Cumulative dietary risk assessment of organophosphate pesticides: A comparison of hazard index and relative potency factor-based approaches
Journal
Food Control
Journal Volume
188
Start Page
112237
ISSN
0956-7135
Date Issued
2026-10
Author(s)
Abstract
Organophosphate pesticides (OPs) remain important contributors to pesticide residues in fruits and vegetables and are of concern because many share a common toxicological mechanism, acetylcholinesterase (AChE) inhibition. Conventional single-chemical risk assessment may therefore underestimate or mischaracterize health risks arising from combined dietary exposure, especially when residue datasets contain a high proportion of non-detects. In this study, we conducted both conventional and mechanism-based cumulative dietary risk assessments of 19 AChE-inhibiting OPs in Taiwan, using methamidophos as the index compound. To reduce uncertainty associated with left-censored residue data, we applied a Bayesian inference framework coupled with probabilistic simulation. Under deterministic upper-bound assumptions, cumulative exposure reached 108.9% and 148.3% of the acceptable daily intake (ADI) at the 95th and 99th percentiles, respectively. In contrast, probabilistic cumulative modeling indicated substantially lower risk, with only 0.92% of simulated individuals exceeding the methamidophos-equivalent ADI. Comparison of the conventional hazard index (HI) and relative potency factor (RPF)-based approaches showed that the HI method was more conservative, identifying 8.5% of individuals as exceeding the level of concern. ToxPi-based prioritization further identified citrus fruits as high-priority commodities for surveillance. Overall, the cumulative dietary risk of OPs in Taiwan appears low, although children exhibited relatively higher exposure than the general population. Nevertheless, these results should be interpreted cautiously because food processing factors were not considered, residue data were derived from a regional monitoring program, and biomonitoring data were unavailable for validation. These findings support a tiered framework in which the HI approach is used for initial screening and refined mechanistic cumulative assessment is used for regulatory decision-making.
Publisher
Elsevier BV
Type
journal-article