ASSESSMENT OF WATER QUALITY OF THE BIG BONE LICK SALT SPRINGS, KENTUCKY, USA

Big Bone Lick (BBL) State Park, commonly referred to as the birthplace of modern vertebrate paleontology is located approximately 30 miles Southwest of Cincinnati. Paleontological discoveries at the park dates back to the early 18^th century. Saltwater brines discharges to the surface at the Big Bone Creek valley through fault planes, joints and fractures in the bedrock. Literature suggests that these brines originate in Middle Ordovician St. Peter Sandstone located around 200 m below present-day land surface. Despite the paleontological significance of the site, hydrogeochemical conditions of these salt springs are poorly studied. Purpose of this research is to analyze the temporal variation of water quality at the BBL. Multiple water quality parameters were measured biweekly from late July to September at the BBL salt springs. Samples were also collected to measure the concentration of common and heavy metals in the lab. Total dissolved solids (TDS) vary 9000 to 2689 mg/L with values equivalent to brackish water. Measured TDS values vary widely with the local climatic conditions, with lower conductivity and TDS values reported following storm events. The pH and Eh values of the water vary from 8.5 to 8.07 and 0.025 to 0.16 mV respectively, representing reducing-basic conditions. Major anions concentration (Cl^-, CO₃^-2 and SO₄^-2) suggest a chloride dominated hydrogeochemical facies, characteristic of deep-seated brines. Trace metal analysis revealed, elevated Zn and Cu concentrations from 33.4 to 34.9 ppm and 8.6 to 10.2 ppm, respectively. These values exceed the EPA recommended Maximum Contaminant Levels. Hence further research need to be conducted at the site to test the possibility of BBL salt springs contaminating the Big Bone Creek and the Ohio River.