Mercury in the topsoil and dust of Beijing City.

Research on mercury concentration in the dust and topsoil of Beijing City reveals the following conclusions: mercury concentration in Beijing topsoil and dust is middle compared to other mercury concentration studies and varies greatly in different sampling spots. Mercury concentration in the topsoil is between 0.019mg.kg(-1) and 0.966mg.kg(-1), it is about 2.11 times and 12.08 times of mercury concentration background in Beijing soil respectively. Mercury concentration in Beijing dust has a range of 0.053 to 1.378mg.kg(-1); the maximum mercury concentration in the Beijing dust in 2003 is about 2.2 times of that in 1992. These results show that mercury pollution in Beijing topsoil and dust are serious, and mercury tends to enrich in the dust compared to the adjacent topsoil. Mercury in topsoil and dust of Beijing City has obvious regional differentiation characteristics, which is highest in the center of Beijing City and lower away from the center to the suburbs. In detail, mercury concentration in the topsoil samples and dust samples are highest in Dongsi area and lowest in the blank spot. Mercury in Beijing's topsoil belonging to point pollution is mainly from local area; mercury in the dust belongs to non-point source pollution because the source of mercury in the dust is very complex. Natural factors and anthropological factors have certain effect on mercury concentration in the topsoil and dust, and anthropological factors have more effect. The results are very important to protect and enhance our environmental quality.