Human health risk mitigation from arsenic in rice by crop rotation with a hyperaccumulator plant
Exposure to arsenic (As) from a diet of contaminated rice is a widespread problem and a serious concern in several parts of the world. There is a need to develop sustainable, effective, and reliable strategies to reduce As accumulation in rice. Our goal was to develop and test a simple crop rotation method of alternating rice with the As hyperaccumulator plant, Chinese Brake fern (Pteris vitatta) to reduce As concentrations in rice grains. A greenhouse column study was performed for 2 years using As-contaminated rice paddy soil from West Bengal. Rice was grown under flooded conditions and irrigated with As-contaminated water to simulate field conditions. Chinese brake fern was grown between two rice cycles in experimental columns, while control columns were left unplanted. Our results show that at the end of two cycles, there was a statistically significant decrease in soil As concentrations in the treatment columns compared to the control columns. After one rotation with the fern, there was a significant decline in As concentrations in rice grains in treatment plants, and a concomitant decline in both non-carcinogenic and carcinogenic health risk. Our results indicate that there could be substantial benefit in implementing this simple crop rotation model to help lower human health risk from As exposure via rice ingestion.