Hydrological, Geochemical, and Ecological Characterization of Kesterson Reservoir: Annual Report, October 1, 1987-September 30, 1988

摘要

Over the last year the ecological studies have focused on two areas, the wet and dry zones. The studies reported here are the latest results from the Pond 5E experiment, which has now been terminated, and the terrestrial food chain study, which has also been terminated. Although most of the data for these two projects have been collected and analyzed, there remain the last collections (September) to be fully analyzed. Tentative conclusions from the Pond 5E experiment indicate that the decline in selenium has continued for most biota. The decline, which commenced soon after the introduction of low-selenium water, has not been a smooth decline. The initial logarithmic decline has shown a definite seasonal cycling with the winter values being higher than those of summer. Most species are still apparently not in equilibrium with the selenium in their environment. The sources of selenium in Pond 5E are new (from the approximately 1.0 ppB in the groundwater supply) or recycled selenium (from extraction of plants and animals). Thus a continued declining trend is apparent for most, but not all, species. The final data points will allow calculation of the depuration kinetics for the final stages. 56 refs., 58 figs., 23 tabs.