Anna Palm

The environmental occurrence of hexabromocyclododecane in Sweden

The brominated flame retardant hexabromocyclododecane (HBCD) is extensively used in Europe, but data on the environmental concentrations of this chemical are scarce. A first screening has been performed concerning the environmental occurrence of HBCD in Sweden, a country where the chemical is not produced and the current industrial use is very limited. Possible emission sources were identified through a systematic analysis of the use in a life cycle perspective. In addition to a few point sources, diffuse emissions from polymeric products are possible. Measurements have been performed close to certain possible point sources, in the urban environment and in remote regions, and included air, deposition, water, soil, sediments, sludge, biota and foodstuffs. HBCD was detected in all media analysed and in all environments. The relatively high concentrations detected in herring and foodstuffs provide evidence for bioaccumulation of HBCD. The presence of HBCD in remote background air implies that HBCD has potential for long-range atmospheric transport. There are also some indications that diffuse emissions of HBCD occur in the urban environment.

Assessing the environmental fate of chemicals of emerging concern: a case study of the polybrominated diphenyl ethers

It is suggested that assessments of chemicals of emerging concern can be rationally structured around a multistage process in which fate and risk are evaluated with increasing accuracy as new data become available. An initial tentative and approximate assessment of fate and risk can identify key data gaps and justify and direct further investigations, which progressively improve the reliability of the assessment. This approach is demonstrated for a class of chemicals, the polybrominated diphenyl ethers (PBDEs), which is of increasing concern, but about which there is presently a lack of comprehensive data on properties, sources, fate and effects. Specifically, 20 PBDE congeners are investigated using the suggested approach and research needs are identified.

Physical-Chemical Properties and Estimated Environmental Fate of Brominated and Iodinated Organic Compounds

This chapter reviews the environmentally relevant physical-chemical properties, partitioning and reactivity properties of a selection of organobromine and organoiodine compounds. Substitution of hydrogens with bromine or iodine is shown to cause significant changes in vapor pressure, solubility in water, and hydrophobicity (octanol-water partition coefficient). These property changes are similar to those caused by substitution of hydrogen with chlorine, although there are quantitative differences attributable to the size and mass of the halogen atoms and to the effects on the strength of intermolecular interactions. The environmental implications of these changes are illustrated using simple multimedia partitioning models for volatile brominated and iodinated compounds, brominated flame retardants, and an iodinated X-ray contrast agent. The organobromine and organoiodine compounds are predicted to be less mobile in the environment than their organochlorine counterparts due to their generally higher reactivity and hydrophobicity, and lower volatility and solubility in water.