This report summarizes findings detailed in Reports No. 4 and 5 plus the work of Zawlocki on trace organics in highway runoff. Several hundred compounds tentatively identified by GC-MS were grouped into nine categories, which were not mutually exclusive. Major components of these categories were petroleum products used by vehicles and incompletely combusted hydrocarbons. The concentrations of these trace organics groups were low compared to criteria proposed for protection of aquatic life.