Burgess R M, Ryba S A, Cantwell M G, Gundersen J L
US EPA, NHEERL, Atlantic Ecology Division Narragansett, Rhode Island 02882, USA.
Water Res. 2001 Dec;35(18):4390-404. doi: 10.1016/s0043-1354(01)00179-8.
The partitioning of nonpolar organic contaminants to marine sediments is considered to be controlled by the amount of organic carbon present. However, several studies propose that other characteristics of sediments may affect the partitioning of contaminants. For this exploratory analysis, we measured 19 sediment characteristics from five marine sediments and 11 characteristics of humic acids extracted from the sediments. These characteristics included elemental composition, grain size, soot carbon, polarity indices and molar ratios. Each individual characteristic and combinations of these characteristics were then used to normalize partition coefficients (Kp) generated for three organic contaminants: lindane, fluoranthene and a tetrachlorinated biphenyl (PCB). A coefficient of variation (CV) was then calculated for each contaminant to determine which normalization characteristic (individually or in combination) resulted in the lowest variability in partitioning between study sediments. For lindane and the PCB. normalization by the amount of sediment organic carbon resulted in the lowest variability in partition coefficients with CVs of 16.2% and 37.7%. respectively. However, normalization of fluoranthene by silt content resulted in lower CVs than those generated by organic carbon normalization: 31.0% vs. 37.6%. Normalization of contaminants Kp's by combined values of sediment characteristics resulted in lower CVs but only by a few percent. Using humic acid characteristics, humic organic carbon reduced variability between sediments most effectively. But only the normalized fluoranthene values had a CV (i.e., 25.4%) lower than the one based on normalization by sediment characteristics. When combined, humic acid characteristics resulted in lower CVs than normalization by individual or combinations of sediment characteristics for fluoranthene and the PCB with CVs of 19.3% and 28.7%, respectively. This analysis indicates variability associated with the partitioning of some organic contaminants to marine sediments can be further reduced when normalization by sediment characteristics other than organic carbon are utilized.
非极性有机污染物在海洋沉积物中的分配被认为受沉积物中有机碳含量的控制。然而，多项研究表明沉积物的其他特性可能会影响污染物的分配。在这项探索性分析中，我们测量了五种海洋沉积物的19种沉积物特性以及从这些沉积物中提取的腐殖酸的11种特性。这些特性包括元素组成、粒度、烟灰碳、极性指数和摩尔比。然后，将每种单独的特性以及这些特性的组合用于对三种有机污染物（林丹、荧蒽和一种四氯联苯（PCB））生成的分配系数（Kp）进行归一化。随后计算每种污染物的变异系数（CV），以确定哪种归一化特性（单独或组合）导致研究沉积物之间分配的变异性最低。对于林丹和多氯联苯，通过沉积物有机碳含量进行归一化导致分配系数的变异性最低，变异系数分别为16.2%和37.7%。然而，荧蒽通过粉砂含量进行归一化产生的变异系数低于通过有机碳归一化产生的变异系数：分别为31.0%和37.6%。通过沉积物特性的组合值对污染物的Kp进行归一化导致变异系数更低，但仅降低了几个百分点。使用腐殖酸特性，腐殖有机碳最有效地降低了沉积物之间的变异性。但只有归一化后的荧蒽值的变异系数（即25.4%）低于基于沉积物特性归一化的变异系数。当组合使用时，腐殖酸特性导致荧蒽和多氯联苯的变异系数低于通过单个或沉积物特性组合进行归一化的变异系数，分别为19.3%和28.7%。该分析表明，当利用有机碳以外的沉积物特性进行归一化时，一些有机污染物在海洋沉积物中分配的变异性可以进一步降低。
