June 2008-November 2010 Meeting Log for Atrazine Special Review Docket 

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March 5, 2009, 1-1:30 PM 

EPA/OPP conference call with Syngenta regarding Atrazine Monitoring Program (AMP) 

data. 

The purpose of this conference call was to explain to Syngenta how data are used to 

calculate Margins of Exposure (MOEs) for Community Water Systems (CWSs) in the 

Atrazine Monitoring Program (AMP). 

Calculation of the MOE uses actual atrazine, simazine, and 3 atrazine metabolite 

measurements from finished water. These measurements are added together and 

converted to parts per million (ppm). The data from sampling are scattered throughout 

the year, but calandex requires daily residue levels to calculate an MOE. Because of this, 

daily residue levels are calculated using linear interpolation between the data points. 

Prior to 2006, some of the data points are sparse. This is because EPA/OPP’s 

Environmental Fate and Effects Division (EFED) used only total chlorotriazine (TCT) 

data, rather than using more prolific atrazine data from immunoassays to calculate TCT 

levels via a regression equation. This approach is consistent with the approach in the 

2006 Triazine Cumulative Risk Assessment. EFED examined the data to ensure that the 

data interpolations between points were not substantially overestimating residue levels. 

There was only one CWS (Westport) in which this could have posed a problem. 

Once EPA interpolates the data, the data can be run through calandex. The calandex 

model first calculates the 90-day rolling averages, then multiplies this value with the 

consumption data from CSFI, and compares the result to an endpoint of 1.8. Calandex 

does this ten times and then the average of the ten repetitions is used as the final MOE. 

For all non-detect samples EPA assumed that half the Limit of Quantification (LOQ) was 

present. 

Levels of 9-12 ppm in 90-day averages tend to have an MOE below 300. 

Discussion about data from specific CWSs: 

• Aqua, IL – discussed the number and type of samples we have, and which were 

used for the MOE calculation. 

• Piqua Gravel Pit should be raw-water only. Are we running finished or raw data 

for Piqua Gravel Pit, or is it a copy-paste error? 

• Vermont—do we have the TCT data for it for 2007? 

• Hettick – Syngenta has documentation from Hettick’s Drinking Water Watch 

Website that says the source switched. Is that documentation OK? We’ll confirm 

with Bob. Syngenta will check the SDWA data to make sure the states aren’t 

monitoring in Hettick—if they are, that means that its community switched back 

to its original drinking water source. 

• EPA provided the names of systems with MOEs below 300 for year 2003 to 
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Syngenta. 

Participants: 

Melanie Biscoe, PRD/OPP/EPA 

Nader Tadayon, HED/OPP/EPA 

Mary Frankenberry, EFED/OPP/EPA 

Jack Arthur, HED/OPP/EPA 

Anne Overstreet, PRD/OPP/EPA 

Brian Christiansen, Syngenta (on phone) 

Paul Hendley, Syngenta (on phone) 

Dan Campbell, Syngenta (on phone) 

Ron Williams, Syngenta (on phone) 

Andrew Merritt, Syngenta (on phone) 

Meeting notes prepared by – Melanie Biscoe 

November 20, 2009, 10-11 AM 

EPA/OPP meeting with Alan Roberson of American Water Works Association 

(AWWA). 

Alan Roberson requested this meeting 

OPP and AWWA discuss the possibility of monitoring for peaks through the Atrazine 

Monitoring Program (AMP). AWWA indicates that it has worked with a statistician on 

this and can present it to EPA. 

AWWA indicated it was interested in learning what the results would be of OW’s 6-year 

review of the atrazine MCL. 

OPP asked AWWA about its perspective on disseminating atrazine monitoring data to the 

public. AWWA indicated it would be supportive of a compromise that could work. 

AWWA indicated that a select few chemicals require more monitoring under SDWA if 

they exceed half of the MCL, and that from the regulatory perspective that may be an 

option (although it is not AWWA’s position to support this as a measure per se). 

OPP and AWWA discussed issues surrounding provision of data to the public, including 

whether fears are raised by releasing data, right-to-know issues, and differentiating 

between raw and finished water data. 

OPP asked AWWA how people respond to media articles and reports like those 

published on atrazine. AWWA indicated that there has been a similar situation occurring 

with pharmaceuticals in drinking water. AWWA indicated that Community Water 

Systems (CWSs) are getting few calls from consumers compared to calls from political 

figures and newspapers. (AWWA discussed how its sister organization, Water Research 

Foundation, has been conducting research on this issue). AWWA also indicated that, 
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from its perspective, the news cycle in the Midwest took its course and there wasn’t 

substantial impact of the news reports concerning atrazine. 

OPP asks AWWA whether it thinks OPP is missing systems through the current trigger 

for CWSs to enter the AMP. AWWA indicates that it’s possible but really unlikely that 

EPA is missing systems. 

AWWA asked OPP about the atrazine re-evaluation. OPP indicated that it will be 

conducting a re-evaluation of the science underlying atrazine regulation for human health 

with no prejudged outcomes. OPP indicated that after the human health evaluation is 

complete, ecosystem issues will undergo review. OPP discussed how the atrazine reevaluation would utilize the SAP. OPP also mentioned that registration review for 

atrazine would commence in 2013. 

OPP indicated that AWWA’s perspective on the impact of atrazine alternatives on 

drinking water and CWSs would be valuable. 

Meeting notes prepared by – Melanie Biscoe 

Participants: 

Melanie Biscoe, PRD/OPP/EPA 

Robert McNally, PRD/OPP/EPA 

Eric Olson, PRD/OPP/EPA 

Alan Roberson, American Water Works Association (AWWA) 

December 4, 2009, 1-2 PM 

EPA conversation with stakeholders on providing atrazine drinking water monitoring 

data. 

EPA requested this conference call. 

OPP discussed the purpose of the conference call, which was to acquire stakeholder input 

to explore better ways to inform the public more quickly about results of atrazine 

drinking water monitoring, with particular focus on FIFRA-required monitoring 

conducted by Syngenta Crop Protection under the Office of Pesticide Programs’ Atrazine 

Monitoring Program (AMP). 

Natural Resources Defense Council (NRDC) discussed how consumers should have 

timely notification of seasonal spikes of atrazine occurring in drinking water in the 

Midwest. They indicated that it is important for consumers to be able to access the data 

as they come out. 

Triazine Network wanted NRDC to clarify whether it thinks the Community Water 

Systems (CWS) or the public (or both) ought to be notified of the atrazine levels; NRDC 

indicated that it would depend on who is doing the notification, but that ultimately the 

water consumers themselves hould be able to access the information. Triazine Network 
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indicated that atrazine levels cannot be tested in a 24-hour timeframe, and that there are 

logistical issues in getting the data analyzed. 

American Water Works Association (AWWA) said that in terms of getting the atrazine 

drinking water data out in a timely manner, there isn’t really a mechanism to do this, 

particularly in terms of a media outlet. This would be the case even if a spike lasts for 

two weeks. NRDC responded that the internet could be used as an outlet – that the 

information doesn’t have to be put out on every broadcast. Consumers deserve the right 

to know what is in their water so they can choose to filter it. 

Triazine Network said that there are lots of contaminants that have spikes below levels of 

concern, and wondered why there was so much of a focus on atrazine. NRDC indicated 

that it would gladly have other contaminant data where levels are below levels of 

concern, but today the topic is atrazine. NRDC discussed how USGS has water monitor 

gages active all the time and that you can look at data history, averages, or graphs. 

AWWA expressed its support for having all of Syngenta’s data available but indicated 

that there could be issues regarding how the water systems feel about providing this 

information if the burden is on the water systems themselves to provide it. 

OPP discussed the protocol for the data as it stands right now, and that CWS have access 

to it as soon as it’s available. EPA added that QA/QC for data as it comes in would add a 

couple weeks to posting on the internet. OPP discussed how there’s no way to get data in 

a 24 hour period. OPP also said that Syngenta required to notify EPA w/in 30 days if 

there is an exceedence of the 90-day Level of Concern (LOC) in raw water. OPP asked 

for thoughts on annual posting of the monitoring data. 

Triazine Network and AWWA discussed how the turn-around time to meet a need for 

instantaneous data would be a week or two at a minimum. 

NRDC talked about need to present actual numbers, and that otherwise it would make 

EPA look like it’s hiding information. NRDC discussed its belief that there is a sperm 

motility issue at 10 days of atrazine exposure, so quick turnaround of the data is 

important. In addition, NRDC discussed how it wants to see raw data, explanation and 

context for levels of concern, and rolling average calculations all publicly available. 

NRDC cited NHANES data as an example where you’d have graphs, summary data and 

raw data put into context. AWWA indicated that NRDC’s proposal would be fine under 

the AMP, but not appropriate for SDWA quarterly samples. 

Triazine Network objected to notion that atrazine is the contaminant of most concern in 

drinking water, as suggested in this discussion. Triazine Network indicated that the 

LOCs an individual may perceive have not been vetted through the regulatory community 

and would not warrant a weekly monitoring update. 

Triazine Network also discussed its belief that it’s well established what the application 

season is, and that people would know about the seasonal increases during application 
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times. The public has the ability to deal with this even in the absence of data. Triazine 

Network said that it is questionable whether the data would really provide added value to 

people. 

Triazine Network was also concerned about how water systems would react to data 

provisions. Triazine Network indicated that CWSs may drop out of the AMP because it 

puts an additional burden on the system in terms of the effort to monitor as well as the 

scrutiny from the media. Triazine Network indicated that there is a potential for CWS to 

quit the AMP en mass, and said that it knows CWSs that aren’t participating in the AMP 

because of the potential for increased scrutiny. 

OPP asked whether CWSs are concerned about monitoring data being put on the web 

more frequently or about making information on CWS locations public. Triazine 

Network indicated that it had heard from several CWSs that do not conduct monitoring 

for the AMP because of the SDWA monitoring they’re already doing. AWWA indicated 

that it had talked with Syngenta earlier in the week, and that Syngenta is trying to get 

more information about the perspectives of the water systems on this. 

OPP asked whether frequent reporting was equivalent to frequent scrutiny. AWWA 

indicated that it’s more the issue of putting the LOC into context – providing risk 

communication along with the numbers. Triazine Network said that the presence of data 

is not the issue; rather, it’s the issue of the Agency providing proper risk communication. 

Triazine Network indicated that with the recent New York Times article there was a 

distinct lack of risk communication in the reporting, and believed that a lot of heightened 

concern about risks would not have been raised if the risk communication piece had been 

in place. Triazine Network did not believe that the issue was about the data being 

available more often. 

EPA asked how the stakeholders define a “spike” in atrazine levels. Triazine Network 

discussed how atrazine levels are, generally, higher in May than in any other time of year. 

NRDC described its perspective on spikes as atrazine levels that go from below 1 ppb on 

average to 10, 12 and 20 ppb on average, which mainly occurs in the spring. 

OPP discussed how if there’s no question that there are higher levels of atrazine after use 

historically, providing information to people may be useful but if people know it spikes 

in the spring they may just buy filters anyway. Triazine Network and AWWA agreed 

with this. NRDC indicated that there may be systems that didn’t historically show 

problems that could be a problem, and that it would be valuable to have data on those 

particular systems. 

AWWA indicated that the turnaround time for analyzing a sample is 2 weeks, per its 

prior communication with Sygnenta. NRDC discussed how having timely data during 

spring and summer is important, and that one would not need immediate information on 

atrazine concentrations during other times of year. NRDC indicated that in spring and 

summer one would want to shorten that 2-week turnaround time for analysis. OPP 

indicated that it could look into whether the logistics can be sped up. 
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OPP said that it currently makes information/data available on its Atrazine Updates 

website, and asks whether stakeholders believe there are other ways EPA could make the 

data accessible. AWWA indicated that you would really have to rely on the systems 

involved, but not all of them have websites or email. 

OPP asked how comfortable stakeholders would you feel if the data were not QA/QCed 

by EPA before posting. AWWA indicated that it would be concerned if the raw data 

were not QA/QCed by the laboratory and Syngenta. NRDC indicated that it didn’t want 

the data posted without a QA/QC, and asked what the steps are for a QA/QC. OPP 

explained the difference between the Syngenta and OPP QA/QC process. NRDC stated 

that it was comfortable with OPP posting AMP data without QA/QC by OPP’s 

Environmental Fate and Effects Division. 

OPP asked stakeholders whether they believed that the public was aware of the atrazine 

data on the Atrazine Updates website. Triazine Network said that, in rural America, not a 

lot of people are looking for information on a particular contaminant. Triazine Network 

said that if people think there is an issue, they believe that the contaminant would be 

regulated and reported accordingly, and that they are not going to be looking for these 

data. NRDC indicated that it gets calls from people in small towns about contaminants. 

NRDC said that when they ge these calls, they tell people to talk directly with their CWS 

and to contact EPA. Triazine Network said it believed that NRDC received those calls as 

a result of the “Poisoning the Well” report it issued regarding atrazine. 

Meeting notes prepared by – Melanie Biscoe 

Participants: 

Robert McNally – EPA/OPP 

Eric Olson – EPA/OPP 

Melanie Biscoe – EPA/OPP 

Eric Burneson – EPA/OW (on phone) 

Francine St.-Denis – EPA/OW (on phone) 

Alan Roberson – American Water Works Association (AWWA) (on phone) 

Jennifer Sass – Natural Resources Defense Council (NRDC) (on phone) 

Mae Wu – Natural Resources Defense Council (NRDC) (on phone) 

Jere White – Triazine Network (on phone) 

Tyler Wegmeyer – American Farm Bureau Federation (on phone) 

January 6, 2010, 10-11:30 AM 

Meeting with American Water Works Association (AWWA) on Frequency of Monitoring

AWWA offered to present its work on frequency of monitoring to EPA, and OPP 

accepted this offer. 

In addition to the power point presented by Jeff Rosen of Clancy Environmental 
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Consultants (CEC), which is also posted in docket number EPA-HQ-OPP-2004-0319, the 

following items were discussed: 

• The percentile used not being the absolute maximum 

• The possibility of monitoring something orthogonal to the data to inform 

sampling times 

• Breaking down sampling plans based on the history in an individual watershed 

• Thinking about how many of the Community Water Systems (CWSs) in the 

Atrazine Monitoring Program (AMP) use carbon filtration vs. those that do not 

• The cost of monitoring – approximately $100 per sample analyzed using Gas 

Chromatography/Mass Spectrometry (GC/MS), not including the “burden” cost 

on of someone physically collecting the sample and sending it to the lab. 

• Syngenta providing AWWA with data from the AMP (which they had already 

done) 

AWWA mentioned that it had developed a analytical tool that may be useful for EPA in 

its frequency of monitoring evaluation, and that it is free for anyone to use. AWWA also 

offered to do conduct additional analyses based on EPA feedback. OPP thought it might 

be valuable to look at upper percentiles for a 3-4 day average. 

Meeting notes prepared by – Melanie Biscoe 

Participants: 

Dana Spatz, EPA/OPP/EFED 

Mike Messner, EPA/OW 

Wynne Miller, EPA/OW 

Mary Frankenberry, EPA/OPP/EFED 

Nelson Thurman, EPA/OPP/EFED 

Melanie Biscoe, EPA/OPP/PRD 

Elizabeth Mendez, EPA/OPP/HED 

David Miller, EPA/OPP/HED 

Jack Arthur, EPA/OPP/HED 

Nader Tadayon, EPA/OPP/HED 

Steve Nako, EPA/OPP/HED 

Aaron Niman, EPA/OPP/HED 

Alan Roberson, American Water Works Association (AWWA) 

Jeff Rosen, Clancy Environmental Consultants (CEC) 

Anna Lowit, EPA/OPP/HED 

David Hrdy, EPA/OPP/HED 

Russell Erickson EPA/ORD (on phone) 

November 30, 2010, 11:30 AM-12:30 PM 

Call with Wisconsin State to discuss details about their atrazine restrictions for 

groundwater protection. 

EPA/OPP requested the conference call. 
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Wisconsin state officials discussed the timing and rationale for the atrazine restriction 

program in Wisconsin, which has been in effect for twenty years. They discussed how 

there are now 101 prohibition areas covering approximately 1.1 million acres of 

Wisconsin, impacting less than 10% of the 3.5-4 million acres of corn in Wisconsin. 

EPA asked whether there were atrazine management areas with restrictions short of 

prohibition. Wisconsin state officials indicated that there had been a number of atrazine 

management areas triggered by monitoring results from private wells, but that there were 

so many of these areas that in 1993 the entire state of Wisconsin reduced atrazine rates 

state-wide, effectively making all of Wisconsin an atrazine management area. 

Wisconsin state officials noted that Wisconsin’s groundwater law requires prohibition of 

the use of a contaminant that has exceeded a state enforcement standard unless someone 

can prove that a measure short of prohibition is effective. To-date, no one has shown that 

a lesser measure is effective in atrazine prohibition areas. 

Wisconsin state officials discussed how they had considered rolling back atrazine 

prohibition areas; however, even at reduced rates there were still exceedences of 3 parts 

per billion in monitoring wells, so reintroduction of atrazine into prohibition areas was 

not considered an option. 

Wisconsin state officials indicated that groundwater quality in prohibition areas is greatly 

improving. Every year they continue to look and see if new/expanded prohibition areas 

needed. Periodic expansion of prohibition areas does occur, but in general Wisconsin is 

not finding whole new areas where prohibition would be proposed. 

EPA asked whether the reduced rates are effective for target pests. Wisconsin state 

officials indicated that the reduced rates of atrazine are effective for broadleaf weeds, but 

not grasses. They discussed how the National Agricultural Statistics Service (NASS) is 

conducting a survey of growers to look at the impact of the prohibition areas on growers. 

They discussed some of the preliminary results of this survey, and indicated that the final 

report would be available in January or February. 

EPA was interested to know what the population of growers and numbers of corn acres 

were in the prohibition areas. Wisconsin state officials discussed how the farm sizes vary 

dramatically. They also indicated that corn is grown on both livestock farms and farms 

that just grow cash crops (generally on a corn and soybean rotation). 

EPA also asked what the primary alternatives are for atrazine in prohibition areas. 

Wisconsin state officials indicated that glyphosate the primary alternative, and that it 

does not pose groundwater concerns. Simazine had been used as an alternative in one 

area, but the simazine metabolites contaminated the groundwater and the state had to 

prohibit the use of atrazine as well as simazine in that area. (Because the area was so 

small with so few growers, the state had individual agreements and administrative orders 

with those growers to stop use of simazine in that area). Wisconsin indicated that 
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mesotrione is also an alternative to atrazine in these areas, but they are not aware of any 

groundwater concerns for this chemical or other alternatives used for broadleaf weed 

control. Wisconsin officials indicated that metolachlor and acetochlor are used for 

control of grassy weeds and that they are both seen in groundwater but not at levels 

where the state would take action to prohibit use. 

EPA wanted to know whether farmers were going out of farming or growing less corn as 

a result of the prohibition areas. Wisconsin indicated that to-date, there has not been 

evidence that farmers in prohibition areas are growing less corn or going out of farming. 

In fact Dane County, which has about two-thirds of its land in an atrazine prohibition 

area, remains one of the top corn producing counties in the state. 

EPA asked about ecological concerns due to atrazine use in the state. Wisconsin 

indicated that there are no impaired waters in Wisconsin specific to pesticide use, 

although there are not the same standards for surface waters in Wisconsin as there are for 

groundwater. The Wisconsin Department of Natural Resources does conduct monitoring 

of pesticides and detects them at various levels in groundwater and surface water, but 

there have not been detections at levels where the state would take action. 

Wisconsin officials described how they conducted their investigations to expand the 

boundaries of a prohibition area. They indicated that when a particular well sample 

exceeds the 3 part per billion standard, the state collects confirmation samples within a 

one-mile radius around that particular well. They then determine whether the well 

contamination is from field use, a spill, or some kind of backflow event. The state 

conducts interviews and collects atrazine use records for the previous five years within 

the one-mile radius of the well. When it is determined that there were no point sources 

for the contamination, the state proceeds with proposing the expansion of the prohibition 

area. They’ve found generally that well contamination is correlated with atrazine use 

intensity. 

EPA asked whether there are compliance issues in prohibition areas. Wisconsin officials 

indicated that there are some compliance issues, and that they conduct soil tests, observe 

applications, and check dealer records to prevent use in the prohibition areas. They 

indicated that occasionally the use in prohibition areas is intentional, but sometimes 

growers buy pre-mix products and don’t realize that the pre-mix contains atrazine. In 

general, however, Wisconsin believed that overall compliance is pretty good, as 

evidenced by decreased levels of atrazine in the groundwater monitored in the prohibition 

areas. 

EPA wanted to know what stakeholder responses have been to prohibition area proposals. 

Wisconsin officials indicated that there has been more stakeholder comment than usual, 

in part due to EPA’s scientific evaluation of the human health effects of atrazine 

announced in October 2009. In prior years, however, no one would show up to 

stakeholder meetings, with the exception of when the prohibition areas were initially 

created in the early 1990s. Wisconsin officials indicated that growers would attend 

public meetings, but property owners with contaminated wells would attend public 
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meetings in support of creating the prohibition areas. 

EPA wanted to know whether well construction was considered an issue with regard to 

atrazine contamination. Wisconsin officials indicated that well depth is not a good 

predictor of atrazine levels in a well, and that the most important variable in 

contamination is intensity of use. 

EPA was interested in having the grower survey mentioned earlier in the discussion, and 

Wisconsin officials offered to provide it when it became available. 

Meeting notes prepared by – Melanie Biscoe 

Participants: 

Anne Overstreet, EPA/OPP/PRD 

Melanie Biscoe, EPA/OPP/PRD 

Peter Caulkins, EPA/OPP 

Nelson Thurman, EPA/OPP/EFED 

Bill Chism, EPA/OPP/BEAD 

Bill Phillips, EPA/OPP/BEAD 

David Donaldson, EPA/OPP/BEAD 

Timothy Kiely, EPA/OPP/BEAD 

Jonathan Becker, EPA/OPP/BEAD 

Jeff Postle, Wisconsin Department of Agriculture, Trade and Consumer Protection (on 

phone) 

Jim Vanden Brook, Wisconsin Department of Agriculture, Trade and Consumer 

Protection (on phone) 

Lori Bowman, Wisconsin Department of Agriculture, Trade and Consumer Protection 

(on phone)