Impact of Water Regimes and Amendments on Inorganic Arsenic Exposure to Rice.

Supriya Majumder,Pabitra Banik,Pabitra Kumar Biswas

doi:10.3390/ijerph18094643

Abstract

Rice-based diet faces an important public health concern due to arsenic (As) accumulation in rice grain, which is toxic to humans. Rice crops are prone to assimilate As due to continuously flooded cultivation. In this study, the objective was to determine how water regimes (flooded and aerobic) in rice cultivation impact total As and inorganic As speciation in rice on the basis of a field-scale trial in the post-monsoon season. Iron and silicon with NPK/organic manure were amended in each regime. We hypothesised that aerobic practice receiving amendments would reduce As uptake in rice grain with a subsequent decrease in accumulation of inorganic As species relative to flooded conditions (control). Continuously flooded conditions enhanced soil As availability by 32% compared to aerobic conditions. Under aerobic conditions, total As concentrations in rice decreased by 62% compared to flooded conditions. Speciation analyses revealed that aerobic conditions significantly reduced (p < 0.05) arsenite (68%) and arsenate (61%) accumulation in rice grains. Iron and silicon exhibited significant impact on reducing arsenate and arsenite uptake in rice, respectively. The study indicates that aerobic rice cultivation with minimum use of irrigation water can lead to lower risk of inorganic As exposure to rice relative to flooded practice.

Highlights

Arsenic (As) is highly toxic among the other trace elements ubiquitously found in the environment
The results strongly suggest that aerobic conditions and amendment applications effectively reduced inorganic As species concentrations in rice grain
The results indicate that aerobic rice cultivation with a special management practice has the efficacy to mitigate As accumulation in rice grains

Summary

Introduction

Arsenic (As) is highly toxic among the other trace elements ubiquitously found in the environment. As toxicity is one of the biggest calamities in the world. The source of As in the terrestrial environment is found to be natural as well as anthropogenic [1]. Groundwater contamination through naturally occurring As leads to subsequent mobilisation of As in the soil matrix. It gives rise to the potential impact on groundwater-irrigated paddies considering the source of As input into the food crops [2]. It is crucial to investigate rice As exposure in the As-contaminated rice agroecosystem continuum

Methods

Results

Discussion

Conclusion