Characterization of Environmental Pollutants in Sediment Collected during Street Sweeping Operations to Evaluate its Potential for Reuse

Abstract

Street sweeping is a routine roadway maintenance activity that functions as a nonstructural stormwater best management practice. Further, the road-deposited sediment collected during sweeping operations has the potential for beneficial reuse in a number of different applications but first must be characterized in terms of its toxicity to ensure that it is safe to do so. This study provides a chemical characterization of this material regarding heavy metals, polycyclic aromatic hydrocarbons, and oil and grease, and attempts to predict the concentration of these contaminants using average daily traffic, land cover, and particle size. Seventy-nine locations were selected from six average daily traffic (ADT) categories ranging from 1–400 to greater than 10,000 vehicles per day and four land cover categories including developed, open space; developed, low intensity; developed, medium intensity, and developed, high intensity. Average concentrations of As, Pb, Se, Ba, Cr, Ag, Cd, Cu, and Zn were 0.39, 7.3, 0.32, 14, 6, 0.046, 0.83, 0.89, and 30 mg/kg, respectively. The average total polycyclic aromatic hydrocarbons (PAH) concentration of all 79 sites was 17,000 μg/kg. Oil and grease concentrations in the material ranged from 34 to 3,400 mg/kg. The results showed that both average daily traffic and land cover cannot be used to predict the contaminant load of this material. However, a strong correlation was observed between particle size and the concentrations of all heavy metals and PAHs.