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Heavy metals in urban street surface sedimentsWarren, Robert Stephen January 1987 (has links)
A literature survey has been undertaken of the sources, levels and effects of heavy metal pollution in the urban street environment. Established techniques for the determination of heavy metal levels in urban dusts have been reviewed, and appropriate methods selected for use in the research project. Spatial and temporal variations of Cd, Cu, Pb and Zn in street dust have been investigated at a number sites. Metal loadings showed stronger spatial variation than concentrations with the greatest metal loadings occurring in the gutters and kerbsides. The results have been assessed in terms of surface type and condition, traffic loadings and antecedent weather conditions. The chemical associations of heavy metals in street dust, and their relationships to particle size have been investigated. Lead and Zn were associated mainly with carbonates and Fe-Mn oxides, whereas Cu is largely found in the organic fraction. Cadmium shows the greatest affinity for the exchangeable phase, and is therefore considered the most environmentally mobile metal studied. In addition to the studies mentioned above levels and chemical associations of heavy metals In school playground dust contaminated by paint flakes have been investigated. The levels of Pb were much higher than those previously reported. Exchangeable Pb concentrations represented a significant hazard to children playing in the area. In addition to the studies mentioned above levels and chemical associations of heavy metals In school playground dust contaminated by paint flakes have been investigated. The levels of Pb were much higher than those previously reported. Exchangeable Pb concentrations represented a significant hazard to children playing in the area. The final stage of the research project involved the operation of a sampling network to establish a mass balance for Cd, Cu, Pb and Zn within a residential urban street. Metal levels in atmospheric deposition, street sediments and runoff were monitored over an eight week period. Stormwater runoff was found to remove only a minor fraction of the metal deposited in the catchment during the sampling period.
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