Schmidt, Torsten Claus; Haderlein, Stefan B.; Pfister, R.; Forster, R.:

Occurrence and fate modeling of MTBE and BTEX compounds in a Swiss Lake used as drinking water supply

In: Water Research, Jg. 38 (2004), S. 1520-1529
Zeitschriftenaufsatz / Fach: Chemie
Emissions of fuel components from boating use on multiple-use lakes and reservoirs are of high concern with regard to the drinking water supply from such water bodies. We report results of a detailed study on the occurrence, sources   and fate of aromatic hydrocarbons and methyl tert-butyl ether (MTBE) in a typical holomictic lake, Lake Zurich, that   supplies drinking water for the largest Swiss city. Emphasis of the investigation was on the fuel oxygenate MTBE,   which was found in concentrations up to 1.4 mg/L in the epilimnion and up to 0.05 mg/L in the hypolimnion of the lake.   The concentration difference was due to the strati.cation of the lake during the boating season with very limited water   exchange across the thermocline. MTBE and BTEX nearly completely volatilized before vertical lake mixing occurred   in winter. Spatial and temporal variations of MTBE concentrations in the lake were observed and successfully predicted   using two complementary box models (MASAS Light and Aquasim). The drinking water supply from holomictic lakes   is not at risk for the scenarios studied if water is extracted from well below the thermocline. Since emissions of unburned   gasoline into such water bodies are caused predominantly by boating activities, restrictions of highly emitting twostroke   engines could substantially reduce the MTBE and BTEX load of the epilimnion during the boating season.