Pesticides:

EPA Could Do More to Minimize Groundwater Contamination

RCED-91-75: Published: Apr 29, 1991. Publicly Released: May 8, 1991.

Additional Materials:

Contact:

Peter F. Guerrero
(202) 512-4907
contact@gao.gov

 

Office of Public Affairs
(202) 512-4800
youngc1@gao.gov

Pursuant to a congressional request, GAO examined the Environmental Protection Agency's (EPA) efforts to: (1) assess pesticides' leaching potential in groundwater; (2) regulate those pesticides that could leach into groundwater; and (3) consider human exposure to pesticides in groundwater when setting and reviewing limits for pesticide residues in food.

GAO found that: (1) EPA made limited progress in assessing the leaching potential of the 16 pesticides it identified as groundwater contaminants in 1985; (2) 40 percent of EPA pesticide studies were unacceptable and may have to be redone, and it could be years before EPA has complete data to conduct comprehensive leaching assessments for those pesticides; (3) insufficient resources, staff shortages, low priorities, and ineffective policies addressing the potential for groundwater contamination contributed to the limited progress; (4) the EPA system for tracking data requirements and studies was unreliable; (5) EPA did not fully or consistently utilize the regulatory measures available to reduce groundwater contamination; (6) groundwater contamination was not among the specific criteria in the EPA regulation for initiating special reviews; (7) EPA plans to request that states develop management plans for pesticides that leach into groundwater; and (8) in setting and reviewing tolerances for pesticide residues in food, EPA did not routinely consider human exposure resulting from pesticides in groundwater.

Recommendations for Executive Action

  1. Status: Closed - Not Implemented

    Comments: EPA agrees that the tolerance system should consider exposure through food and water when both exposures are likely. EPA disagrees with the first method GAO recommended and believes that the second method recommended is in line with current agency practice.

    Recommendation: In order to ensure that total dietary exposure does not exceed safe levels, the Administrator, EPA, should, in setting and reviewing tolerances for pesticides found in groundwater or identified through studies as likely to leach into groundwater, assess and take into account potential human exposure from contaminated groundwater.

    Agency Affected: Environmental Protection Agency

  2. Status: Closed - Not Implemented

    Comments: EPA prefers to respond to concentrations posing significant risks rather than to respond to all detections through special reviews.

    Recommendation: During special reviews, EPA should consider risks to water resources resulting from groundwater contamination, and even if levels of a pesticide found in groundwater are well below the level currently considered to present a health risk, EPA should consider the pesticide's presence in groundwater to be a risk.

    Agency Affected: Environmental Protection Agency

  3. Status: Closed - Not Implemented

    Comments: EPA disagrees with the recommendation and prefers to address cases with groundwater contamination as the primary concern through state management plans.

    Recommendation: So that EPA can act preventively before contamination reaches potentially hazardous levels, the Administrator, EPA, should establish a criterion for initiating special reviews on the basis of pesticides' potential to contaminate groundwater.

    Agency Affected: Environmental Protection Agency

  4. Status: Closed - Implemented

    Comments: Some information can be conveyed on labels, and some information needs to be delivered through training. EPA and state extension services have prepared a training module for applicator certification. For the most serious threats, detailed state-level management programs will be needed. EPA has taken no further action and, therefore, the recommendation is being closed.

    Recommendation: To minimize further groundwater contamination, the Administrator, EPA, should, after acceptable data are obtained and reviewed, conduct a complete leaching assessment of pesticides with a potential to leach and provide specific information to applicators concerning the conditions that promote the leaching of those individual pesticides, including the soil characteristics and climatic conditions.

    Agency Affected: Environmental Protection Agency

  5. Status: Closed - Implemented

    Comments: EPA believes that well setbacks need to be applied on a chemical-specific and site-specific basis, either through reregistration decisions or state management plans.

    Recommendation: To help prevent groundwater contamination, the Administrator, EPA, should establish a pesticide's potential to leach or actual detection in groundwater as a criterion for requiring well setbacks.

    Agency Affected: Environmental Protection Agency

  6. Status: Closed - Implemented

    Comments: EPA does not support this recommendation but prefers to have the states identify the geographic areas of concern and devise specific, appropriate management measures.

    Recommendation: To help prevent groundwater contamination, the Administrator, EPA, should establish a percentage of the health advisory level as a criterion for prohibiting the use of a pesticide in any geographic area where the groundwater contamination from the normal agricultural use of that pesticide has reached that percentage.

    Agency Affected: Environmental Protection Agency

  7. Status: Closed - Not Implemented

    Comments: Groundwater advisories were previously added to about 12 pesticides. EPA recently contacted the registrants of four pesticides identified in the GAO report to discuss voluntarily adding groundwater advisories to those pesticides. EPA is evaluating general criteria for groundwater advisories to determine whether there are additional cases in which label statements can alert users to potential risks. Since EPA has not completed action and the recommendation is over 3 years old, GAO is deleting it from the open recommendations list.

    Recommendation: To help prevent groundwater contamination, the Administrator, EPA, should promptly require a groundwater advisory for all pesticides known to leach into groundwater from normal agricultural use to appear on labels under a prominent heading such as Groundwater Advisory, in order to alert the user to the problem.

    Agency Affected: Environmental Protection Agency

  8. Status: Closed - Implemented

    Comments: In the future, EPA will be reviewing key studies as they are submitted. List A pesticides are a priority for review.

    Recommendation: To facilitate EPA ability to assess the leaching potential of known groundwater contaminants, the Administrator, EPA, should review the relevant studies submitted by registrants for List-A pesticides, which include the 13 groundwater contaminants in this report, on a priority basis.

    Agency Affected: Environmental Protection Agency

 

Explore the full database of GAO's Open Recommendations »

Aug 15, 2016

Jul 26, 2016

Jul 21, 2016

Jul 14, 2016

Jul 7, 2016

Jun 14, 2016

Jun 13, 2016

Looking for more? Browse all our products here