Environmental fractionation of PCBs and PBDEs during particle transport as recorded by sediments in coastal waters

Abstract

The Strait of Georgia (British Columbia, Canada) is a hydrologically complex inland sea with a rich abundance and diversity of species of aquatic life. Marine sediments, as both a sink for hydrophobic contaminants and a potential source for aquatic food webs, were collected from 41 sites throughout the 6,900-km(2) Strait of Georgia. The congener-specific concentrations of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), including BDE-209, were measured. Urban harbors represented hotspots for both PCBs and PBDEs, whereas PBDEs were also found at high concentrations near municipal outfalls. Patterns of PCB distribution were consistent with historical point source emissions in urban areas and environmental distillation toward lighter profiles in remote sites over time. The single congener BDE-209 dominated the PBDEs, accounting for 52% of the average total concentration. However, nonurban deep-water sediment PBDE profiles were both heavier and had higher concentration-weighted average log K(OW) (octanol-water partition coefficient) values compared to shallow samples (percent BDE-209 of total PBDE, 66 versus 32%; log K(OW) , 9.5 versus 8.2, respectively). Collectively, our results suggest that although source signals largely explain PCB and PBDE hotspots in the Strait of Georgia, the combination of physicochemical properties and environmental processes drive divergent compositional fates for the PCBs and the heavier PBDEs in the sediments of the Strait of Georgia.

Effect of receiving environment on the transport and fate of polybrominated diphenyl ethers near two submarine municipal outfalls

“…Widely used as flame-retardants in furniture, fabrics, and electronics [11], PBDEs enter municipal wastewater streams through household ) [12] and are persistent, bioaccumulative, and toxic [8,11,13]. Previous work [10,14] compared the depositional histories of polychlorinated biphenyls and PBDEs in the Strait of Georgia and explained their distribution over a wide area in surface sediments.…”

Food Web Bioaccumulation Model for Resident Killer Whales from the Northeastern Pacific Ocean as a Tool for the Derivation of PBDE-Sediment Quality Guidelines

“…Within this context, it is important to capture the distribution of PBDE congeners in the environment in the model. Empirical studies have found a particular set of congeners in resident killer whale habitat and biota (Ikonomou et al 2002a;Ryane and Konomou 2002;Grant et al 2011;Alava et al 2012a, b;Frouin et al 2013); however, we have restricted those included in the model to the ones with the most PBDE congeners' data in the areas of interest (Table S3). Once the model has calculated concentrations of all PBDE congeners included, a total PBDE (RPBDE) concentration was calculated as the sum of the concentrations of the congeners included in the model.…”

“…This assumption is reasonable for several reasons. First, PBDE sediment concentrations' monitoring programs have included a significant distribution of PBDE sediment concentration hot spots throughout the Strait of Georgia (Grant et al 2011), as illustrated in Fig. S4.…”

“…This was based on sampling locations as shown in Fig. S3 and the availability of PBDE sediment concentration data reported for these sites (Table S1; Grant et al 2011). In addition, concentrations of PBDEs freely dissolved in water (Table S2) were retrieved from Frouin et al (2013) and used as input data in the model.…”

“…Even though some PBDE formulations have been banned or are no longer used in Canada, they are persistent and are transported atmospherically from areas that continue to use them and cycling has produced stable concentrations in the environmental compartments (Johannessen et al 2008;Ross et al 2009;Noël et al 2009;Grant et al 2011;Frouin et al 2013). As with PCBs, PBDEs can enter killer whale habitat in a variety of ways: atmospheric deposition, urban runoff, sewage outfalls, ground water, watersheds such as the Fraser River, and smaller tributaries.…”