Storage Stability, Residual Digestion and Chronic Dietary Exposure Assessment of Oxine-copper in Citrus

To evaluate the storage stability, dissipation dynamics and chronic dietary exposure risk of oxine-copper in Citrus, field trials of oxine-copper residues in Citrus were conducted in Hainan and Jiangxi Provinces. The samples were detected by high performance liquid chromatography and quantified by external standard method. The storage stability, dissipation dynamics and dietary exposure risk of oxine-copper in Citrus fruit were assessed. Results showed that, after storing at −20 ℃ for 180 d, the degradation amount of oxine-copper in Citrus fruit was less than 10%. The digestion rate of oxine-copper in the Citrus fruit was in accordance with the first-order kinetic, and the half-lives of oxine-copper in Citrus fruit were 10.2~15.1 d. According to the results of the dietary exposure assessment, the estimated daily intake of oxine-copper for all age population was 0.0891~1.4584 μg/kg·bw, and the dietary exposure risk was 0.45%~7.29%. Oxine-copper could be stably stored in citrus fruit for at least 180 d. Oxine-copper was easily degraded in Citrus. According to the usage specification of 33.5% oxine-copper suspension to control Citrus bacterial canker disease, the chronic dietary exposure risk of oxine-copper was within the acceptable range for the populations.