Arsenic contamination in paddy is rising in Bengal

• According to recent study conducted by researchers at the School of Environmental Studies (SOES), Jadavpur University, reveals arsenic contamination in paddy is rising from ground water in West Bengal.

Important highlights:

• It is not only rise in arsenic contamination of paddy plants from ground water in West Bengal, but also that concentration of ‘arsenic accumulation’ depends on the variety of paddy and its stage in the crop cycle.
• The study shows that arsenic uptake in the paddy plant reduces from root to grain, and that its concentration is related to the variety of the rice cultivated. The study was carried out on two commonly consumed rice varieties — Minikit and Jaya — and the latter was found to be more resistant to arsenic.
• The highest concentration was observed in the initial or vegetative state in the first 28 days. It reduced during the reproductive stage (29-56 days) and again increased in the ripening stage.

About Arsenic:

• Arsenic is an odourless and tasteless metalloid widely distributed in the earth’s crust. Arsenic and its compounds occur in crystalline, powder, amorphous or vitreous forms. It usually occurs in trace quantities in all rocks, soil, water and air. It is the 26th abundant element in the earth's crust.

Sources of Arsenic:

• Natural – Leaching of ambient arsenic in groundwater from sediments containing arsenic bearing minerals; leaching and percolation of arsenic in soils.
• Anthropogenic – Agrochemicals, wood preservatives, industrial sources, mineral processing, acid mine drainage, burning of fossil fuels etc.

Health effects:

• Arsenic occurs in inorganic and organic forms. Inorganic arsenic compounds (such as those found in water) are highly toxic while organic arsenic compounds (such as those found in seafood) are less harmful to health.
• The immediate symptoms of acute arsenic poisoning include vomiting, abdominal pain and diarrhoea. These are followed by numbness and tingling of the extremities, muscle cramping and death, in extreme cases.
• The first symptoms of long-term exposure to high levels of inorganic arsenic (e.g. through drinking-water and food) are usually observed in the skin, and include pigmentation changes, skin lesions and hard patches on the palms and soles of the feet (hyperkeratosis). These occur after a minimum exposure of approximately five years and may be a precursor to skin cancer.
• In addition to skin cancer, long-term exposure to arsenic may also cause cancers of the bladder and lungs. The International Agency for Research on Cancer (IARC) has classified arsenic and arsenic compounds as carcinogenic to humans, and has also stated that arsenic in drinking-water is carcinogenic to humans.
• Other adverse health effects that may be associated with long-term ingestion of inorganic arsenic include developmental effects, neurotoxicity, diabetes, pulmonary disease and cardiovascular disease. Arsenic-induced myocardial infarction, in particular, can be a significant cause of excess mortality. In China (Province of Taiwan), arsenic exposure has been linked to “blackfoot disease”, which is a severe disease of blood vessels leading to gangrene. This disease has not been observed in other parts of the world however, and it is possible that malnutrition contributes to its development.
• Arsenic is also associated with adverse pregnancy outcomes and infant mortality, with impacts on child health1, and there is some evidence of negative impacts on cognitive development.

By: Vishal