Sources of Polycyclic Aromatic Hydrocarbons in Urban Storm Water runoff in Tijuana, Mexico

Eight sites were sampled during seven rain events to quantify and identify the sources of polycyclic aromatic hydrocarbons in urban runoff in the city of Tijuana, Mexico. The total ?16 PAHs concentration rangedfrom 1113 to 4866 µg/Lin the sampled sites and thetotal suspended solid concentrations ranged from 7725 to 4413 µg/L. The high concentrations of total suspended solids were probably the result of the erosion of bare soil areas in the basin area of the sampling sites. The PAH concentration in urban runoff from industrial sites was not as high as expected in comparison to residential sites. The potential sources of PAH were identified using the diagnostic ratios between PAHs and PCA analysis. Vehicular exhaust emissions (diesel and gasoline) and used crankcase oil were the main contributors to PAHs in urban storm water runoff. Charcoal combustion, diesel oil andlubricant oil were also identified as contributors to PAHs.