Copper, lead and cadmium loads and Behavior in urban stormwater runoff in Curitiba, Brazil

We investigate the presence and behavior of Cu, Pb, and Cd in runoff waters from a residential area located in the city of Curitiba, Brazil. Samples were collected in twenty-one stormwater events in an intermediate traffic way located in the Bacacheri watershed. Metal concentrations were similar to range values compiled worldwide and followed the order: Pb > Cu >> Cd. Unit loads were estimated to the watershed, which cover an area of 30 km(2), revealing values of 1520, 950, 25 kg for Pb, Cu, and Cd, respectively. Among the three metals, lead showed the greatest affinity for the suspended solids (82%) followed by Cd (66%) and Cu (48%). Meanwhile, an association of the metals with the organic matter in the dissolved phase, following the order Cu > Pb > Cd. Metal loads and behavior in urban runoff also depends on factors such as the first flush and the dry period preceding a storm event.