The persistent DDT footprint of ocean disposal, and ecological controls on bioaccumulation in fishes

• 成果类型: Article
• 署名作者: McGill, Lillian; Sleugh, Toni; Petrik, Colleen; Schiff, Kenneth; McLaughlin, Karen; Aluwihare, Lihini; Semmens, Brice
• 署名单位: University of California System; University of California San Diego; Scripps Institution of Oceanography; University of California System; University of California San Diego; Scripps Institution of Oceanography; Southern California Coastal Water Research Project; University of California System; University of California San Diego; Scripps Institution of Oceanography
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-13202
• DOI: 10.1073/pnas.2401500121
• 发表日期: 2024-11-05
• 关键词: southern california bight; trophic magnification factors; pelagic food webs; los-angeles; organochlorine contaminants; polychlorinated-biphenyls; biomagnification; sediments; MODEL; lake

摘要

Globally, ocean dumping of chemical waste is a common method of disposal and relies on the assumption that dilution, diffusion, and dispersion at ocean scales will mitigate human exposure and ecosystem impacts. In southern California, extensive dumping of agrochemical waste, particularly chlorinated hydrocarbon contaminants such as DDT, via sewage outfalls and permitted offshore barging occurred for most of the last century. This study compiled a database of existing sediment and fish DDT measurements to examine how this unique legacy of regional ocean disposal translates into the contemporary contamination of the coastal ocean. We used spatiotemporal modeling to derive continuous estimates of sediment DDT contamination and show that the spatial signature of disposal (i.e., high loadings near historic dumping sites) is highly conserved in sediments. Moreover, we demonstrate that the proximity of fish to areas of high sediment loadings explained over half of the variation in fish DDT concentrations. The relationship between sediment and fish contamination was mediated by ecological predictors (e.g., species, trophic ecology, habitat use), and the relative influence of each predictor was context- dependent, with habitat exhibiting greater importance in heavily contaminated areas. Thus, despite more than half a century since the cessation of industrial dumping in the region, local ecosystem contamination continues to mirror the spatial legacy of dumping, suggesting that sediment can serve as a robust predictor of fish contamination, and general ecological characteristics offer a predictive framework for unmeasured species or locations.