2016 Volume 26 Issue 1 Pages 1-7
To estimate the risks associated with long-term human exposure to potentially mutagenic compounds, it is important to measure long-term trends in the concentrations and activity of these compounds in the environment. Samples of total suspended particulates (TSP) have been collected upon a quartz fiber filter every 6 days for the past 20 years (1980-2002) from ambient air using a high-volume air sampler placed on the rooftop of the National Institute of Public Health building in Minato, Tokyo, Japan. The mutagenicity of dichloromethane extracts of TSP samples, which divided according to season, were assayed by Ames microsuspension assay using Salmonella strains TA100 and TA98, both with and without metabolic activation system (S9 mix). Mutagenic activities (rev/m3) were calculated from the dose–response curves of the samples and from those of reference airborne particles collected by the massive sampler. Mutagenic activity increased in the first decade (1980-1990) but slowly decreased in the second decade (1990-2002). Annual average mutagenicity in TA98 was mostly higher than in TA100. Mutagenic activity was higher in autumn and winter than in spring and summer.