Dietary risk assessment of spinosad in China

Abstract

Spinosad is an insect control agent that is derived from a naturally occurring soil bacterium, and is effective on several classes of insects, especially Lepidoptera larvae. Spinosad consists mainly of a mixture of spinosyns A and D and is registered for uses on a variety of crops in many countries including China. In order to understand the residue behavior of spinosad and to evaluate the dietary risk of spinosad residue in food in China, a number of residue studies were conducted on cotton, Chinese cabbage and eggplant. Residue detection methods using high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection have been validated for the detection of spinosad and its metabolites in cotton, Chinese cabbage and eggplant. The proposed definition of the residue for the estimation of spinosad dietary intake is the sum of spinosyns A and D. According to existing Chinese residue studies, the Supervised Trials Median Residues (STMRs) for cotton seed, Chinese cabbage and eggplant were less than 0.010, 0.103 and 0.045 mg/kg, respectively. Daily intake of spinosad residue in food was calculated by multiplying the pertinent Chinese food consumption data with the STMRs. Establishment of spinosad acceptable daily intake (ADI) of 0–0.02 mg/kg bw was based on a No Observed Adverse Effect Level (NOAEL) of 2.4 mg/kg bw per day and a 100-fold safety factor. Therefore, only 2% of the spinosad ADI is occupied by spinosad dietary daily intake in the Chinese population. The proposed maximum residue limits (MRLs) for spinosad on cotton seed, Chinese cabbage and eggplant are 0.01, 2 and 0.5 mg/kg, respectively. Although the STMRs for cotton and Chinese cabbage are lower or equal to STMRs used by Codex, no STMR for eggplant was used by Joint Meeting on Pesticide Residues (JMPR) when dietary risk assessment was carried out for spinosad. If these Chinese residue studies were considered during the Codex risk assessment process, the International Estimate Daily Intakes (IEDIs) of spinosad in the five Global Environment Monitoring System (GEMS) regional diets would be 2–30% of the ADI (0–0.02 mg/kg bw). In conclusion, spinosad is unlikely to pose any public health issues not only in China but also in global community, if it is applied according to the good agriculture practices (GAPs) established by each countries.