THE CHARACTERIZATION AND TOXICITY OF SEDIMENT CONTAMINATED WITH ROAD RUNOFF

The extraction, fractionation and characterization of sediment contami nated with road runoff is described. Wet sediment was successfully ext racted with dichloromethane and the extract was separated into three i ncreasingly polar fractions using alumina-silica column chromatography . Each fraction was characterized by GC-MS, GC/MS/i.r. and i.r. spectr ophotometry. The first fraction (FA) contained aliphatic hydrocarbons, the second fraction (FB) contained 2-5-ring polycyclic aromatic hydro carbons (PAHs) and the third fraction (FC) contained substituted pheno ls and 4- and 5-ring PAHs. The toxicity of each fraction to Photobacte rium phosphoreum and Gammarus pulex was assessed. The FA fraction was the most toxic to P. phosphoreum and the FC fraction was the least tox ic. In contrast the FB fraction was the most toxic to G. pulex and the other two fractions were not toxic at the concentrations tested.