Abstract:
The field trials on terminal residue and dissipation of difenoconazole in celery were carried out in Hunan and Shandong Provinces, and the acute toxicity of 10% difenoconazole water dispersible granule (WG) on soil organisms were studied in the laboratory. Based on the residue data and toxicity endpoints, the long-term and short-term dietary intake risks of difenoconazole to different populations in China and the environmental risks to soil organisms were evaluated. The results showed that the half-life of difenoconazole in celery leaves, stems and soil were 5.2-8.8 d, 8.0-8.2 d and 13.6-15.0 d, respectively. After the formulation was applied for three times with the interval of 5 days at the recommended dosage of 120 g/hm
2, the residue of difenoconazole in celery leaves was higher than MRL (3 mg/kg, China) and the residues in celery stem and the whole celery seedling were less than MRL on the 5th day after last application. The short-term dietary intake risk quotient (RQ
a) for the general population and children aged 1-6 years were 0.09 and 0.10, respectively. The long-term dietary risk assessment results showed that the contribution rate of the residues in celery for different populations in China was 9.4%-19.8%. The primary risk of 10% difenoconazole WG to soil organism was acceptable with acute risk quotient (RQ
e) of 0.368-0.890.