Brominated flame retardants; Toxicity and ecotoxicity

1. Method

The preliminary result of the substance flow analysis project indicates that the substances in table 1 are used in Denmark, as pure substances or in manufactured goods. A health and environmental assessment was made, if possible, on these substances after the method outlined below.

Table 1. Chemical substances selected

Data were retrieved primarily from well recognised handbooks and reviews of toxicological and ecotoxicological relevance. Furthermore, a data search was made in the draft EU risk assessments and in relevant bibliographic databases. In appendix 3 of this re-port is a list of used standard sources. This list is part of CETOX's standard operating procedure for data screening of chemical sub-stances and is a further development of the strategy described by the Danish EPA in 1993 "Retningslinier for datasøgning og udarbejdelse af klassifikationsskemaer undtagen miljøfarlige egen-skaber" (Miljøstyrelsen 1993).

Based on the data screening the substances were divided into three groups: 

1. Substances with some data
2. Substances with few data
3. Substances with (nearly) no data

It is known from experience that it is often difficult to find relevant data on chemical substances, when there is almost no information in the standard sources. Therefore and because of limited resources, it was decided not go further with those substances in this project.

A more thorough data search was made on each of the substances in groups 1 and 2 in the following databases: Toxline, HSDB, RTECS, IRIS and CCRIS. A more focused data search was per-formed in the databases Medline (from 1990), Embase (from 1990), Biosis (from 1993) and Toxline with respect to endocrinological and immunotoxic effects, effects on human beings and contents of the substances in body fluids. Further a focused data search was performed in the database Current Contents (from 1994-1998) for data with ecotoxicological relevance.

On few occasions, and when no data were available, structure ac-tivity relation analyses was used in the environmental assessment. In these cases, the similar chlorinated compound was used on a "worst case" basis. Especially the potential bioaccumulation of BFR is difficult to assess as the broadly accepted use of the octanol-water partition coefficient may lead to an overestimation of the bioaccumulation because the potential of a substance to bio-concentrate decreases above certain molecular dimensions. It has been proposed that chemicals with a molecular weight above 700 should not be considered potentially bioaccumulative (European Commission, 1996). However, this cut-off value has been subject to criticism and an alternative cut off value of 1000 has been proposed (SCTEE, 1999).

Based on the data retrieved, a short toxicological and ecotoxicological profile was made on each substance. Each profile was closed by a conclusion on the amount and quality of data retrieved and on the possible hazards of the substance.