In the karstic Ozark Plateau region of Missouri and Arkansas, numerous springs are used as the water supply for fish hatcheries. In addition, streams fed by spring water are good habitat for many non-game fish species; also, two species of endangered cavefish have been found to live within the karstic aquifers. At relatively low concentrations, the naturally occurring estrogen compounds (17-B estradiol (E2 ) and estrone (E1 ), which are discharged from livestock and sewage wastes, lead to feminization of fish, and at somewhat higher concentrations to failure of vital organs and death. Thus, contamination of the groundwater and spring waters by wastes that contain E2 ) and E1 ) could adversely impact the health of game fish, non-game fish, and cavefish.
Our first goal is to determine the geographic distribution and the extent to which the spring waters of the Ozark Plateau are contaminated with E2 and E1 by establishing a sampling and storage protocol for measuring their concentration in spring waters using ELISA technique. Preliminary sampling at four springs within the Springfield Plateau have found E2 concentrations ranging from 10 to 65 ng/L. These concentrations are within the range having a deleterious effects on biota (50ng/L). We have not yet found a spring that does not have E2 contamination.
This data will be presented to State level agencies. Also, by determining the distribution and extent of the contamination, we will be able to focus subsequent research on six springs (the three that exhibit the lowest concentrations of E2 and E1 and the three that exhibit the highest concentrations of E2 and E1).
Once the springs are selected, we will determine the mass flux of E2 and E1 discharged from the karstic aquifer by measuring discharge by using standard surface water gauging techniques and stage recorders. Since the concentrations of E2 and E1 can be reliably determined down to 20 ng/L, the mass flux of E2 and E1 out of the basins can be determined. These basins are fed by large losing streams that supply 90% of the discharge. For each basin, the losing stream will be located and gauged. Errors on mass flux calculations can be minimized by careful stream gauging, careful analytical work, and by making sure all losing streams (if these are multiple losing streams) are gauged.
Because the cavefish live in the aquifer and the sampling measures discharge from the aquifer, the cavefish might be exposed to higher concentrations due to degradation in the aquifer. Our third goal is to determine whether E2 and E1 are degraded at typical spring water conditions (chemical and physical) and to determine the concentration and dosages experienced by the cavefish.