According to the Guidelines for Health Risk Assessment of Pesticide Applicators, the risk characterization stage of pesticide health risk assessment is judged whether the health risk of applicators is acceptable through comprehensive analysis and comparison of the results of the hazard assessment stage and the exposure assessment stage.
Whether the health risk is acceptable can be judged by the risk factor, which is the ratio of exposure to AOEL, which is calculated as follows:
where: exposure—Exposure, expressed as pesticide exposure per unit body weight of the applicator in milligrams per kilogram (mg kg).
AOEL - Applicator Allowable Exposure, expressed as pesticide exposure per unit weight of applicator in milligrams per kilogram (mg kg);
rq - risk factor.
According to the requirements of health risk assessment, the risk factors of percutaneous exposure and inhalation exposure should be calculated separately for different levels of protection. Generally, the risk coefficients of percutaneous exposure and inhalation exposure are combined to obtain a comprehensive risk coefficient.
If there is data suggesting that toxicity is different between the two routes of exposure (e.g., in the case of different target organs), the risk factors of the two routes of exposure should not be combined. For mixed preparations, it should be determined according to the results of toxicology tests, and if the toxicity caused by each active ingredient is different, the risk factor Rq of each active ingredient does not need to be summed.
Where the risk factors are calculated together, the comprehensive risk factors are used to make judgments. If the composite risk factor is <1, the health risk is acceptable;If the composite risk factor is 1, the health risk is not acceptable.
If the risk factors are not calculated together, the risk factors of a single exposure route are used to make judgments. If all risk factors are <1, the health risk is acceptable;If the risk factor of any of the exposure routes is "1", the health risk is unacceptable.
Basic concepts
Risk factor RQ: The ratio of the amount of exposure to the allowable exposure of the applicator.