Abstract

Diffuse pollution formed during a surface runoff on paved surfaces is a source of heavy metals (HMs) of various origin. This research study indicates the connection between bottom sediments of retention tanks located on urban streams and road sweeping wastes (RSW) that migrate during surface runoff to the stormwater drainage systems with discharge to the retention tanks. Moreover, we test the primary sources of HMs in RSW by analysing the mechanical wastes (MW) produced by vehicles in order to track the relationship between car parts and HMs deposited in the retention tanks receiving the surface runoff from streets. To identify the origin ofHMs diverse source tracking approaches were used: statisticalmethods, Pb isotope ratios, and the flag element ratio approach.MWpresented a very highHMs content (max observed values inmg/kg d.w.: 10477-Zn, 3512-Cu, 412-Pb, 3.35-Cd, 226-Ni, and 633-Cr), while for RSWthe HMs content was similar to the bottom sediments. The total carcinogenic risk raises concerns due to the Cr content. The source of Zn was tyre wear and traffic. Ni, Cr, Fe, and Cd were correlated to Zn and shared a common/similar origin. PCA suggested that Cu features quasiindependent behaviour. The Pb isotopic ratios of RSWindicated Pb enrichment originating fromcoal combustion, while the gasoline and diesel source of Pb was excluded. The Pb isotopic ratios characteristic for MW were in within the following ranges: 1.152–1.165 (206Pb/207Pb), 2.050–2.085 (208Pb/206Pb), and 2.350–2.418 (208Pb/207Pb). The complex analysis of HMs origin confirmed the motorization origin of HMs: Zn, Cr, Ni, and Cd, except Pb (coal combustion as the main source) and Cu (non-uniform origin). The results of various source tracking methods were coherent, but Pb isotope ratios alone brought important information allowing to link Pb in sediments to the atmospheric deposition of coal combustion products.

Citations

Authors (5)