USGS

WATER-QUALITY ASSESSMENT OF THE OZARK PLATEAUS STUDY UNIT, ARKANSAS, KANSAS, MISSOURI, AND OKLAHOMA-SUMMARY OF INFORMATION ON PESTICIDES, 1970-90

By Richard W. Bell, Robert L. Joseph, and David A. Freiwald

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Abstract

Historical pesticide data from 1970-90 were compiled for 140 surface-water, 92 ground-water, 55 streambed- sediment, and 120 biological- tissue sampling sites within the Ozark Plateaus National Water Quality Assessment Program study unit. Surface-water, bed-sediment, and biological- tissue sites have drainage basins predominantly in the Springfield and Salem Plateaus; ground-water sites are predominantly located in the Osage Plains and Mississippi Alluvial Plain. Many sites were sampled only once or twice during this period. A large percentage of the samples was collected in the mid-1970's and early 1980's for surface-water, 1990 for ground water, the late 1980's for bed sediment, and the early 1980's for biological tissue.

Pesticide use was approximately 4.2 million pounds per year of active ingredients from 1982-85 in the study unit and was generally greatest in the Salem and Springfield Plateaus pasturelands and in the Osage Plains and Mississippi Alluvial Plain cropland areas. The most frequently applied pesticide in the study unit was 2,4-D. Alachlor was the second most applied pesticide. Corn, pasture, rice, sorghum, and soybeans received approximately 90 percent of the pesticides applied within the study unit. The highest pesticide application rate per acre occurred on these crops in the Mississippi Alluvial and Osage Plains. Pastureland was the predominant crop type in 50 of the 94 counties in the study unit.

Toxaphene, the pesticide having the most number of detections in surface water, was found in 17 of 866 samples from 5 of 112 sites. Concentrations ranged from 0.1 to 6.0 micrograms per liter. Six other pesticides or pesticide metabolites were detected in 12 or more surface-water samples: DDE, dieldrin, DDT, aldrin, 2,4-D, and lindane. The maximum concentration for these pesticides was less than 1.0 micrograms per liter.Atrazine, the pesticide having the most number of detections in ground water, was found in 15 of 95 samples from 15 of 79 wells with concentrations ranging from 0.1 to 8.2 micrograms per liter. Metolachlor, alachlor, and prometon were detected more than once with maximum concentrations less than 1.0 micrograms per liter, except for prometon (2.4 micrograms per liter).

Chlordane was the pesticide having the most number of detections in bed sediment and biological tissue. Chlordane was detected in 12 of 73 samples from 10 of 45 bed-sediment sites with concentrations ranging from 2.0 to 240 micrograms per kilogram. In biological tissue, chlordane was found in 93 of 151 samples from 39 of 53 sites with concentrations ranging from 0.009 to 8.6 milligrams per kilogram. Other pesticides or pesticide metabolites detected more than once in bed sediment include DDT, DDD, p,p'-DDE, DDE, and hexachlorobenzene and in biological tissue include DDT, p,p'-DDE, and hexachlorobenzene.

Quality criteria or standards have been established for 15 of the pesticides detected in the study unit. For surface-water samples, the drinking water maximum contaminant level for alachlor was exceeded in one sample from one site in 1982. For ground-water samples, the drinking water maximum contaminant level for atrazine was exceeded in four samples from four wells in 1990. For biological-tissue samples collected during the years 1982-89, the fish tissue action levels for chlordane (26 samples, 19 sites), heptachlor epoxide (3 sites; 3 samples), p,p'-DDE (2 sites; 2 samples), dieldrin (2 sites; 2 samples), and mirex (1 site; 1 sample) were exceeded. For bed-sediment samples, quality criteria or standards were not exceeded for any pesticide. Pesticides do not pose any widespread or persistent problems in the study unit, based on the limited number of samples that exceeded quality criteria and standards.


TABLE OF CONTENTS

ILLUSTRATIONS
  1. Location of Ozark Plateaus study unit, major river basins, physiographic areas, and surface extent of hydrogeologic units
  2. Major pesticides use in the study unit by county, 1982-85.
  3. Pesticide application rate for counties within in the study unit
  4. Crop types receiving the largest pesticide applications for counties within the study unit.
  5. Location of surface-water pesticide sampling sites and sites where pesticides were detected
  6. Location of ground-water pesticide sampling sites and sites where pesticides were detected
  7. Location of bed-sediment pesticide sampling sites and sites where pesticides were detected
  8. Location of biological-tissue pesticide sampling sites and sites where pesticides were detected
TABLES
  1. Land-use percentage by physiographic area
  2. Estimated pesticide applications in the study unit, 1982-85, and description of pesticide type and use
  3. Major pesticide data sources available for the study unit
  4. Summary of number of pesticide sampling sites and samples collected for each sample type, by agency
  5. Site and basin characteristics of surface-water sampling sites
  6. Site characteristics of ground-water sampling sites
  7. Site and basin characteristics of bed-sediment sampling sites
  8. Site and basin characteristics of biological-tissue sampling sites
  9. Statistical summary of pesticide data from surface-water sampling sites for water years 1970-9019
  10. Statistical summary of pesticide data from ground-water sampling sites for water years 1970-90
  11. Statistical summary of pesticide data from bed-sediment sampling sites for water years 1970-90
  12. Statistical summary of pesticide data from biological-tissue sampling sites for water years 1970-90
  13. Comparison of selected quality criteria and standards with maximum detected concentrations in surface-water, ground-water, bed-sediment, and biological-tissue samples

U.S. Department of the Interior, U.S. Geological Survey
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Last modified: Thursday, September 01 2005, 02:25:04 PM
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