Aly M A, Dauterman W C
Department of Toxicology, North Carolina State University, Raleigh 27695.
J Environ Sci Health B. 1992 Apr;27(2):113-23. doi: 10.1080/03601239209372769.
Wheat grain was treated with radiolabeled diflubenzuron at 100 ppm and stored for various periods; up to 6 months. The grain was surface washed, Soxhlet-extracted with methanol, and the residues determined. A relative constant amount of bound residues (4%), i.e., non-extractable radioactivity, was found 4 months after application and remained constant. More than 97% of the extractable radioactivity in the grain after 6 months was identified as diflubenzuron. When the bound residues were fed to rats, 47% of the administered dose was eliminated via the urine and the remainder via feces within 96 h. Diflubenzuron was the major component in the urine. Adding bound residues to housefly media resulted in a dose-dependent mortality of housefly pupae. Bound residues were biologically active, preventing the emergence of adult houseflies. Supercritical fluid extraction of the bound residues extracted 92% and 96% of the radioactivity associated with grain and feces, respectively. Only diflubenzuron was present in these extracts. The bioavailability and biological activity of bound residues of diflubenzuron have been demonstrated and the identity of the radioactivity was shown to be parent compound. Based on these findings, bound pesticide residues can no longer be ignored or overlooked in the evaluation of pesticide residues and their possible toxicological implications.
将小麦籽粒用100 ppm的放射性标记双氟苯脲处理，并储存不同时期，最长达6个月。对籽粒进行表面冲洗，用甲醇索氏提取，然后测定残留物。施药4个月后发现结合残留物（即不可提取的放射性）的量相对恒定（4%），并保持不变。6个月后籽粒中超过97%的可提取放射性被鉴定为双氟苯脲。当将结合残留物喂给大鼠时，在96小时内，47%的给药剂量通过尿液排出，其余通过粪便排出。双氟苯脲是尿液中的主要成分。向家蝇培养基中添加结合残留物会导致家蝇蛹出现剂量依赖性死亡。结合残留物具有生物活性，可阻止成年家蝇羽化。结合残留物的超临界流体萃取分别提取了与籽粒和粪便相关的92%和96%的放射性。这些提取物中仅存在双氟苯脲。已证明双氟苯脲结合残留物的生物利用度和生物活性，且放射性的身份显示为母体化合物。基于这些发现，在评估农药残留及其可能的毒理学影响时，结合农药残留物再也不能被忽视或忽略。
