Yan et al. (2025) analyzed 6,632 rice samples collected from 18 prefecture-level cities in Henan Province, China, between 2020 and 2022 for five heavy metals: cadmium (Cd), chromium (Cr), lead (Pb), total mercury (Hg), and inorganic arsenic (iAs). The study found that inorganic arsenic had the highest detection rate (99.59%) and median concentration (0.110 mg/kg), with a hazard quotient exceeding 1 for all age groups — making it the dominant health risk in Henan rice, particularly for children and toddlers. All samples met China GB 2762-2017 food safety limits for Pb, Hg, As, Cr, and iAs, except for Cd, for which some exceedances were observed.
Key numbers
All concentrations in mg/kg dry weight (rice grain), ICP-MS analysis.
Detection rates and median concentrations (n = 6,632):
- iAs: detection rate 99.59%; median 0.110 mg/kg (110 µg/kg)
- Cd: detection rate 27.69%; median 0.002 mg/kg (2 µg/kg); urban mean 0.015 mg/kg; southern region mean 0.020 mg/kg (highest)
- Cr: detection rate 22.57%; median 0.015 mg/kg; eastern region highest detection rate 32.7%
- Pb: detection rate 2.25%; median 0.025 mg/kg
- tHg: detection rate 1.95%; median 0.002 mg/kg
GB 2762-2017 limits for reference: Pb 0.2 mg/kg, Hg 0.02 mg/kg, iAs 0.2 mg/kg, Cd 0.2 mg/kg, Cr 1.0 mg/kg.
Cd exceeded limits in some samples; all other metals met limits across the 6,632 samples.
Health risk (Hazard Quotient > 1): iAs HQ exceeded 1 in all age groups; toddlers had highest exposure per unit body weight.
Urban vs. rural: Cd detection rate 30.42% (urban) vs. 23.13% (rural), p < 0.001.
Comparison with other Chinese provinces: Cd and Cr levels in Henan are lower than most other Chinese provinces; As in Henan is lower than Hunan but higher than Jiangsu, Heilongjiang, and Fujian.
Methods (brief)
6,632 rice samples collected 2020–2022 from 18 Henan prefecture-level cities via market sampling (supermarkets, wholesale markets, shopping centers, farmers’ markets). Analytical method: ICP-MS for all five metals. Non-detect handling: LOD/2 substitution. Health risk assessment per USEPA guidelines using estimated daily intake (EDI) and hazard quotient (HQ) for three age groups (adults, children, toddlers). Statistical analysis: IBM SPSS 26.0; chi-square test for detection rate comparisons by region and urban/rural strata.
Note: The paper reports iAs (inorganic arsenic) directly, not total arsenic — appropriate speciation distinction preserved.
Implications
Certification: iAs at 0.110 mg/kg (110 µg/kg) median exceeds FDA Closer to Zero action level for infant rice cereal (100 ppb iAs). Sourcing Henan rice for infant products carries documentation risk.
Courses: Henan iAs profile illustrates why geography matters within China — low Cd relative to Hunan but elevated As relative to eastern coastal provinces.
App: Rice from Henan Province (CN): iAs status populated; Cd low but detectable. Regional flag warranted for iAs.