Change in methylene blue active substances and chloride levels in streams in Suffolk County, New York, 1961-1976

Since 1961, concentrations of methylene blue active substances and chloride were measured in samples collected at 67 sampling stations on 44 streams in Suffolk County, Long Island, New York. Changes in the concentrations of these constituents and calculated chloride/methylene blue active substances ratios are reported. Although many factors--the 1962 to 1966 drought, urbanization, change in detergent formulation, and the 1971 Suffolk County detergent ban--make specific interpretation of the data difficult, it appears that the quality of water in streams and, consequently, that part of the upper glacial aquifer supplying water to the streams, is improving in terms of the concentration of methylene blue active substances.