Rainfall and runoff quantity and quality were monitored for industrial, single-dwelling residential, multiple-dwelling residential, and commercial land-use catchments in Fresno, California, during 1981-82 and 1982-83 rain seasons. Storm-composite rainfall and discrete runoff samples were analyzed for physical, inorganic, organic, and biological constituents. Atmospheric dry-deposition- and street-surface particulate samples also were collected and analyzed. Except for the industrial catchment, highest runoff concentrations for most constituents occurred during initial storm runoff and then decreased throughout the remainder of the storm; constituent concentrations for the industrial catchment fluctuated greatly. Statistical testing of runoff-quality data showed higher concentration for most constituents for the industrial catchment. Lead showed lower concentrations for the industrial catchment than for the other three catchments. Event mean concentration (EMC) for most constituents for all but the industrial catchment were highest for the first two or three storms of the rain season after which they became almost constant; the industrial constituent EMC 's generally did not show any pattern. The organophosphorus compounds, parathion, diazinon, and malathion were the most prevalent pesticides detected in rainfall. Other pesticides detected in rainfall included chlordane, lindane, methoxychlor, endosulfan, and 2 ,4-D. Of these, only methoxychlor and endosulfan were not consistently detected in the runoff. (USGS)
