Page 1 of 3 Jessica Poppe Q&A April 13, 2011

1. At what stage in the process is the reevaluation of atrazine at currently?

In 2010, EPA held three Federal Insecticide, Fungic ide, and Rodenticide Act (FIFRA) Scientific Advisor y Panel (SAP) meetings on human health issues related to atrazine. In February, EPA presented and sought scientific peer review of its proposed plan for incorporating epidemiology studies into the atrazine risk assessment. Later, in April, EPA pre sented and sought scientific peer review of its evaluation of atrazine effects based on experimenta l laboratory studies that will inform the selection of endpoints and safety factors in the risk assessment , and the sampling design used to monitor drinking water in community water systems. In September, EP A presented and sought scientific peer review of
its evaluation of atrazine non-cancer effects based on experimental laboratory studies and epidemiolog y studies. The September review was intended to incl ude any new experimental laboratory data since the April 2010 SAP meeting.

This summer, EPA plans to hold another SAP meeting concerning the Agricultural Health Study findings as well as epidemiology and laboratory animal studi es on atrazine. At the conclusion of this evaluati on of atrazine’s human health effects, EPA plans to as k the SAP to review atrazine’s potential effects on amphibians and aquatic ecosystems.

After this extensive review of atrazine, EPA plans to make any needed risk management decisions.
These decisions will be consistent with the science and our pesticide statutes.

2. Where there any studies or research in particular t hat prompted the reevaluation or are playing a particularly important role in the reeval uation?

EPA did not base its decision to formalize the re-e valuation process on the results of any one study. Over the last 8 years since the 2003 Atrazine Inter im Reregistration Eligibility Decision (IRED) was completed, significant atrazine research has been d one. Moreover, EPA has received an extensive amount of drinking water and ambient surface water monitoring data from the registrants of atrazine, as an ongoing condition of reregistration. As part of the 2010 SAP reviews, EPA evaluated close to 15 0 studies published since 2003 investigating a wide a rray of potential cancer and non-cancer effects relevant to human health risk assessment. If you a re interested in reading EPA’s reviews of these studies, as well as the meeting transcripts and the SAP’s recommendations, you may visit the Agency's 2010 SAP Meetings Web page, http://www.epa.gov/scipoly/sap/meetings/2010/index. html

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3. Does the EPA have an approximation for the number o f people exposed to concentrations of atrazine (maybe the population within the 1,172 wat ersheds with potential vulnerability)?

In its October 2003 Atrazine Interim Reregistration Eligibility Decision (IRED), EPA required the atra zine registrants to conduct watershed monitoring to ensu re protection of aquatic ecosystems. The watershed monitoring program was designed to focus initially on flowing water bodies in the most vulnerable watersheds associated with corn and sorg hum production. Monitoring occurred over a three-year period (2004 through 2006), and certain sites have had additional monitoring conducted from 2007-2010. During the initial sampling timefr ame, 40 watersheds were monitored which were statistically representative of 1,172 watersheds id entified as potentially vulnerable to atrazine expo sure based on atrazine use and runoff potential in these watersheds. The ambient streams associated withPage 2 of 3

these 1,172 watersheds are not drinking water sourc es. Protection of drinking water sources are considered separately under the Safe Drinking Water Act (SDWA) as well as the Office of Pesticide Programs’ (OPP’s) monitoring of atrazine in Communi ty Water Systems (CWSs).

With regard to SDWA, the number of public water sys tems reporting violations of the atrazine MCL in the United States in any given year between 2002 an d 2010 ranged from zero to 10. In fiscal year 2010

, only one public water system in the United States r eported a violation of the atrazine MCL. This publ ic water system is now purchasing its drinking water f rom another public water system.

With regard to the Office of Pesticide Programs’ (O PP’s) monitoring in CWSs, none of the CWSs in the monitoring program have exceeded OPP’s 37.5 ppb hum an health level of concern as a 90-day rolling average in raw water. Two exceedances of this leve l in raw water at a CWS in different years over a f iveyear period results in prohibition of further atraz ine use in the associated watershed. Additional information regarding the Office of Pesticides’ mon itoring in CWSs can be found at: http://www.epa.gov/opp00001/reregistration/atrazine /atrazine_update.htm

4. What groups do you think are most vulnerable to the health effects of atrazine?

Please refer to Sections 2, 3, and 4 of EPA’s Issue Paper for the September 14 - 17, 2010 FIFRA SAP Meeting located at www.regulations.gov docket number EPA-HQ-OPP-2010-0481-0030.

5. Is there any current information on the mechanism o f how atrazine might specifically affect pregnant women? Since atrazine seems to affect the hypothalamic pituitary axis, is it know what affect these changes could have on a fetus?

Please refer to Sections 2, 3, and 4 of EPA’s Issue Paper for the September 14 - 17, 2010 FIFRA SAP Meeting located at www.regulations.gov docket number EPA-HQ-OPP-2010-0481-0030.

6. Are there any pre-existing health conditions that a re known to possibly intensify the health effects of atrazine on any population?

Please refer to Sections 2, 3, and 4 of EPA’s Issue Paper for the September 14 - 17, 2010 FIFRA SAP Meeting located at www.regulations.gov docket number EPA-HQ-OPP-2010-0481-0030.

7. Has atrazine caused any major potential health effe cts outside of the reproductive or
endocrine systems?

Please refer to Sections 2, 3, and 4 of EPA’s Issue Paper for the September 14 - 17, 2010 FIFRA SAP Meeting located at www.regulations.gov docket number EPA-HQ-OPP-2010-0481-0030.

8. An additional question that I have, regarding the r isk management of atrazine in drinking water, is whether the EPA is involved in any health education practices in the communities
found with elevated levels of atrazine in their dri nking water?

EPA's approach to providing safe drinking water foc uses on addressing contamination before water reaches consumers, either by source water protectio n efforts such as those implemented through thePage 3 of 3

pesticide registration process or by setting drinki ng water standards for treated water from public wa ter utilities.

Under the Safe Drinking Water Act (SDWA), monitorin g and reporting requirements exist for the Maximum Contaminant Level (MCL) of 3 ppb, which is based on chronic exposure and is calculated against a running average from four quarterly sampl es. If any sample result taken for compliance purposes will cause the running annual average to e xceed the MCL at any sampling point, the system is out of compliance with the MCL immediately.

When a water system violates an MCL, the water syst em must notify the people who drink its water about the violation, what it means, and how they sh ould respond. Atrazine violations are reported in the Consumer Confidence Reports (CCRs) that water s ystems are required to provide their customers annually.

Under the EPA’s atrazine Interim Reregistration Eli gibility Decision and Memorandum of Agreement with atrazine registrants, the primary atrazine reg istrant provides EPA with monitoring data from the previous year that allows EPA to check for complian ce with the Office of Pesticides Program’s intermediate-term level of concern of 37.5 ppb, mea suring atrazine and its degradates in raw water. EPA uses the data to determine whether the Agency w ill allow continued use of atrazine in watersheds associated with the most vulnerable community water systems. Within a particular Community Water System, two exceedances of the 37.5 ppb level of co ncern in raw water, calculated as a 90 day rolling average, in two different years over a five-year pe riod results in prohibition of further atrazine use in the
associated watershed.

What types of control does the EPA endorse (at the source, along the path, and at a personal level) in order to limit the levels of atrazine exposure thro ugh drinking water?

Under its Safe Drinking Water Act authority and in order to limit the amount of atrazine allowed in finished drinking water that is served by public wa ter systems, EPA has established a national primary drinking water regulation (NPDWR) that specifies an enforceable Maximum Contaminant Level (MCL) of 3 ppb. As part of the NPDWR, public water systems are required to takes steps (i.e., monitoring and possibly treat) to ensure that the finished drinkin g water does not exceed the 3 ppb standard.

During the atrazine reregistration process in 2003, EPA felt that it was important to ensure the protection of raw drinking water – that is, water t hat had not yet been treated by drinking water utilities. Therefore, as part of atrazine’s reregi stration, EPA established a drinking water monitori ng program where raw water is monitored in water systems more likely to have higher seasonal atrazine contamination, and where exceedences in raw water trigger use prohibitions in the watershed of concern This raw water performance standard approac h makes the prevention of atrazine water contamination the responsibility of atrazine users rather than water treatment plant operators.

Since use prohibitions result from exceedences is i n raw, not finished water, the Agency believes ther e is a strong incentive for atrazine users and the regis trants to make every effort to prevent exceedences. Additionally, the public water utility’s monitoring and potential treatment of water to meet Safe Drinking Water Act standard of 3 ppb is more likely to prevent actual exposures above the Agency’s 37. 5 ppb intermediate-term level of concern for atrazine

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