ENVIRONMENTAL EDUCATION SERIES
ENVIRONMENTAL QUALITY
Agriculture & Natural Resources

EXTENSION ENVIRONMENTAL EDUCATION, AUBURN UNIVERSITY, AL 36849-5647
Results Of A National Pesticide Survey
ANR-719, 1992, Jesse C. LaPrade, Extension Environmental Specialist, Community Resource Development,and James E. Hairston, Extension Agronomist—Water Quality, Agronomy and Soils, Alabama Cooperative Extension System, Auburn University
Scope Of The Survey
      In January, 1991, the U. S. Environmental Protection Agency (EPA) completed its 5 year national survey of pesticides and nitrates in drinking water wells and reported the results. The survey results statistically represent approximately 94,600 drinking water wells at 38,300 community water systems (CWS) and over 10.5 million rural domestic wells throughout the United States.

Survey Objective
      The survey was designed to determine the frequency and concentration of the presence of pesticides and nitrate in drinking water wells nationwide. EPA has not and will not publish within the national survey any data taken at local, county, or state levels.

Results Of The Survey
      Nationwide, pesticides were detected more frequently in community well systems as compared with rural domestic wells, but the concentrations of pesticides detected were lower in community wells than concentrations detected among rural domestic wells. Also, nitrate was detected more frequently and in higher concentration levels in rural domestic wells than community well systems.

Implications From The Survey
      The data indicate minimal concern at this time for pesticides present in CWS wells since there were no wells sampled that were above the Health Advisory Levels (HAL) established by EPA. Of all rural domestic wells sampled, 0.6% were above the HAL for pesticides, indicating a need to better educate rural well owners on how to prevent contamination. Data on nitrate contamination indicate a need to apply more stringent controls on solid waste disposal, as is currently occurring in community settings. Rural well owners as well as urban dwellers need to be informed of all nitrate contaminant sources and instructed on how to reduce or prevent nitrate contamination of their well water.

 Table 1. National Estimates For Number And Percent Of Wells For Pesticides And Nitrate.
 Estimated
Number		 Estimated
Percent
Pesticides
CWS* wells nationally with
one pesticide		 9,850 10.4
CWS wells above
MCL/HAL**		 0 0
Rural Domestic wells
nationally with at least
one pesticide		 446,000 4.2
Rural Domestic wells above
MCL/HAL**		 60,900 0.6
Nitrate
CWS wells nationally		 49,300 52.1
CWS wells above
MCL/HAL**		 1,130 1.2
Rural domestic wells
nationally		 5,990,000 57.0
Rural domestic wells above MCL/HAL** 254,000 2.4
*CWS = community water system

**The Maximum Contaminant Level (MCL) is the maximtnn permissible level of a contaminate in water that is delivered to any user of a public water system. MCLs are enforceable standards. Only pesticides with MCLs were included in estimating the number of wells containing pesticides above the MCLS. Although the MCL is not legally applicable to rural domestic wells, it was used as a standard of quality for drinking water. The Health Advisory Level (HAL) is the concentration of a contaminant in water that may be conswned over a person’s lifetime without harmful effects. HALs are non-enforceable, health-based guidelines that consider only non-cancer toxic effects. Only pesticides with HALs were included in estimating the number of wells containing pesticides above the HALS.

This publication was compiled from the results of a national pesticide survey conducted by the U.S. Environmental Protection Agency.

For more information, call your county Extension office. Look in your telephone directory under your county's name for the number.
Issued in furtherance of Cooperative Extension work in agriculture and home economics, Acts of May 8 and June 30, 1914, and other related acts, in cooperation with the U.S. Department of Agriculture. The Alabama Cooperative Extension System (Alabama A&M University and Auburn University) offers educational programs, materials, and equal opportunity employment to all people without regard to race, color, national origin, religion, sex, age, veteran status, or disability.

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