Page 1 of 2 

Subject: CWS AMP & Frequency of Monitoring Meeting with Syngenta

Date/Time: December 15, 2010 – 1:30-2:00 PM 

Meeting Requestor: Syngenta 

Meeting Notes Preparer: Melanie Biscoe, EPA/OPP/PRD

Meeting Summary: 

During this meeting, Syngenta indicated that it will be sending a decommissioning 

request to EPA for 69 Community Water Systems (CWS) that have had 8 seasons of 

monitoring and will start the 9th season of monitoring in 2011 (see slide 2 in Syngenta’s 

associated slide set). Syngenta also indicated that it could voluntarily increase the 

frequency of monitoring in a select number of CWS, particularly focusing on 13 CWS 

that are flowing drinking water sources and therefore have lower dilution of atrazine 

compared to static water sources as well as higher variability in atrazine exposures. 

Syngenta thought that this may be useful for any model validation that EPA is doing in its 

frequency of monitoring work, or for acquiring additional statistical comfort in the 

Agency’s work. EPA indicated that it had not decided on whether it will be using 

modeling to determine peak exposures. EPA also indicated that more frequent data is 

always beneficial. EPA indicated that data collected during the 2011 growing season 

could not be analyzed in time for the 2011 SAP, but may be useful as EPA and the 

registrants think about the registration review that commences in 2013. EPA also noted 

that on slide 2 of Syngenta’s slide set that they list 88 CWS as being currently enrolled in 

the monitoring program, EPA’s count is 101; Syngenta and EPA discussed how this 

could be the result of multiple sampling measurements at individual CWSs, but that 

Syngenta and EPA should hold follow-up discussions to ensure that our lists of sampling 

sites are in agreement. 

Syngenta also discussed how it has been conducting other water quality measurements, 

such as turbidity, in other monitoring it is doing. Syngenta indicated that it would be able 

to conduct such additional measurements in a subset of AMP sites should EPA find such 

measurements helpful in understanding the watersheds and their water quality issues in a 

more comprehensive way. 

One EPA employee wanted some clarification on who conducts the monitoring and what 

the relationship is between Syngenta and that particular party. Syngenta explained that 

employees of the water systems themselves typically take the samples and send the 

samples directly to Syngenta for analysis by Adpen labs. Syngenta also indicated that 

some of the CWSs in the AMP have refused to participate in the AMP after 5 years of 

monitoring or as a result of increased scrutiny resulting from media inquiries; Syngenta 

indicated that in those circumstances it hires a third party to take the required samples. 

Note that on slide 5 of Syngenta’s slide set, the exposure values/rolling averages are for 

raw water, not water that has already gone through the treatment process. Also on slide 

5, samples from CWSs are only taken every 7 days and, as a result, Syngenta’s 4-day 

rolling average concentrations of atrazine were calculated using linear interpolation. 
Page 2 of 2 

Meeting Attendees: 

Janis McFarland Syngenta 

Dan Campbell Syngenta 

Melanie Biscoe PRD/OPP/EPA 

Nelson Thurman EFED/OPP/EPA 

Jack Arthur HED/OPP/EPA 

Dana Spatz EFED/OPP/EPA 

Don Brady EFED/OPP/EPA 

Mary Frankenberry EFED/OPP/EPA 

Anna Lowit HED/OPP/EPA