Caracterização do carreamento de poluentes de superfícies asfálticas urbanas utilizando chuva simulada

Abstract

The wash-off of pollutants from asphaltic surfaces by runoff is one of the main sources of water quality degradation in urban water bodies. However, little is known about the potential of these pollutants to be transported by runoff. In this regard, this research aims tocharacterize the runoff water and quantifying the mass of washed-off pollutants from asphaltic surfaces relating it with rainfall intensity and traffic load. Therefore, three streets with different traffic loads have been selected.in the city of Goiânia, Goias, Brazil. Over an asphaltic surface of 3 m2 two 15 minutes duration rainfall events were simulated (115 and 25mm/h) considered of high and low intensity. Water samples were collected every 3 minutes interval by means of a collecting system (frame, collecting tray and vacuuming system) and analyzed according to its contents of TSS, TDS, COD, conductivity, Cu, Cr, Pb, Cd, Zn, Fe and Mn. Rainfall and flowrate were measured by the volumetric method. Results show that all the analyzed parameters, except for Cr, have been detected in the runoff of all three studied areas. Generally, greater washed-off masses of Fe > Mn ≈ Zn > Pb ≈Cu > Cdwere found, listed in decreasing order of magnitude. Regards to the influence of rainfall, it has been noticed that the greater the rainfall intensity the greater the washed-off mass of solids and metals. However, no clear relationship has been found between the traffic load and the washed-off mass of metals