Prioritization of pesticides in crops with a semi-quantitative risk ranking method for Taiwan postmarket monitoring program

A risk-based prioritization of chemical hazards in monitoring programs allows regulatory agencies to focus on the most potentially concerned items involving human health risk. In this study, a risk-based matrix, with a scoring method using multiple factors for severity and probability of exposure, was employed to identify the pesticides presented in crops that may pose the greatest risk to human health. Both the probability of exposure and the severity were assessed for 91 pesticides detected in a Taiwanese postmarketing monitoring program. Probability of exposure was evaluated based on the probability of consumption and evidence of pesticide residues in crops. Severity was assessed based on the nature of the hazard (i.e., the description of toxic effects), and the acceptable daily intake (ADI) reported by available toxicological reports. This study showed that the nature of the hazard and probability of consumption had the strongest contribution to risk score. Dithiocarbamates, endosulfan, and carbofuran were identified as the pesticides with the highest concern for human health risks in Taiwan. These pesticides should be monitored more frequently than others in crops during the postmarketing monitoring program. However, some uncertainties shall be noted or improved when this methodology is applied for risk prioritization in the future.