DRIP WATER CHEMISTRY FROM DIAMOND CAVERNS,KY; PRELIMINARY RESULTS

This study focuses on spatial and temporal variations in the chemistry of cave drip waters collected from Diamond Caverns, a tourist cave located near Mammoth Cave National Park, KY. Samples are collected from fifteen sample sites extending approximately 0.5 miles from the mouth of the cave. Goals include establishing a base chemical composition for drip waters, identifying outlier compositions, and comparing these data to both external (above-ground) and cave interior environmental variables. Spatial parameters include CO2 levels and electrical conductivity measured in the caverns, ground water flow, and external environmental conditions such as proximity to pavement and agricultural areas. Temporal parameters include seasonal fluctuations (e.g. precipitation, temperature) and the impacts of seasonal tourism on cave environment.

The 15 sample sites are along or adjacent to the tourist trail throughout the cave. The majority of drips come off the end of a speleothem, with the exception of one site where the drip emanates from a crack in the cave ceiling. Sample collections are scheduled approximately every 2-3 weeks. During collection CO2 levels, temperature, rate of flow (drips/minute), and time are recorded at each site. Samples accumulate in bottles in fixed positions below drips until a minimum of 300 mL (required for lab tests) is collected. Those samples that do not meet the 300 mL requirement are left until they have accumulated the required amount. After collection, samples are transported to the WKU WATERs Facility, where approximately 50 mL of each sample is preserved with nitric acid to prevent microbial growth and stored in amber vials in a refrigerator. Titrations are performed at the lab using the remainder of the sample volume. The alkali content of each sample is recorded along with the CO2, temperature, and rate of flow measurements. After every 8-10 collections, archived samples are analyzed at the ERTL facility at the University of Kentucky, using OES-ICP-MS. The suite of elements analyzed during each session are Ca, Mg, K, Na, Ba, Sr, Mn, Fe, Ni, Co, Cu, Si, Al, and Zn. Compositional variations (including elemental ratios) both at individual sites and along the collection traverse were identified and compared with initial measurements from within the cave to clarify potential influences.