Arsenic Contamination in Soil and Water Across South East Asia: Its Impact and Mitigation Strategies

Abstract

Globally, a continuous and swift increase in population raised the water demand. Due to scarcity in available freshwater resources, ground water turned out to be a key source of water for crop and human consumption. Recently, many groundwater aquifers across the world reported exceeding the limits of the prescribed arsenic level, in turn raising a serious concern on both environment and human health. Arsenic is a ubiquitous metalloid that exists in four different oxidation states inclusive of both metallic and non-metallic characteristics and occurs both in [arsenite (AsIII) and arsenate (AsV)] and inorganic (monomethylarsonic acid (MMA) and dimethyl arsenic acid (DMA)) forms. The arsenite (AsIII) form is comparatively more toxic than arsenate (AsV), MMA and DMA. Heavy accumulation of arsenite (AsIII) form in the plant tissues stimulates the production of reactive oxygen species (ROS) which in turn affects the membrane stability, permeability, enzyme activity, electron transport chain, and ion homeostasis leading to poor seed germination, growth retardation and yield reduction in plants. In general, arsenite (AsIII) form of arsenic predominates in reducing the environment that usually prevails in rice-growing tracts of the world. Rice is the staple food in South East Asian countries viz., Bangladesh, Cambodia, China, India, Myanmar, Nepal, Pakistan, Thailand, and Vietnam in turn has a growing concern about arsenic poisoning in the human food chain. In consideration of the associated damage due to arsenic accumulation, many mitigation strategies were devised by several researchers. This chapter focuses on appropriate strategies that could mitigate arsenic toxicity effectively and in a sustainable manner.