Adsorption and desorption of naphthalene in bioretention cells under cold climate conditions

Abstract

Naphthalene, originating from anthropogenic activities, is a toxic contaminant commonly found in urban stormwater runoff. This study investigated the adsorption and desorption potential of naphthalene in a bioretention cell soil at various temperatures and salinities representative of cold-climate winter conditions. In all experiments, more than 70% of the initially added naphthalene was adsorbed on the bioretention soil at equilibrium. Temperature and salinity showed little but inconsistent effects on the adsorption of naphthalene, and the adsorption of naphthalene was partially reversible under some conditions, e.g., at higher temperature. Despite its reversibility, naphthalene desorption may allow for the regeneration of the sorption capacity of the soil media, and transformation processes to take place. Overall, these results suggest that bioretention cells are able to temporarily retain a large portion of the inflowing naphthalene over short periods.