A survey of metal contaminants in an urban snow disposal facility

This study was carried out to evaluate the level of heavy metal contamination in an urban snow disposal site that is located in a mid-sized city in Canada during the winter season of 2024–2025. The snow disposal site for this study has the capacity to warehouse an enormous quantity (500,000 cubic meters) of snow during the winter months. It is located in a city with light manufacturing and services industries and does not have heavy industries with smelting, refineries, or coal-fired power plants. In this urban setting, snow becomes a useful sample for assessing the level of contaminants produced primarily by automobile traffic. The results of this survey indicated the presence of metals that would normally be found in soil or aggregate materials, including calcium (Ca), magnesium (Mg), iron (Fe), and manganese (Mn). In snow samples, metals that were present as contaminants, such as nickel (Ni), copper (Cu), and zinc (Zn), were also detected. Zn, which is often associated with tire wear, was detected in the range of 0.1–2.8 µg mL ^− 1, and Fe, which is often associated with the wear of brake pads, was detected in the range of 3–20 µg mL ^− 1 in melted snow samples. Other metal contaminants that were found in both soil and snow samples included Cu, Ni, cobalt (Co), lead (Pb), and cadmium (Cd). These metals were found in concentrations in melted snow samples (< 10 ng mL ^− 1 ) primarily as particulate or particulate-bound metals. Although these metals were much higher in concentration (0.05-20 µg g ^− 1 ) in the sand/aggregate samples of the snow disposal site, they were well below the Canadian Soil Guidelines for these metals.