Zimmerman John R, Ghosh Upal, Millward Rod N, Bridges Todd S, Luthy Richard G
Department of Civil and Environmental Engineering, Stanford University, Stanford, California 94305-4020, USA.
Environ Sci Technol. 2004 Oct 15;38(20):5458-64. doi: 10.1021/es034992v.
The addition of activated carbon as particulate sorbent to the biologically active layer of contaminated sediment is proposed as an in-situ treatment method to reduce the chemical and biological availability of hydrophobic organic contaminants (HOCs) such as polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). We report results from physicochemical experiments that assess this concept. PCB- and PAH-contaminated sediment from Hunters Point Naval Shipyard, San Francisco Bay, CA, was contacted with coke and activated carbon for periods of 1 and 6 months. Sediment treated with 3.4 wt % activated carbon showed 92% and 84% reductions in aqueous equilibrium PCB and PAH concentrations, 77% and 83% reductions in PCB and PAH uptake by semipermeable membrane devices (SPMD), respectively, and reductions in PCB flux to overlying water in quiescent systems up to 89%. Adding coke to contaminated sediment did not significantly decrease aqueous equilibrium PCB concentrations nor PCB or PAH availability in SPMD measurements. Coke decreased PAH aqueous equilibrium concentrations by 38-64% depending on coke dose and particle size. The greater effectiveness of activated carbon as compared to coke is attributed to its much greater specific surface area and a pore structure favorable for binding contaminants. The results from the physicochemical tests suggest that adding activated carbon to contaminated field sediment reduces HOC availability to the aqueous phase. The benefit is manifested relatively quickly under optimum contact conditions and improves in effectiveness with contact time from 1 to 6 months. Activated carbon application is a potentially attractive method for in-situ, nonremoval treatment of marine sediment contaminated with HOCs.
有人提出，在受污染沉积物的生物活性层中添加活性炭颗粒吸附剂，作为一种原位处理方法，以降低多氯联苯（PCBs）和多环芳烃（PAHs）等疏水性有机污染物（HOCs）的化学和生物有效性。我们报告了评估这一概念的物理化学实验结果。来自加利福尼亚州旧金山湾猎人角海军造船厂的受多氯联苯和多环芳烃污染的沉积物，与焦炭和活性炭接触了1个月和6个月。用3.4 wt%活性炭处理的沉积物，水相平衡中多氯联苯和多环芳烃浓度分别降低了92%和84%，半透膜装置（SPMD）对多氯联苯和多环芳烃的吸收分别降低了77%和83%，在静态系统中，多氯联苯向上覆水体的通量降低了89%。向受污染沉积物中添加焦炭，并没有显著降低水相平衡中的多氯联苯浓度，也没有降低半透膜装置测量中的多氯联苯或多环芳烃的有效性。根据焦炭剂量和粒径的不同，焦炭使多环芳烃水相平衡浓度降低了38%-64%。与焦炭相比，活性炭的效果更好，这归因于其更大的比表面积和有利于结合污染物的孔隙结构。物理化学测试结果表明，向受污染的现场沉积物中添加活性炭可降低疏水性有机污染物在水相中的有效性。在最佳接触条件下，这种益处相对较快地显现出来，并且随着接触时间从1个月增加到6个月，效果会有所改善。应用活性炭是一种对受疏水性有机污染物污染的海洋沉积物进行原位、非清除处理的潜在有吸引力的方法。
