Abstract
The concentrations and the amount of cumulative release of heavy metals (Zn, Cu, Cd, Cr, and Pb) in contaminated sediments collected from combined sewer system were investigated in order to provide a complete overview of the key variables affecting the heavy metals release from storm sewer sediments. The heavy metals release rates were affected to a much greater extent in the low pH (4–7) condition than in high pH (8–10) condition. At higher temperature (30–35°C) the release rates of metals were increased more rapidly than at low temperature. The release of Zn, Cu, Cr, and Pb appeared to increase under the aerobic condition during the first 150 min and then the concentration kept stable. Moreover, the adsorption of these metals and the release of Cd occurred in the anaerobic condition. The flow rate significantly affected the release amount of Zn, Pb, and Cr, while it slightly affected the concentration of Cu and Cd. This study reflects that any change of pH, temperature, dissolved oxygen, and flow rate of overlying water all cause the different variations of the concentrations of heavy metals.
Highlights
Combined sewer overflows (CSOs) are major sources of intermittent pollution affecting the receiving waters in the natural water areas as well as in many other urban areas serviced by combined sewers [1]
The objective of this study is to evaluate the influence of the pH, temperature, dissolved oxygen, and flow rate of overlying water on the release of heavy metals from storm sewer sediments
Different studies based on combined sewer sediments have shown that heavy metals with different speciations are generally associated with sewer water [17, 18]
Summary
Combined sewer overflows (CSOs) are major sources of intermittent pollution affecting the receiving waters in the natural water areas as well as in many other urban areas serviced by combined sewers [1]. Large volumes of water, charged with high concentrations of sediments, suspended solids, and dissolved and particulate-associated contaminants, such as metals, pesticides, polycyclic aromatic hydrocarbons, and nutrients, are released from the sewer system into the receiving water [6, 7]. The fate (speciation) of the metal released from sediments is affected by the overlying water condition, in particular the pH, salinity, dissolved oxygen concentration, and amount of suspended solids [14]. It had been found that the physical disturbance of sediments released metals more rapidly than biological disturbance [15]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
