Spongberg Alison L
Department of Earth, Ecological and Environmental Sciences, M.S. 604, University of Toledo, Toledo, Ohio 43606-3390, USA.
Rev Biol Trop. 2004 Dec;52 Suppl 2:23-32.
Twenty-nine marine sediment samples collected from 1996 through 2002 from the Golfo Dulce embayment of Costa Rica were analyzed for PCB concentrations. The Esquinas River and Rincon Bay in the northern and western part of the gulf had relatively low overall concentrations of PCBs, with no samples having greater than 2.1 microg/g dw sediment. The Port of Golfito had the highest overall concentrations, ranging up to 15.7 microg/g dw sediment. These samples were also dominated by higher chlorinated congeners. Samples from the deeper (> 100 m) waters in the northern part of the gulf, as well as within the sediment plume from the Rio Coto Colorado had intermediate values. Within the Rio Coto Colorado sediment plume the concentrations did decrease with increasing depth and the congeners showed a shift towards less chlorinated congeners with depth. However, the deep northern basin had some of the highest PCB concentrations and the shift towards less chlorinated congeners was not apparent or significant. Whether the anoxic conditions that exist in the deep waters are capable of initiating dechlorination is still unknown. Overall, the data from Golfo Dulce show moderate PCB contamination, despite the pristine nature of the gulf and surrounding lands.
对1996年至2002年期间从哥斯达黎加杜尔塞湾采集的29个海洋沉积物样本进行了多氯联苯浓度分析。海湾北部和西部的埃斯基纳斯河和林孔湾的多氯联苯总体浓度相对较低，没有样本的沉积物干重中多氯联苯含量超过2.1微克/克。戈尔菲托港的总体浓度最高，沉积物干重中多氯联苯含量高达15.7微克/克。这些样本也以高氯代同系物为主。海湾北部较深（>100米）水域以及科托科罗拉多河沉积物羽流内的样本浓度处于中间值。在科托科罗拉多河沉积物羽流内，浓度确实随深度增加而降低，并且同系物随深度显示出向氯代程度较低的同系物转变。然而，北部深海盆地的多氯联苯浓度是最高的一些，向氯代程度较低的同系物的转变并不明显或显著。深水中存在的缺氧条件是否能够引发脱氯作用仍然未知。总体而言，尽管杜尔塞湾及其周边陆地具有原始特性，但来自杜尔塞湾的数据显示多氯联苯受到了中度污染。
