BEWARE OF THAT MAACHH-BHAAT
In Bengal, they say even the most exacting of palates can be satiated with a hearty meal of maachhbhaat, or fish and rice. However, in a pincer attack of sorts, both face a threat of contamination by chemical poisoning. While arsenic in its inorganic form, occurring in soil and groundwater, is the blight that is poisoning varieties of paddy, mercury in water and the use of formalin are the villains infecting fish. Alarms raised in either case have failed to elicit an appropriate response.
It’s known since the 1980s that large swathes of West Bengal fall in the naturally arsenic-contaminated Ganga-Brahmaputra-Meghna basin. Groundwater infected by arsenic and its consumption has been a major health concern for long. The entry of arsenic in the food chain through its presence in paddy grain has been established in research by scientists of the School of Environmental Studies (SOES) in Jadavpur University for the past several years. Dr Tarit Roychowdhury, senior faculty member of the school and water expert, who has studied arsenic contamination in soil and water and its effects on crops and vegetables, found out that eight rice-producing districts— North and South 24 Parganas, Nadia, Howrah, Hooghly, Bardhaman, Malda and Murshidabad—lie in the state’s arsenic belt. Arsenic is listed as Group 1 carcinogen by the International Agency for Research on Cancer. It’s linked to cancers of the skin, liver and kidney and can cause miscarriages and stillbirths. Crops contaminated with arsenic can, in the most alarming projection, slow-poison a mass of human population. Arsenic as an inorganic chemical is found in groundwater at a shallow depth of 40 metres. Most shallow tube -wells of Bengal are between 20 feet and 100 feet.
Crop contamination happens when arsenic-laden groundwater is used for irrigation. Thus, pre-monsoon paddy cultivated with groundwater runs a high risk of getting polluted with arsenic. According to agricultural research, rice paddy can absorb arsenic 10 times more than wheat and barley, because its roots are required to stand in flooded fields for a considerable period, resulting in maximum absorption of arsenic. While studying the progress of arsenic from root to shoot, Roychowdhury has observed that while its mobility is highest at the roots, other parts of the plant are also susceptible to the carcinogenic effects of the chemical. Studies have revealed that the edible rice grain has the least amount of arsenic accumulation in comparison to leaves and the shoot, but still contains 50-1000 ppb (parts per billion) of arsenic, whereas the prescribed limit of inorganic arsenic by the European Commission (2015) and Codex Alimentarius Commission (2014) is 100-200 ppb depending on different geo-environmental conditions.
This is not all. Paddy shoots, used as food for livestock, thus contain a high percentage of arsenic, putting at risk the animals and humans who consume the meat/ milk of cows and goats. According to Roychowdhury, a study on livestock, mainly cows, has revealed that cow milk, dung, urine and tail hair have traces of arsenic. While infected goat meat contains an arsenic concentration of 89-124 ppb, chicken meat contains 51 to 163 ppb. Worryingly, if arsenic present in cow urine/ dung gets mixed with the soil, it can recharge the arsenic table and start a vicious cycle of contamination, says Antara Das, senior research fellow, SOES.
In contrast to arsenic poisoning, humans are squarely responsible for the chemical contamination of fish, and it comes from formalin, or formaldehyde dissolved in water, otherwise used as a disinfectant in industries as well as to embalm and preserve corpses.
West Bengal’s ministry of fisheries has asked the Andhra Pradesh government to watch out for the use of formalin for preservation of Rohu and Katla fish being caught from Nagarjun Sagar, Bhimavaram, Srisailam and Koleru lake reservoirs. Andhra, the largest fish-producing state in India, exports the majority of its produce to the Bengal market.
Fish transported to West Bengal needs refrigeration twice on its way. Refrigeration of one batch of 40-50 kg fish requires 10 kg ice. The use of formalin reduces that requirement by half. Formalin is injected in the abdominal region of fish, contaminating them thoroughly. Their appearance, however, is unaffected. Officials in the state fisheries department admit that some unscrupulous fish traders often use formalin to preserve fish, but claim that surprise raids have reduced the habit.
Again, many fish farmers use leather extracts and leather waste as fish feed. Leather waste is laden with chromium, lead and zinc, which are heavy metals and toxic chemicals. “These heavy metals get accumulated in the muscle, as they are not fat-soluble, unlike most pesticides. This is a bigger threat,” says an expert from the ministry of fisheries. Though there has been increased surveillance to curb the practice, experts are sceptical if it can be stopped completely. “I know many fish ponds in North 24 Parganas where tangra (mystus cavasius) and other fish are made to nibble at leather waste to help them grow in size,” says a state government official.
The threat of contamination of fish also comes from mercury, another toxic chemical, which occurs in abundance in industrial and medical effluents dumped in rivers and water bodies. Mercury gets transformed into the highly toxic methyl mercury through microbial action and settles on water planktons, which are food for small fish. Bigger fish consume smaller fish, and are in turn eaten by humans, thus entering the food chain. The human nervous, digestive and immune systems can be severely damaged by the intake of mercury through food. Though mercury contamination of fish was brought to the state government’s attention by NGOs a decade earlier, some experts say the situation is not grave. Others say the ingress of sea water during high tide significantly dilutes any such contamination in the rivers in south Bengal.
Is this concatenation of alarming facts food for thought for the average Bengali content with her maachh-bhaat? Hopefully, she will stop to think before digging into her comfort food. ■
PADDY SHOOTS, USED AS FODDER, CONTAIN ARSENIC, THUS PUTTING AT RISK HUMANS WHO CONSUME THE MEAT/ MILK OF COWS AND GOATS