Mutagenic activity of airborne particulates at non-industrial locations

Abstract

Many studies indicate that aerosols in the ambient atmosphere may have mutagenic properties. Most of these investigations were conducted in industrial or urban areas or near specific sources. The purpose of our studies was to assess the variation in mutagenesis at non-industrial locations over a prolonged period of time using a bacterial test system, the Salmonella-microsome test (TA98) and to compare these mutagenic effects with those obtained in a mammalian test system, the sister-chromatid exchange (SCE) test. Samples were taken every 4th day over a period of 4 months at a background location (Terschelling) and 12 months at a rural location (Wageningen). Particulate matter was collected on glass-fiber filters during 24 h from about 2400 m 3 of air with the standard high-volume technique. After Soxhlet extraction with methanol for 8 h and evaporation to dryness, the residue was dissolved in DMSO. In the Salmonella-microsome test, particulate matter derived from 10–60 m 3 air was tested per plate with and without the addition of liver homogenate. At both the background and rural locations, mutagenicity varied markedly with time. Mutagenicity at both locations was positively correlated ( r = 0.80, n = 22, P < 0.01). On days with northern and western winds no or only a slight increase in the number of mutants was found, whereas on days with a wind from southern or eastern directions the mutagenicity generally was much higher at both locations. In the 1-year-period study in Wageningen the relation between mutagenicity and wind direction in segments of 60° was established. Mutagenicity was strongly correlated with wind direction but not with other meteorological factors such as wind speed.