Microplastic contamination in Kerala’s paddy fields raises food security concerns

A recent study has revealed significant microplastic (MP) contamination in Kerala’s paddy fields, raising concerns over its potential impact on agriculture and food security.

The study conducted by researchers C. Amaneesh, Hee-Sik Kim, and Rishiram Ramanan has found high levels of polyethylene (PE) and polypropylene (PP) fragments in the surface water of rice fields cultivating Pokkali and Uma varieties.

The research, published in Environment Monitoring and Assessment, shows that MP concentration was three times higher during the vegetative (transplantation) phase than in the ripening phase.

Mr. Ramanan, assistant professor, Environmental Science department, said that the density was recorded at 1,370 fragments/meter cube in Pokkali fields and 1,110 fragments per meter cube in Uma fields during transplantation, dropping to 400 and 37 fragments per meter cube, respectively, near harvest. He said that during the study, surface water was collected instead of soil, which is usually found with higher microplastic.

Further, the study examined the ecotoxicity of MP and plastic leachates (PL), which are chemicals that seep out of plastic products into the environment, on paddy field Phytoplankton.

Mr. Ramanan said that while microalgae (Chlorococcum) exhibited a temporary growth boost, cyanobacteria (Synechococcus) faced significant oxidative stress, indicating possible disruption in the ecosystem balance. Microplastic was found to be adversely affecting the growth of cyanobacteria. The finding suggests that MP pollution may favour certain resilient species, altering phytoplankton communities and potentially affecting rice productivity.

He said that with phytoplankton playing a crucial role in crop health, the researcher warned that MP contamination in paddy fields could pose a serious threat to food security and environmental sustainability.

Dr. Ramanan said the study on microplastic pollution began in 2018, with sample collection starting in 2021-22. The research focused on the Kuttanad region, where both Pokkali and Uma rice are cultivated. He pointed out that 60% of Kerala’s population consumes Uma rice, while Pokkali, known for its salt tolerance and high nutritional value, is grown in coastal regions. The proximity of Kuttanad to Kochi’s urban environment makes it more susceptible to plastic pollution, he added.

The study highlights the urgent need for measures to curb plastic pollution in agricultural landscapes to ensure long-term food security and environmental sustainability.