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.