Spatial Distribution of Metals and Associated Risks in Surface Sediments Along a Typical Urban River Gradient in the Beijing Region

Abstract

Surface sediments from Beiyun River located in the rapidly urbanized Beijing metropolis were collected and analyzed for heavy metals (As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn) to investigate their spatial distribution pattern, ecotoxicology and source identification. Results indicated the average heavy metal concentrations of Cd, Cr, Cu, Pb, and Zn were approximately 4, 2, 3, 2, and 4 times higher than their background values. Spatially, we found the concentrations of heavy metals made significant change in four sections along urbanized river gradients. The contents in midstream of urban region and farmland region (section 2 and section 3) were greater than those in upstream (section 1) and downstream (section 4). However, one-way analysis of variance for spatial analysis suggested there were no significant differences between mainstream and tributaries. The geo-accumulation index (I ) used to assess the sediment quality exhibited there was a decreasing order for the average I of measured heavy metals: Zn (0.82) > Cd (0.53) > Cu (0.50) > Cr (- 0.08) > Pb (- 0.45) > Ni (- 0.96) > Mn (- 0.97) > As (- 1.01), whereas they had different "high-low" orders at different sampling transects. Ecological risk index values showed that section 2 and section 3 revealed a high and moderate ecological risk, respectively. Furthermore, principal component analysis indicated the first principle component explained 64.73% of total variance with the main pollutants of As, Cr, Ni, Zn, and Cu which were probably controlled by the mixed sources covering natural factors and anthropogenic input.

Distribution and assessment of the environmental risk of heavy metals in Aguada Blanca reservoir, Peru

“…The results are shown in Table 5, where the Cd value (1.21 ± 1.45) presents values greater than 0 (Igeo> 0), and presented a degree of contamination from moderately to heavily contaminated, while As (-0.78 ± 0.69), Pb (-0.98 ± 0.62), Cu (-1.05 ± 0.64), Zn (-1.71 ± 0.47) and Cr (-4.18 ± 0.40) do not present contamination for the reservoir. The high EF and Igeo of Cd would be a risk in the reservoir in relation to other evaluated elements, and compared to other studies, our Cd Igeo would be slightly higher (Abata, 2013;Ekengele et al, 2017;Li et al, 2018;Marziali et al, 2017;Zhang et al, 2017) and less equal to studies where the concentration of Cd is described as a strong anthropogenic effect (Cáceres Choque et al, 2013;Çevik et al, 2009;Li, 2014;Nowrouzi and Pour Khabbaz, 2014).…”

Spatial Distribution Characteristics and Sources of Nutrients and Heavy Metals in the Xiujiang River of Poyang Lake Basin in the Dry Season

“…Principal Component 3 explained 15.5% of the variance differentiation, in which the COD Cr , Cu, and As had strong and medium positive loads, respectively (Table 4). The Cu and As mainly originated from urban and industrial activities, such as energy production, mining, metal smelting and refining, manufacturing processes, automobile exhausts, and waste incineration [39,51,52]. The COD Cr has been found to be a good measurement of the redox conditions [53].…”

Heavy metals contamination in sediments of Bharalu river, Guwahati, Assam, India: A tributary of river Brahmaputra

“…Surface soil’s metals can come from natural and multiple anthropogenic sources [ 13 ]. Point sources of pollutants in urban river sediments must be evaluated and identified regularly to reveal the impact of city expansion on the river ecosystem [ 13 ].…”

“…Surface soil’s metals can come from natural and multiple anthropogenic sources [ 13 ]. Point sources of pollutants in urban river sediments must be evaluated and identified regularly to reveal the impact of city expansion on the river ecosystem [ 13 ]. Heavy metal contamination in aquatic sediments has a longer residence time, which may aid in more effective monitoring of pollution [ 14 ].…”