Abstract Indiana Limestone is one of the most used and versatile building stones in the USA. It is a uniform, carbonate grainstone formed during the Mississippian Subperiod of the Carbonifereous. The stone has excellent physical properties, good workability, fire resistance, durability, sustainability, reserves sufficient for hundreds of years, remarkable history, and is available in pleasing colours and textures. Indiana Limestone is used extensively for important buildings, homes, or carved as accents and sculptures, as well as other uses. At one time it was estimated that 60–80% of important US stone buildings were built with Indiana Limestone. This stone has been used for significant, even iconic buildings such as the Empire State Building and the Yankee Stadium, the Pentagon and many other government buildings, even religious structures such as the National Cathedral in Washington, DC, notable houses such as the Biltmore House in North Carolina, many Chicago landmarks, plus libraries, research centres, academic buildings and museums, across the USA. Sculptures throughout the USA and other countries are made of Indiana Limestone. The stone has good sustainability and is incorporated into the very culture of the state of Indiana and America. Indiana Limestone merits designation as a Global Heritage Stone Resource.

The Spring Mill Lake watershed is located in the Mitchell Plateau, a karst area that developed on Mississippian carbonates in southern Indiana. Spring Mill Lake is a reservoir built in the late 1930s and is located in Spring Mill State Park. Within the park, groundwater from subsurface conduits issues as natural springs and then flows in surface streams to the lake. From 1998 to 2002, surface and subsurface hydrology and water quality were investigated to determine the types and sources of potential contaminants entering the lake. Water samples collected during base flow and a February 2000 storm event were analyzed for selected cations, anions, trace elements, selected U.S. Environmental Protection Agency (EPA) primary and secondary drinking-water contaminants, nitrogen isotopes, suspended solids, Escherichia coli , and pesticides. All of the water samples met the EPA drinking-water standards for inorganic constituents, except those collected at five sites in August 1999 during a drought. Nitrate nitrogen (NO 3 -N) concentrations were highest during base-flow conditions and displayed a dilutional trend during peak-flow periods. The NO 3 -N concentrations in water samples collected during the 2001 spring fertilizer applications tended to increase from early to late spring. All of the δ 15 N values were low, which is indicative of either an inorganic source or soil organic matter. Storm discharge contained increased concentrations of total suspended solids; thus, storms are responsible for most of the sediment accumulation in the lake. E. coli levels in 24% of the samples analyzed contained a most probable number (MPN) greater than 235/100 mL, which is the maximum acceptable level set for recreational waters in Indiana. E. coli does appear to be a potential health risk, particularly at Rubble spring. The sources of E. coli found at this spring may include barnyard runoff from a horse barn or wastes from a wastewater treatment facility. The pesticides atrazine, metolachlor, acetochlor, and simazine were detected during the spring of 2001. Atrazine, metolachlor, ace-tochlor, and simazine are used to suppress weeds during corn and soybean production. Additional sources of atrazine and simazine may result from application to right-of-ways, orchards, and managed forest areas.