Who was involved in this special review evaluating atrazine impacts in Minnesota?

The MDA is the lead state agency for pesticide regulatory activities in Minnesota, and works with researchers at the Department of Health and the Pollution Control Agency to evaluate atrazine impacts. The Health Department assesses human health impacts based on applicable scientific data and develops drinking water guidance. The Pollution Control Agency assesses environmental impacts and establishes water quality standards for surface waters based on protecting human health and aquatic communities. 

What are the findings of the review?

While the review finds that atrazine regulations protect human health and the environment in Minnesota, it also identifies 10 opportunities for action to further minimize atrazine impacts. The review findings are posted at the MDA’s atrazine review webpage.

Are there any new regulatory requirements for atrazine as a result of the special registration review?

The state currently enforces requirements on the atrazine label regarding personal protective equipment, environmental hazard statements, and setbacks for mixing and loading, setbacks for wells and sinkholes, setbacks during application designed to protect surface water, and restrictions related to tiled farm fields. Since the review finds that atrazine regulations protect human health and the environment in Minnesota, it contains no specific new regulatory changes for atrazine. The state collected public comment on these findings until March 19, 2010. 

How does the MDA enforce the regulatory requirements on the atrazine label?

The MDA field inspectors annually conduct atrazine use inspections at application sites. These inspections have been conducted since 1990; however beginning in 2007 a focused effort has been underway to inspect atrazine application sites adjacent to water features. In 2007, the MDA conducted 83 application set-back inspections; 12% of these resulted in enforcement. In 2008, 79 inspections were conducted; 54 of those inspections involved sites where atrazine set-backs were required, there was a 26% violation rate. In 2009, 53 atrazine use inspections were conducted, 38 had site conditions requiring setbacks and 6 of those are under enforcement review. Enforcement actions on atrazine setback violations have ranged from a warning letter to a penalty of $500. Every enforcement case is evaluated on its own merits.

What is the review status of atrazine at the Environmental Protection Agency?

In October 2009, the U.S. Environmental Protection Agency (EPA) announced the launch of a new comprehensive evaluation of atrazine. During the first year of this new evaluation, EPA considered the potential for atrazine cancer and non-cancer effects, including data generated from laboratory animal and human epidemiology studies. As part of this evaluation, EPA sought advice from its independent Scientific Advisory Panel in a series of three meetings in 2010.  At the conclusion of this health effects evaluation, EPA asked the Scientific Advisory Panel to review atrazine’s potential effects on amphibians and aquatic ecosystems. For more information on the EPA review process, refer to the EPA's Atrazine - Background and Updates webpage

How are state agencies tracking emerging science on atrazine?

Emerging science is tracked through a variety of mechanisms, primarily by accessing available EPA science documents, consulting with EPA scientists through state-federal regulatory channels, and by consulting peer-reviewed and publicly available scientific literature. The agencies are committed to tracking emerging science to ensure that Minnesota’s health-based guidelines and environmental standards are scientifically sound. 

What is the MDA doing to prevent atrazine pollution in Minnesota?

Historically, atrazine has been frequently detected in Minnesota waters, leading to its designation as a groundwater “common detection” chemical under Minn. Stat. chapter 103H and a pesticide of concern for surface waters. As a result, atrazine receives heightened scrutiny in the form of monitoring, enforcement and applicator education programs. 

Atrazine is a Restricted Use Pesticide (RUP) and as such farmers need a special certification to purchase and apply it. Farmers can become recertified through ongoing education or testing by the University of Minnesota Extension Service. Dozens of workshops are conducted annually around the state to recertify applicators. Pesticide dealers selling atrazine must verify that applicators are properly licensed or certified at the time of pesticide delivery.

Current efforts to control atrazine leaching and runoff focus on implementation of existing prevention and mitigation measures. These measures include federal label restrictions, state label enforcement and the MDA’s atrazine-specific voluntary best-management practices.

Federal label changes and the state’s prevention, evaluation and mitigation measures have played important roles in protecting human health and the environment by reducing concentrations of atrazine in Minnesota’s water resources and preventing incidences of atrazine exposures above applicable health and environmental guidance. Efforts will continue in this regard. For more information about Minnesota’s efforts to minimize the impacts of atrazine and other pesticides, visit the MDA’s Voluntary Pesticide Best Management Practices webpage.

What are state agencies doing to track the presence of atrazine in water throughout Minnesota?

The presence of atrazine in public drinking water supplies is tracked through the Safe Drinking Water Act (SDWA) compliance monitoring program, serving approximately 80% of the state’s population. While private wells are not routinely regulated for contamination by any state agency, the MDA and the Department of Health, local units of government, and non-governmental organizations have conducted sampling of private wells through special projects. The MDA routinely monitors for atrazine and its chlorinated degradates in surface and groundwater water resources and provides monitoring results in a publically available annual report. The MDA has focused groundwater and spring monitoring in two areas considered particularly vulnerable to contamination: the central sand plains and the southeast karst region. Atrazine is also part of a long-term intensive surface water monitoring program that focuses on southeastern Minnesota and the Minnesota River Basin using automated samplers.

Should consumers of water from public or private drinking water supplies be encouraged to use home water filters?

Treating a home water supply is a matter of individual choice. Point-of use treatment devices such as an activated carbon filter or a reverse osmosis, which usually have activated carbon filters, can be effective in removing pesticides and their breakdown products, as well as other contaminants.  For any treatment unit to be effective, it must be properly maintained, and any filters must be replaced in a timely manner.

For consumers who receive drinking water from a municipal source, suppliers are required to test water quality and provide notification of contamination above levels of concern.

Detections of the parent atrazine compound in public water supply systems in Minnesota are rare and the Department of Health believes that based on current, available data, the current drinking water guideline of 3 ppb is protective of human health, including more vulnerable populations such as children or pregnant women.

For water supplies from private wells, the consumer is responsible for well testing and for monitoring drinking water safety. According to Department of Health, based on the entirety of available data from drinking water wells and groundwater monitoring wells, atrazine concentrations in private wells are expected to be absent or below established drinking water guidelines. Nevertheless, there is always a potential for atrazine contamination of drinking water in high atrazine use areas and geologically vulnerable areas.

Additional resources for testing and treatment:

Testing Private Drinking Water Wells

Home Water Treatment (Department of Health)

How can water consumers learn about atrazine test results in their water supply?

A public water supplier is required to monitor for atrazine according to a schedule as directed by the federal Safe Drinking Water Act, then provide an annual water quality report to consumers. Reports include information on the source of the system’s water along with results of testing done on the water during the previous calendar year. The Department of Health coordinates compliance and has the authority to ensure safe drinking water in all public drinking water supplies. Contact the Department of Health for additional information on detections of atrazine in public water supply systems.

Private drinking water supplies (i.e. private wells) are not routinely regulated for contamination by any state agency; however, state agencies, local units of government, and non-governmental organizations conduct sampling and analysis of private wells through special projects. Detections of atrazine in private water supplies typically occur in areas that have sandy soils and/or shallow water tables. Individuals participating in such surveys are always informed of their results.

Private well water testing is currently the responsibility of the well owner. Testing can be done through various private laboratories. The MDA along with the Department of Health continue to engage in education and outreach efforts to well owners in vulnerable areas to encourage well testing.

Are concentrations of atrazine in groundwater increasing or decreasing?

Groundwater monitoring data from monitoring wells, examined by the Department of Health and the MDA for the atrazine special registration review, indicate a historic decline in atrazine and its chlorinated degradates to concentrations below health-based guidance.  

What about atrazine concentrations in surface water?

Atrazine is detected often in streams around the state; however, exceedances of water quality standards have not lead to impairment listings. Surface water monitoring data examined by Pollution Control Agency and the MDA indicate that current atrazine concentrations are below state chronic standards, which protect all designated beneficial uses: aquatic plant and animal life and human use of waters for drinking and fishing. Assessing atrazine concentration patterns in surface water is challenging and depends on selecting appropriate locations, timing and frequency of sampling along with the number of samples per site. Concentration trends from peak exposure events or trends over time are also influenced by rainfall patterns relative to the time of application and changes in farming practices. 

For information about impacts from atrazine in surface waters, citizens can access the MDA monitoring reports and the Pollution Control Agency’s on-line water quality database.

Has there been an increase in the number acres receiving atrazine applications in Minnesota?

There is no reporting mechanism that allows the MDA to track the exact number of corn acres receiving atrazine. Between 2000 and 2009, an average of 7.5 million acres were planted to corn. At the same time, the MDA surveys of farmers throughout the state indicate that atrazine was used on an estimated 30% corn acres in 2003, 24% in 2005, and 22% in 2007. 

Why do Minnesota farmers choose to use atrazine?

Atrazine is an effective weed-control tool for corn production in Minnesota. It is one of the least expensive herbicides available and controls many different types of weeds (grasses and broadleaves) before or after corn is planted and emerges in the field.

Are there herbicide alternatives to atrazine?

There are no single active ingredient replacements for atrazine that offer both immediate and residual weed control for early season grass and broadleaf weeds. Rather, a combination of non-atrazine herbicide active ingredients would be required to achieve a similar level of weed control.  These combinations typically would add cost to farmers. 

What would happen if atrazine use was phased out or restricted in Minnesota?

From an environmental and human health standpoint, researchers generally know more about atrazine’s impacts than the impacts of pesticide alternatives. Therefore, it is not known what impacts might result if farmers switched to non-atrazine herbicide products. Because there are varying amounts of information on each alternative, it is difficult to quantitatively or qualitatively estimate the potential environmental impacts of alternatives.  From an economic standpoint, farmers switching to other more expensive pesticide options, or restricted from using atrazine in certain areas of the state, would face higher production costs and reduced profitability relative to competitors in other regions and states. 

Are there currently any atrazine impairment listings for water bodies in Minnesota?

Atrazine is detected often in streams around the state; however, the levels at which atrazine has been detected have not violated applicable water quality standards and therefore have not lead to impairment listings. 

Does atrazine cause cancer?

At the time of the review the Health Department concurred with EPA’s current classification of atrazine as “Not Likely to Be Carcinogenic to Humans.”

Does atrazine cause deformities in frogs and is it an endocrine disruptor?

It is not known precisely what causes frog deformities such as multiple or missing limbs. Atrazine has been a part of some studies exploring this issue, but a direct cause-and-effect relationship has yet to be established. Frog limb deformities were not considered as part of the Minnesota-specific review; however, in 2010, the EPA asked an independent Science Advisory Panel to review atrazine’s potential effects on amphibians and aquatic ecosystems.

Atrazine is an endocrine disruptor in mammals. Studies in rats have indicated exposure to atrazine or its degradates can lead to changes in the reproductive cycle in adult females and to developmental delays and other endocrine impacts in offspring. How these effects might apply to humans is not well understood and much more research is needed.

Atrazine’s role as an endocrine disruptor in amphibians (like frogs) and amphibian populations has been an issue of significant scientific inquiry. The Pollution Control Agency has been closely following EPA scientific reviews and other scientific literature about amphibian exposure to atrazine.  However an extensive evaluation of the literature to assess endocrine disruption was not completed for this registration review because this area is under review by the EPA. The EPA’s Endocrine Disruptor Screening Program is poised to provide data needed to more accurately assess endocrine disruption.