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### Atrazine Focus Meeting July 25 2013 July 25 , 2013

Slides enclosed for following agenda items
● Agricultural and non-agricultural use sites, clarification of non-ag use sites; (fallow, hay, pasture, forests, turf, conservation reserve program) ● Other label clarification/harmonization ● Brief overview of stewardship programs ● Topics for future discussion

2 ● Additional data to be submitted

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# Atrazine Use Sites A table summarizing all atrazine labeled uses is being

prepared. Draft copies are provided. Intended to include all uses from the technical registrants ’ atrazine end use labels

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## atrazine end use labels Use and Survey information 

# Example of Areas For Label Clarification/Harmonization ● Fallow Uses CRP P t H ● CRP , P as t ures, H ay

- For establishing grasses, grazing/haying prohibition ● Roadsides, Rights-of-Way (lumber yards, ...) ● Conifers / Forestr y

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# Statements in EPA Label Data Report for Atrazine and Problem Formulation for Environmental Fate and Ecolological Risk Assessment for Atrazine ● Some listed rates appear to be incorrect ● Some listed use sites are not on current labels

- i.e. soybean, wheat, oats – there are fallow uses after harvesting these crops or use in the year before planting these crops.

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## ● Plan to provide written comments

Overview of stewardship programs

● Mark White, Executive Director, Environmental Resources Coalition ● Todd Barlow, Syngenta State Government Relations Manager

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## Proposed topics for future discussion and data submissions
● Toxicology and Drinking Water Monitoring

- Selection of BMD

- A trazine Monitoring Program (AMP) ● Ecotoxicology and AEMP

- Aquatic Level of Concern

- Atrazine Ecological Monitoring Program

- Sub-lethal Effects (amphibians, fish, reptiles)

7 - Endangered Species Assessment


# Toxicology and potential BMD selection
● Pulsatile LH Study with NOEL of 6. 25 mg/kg/day is More Relevant for Calculation of the Point of Departure (POD)

- NOEL for a functional indicator of effect on pulsatile LH release is for a functional indicator of effect on pulsatile LH release is 6.25 mg/kg/day – pubertal assay.

- NOEL for distributed dosing on the LH surge is greater than 50 mg/kg/day.

- LE rat has a highly variable (or unstable) estrous cycle, more comprehensive data exist for SD and Wistar rats.

- Bolus dose is not reflective of human exposure.

8 - Distributed dose has no effect at ≥ maximum tolerated dose on LH surge or reproductive endpoints.

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5 Toxicology - Studies In-progress
● Updated version of the PBPK model ● Non-human primate pharmacokinetic study ● Identification of metabolit es in the non-human primate ● Validation of PBPK model ● Metabolism of Atrazine in H295R ● Atrazine metabolism in liver – Changes in Hepatic Phase I and Phase II Biotransformation Enzyme Expr ession and Substrate Availability Following Atrazine Exposure ● Additional university research on mode of action

9 Additional university research on mode of action



### Atrazine Monitoring Program and Characterization of Exposure ● Atrazine exposure is fully characte rized. Using the existing 7-day monitoring data along with a conservati ve bias factor shows that MOEs for short term exposure are acceptable. ● Currently 38 Community Water Systems Currently 38 Community Water Systems

- 4 eligible for waiving ● Daily monitoring program

- Flowing water bodies – Two years of monitoring complete

- Static water bodies – second year finishing up ● Rural well overview report to be submitted

- Miller et al 2014 Rural well water quality and potential vulnerability

10 Miller et al . 2014 . Rural well water quality and potential vulnerability in the Midwest. Groundwater Monitoring & Remediation. XX:000-000 (plan submit to journal in 2013).

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6 Ecotoxicology – Aquatic Level of Concern ● Lines of Evidence Supporting a Level of Concern of 25-30 μg/L for 60-days

- SAP recommended calibration to the micro-/mesocosm dataset according to Giddings (2012) and recommended that all studies conducted at concentrations ≤ 30 μ g/L be rescored and/or dropped conducted at concentrations be rescored and/or dropped from the dataset

- The resultant 60-d LOC ranges from 25-30 μg/L

- Based on the specific-growth-rate (SGR) transformed aquatic plant data from single species laboratory studies EC50’s range from 24 to 706 μg/L

- Based on 5 non-linear regression models, the HC5 from the SGRb d SSD f 36 61 t 69 46 /L

11 b ase d SSD range f rom 36 . 61 t o 69 . 46 μg /L ● Periphyton, phytoplankton, and ma crophytes recover rapidly from atrazine exposure individually and at the community level

● Biomonitoring of algal community dynami cs in 6 Midwestern streams over the course of the corn growing season (April – July) ● Community sensitivity and recovery eval uation of native periphyton communities collected from 6 Midwestern stream s over the course of the corn g rowin g season 

### Ecotoxicology – Ongoing Studies
g g (April – July) ● Biosurvey assessment of benthic communities, and physical habitat in 6 Midwestern streams during the summer window of the corn growing season ● Evaluation of algal sensitiv ity following pulsed exposure ● Additional ecotox modelling ● Additional university studies (amphibian al gal symbiosis, design/planning for lotic mesocosm)

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7 Sub-lethal Effects (amphibians, fish, reptiles) ● The Weight of Evidence manuscript on fish, amphibians and reptiles to be submitted to the EPA during the 60-day comment period.

- App roach p resented to 2012 SAP Sex Ratio pp p

- More than 200 atrazine publications

- Each study is scored for strength of methods, relevance of the biological response to survival, growth and reproduction.

- 36 scored biological responses in 29 fish 24 amphibians & 7 reptile species

13 fish , 24 amphibians & 7 reptile species . ● Immune toxicity study - The Univer sity of Guelph finalizing study examining cortisol responses in z ebrafish after atrazine, DACT, DEA, DIA exposure and a stress challenge (forced swimming speed).



### Ecotoxicology – Atrazine Ecological Monitoring Program ● Monitoring continues at 9 sites ● Data Extrapolation to non-monitored watersheds o Validated models based on current atrazine monitoring data to be used for water exposure assessment (ie. PRZM-Hybrid, WARP, PCA, etc.) ● Reports in progress

- Principle component analysis

- Assessments based on watershed characteristics Oth it i / d li t

14 - Oth er mon it or i ng / mo d e li ng assessmen t s

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8 Partial listing of studies being published in the peer reviewed literature

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● Foradori, C. D., A. D. Zimmerman, et al. (2013). "Atrazine inhibits pulsatile gonadotropin-releasing hor mone (GnRH) release without altering GnRH messenger RNA or protein levels in the female rat." Biol Reprod 88 (1): 9/1-9/7. 

### Toxicology - Recent Publications

● Foradori, C. D., L. R. Hinds, et al . (2011). "The differential effect of atrazine on luteinizing hormone release in adrenalectomized adult female wistar rats." Biol Reprod 85 (4): 684-689.

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9 Toxicology - Publications in progress ● Reproductive effects of atrazine – Repoduc tive Toxicity Studies with Atrazine and its Major metabolites in Rats ● Developmental effects of atrazine – D evelopmental Toxicity Studies with Atrazine and its Major Metabolites in Rats and Rabbits ● PBPK model – PBPK Model for Atrazine and its Chlorinated Metabolites Developed for the Rat and Scaled to Human ● Rat pharmacokinetics – Comparison of the Pharmacokinetics of Atrazine and its Chlorinated Metabolites After Gavage or Dietary Administration to the Female Sprague-Dawley Rat ● Risk assessment – PBK-based Probabilistic Risk Assessment of Exposure to Total Chlorotriazines in drinking water ● LE vs SD reproductive function – The E ffects of Atrazine Administered by Gavage or in the Diet on Luteinizing Hormone Surge and Fertility of Sprague Dawley and Long Evans Female Rats

17 and Long Evans Female Rats ● 24-month estrous cycle dat a – Lifetime Study of R eproductive Aging in the Female Sprague-Dawley Rat ● Immunotoxicity Study – Acitv ation of the Hypothalamic-Pit uitary-Adrenal Axis by High Doses of Atrazine Does Not Affect the Integrity of I mmune Responses in Male or Female Sprague-Dawley Rats


### Toxicology - Publications in progress (continued) ● LH surge – Exposure to Atrazine S uppresses the Estrogen- Induced Luteinizing Hormone (LH) Surge in Ovariectomized Sprague-Dawley Female Rats in a Time-Dependent Fashion.

- 1, 2, 3, 4, 8, or 14 days exposure ● Corticosterone following atrazine exposure – Acute Oral Administration of following atrazine exposure Acute Oral Administration of Atrazine Stimulates Corticosterone Rel ease by Acting at the Level of the Pituitary ● Aromatase and Atrazine review paper – Eva luation of the Po tential Mechanisms of Actions Underlying the Effect of Tr iazines on Aromatase Expression InVitro: Relevance to Man and the Environment

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10 Published Literature ● Andrus, JM, Brain, RA, Bollman W, Su llivan S, Winter D, Scanlan M, Waggoner JB , and Hosmer AJ. 2013. Biomonitoring of Select Sites in the Midwestern United States Coinciding with Va rying Levels of Atrazine and Other Physicochemical Attributes. Environmental Toxicology and Chemistry I n Prep ● Prosser RS, Brain RA, Andrus JM, Hosmer AJ, Solomon KR, and Hanson ML. 2013. Assessing temporal and spatial variat ion in sensitivity of field-derived periphyton communities to, and ability to recover from, atrazine exposure. Environmental Toxicology and Chemistry In Prep ● Lenwood W. Hall, LW, Killen WD, Anders on RD, Hosmer AJ, Brain RA. 2013. Assessment of Periphyton, Aquatic Macrophytes, Benthic Communities, and Physical Habitat in Midwestern United States Streams Coinciding with Varying Historical Concentrations of Atrazine. Environmental Monitoring and Assessment In Prep

19 ● Prosser RS, Baxter LR, Brain RA, Solomon KR, and Hanson ML. Assessing the sensitivity and potential for recovery of phytoplankton and periphyton exposed to contaminants using pulse am plitude modulated fluorometry. Journal of Visualized Experiments (JoVE) Submitted 06/2013



### Published Literature Cont. ● Prosser RS, Brain RA, Hosmer AJ, Solomon KR, and Hanson ML. 2013. Assessing the PSII sensitivity and reco very of field-collected periphyton communities under laboratory conditions. Ecotoxicology Submitted 01/2013. ● Baxter LR, Brain RA; Prosser RS, Solomon KR, and Hanson ML. 2013. Sensitivity of an alga to atrazine is not enhanced by pr evious acute exposure. Environmental Pollution Accepted 06/2013. ● Bartell SM, Brain RA, Hendley P; and Nair SK. 2013. Mode ling the Potential Effects of Atrazine on Aquatic Plant Co mmunities in Midwestern Streams. Environmental Toxicology and Chemistry Accepted 06/2013 ● Andrus JM, Winter D, Scanlan M, Su llivan S, Bollman W, Waggoner JB, Hosmer AJ, and Brain RA. 2013. Seasonal synchroni city of algal assemblages in three Midwestern streams exhibiting varying levels of atrazine and other chemicals from a g ricultural field in p uts. Science of the Total Environmen t 458-460:125 –

20 g p 139. ● Brain, RA, Arnie, JR, Porch, JR, and Hosmer, AJ. 2012. Recovery of Photosynthesis and Growth Rate in Green, Blue-Green, and Diatom Algae After Exposure to Atrazine. Environmental Toxicology and Chemistry 31(11):2572– 2581.

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11 Published Literature Cont. ● Brain RA, Hosmer AJ, Desjardins D, Kendall TZ, Krueger HO, and Wall SB. 2012. Recovery of duckweed from ti me-varying exposure to atrazine. Environmental Toxicology and Chemistry 31(5):1121–1128. ● Brain RA, Hoberg J, Hosmer AJ, and Wall SB. 2012. Influence of light intensity on the toxicity of atrazine to t he submerged freshwater macrophyte Elodea Canadensis. Ecotoxicology and Environmental Safety 79:55–61.

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### Published Literature
● Van Der Kraak GJ, Hosmer AJ, Hanson ML, Kloas W and Solomon KR. Effects of atrazine in fish, amphibians, and r eptiles: An analysis based on quantitative weight of evidence. Critical Reviews in Toxicology. in prep ● Matsumoto J Hosmer AJ and Van Der Kraak GJ The effects of atrazine on the Matsumoto J , Hosmer AJ and Van Der Kraak GJ . The effects of atrazine on the cortisol stress respons e in the zebrafish ( Danio rerio ) Comparative Biochemistry and Physiology C Comparative Pharmacology . in prep

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12 Atrazine Ecological Monitoring – Publications in Progress
● Miller et al., 2014. Development of an agronomic approach to define watershed scale chemical applications for environment al fate modeling. J. Environ. Qual. XX:000-000. (submit to J. in 2013). ● Miller et al 2014 A combined PRZM and monitoring approach for agricultural Miller et al ., 2014 . A combined PRZM and monitoring approach for agricultural assessment modeling: PRZM-Hybrid. ES&T . XX:000-000. (submit to J. in 2013). ● Chen, W. and P. Mosquin. 2014. Impact of alternative monitoring frequencies on estimation of atrazine rolling average envir onmental concentrations. J. Environ. Qual. XX:000-000 (submit to J. in 2013). ● Mosquin, P. and W. Chen. 2014. Bias factors of different sampling frequency and its relationship with watershed char acteristics. (submit to J. in 2014). ● Chen, W. and B. Munoz. 2014. Temporal trend of atrazine occurrence in raw t f U S it t t (1994 2012) ES&T ( b it t J i

23 wa t ers o f U . S . commun it y wa t er sys t ems (1994 - 2012) . ES&T . ( su b m it t o J . i n 2014). ● Mosquin et al., 2014. Predicted daily concent rations with covariate time-series combining watershed model and monito ring data. (submit to J. in 2014).



### Recent publications ● Mosquin et al., 2012. Estimation of upper centile concentrations using historical atrazine monitoring data fr om community water systems. J. Environ. Qual. 41:834-844. Ch W 2005 Si l th d f ti ti t ti ● Ch en, W . 2005 . Si mp l e me th o d s o f es ti ma ti ng exposure concen t ra ti ons of pesticide resulting from non-point applications in agricultural drainage networks. In Techniques in Aquatic Toxicology , Ostrander, G.K. ed. CRC Press: New York, vol. 2, pp. 357. ● Chen et al., 2002. A pesticide surface water mobility index and its relationship with concentrations in agricultural drainage watersheds. Environ. Toxicol. Chem. 21:298-308.

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