National Wildlife Research Centre, Science and Technology Branch, Environment Canada, Carleton University, Ottawa, ON, K1A 0H3, Canada.
Environ Sci Technol. 2010 May 15;44(10):3739-45. doi: 10.1021/es100474r.
Linear and branched (six mono(trifluoromethyl) and four di(trifluoromethyl)) isomers of the bioaccumulative contaminant perfluorooctane sulfonate (PFOS) were analyzed for and the spatial patterns examined in individual herring gull (Larus argentatus) eggs (n = 13 per site) collected (in 2007) from 15 colonies across the Laurentian Great Lakes of North America. Linear PFOS (n-perfluoro-1-octanesulfonate (L-PFOS)) consistently dominated the isomer pattern in all eggs, comprising between 95.0% and 98.3% of the summation sigmaPFOS concentration. L-PFOS was highly enriched in the gull eggs as the summation sigmabranched-PFOS to L-PFOS isomer concentration ratios were very constant (overall average 0.038 +/- 0.001) and much lower compared to technical PFOS (range 0.27-0.54). The highest proportions of L-PFOS were generally observed in the eggs from the lower lakes (Erie and Ontario) colonies. All six mono(trifluoromethyl) branched isomers, or perfluoro-n-methyl-heptanesulfonates where n describes the carbon of the hydrocarbon chain were there is trifluoromethyl substitution relative to the sulfonate terminal group, were detected in the eggs from all the colonies. For example, P1MHpS is perfluoro-1-methyl-heptanesulfonate. Comparable to technical PFOS (T-PFOS), the percentage of the mono(trifluoromethyl) isomer to summation sigmaPFOS concentration decreased as the branch substitution was located closer to the sulfonate group, that is, P6MHpS (0%-2.5%), P5MHpS (0.43%-1.18%), P4MHpS (0.25%-0.69%), and P3MHpS (0.32%-0.74%). Although at even lower fractional composition than the mono(trifluoromethyl) isomers, of the di(trifluoromethyl) isomers, detected in >60% of the individual eggs per site was P35DMHxS and P45DMHxS for Toronto Harbour (Lake Ontario), P35DMHxS for Chantry (Lake Huron) and Fighting Island (Detroit River), and P45DMHxS for Gull Island (Lake Michigan). Relative to T-PFOS, and independent of colonial location, the high and consistent enrichment of L-PFOS in gull eggs is likely a function of several processes including PFOS or precursor sources, and isomer-specific PFOS or precursor exposure, accumulation, biotransformation, retention and/or elimination. The results of this study suggests that the apparent dilution of the mono(fluoromethyl) isomers from environmental processes that occur prior to final accumulation in herring gull eggs, is independent of the mono(fluoromethyl) isomer structure.
线性和支链（六单（三氟甲基）和四双（三氟甲基））同系物的生物蓄积性污染物全氟辛烷磺酸（PFOS）进行了分析，并研究了在从北美五大湖的 15 个殖民地收集的（2007 年）单个海鸥（Larus argentatus）卵（每个地点 13 个）中的空间模式。在所有卵中，线性 PFOS（n-全氟-1-辛烷磺酸盐（L-PFOS））始终占同系物模式的主导地位，占总 PFOS 浓度的 95.0％至 98.3％。L-PFOS 在海鸥卵中高度富集，因为支链 PFOS 与 L-PFOS 异构体浓度的比值非常恒定（总体平均值为 0.038±0.001），与技术 PFOS 相比要低得多（范围为 0.27-0.54）。通常，在来自较低湖泊（伊利湖和安大略湖）殖民地的卵中观察到最高比例的 L-PFOS。在所有殖民地的卵中均检测到所有六个单（三氟甲基）支链异构体，或全氟-n-甲基庚烷磺酸盐，其中 n 描述了相对于磺酸盐末端基团的烃链的碳原子，存在三氟甲基取代。例如，P1MHpS 是全氟-1-甲基庚烷磺酸盐。与技术 PFOS（T-PFOS）类似，单（三氟甲基）异构体与总 sigmaPFOS 浓度的百分比随着支链取代位置更接近磺酸盐基团而降低，即 P6MHpS（0％-2.5％），P5MHpS（0.43％-1.18％），P4MHpS（0.25％-0.69％）和 P3MHpS（0.32％-0.74％）。尽管单（三氟甲基）异构体的分数组成甚至更低，但在每个地点的个体卵中均检测到的双（三氟甲基）异构体中，有超过 60％的是多伦多港（安大略湖）的 P35DMHxS 和 P45DMHxS，安大略湖的 Chantry（Chantry）和底特律河的 Fighting Island（Fighting Island）的 P35DMHxS，以及密歇根湖的 Gull Island（Gull Island）的 P45DMHxS。相对于 T-PFOS，并且与殖民地位置无关，L-PFOS 在海鸥卵中的高度和一致富集可能是包括 PFOS 或前体来源以及异构体特异性 PFOS 或前体暴露，积累，生物转化，保留和/或消除在内的多种过程的结果。这项研究的结果表明，在最终在海鸥卵中积累之前，环境过程中对单（氟甲基）异构体的明显稀释与单（氟甲基）异构体的结构无关。
