ARSENIC CONTAMINATION IN RICE TO BE NEUTRALISED

Researchers in West Bengal have succeeded in developing a new strain of rice capable of resisting arsenic contamination in vast areas where the groundwater has been affected by chemical poisoning.

According to Agriculture department sources, scientists working on the project for over a decade have reported their findings to the central Government, which asked for certain clarifications. Responses have been sent. It is hoped that the centre will give its permission towards the promotion of the arsenic–resistance strain of rice, to be called ‘Muktosree’, shortly. 

Bangladesh authorities are already in touch with officials in West Bengal to explore possibilities of introducing this variety in their country. The person being credited with making this breakthrough is Dr Bijan Adhikari, who has been carrying out his research in the Chisurah Rice Research Centre in West Bengal and at Lucknow’s Botanical Research Institute, for some years. Experts are hopeful that the use of the new variety will bring major relief to agriculturists as well as common people in most countries which have reported the presence of arsenic in their groundwater resources. These include Australia, Chile, the US, China, Mexico, Peru, Hungary, Thailand and Viet Nam.

In India, the problem first came to light in 1976, at a time when manually operated pumps and spring water were being used in cultivation, along with tubewells. Later the problem of groundwater contamination was also reported from parts of Haryana, and Himachal Pradesh as well. In West Bengal, arsenic contamination was first reported in 1983. The first survey showed that 22 villages in 5 districts were affected. However, this turned out to be an underestimation. It was found that 3417 villages in 111 blocks were affected, shortly afterwards.

Latest studies put the figure of people suffering from medical problems related to prolonged exposure to arsenic poisoning to be around 50.4 million, or just over 50% of the state’s population. No fewer than nine districts were affected. In neighbouring Bangladesh, the same problem was noticed in a more virulent form, if anything. Here, many provinces in the country had reported the problem and no fewer than 80 million people were found acutely vulnerable. The scale of the contamination and the magnitude of the medical emergency made it clear that in the Bangladesh/West Bengal belt, the problem of mass poisoning by arsenic contamination of groundwater as well as in water used for irrigation, had emerged as the world’s most critical medical challenge. 

As experts point out, even the more celebrated and better researched medical disasters like the Bhopal gas tragedy of 1984 or the Chernobyl( in Ukraine) nuclear reactor explosion of 1996 , pale into insignificance in terms of negative long term damage and impact. For a long time it was suspected that uncontrolled use of groundwater resources, causing a continual fall in the water table, was the prime cause of sub soil arsenic coming in touch with the groundwater and mixing with it.

While symptoms of arsenic poisoning among persons affected began with skin sores that seemed incurable, the problems mounted exponentially in the absence of an agreed systematic, sustained treatment. As large scale areas were affected in both countries, the problem became critical as the main rice crop grown in both countries was found to be full of arsenic! The permissible limit of arsenic in the human body is around 50 ppb( parts per billion). But in the West Bengal/Bangladesh areas, levels as high as 150 to 200 were common in most places. 

The results for consumers of local rice was a rapid growth of cancerous tumours or infections on the skin eventually affecting their lungs, liver , bladder and pancreas, bringing an early death for most victims. Economic factors also played a role. It was seen that better off people enjoying a more substantial and balanced diet in contrast to the normal fare for the poor, tended to escape with only minor physical damage.

Medical research continued throughout the 1990s to the present times. The United Nations and other agencies earmarked a $52 million special medical programme and assistance to Bangladesh. A interesting way to reduce the extent of arsenic affliction was found by local and international experts. Experiments in Bangladesh demonstrated that iron plaque deposited at the roots of rice plants at irrigated fields through a chemical process could significantly bring down the levels of arsenic traces or presence. This phenomenon was most noticeable during the last month of the 4–month rice production cycle. Also, widespread floods caused by heavy monsoon showers ,by washing away quantities of arsenic, could help the situation improve.

On the other hand, the practice of resorting to boring tubewells or even the random digging of ponds to store water, could cause problems. In ponds. carbon settled at the bottom , steadily seeping underground, where microbes metabolised it , resulting in a mobilisation of sub soil arsenic into the soil. In rice, traces of both organic and inorganic arsenic can be found. In India the contamination of the inorganic variety is more common.

Mr Purnendu Bose, Minister for Agriculture, appreciating the breakthrough, said the state Government would arrange to provide farmers with the seeds of the special Muktosree strain of rice as soon as the centre sent its approval. Eventually it could be sold in the open market, he said.