The characteristics of topsoil magnetic susceptibility around East Lake, Wuhan: its implications for environmental pollution

摘要

The relationship between magnetic susceptibility and the content of heavy metals of topsoil around East Lake in Wuhan, China, were investigated to examine the feasibility of magnetic susceptibility measurement for mapping the heavy metals pollution status in this region. Parallel distribution pattern between topsoil magnetic susceptibility and concentration of heavy metal elements were observed, which correspond with the degree of anthropogenic and industrial activities. The highest magnetic susceptibility, content of heavy metal elements and correlation between them were found nearby Wuhan Iron and Steel Company (WISC) and Qingshan Thermal Power Plant (QSTPP). The mean concentration of Cu, Pb and Zn are 2.81, 2.18 and 3.01 are times higher than their corresponding background values respectively in the region nearby WISC and QSTPP. A significant correlation between magnetic susceptibility and the concentration of heavy metal Cu, Fe, Pb and Zn was observed near WISC and QSTPP. Heavy metal elements in topsoil are from different sources at these four sampling sites. Along East Lake road situated in beauty spot, the heavy metals in topsoil are mainly from parent materials; Along Qingwang Road with heavy traffic, the heavy metals elements not only from parent materials, traffic and transportation also are non-neglectable source; In Beiyangqiao-Huguang village situated in the downwind region of WISC and QSTPP , the sources of heavy metal elements are the most complex, except for parent materials and the wind-blown fly ash emitted by WISC and QSTPP, agricultural activities also an significant source of heavy metal; The magnetic particles carrying heavy metals emitted by WISC and QSTPP responses for the significant enhanced magnetic susceptibility and the concentration of heavy metals near WISC and QSTPP. These results confirm the applicability of topsoil magnetic susceptibility screen as a simple, rapid and effective mean for monitoring the pollution status in urban soil.