FACTORS AFFECTING LEACHING IN AGRICULTURAL AREAS AND AN ASSESSMENT OF AGRICULTURAL CHEMICALS IN THE GROUND WATER OF KANSAS By Charles A. Perry, F. Victor Robbins, and Philip L. Barnes U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 88-4104 Prepared in cooperation with the KANSAS DEPARTMENT OF HEALTH AND ENVIRONMENT Lawrence, Kansas 1988 DEPARTMENT OF THE INTERIOR DONALD PAUL HODEL, Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director For additional information write to: Copies of this report can be purchased from: U.S. Geological Survey District Chief Books and Open-File Reports U.S. Geological Survey Denver Federal Center, Bldg. 810 1950 Constant Avenue - Campus West Box 25425 Lawrence, Kansas 66046 Denver, Colorado 80225 CONTENTS Page Abstract ............................................................................. 1 Introduction .......................................................................... 1 Purpose and scope ............................................................... 2 Acknowledgments .............................................................. 2 Hydrologic factors affecting leaching ................................................... 2 Surficial geology ................................................................ 2 Principal aquifers ............................................................... 4 Climate ........................................................................ 5 Soil ............................................................................ 7 Agricultural and chemical factors affecting ground-water quality ........................ 11 Agricultural land use .......................................................... 11 Agricultural chemical use ...................................................... 13 Fertilizers ............................................................... 13 Nitrogen .......................................................... 13 Phosphorus and potassium .......................................... 16 Lime ............................................................. 17 Pesticides ............................................................... 17 Chemical properties of pesticides .................................... 23 Pesticide-soil interactions .......................................... 25 Drinking-water standards ............................................................ 28 Inorganic constituents ......................................................... 28 Trace elements ................................................................ 31 Pesticides ..................................................................... 31 Preliminary ground-water-quality assessment .......................................... 31 Kansas ground-water-quality monitoring network, 1976-81 ........................ 31 Kansas farmstead-well survey, 1985-86 .......................................... 33 Additional sampling, 1985-86 ................................................... 38 Need for future study ................................................................. 40 Problem ...................................................................... 40 Major objectives ............................................................... 40 Approach ..................................................................... 40 Conclusions ......................................................................... 42 References .......................................................................... 43 Supplemental information ............................................................ 46 Figure Page 1. Map and cross section showing generalized geology and physiographic provinces .... 3 2. Map showing principal aquifers ................................................ 5 3. Map showing average annual precipitation, 1951-80, and precipitation reporting districts of the National Oceanic and Atmospheric Administration ................ 6 4. Graph showing average monthly precipitation in Kansas as a percentage of total average annual precipitation, 1951-80 .......................................... 7 5. Diagram showing classification of soil textures .................................. 9 6. Diagram showing typical soil-moisture-release curves for three common soil types . 10 7. Map showing distribution of teachability classes of Kansas soil ................... 12 8. Map showing ground-water regions and percentage of ground-water samples with dissolved nitrate-nitrogen concentrations exceeding drinking-water standard of 10 milligrams per liter .................................................... 37 CONTENTS-Continued Figure Page 9. Map showing location of Kansas State University agronomy farms and experimental stations ........................................................ 41 Table Page 1. Average annual precipitation, 1951-80, for nine reporting districts ................ 6 2. Number of irrigated acres in 1984 for nine reporting districts ..................... 8 3. Soil-texture classification ..................................................... 8 4. Typical soil-moisture levels for three soil textures ............................... 9 5. Annual crop-moisture use for typical Kansas crops .............................. 11 6. Number of acres in each leachability class in Kansas ............................ 12 7. Common fertilizers and their chemical formulas ................................ 14 8. Nitrogen application rates for alternative timing of application .................. 15 9. Nitrogen application rates recommended by Kansas Cooperative Extension Servicefor different locations and crops ........................................ 16 10. Pesticide usage on crops and pasture or rangeland in Kansas, 1978 ............... 18 11. Total and irrigated crop acreages during 1978 and 1984 ......................... 24 12. Chemical properties and toxicity of selected pesticides .......................... 26 13. Summary of drinking-water standards and recommended limits for inorganic constituents ................................................................ 29 14. Summary of drinking-water standards and chronic health effects for trace elements 32 15. Health advisory levels for pesticides in drinking water .......................... 34 16. Dissolved nitrate-nitrogen concentrations in Kansas ground-water supplies, 1976-81 37 17. Pesticides detected in Kansas ground water, 1985-86 ............................ 38 18. Major herbicide usage during 1978, by reporting district ........................ 47 CONVERSION FACTORS Information in the following table may be used to convert the inch-pound units of measurement used in this report to metric (International System) units: Multiply inch-pound unit By To obtain metric unit inch 25.4 millimeter foot 0.3048 meter mile 1.609 kilometer acre 4,047 square meter quart 0.9464 liter pound 453.6 gram ounce 28,349 milligram ton (short) 0.9072 megagram pound per acre (Ib/acre) 0.112 gram per square meter inch per foot 83.333 millimeter per meter gallon per minute 0.06308 liter per second pound per square inch 6.895 kilopascal degree Fahrenheit (°F) °C = 5/9 (°F -32) degree Celsius (°C) Sea level: In this report, sea level refers to the National Geodetic Vertical Datum of 1929 a geodetic datum derived from a general adjustment of the first-order level nets of both the United States and Canada, formerly called "Mean Sea Level." FACTORS AFFECTING LEACHING IN AGRICULTURAL AREAS AND AN ASSESSMENT OF AGRICULTURAL CHEMICALS IN THE GROUND WATER OF KANSAS By Charles A. Perry l, Victor Robbins2, and Philip L. Barnes3 ABSTRACT was detected in water at 9 of 11 wells. Cyanazine was detected in water at three wells; Hydrologic factors and agricultural practices metolachlor at two wells; and metribuzin, that affect the leaching of agricultural alachlor, simazine, and propazine were chemicals were assessed to evaluate the extent detected at one well each. and severity of chemical contamination of ground water in Kansas. Climate, surficial Because the largest concentrations of geology, soil type, and principal aquifers deter­ atrazine (46 micrograms per liter), cyanazine mine the types of crops suitable to be planted, (3.7 micrograms per liter), metolachlor (55 types of tillage, conservation and irrigation micrograms per liter), and the only detectable practices, and affect the quantity and method concentrations of metribuzin (14 micrograms of application of agricultural chemicals. per liter) and alachlor (1.9 micrograms per liter) were from water at only one site, it is uncertain In general, the more sand in the soil the how widespread the problem of large more susceptible it will be to leaching of concentrations of these herbicides is agricultural chemicals. Soils in Kansas are throughout the State. The herbicides 2,4-D, grouped into four classes of leachability--from 2,4,5-T, picloram, and alachlor and the class 1, with the largest permeability, to class 4, insecticides chlordane and heptachlor epoxide with the smallest. have been detected by other researchers in ground water from domestic-supply wells in the As a result of years of nitrogen application State. to the soil, the 10-milligram-per-liter drinking- water standard for nitrate-nitrogen was A plan for a proposed study of the leaching exceeded occasionally in 13 of 14 and fate of pesticides in the saturated and geohydrologic regions in the State. unsaturated zones in Kansas includes a comprehensive investigation of pesticides in soil During 1978, about 23.8 million pounds of and ground water, data collection,