Magnetic properties of street dust from Chibi City, Hubei Province, China: Its implications for urban environment

Magnetic measurements and heavy metal analyses were performed on street dusts from the main urban area of Chibi (赤壁) City, Hubei (湖北) Province, China. Results revealed that a PSD/MD (pseudo-single-domain/multi-domain) magnetite-like phase dominates the magnetic phases of the street dust. Concentration-related magnetic parameters, such as magnetic susceptibility (χ), anhysteretic remanent magnetization (ARM), and saturation isothermal remanent magnetization (SIRM) of samples increased in the main roads but appeared lower in the landscape area of the Lushui (陆水) Lake and closely correlated with the concentration of heavy metal Fe, Cu, and Co, and the correlation coefficients are 0.786 for Fe-χ, 0.548 for Cu-χ, and 0.580 for Co-χ, respectively. However, much strong correlations between SIRM and the concentrations of heavy metal suggest that SIRM is a better indicator for heavy metal pollution in the street dust in the study area. The magnetic particles in the street dust are mainly derived from anthropogenic activities, such as vehicle emissions, abrasion of tires, coal combustion, cement works, and building materials. These results make it possible to use magnetic techniques as simple, rapid, and nondestructive tools for assessing the heavy metal pollutions in urbanization process.