The characterization and toxicity of sediment contaminated with road runoff

The extraction, fractionation and characterization of sediment contaminated with road runoff is described. Wet sediment was successfully extracted with dichloromethane and the extract was separated into three increasingly polar fractions using alumina-silica column chromatography. Each fraction was characterized by GC---MS, GC/MS/i.r. and i.r. spectrophotometry. The first fraction (FA) contained aliphatic hydrocarbons, the second fraction (FB) contained 2–5-ring polycyclic aromatic hydrocarbons (PAHs) and the third fraction (FC) contained substituted phenols and 4- and 5-ring PAHs. The toxicity of each fraction to Photobacterium phosphoreum and Gammarus pulex was assessed. The FA fraction was the most toxic to P. phosphoreum and the FC fraction was the least toxic. In contrast the FB fraction was the most toxic to G. pulex and the other two fractions were not toxic at the concentrations tested.