Interdepartmental Graduate Program in Marine Science , University of California , Santa Barbara , California 93106 , United States.
Marine Science Institute , University of California , Santa Barbara , California 93106 , United States.
Environ Sci Technol. 2019 Mar 19;53(6):2971-2980. doi: 10.1021/acs.est.8b05859. Epub 2019 Mar 4.
Industrial-scale dumping of organic waste to the deep ocean was once common practice, leaving a legacy of chemical pollution for which a paucity of information exists. Using a nested approach with autonomous and remotely operated underwater vehicles, a dumpsite offshore California was surveyed and sampled. Discarded waste containers littered the site and structured the suboxic benthic environment. Dichlorodiphenyltrichloroethane (DDT) was reportedly dumped in the area, and sediment analysis revealed substantial variability in concentrations of p, p-DDT and its analogs, with a peak concentration of 257 μg g, ∼40 times greater than the highest level of surface sediment contamination at the nearby DDT Superfund site. The occurrence of a conspicuous hydrocarbon mixture suggests that multiple petroleum distillates, potentially used in DDT manufacture, contributed to the waste stream. Application of a two end-member mixing model with DDTs and polychlorinated biphenyls enabled source differentiation between shelf discharge versus containerized waste. Ocean dumping was found to be the major source of DDT to more than 3000 km of the region's deep seafloor. These results reveal that ocean dumping of containerized DDT waste was inherently sloppy, with the contents readily breaching containment and leading to regional scale contamination of the deep benthos.
工业规模地将有机废物倾倒入深海曾经是常见的做法，这给海洋带来了化学污染，而目前对此类污染的信息却十分匮乏。本研究采用嵌套式方法，使用自主式和遥控水下航行器对加利福尼亚近海的倾倒场进行了勘测和采样。废弃的废物容器遍布该区域，构成了缺氧海底环境的结构。据报道，滴滴涕曾在此区域倾倒，沉积物分析显示，p,p-DDT 及其类似物的浓度存在显著差异，其浓度峰值为 257μg/g，比附近滴滴涕超级基金场地的表层沉积物污染水平高出约 40 倍。一种明显的碳氢混合物的出现表明，多种石油馏分可能用于 DDT 的制造，从而导致了废物的产生。应用 DDT 和多氯联苯的两个端元混合模型进行源区分，表明与岸架排放相比，集装箱废物是 DDT 的主要来源。研究发现，海洋倾倒是该地区 3000 多公里深海海底 DDT 的主要来源。这些结果表明，集装箱 DDT 废物的海洋倾倒是草率的，其中的物质很容易突破容器的限制，导致深海底栖生物的区域污染。
