Sampling site 1 was a street in the city centre with heavy traffic, and a large number of public transport and public institutions. Sampling site 2 was an area with mainly residential development and no public transport. Sampling site 3 was an area with a road junction and a large car park in front of a supermarket, with less intense public transport than at site 1 and mainly residential development. The drainage system at each site has one
large central collector, which carries storm and snowmelt surface runoff directly to the River Mukhavets. The sample collection period was from December 2012 Nintedanib purchase to April 2013. The snow samples were collected during every fall of snow that was heavy enough to yield a sufficient amount of snow for analysis. The sampling vessels for snow (plastic, total volume 1.5 L for each sample) were placed in a green area of each site for 12 hours during snow falls to prevent any accidental contamination of the samples (e.g. by traffic, litter or pets). After the samples of snow had been taken to the laboratory, they were melted at room temperature and analysed within 24 hours. Winter in Belarus is characterised by successive periods of cold and warm weather. During the sampling period, thaws warm enough to produce runoff (including the final snow melt in April) occurred several times,
and each time the runoff was sampled and analysed. The snowmelt surface runoff was sampled at the ends of the drainage pipes that carry effluent from the target sites selleck screening library to the River Mukhavets; the samples were collected in clean plastic vessels (1 L volume for each sample) and analysed within 24 hours. Four snow samples and six runoff samples were taken from each site. The contaminants were analysed by standard methods (Standard Methods 1992, Aleshka 1997). Each parameter was analysed
in two parallel measurements. TSS were measured gravimetrically. Paper filters (pore size 2–3 μm) were weighed in weighing bottles. Then 100 mL of a sample (or a smaller volume diluted to 100 mL) Selleck Rucaparib was passed through the filter, the filter in the same weighing bottle was dried at 110 °C, cooled to room temperature and weighed again until constant weight. The content of TSS was calculated as the difference between the two weights. The concentration of chloride ions was measured by titration against silver nitrate and potassium chromate as indicator. The concentrations of nitrate, phosphate and ammonium ions were measured photometrically on an MS-122 PROSCAN Special Instruments (2010) spectrophotometer (Department of Chemistry, A. S. Pushkin Brest State University). The determination of phosphate ions was based on the reaction of phosphate ions with partly reduced hexavalent molybdenum resulting in the formation of a blue-coloured complex. The determination of ammonium ions was based on their ability to form a yellow-brownish compound with Nessler’s reagent.