40%稻丰散水乳剂在水稻及稻田环境中的残留动态研究

Study on the Residual Dynamic of Phenthoate in Rice and Field Environment

测定了稻丰散在水稻及稻田环境的残留动态情况。以丙酮、乙腈或二氯甲烷提取水稻、土壤及水样中的稻丰散残留,稻苗样品过SPE小柱净化,稻壳和糙米直接浓缩、定容,最后用GC-ECD(气相色谱仪带电子捕获检测器)测定。稻丰散在土壤、田水、稻杆(苗)、糙米和稻壳中的添加回收率为83.8%～117.2%。稻丰散在三地田水、土壤和稻苗中的消解半衰期分别为0.92～1.71 d、8.2～16.1 d和2.59～4.30 d。按推荐剂量的1.5倍施药3～4次,距最后一次施药间隔21 d后,稻杆中最终残留量≤0.019～2.05 mg/kg,稻壳中最终残留量≤0.234～4.19 mg/kg,糙米中最终残留量≤0.001～0.040 mg/kg。暂以稻丰散在糙米中的最高残留限量为0.05 mg/kg,糙米距采收期最后一次施药21 d是安全的,但稻壳慎用。

Residue dynamics and teminal residue of phenthoate in rice and field environment were studied; The phenthoate residue of these samples was extracted with acetone , acetonitrile and dichloromethane respectively, and straw sample were cleaned up with Solid-phase extraction, and condensed to dry. Determinations of analytes were completed using GC with ECD detection. The results showed that the recoveries of Phenthoate in soil, water, straw, unpolished grain and chaff ranged from 83.8 % to 117.2 %. The half-life of gradation for Phenthoate was 0.92 to 1.71 d in water, 8.2 to 16.1d in soil, and 2.59 to 4.30 d in straw. When the rice was sprayed with one and a half times high dosage ofphenthoate 40% EW, at the 21st day after the application, the final residues of the phenthoate were lower than 0.019-2.05 mg/kg in straw, 0.234-4.19 mg/kg in chaff, and 0.001-0.040mg/kg in unpolished grain. When phenthoate was applied at the dose, residue of the unpolished grain was lower than MRL.