Polybrominated diphenylethers in the environment - Local and long range transport

Abstract: I have studied the sources, long range transport, and rates of flow of polybrominated diphenyl ethers (PBDEs), from the technosphere to the Baltic ecosystems. PBDEs are mainly used in polymers, which are applied in electrical equipment to prevent overheating or flashover and are produced in large quantities. PBDEs have become widely spread in the environment, where they are able to accumulate in biota (i.e. concentrations of PBDEs in human milk increase similar to that observed in wildlife) and induce toxic effects, such as thyroid disruption and neurological damage. To identify sources of PBDEs, air and precipitation were sampled at a municipal solid waste treatment plant (MSW) with an electronics recycling facility. Concentrations in both precipitation and air were higher at the MSW than at a reference station. Concentrations in air and rain at the reference station were depending on wind direction and higher levels were found when winds were blowing from the MSW area. It was concluded that treatment of waste and electronics recycling is presently a source of “old” PBDEs (Tetra-BDE47 and Penta-BDE99) to the environment, whereas Deca-BDE209 concentrations are more a result of proximity to potential diffuse sources. A negative relationship between the particulate PBDE concentration and rain volume was found, suggesting a dilution effect and indicating the importance of particle scavenging for wet deposition. To examine the distribution of PBDEs over Sweden, common frogs (Rana temporaria) were used as bioindicators. BDE47 was found in almost all frogs analysed, whereas BDE99 was detected in less than half of the frogs. PBDE concentrations were compared with that of PCBs. The fate of PCBs is well documented and believed to be similar to that of the PBDEs. I showed that PBDE and PCB concentrations in frogs were latitude related, supporting the global distillation theory. PBDE concentrations were significantly correlated with PCB concentrations, indicating similar contaminant sources and an analogous environmental fate. The PCB concentrations were one to two orders of magnitude higher than that of the PBDEs at southern latitudes, but the difference decreased to the north. To assess the long range transport and input of PBDEs to the Baltic Sea, air and atmospheric deposition were sampled on Gotska Sandön, situated in the central basin of the Baltic Sea. As predicted by their physicochemical properties, low brominated congeners were in the gas/dissolved phase, whereas higher brominated PBDEs were more in the particle phase, affecting their respective modes of transport. BDE209 was compared to PCBs and other PBDEs and shown to be the most dominant pollutant in the atmosphere of the Baltic Sea region. This could be attributed to DecaBDE's currently high consumption volume. I found that PBDE and PCB concentrations were highly correlated, indicating that their overall atmospheric transport is likely driven by the same mechanism. However, a difference was observed between the commercial DecaBDE formulation, BDE209 and the Penta-BDEs BDE47, 100, and 99. This suggested different underlying processes between "old" commercial PentaBDE and "new" DecaBDE formulations when transported over long distances through the atmosphere.