Environmental Fate of Organophosphate Residues from Agricultural Soils to Fresh Farm Produce: Microbial Interventions for Sustainable Bioremediation Strategies

Abstract

The dependency of the growing population for the requirement of food has put an immense pressure on agriculture. As a direct consequence, different stakeholders especially associated with the agri-ecosystem are making concentrated efforts to enhance crop productivity. This has resulted in indiscriminate use of chemical pesticides/insecticides in agricultural fields. Pesticides are mainly used to control unwanted growth of plants (weeds) and also to control the population of pests, so that the agricultural and industrial products remain safe. In modern agriculture, several pesticides including organochlorine, organophosphate, carbamate, fungicides, herbicides, and synthetic pyrethroids are well effective in this regard. Because of their low cost of manufacturing, organophosphate pesticide (OPP) is the preferred one among them. The worldwide use of organophosphate pesticides (OPPs) in natural agri-ecosystems is now a well-documented fact. Out of five billion pounds of pesticides which are used worldwide every year, organophosphate pesticides (mostly insecticides) constitute 20–38%, and the main candidates are chlorpyrifos, dichlorvos, diazinon, dimethoate, fenitrothion, methyl parathion, monocrotophos, malathion, and profenophos. Regular use of these pesticides results in an increase in environmental and occupational exposures. During the last few decades, there is a growing concern among consumers as well as among farmers about their negative effect in human and environmental health. In spite of the efforts to shift toward organic farming practices, the residual levels of OPs in soil and water bodies are still posing a threat to environment. To eliminate the OP pesticides or reduce their concentration from the environment, development of sustainable microbial-based bioremediation strategies has been initiated in the early 1970s, and the enzymatic degradation of OPs by organophosphorus hydrolase enzymes has been well studied in this regard. Modern biotechnological inventions and recently developed omics-based techniques have further increased the effectiveness of this process.