Proceedings of UGC Sponsored National Seminar on Advances in Environmental Science and Technology, 5 th & 6 th February, 2011, Vivekanandan College, Kolkata – 700063 Page | 99 Arsenic toxicity in four different varieties of Rice (Oryza sativa L.) of West Bengal, India Piyal Bhattacharya 1,2, , A. C. Samal 1 , J. Majumdar 1 , S. Banerjee 1 , S. C. Santra 1 1 Department of Environmental Sc., University of Kalyani, W. Bengal, India 2 Kanchrapara College, North 24 Parganas, West Bengal, India e-mail: piyal_green@yahoo.co.in Abstract A green hose pot experiment was conducted on three widely cultivated high yielding varieties of rice namely Ratna, IR 50 and Gangakaveri and on one local rice variety (Tulsa) of West Bengal, India to investigate the uptake and distribution of arsenic in the different fractions of the rice plant. 5.0, 10.0, 20.0, 30.0 and 40.0 ppm or mg kg -1 dry weight of arsenic dosing (in the form of sodium arsenate, Na 2 HAsO 4 ) was applied to study the arsenic phytotoxicity in rice. The results showed that the uptake of arsenic in the rice plant varied with the different rice varieties. With the increasing concentrations of arsenic added to pot soil, the accumulation of arsenic in the rice grain was found to increase, but not necessarily in the same rate. The high yielding rice varieties were found to be higher accumulator of arsenic as compared to the studied local rice variety, Tulsa. Irrespective of the rice varieties, arsenic accumulated mostly in the root of the rice plant, followed by accumulation in the straw, husk and grain parts. In most of the rice varieties, the accumulation of arsenic in the rice grain was found to exceed the WHO recommended permissible limit in rice (1.0 mg kg -1 dry weight) at the 20.0 mg kg -1 arsenic dosing in pot soil, which is very near to the reported arsenic content of West Bengal soil (19.4 mg kg -1 dry weight). In that scenario if not mitigated, consumption of arsenic-contaminated rice will become another potent route of entrance of arsenic toxicity in the human food chain along with the present drinking water pathway. Keywords: Arsenic accumulation, Arsenic pollution, Arsenic toxicity, Rice (Oryza sativa L.), West Bengal. 1. Introduction Arsenic is a naturally occurring toxic metalloid, which can be found in all living materials, as well as in the air, soil and water. The intake of arsenic by humans occurs through contaminated water and food. The epidemiological studies show that the chronic arsenic poisoning can cause serious health effects including cancers, melanosis (hyper pigmentation or dark spots and hypo pigmentation or white spots), hyperkeratosis (skin hardening), restrictive lung disease, peripheral vascular disease (black foot disease), gangrene, diabetes mellitus, hypertension and ischemic heart disease (Guha-Mazumder et al. 2000; Srivastava et al. 2001; Rahman 2002). According to Lehoczky et al. (2002) and Norra et al. (2005) the uptake of arsenic by agricultural plants is a function of availability of arsenic (content, water requirement, soil properties) as well as physiological properties. Several crop plant species (rice, elephant foot yam, green gram, arum, amaranth, radish, lady’s finger, cauliflower, Brinjal, etc.) are reported to accumulate arsenic in substantial quantities (Duxbury et