Arsenic Reduction in Climate-Friendly Farming
Surprisingly, environmental contaminants are commonly found in food because heavy metals, like arsenic, lead, or mercury are ordinary pollutants in the soil, water, or air where our food is grown. Mercury is found in fish, lead in fruits and vegetables, and arsenic is frequently detected in grains like rice.
Arsenic is common in rice because rice plants are naturally absorbent and typically grown in a flooded field with water potentially contaminated with heavy metals. Field flooding also boosts the solubility and mobility of arsenic found in the soil, increasing the plant’s absorption of it. Reducing total water use and time that the crop is submerged under water can drastically minimize arsenic absorption.
AgriCapture built the Climate-Friendly Rice program around sustainable farming practices that limit water consumption, reduce greenhouse gases, and preserve food quality and safety through reduction in arsenic absorption.
Limiting Arsenic and Methane: A Dual Benefit of Aeration Periods
To receive Climate-Friendly certification from AgriCapture, rice must be cultivated with aeration periods. This allows oxygen to reach the soil, ultimately reducing methane and at the same time, reducing arsenic absorption. Farmers typically implement Furrow Irrigation or Alternate Wetting and Drying (AWD) systems which result in significantly less arsenic in the grain, on top of climate benefits caused by water conservation.
Farmers growing rice with AWD flood their fields intermittently, allowing water to subside until the soil achieves an aeration, or “dry down” period before reflooding. In scientific research, AWD has demonstrated up to a 68% reduction in arsenic concentration, while maintaining yield.
AgriCapture verifies that farmers introduce drying periods, via techniques like AWD, by collecting farm records and reviewing remote sensing data. By working with farmers to analyze irrigation records and using remote sensing technology, AgriCapture can understand where, when, and how much water was applied to the field.
Arsenic Accumulation in Other Rice Systems
Conventional rice systems, which utilize a levee system to maintain a continuous flood on the field, tend to produce grain with higher arsenic content. On top of conventional rice farming, Organic is a popular cultivation system, but due to prohibiting synthetic fertilizer, pesticides, and herbicides, organic farmers must maintain a continuously flooded rice field to manage weeds and pests. The flooded fields required to grow organic rice boost the accumulation of arsenic in the grain because anaerobic soil conditions amplify the bioavailability of arsenic.
The absorption of dangerous heavy metals coupled with higher methane emissions overshadow the intended benefits of organic certification or operational advantages of conventional farming. The risk of grain arsenic increases when rice is not verified to have received an aeration period during the growing season, as AgriCapture’s Climate-Friendly Rice Certification guarantees.
Although naturally occurring in the environment, arsenic is a human carcinogen and consumption via contaminated food or water increases the risk of cancer and respiratory diseases. AgriCapture closely monitors climate-friendly farming activity, to verify reductions in methane emissions, water usage, and arsenic accumulation. The Climate-Friendly Rice program incentivizes farming techniques that improve the sustainability, quality, and safety of the rice consumed every day.
To see how AgriCapture verifies that farms introduce drying periods, via techniques like AWD, by collecting farm records and reviewing remote sensing data, watch the video:
