Abstract:

In order to explore the relationships between magnetic properties and environmental pollutions, street dust samples from four functional districts (Qingshan, Hongshan, scenic spot of East Lake, development zone of East Lake) of Wuchang region were collected, and their magnetic parameters including  magnetic susceptibility, frequency dependent susceptibility, isothermal remanent magnetization, demagnetization coefficient and magnetic hysteresis were determined. The results demonstrate that magnetic remanence carriers are dominantly soft magnetic minerals which belong to ferrimagnetic minerals and  magnetite particles in the samples present characteristic of low values of coercivity. Distribution patterns of saturation isothermal remanent magnetization (SIRM)are influenced by industrial activities, vehicle flow, and road conditions. SIRM data are good indicators for environmental pollutions in the chosen four districts: heavy contamination in the Qingshan industrial district and moderate contamination in the other three districts. In addition, distribution patterns of hard isothermal remanent magnetization（HIRM）indicate the special source of antiferromagnetic minerals originating from road traffic. Due to the excessive  flow of freight cars and heavy vehicles, development  zone of East Lake and Qingshan industrial districts posses higher HIRM values than Hongshan and scenic spot of East Lake. In total, street dust samples from Wuchang region show a higher concentration of magnetic minerals compared with other domestic metropolis such as Lanzhou, Xi’an, Nanjing and Xuzhou, indicating the urban environment need to be further protected and improved.

Key words: Wuchang region, street dusts, magnetic properties, environmental pollution