Atrazine: Potential MOA Revisions 

Discussion with Technical Registrants 

October 26, 2009 

2:30 – 4:30 p.m. EDT 

Conference Call Requested By: EPA Office of Pesticide Programs

Participants: 

 

Office of Pesticide Programs, EPA – Richard Keigwin, Robert McNally, Eric Olson, Melanie 

Biscoe, Catherine Eiden 

Atrazine Technical Registrants – 

SYNGENTA 

Janis McFarland 

Dan Campbell 

AGAN CHEM MFG, LTD 

MAKHTESHIM-AGAN OF NORTH AMERICA INC 

Ephi Gur 

Leanne Pruett 

DREXEL CHEMICAL COMPANY 

Roy Olson 

OXON ITALIA S.P.A. 

SIPCAM AGRO USA, INC 

Joe Burley 

Meeting Notes 

 

Introductions

Meeting participants introduced themselves. EPA indicated that the meeting notes would be 

placed in the atrazine Special Review docket within 10 days of the call. 

General Comments and Questions from Registrants

Registrants indicated that they are troubled about the atrazine re-evaluation being rolled out over 

the next year, primarily because they believe this process deviates from the process that had 

already been established and is based on the [“Poisoning the Well”] NRDC report and 

subsequent media coverage on atrazine. Registrants indicated that they looked forward to 

hearing the Agency’s rationale for proposed changes to the MOA. Registrants felt that this 

meeting was forced, and felt rushed in attending. 
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EPA indicated that it understood the registrants concerns, and then recapped the previous call 

with registrants on October 7, 2009, which was an informational call to alert the registrants to the 

SAPs scheduled for FY 2010 (during which the Agency proposed a future meeting with 

registrants to discuss potential changes to the MOA). The Agency indicated that it felt that the 

proposed changes to the MOA were pragmatic and easy to do, and would help address public 

concern over atrazine. 

Registrants asked if the Agency was also going to discuss these negotiations with the public 

more broadly. EPA indicated that the Agency has not discussed these negotiations with other 

parties, as the MOA involves an agreement between EPA and the atrazine registrants 

exclusively. 

Discussion of Potential MOA Modifications:

1. Providing drinking water monitoring data to the public more quickly. 

EPA indicated that members of the public are interested in knowing what is in their drinking 

water as soon as is reasonably possible. The Agency asked registrants how long it would take to 

provide data to the Agency or the public, given the time it takes to analyze the samples. 

Registrants then described each step of the monitoring process: 

1. Sample taken at the CWS 

2. Sample shipped directly to lab for analysis 

3. Results of analysis provided on a secure computer webpage to Syngenta and the CWS 

itself 

4. Syngenta sends fax to CWS when data are available on the secure webpage 

Registrants indicated that, on average, it takes about 10 days to receive sample results after the 

sample is taken. 

Registrants are concerned, however, that (similar to a situation that happened with Alachlor) 

some CWS will refuse to collect samples for the FIFRA-required monitoring program because of 

the fear it may cause within the community if the data is misinterpreted by interest groups. 

Registrants said that, prior to 2009, only summary data were provided on the EPA website and 

not raw data (although, as the Agency noted, anyone could FOIA the raw data) and that the data 

were identifiable only by county, and not by water system. Registrants indicated that making the 

database public would compromise the ability of the registrants to have an effective monitoring 

program. Syngenta has talked with all the CWS in the FIFRA-required monitoring program 

since the August 22, 2009 New York Times article including those CWS mentioned by name in 

the New York Times article. 

Registrants indicated that, at the time of this meeting, they were not in a position to say what 

they could or could not live with in terms of an agreement on the frequency with which the 

monitoring data is shared with the public. 
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Registrants indicated that the Agency’s knee-jerk reaction to the recent reports and articles 

(before it even reviews the NRDC report) would just raise the public’s concerns about atrazine. 

2. Monitoring to capture peak, single-day exposures in Community Water Systems. 

EPA indicated that the public is concerned that there may be high single-day spikes of public 

health consequence that currently are not being captured through the existing monitoring 

program. EPA would like to know if registrants have any monitoring data that demonstrates how 

current monitoring may be capturing highs and lows; this information would also be useful for 

the 2010 atrazine SAPs. The Agency suggested that if the registrants do not have these data, that 

additional daily samples could be gathered in some CWS. 

Syngenta said that it has 400,000 atrazine samples in its databases, and that none of them have 

ever exceeded the 298 ppb acute drinking water level of concern or the 37.5 ppb 90-day rolling 

average level of concern. Syngenta indicated that most of those samples were taken during the 

season of highest atrazine use. Additionally, Syngenta indicated that some of their studies 

include daily monitoring (however, daily monitoring is not currently conducted in any CWS). 

Syngenta has initiated a statistical examination of its sample databases and will inform the 

Agency on any mathematical modeling they do that indicates peaks are adequately captured. 

3. Establishing a performance standard for the 298 ppb one-day drinking water level of concern 

established in the Atrazine RED. 

EPA explained how the public may believe that the Agency is not protecting against one-day 

spikes of atrazine. Given that drinking water monitoring data have not exceeded the 298 ppb 

acute drinking water level of concern, the Agency expressed its belief that establishing this 

standard in the MOA would be relatively innocuous. 

Registrants stated that establishment of a one-day regulatory parameter is out of step with what 

EPA requires for other chemicals, especially when it is known that the chronic MCL is protective 

of acute exposures. Registrants indicated that they will bring more information on this to the 

next MOA meeting on November 3, 2009. 

The Agency noted that the Office of Water sets one- to ten-day health advisories. 

Registrants expressed concern that the Agency would set a precedent of establishing a one-day 

regulatory standard when there is no scientific reason for this standard to be established (since 

Syngenta’s extensive monitoring database shows that none of the samples exceeded 298 ppb). 

The registrants were concerned that setting this standard would send a message to the public that 

current atrazine monitoring misses peaks when that is not the case. 

The Agency responded that it wants to provide the public with a sense that the Agency is being 

responsible and watchful. 

Registrants discuss how the Canadian acute level of concern for atrazine is 1200 ppb. 
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4. Prohibiting atrazine use in the watershed after one exceedence of the 37.5 ppb 90-day rolling 

average. 

EPA indicated that the public may believe that the Agency is not protective enough by allowing 

two exceedences of the 37.5 ppb 90-day rolling average in raw water used by CWS. The 

Agency said it would like to revise this standard such that atrazine could not be used in a 

watershed after one exceedence of the 37.5 ppb 90-day rolling average in raw water used by 

CWS. 

Registrants said that 90-day rolling averages above 37.5 ppb are safe, given the safety margins 

included in the level of concern. Registrants were concerned that there is no scientific basis for 

this regulatory change and that this type of regulation would be unprecedented in any type of 

monitoring and mitigation program. The registrants also indicated that it would be acceptable to 

have two exceedences of this level in raw water, because raw water is not consumed by the 

public. The registrants indicated that the underlying toxicological study in rats was appropriately 

conservative and was a 6 month exposure study. As a result it would be unlikely to see the 

intermediate-term health effect in humans after a 90-day exposure. 

EPA explained that there is uncertainty surrounding the amount of time required to elicit the 

intermediate-term human health effect. Effects in the 6 month study were seen after 4-5 months 

of exposure and the Agency has no reason to believe that a human response to dosing would be 

any longer than the 4-5 month period. EPA indicated that this is why the Agency believes that 

mitigation measures should be implemented after 1 exceedence and not 2, as is currently 

required in the MOA. 

The registrants indicated that they would gather additional information, look into other studies 

that they have so we can discuss this issue further on the November 3, 2009 MOA meeting. 

Next Steps & Wrap-Up

EPA opened the discussion to any additional general comments, but none of the meeting 

participants had additional comments. 

EPA discussed the plan to meet on November 3, 2009, and indicated that this would be the last 

meeting on the topic of drinking water in the MOA. Registrants asked why this would be the 

final meeting on this topic; EPA indicated that this is a fairly straight-forward issue, and that 

these meetings are not to debate the levels of concern already established in the Agency’s risk 

assessments, but to change the MOA based on already-established levels of concern. The 

Agency expressed a willingness to consider future meetings, but only if there was a reason to do 

so. 

Next Meeting: November 3, 2009 2-4 PM 

Meeting Notes Prepared by: Robert McNally