Department of Environmental Technology, Norwegian Geotechnical Institute, 0806 Oslo, Norway.
Environ Sci Technol. 2011 May 1;45(9):4053-9. doi: 10.1021/es200174v. Epub 2011 Apr 7.
Vertical pore water profiles of in situ PCBs were determined in a contaminated mudflat in San Francisco Bay, CA, 30 months after treatment using an activated carbon amendment in the upper layer of the sediment. Pore water concentrations were derived from concentrations of PCBs measured in two passive samplers; polyethylene (PE, 51 μm thick) and polyoxymethylene (POM, 17 μm thick) at different sediment depths. To calculate pore water concentrations from PCB contents in the passive samplers, an equilibrium approach and a first-order uptake model were applied, using five performance reference compounds to estimate pore water sampling rates. Vertical pore water profiles showed good agreement among the measurement and calculation methods with variations within a factor of 2, which seems reasonable for in situ measurements. The close agreements of pore water estimates for the two sampler materials (PE and POM) and the two methods used to translate uptake in samplers to pore water concentrations demonstrate the robustness and suitability of the passive sampling approach. The application of passive samplers in the sediment presents a promising method for site monitoring and remedial treatment evaluation of sorbent amendment or capping techniques that result in changes of pore water concentrations in the sediment subsurface.
在加利福尼亚州旧金山湾的一个受污染的泥滩中，在使用上层沉积物中的活性炭添加剂进行原位 PCB 处理 30 个月后，确定了原位 PCBs 的垂直孔隙水分布。孔隙水浓度是从两种被动采样器（厚度分别为 51μm 的聚乙烯（PE）和 17μm 的聚甲醛（POM））在不同沉积物深度处测量的 PCB 浓度中得出的。为了从被动采样器中的 PCB 含量计算孔隙水浓度，应用了平衡方法和一级吸收模型，并使用了五种性能参考化合物来估算孔隙水采样速率。垂直孔隙水分布与测量和计算方法之间具有良好的一致性，变化幅度在 2 倍以内，这对于原位测量来说似乎是合理的。两种采样器材料（PE 和 POM）和两种用于将采样器中的吸收转化为孔隙水浓度的方法得出的孔隙水估算值之间的密切一致性，证明了被动采样方法的稳健性和适用性。被动采样器在沉积物中的应用为监测和评估受溶质添加剂或覆盖技术影响的场地提供了一种很有前途的方法，这些技术会导致沉积物亚表面孔隙水浓度发生变化。
