Inadequacy of benzo[a]pyrene as a risk indicator for PAH-contaminated rice: A comparative health risk assessment in Malaysia and Indonesia.

Abstract

Rice, a primary staple for billions, is increasingly threatened by carcinogenic Polycyclic Aromatic Hydrocarbons (PAHs), yet current food safety regulations often rely solely on Benzo[a]pyrene (B[a]P). This study assessed the contamination and health risk of 12 priority PAHs in whole paddy grains from major agricultural regions in Malaysia and Indonesia. Comprehensive analysis revealed that Malaysian rice exhibited significantly higher mean total PAH concentrations (34.70 ± 40.57 ng g-1) than Indonesian rice (13.14 ± 9.19 ng g-1). Source apportionment identified distinct pollution profiles: Malaysian contamination was linked to vehicular/fossil fuel combustion, while Indonesian sources involved biomass burning. Most critically, the health risk assessment recalculated using region-specific rice consumption rates demonstrated that B[a]P was profoundly inadequate as a risk indicator. The total carcinogenic potency (TEQ) was driven by Dibenzo[a,h]anthracene (D[a,h]A) in Malaysia (88%) and Benzo[k]fluoranthene (B[k]F) in Indonesia (88%). Crucially, the cumulative Incremental Lifetime Cancer Risk (ILCR) for Malaysian adults reached 1.33 × 10-4, surpassing the critical risk threshold of 1 × 10-4. This confirms that relying on B[a]P severely underestimates the true cancer threat, mandating a paradigm shift towards comprehensive multi-PAH standards.