SURVEY AND EVALUATION OF AQUATIC BRYOPHYTES IN THE FREDERICK COUNTY REGION TO DETERMINE THEIR POTENTIAL AS HEAVY METAL POLLUTION INDICATORS

Abstract

Aquatic bryophytes are common autotrophs in stream communities and may experience the effects of water pollutants sooner than aquatic organisms occupying higher trophic levels. As a result, aquatic bryophytes may be able to indicate potential water pollution problems prior to their affecting higher trophic levels. The ability of bryophytes to take up heavy metals has been extensively studied in Europe. The results of this research suggests that aquatic bryophytes have potential as indicator species for heavy metal contamination. The first goal of this study was to determine the most abundant, indigenous aquatic bryophyte species in Frederick County, MD. The second goal was to evaluate the ability of this bryophyte to accumulate various heavy metals. The third goal was to characterize the initial uptake rate of a single heavy metal (Cadmium (Cd)) by varying concentration levels as well as observe the rate of metal loss. Fontinalis dalecarlica was the most abundant indigenous species in Frederick County and the bryophyte showed an affinity for Cd, Cu, Pb and Zn but very little for Cr. Further investigation was conducted using Cd, which was reported as the heavy metal pollutant of most concern to the Chesapeake Bay from the Potomac River Basin. Various uptake rates were observed for cultures at 5, 10, 50 and 80 ppm Cd. The Hanes-Woolf Model for rate kinetics was utilized to calculate the maximum uptake velocity (Vmax) = .121 mg Cd/hr and Km, the substrate concentration at which 1/2 Vmax is reached 8.124 mg Cd/L. This study demonstrates that (1) F. dalecarlica can take up heavy metals and (2) accumulate Cd in its tissues and release it over time; therefore, the potential for F. dalecarlica to be used as a pollution indicator has been established.