Characterization and Interpolation of Sediment Polychlorinated Biphenyls and Polybrominated Diphenyl Ethers in Resident Killer Whale Habitat along the Coast of British Columbia, Canada

摘要

The northeastern Pacific northern and southern resident killer whale (Orcinus orca) populations are listed asthreatened and endangered in Canada, respectively, with persistent, bioaccumulative contaminants, such as polychlorinatedbiphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), posing threats to their recovery. Concentrations of PCBs andPBDEs in subtidal surface sediments collected from 97 sites along the British Columbia (BC) coast were used to identify theirdistribution and profiles, and to assess killer whale habitat quality. Victoria Harbour (VH3(site ID: 1)) sediments exhibited thehighest PCB and PBDE concentrations. For PCBs, PCB‐138 was found at the highest concentration, followed by PCB‐153,PCB‐110, PCB‐149, PCB‐101, and PCB‐118. For PBDEs, individual congeners were ranked as follows: BDE‐209 > BDE‐207 > BDE‐206 > BDE‐208 > BDE‐47 > BDE‐99. Principal component analyses (PCA) illustrated the variations in contaminantprofiles, with PC1 for PCBs and PBDEs correlated with the octanol‐water partition coefficient (log KOW, p < 0.003). Based onthe PCA, sediment particle size, total organic carbon (TOC), and water depth at collection were other factors associated withthe distribution of PBDEs, while PCB profiles were associated with TOC. Total PCB and PBDE concentrations at 100 and34 of the sites, respectively, exceeded the recently adopted British Columbia's Ministry of Environment and ClimateChange Strategy Working Sediment Quality Guidelines (PCBs 3.7 pg/g dry wt and PBDEs 1000 pg/g dry wt), consideredprotective of killer whales. Our findings suggest that the legacy of banned PCBs and PBDEs has the potential to constrain therecovery of killer whales as a result of their mobilization from sediments and consequent uptake by marine food webs.