Substances in Urban Snow. A comparison of the contamination of snow in different parts of the city of Lulea, Sweden

The aim of the study was to investigate how the quality of snow varies with in a city. The study area is situated in the Lulea municipality, in norther n Sweden (lat. 65 degrees 35'N and long. 22 degrees 10'E). For this study, the city was divided into three different types of areas: housing areas, ci ty centre and outskirts. In one area of each type, sampling sites were sele cted. Snow samples were taken at nine occasions, once every fourteenth day in the city centre and in the housing area. Analyses were carried out for pH, con ductivity, suspended solids and both the total and dissolved concentration of phosphorus and selected metals. It was concluded that traffic or activit ies related to traffic were a major source of heavy metals and phosphorus i n urban snow, both in the city centre and in the housing area. Also, the ty pe of area and the design of the street were important for the quality of s now. A clear relation was found between the pH and the quantity of suspende d solids in the snow. Higher pH values were found in snow samples from site s with higher traffic loads, and lower pH values at sites, which were the n o-traffic sites, with small quantities of particles. The particulate and di ssolved substances in the snow behaved in different ways.