Environmental magnetic responses of urbanization processes: evidence from lake sediments in East Lake, Wuhan, China

Abstract

S U M M A R YWe present a study on the environmental magnetic response to urbanization processes from nine sediment cores from East Lake in Wuhan, China. The concentration of magnetic particles, heavy metals and organic matter in the upper 2-18 cm of the sediment cores have been significantly elevated due to the input of coarse magnetite grains from industrial (e.g. power generation and steelmaking) and other anthropogenic activities (e.g. vehicle emissions). Concentration-related magnetic parameters, such as magnetic susceptibility (χ ), saturation isothermal remanent magnetization and anhysteretic remanent magnetization, are significantly correlated with concentration of heavy metals and organic matter, for example, Pearson's correlation coefficients are 0.921 for χ -Cu, 0.660 for χ -Pb and 0.848 for χ -loss-on-ignition, respectively. The magnetic properties of the lake sediments document the pollution history caused by human impact on the lake catchment during urbanization. The environmental quality of the lake was fairly good before the 1960s. Magnetic, heavy metal and organic matter contents of the sediments were low and relatively constant, which indicates relatively stable natural inputs from the lake catchment. Pollution trends since the 1960s are reflected in downcore magnetic property variations of the lake sediment. The concentration of magnetic particles in the lake sediments started to increase since 1957, when the Wuhan Iron and Steel Company and the Qingshan Thermal Power Plant, which are located upwind of the lake, were built and put into production. Lake pollution was further aggravated since the acceleration of industrialization and urbanization in East Lake area in the 1980s, which is verified by the elevated concentration of heavy metals and organic matter in the sediments. The magnetic mineral concentration in the lake sediment increased continuously until it peaked in the 1990s and has remained a high level since then. These results suggest that magnetic properties respond sensitively to environmental status, and that the magnetic properties of sediments can provide an excellent record of the industrial and anthropogenic history in an urban lake catchment.

Impact of soil erosion and degradation on water quality: a review

“…In addition to the commercial activities mentioned early, further industrial plants, such as foundries and cement plants exist (Yang, Liu, Zeng, & Chan, 2009). More importantly, the Lake plays a substantial role in industrial and agricultural production, daily life, aquaculture, and tourism.…”

“…Moreover, the scale of built-up construction surrounding the East Lake is still expanding and the population is becoming denser . Therefore, the East Lake picturesque area faces severe ecological problems such as lake eutrophication affected by the large domestic sewage, oil waste from catering industry and the discharge of industrial and agricultural waste (Huang, Liu, Fang, & Zhao, 2013;Wilson et al, 2008;Yang et al, 2009), coal gasification (tar) and coking plants, and many more have been piled up in the Qingshan industrial vicinity.…”

Macroinvertebrate communities in the Big East Lake water network in relation to environmental factors

“…Historically, the BELWN was an open lake system connected to the Yangtze river before 1957. Due to the rapid urban development, the BELWN became a disconnected lake system and was isolated from the Yangtze river (Du, 1998;Yang et al, 2009;Huang et al, 2013). In 1950, the BELWN had abundant aquatic plants and clear water (Chen et al, 1975;Wu et al, 2003).…”

Magnetic properties of the road dusts from two parks in Wuhan city, China: implications for mapping urban environment

“…Their deposition thus may be associated with the enhancement of both magnetization and concentration of pollutants in environmental matters (e.g., topsoils, sediments, fly ashes, and road dusts, etc. ; Petrovský and Ellwood 1999;Ng et al 2003;Lu and Bai 2006;Magiera and Zawadzki 2007;Hanesch et al 2007; Sharma and Tripathi 2008;Lu et al 2009;Liu et al 2009;Yang et al 2007aYang et al , 2009Bućkol et al 2010). Xie et al (1999)'s study on the street dusts from Liverpool, UK, suggested that organic matter contents significantly correlate with some magnetic concentration-related parameters, and that the main magnetic carriers are a multi-domain (MD) ferrimagnetic phase with a small contribution of single-domain (SD) and antiferromagnetic grains.…”

“…Magnetic studies of roadside dust from Seoul, Korea, throughout a 13-month period, demonstrated that seasonal mapping using a mean apparent magnetic concentration (ACM) could be highly informative on the investigation of spatio-temporal pollution characteristics in urban areas (Kim et al 2009). These works have demonstrated that magnetic methods can be employed not only for identification of sources of contaminants, but also as a complementary tool for the routinely employed geochemical methods, which are known to be more time consuming, tedious, and expensive (Hoffmann et al 1999;Xie et al 1999Xie et al , 2001Ng et al 2003;Spiteri et al 2005;Prajapati et al 2006;Magiera and Zawadzki 2007;Hanesch et al 2007;Sharma and Tripathi 2008;Blaha et al 2008;Lu et al 2009;Yang et al 2007aYang et al , 2009Kim et al 2007Kim et al , 2009.…”