シアノフェンホス(シュアサイド^[○!R])連続投与による乳牛のミルクおよび肉中における残留について Residue Study with Cyanofenphos in Milk and Meat Following the Subacute Feeding to Dairy Cattle

シアノフェンホス(シュアサイド^[○!R])連続投与による乳牛のミルクおよび肉中における残留について宮本純之, M. L. Keplinger, R. J. Wingender, 宮本善之, D. H. Jenkins (住友化学工業株式会社, Industrial BIO-TEST Laboratories).シアノフェンホス(シュアサイド)O-エチルO-4-シアノフェニルフェニルホスホノチオエートを0, 5, 15, 50ppmの割合で含んだ飼料で各群4頭の乳牛を30日間飼育し, ミルクを採取するとともに3頭を30日目に解剖して肝臓, 腎臓, 筋肉および脂肪を得た.各群残り1頭はさらに30日間正常飼料で飼育しミルクを採取したのち屠殺した.ミルク, 組織中におけるシアノフェンホスおよびシアノフェンホスオキソンをメタノール・アセトニトリル混液で抽出後FPD付きガスクロマトグラフで定量したところ, 50ppm処理区のミルク中にのみシアノフェンホスが認められ処理開始2日および4日後で最高0.25ppmに達した.オキソン体も同じく4日後に最高の0.06ppmに達したが, 両化合物ともその後減少し, 30日後では検出限界以下となった.50ppm区30日後における脂肪中のシアノフェンホスおよびオキソン体の残留量はそれぞれ平均0.9ppmおよび0.09ppmであり, 他の組織中ではこれらの残留量はその約1/10であった.15, 5ppm処理区ではミルク中の残留量はすべて検出限界以下, 組織中にもほとんど残留を認めなかった.60日後では各処理区を通じて少量(0.005ppm)のシアノフェンホスが一部の組織中に検出されたにすぎず, オキソン体はまったく存在しなかった.

Four groups of 4 dairy cows were fed a diet containing 0, 5, 15 and 50 ppm cyanofenphos, O-ethyl O-4-cyanophenyl phenylphosphonothioate (Surecide^[○!R]) for 30 days. Three cows from each group were sacrificed on day 30 and the remainders were kept on a normal diet for a 30-day recovery period. Milk samples were taken at specified intervals during the entire experimental period, and liver, kidney, muscle and fat samples were collected at sacrifices. Cyanofenphos and cyanofenphos-oxon residues in milk and tissues were extracted with methanol/acetonitrile and determined by gas chromatography on a 3% OV-1 column using a flame photometric detector. In the milk of cows the residues were found only on the 50 ppm treatment. The highest level of cyanofenphos (0.25 ppm) occurred at day 2 and 4. The oxon level (0.06 ppm) peaked at day 4. The concentration of both compounds in milk decreased thereafter, and after 30 days of feeding the residue levels of cyanofenphos and cyanofenphos-oxon were less than the detection limits. The 50 ppm treatment for 30 days resulted in residues of 0.9 ppm cyanofenphos and 0.09 ppm cyanofenphos-oxon on an average in the fat, whereas other tissues generally contained one tenth the amount of these compounds. At the lower dosages any detectable amounts of cyanofenphos or its oxon were hardly observed. At day 60, trace amounts (0.005 ppm) of cyanofenphos were sporadically detected in the tissues.