Mutagenicity of bis- and mono-(2,3-dibromopropyl)phosphate, and their salts used as flame retardants, in the Salmonella/microsome system.

The mutagenicity of pure synthesized samples of bis(2,3-dibromopropyl)phosphate (bis-BP) and mono(2,3-dibromopropyl)phosphate (mono-BP) against Salmonella typhimurium TA100 was examined in relation to microsomal activation of tris(2,3-dibromopropyl)phosphate (tris-BP). Both mono- and bis-BPs were weak direct mutagens. Their mutagenicities increased with S9 mix, but the rates were much less than that of tris-BP. The magnesium and ammonium salts of mono- and bis-BPs were also prepared and their mutagenicities were examined with S9 mix in relation to 2 commercial flame retardants (our abbreviations: DB-1 and DB-2). In both mono- and bis-BP series, an apparent increase of mutagenicity was observed in the order: ammonium salt greater than magnesium salt greater than free acid. On the other hand, mono-BP and its salts are usually more active than the corresponding bis-BPs independently of the kind of cation. DB-1 (DB-2), however, is more potent than the magnesium (ammonium) salts of mono- and bis-BPs, the constituents in DB-1 (DB-2). No synergistic effect between mono-BP salts and bis-BP salts was observed. The different unknown mutagenic compounds in DB-1 and DB-2 are suggested.