Download Current Seasonal Limnology of the Berkeley Pit-Lake

CURRENT SEASONAL LIMNOLOGY OF THE BERKELEY PIT LAKE
Jim Jonas
9852 Independence Street, Westminster, CO 80021; Phone: (303) 421-7527, E-mail:
[email protected].
The Berkeley Pit Lake was sampled during two seasons, fall 1997 and spring
1998, from the surface to the bottom. Various parameters were measured to determine
what effect the seasons had on the water chemistry. It appears that a seasonal turnover
did occur between the fall and the spring sampling; however, the depth of mixing due to
turnover could not be established. Trends were observed which suggested the microbial
activity was altering the iron speciation at depth, and subsequently masking the extent of
mixing. Various trace metals were removed from the surface water by either coprecipitation with schwertmannite or adsorption. Optical microscopy, scanning electron
microscopy, and geochemical modeling were performed to determine the composition of
the precipitates formed in the surface water. This work is being performed under the
Mine Waste Technology Program, funded by the U.S. Environmental Protection Agency
(EPA) and jointly administered by the EPA and the U.S. Department of Energy, Contract
Number DE-AC22-96EW96405.
Key words: water chemistry, seasonal turnover, EPA