Platinum-group and other traffic-related heavy metal contamination in road sediment, Guangzhou, China

• Published in: Journal of soils and sediments 2012-06, Vol.12 (6), p.942-951
• Main Authors: Zhong, Lifeng, Li, Jie, Yan, Wen, Tu, Xianglin, Huang, Weixia, Zhang, Xiaohua
• Format: Article
• Language: English
• Subjects: Anthropogenic factors; Cadmium; Chemical composition; Contaminated sediments; Contamination; Earth and Environmental Science; Environment; Environmental Physics; Factor analysis; Heavy metal content; Heavy metals; Lead; Mass spectrometry; Metal concentrations; Metropolitan areas; Motor vehicles; Multivariate analysis; Particulate matter; Platinum; Roads; Sec 1 · Sediment Quality and Impact Assessment · Research Article; Sediment samplers; Sediments; Soil Science & Conservation; Statistical analysis; Tires; Zinc
• ISSN: 1439-0108; 1614-7480
• DOI: 10.1007/s11368-012-0527-8

Purpose Human exposure to particulate matter emitted from on-road motor vehicles includes complex mixtures of heavy metals from tyres, brakes, part wear, and resuspended road sediment. The purpose of this study was to determine the concentrations of 14 platinum-group and other traffic-related heavy metals in road sediment within the metropolitan area of Guangzhou, China, with a view to identifying their sources and assessing the extent of anthropogenic influence on heavy metal contamination of road sediment. Materials and methods Thirty-five samples of road sediment were collected. The concentrations of Cr, Mn, Ni, Cu, Zn, La, Ce, Mo, Cd, Pb, Ba, and Rh were measured by inductively coupled plasma–mass spectrometry. Pt and Pd were analyzed by isotopic dilution–inductively coupled plasma–mass spectrometry. Multivariate statistical analysis and enrichment factor methods were employed to identify the sources of these heavy metals and to assess anthropogenic influences on their occurrence. Results and discussion The mean concentrations of Pt, Pd, Rh, Cr, Mn, Ni, Cu, Zn, La, Ce, Mo, Cd, Pb, and Ba in the road sediment samples were 68.24, 93.15, 23.85, 147.5, 712.3, 47.24, 177.5, 1254, 47.50, 96.62, 4.91, 3.00, 198.1, and 641.3 ng g −1 , respectively. Very weak to significant linear positive correlations were found among the various heavy metals. The elemental composition of road sediment was dominated by five principal components. Three clusters were identified through cluster analysis, and enrichment factors were calculated relative to soils in China. The sources and degree of contamination of the heavy metals are discussed based on the results. Conclusions The mean concentrations of heavy metals are higher than background values, especially for Pt, Pd, Rh, Cd, and Zn. Four main sources are identified: (1) Pt, Pd, and Rh were derived from traffic sources; (2) La, Ce, Mn, and Ba were derived mainly from natural sources; (3) Cr, Ni, Cu, Mo, Cd, and Pb showed mixed traffic-industry sources; and (4) Zn originated mainly from industrial sources. Enrichment factor analysis supported this source identification and further indicated that contamination of road sediment in Guangzhou is extremely high for Pt, Pd, and Rh; moderate to very high for Cd, Zn, Pb, Cu, and Mo; and minimal for Cr, Ni, La, Ce, and Ba.