Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. 
Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. What was studied?
The study was motivated by the lack of evidence linking arsenic in rice, rather than in water, to measurable genotoxic harm in humans. Researchers conducted a cohort study in West Bengal, India, where rice is a dietary staple, and drinking water arsenic exposure was minimal. The primary endpoints were arsenic concentrations in cooked rice and urine, and the frequency of micronuclei (MN) in urothelial cells, a recognized biomarker of chromosomal/genetic damage and predictive of cancer risk. Arsenic concentrations in rice, urine, and water were measured using standardized analytic methods, and genetic damage was assessed via the MN assay in urine-derived urothelial cells. The analysis included extensive control for potential confounders such as age, sex, tobacco use, body weight, and water arsenic exposure.
Who was studied?
The study population comprised 417 adults (both men and women) from rural West Bengal, India, who had consumed rice as a staple for at least six months and whose household drinking water arsenic concentrations were below 10 µg/L, ensuring minimal non-rice arsenic exposure. Participants were recruited from three districts with varying irrigation water arsenic levels—Murshidabad (very high), Nadia (high), and East Midnapur (low). The groups were demographically comparable in terms of age, sex, body weight, tobacco use, and time spent at home, minimizing confounding from these variables. The rice consumed was predominantly locally grown, and participants’ rice and water intake were carefully quantified. Exclusion of individuals with significant travel or other potential sources of arsenic exposure further controlled for confounding. The study design thus enabled a focused assessment of the health impacts of arsenic in rice, independent of waterborne arsenic exposure.
Most important findings
| Critical Points | Details |
|---|---|
| Arsenic in rice is a major exposure route in this population | Urinary arsenic levels strongly correlated with cooked rice arsenic (r² = 0.81), confirming rice as the dominant exposure source. |
| Genotoxic effects observed above specific rice arsenic thresholds | Groups consuming rice with >200 µg/kg arsenic had significantly higher MN frequencies (genetic damage) than those consuming less. |
| Dose-response relationship between rice arsenic and genotoxicity | MN frequency increased monotonically with rice arsenic; robust statistical tests confirmed significance above 200 µg/kg. |
| Findings independent of confounders | Age, sex, tobacco use, body weight, area, and water arsenic were not significant confounders; tobacco use had only a minor effect. |
| Inorganic arsenic proportion in rice is high | About 88% of rice arsenic was inorganic, the form most toxic to humans, and this proportion was relatively uniform across samples. |
| Current regulatory thresholds may be insufficient | Genotoxic effects were seen at daily inorganic arsenic intakes slightly below the former WHO PTWI (2.1 µg/kg-bw/day); supports EFSA/JECFA moves to tighten standards. |
| Large population at risk globally | Over 3 billion people eat rice as a staple; significant portions of rice worldwide exceed the 200 µg/kg threshold found risky. |
| Rice irrigation source affects arsenic content | High-arsenic irrigation water was linked to elevated rice arsenic; only 2% of rice from low-arsenic areas exceeded the 200 µg/kg level. |
| MN frequency is a meaningful predictor of cancer risk | Previous meta-analyses confirm that MN frequency is linked to increased cancer risk, underlining the public health importance. |
| Management strategies exist to reduce risk | Cooking methods, water source, rice cultivar selection, and agricultural practices can mitigate arsenic exposure from rice. |
Key implications
The findings from this study demonstrate that high arsenic in rice is associated with elevated genotoxic effects in humans, providing direct evidence that rice with arsenic concentrations above 200 µg/kg poses a significant health risk even when waterborne exposure is minimal. This underscores the need to re-evaluate and potentially tighten heavy metal certification limits for rice, especially in regions with high-arsenic irrigation. The study supports regulatory revisions, such as those by EFSA and JECFA, and highlights the urgent need for mitigation strategies and routine testing under programs like HTMC.
Citation
Banerjee M, Banerjee N, Bhattacharjee P, Mondal D, Lythgoe PR, Martínez M, Pan J, Polya DA, Giri AK. High arsenic in rice is associated with elevated genotoxic effects in humans. Sci Rep. 2013;3:2195. doi:10.1038/srep02195
Arsenic is a naturally occurring metalloid that ranks first on the ATSDR toxic substances list. Inorganic arsenic contaminates water, rice and consumer products, and exposure is linked to cardiovascular disease, cognitive deficits, low birth weight and cancer. HMTC’s stringent certification applies ALARA principles to protect vulnerable populations.
