Sigleo A C, Means J C
U.S. Geological Survey, Lakewood, Colorado 80225.
Rev Environ Contam Toxicol. 1990;112:123-47. doi: 10.1007/978-1-4612-3342-8_3.
In colloids isolated from Chesapeake Bay and its subestuaries the concentrations of Al, Fe, and a number of trace elements were determined to vary with the clay mineral fraction that was most abundant in freshwater samples collected during the winter. The elements As, Ba, Sb, and Zn, however, increased with increasing organic content, indicating a covariance with the organic component. Organic analyses for amino acids (proteins), carbohydrates, and lipids indicate that these biopolymers comprised 4 to 22%, 20 to 60%, and less than 1%, respectively, of the colloidal organic carbon in these samples. The results are significant because amino acids and carbohydrates contain oxygen, nitrogen, and sulfur functional groups capable of reacting with trace metals and organic pollutants. The sorption properties of several neutral hydrophobic organic compounds, including PAHs and herbicides, and several aromatic amines were investigated using the estuarine colloidal material. The effects of several environmental variables on these sorption properties were determined. The results indicate that colloids have the capacity to sorb and transport relatively insoluble pollutants that otherwise might remain immobile in the environment. Colloidal organic matter in natural water systems (lakes, rivers, estuaries and the oceans, as well as groundwater) may serve as substrates for the sorption or binding of organic contaminants. Although most of the data has been developed using neutral hydrophobic organic compounds, data also exist for selected polar compound groups such as aromatic amines. The chemical behavior of these compound groups in interaction with DOM appears to have some similarity to their chemical interaction with sediments and soils. Partitioning constants are linear, except for polar compounds, and appear to be closely correlated to fundamental compound properties such as solubilities and octanol-water partition coefficients. Even though a variety of methods were used to collect the colloids for study and to determine partition coefficients, no single method appears to be superior. Ultrafiltration techniques appear to be optimal for collecting the colloids, since this method subjects the materials to less extreme chemical conditions than the preparation of humic extracts, whereas equilibrium techniques such as dialysis and head space analysis appear to yield the best results for partitioning constants. However, each of these techniques has limitations with respect to the classes of compounds that can be studied successfully.
在从切萨皮克湾及其河口分离出的胶体中，铝、铁和一些微量元素的浓度被测定为随冬季采集的淡水样本中最丰富的粘土矿物部分而变化。然而，砷、钡、锑和锌等元素随着有机含量的增加而增加，表明与有机成分存在协变关系。对氨基酸（蛋白质）、碳水化合物和脂质的有机分析表明，这些生物聚合物分别占这些样本中胶体有机碳的4%至22%、20%至60%和不到1%。这些结果很重要，因为氨基酸和碳水化合物含有能够与微量金属和有机污染物发生反应的氧、氮和硫官能团。使用河口胶体材料研究了几种中性疏水性有机化合物（包括多环芳烃和除草剂）以及几种芳香胺的吸附特性。确定了几个环境变量对这些吸附特性的影响。结果表明，胶体有能力吸附和运输相对不溶性的污染物，否则这些污染物可能会在环境中保持不动。天然水系统（湖泊、河流、河口和海洋以及地下水）中的胶体有机物可能作为有机污染物吸附或结合的底物。虽然大多数数据是使用中性疏水性有机化合物得出的，但也存在针对选定极性化合物组（如芳香胺）的数据。这些化合物组与溶解性有机质相互作用时的化学行为似乎与它们与沉积物和土壤的化学相互作用有一些相似之处。除了极性化合物外，分配常数是线性的，并且似乎与基本化合物性质（如溶解度和正辛醇 - 水分配系数）密切相关。尽管使用了多种方法来收集用于研究的胶体并确定分配系数，但似乎没有一种方法是 superior 的。超滤技术似乎是收集胶体的最佳方法，因为这种方法使材料受到的化学条件比腐殖质提取物的制备要温和，而诸如透析和顶空分析等平衡技术似乎能得出关于分配常数的最佳结果。然而，这些技术中的每一种在可成功研究的化合物类别方面都有局限性。
