Department of Civil and Environmental Engineering, Northeastern University, 400 Snell Engineering Center 360 Huntington Avenue, Boston, MA 02115, United States.
Sci Total Environ. 2012 Apr 15;423:168-75. doi: 10.1016/j.scitotenv.2012.01.042. Epub 2012 Mar 2.
Sediment remediation techniques to limit the bioavailability of contaminants are of special interest due to related acute or chronic toxicities associated with sediment contaminants. Bioavailability in aquatic sediments can be particularly problematic due to their accessibility to food chain biota, and interactions with surface and ground water. The effect of a reactive core mat (RCM) containing organoclay on the bioavailability of hydrophobic organic compounds (HOCs) (i.e., PCBs and naphthalene) was studied using oligochaete worms (Lumbriculus variegatus). Sediment sampled from the Neponset River (Milton, MA) with 10 ppm background PCB contamination was used in the experimental study. The objective of this study is to investigate the difference in HOC concentration of worms exposed to: a) a grab sample of contaminated sediment (10.4% total organic carbon); and b) an initially clean mixture of sand and organic matter (the so-called biouptake layer), placed on top of the RCM-capped sediment during consolidation coupled solute transport experiments. In addition to the experimental data, the U.S. Army Corps of Engineers (USACE) biota-sediment accumulation factor (BSAF) database was validated and used to model biouptake of contaminants for certain cases. Results indicate that RCM capping reduced the average bioavailability of both PCBs and naphthalene by a factor of about 50. In fact, worms exposed to the RCM-protected biouptake layer show virtually the same HOC concentrations as those measured in the control worm samples.
由于与沉积物污染物有关的急性或慢性毒性，限制污染物生物可利用性的沉积物修复技术引起了特别关注。由于水生沉积物易于被食物链生物利用，并且与地表水和地下水相互作用，因此其生物可利用性可能是一个特别棘手的问题。本研究使用寡毛类蠕虫（Lumbriculus variegatus）研究了含有有机粘土的反应性核心垫（RCM）对疏水性有机化合物（HOC）（即 PCB 和萘）生物可利用性的影响。实验研究中使用了从 Neponset 河（马萨诸塞州 Milton）采集的沉积物样品，其背景 PCB 污染为 10 ppm。本研究的目的是研究暴露于以下两种情况的蠕虫中 HOC 浓度的差异：a）受污染沉积物的抓取样品（总有机碳含量为 10.4%）；b）最初是干净的沙和有机物混合物（所谓的生物吸收层），在固结过程中放置在 RCM 覆盖的沉积物顶部，同时进行溶质传输实验。除了实验数据外，还验证并使用美国陆军工程兵团（USACE）生物-沉积物积累因子（BSAF）数据库来模拟某些情况下污染物的生物吸收。结果表明，RCM 覆盖层将两种 PCB 和萘的平均生物可利用性降低了约 50 倍。实际上，暴露于 RCM 保护的生物吸收层的蠕虫显示出与对照蠕虫样品中测量的 HOC 浓度几乎相同的 HOC 浓度。
