A recent publication by researchers at the School of Environmental Studies (SOES), Jadavpur University, reveals 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 titled ‘Arsenic accumulation in paddy plants at different phases of pre-monsoon cultivation’, published earlier this year in the peer-reviewed scientific journal Chemosphere , highlights the processes and dependencies of arsenic trans-location in rice from contaminated irrigation water.
Samples for the study were taken from the Deganga block in the State’s North 24 Parganas district, an area that’s worst affected by ground water arsenic contamination.
The study found that arsenic contamination in paddy was higher than in previous studies.
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,” Tarit Roychowdhury, Director, SOES, and corresponding author of the publication told The Hindu.
Professor Roychowdhury said the uptake of arsenic is faster in young roots in a vegetative state than in older tissues with a higher concentrations of iron in root soil in the reproductive phase.
The authors have also raised concerns over the disposal of the contaminated rice straw which is used as animal fodder or burnt or sometimes left in the field itself to serve as fertiliser.
