Department of Ocean Engineering and Marine Sciences, Florida Institute of Technology, Melbourne, Florida, USA.
Neff & Associates, Hendersonville, North Carolina, USA.
Integr Environ Assess Manag. 2019 Mar;15(2):209-223. doi: 10.1002/ieam.4069. Epub 2018 Aug 10.
Impacts from oil exploration, development, and production in the Beaufort Sea, Alaska, USA are assessed using concentrations of metals in sediments collected during 2014 to 2015, combined with a large data set for 1985 to 2006. Concentrations of 7 (1980s) or 17 (1999-2015) metals in 423 surface sediments from 134 stations, plus 563 samples from 30 cores were highly variable, primarily as a function of sediment granulometry with naturally greater metals concentrations in fine-grained, Al-rich sediment. Metals versus Al correlation plots were used to normalize metals concentrations and identify values significantly above background. Barium, Cr, Cu, Hg, and Pb concentrations were above background, but variable, within 250 m of some offshore sites where drilling occurred between 1981 and 2001; these areas totaled <6 km of 11 000 km in the total lease area. Random and fixed sampling along the coastal Beaufort Sea from 1985 to 2015 yielded 40 positive anomalies for metals in surface sediments (∼0.8% of 5082 data points). About 85% of the anomalies were from developed areas. Half the anomalies were for the 5 metals found enhanced near drilling sites. No metals concentrations, except As, exceeded accepted sediment quality criteria. Interannual shifts in metals values for surface sediments at inner shelf sites were common and linked to storm-induced transitions in granulometry; however, metal-to-Al ratios were uniform during these shifts. Sediment cores generally recorded centuries of background values, except for As, Fe, and Mn. These 3 metals were naturally enriched in sediments from deeper water (>100 m) via diagenetic remobilization at sediment depths of 5 to 15 cm, upward diffusion, and precipitation in surface oxic layers. Minimal evidence for anthropogenic inputs of metals, except near some exploratory drilling sites, is consistent with extraction of most oil from land or barrier islands in the Alaskan Arctic and restricted offshore activity to date. Integr Environ Assess Manag 2019;15:209-223. © 2018 SETAC.
使用 2014 年至 2015 年期间采集的沉积物中金属浓度评估了美国阿拉斯加波弗特海的石油勘探、开发和生产的影响，同时还结合了 1985 年至 2006 年的大量数据集。在 134 个站位的 423 个表层沉积物中，7 种（1980 年代）或 17 种（1999-2015 年）金属的浓度变化很大，主要与沉积物粒度有关，富含 Al 的细粒沉积物中金属浓度自然较高。金属与 Al 的相关图用于归一化金属浓度并识别出明显高于背景的浓度值。在 1981 年至 2001 年期间进行钻探的一些近海地点附近 250 m 范围内，钡、Cr、Cu、Hg 和 Pb 的浓度高于背景值，但变化较大；这些区域在总租约面积 11000 公里中总计不到 6 公里。1985 年至 2015 年沿波弗特海沿海地区进行的随机和固定采样在表层沉积物中产生了 40 个金属异常（约占 5082 个数据点的 0.8%）。大约 85%的异常来自已开发区域。一半的异常是在钻井点附近发现的 5 种金属增强的异常。除了 As 之外，没有金属浓度超过公认的沉积物质量标准。内陆架站点表层沉积物中金属值的年际变化很常见，与风暴引起的粒度变化有关；然而，在这些变化过程中，金属与 Al 的比值是一致的。除了 As、Fe 和 Mn 之外，沉积物芯通常记录了数百年的背景值。这 3 种金属通过在 5 至 15 cm 的沉积物深度处的成岩再迁移、向上扩散以及在表层氧化层中的沉淀，在更深的水（>100 m）中自然富集在沉积物中。除了一些勘探性钻井点附近，除了一些勘探性钻井点附近，没有发现金属人为输入的证据，这与大多数石油从阿拉斯加北极的陆地或障壁岛开采以及迄今为止限制近海活动是一致的。2019 年《综合环境评估与管理》209-223 页。©2018 SETAC。
