Trace Metals in the Bed Sediment of Small Urban Streams

摘要

Trace metals (TMs) are still a serious problem in urban streams because of their toxicity and continuing significantlevels in the aquatic environment, especially in bed sediments. Concentrations of Cd, Cr, Cu, Ni, Pb and Zn weremonitored in the sediments of several small streams in the Prague area. These streams differ in the main source of pollution(combined sewer overflow - CSO, storm water drain – SWD, or waste water treatment plant - WWTP). The potentialTMs hazard was assessed by several indexes, and the dependence of TMs concentrations on various sediment materialcharacteristics was evaluated. The bioavailability of TMs was also assessed by comparing the binding strength of metalsin the sediment and their concentrations in aquatic organisms in these creeks. Of the metals studied, Cd is the most availablefrom sediments, but the other metals were also easily released from the sediment to the liquid phase. There were alsodifferences in TMs bioavailability from sediments of creeks with different main pollution source, and was higher in creeksimpacted by WWTP and SWD.