Characterization and Interpolation of Sediment PCBs and PBDEs in Resident Killer Whale Habitat along the Coast of British Columbia, Canada

• Main Author: Kim, Dr. Joseph
• Format: Text
• Language: English
• Published: Western CEDAR 2022
• Subjects: British Columbia; Canada; Pacific; Victoria Harbour; Killer Whale; Orca; Orcinus orca; Killer whale
• Online Access: https://cedar.wwu.edu/ssec/2022ssec/allsessions/21; https://cedar.wwu.edu/context/ssec/article/3183/viewcontent/22_f66a7162ff614c86856045fc77bbfc1a.pdf

Characterization and Interpolation of Sediment PCBs and PBDEs in Resident Killer Whale Habitat along the Coast of The northeastern Pacific Northern and Southern Resident Killer Whale (NRKW and SRKW) (Orcinus orca) populations are listed as threatened and endangered in Canada, respectively, with persistent, bioaccumulative contaminants, such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) posing threats to their recovery. Concentrations of PCBs and PBDEs in subtidal surface sediments collected from 97 sites along the British Columbia (BC) coast were used to identify their distribution and profiles, and to assess killer whale habitat quality. Victoria Harbour (VH3(site ID: 1)) sediments exhibited the highest 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 contaminant profiles, with PC1 for PCBs and PBDEs correlated with the octanol-water partition coefficient (LogKow; p < 0.003). Sediment particle size (SPS), total organic carbon (TOC), and water depth at collection were other factors associated with the distribution of PBDEs, while PCB profiles were associated with TOC. Total PCB and PBDE concentrations at 100% and 34% of the sites, respectively, exceeded the recently adopted British Columbia’s Ministry of Environment and Climate Change Strategy (BCMoE) Working Sediment Quality Guidelines (WSQGs) (PCBs: 3.7 pg/g dw and PBDEs: 1,000 pg/g dw), considered protective of killer whales. Our findings suggest that the legacy of banned PCBs and PBDEs is likely to constrain the recovery of killer whales as a result of their mobilization from sediments and consequent uptake by marine food webs.