Atmospheric deposition of polycyclic aromatic hydrocarbons on the Lake Balaton, Hungary

Abstract

The concentration of polycyclic aromatic hydrocarbons (PAHs) in atmospheric precipitation and aerosol samples was monitored on the Lake Balaton to examine the seasonal variations and depositions. Samples were collected at Tihany located on the north part of the Lake Balaton between April 2002 and April 2003. Aerosol particles were sampled on quartz fiber filters using low volume sampler (1.2 m 3/h). For the determination of the size distribution of PAHs, aerosol was collected on aluminium foils by an eight-stage Berner-type low-pressure impactor (31.2 m 3/h, cutoff diameters: 0.0625–8 μm). The dry deposition velocities on water surface as a function of the particle diameter were estimated. The collection of rain and snow samples was performed by an automatic wet-only sampler. The seasonal mean concentration of the ΣPAHs in precipitation was found as 149, 96, 586, and 1136 ng/l in spring, summer, autumn, and winter, respectively. In the atmospheric aerosol samples, the seasonal mean concentration of the ΣPAHs varied from 3.2, 1.7, 6.2, and 31 ng/m 3 in spring, summer, autumn, and winter, respectively. It was found that PAHs generally showed the maximum concentration in the 0.25- to 1.0-μm size range in every season. Wet (280 μg/m 2×year) and dry (70 μg/m 2×year) deposition rates were calculated, and pollution loading of PAHs from the atmosphere to the Lake Balaton was obtained as 170 kg/year of wet and 40 kg/year of dry deposition.