Assessment of arsenic toxicity in rice plants in areas of West Bengal

Pot culture experiments were conducted using graded doses of arsenic (As) in order to determine the toxicity symptoms in rice plants. The As accumulation by the plant parts generally followed the order: root>stem>leaf>economic produce. Yield reduction of 80.8% was observed in treatment applying more than 60 mg kg(-1) As. The arsenic toxicity symptoms in leaf and root were observed with treatment above 40 mg kg(-1) As, while the symptoms were apparent in economic produce above 60 mg kg(-1). The phytotoxicity threshold levels were observed with yield reduction to 55.5% in tillering and 54.8% at harvesting. In field experiments of rice-green manure-rice cropping sequence, no toxicity symptoms developed but a greater extent of As accumulation in rice crops was observed. The application of green manure does not significantly reduce As accumulation in the plants. The As accumulation and translocation factors in both experiments revealed the following order of root>stem>leaf>economic produce.