Arsenic load in rice ecosystem and its mitigation through deficit irrigation

Area of Science:

• Agricultural Science
• Environmental Science
• Food Science

Background:

• Rice is a primary source of arsenic intake for rural populations in eastern India.
• Irrigation water is a major pathway for arsenic contamination in the rice food chain.
• Understanding arsenic accumulation in rice genotypes like Shatabdi is crucial for food safety.

Purpose of the Study:

• To investigate arsenic load variations in rice (genotype Shatabdi) under different irrigation scenarios.
• To assess the impact of deficit irrigation practices on arsenic accumulation in rice plants.
• To determine the relationship between arsenic levels in water, soil, and rice.

Main Methods:

• Field survey of arsenic levels in rice, irrigation water, and soil.
• Application of deficit irrigation techniques: intermittent ponding (IP), saturation (SAT), and aerobic (AER).
• Analysis of arsenic translocation from roots to shoots and its concentration in different plant parts.

Main Results:

• Arsenic content in irrigation water and soil significantly influences arsenic load in rice grains.
• Irrigation water has a greater impact (10% higher) on grain arsenic than soil.
• Saturated and aerobic conditions reduced yield and arsenic load, while IP decreased grain arsenic with minimal yield loss.
• Deficit irrigation reduced polished rice arsenic by 17.6-25%, falling below toxic levels.

Conclusions:

• Deficit irrigation, particularly intermittent ponding, is an effective strategy to reduce arsenic content in rice grains.
• This approach can significantly lower dietary arsenic exposure without substantial yield reduction.
• Managing irrigation practices is key to mitigating arsenic contamination in rice-based food systems.