Groundwater pollution with arsenic in the affected belt of West Bengal and Bangladesh showed elevated arsenic in soil,groundwater,paddy,and other plants,thereby causing hazardous effect for human consumption.Early symptoms of arsenic poisoning are skin disorder,weakness,languor,anorexia,nausea,etc.Long-term exposure causes diarrhea,edema,skin pigmentation,melanosis,hyperkeratosis,enlargement of liver,respiratory disease and skin cancer.Solubility,bioavailability and toxicity of arsenic depend on its oxidation state and form.Arsenite is more toxic than arsenate,monomethyl arsonous acid and dimethyl arsenic acid.Proportion of soluble arsenite in soil increases with diminishing Eh and increasing pH when OH"ion causes displacement of arsenite and arsenate from common binding sites via ligand exchange.The remedial measures for reduction of As in soil-water-plant-human continuum include conjunctive use of water,enhancing water use efficiency,preferring low-water requiring cropping sequences,especially during summer,using manures,inclusion of legumes and application of Zn/ Fe/Si salts,phyto-and bio-remediation,mass awareness.
展开▼
