化粧品中のポリフルオロアルキルリン酸エステル類の好気条件下における生分解生成物の挙動

Abstract

本研究では，化粧品中のポリフルオロアルキルリン酸エステル類（PAPs）の好気条件下における生分解生成物の挙動の検討を主目的とした．PAPsは難分解性や生殖毒性が疑われているペルフルオロカルボン酸類（PFCAs）の前駆体として注目されている．下水処理場の生物処理工程を模擬した生分解試験より，化粧品中のPAPsからの類縁化合物類を含めた生分解生成物の挙動を定量的に評価した．化粧品中の10種のdiPAPsの濃度減少を一次反応式で近似した場合，その半減期は6～111時間であり，分子量が大きくなるにつれて，半減期が長くなる傾向が示された．8:2diPAPからのペルフルオロオクタン酸（PFOA）のモル生成率は4.0±0.4％であった．中間生成体と予想されるフッ素テロマーアルコール類（FTOHs）, フッ素テロマーカルボン酸類（FTCAs）が生分解生成物として検出された．さらに，低分子量のFTOHs（5:2sFTOH, 6:2FTOH, 7:2sFTOH）は，曝気により気相へ移行する可能性が示唆された．Polyfluoroalkyl phosphate esters (PAPs) are a group of anthropogenic organic fluorinated compounds which have been widely used in many products. Some researchers pointed out that PAPs are precursors of perfluorocarboxylic acids (PFCAs), which are endocrine disrupting compounds. Main objective of this study was to understand behavior of biodegradation products from PAPs in cosmetics under aerobic condition. For two different biodegradation tests, namely, 1) 8:2diPAPs and 2) a foundation which was labeled “C9-15 fluoroalcohol phosphate” were prepared. As a result, the concentrations of 10 diPAPs decreased during both experiments and they were approximated to first-order reactions. Their half-lives were 6~111 h, and when their molecular weights increased, thier half-lives became longer. Mass of the formed PFOA was 4.0±0.4% of input mass of 8:2diPAP. Not only PFCAs but also some kinds of FTCAs, FTOHs were detected, which seemed to be intermediate products of diPAPs. It was suspected that FTOHs with lower molecular weight (5:2sFTOH, 6:2FTOH, 7:2sFTOH) were diffused into the air by aeration.