Department of Environmental Sciences, University of California, Riverside, California 92521, United States.
College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
Environ Sci Technol. 2023 Jun 27;57(25):9385-9393. doi: 10.1021/acs.est.3c02309. Epub 2023 Jun 15.
Carbonaceous materials are often proposed for use in restoring soils or sediments contaminated with hydrophobic organic contaminants (HOCs). However, the contamination of most sites is a result of historical events, where HOCs have resided in the solid compartment for many years or decades. The prolonged contact time, or aging, leads to reduced contaminant availability and likely diminished effectiveness of using sorbents. In this study, three different carbonaceous sorbents, i.e., biochars, powdered activated carbon, and granular activated carbon, were amended to a Superfund site marine sediment contaminated with DDT residues from decades ago. The amended sediments were incubated in seawater for up to 1 year, and the freely dissolved concentration () and the biota-sediment accumulation factors (BSAFs) for a native polychaete () were measured. Even though the bulk sediment concentrations were very high (6.4-154.9 μg/g OC), both and BSAFs were very small, ranging from nd to 1.34 ng/L and from nd to 0.024, respectively. The addition of carbonaceous sorbents, even at 2% (w/w), did not consistently lead to reduced DDT bioaccumulation. The limited effectiveness of carbonaceous sorbents was attributed to the low DDT availability due to prolonged aging, highlighting the need for considering contaminant aging when using sorbents for remediation.
碳质材料通常被提议用于修复受疏水性有机污染物（HOCs）污染的土壤或沉积物。然而，大多数污染场地的污染是历史事件的结果，其中 HOCs 在固体相中长期存在了多年或几十年。长时间的接触，或老化，导致污染物的可用性降低，使用吸附剂的效果可能减弱。在这项研究中，三种不同的碳质吸附剂，即生物炭、粉末状活性炭和颗粒状活性炭，被添加到一个超级基金场地的海洋沉积物中，该沉积物受到几十年前滴滴涕残留的污染。添加了吸附剂的沉积物在海水中孵育长达 1 年，并测量了自由溶解浓度（）和本土多毛类动物（）的生物沉积物积累因子（BSAFs）。尽管大部分沉积物浓度非常高（6.4-154.9 μg/g OC），但和 BSAFs 都非常小，范围分别从 nd 到 1.34ng/L 和 nd 到 0.024。即使添加了 2%（w/w）的碳质吸附剂，也不能始终降低滴滴涕的生物积累。碳质吸附剂的有限效果归因于由于长时间的老化导致滴滴涕的可用性降低，这突出表明在使用吸附剂进行修复时需要考虑污染物的老化。
