Bioaccumulation of persistent organic pollutants in the deepest ocean fauna. Alan J. Jamieson, Tamas Malkocs, Stuart B. Piertney, Toyonobu Fujii & Zulin Zhang. Nature Ecology & Evolution 1, Article number: 0051 (2017) doi:10.1038/s41559-016-0051.

“…We measured the concentrations of key PCBs and PBDEs in multiple endemic and ecologically equivalent Lysianassoid amphipod Crustacea from across two of the deepest hadal trenches — the oligotrophic Mariana Trench in the North Pacific, and the more eutrophic Kermadec in the South Pacific. Two endemic amphipods (Hirondellea dubia and Bathycallisoma schellenbergi) were sampled from the Kermadec between 7,227 and 10,000 m, and one (Hirondellea gigas) from the Mariana between 7,841 and 10,250 m. Samples were obtained using traps deployed on deep-sea landers. The concentrations of seven PCB congeners identified by ICES for marine pollution assessment and seven PBDE congeners were measured both in sample dry weight (dw) and lipid weight (lw). The salient finding was that PCBs and PBDEs were present in all samples across all species at all depths in both trenches…” [emphasis added]