Marie Noel
PCBs are transported through the atmosphere in both gas and particulate phases. In Great Lakes and Baltic Sea, the majority of aquatic PCBs come from atmospheric transport. Transport from Asia to BC takes 2-10 days. One sampling site at Ucluelet as reference for Saturna Island samples (gas (86% of PCBs, 63% PBDEs), particulate (porportionally more heavy congeners), and rain phases). PCB heavy congeners dominated by tri and tetra; PBDEs by tetra, penta and deca.
PBDE deposition was higher than PCBs overall. PCBs about same between sites, suggesting global sources. ~50% of PBDEs are coming from local sources, and the increase above reference is mostly due to heavier PBDEs (tetra, penta, deca). The point of origin is 20% from Asia; no north American sources can account for the coastal deposition in BC.
2004 deposition mass: 3.5 kg PCB, 20 kg PBDE (BDE 209 makes of 56%)