Graduate School of Oceanography, University of Rhode Island , Narragansett, Rhode Island 02882-1197, United States.
Environ Sci Technol. 2013 Sep 17;47(18):10429-37. doi: 10.1021/es402528q. Epub 2013 Sep 9.
Passive samplers can be useful tools for determining truly dissolved concentrations of organic contaminants in the water. Polyethylene (PE) samplers were validated for measuring polycyclic aromatic hydrocarbons (PAHs), with a focus on alkylated PAHs that can dominate in an oil spill. Equilibrium partition coefficients between water and PE passive samplers (KPEw) were measured for 41 PAHs both at ambient conditions (20 °C, no salt) and down to -15 °C with up to 245 psu present in ice brine. For each additional alkylated carbon, log KPEw increased by an average of 0.40 (±0.20) log units, close to predictions. The increase per aromatic carbon was only 0.33 (±0.02) log units. Apparent PE-water distributions of pyrene and deuterated pyrene (performance reference compound) were within 0.1 log unit for all experiments at 20 and 2 °C but started to diverge by 0.8 log units at -4 °C (100 psu) and by 3.1 log units at -15 °C (245 psu). The delay in equilibrating PAHs in these experiments was dominated by increases in the water viscosity, which, in turn, affected both the aqueous diffusivities of the PAHs and the thickness of the water boundary layer. In a simulated marine oil spill in the laboratory, PE-based results were within a factor of 2 of conventional sampling results for the most abundant PAHs.
被动采样器可以成为确定水中有机污染物真实溶解浓度的有用工具。聚乙烯（PE）采样器经过验证可用于测量多环芳烃（PAHs），重点是在溢油事件中占主导地位的烷基化 PAHs。在环境条件（20°C，无盐）和低至-15°C 下，用高达 245 psu 的冰盐水测量了 41 种 PAHs 与 PE 被动采样器之间的平衡分配系数（KPEw）。对于每个额外的烷基化碳原子，log KPEw 平均增加 0.40（±0.20）个对数单位，接近预测值。每个芳碳原子的增加仅为 0.33（±0.02）个对数单位。在 20°C 和 2°C 下，所有实验中苝和氘代苝（性能参考化合物）的表观 PE-水分配系数都在 0.1 对数单位内，但在-4°C（100 psu）时开始偏离 0.8 对数单位，在-15°C（245 psu）时偏离 3.1 对数单位。这些实验中 PAHs 平衡滞后的主要原因是水粘度的增加，这反过来又影响了 PAHs 的水扩散系数和水边界层的厚度。在实验室模拟海洋溢油事件中，基于 PE 的结果与最丰富的 PAHs 的常规采样结果相差约 2 倍。
