Groundwater Quality in Watersheds of the Kentucky River, Salt River, Licking River, Big Sandy River, Little Sandy River, And

1 Groundwater Quality in Watersheds of the Kentucky River, Salt River, Licking River, Big Sandy River, Little Sandy River, and Tygarts Creek (Kentucky Basin Management Units 1, 2, and 5) R. Stephen Fisher1 Bart Davidson1 Peter T. Goodmann2

Abstract The Kentucky Geological Survey, University of Kentucky, and the Kentucky Division of Water (of the Kentucky Environmental and Public Protection Cabinet) are evaluating groundwater quality throughout the commonwealth to determine regional conditions, assess impacts of nonpoint-source pollutants, establish a basis for detecting changes, and provide essential information for environmental-protection and resource-management decisions. These evaluations are being conducted in stages. Under the Kentucky Watershed management Framework, Kentucky’s 12 major river basins and tributaries of the Ohio River were grouped into ﬁ ve basin management units (BMU’s). A previous report summarized and evaluated groundwater quality in BMU 3 (watersheds of the Upper Cumberland River, Lower Cumberland River, Tennessee River, the Jackson Purchase Region, and adjacent Ohio River tributaries). That report is available on the KGS Web site (www.uky.edu/KGS/water/RI_15/). This report summarizes results of analyses of groundwater samples from wells and springs in BMU 1 (Kentucky River watershed and adjacent Ohio River tributaries), BMU 2 (Salt River and Licking River watersheds and adjacent Ohio River tributaries), and BMU 5 (Big Sandy River, Little Sandy River, and Tygarts Creek watersheds, and adjacent Ohio River tributaries). Analytical results for selected water properties, major and minor inorganic ions, metals, nutrients, pesticides, and volatile organic chemicals were retrieved from the Kentucky Groundwater Data Repository. The repository is maintained by the Kentucky Geological Survey and contains reports received from the Division of Water’s Ambient Groundwater Monitoring Program as well as data from investigations by the U.S. Geological Survey, U.S. Environmental Protection Agency, U.S. Department of Energy, Kentucky Geological Survey, Kentucky Division of Pesticide Regu- lation, and other agencies. The Kentucky Division of Water provided water-quality standards. Statistics such as the number of measurements reported, the number of sites sampled, quartile concentration values, and the number of sites at which water-quality standards were met or exceeded are used to summarize the data. Maps show sampled locations and sites where water-quality standards were met or exceeded. Cumulative data plots are used to show concentration distributions

1Kentucky Geological Survey 2Kentucky Division of Water 2 Abstract in each basin management unit. Box-and-whisker diagrams compare values between physiographic regions, major watersheds, wells and springs, and total versus dissolved metal concentrations. Plots of analyte concentrations versus well depth compare groundwater quality in shallow, intermediate, and deep groundwater ﬂ ow systems. Table A1 summarizes the ﬁ ndings. General water-quality properties, inorganic anions, and metals are pri- marily controlled by natural factors such as bedrock lithology. Some exceptionally high values of conductance, hardness, chloride, and sulfate may be affected by nearby oil and gas production or improperly sealed oil and gas wells, leaking waste-disposal systems, or other man-made factors, and some exceptionally low pH values probably result from acid mine drainage. Nitrate concentrations show a strong contribution from agricultural and waste-disposal practices, whereas orthophosphate and total phosphorus concentrations are largely determined

Table A1. Summary of evidence for nonpoint-source impacts on groundwater quality in basin management units 1, 2, and 5.

No Strong Evidence for Evidence for Some Evidence for Deﬁ nite Parameter Widespread Nonpoint- Nonpoint-Source Impact Nonpoint-Source Impact Source Impact

Conductance X Hardness X Water pH X Properties Total dissolved solids X Total suspended solids X

Chloride X Inorganic Sulfate X Ions Fluoride X

Arsenic X Barium X Metals Iron X Manganese X Mercury X

Ammonia-nitrogen X Nitrate-nitrogen X Nutrients Nitrite-nitrogen X Orthophosphate X Total phosphorus X

2,4-D X Alachlor X Pesticides Atrazine X Cyanazine X Metolachlor X Simazine X

Benzene X Volatile Ethylbenzene X Organic Toluene X Compounds Xylenes X MTBE X

1 Methyl tertiary-butyl ether Previous Investigations 3 by the chemical composition of limestone bedrock and coal strata. Synthetic organic chemicals such as pesticides and reﬁ ned volatile organic compounds do not occur naturally in groundwater. Although these chemicals rarely exceed water-quality criteria in the project area, the detection of these man-made chemicals in springs and shallow wells indicates there has been some degradation of groundwater quality. Monitoring of these synthetic, potentially health-threatening chemicals should continue, and efforts to protect the groundwater resources from them should be a priority for the commonwealth of Kentucky.

tors make replacing groundwater with surface-water Introduction supplies expensive or impractical in rural areas, and Purpose because some cities along the Ohio River are turning Evaluating groundwater quality is essential for to groundwater from alluvial deposits for urban water determining its suitability for various uses and the supplies. An estimated 400,000 Kentuckians will still sources of dissolved chemicals, and because regional depend on private, domestic water supplies in the year groundwater quality provides a sensitive indicator of 2020 (Kentucky Geological Survey, 1999). the general condition of the natural environment. This Both natural and man-made processes affect report summarizes groundwater quality in the north- groundwater quality. The major natural processes that eastern part of Kentucky (watersheds of the Kentucky contribute cations, anions, metals, nutrients, and sedi- River, Salt River, Licking River, Big Sandy River, Little ment to groundwater are dissolution of atmospheric Sandy River, and Tygarts Creek, and Ohio River tribu- gases as rain falls through the atmosphere, dissolution taries adjacent to those watersheds). Similar reports on of soil particles and physical transport of chemicals groundwater quality in the southwestern part of Ken- and sediment as rainfall fl ows across the land surface, tucky were previously completed (Fisher and others, dissolution of soil gases and reactions with inorganic 2004). and organic material in the soil zone above the water table, and reactions with gases, minerals, and organic Goals material beneath the water table. The goals of this report are to summarize regional Groundwater quality is also affected by human values for a group of groundwater-quality parameters activities that contribute synthetic organic chemicals and to determine whether nonpoint-source chemicals such as pesticides, fertilizers, and volatile organic com- have affected groundwater systems. The results identi- pounds, as well as cations, anions, metals, nutrients, fy natural and anomalous concentrations of dissolved and sediment, to the water system. Nearly all activities chemicals, show areas where nonpoint-source chemi- that threaten surface waters and aquatic ecosystems cals have entered the groundwater system and imple- also endanger groundwater systems. Agriculture, con- mentation of best management practices are needed, fi ned animal-feeding operations, forestry, mining, oil provide information for Kentucky Division of Water and gas production, waste disposal, and urban storm- watershed assessment reports, provide groundwater- water runoff can deliver pesticides, fertilizers, nutri- quality data to the DOW’s Groundwater Protection ents, metals, and hydrocarbons to groundwater. program, help the DOW’s Wellhead Protection program set priorities to protect areas and activities, and Previous Investigations provide critical information for long-term protection Numerous reports covering the study area or and management of water resources. nearby areas describe the hydrology, groundwater resources, and general water quality of the study area. Background Few address the issue of nonpoint-source contamina- Evaluating groundwater quality is particularly tion, however. In the 1960’s and early 1970’s, the U.S. important in Kentucky because groundwater use is Geological Survey published reconnaissance studies extensive and will continue to be so. The 1990 cen- of the geology, groundwater supplies, and general sus data and recent DOW estimates indicate that ap- groundwater quality in Kentucky. These reports in- proximately 60 percent of public water-supply compa- clude a Hydrologic Atlas series, which was made in nies use groundwater as a sole or contributing water conjunction with the Kentucky Geological Survey; source, more than 25 percent of the population uses each atlas covers from two to 10 counties across the groundwater for domestic purposes, and more than state (except in the Jackson Purchase area, which had 226 million gallons of groundwater are consumed dai- coverage for each 7.5-minute quadrangle). Each atlas ly by individuals, municipalities, utilities, businesses, includes three sheets showing geology, lithology, and and farms. Groundwater will continue to be important availability of groundwater. The atlases have been to Kentuckians because economic and logistical fac- 4 Project Area scanned and are currently available online (www.uky. The project area includes six of Kentucky’s phys- edu/KGS/water/library/USGSHA.html). The Ken- iographic regions: Eastern Kentucky Coal Field, the tucky Geological Survey developed a series of county Knobs, Eastern and Western Pennyroyal, Outer Blue- groundwater-resource reports based on the USGS Hy- grass, and Inner Bluegrass (Fig. 1). Each region is dis- drologic Atlases. Each report (www.uky.edu/KGS/ tinguished by unique bedrock type, topography, and water/library/webintro.html) contains from 16 to 31 soil types (McDowell, 1986; Newell, 1986). This frame- pages of information on geology, hydrogeologic char- work is important to understanding groundwater acteristics of aquifers, available water supplies, and quality because it has a controlling effect on the natural availability of groundwater for public consumption. occurrences of major and minor inorganic solutes and Older but more comprehensive groundwater-resource metals. It also strongly infl uences land use, urban and reports related to this study area cover the Bluegrass commercial development, and the potential use of nu- Region (Hendrickson and Krieger, 1964; Faust, 1977), trients, pesticides, and volatile organic compounds. Eastern Kentucky Coal Field (Price and others, 1962), The Eastern Kentucky Coal Field is characterized and the Mississippian Plateau Region (Brown and by deeply incised sandstone, shale, and coal strata that Lambert, 1963), herein referred to as the Eastern and are essentially horizontal throughout most of the area Western Pennyroyal Regions. These reports consid- but are steeply inclined to nearly vertical along the ered major and minor inorganic ions and nitrate; other Pine Mountain Overthrust Fault in southeastern Ken- nutrients, metals, and synthetic organic chemicals were tucky. Steep hillsides separate narrow, fl at river valleys not considered. Sprinkle and others (1983) summarized from sharp, sinuous mountain crests. Valley slopes are general groundwater quality throughout Kentucky. typically fractured and covered by rock fragments and The Kentucky Geological Survey (1999) summarized weathered material; soils are generally thin except in groundwater supply and general groundwater qual- river valleys (Newell, 1986). ity throughout the state for the Groundwater Resource The Eastern and Western Pennyroyal Regions Development Commission (kgsweb.uky.edu/down- consist mainly of thick, horizontally bedded limestone load/wrs/GWTASK1.PDF). Carey and others (1993) with minor thin shales. The Pennyroyal surface is surveyed selected groundwater-quality parameters, characterized by karst features such as sinkholes and including nutrients and pesticides, in private ground- springs, connected by underground solution channels water supplies. and caves. Soils are composed of insoluble residue that Two other sources of largely uninterpreted ana- remains as the carbonate rocks weather. lytical data contributed signifi cantly to the database The Knobs Region is a narrow belt separating the used here. Faust and others (1980) summarized the Eastern Pennyroyal Region from the Outer Bluegrass results of cooperative groundwater investigations in- Region. It is characterized by conical, fl at-topped hills volving KGS and other State, Federal, and local agen- composed mostly of shale and siltstone, topped by cies. The National Uranium Resource Evaluation pro- more resistant cap rock. Soils are thin except where the gram provided a large source of analyses of groundwa- lower slopes of knobs merge with alluvium in valley ter, surface water, and stream sediments (Smith, 2001). bottoms. Digital records from both these reports are stored in The Inner and Outer Bluegrass Regions are gen- the Kentucky Groundwater Data Repository and were tly rolling to relatively fl at lowlands, underlain with used in this report. interbedded limestones and shales. The regions dis- DOW interpreted the results of expanded ground- play well-developed karst features such as sinkholes, water monitoring in BMU 2 as a contract report (Webb springs, underground streams, and caves. Soils in the and others, 2003). The data used in that report are in- Inner Bluegrass are generally thick and phosphatic, cluded in the larger data sets used here. whereas soils in the Outer Bluegrass range from thick and rich over limestones to thin and clayey over shales Project Area (Newell, 1986). The DOW Watershed Management Framework (Kentucky Division of Water, 1997) grouped Ken- Basin Management Unit 1: tucky’s major river basins into fi ve basin manage- Kentucky River Watershed ment units (Fig. 1). This project covers watersheds of The Kentucky River watershed (basin manage- the Kentucky River (BMU 1), Salt and Licking Rivers ment unit 1) includes the Inner and Outer Bluegrass, (BMU 2), and the Big Sandy River, Little Sandy River, Knobs, Eastern Pennyroyal, and Eastern Kentucky and Tygarts Creek (BMU 5). Coal Field Regions, and covers an area of about 6,975 mi2 (Fig. 1). The Kentucky River originates in the Basin Management Unit 1: Kentucky River Watershed 5 � � � � � �� Figure 1. Locations of major river watersheds, physiographic regions, and basin management units. This study summarizes groundwater-quality data management units 1, 2, and 5. from basin 6 Basin Management Unit 2: Salt River and Licking River Watersheds mountains of the Eastern Kentucky Coal Field and ban land account for the remainder (Kentucky Division fl ows northwest through the Knobs and the Outer and of Water, 2001). The major nonpoint-source threats are Inner Bluegrass Regions to join the Ohio River near fertilizers, pesticides, animal wastes, mine drainage, Carrollton in Carroll County. The total length of the runoff from mine spoil, leaking septic systems, and ur- river in the basin is approximately 405 mi. The main ban stormwater runoff. stem of the Kentucky River extends approximately BMU 2 includes all or parts of Anderson, Bath, 255 mi through 14 locks and dams. Boone, Bourbon, Boyle, Bracken, Breathitt, Breckin- Land uses and nonpoint-source chemical threats ridge, Bullitt, Campbell, Carroll, Carter, Casey, Clark, to groundwater quality in BMU 1 include oil and gas Elliott, Fayette, Fleming, Floyd, Gallatin, Grant, Green, production; active and abandoned coal mines; leaking Greenup, Hardin, Harrison, Henry, Jefferson, Johnson, sewage-disposal systems; straight pipes (household Kenton, Knott, Larue, Lewis, Lincoln, Magoffi n, Mar- sewage dumped directly into streams or rivers); de- ion, Mason, Meade, Menifee, Mercer, Montgomery, forested areas in the Eastern Kentucky Coal Field; and Morgan, Nelson, Nicholas, Oldham, Pendleton, Pow- farm land, urban centers, and confi ned animal-feed- ell, Robertson, Rowan, Scott, Shelby, Spencer, Taylor, ing operations (Kentucky Division of Water, 2000). Trimble, Washington, and Wolfe Counties. Groundwater is particularly vulnerable to nonpoint- source contamination in the karst regions of the Blue- Basin Management Unit 5: Big grass because of the well-developed network of sink- Sandy River, Little Sandy River, and holes, caves, and springs. BMU 1 includes all or parts of Anderson, Bell, Tygarts Creek Watersheds Boone, Bourbon, Boyle, Breathitt, Carroll, Casey, Basin management unit 5 includes watersheds Clark, Clay, Estill, Fayette, Floyd, Franklin, Gallatin, of the Big Sandy and Little Sandy Rivers and Tygarts Garrard, Grant, Harlan, Harrison, Henry, Jackson, Creek. This basin covers approximately 4,610 mi2 in Jessamine, Kenton, Knott, Knox, Laurel, Lee, Leslie, the Eastern Kentucky Coal Field. The Big Sandy River Letcher, Lincoln, Madison, Magoffi n, Menifee, Mercer, forms the northeastern boundary between Kentucky Montgomery, Morgan, Owen, Owsley, Perry, Pike, and West Virginia, and fl ows northwest to Boyd Coun- Powell, Rockcastle, Scott, Shelby, Trimble, Wolfe, and ty, where it joins the Ohio River near Catlettsburg. The Woodford Counties. Little Sandy River fl ows northeast in the northern half of BMU 5, and joins the Ohio River near the town of Basin Management Unit 2: Salt Greenup in Greenup County. Tygarts Creek is east of and roughly parallel to the Little Sandy River, and River and Licking River Watersheds fl ows into the Ohio River in northern Greenup Coun- Basin management unit 2 consists of the Licking ty. River and Salt River watersheds and adjacent Ohio Land uses and nonpoint-source chemical threats River tributaries. The Licking River has headwaters to groundwater quality in BMU 5 include oil and gas in the mountains of Magoffi n County in the Eastern production, active and abandoned coal mines, leaking Kentucky Coal Field and fl ows northwest toward the sewage-disposal systems, deforested areas in the East- Ohio River. The Licking River fl ows through the East- ern Kentucky Coal Field, and confi ned animal-feeding ern Pennyroyal and Knobs Regions into the Outer and operations (Kentucky Division of Water, 2000). The Inner Bluegrass Regions and enters the Ohio River major nonpoint-source threats are mine drainage, run- between Newport and Covington. The Licking River 2 off from mine spoil, leaking septic systems, straight Basin drains approximately 3,710 mi , and provides a pipes, fertilizers, pesticides, and animal wastes. source of drinking water for nearly 80 percent of the BMU 5 includes all or parts of Boyd, Carter, El- population in the basin. liott, Floyd, Greenup, Johnson, Knott, Lawrence, Although the Salt River Basin is west of the Ken- Letcher, Lewis, Magoffi n, Martin, Morgan, Pike, and tucky River Basin, it is also included in BMU 2. This Rowan Counties. basin drains approximately 4,155 mi2. The Salt River itself is nearly 150 mi long and fl ows northwest, emp- Hydrogeologic Unit Codes tying into the Ohio River near West Point in northern The U.S. Geological Survey has assigned Hydro- Hardin County in the Fort Knox Military Reservation. logic Unit Codes to watersheds to identify regions, Land uses and nonpoint-source threats in BMU 2 subregions, accounting units, and cataloging units are varied. Agricultural land accounts for approxi- (U.S. Geological Survey, 1988). The HUC designations mately 57 percent of the region; forest land accounts of watersheds in BMU’s 1, 2, and 5 are listed in Tables for approximately 30 percent, and residential and ur- 1 and 2. Groundwater Sensitivity Regions 7

Table 1. Watershed names and six-digit HUC designations for basin management units 1, 2, and 5.

Six-digit HUC 6 Name BMU HUC 051002 Kentucky River 1 050902 areas along the Ohio River 2 051001 Licking River 2 051401 Salt River, Rolling Fork River, and Ohio River 2 050702 Big Sandy River 5 050901 Tygarts Creek, Little Sandy River, and Ohio River 5

Table 2. Watershed names and eight-digit HUC designations for basin management units 1, 2, and 5.

Eight-digit HUC 8 Name BMU HUC 05100201 North Fork Kentucky River 1 05100202 Middle Fork Kentucky River 1 05100203 South Fork Kentucky River 1 05100204 Kentucky River–Red River 1 05100205 Lower Kentucky River 1 05090201 Ohio River–Kinniconick Creek 2 05090203 Ohio River–Gunpowder Creek 2 05100101 Licking River 2 05100102 South Fork Licking River 2 05140101 Ohio River–Little Kentucky River–Harrods Creek 2 05140102 Salt River 2 05140103 Rolling Fork River 2 05140104 Ohio River–Sinking Creek 2 05070201 Big Sandy River 5 05070202 Upper Levisa Fork 5 05070203 Levisa Fork 5 05070204 Blaine Creek 5 05090103 Tygarts Creek–Ohio River 5 05090104 Little Sandy River 5

Groundwater Sensitivity Regions es, and the effects of resource extraction (principally The vulnerability of groundwater to nonpoint- oil and gas production and coal mining). source contamination varies geographically across Recognizing the need to develop a fl exible pro- Kentucky, and vertically at any given location, in re- gram for groundwater protection, DOW developed a sponse to both natural and man-made factors. method for rating and delineating regions of different Among the most important natural controls on groundwater sensitivity (Ray and O’dell, 1993) and the transport of pollutants to the groundwater system published a map showing the various groundwater are physiography (principally the topography, relief, sensitivity regions throughout the commonwealth land slope, and presence or absence of sinkholes or (Ray and others, 1994). Ray and O’dell (1993) con- caves); soil type and thickness; bedrock type; bedrock cluded that the natural factors controlling the potential structure (principally the bedrock porosity and per- for contamination of the shallowest aquifer can be as- meability and the presence or absence of faults, frac- sessed from three factors: the potential ease and speed tures, or solution conduits); and depth to groundwa- of vertical infi ltration, the maximum potential fl ow ve- ter. Overprinted on the natural environment are man- locity, and the potential for dilution by dispersion after made factors such as the type of land use, nature and a chemical enters the aquifer. amount of chemicals applied to agricultural and urban Groundwater sensitivity to nonpoint-source con- landscapes, wastewater and sewage-disposal practic- tamination generally decreases with depth as a result of the same factors: infi ltration is slower and more 8 Methods tortuous, allowing for degradation and dilution of the samples may have been included in the data sets used chemicals; fl ow velocities in deep groundwater sys- here if well depths were not recorded, however. tems are slower, allowing for additional degradation The following steps were taken to summarize and dilution of nonpoint-source chemicals; and disper- and evaluate the analytical data. sion and dilution are greater, because deep groundwa- 1. Query the repository database for reports of ter systems contain water from large recharge areas. analyses. Analytical reports were selected for Within the study area, the sensitivity of shallow groundwater-quality constituents that either groundwater to nonpoint-source contamination can determine the suitability of the water for vari- best be summarized by physiographic region (Ray and ous uses, provide geochemical signatures that others, 1994). The uppermost groundwater system characterize the regional groundwater fl ow is moderately sensitive in the Knobs and the Eastern system, have recognized or suspected impacts Kentucky Coal Field, but highly to extremely sensitive on human health, or record the impacts of in the Eastern Pennyroyal and Inner and Outer Blue- nonpoint-source contaminants on groundwa- grass Regions. ter. The parameters selected were: Local groundwater sensitivity may be very dif- Water properties: pH, total dissolved solids, ferent from these regional assessments, but local con- conductance, hardness, and total suspended ditions cannot be assessed in this regional summary solids of groundwater quality. Well depth is an approxi- Inorganic anions: chloride, fl uoride, sulfate mate indicator of whether a shallow, intermediate, Metals: arsenic, barium, iron, man ganese, or deep groundwater system is being sampled. Two mercury factors limit the usefulness of well depth as an indi- Nutrients: ammonia, nitrate, nitrite, ortho- cator of groundwater systems, however. First, many phosphate, total phosphorus wells have no depth recorded, are uncased throughout Pesticides: alachlor, atrazine, cyanazine, much of their length and thus collect water from vari- metolachlor, simazine ous depths, or are drilled deeper than needed to serve Volatile organic compounds: benzene, ethyl- as a water-storage system. Second, a shallow well may benzene, toluene, xylenes, MTBE actually tap a deep groundwater fl ow system if the Both dissolved concentrations (measured well is located near the discharge region of the ground- from a sample that had been fi ltered to remove water fl ow system. suspended particulate material) and total concentrations (measured from an unfi ltered sam- Methods ple) were retrieved from the database for metals. Recorded groundwater analyses were extracted Many of the analytes of interest have been from the Kentucky Groundwater Data Repository. reported under a variety of names, and not all The intent was to extract and summarize analyses of analytical results are identifi ed by unique CAS samples that are representative of regional groundwa- numbers (Chemical Abstract Service registry ter quality, and to avoid reports from wells or springs numbers), so queries were written to return all that were known or suspected of being contaminated variations of the analyte name. For example, by local conditions. For this reason, samples collected phosphorus measurements are reported as for the Resource Conservation and Recovery Act, Solid “orthophosphate,” “orthophosphate-P (PO4- Waste, or Underground Storage Tank regulatory pro- P),” “phosphate,” “phosphate-total,” “phos- grams were excluded. Even so, some of the anomalous phate-ortho,” “phosphorus,” “phosphorus-or- values that were included in the resulting data sets tho,” “phosphorus-total,” “phosphorus-total may represent local or point-source contamination be- by ICP,” and “phosphorus-total dissolved.” cause there was no basis in the data reports for exclud- The results were inspected to ensure that each ing those results. Determining whether these results resulting data set contained the appropri- are naturally occurring extreme values, inaccurate data ate chemical species. All reported analytical entries, or are the result of pollutants would require units were converted to milligrams per liter. reviewing the original sample collection reports or vis- Each sample site was assigned a basin iting the site. Those activities are beyond the scope of management unit number, six-digit HUC num- this project. ber, major watershed name, and physiograph- Analytical results from wells deeper than 1,000 ic region designation so that the data could be ft were excluded because such deep wells are not gen- grouped into these categories. GIS coverages erally used for domestic water supplies. Some deep of six-digit HUC’s and physiographic regions Methods 9

were obtained from the KGS Web site (www. as an accurately measured concentration. The uky.edu/KGS/gis/). preferred treatment of censored data depends 2. Delete records that do not provide useful on the purpose of the analysis. For example, information. The Environmental Protection the EPA has established guidelines for treating Agency has established maximum contami- censored data in Resource Conservation and nant levels for chemicals that present health Recovery Act investigations (U.S. Environ- risks. Some analytical results in the groundwa- mental Protection Agency, 1992). The goals of ter data repository were reported only as “less this report are to summarize ambient ground- than” a detection limit, where the detection water quality and to locate regions affected or limit was greater than the MCL. These records threatened by nonpoint-source contamination. do not provide useful analytical data for this Therefore, censored data were treated as if the report and so were eliminated from the data analyte concentration was equal to the detec- sets. tion limit, but the censored data were ranked 3. Count the number of analytical results and below actual measurements at that value when the number of sites sampled for each constit- quartile values were determined. For example, uent. Many wells and springs were sampled a value reported as less than a detection limit more than once, so there may be more than of 0.0004 mg/L was ranked below a measured one reported concentration for an analyte at a value of 0.0004 mg/L and above a measured particular site. The number of individual sites value of 0.0003 mg/L for the quartile determi- was determined by counting unique location nations. identifi cation numbers associated with the 5. Determine the number of sites at which analytical records. measurements exceeded water-quality stan- 4. Determine quartile values. Water-quality dards. Because many samples may have been data are generally positively skewed; that is, analyzed from a particular well or spring over concentrations are not symmetrically distrib- time, the number of sites at which parameters uted about a mean value and there are some exceed critical values is a better indicator of extremely high values. The combined effect of regional groundwater quality than the num- a non-normal distribution and extreme out- ber of measurements that exceed those values. lier values is that parametric statistical mea- Water-quality standards were provided by sures such as mean and standard deviation DOW (Table 3). do not effi ciently describe the data. Nonpara- 6. Map sample sites and use various symbols to metric statistical measures such as quartile represent concentration ranges and to show values and interquartile range provide a where MCL or other critical values were better description of the data population exceeded. Maps show sample site locations, site (see Helsel and Hirsch, 1992, for example). distributions, concentration ranges, and areas where concentrations exceed MCL’s or other The quartile values are: critical values. Maps also reveal whether analyte zero quartile value: the minimum value; values are randomly distributed or are related all other values are greater to watersheds, physiography, or land use. fi rst quartile value: the value that is greater than 25 percent of all values Maps were generated using ArcView GIS 3.1. second quartile value: the median value; At the scale used in this report and depending greater than 50 percent of all values on symbol size and shape, sites within a third quartile value: the value that is great- few hundred feet of each other may not be er than 75 percent of all values resolved as separate locations. Therefore, the fourth quartile value: the maximum value maps are useful for illustrating the general Maximum and minimum concentrations may location of sites where various criteria are be anomalous, but the median value and the met or exceeded, but they may not provide interquartile range (range of values between an accurate count of those sites. All maps are the fi rst and third quartile values, also equal to projected on the NAD 83 datum. the central 50 percent of the data) provide an 7. Use summary tables, probability plots, and effi cient summary of the data. Many analytical box-and-whisker diagrams to summarize and results are censored data; that is, they are re- illustrate the data and to compare analytical ported as less than a detection limit rather than results between watersheds, physiographic 10 Methods

Table 3. Parameters and water-quality standards used for data summaries. Parameter Standard Source (mg/L unless otherwise noted) Conductance 10,000 µS No MCL or SMCL; approximately corresponds to brackish water Soft: 0–17 Slightly hard: 18–60 Hardness (calcium and Moderately hard: 61–120 U.S. Geological Survey Water magnesium) Hard: 121–180 Properties Very hard: > 180

pH 6.5–8.5 pH units SMCL Total dissolved solids 500 SMCL Total suspended solids 35 KPDES

Chloride 250 SMCL Inorganic Sulfate 250 SMCL Ions Fluoride 4.0 MCL Arsenic 0.010 MCL Barium 2.0 MCL

Metals Iron 0.3 SMCL Manganese 0.05 SMCL Mercury 0.002 MCL Ammonia-nitrogen 0.110 DEP Nitrate-nitrogen 10.0 MCL

Nutrients Nitrite-nitrogen 1.0 MCL Orthophosphate-phosphorus 0.04 Texas surface-water standard Total phosphorus 0.1 NAWQA 2,4-D 0.007 MCL Alachlor 0.002 MCL Atrazine 0.003 MCL Pesticides Cyanazine 0.001 HAL Metolachlor 0.1 HAL Simazine 0.004 MCL Benzene 0.005 MCL Ethylbenzene 0.7 MCL Volatile Organic Toluene 1.0 MCL Compounds Xylenes 10 MCL MTBE 0.050 DEP

MCL: Maximum contaminant level allowed by EPA in drinking water. Higher concentrations may present health risks. SMCL: Secondary maximum contaminant level (EPA). Higher concentrations may degrade the sight, smell, or taste of the water. NAWQA: National Water-Quality Assessment Program, U.S. Geological Survey. Higher concentrations may promote eutrophication. HAL: Health advisory level. Higher concentrations may present concerns for human health. KPDES: Kentucky Pollution Discharge Elimination System. Standard set for water-treatment facilities. DEP: Kentucky Department for Environmental Protection risk-based concentration. Higher concentrations may present health risks. Methods 11

regions, or other groupings. Summary 3.0 times the interquartile range above the tables list the number of measurements and third quartile value or below the fi rst quartile sites, quartile values, and the number of value are shown as squares with plus signs sites where concentrations exceed MCL’s through them. The presence of far outside or other standard values for each BMU. points indicates suspect values or a highly skewed distribution. Probability plots and Normal probability plots (cumulative data box-and-whisker plots were generated using plots) (Fig. 2) show the distribution of values as Statgraphics Plus for Windows v. 4.1. a percentage of the total number of analytical The general approach for each analyte is: results. They provide an easy way to identify 1. Defi ne the analyte; summarize common natu- outlier values. The cumulative data plots in ral sources, uses, and potential contaminant this report exclude the highest and lowest 0.1 sources; list relevant water-quality criteria; percent of the values so that extremely high and describe how excessive amounts affect or low values do not compress the display of water use and human health. the majority of the data. Therefore, probability 2. Summarize analytical reports from BMU’s 1, plots of data sets that contain more than 1,000 2, and 5 by constructing summary data tables measurements do not show the absolute and cumulative data plots. maximum and minimum values. Each plot also 3. Show sample-site distribution and sites where includes a straight line that shows the locus of water-quality standards are met or exceeded points along which the data would fall if the by mapping sample sites and concentration measurements were normally distributed. ranges. 4. Summarize data for each physiographic re- Box-and-whisker diagrams (Fig. 3) show the gion and major watershed by constructing median value and the interquartile range, and box-and-whisker plots. illustrate how clustered or scattered analytical 5. Compare data by site type (well versus spring) results are. The box extends from the fi rst and sample type (total versus dissolved) by quartile value to the third quartile value, constructing box-and-whisker plots. thereby including the central 50 percent of the 6. Evaluate the impact on shallow (less than data. Either a center line or notches within the 200 ft), intermediate (200 to 500 ft), and deep box shows the median value. Whiskers extend (greater than 500 ft) groundwater fl ow systems from each edge of the box a distance of 1.5 by plotting concentrations versus well depth. times the interquartile range. Values that are 7. Summarize probable causes of observed con- more than 1.5 times the interquartile range are centrations and distribution of values. shown as squares; values that are more than

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Figure 2. Cumulative data plot for all pH values reported in Figure 3. Box-and-whisker plot for all pH values reported in Kentucky groundwater. Kentucky groundwater.