Santschi P H, Presley B J, Wade T L, Garcia-Romero B, Baskaran M
Texas A&M University, Department of Oceanography, Galveston 77551, USA.
Mar Environ Res. 2001 Jul;52(1):51-79. doi: 10.1016/s0141-1136(00)00260-9.
Profiles of trace contaminant concentrations in sediment columns can be a natural archive from which pollutant inputs into coastal areas can be reconstructed. Reconstruction of historical inputs of anthropogenic chemicals is important for improving management strategies and evaluating the success of recent pollution controls measures. Here we report a reconstruction of historical contamination into three coastal sites along the US Gulf Coast: Mississippi River Delta, Galveston Bay and Tampa Bay. Within the watersheds of these areas are extensive agricultural lands as well as more than 50% of the chemical and refinery capacity of the USA. Despite this pollution potential, relatively low concentrations of trace metals and trace organic contaminants were found in one core from each of the three sites. Concentrations and fluxes of most trace metals found in surface sediments at these three sites, when normalized to Al, are typical for uncontaminated Gulf Coast sediments. Hydrophobic trace organic contaminants that are anthropogenic (polycyclic aromatic hydrocarbons, DDTs, and polychlorinated biphenyls) are found in sediments from all locations. The presence in surface sediments from the Mississippi River Delta of low level trace contaminants such as DDTs, which were banned in the early 1970's, indicate that they are still washed out from cultivated soils. It appears that the DDTs profile in that sediment core was produced by a combination of erosion processes of riverine and other sedimentary deposits during floods. Most of the pollutant profiles indicate that present-day conditions have improved from the more contaminated conditions in the 1950-1970's, before the advent of the Clean Water Act.
沉积物柱中痕量污染物浓度的分布情况可成为一个天然档案库，从中能够重建进入沿海地区的污染物输入情况。重建人为化学物质的历史输入情况对于改进管理策略以及评估近期污染控制措施的成效而言至关重要。在此，我们报告了对美国墨西哥湾沿岸三个沿海地点（密西西比河三角洲、加尔维斯顿湾和坦帕湾）历史污染情况的重建。在这些地区的流域内有广袤的农田，以及美国超过50%的化工和炼油产能。尽管存在这种污染潜力，但在这三个地点的每个地点的一个岩芯中发现痕量金属和痕量有机污染物的浓度相对较低。这三个地点表层沉积物中发现的大多数痕量金属的浓度和通量，经铝归一化后，是未受污染的墨西哥湾沿岸沉积物的典型特征。在所有地点的沉积物中都发现了人为来源的疏水性痕量有机污染物（多环芳烃、滴滴涕和多氯联苯）。在密西西比河三角洲表层沉积物中存在诸如滴滴涕这类在20世纪70年代初就已被禁止使用的低水平痕量污染物，这表明它们仍在从耕地中被冲刷出来。看来该沉积物岩芯中的滴滴涕分布情况是由洪水期间河流和其他沉积矿床的侵蚀过程共同造成的。大多数污染物分布情况表明，自《清洁水法》出台之前的20世纪50 - 70年代污染更严重的状况以来，如今的情况已有所改善。
