The fate of acetone in an outdoor model stream to which nitrate was added as a nutrient supplement was determined. The stream, in southern Mississippi, U.S.A. was 234 m long. Water was supplied to the stream by an artesian well at about 1.21 s−1, resulting in a mean water velocity of about 0.5 m min−1. Acetone was injected continuously for 26 days resulting in concentrations of 20–40 mg l−1. A nitrate solution was injected for 21 days resulting in an instream concentration of about 1.7 mg l−1 at the upstream end of the stream. Rhodamine-WT dye was used to determine the travel time and dispersion characteristics of the stream, and t-butyl alcohol was used to determine the volatilization characteristics.
Volatilization controlled the fate of acetone in the model stream. The lack of substantial bacterial degradation of acetone was contrary to expectations based on the results of laboratory degradation studies using model stream water enriched with nitrate. A possible explanation for the lack of significant degradation in the model stream may be the limited 6-h residence time of the acetone in the stream.
