Hydrocarbons in urban runoff

Runoff from 15 watersheds in the San Francisco Bay area are sampled over a 2 year period and analyzed for hydrocarbons. Both gravimetric analyses and high resolution gas capillary chromatography are performed. It is found that land uses with high commercial/industrial activity have much greater aliphatic hydrocarbon emissions than non-commercial areas. A relationship between commercial land use and the anthropogenic aliphatic hydrocarbon fraction is found. The ratio of total extractable organics carbons is found to vary with land use, with a ratio of six or more indicating significant commercial/industrial activity. Aromatic hydrocarbons, including polynuclear aromatics are also found, but in smaller concentrations that aliphatics.