Transport of polycyclic aromatic hydrocarbons and pesticides during snowmelt within an urban watershed

► Strong melt events correlate with elevated concentrations of particle-bound PAHs in river water. ► The PAH flux at the onset of melting exceeds the background chemical flux by three orders of magnitude. ► The pesticides lindane and chlorothalonil also tend to be released early during melting. ► Concentrations of both substances are low and likely reflect regional atmospheric background.