Seasonal Variations of Ten Metals in Highway Runoff and their Partition between Dissolved and Particulate Matter

Abstract

Knowledge of differentiation of pollutants in urban runoff between dissolved and particulate matter is of great concern for a successful design of a water treatment process. Seasonal variations in pollutant load are of equal importance. Ten metals (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn), as dissolved and particulate bound, was studied in the runoff from a major urban highway during a winter season and its following summer. Studded tyres and winter salting were expected to have an impact on the runoff water quality. The dissolved part of Al, Cd, Co, Cr, Mn and Ni was significantly higher in winter in comparison with summer (p<0.01). For Fe, however, the dissolved part was lower during winter. No significant difference was found for Cu, Pb and Zn between the two seasons. The mass concentration (mg kg −1 ) for all metals was significantly higher over the summer except for Al and Co, which showed a higher mass concentration during the winter. The concentration of selected metals vs. total suspended solids (TSS) showed a linear relationship (r 2 >0.95) during winter runoff events except for Cd. A good correlation (r 2 > 0.90) was also found for the summer period for Al, Cu, Fe, Mn, Ni and Zn. It is suggested that the metal pollutant load during winter could be assessed indirectly by measurement of TSS.

A novel approach for road runoff sampling

“…5 features one of these samples, showing extraordinarily high metal concentrations compared to the rest of the events. This confirms the results of other studies [14,18,21] which identify the reasons as the pollutant-trapping capability of the roadside snow matrix and the increased corrosion caused by de-icing agents. Apart from the snow bank acting as a repository for coarser metal particles, the additional adsorption of fine airborne particles to the snow crystals may also contribute to the overall accumulation.…”

“…The partitioning of metal contaminants between particulate and dissolved forms in road runoff is discussed in detail by a handful of previous studies, e.g. : [13,14,16,18].…”

Relationship between Urban Runoff Pollutant and Catchment Characteristics

“…Europe: Stotz and Krauth (1994), Barbosa and Hvitved-Jacobsen (1999), Legret and Colandini (1999), Pettersson et al (1999), Gnecco et al (2005), Hallberg and Renman (2006), Hallberg et al (2007).…”

Impacts of Salinity on Saint-Augustin Lake, Canada: Remediation Measures at Watershed Scale

“…Values were low taking into account the traffic intensity of Highway A40 [34] and when compared with the TSS concentration ranges reported for road runoff in other studies: 18-3165 mg/L [33], 13-4800 mg/L [35], and 1-5100 mg/L [2]. Regarding rainfall, a positive relation was observed among the peaks in TSS concentration (Figure 8d) and the peaks in total precipitation (Figure 7), but significant correlations could not be established (Table 3).…”

“…Regarding rainfall, a positive relation was observed among the peaks in TSS concentration (Figure 8d) and the peaks in total precipitation (Figure 7), but significant correlations could not be established (Table 3). The concentration of TSS in road runoff is dependent on a number of factors including storms events, rainfall intensity and duration, an antecedent dry weather period, wind, traffic volume and type, traffic during storms, watershed extension, land use in surrounding areas (residential, urban, and agricultural), TSS particle size, and so on [35][36][37][38]. The complexity of interactions among these factors may account for the lack of significant correlations between TSS concentration and the climatic data.…”