Neff Jerry M, Stout Scott A, Gunster Donald G
Battelle, 397 Washington Street, Duxbury, Massachusetts 02332, USA.
Integr Environ Assess Manag. 2005 Jan;1(1):22-33. doi: 10.1897/ieam_2004a-016.1.
Polycyclic aromatic hyftovst ond (PAH) are nearly ubiqutous contaminants of freshwater and marine sediments. Sediment PAHs are derived from combustion of organic matter, fossil fuels, and biosynthesis by microbes. Pyrogenic PAHs, particularly those associated with combustion particles (soot), have a low accessibility and bioavailability in sediments. Polycyclic aromatic hydrocarbons associated with petroleum, creosote, or coal tar in sediments may have a moderate accessibility/bioavailability, particularly if the PAHs are part of a nonaqueous phase liquid (NAPL) phase that is in contact with sediment pore water. We present a method for estimating the hazard of complex PAH assemblage in sediments to benthic organisms. Concentrations of all PAHs in sediment pore water are estimated by an equilibrium partitioning model relative to concentrations in bulk sediment. Predicted log Koc values can be used for predicting sediment/water partitioning of petrogenic PAH, but empirically derived log Kd values are needed to predict partitioning of pyrogenic PAH. A hazard quotient (HQ) for each PAH is calculated as the ratio of the estimated concentration in pore water to the chronic toxicity of the PAH determined by a log Kow/toxicity model. Hazard quotients for all PAH in a sample are summed to produce a hazard index (HI), which is a measure of the worst-case estimated hazard of the sediment PAH to benthic organisms. The results of this study show that the integration of HI results with PAH source data provides insights into the causes of sediment toxicity that are useful in an ecological risk assessment.
多环芳烃（PAH）几乎是淡水和海洋沉积物中普遍存在的污染物。沉积物中的PAH来源于有机物燃烧、化石燃料燃烧以及微生物的生物合成。热解PAH，尤其是那些与燃烧颗粒（烟灰）相关的PAH，在沉积物中的可及性和生物有效性较低。沉积物中与石油、杂酚油或煤焦油相关的多环芳烃可能具有中等的可及性/生物有效性，特别是如果PAH是与沉积物孔隙水接触的非水相液体（NAPL）相的一部分。我们提出了一种估算沉积物中复杂PAH组合对底栖生物危害的方法。通过相对于整体沉积物中浓度的平衡分配模型估算沉积物孔隙水中所有PAH的浓度。预测的log Koc值可用于预测成岩PAH的沉积物/水分配，但需要根据经验得出的log Kd值来预测热解PAH的分配。计算每个PAH的危害商（HQ），即孔隙水中估计浓度与通过log Kow/毒性模型确定的PAH慢性毒性的比值。将样品中所有PAH的危害商相加得出危害指数（HI），它是沉积物PAH对底栖生物最坏情况估计危害的一种度量。这项研究的结果表明，将HI结果与PAH源数据相结合，可为沉积物毒性的成因提供见解，这在生态风险评估中很有用。
