, organo- phosphate, pesticides, insecticides and search terms including human exposure, organophosphorous pesticides poisoning and its complications. The first author's collections of literature on OP including the books, monographs and historically relevant articles were also used for this review. It was aimed to describe the brief basic chemistry and toxicology of OP as well as its clinical effects and long term complications. Special attention was given to the studies and reports from Asian countries. Therefore, relevant references were selected and the headings and subheadings were chosen based on the above objectives. This is neither a Meta analysis nor a critical review on OP. Herein we present a descriptive text on health aspects of OP for health professionals with special reference to the Asian countries.

History and size of the problem

Aside from the large scale use of OP pesticides in agriculture, OP compounds have also been used as chemical warfare agents (tabun and sarin) by the Iraqi army against the Iranian troops (Majnoon Island) and civilians in Halabjah (1). A few OP compounds (glyphosate, merphos) are used as herbicides, but they are structurally different from the OP pesticides (2).

Von Hofmann synthesized an OP compound called methyl phosphor chloride in 1837. …