Assessing unrecorded organic pollution from agricultural, urban, and wooded lands

An investigation was conducted of the organic pollution for seven small New Jersey watersheds representing agricultural, urban, and wooded lands. The 5-day biochemical oxygen demand (BOD) was used as a main index of organic pollution. Data obtained for a 2·5 yr period indicate background BOD concentrations averaging from 0·5 to 2·0 mg l −1 in all streams, except that a value of 9·0 mg l −1 was obtained for a residential-commercial-industrial area. During or after rainstorms, the BOD loadings, in pounds per day per unit area, averagely became more than ten times as the background amount for all streams. No significant correlation was found between BOD concentration and flow rate, but good correlations were obtained between BOD loadings and flows. The seasonal pattern of BOD loading distribution was examined. Also the frequency distribution of BOD concentrations and loadings were obtained.