Polybrominated dibenzo-p-dioxins and dibenzofurans

This environmental health survey evaluates the risks to human health and to the environment posed by exposure to polybrominated dibenzo-p-dioxins (PBDDs) and polybrominated dibenzofurans (PBDFs).

These are the unwanted by-products in various industrial and combustion processes.

The text discusses analytical methods for the detection and analysis of these toxins.

The available evidence confirms the formation of PBDDs and BBDFs during fire accidents, especially when electrical appliances are involved, during the use of flame retardants and fire extinguishers, during waste disposal and treatment, and during combustion processes in engines.

Evidence suggests that occupational exposure may occur in a variety of workplaces, especially in the plastic and recycling industries, where brominated flame retardants or products containing them are used.

Some monitoring results are also available for exposures in workplaces equipped with a number of electrical appliances continually in use, such as displays and computer monitors. A section on environmental behaviour cites evidence that these compounds are similar to their chlorinated analogues, with preferential distribution to carbon- or fat-rich compartments and long persistence.

Data on kinetics and metabolism are assessed in the next section, which concludes that these compounds are distributed throughout the body, with major deposits found in liver and adipose tissue, followed by skin and muscle.

Data from experimental studies of toxicity support the conclusion that the thymus, lymphatic tissue and liver are the principal targets of toxic action.

Thymus atrophy and other signs of immunotoxicity were the effects most consistently seen in laboratory animals.

Data on human exposures and health effects were judged inadequate to support an assessment of hazards for the general population or a recommended safe level of exposure.

The report concludes that the amount of bromide-containing waste will be increasing in the future, and that electronic scrap from casings and printed circuit boards of computers will reach the waste streams as a potentially major source of release to the environment.