Analysis of heavy metals in road-deposited sediments

Abstract

Road-deposited sediments were analysed for heavy metal concentrations at three different landuses (residential, industrial, commercial) in Queensland State, Australia.The sediments were collected using a domestic vacuum cleaner which was proven to be highly efficient in collecting sub-micron particles. Five particle sizes were analysed separately for eight heavy metal elements (Zn, Fe, Pb, Cd, Cu, Cr, Al and Mn). At all sites, the maximum concentration of the heavy metals occurred in the 0.45-75 m particle size range, which conventional street cleaning services do not remove efficiently. Multicriteria decision making methods (MCDM), PROMETHEE and GAIA, were employed in the data analysis. PROMETHEE, a non-parametric ranking analysis procedure, was used to rank the metal contents of the sediments sampled at each site. The most polluted site and particle size range were the industrial site and the 0.45-75 m range respectively. Although the industrial site displayed the highest metal concentrations, the highest heavy metal loading coincided with the highest sediment load, which occurred at the commercial site. GAIA, a special form of Principal Component Analysis, was applied to determine correlations between the heavy metals and particle size ranges and also to assess possible correlation with Total Organic Carbon (TOC). The GAIA-planes revealed that irrespective of the site, most of the heavy metals are adsorbed to sediments below 150 m. A weak correlation was found between Zn, Mn and TOC at the commercial site. This could lead to higher bioavailability of these metals through complexation reactions with the organic species in the sediments.

The sources, impact and management of car park runoff pollution: A review

“…In contrast, for a similarly sized university parking lot, Kayhanian et al (2012) found that only around 5% of the collected particulate mass was less than 38 µm in diameter. There is, however, agreement on particle numbers with car park surface dusts containing predominantly fine particles with reports of 97% being less than 38 µm (Kayhanian et al, 2012) or over 90% being below 150 µm (Herngren et al, 2006). Since street sweeping practices only efficiently remove coarser particles (German and Svensson, 2002), the problems posed by the finer, more contaminated particles will remain a significant problem in runoff where they tend to dominate on a mass distribution basis (Kayhanian et al, 2012).…”

“…In a separate review, Sorme (2003) The concentrations of a range of metals reported in road dusts from a supermarket car park and from urban areas with similar characteristics to car parks are presented in Table 2. The studies were conducted in the same geographical region but represent diverse ranges of metal concentrations deriving from similar land-use types with the results reported by Herngren et al (2006) being two to three orders of magnitude lower than those of Gunawardana et al (2012). There is no obvious explanation for these large variations although it is accepted that differing metal concentrations will occur in these environments due to factors such as traffic density, weather conditions and neighbouring land-use activities.…”

“…For deposited dusts, the relationship between mass and particle size fractions is not always consistent although there is a tendency for the majority of the mass to reside in the finer particle fractions which is the opposite of the usually reported trend for urban surface sediments (Li et al, 2006;Chiew, 2002, 2004). Herngren et al (2006) compared 3 different urban sites and found that the largest amount of sediment collected was from a large supermarket car park (570 car parking spaces) with the finer than 75 µm size fraction contributing 60.9% (Table 1). In contrast, for a similarly sized university parking lot, Kayhanian et al (2012) found that only around 5% of the collected particulate mass was less than 38 µm in diameter.…”

“…lighting, barriers and signage), general litter, accidental spills and erosion of soils from surrounding areas via both direct and indirect deposition routes. Traffic has been identified as an important contributor of particulate materials in urban areas with specific sources including the wear and tear of car bodies and engines, abrasion of brakes and tyres, exhaust emissions, friction-assisted break-up of paving and road materials and de-icing/anti-skid materials (Gunawardana et al, 2012;Herngren et al, 2006;Sorme, 2003;Thorpe and Harrison, 2008;Westerlund, 2005). Thorpe and Harrison (2008) distinguished between particulate matter emitted from exhaust emissions and that derived from non-exhaust emissions and concluded that they contributed similar loads to local traffic related emissions.…”

Size distribution and diffuse pollution impacts of PAHs in street dust in urban streams in the Yangtze River Delta

“…The input of PAHs from point sources has gradually decreased because of enhanced discharge control (Schneider et al, 2001), while the input of PAHs from urban stormwater runoff has increasingly been reported as one of the most frequent causes of surface water pollution (Brenner et al, 2002;Murakami et al, 2004). PAHs in stormwater runoff tend to partition onto solid particles (Li et al, 2006), and street dust particle in urban runoff act as a transport medium for PAHs (Brown and Peake, 2006;Herngren et al, 2006). PAHs in street dust have various origins: weathering of materials from street surfaces, automobile exhausts, tyre particles, and atmospherically deposited materials (Takada * Corresponding author.…”