Department of Environmental Engineering, Norwegian Geotechnical Institute, Oslo, Norway.
Environ Toxicol Chem. 2011 Apr;30(4):843-51. doi: 10.1002/etc.466. Epub 2011 Feb 8.
Contaminant levels in urban harbor sediments vary with contaminant emission levels, sedimentation rates, and sediment resuspension processes such as propeller wash. Levels of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) are decreasing in many urban harbors, as heavily contaminated sediments that accumulated during past decades are being buried by less-contaminated sediments. However, PAHs and PCBs remain a concern in areas where burial is slow or resuspension processes re-expose heavily contaminated older layers. Chronostratigraphic sediment core studies typically characterize contaminant level histories by using total sediment concentrations, C(sed) , and do not determine the freely dissolved porewater concentrations, C(pw) , which provide a better measure of bioavailability. Here both C(sed) and C(pw) profiles were established for PAHs and PCBs in dated sediment cores from diverse areas of Oslo Harbor, Norway. Sediment-porewater partitioning profiles were established alongside profiles of various sorbing carbonaceous phases, including total organic carbon (TOC), black carbon, and diverse carbonaceous geosorbents identified by petrographic analysis. Stratigraphic trends in carbonaceous phases and C(sed) could be associated with different industrial epochs: hydropower (post-1960, approximately), manufactured gas (∼1925-1960), coal (∼1910-1925), and early industry (∼1860-1910). Partitioning was highly variable and correlated best with the TOC. Hydropower-epoch sediments exhibit decreasing C(sed) with time and a relatively strong sorption capacity compared with the manufactured-gas epoch. Sediments from the manufactured-gas epoch exhibit substantial PAH and metal contamination, large amounts of coke and char, and a low sorption capacity. Reexposure of sediments of this epoch increases risks to local benthic species. Implications on natural recovery as a sediment management strategy are discussed.
城市港口沉积物中的污染物水平随污染物排放水平、沉积速率以及螺旋桨冲刷等沉积物再悬浮过程而变化。在许多城市港口，多环芳烃 (PAHs) 和多氯联苯 (PCBs) 的水平正在下降，因为过去几十年积累的污染严重的沉积物正在被污染程度较低的沉积物掩埋。然而，在那些掩埋速度较慢或再悬浮过程使污染严重的旧层重新暴露的地区，PAHs 和 PCBs 仍然是一个问题。 年代地层学沉积物岩芯研究通常通过使用总沉积物浓度 C(sed) 来描述污染物水平历史，而不测定自由溶解的孔隙水浓度 C(pw)，后者提供了更好的生物利用度衡量标准。在这里，对来自挪威奥斯陆港不同地区的经过年代标定的沉积物岩芯中的 PAHs 和 PCBs 建立了 C(sed) 和 C(pw) 剖面。建立了沉积物-孔隙水分配剖面，同时还建立了各种吸附碳质相（包括总有机碳 (TOC)、黑碳和通过岩相分析确定的各种碳质地质吸附剂）的剖面。碳质相和 C(sed) 的地层趋势可与不同的工业时代相关联：水电（1960 年后，大约）、人造气（约 1925-1960 年）、煤炭（约 1910-1925 年）和早期工业（约 1860-1910 年）。分配高度可变，与 TOC 相关性最好。水电时代的沉积物随时间推移表现出 C(sed) 的减少，与人造气时代相比具有较强的吸附能力。人造气时代的沉积物显示出大量的 PAH 和金属污染、大量的焦炭和炭黑，以及较低的吸附能力。该时代沉积物的重新暴露增加了对当地底栖物种的风险。讨论了作为沉积物管理策略的自然恢复的影响。
