Adsorption and Desorption of Naphthalene in Bioretention Cells

Naphthalene is a toxic contaminant commonly found in urban stormwater. Low impact development stormwater management practices such as bioretention cells are effective in reducing contaminant input into downstream. To this date, the transfer and transformation processes of typical urban runoff trace organic contaminants have not been characterized extensively; particularly in winter conditions. This study investigated the adsorption and desorption of naphthalene in bioretention cells at various temperatures and salinities. 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, and the adsorption of naphthalene was partially reversible under some conditions. 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 can store up to 80% of the inflowing naphthalene over short periods.M.A.S