Raveton Muriel, Aajoud Asmae, Willison John, Cherifi Myriam, Tissut Michel, Ravanel Patrick
Equipe Pertubations Environnementales et Xénobiotiques, Laboratoire Ecologie Alpine, UMR CNRS No. 5553, Université Joseph Fourier, BP 53X, 38041 Grenoble Cedex 9, France.
Chemosphere. 2007 Oct;69(7):1124-9. doi: 10.1016/j.chemosphere.2007.03.063. Epub 2007 May 16.
Seed-coating with the insecticide fipronil has been intensively used in sunflower cultivation to control soil pests such as wireworms. A research project was undertaken to determine the soil distribution of fipronil and of its main phenylpyrazole metabolites. Under agronomic conditions, the quantity of fipronil in the seed-coat (437 microg/seed) decreased continuously during the cultivation period (3.9 microg day(-1) during the first two months; 0.3 microg day(-1) during the next four months). At the end of the cultivation period, 42% of all phenylpyrazole compounds remained in the seed-coat. Fipro nil was poorly mobile in soil, and at the end of the cultivation period it was mostly concentrated in the soil layer close to the seed (3240 microg kg(-1) soil). Starting from the seed-coating, a fipronil concentration gradient was measured in the soil, up to a distance of 11 cm from the seed. Degradation in the soil occurred at a moderate rate, probably due to the fact that water solubilization of the solid active ingredient present in the seed coating was rate limiting. Indeed, after 6 months of cultivation, only 51% of the fipronil seed-coating was found in the soil, about 7% having been absorbed by the sunflower plant, and 42% remaining in the seed coat. The predominant metabolites produced in the soil were sulfone-fipronil, sulfide-fipronil and amide-fipronil, which were produced at average rates of 5 microg kg(-1) soil day(-1), 3 microg kg(-1) soil day(-1), and 0.4 microg kg(-1) soil day(-1), respectively. In contrast, the photoproduct, desulfinyl-fipronil, was barely detected. All phenylpyrazole compounds were poorly mobile, except for the amide derivative, which is devoid of insecticidal activity in marked contrast to the other metabolites. Furthermore, detectable soil contamination was limited to a zone of about 11 cm around the seed.
用杀虫剂氟虫腈进行种子包衣已在向日葵种植中广泛用于防治诸如金针虫等土壤害虫。开展了一项研究项目以确定氟虫腈及其主要苯基吡唑代谢物在土壤中的分布情况。在农艺条件下，种子包衣中的氟虫腈量（437微克/种子）在种植期间持续减少（头两个月为3.9微克/天；接下来四个月为0.3微克/天）。在种植期结束时，所有苯基吡唑化合物中有42%残留在种子包衣中。氟虫腈在土壤中的移动性较差，在种植期结束时，它大多集中在靠近种子的土壤层（3240微克/千克土壤）。从种子包衣开始，在土壤中测量到了氟虫腈浓度梯度，直至距离种子11厘米处。土壤中的降解以中等速率发生，这可能是由于种子包衣中存在的固体活性成分的水溶化作限速因素。实际上，种植6个月后，仅在土壤中发现了51%的氟虫腈种子包衣，约7%被向日葵植株吸收，42%残留在种子包衣中。土壤中产生的主要代谢物是砜基氟虫腈、硫醚基氟虫腈和酰胺基氟虫腈，其产生速率分别平均为5微克/千克土壤/天、3微克/千克土壤/天和0.4微克/千克土壤/天。相比之下，光产物脱亚磺酰基氟虫腈几乎未被检测到。除酰胺衍生物外，所有苯基吡唑化合物的移动性都很差，酰胺衍生物没有杀虫活性，这与其他代谢物形成鲜明对比。此外，可检测到的土壤污染仅限于种子周围约11厘米的区域。
