Master of Science (MS)
Semester of Degree Completion
William A. Weiler
Exposure to trace heavy metals is being extensively studied in relation to their adverse and toxic effects on organisms. Processes affecting compartmentalization, biogeochemical cycling, and transport of trace metals in ecological systems must be elucidated if the impact of trace metal releases on biota are to be understood. Because elemental cycles are often closely linked to hydrologic processes, freshwater and marine systems serve as both vectors and sinks for trace metals in the environment. The regular addition of a heavy metal into an aquatic ecosystem will undoubtedly increase its persistance for availability to the existing biota. Once in the environment, the contaminant may be bioaccumulated so that the concentration within the tissues of an organism is greater than that in the environment. Biomagnification may result when a consumer further concentrates the contaminant with resulting increases in "body burden" at successive trophic levels.
The Charleston Side Channel Reservoir is a 346-acre impoundment in East Central Illinois which serves as the City of Charleston's water supply. Unfavorable taste and odor problems have occasionally occurred since construction in 1981, presumably due to algal blooms. The reservoir has been treated with one to two thousand pounds of copper sulfate each summer as an algicide. The impoundment is also used for sport fishing, prompting concern about possible copper accumulation in fish in that reservoir. Gizzard shad (Dorosoma cepedianum) were chosen for this study to determine relative condition and copper accumulation in whole body portions. This species is greatest in abundance in the reservoir and undergoes ontogenetic diet shifts, consuming detritus at some period in its life cycle. Copper is known to accumulate in detrital sediments, and thus should be directly passed on to detritivorous organisms.
Gizzard shad were collected from the Charleston Side Channel Reservoir and Lake Shelbyville and processed for physical and chemical measurements. Copper accumulation in whole fish portions was determined by atomic absorption spectroscopy. Measurements of whole body heavy metal content are critical to the study of biomagnification because predators consume entire prey, not selected organs. Furthermore, concentrations for whole organisms are required for investigations of trace metal compartmentalization and flux in populations and ecosystems.
No correlation between copper concentration and coefficient of condition for 0- and 1-yr fish from Charleston was observed. Although no significant difference was found for the 0-yr coefficient of condition between Charleston and Shelbyville shad, there was a highly significant difference between the coefficient of condition of 0- and 1-yr Charleston fish. It appears that 1-yr fish are in poorer condition than 0-yr fish. There was no significant difference in copper concentration between 0- and 1-yr fish from Charleston, but there is a significant difference in copper concentration for 0-yr fish from Shelbyville and Charleston. Shelbyville fish appear to have a greater copper concentration even though copper sulfate is not used in this impoundment. Since there is no correlation between coefficient of condition and copper concentration in Charleston gizzard shad, copper appears to have no deleterious effect in these fish at this time.
Christ, Mark T., "Copper Accumulation by Gizzard Shad (Dorosoma cepedianum) in the Charleston Side Channel Reservoir" (1990). Masters Theses. 2305.