Mutagenic and carcinogenic hazards of settled house dust. II: Salmonella mutagenicity.

Settled house dust (SHD) is a complex mixture that contains numerous chemical contaminants. Very little is known about the hazards of SHD as compared to other complex matrices such as air and soil. In this study, the mutagenic hazards associated with the extracts of sieved dust from 52 homes were examined using the Salmonella Mutagenicity Test. All of the SHD samples displayed mutagenic activity and the mean mutagenic potencies ranged from 2300to 23 600 revertants per gram. Testing with various Salmonella strains revealed a predominance of frameshift mutagens in the dust samples. Analyses showed that polycyclic aromatic hydrocarbons (PAHs) were likely responsible for a quarter of the mutagenic activity of the SHD samples. In an effort to identify factors that influenced dust mutagenicity, the relationships between SHD mutagenicity and household activities were investigated. Mutagenicity was positively correlated with parameters such as the time since last vacuuming (r2 = 0.11, p < 0.05) and the number of people living in the home (r2 = 0.11-0.43, p < 0.05). However, the causative factors responsible for these relationships remain unclear.