Key Details
Controlling arsenic in drinking water alone may leave a major exposure pathway unaddressed, as contaminated irrigation and cooking water can transfer arsenic into rice and other foods consumed every day.
Key Area | Main Finding |
|---|---|
Primary Health Concern | Long-term exposure to inorganic arsenic is associated with lung, bladder and skin cancers, with stronger evidence also emerging for ischaemic heart disease. |
Risk Reference Point | JECFA selected 0.3 micrograms per kilogram of body weight per day as a reference point for assessing heart-disease risk. |
Major Food Pathway | Rice can accumulate more arsenic than many other cereals because it is commonly cultivated under continuously flooded conditions. |
Foods with Higher Concentrations | Rice, mushrooms, algae and some seaweeds recorded comparatively high inorganic arsenic concentrations. |
Kolkata Exposure Study | Estimated daily exposure was 1.06 micrograms per kilogram of body weight for adults and 1.27 for children. |
Main Contributor in the Study | Rice and other cereals accounted for 83% of adult exposure and 81% of child exposure. |
Farm-Level Response | Alternate wetting and drying can substantially reduce arsenic accumulation in rice grains. |
Household Response | Cooking rice in excess safe water and discarding the water can reduce arsenic, while contaminated cooking water can increase it. |
Arsenic Control Must Extend Beyond Drinking Water
The WHO–FAO report, Safety Evaluation of Certain Contaminants in Food, shows that arsenic exposure can continue even where households receive safe drinking water. Naturally occurring arsenic in groundwater can enter agricultural fields through irrigation, accumulate in crops and be introduced again when contaminated water is used to wash or cook food.
The assessment therefore reframes arsenic as both a water-quality problem and a food-system risk. Policies that concentrate only on drinking-water supply may reduce direct exposure while leaving irrigation, crop contamination and food preparation insufficiently addressed.
Rice Creates a High-Exposure Pathway
Rice deserves particular attention because flooded cultivation conditions make arsenic in soil more available for plant uptake. In the global food database reviewed by the Committee, average inorganic arsenic concentrations were estimated at approximately 106–112 micrograms per kilogram in rice, rising to 147 micrograms in husked rice and falling to around 78–81 micrograms in polished rice.
The wider risk depends not only on the concentration present in a food but also on how frequently and in what quantity it is consumed. A moderately contaminated staple eaten every day can contribute more to population exposure than a food containing higher concentrations but consumed only occasionally.
Inorganic Arsenic Drives the Main Health Risk
Different chemical forms of arsenic do not carry the same level of risk. The Committee found strengthened evidence linking inorganic arsenic with lung, bladder and skin cancers, alongside growing evidence of its association with ischaemic heart disease.
Joint FAO/WHO Expert Committee on Food Additives (JECFA) selected 0.3 micrograms per kilogram of body weight per day as a reference point for assessing heart-disease risk. This is not a declared safe exposure limit. It is a benchmark used to compare estimated population exposure and guide risk-management decisions.
The Kolkata Study Shows Why Food Exposure Matters
The report includes an exposure study covering the Kolkata area of West Bengal. It estimated daily inorganic arsenic exposure at 1.06 micrograms per kilogram of body weight for adults and 1.27 for children, both above JECFA’s risk-assessment reference point.
Rice and other cereals contributed more than four-fifths of estimated exposure. Importantly, the households reportedly used arsenic-free treated surface water, indicating that food exposure may persist even after the direct drinking-water pathway has been controlled.
However, the findings should not be treated as national estimates. The study covered one geographical area, included a limited number of samples analysed for specific arsenic forms and assumed that inorganic arsenic constituted 90% of total arsenic. Broader and more representative dietary studies are therefore necessary to establish the scale and distribution of risk across India.
Prevention Must Begin Before Food Reaches Consumers
The report identifies agricultural water management as an important means of reducing arsenic accumulation in rice. Alternate wetting and drying, instead of keeping fields continuously flooded, reduced grain arsenic by 41–68% in cited studies. A field trial across 24 locations in the Ganga valley also found lower arsenic availability under improved irrigation practices.
Household preparation can provide an additional layer of protection. In one study, briefly boiling rice in excess clean water, discarding the water and completing cooking with fresh water removed around 54% of inorganic arsenic from brown rice and 73% from white rice. However, the effectiveness of this method depends entirely on the use of safe water; washing or cooking rice with arsenic-contaminated water may increase the final concentration.
What Is Inorganic Arsenic?
Inorganic arsenic is the more harmful form of arsenic commonly found in contaminated groundwater, soil and foods such as rice. Long-term exposure is associated with cancers, cardiovascular disease and other adverse health effects.
It differs from several organic arsenic compounds found mainly in seafood, many of which appear to be less harmful, although evidence on some forms remains incomplete.
Policy Relevance
Integrate water and food surveillance: Arsenic monitoring needs to cover groundwater, irrigation water, agricultural soil, rice and cooked food rather than treating drinking water as the only exposure pathway.
Build arsenic-speciation capacity: Testing only for total arsenic may overstate or understate the health risk. Food-safety laboratories need the capability to distinguish harmful inorganic arsenic from different organic forms.
Prioritise affected rice-growing regions: West Bengal and other groundwater-affected regions require targeted crop monitoring, irrigation reforms and locally appropriate agricultural guidance.
Develop representative exposure data: India needs national and regional total-diet studies covering adults, children and communities with high rice consumption to determine the scale and distribution of food-based exposure.
Align household guidance with water safety: Advice on washing or cooking rice in excess water must emphasise that the method reduces exposure only when the water used is itself arsenic-free.
Support lower-arsenic cultivation: Irrigation management, suitable crop varieties and soil interventions can reduce arsenic uptake before contaminated food reaches consumers.
Coordinate across institutional boundaries: Effective arsenic control requires closer coordination among drinking-water agencies, food regulators, agricultural research institutions, health authorities and State governments.
Follow the Full Report Here: WHO–FAO: Safety Evaluation of Certain Contaminants in Food