Removal of Dissolved Copper and Zinc from Highway Runoff via Adsorption

Abstract

Dissolved copper and zinc are commonly observed in highway runoff at concentrations that have been shown to exert toxic effects on aquatic microbiota and macrobiota. Dissolved copper in particular has been shown to disrupt the olfactory nervous system of salmon species at concentrations as low as 3 μg/L. To reduce concentrations to below this threshold, treatment of highway runoff for the removal of copper and zinc is necessary. This study developed a column testing protocol that can be used to quickly and reliably evaluate adsorptive removal of dissolved heavy metals from highway runoff. The protocol is demonstrated in an evaluation of iron oxide, manganese oxide, crab shell, concrete, and bone meal media for removing dissolved copper and zinc as a function of runoff characteristics, including pH, ionic strength, alkalinity, and total organic carbon. The results indicate that iron oxide media in combination with crab shell or concrete media is the most effective adsorptive technique for the removal of copper and zinc from highway runoff, and confirm the efficacy of the proposed protocol.