THE CONTENT OF LEAD, CADMIUM AND MERCURY IN SEDIMENTS FROM RAINWATER RESERVOIRS SITUATED ALONG THE NATIONAL ROAD 4

The paper aimed at determining the pollution level of sediments collected from reservoirs receiving rainwater. The sediments were sampled from 11 reservoirs on three dates: in May 2007, in April 2008 and in June 2008 in the following localities: Sulkow, Biskupice, Bodzanow and Suchoraba situated at a distance of ca 15 from each other. The contents of lead, cadmium, mercury and organic matter were assessed in the sediments. Lead content in the analysed sediments ranged from 9.87 to 61 mg .kg(-2) with average for all samples 28.08 mg . kg(-1). Mean cadmium concentration in the studied. sediments was 0.637 mg . kg(-1) and fluctuated from 0.20 to 1.58 mg Cd kg(-1) The quantities of mercury assessed in the sediments from rainwater reservoirs ranged from 0.337 to 0.864 mg . kg(-1). Considerable differences between studied metal concentrations were assessed among the studied reservoirs, however the trends of differences were similar at each sampling. Generally, the levels of cadmium and mercury assessed in the analyzed sediments were comparable to the sediments from urbanized areas of various cities in the world, whereas lead level in the sediments of the analysed reservoirs was generally much lower than reported for similar materials in literature. Regularly decreasing contents of all elements with growing distance from the Krakow agglomeration was noted. The reservoir situated closest to Krakow, in Sulkow is located 7 km from the city boundaries and borders on Wieliczka town, whereas the reservoir in Suchoraba is located 17 km from Krakow. At this distance metal concentrations in the sediments from rainwater reservoirs were diminishing several times, which suggests considerable effect of urban pollution on metal level in these sediments.