Department of Environmental Sciences, P.O. Box 65, FI-00014 University of Helsinki, Finland.
Sci Total Environ. 2011 Jul 15;409(16):3043-8. doi: 10.1016/j.scitotenv.2011.04.036. Epub 2011 May 18.
Potential of perfluorooctanoic acid (PFOA) to degrade via indirect photolysis in aquatic solution under conditions representing surface water was studied. Globally distributed and bioaccumulative PFOA does not absorb solar radiation by itself, but may be potentially photochemically transformed by the natural sensitizers such as dissolved organic matter (DOM), nitrate or ferric iron. Reaction solutions containing purified water, fulvic acid (representing DOM), nitrate, ferric iron or sea water from the Baltic Sea were spiked with PFOA and irradiated with an artificial sun (290-800 nm). In comparison similar samples were also irradiated under UV radiation at 254 nm in order to study the direct photolysis. UV radiation at 254 nm decomposed PFOA to perfluoroheptanoic-, perfluorohexanoic- and perfluoropentanoic acids. The samples irradiated with an artificial sun contained no decomposition products and no decrease in PFOA concentration was observed. According to the detection limit of the products and typical solar radiation at the surface of ocean, the photochemical half-life for PFOA was estimated to be at least 256 years at the depth of 0 m, >5000 years in the mixing layer of open ocean and >25,000 years in coastal ocean. This is significantly more than the previously reported photochemical half-life of PFOA (>0.96 years).
研究了全氟辛酸（PFOA）在代表地表水的条件下通过间接光解在水溶液中降解的潜力。全球分布且具有生物蓄积性的 PFOA 本身不吸收太阳辐射，但可能会被天然敏化剂（如溶解有机物（DOM）、硝酸盐或三价铁）潜在地光化学转化。在含有纯净水、富里酸（代表 DOM）、硝酸盐、三价铁或波罗的海海水的反应溶液中加入 PFOA 并用人工太阳（290-800nm）辐照。为了研究直接光解，还在 254nm 的紫外辐射下对类似的样品进行了辐照。254nm 的紫外辐射会将 PFOA 分解为全氟庚酸、全氟己酸和全氟戊酸。用人工太阳辐照的样品中没有分解产物，也没有观察到 PFOA 浓度的降低。根据产物的检测限和海洋表面典型的太阳辐射，估计 PFOA 的光化学半衰期在 0m 深度至少为 256 年，在开阔海洋的混合层中为 >5000 年，在沿海水域中为 >25000 年。这明显长于先前报道的 PFOA 光化学半衰期（>0.96 年）。
