Carey, Daniel I.

Conrad, Philip G.

Dinger, James S.

McCourt, Matthew J.

Webb, James S.

English

University of Kentucky

University of KentuckyUKnowledgeKentucky Geological Survey Information Circular Kentucky Geological Survey1999Ground-Water Quality in Kentucky: Nitrate-NitrogenPhilip G. ConradUniversity of KentuckyDaniel I. CareyUniversity of Kentucky, carey@uky.eduJames S. WebbKentucky Division of WaterJames S. DingerUniversity of Kentucky, james.dinger@uky.eduMatthew J. McCourtUniversity of KentuckyRight click to open a feedback form in a new tab to let us know how this document benefits you.Follow this and additional works at: https://uknowledge.uky.edu/kgs_icPart of the Geology CommonsThis Report is brought to you for free and open access by the Kentucky Geological Survey at UKnowledge. It has been accepted for inclusion inKentucky Geological Survey Information Circular by an authorized administrator of UKnowledge. For more information, please contactUKnowledge@lsv.uky.edu.Repository CitationConrad, Philip G.; Carey, Daniel I.; Webb, James S.; Dinger, James S.; and McCourt, Matthew J., "Ground-Water Quality in Kentucky:Nitrate-Nitrogen" (1999). Kentucky Geological Survey Information Circular. 61.https://uknowledge.uky.edu/kgs_ic/61WHAT IS NITRATE AND WHY IS ITIMPORTANT?Nitrate (NO3–) is composed of the elements oxygen andnitrogen, and is an important source of nitrogen for plantand animal life; but too much nitrate in drinking water canbe harmful to human health. Common sources of nitrate inwater include plant and animal matter, human and animalwaste, household septic systems, and fertilizers. Because itdissolves readily in water, nitrate from these sources is usuallypresent at least in low concentrations in drinking-watersupplies, regardless of the water source.Utility companies that provide public water supplies testthe water for concentrations of nitrate. This testing is muchless common for private water supplies, however. More than900,000 people in Kentucky use ground-water supplies,including approximately 500,000 supplied through publicutilities and at least 400,000 using private wells or springs.Excess nitrate in drinking water has been found to causemethemoglobinemia, or Blue Baby Syndrome, in infants lessthan 6 months old (Kross and others, 1992; Bruning-Fannand Kaneene, 1993). The U.S. Environmental ProtectionAgency has established maximum contaminant levels (MCL’s)for nitrate in public drinking water because of health concerns.The MCL for nitrogen can be expressed as units of nitrate(NO3–) or as units of nitrogen (N), referred to as nitrate-nitrogen (nitrate-N or NO3–-N). The MCL expressed as unitsof nitrate is 45 milligrams per liter (mg/L). The MCLexpressed as units of nitrate-nitrogen is 10 mg/L (U.S.Environmental Protection Agency, 1994). Some laboratoriesuse the term “parts per million” (ppm), which is essentiallyequivalent to mg/L in fresh water. Because most laboratoriesreport nitrate as units of nitrate-nitrogen, that form ofmeasurement is used in this report.WATER-QUALITY VARIATIONSThe map shows the concentration of nitrate-nitrogen inprivate wells, public wells, and springs across Kentucky.Samples were collected from the 1940’s to the mid-1990’s.Less than 1 percent of the wells are industrial monitoringwells. Red squares indicate concentrations greater than 10mg/L (exceeding the MCL), green dots indicate concentrationsabove 5 and up to 10 mg/L, and black dots indicateconcentrations less than or equal to 5 mg/L.The map and table show some of the broad patterns ofhigh, moderate, and low concentrations of nitrate in Kentuckyground water. The concentration measured at individualmonitoring points may not represent present-day conditions,however. Caution should be used in interpreting thesignificance of individual monitoring points shown on themap.The distribution of samples analyzed for nitrate is notuniform. For example, several counties in the Blue GrassRegion and the Eastern Kentucky Coal Field have analysesfor fewer than 15 wells or springs, whereas a few countiesin other parts of the State have more than 60. Samplinginformation from the Kentucky Ground-Water DataRepository used in this report does not have a uniformdistribution because it was compiled from several differentsampling programs. Some of these sampling programstargeted specific areas in Kentucky. Most sampled springsare in karst areas, where natural conduits in rock are largeand sinkholes are present in nearby terrain. Most of thekarst of Kentucky is in the Blue Grass and PennyroyalRegions.Data used in this report are from sites that were sampledat various times of the year. The time of year that samplesare collected can affect the nitrate concentration detected.Some wells and springs have a greater concentration ofnitrate from mid-December to mid-February. Some sitesmay also have a higher concentration within days or weeksof nearby use of fertilizers or application of manure.The map shows the physiographic regions of Kentucky.The topography, geology, dominant soil types, and ground-water flow systems are quite different in the differentregions. The physical and biological environment of a regionaffects the occurrence and movement of nitrate in groundwater, and how quickly nitrate is reduced in the subsurface.Other factors can also have a local influence oncontamination of ground water. If a well is located near aninefficient septic system, nitrate may enter shallow groundwater at high concentrations. Frequent use of nitratefertilizers or concentrated application of manure may alsolocally contaminate the ground water. Ineffective sealsaround well casings may allow unrestricted downwardmovement of contaminated shallow ground water.Nitrate-nitrogen concentrations are grouped by welldepth in the table. Concentrations from sampled springsare also listed. Data for a well were included in the tableGround-Water Quality in Kentucky:Nitrate-NitrogenPhilip G. Conrad1, Daniel I. Carey1, James S. Webb2,James S. Dinger1, and Matthew J. McCourt31Kentucky Geological Survey2Kentucky Division of Water3University of Kentucky Department of GeographyISSN 0075-5583INFORMATION CIRCULAR 60SERIES XI, 1999KENTUCKY GEOLOGICAL SURVEYDonald C. Haney, State Geologist and DirectorUNIVERSITY OF KENTUCKY, Lexingtontext continued on next pagehttps://doi.org/10.13023/kgs.ic60.11only if the well’s total depth was on record, or if the wellwas hand-dug. Some sites were sampled more than once;when more than one analysis was available, the analyseswere averaged to produce one average value for the site.For example, for wells from 0 to 50 ft deep, there were 842sites and 1,051 analyses; some of those 842 sites had beensampled more than once.Percentiles in the table show the portion of wells that areequivalent to or below a given concentration. For example,for wells from 0 to 50 ft deep, 50 percent of the wells had anitrate-nitrogen concentration of 1.2 mg/L or less, and 90percent of the wells had a concentration of 8.3 mg/L or less.Hand-dug wells are grouped in the second column of thetable, but some of the wells in the 0–50 ft category are alsohand-dug. Hand-dug wells are generally less than 50 ft deepand therefore are represented in both the hand-dug categoryand the 0–50 ft category.Data in the table show that the MCL was exceeded inapproximately 10 percent of hand-dug wells (38 out of 391),7 percent of wells from 0 to 50 ft deep (59 out of 842), 5percent of wells from 51 to 100 ft deep (77 out of 1,506), 3percent of wells from 101 to 150 ft deep (25 out of 737), and1 percent of wells from 151 to 500 ft deep (7 out of 660). Forall wells (0–500 ft category), approximately 4.5 percentexceeded the MCL. Approximately 3 percent of sampledsprings (31 out of 1,018) exceeded the MCL.These data show that the likelihood of well contaminationis highly dependent on well depth. Concentrations over theMCL are most common in hand-dug wells, and least commonin wells more than 150 ft deep. Hand-dug wells are especiallyprone to contamination because they are recharged by veryshallow ground water, and shallow ground water generallyhas higher concentrations of nitrate than deep ground water.WATER-QUALITY CONCERNSCitizens with concerns about the quality of water in privatewells or springs should contact their local health departmentor the Groundwater Branch of the Kentucky Division ofWater, which is a division of the Kentucky Natural Resourcesand Environmental Protection Cabinet (Frankfort). TheGroundwater Branch can provide literature on maintenanceof private wells and information on sampling for wateranalysis.HOW DID THIS PUBLICATION COMEABOUT?This publication is a product of the Kentucky InteragencyGround-Water Monitoring Network (GNet) program. TheKentucky Geological Survey was mandated by the Kentuckylegislature in 1998 to implement the long-term monitoringnetwork in coordination with other agencies (KRS 151.625)and to report on the characteristics of ground-water resources.A portion of the sampling required for long-term ground-water characterization has been implemented, and variousagencies are taking an active role. The first reports by theGNet program use both new and old data in order to viewbroad trends in ground-water quality.GNet program activities offer increased consistency indata collection methods, both geographically and over time.Data collected by GNet are available to the public throughthe Kentucky Ground-Water Data Repository at the KentuckyGeological Survey. The program also uses these data inreports that characterize the quality, quantity, and availabilityof Kentucky’s ground-water resources.The Interagency Technical Advisory Committee onGroundwater (ITAC) was also created by statute (KRS151.629). ITAC provides advice and assistance to GNet. ITACis chaired by the director of the Kentucky Water ResourcesResearch Institute and has representatives from 14 agencies:• Kentucky Department for Environmental Protection• Kentucky Department for Natural Resources• Kentucky Department for Surface Mining Reclamationand Enforcement• Kentucky Department of Mines and Minerals• Kentucky Division of Conservation• Kentucky Division of Environmental Health andCommunity Safety• Kentucky Division of Forestry• Kentucky Division of Pesticides• Kentucky Division of Waste Management• Kentucky Division of Water• Kentucky Geological Survey• Kentucky Water Resources Research Institute• U.S. Geological Survey• University of Kentucky College of AgricultureTHE KENTUCKY GROUND-WATER DATAREPOSITORYThe Kentucky Ground-Water Data Repository wasestablished to archive and distribute ground-water data andwas an important source of data for this report. Sources ofdata for the repository include the Kentucky Division ofWater, Kentucky Geological Survey, U.S. Geological Survey,National Uranium Resource Evaluation Program, and theU.S. Environmental Protection Agency. Types ofcomputerized data in the repository include general water-well information, water-quality data, trace-organic analysis,spring data, discharge measurements, and ground-waterdye-trace data. Because the various sampling organizationshave different sampling methods, the accuracy of these datacannot be guaranteed. The repository is located at theKentucky Geological Survey in the Mining and MineralResources Building on the University of Kentucky campusin Lexington.REFERENCES CITEDBruning-Fann, C.S., and Kaneene, J.B., 1993, The effect ofnitrate, nitrite, and N-nitroso compounds on humanhealth—A review: Veterinary and Human Toxicology,v. 35, no. 6, p. 521–538.Kross, B.C., Ayebo, A.D., and Fuortes, L.J., 1992,Methemoglobinemia—Nitrate toxicity in rural America:American Family Physician, v. 46, no. 1, p. 183–188.U.S. Environmental Protection Agency, 1994, Nationalprimary drinking water standards: U.S. EnvironmentalProtection Agency, EPA 810-F-94-001, 2 p.© 1999University of KentuckyFor further information contact:Manager, Office of Communications and Technology TransferKentucky Geological Survey228 Mining and Mineral Resources BuildingUniversity of KentuckyLexington, KY 40506-0107SCALE  1:1,750,000100 Miles500500 50 100 Kilometers50TradewaterOhioOhioMississippiCumberland GreenCumberlandBig SandyLittle SandyTygarts CreekOhioLickingKentuckyOhioOhioOhioOhioGreenTennesseeOhioSaltEXPLANATIONNitrate-nitrogen concentrationsGreater than 10 mg/L5.1 to 10 mg/Lless than or equal to 5 mg/LNITRATE-NITROGEN CONCENTRATIONS IN  WELLS  AND  SPRINGS IN KENTUCKYData from Kentucky Ground-WaterData Repository, July 1998Information Circular  60Series XI, 1999Kentucky Geological SurveyDonald C. Haney, State Geologist and DirectorUNIVERSITY of KENTUCKY, LexingtonNitrate-Nitrogen (mg/L)Dissolved and total nitrate-nitrogen in sampled wells and springs of Kentucky.Data used are a composite of sampling from the 1940's to the present.Depth of wells (ft) Dug wells 0–50 51–100 101–150 151–500 0–500 SpringsMaximum 150 150 67 97 76 150 3490th percentile 9.6 8.3 7.2 6.1 2.7 6.7 4.075th percentile 4.9 3.7 3.3 2.6 1.1 2.8 2.250th percentile (median) 1.9 1.2 0.7 0.6 0.2 0.6 1.025th percentile 0.6 0.2 0.1 0.1 0.1 0.1 0.510th percentile 0.2 0.1 nd nd nd nd 0.1Average 4.3 3.1 2.5 2.3 1.3 2.4 1.7Standard deviation 10.0 6.7 4.6 5.7 4.6 5.4 2.3Sites with nitrate-nitrogen data 391 842 1,506 737 660 3,745 1,018Sites averaging above MCL (10 mg/L) 38 59 77 25 7 168 31Percent above MCL 9.7% 7.0% 5.1% 3.4% 1.1% 4.5% 3.0%Sites averaging above ½ MCL 95 157 247 99 29 532 136Percent above ½ MCL 24.3% 18.6% 16.4% 13.4% 4.4% 14.2% 13.4%Number of analyses for sites 391 1,051 1,668 931 839 4,489 2,604Number of analyses above MCL 38 59 89 26 9 183 36Number of analyses above ½ MCL 95 180 259 108 30 577 172Total sites known in Kentucky > 200,000 unknownPhysiographic areasEastern and Western Kentucky Coal FieldsInner Blue GrassOuter Blue GrassThe KnobsEastern PennyroyalWestern PennyroyalAlluvium or glacial depositsJackson PurchaseRiver basin boundaryRiver basin nameGreenLakeBarkleyKentuckyLakeDale HollowLakeMinimum nd nd nd nd nd nd ndnd=not detectedNLakeCumberlandCartography by Terry Hounshellhttps://doi.org/10.13023/kgs.ic60.11DISCLAIMERThe Kentucky Geological Survey provides online versions of its publications as a publicservice. Publications are provided as Adobe PDF (portable document format) files. Hard-copy versions are available for purchase by contacting the Survey at:Kentucky Geological SurveyPublication Sales Office228 Mining and Mineral Resources BuildingUniversity of KentuckyLexington, Kentucky 40506-0107Phone: 606-257-5500Fax: 606-257-1147Selected KGS reports published before 1999 have been scanned and converted to PDFformat. Scanned documents may not retain the formatting of the original publication. Inaddition, color may have been added to some documents to clarify illustrations; in thesecases, the color does not appear in the original printed copy of the publication. Everyeffort has been made to ensure the integrity of the text. KGS maps and charts are suppliedeither whole or in part and some are too large to be printed on most plotters. Open-filereports are reproduced from the best available copy provided by the author, and have notundergone KGS technical or editorial review.The Kentucky Geological Survey disclaims all warranties, representations, orendorsements, expressed or implied, with regard to the information accessed from, or via,this server or the Internet.

Ground-Water Quality in Kentucky: Nitrate-Nitrogen

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Ground-Water Quality in Kentucky: Nitrate-Nitrogen

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