Evaluation of Heavy Metal Contamination for Urban Soils

Since an increasing number of urban dwellers have come to recognize the close relationship between urban soils and water and air quality, as well as the growing popularity of urban agriculture, concern regarding soil contamination is on the increase. The objective of this research was to investigate the mobility of the heavy metals (lead and zinc) in contaminated urban soils. Soil samples from downtown Montreal, Canada were collected. The concentrations of lead and zinc of some soil samples were highly elevated, with the highest concentration being 2000 mg/kg (the standard limits for both metals are 300 mg/kg). Soil column leaching tests were carried out and they indicated that zinc has a higher mobility in the soils than lead. With this knowledge of heavy metal mobility in soils, the soil decontamination schemes can be designed or the potential impact of these soils can be evaluated.