# APPENDIX H.

This appendix provides more detail on several studies submitted by Syngenta after EPA’s submission

cutoff date of November 2014. While the vast majority of registrant

- submitted studies are discussed or

considered in the body of the risk assessment , for clarity and transparency, a few studies were selected for inclusion in this appendix , as they were not specifically incorporated into the risk assessment . None of the information provided below in this appendix changes the risk conclusions presented in the

assessment.

Terrestrial Plants

In late 2015 Syngenta submitted two new terrestrial plant toxicity studies. These studies followed the

s eedling e mergence (850.4100) and v egetative v igor (850.4150) g uidelines

, however

, also included

concur rent continuation studies for both studies to explore the potential recovery from atrazine caused inhibition of biomass and height endpoints across the tested species. A comparison to the endpoints

used in the risk assessment and a brief discussion of the continuation studies are d iscussed below.

Seedling Emergence

The Martin 2015 seedling emergence study resulted in less sensitive endpoints than those for the same
taxa tested in Chetram 1980. Several of the species indicated that little to no effect had b een observed

based on the 14

- day results. W hen the study was continued out to 28

- d ays, significant effects on dry

weight were observed for several species. For cabbage and onion the results were similar (within an order of magnitude) to the endpoints repor ted in the Chetram (1980) study , while other taxa were less sensitive by approximately 10

- 20x . The results of this study indicate that atrazine effects on terrestrial pla nt growth and biomass may continue and have long term impacts after an exposure at or near seed
germination

.
Table 1. Comparison of the toxicity of atrazine when exposed to terrestrial plants at the seedling emergence phase of plant develop ment. (Bolded IC 25 

### values indicate the most sensitive endpoint for each taxon).

Study Chetram 1980 Ma rtin 2015
Final 14

- day Study Martin 2015
Final 28

- day Study

Species Endpoi

nt NOEC EC 25 /IC

25 Endpoi

nt NOE

C EC 05 /IC

05 EC 25 /IC

25 Endpoi

nt NOEC EC 05 /IC

05 EC 25 /IC

25

Cabbage Dry

weight 0.01 0.014 Dry weight 0.09

7 0.0035

1 0.0299 Dry

weight 0.009

9 0.0014

3 0.0177

Carrot Dry

weight 0.002

5 0.003 None 0.04

9 >0.049 >0.049 None 0.049 >0.049 >0.049

Cucumb

er Dry

weight 0.005 0.013 None 0.1 >0.10 >0.10 Height 0.004

7 0.0037

6 >0.10

Lettuce Dry

weight 0.002

5 0.0025 None 0.04

9 >0.049 >0.049 Dry weight 0.049 0.0222 0.0475

Oat Dry

weight 0.002

5 0.004 Dry

weight 0.02

1 0.0403 0.0456 None 0.047 >0.047 >0.047Study Chetram 1980 Ma rtin 2015

Final 14

- day Study Martin 2015

Final 28

- day Study

Onion Dry

weight 0.005 0.009 None 0.1 >0.10 >0.10 Dry weight 0.025 0.0043

2 0.0341

Ryegrass Dry

weight 0.005 0.007 None 0.1 >0.10 >0.10 Dry weight 0.1 0.0285 >0.10

Soybean Dry

weight 0.025 0.19 Dry weight 0.44 0.316 >0.44 Dry weight 0.44 0.0493 >0.44

Tomato Dry

weight 0.01 0.034 Dry weight 0.04

7 0.0168 0.0527 Dry weight 0.095 0.0776 0.146



### Vegetative vigor

The Martin 2015 study provides several lower IC25 endpoints for the 21

- day study as compared to the Chetram 1980 study ( Table 2 )

. The continuation study showed that after 42

- days some species may have recovered to control biomass and growth levels. However

, several species had continued impact on dry

- weight and h eight endpoints, and several showed plant survival as the most sensitive endpoint. In the case of oat and soybean

, endpoints after 42

- days of post treatment recovery were more sensitive

than those at 21

- days.

The addition of these new data into the specie s sensitivity distribution (SSD) for vegetative vigor endpoints only slightly affected the resulting distribution . As Figure 1 illustrates, the SSDs with and

without the additional 21

- day data are nearly the same . There were relatively minor changes in t he

concentrations at the low end of the distribution, and slightly greater changes for higher HCp estimations ( Table 3 )

. While these are more sensitive endpoints, the conclusions presented in the risk assessment would not change with their addition given that risk to terrestrial plants and communities was identified off the field for large proportions of the 2015 SSD.

Table 2. Comparison of the toxicity of atrazine when exposed to terrestrial plants at the seedling emergence phase of plant development. (Bo lded IC 25 

### values indicate the most sensitive endpoint for each taxon).

Study Chetram 1980 Martin 2015

Final 21

- day Study Martin 2015

Final 42

- day Study

Species Endpoi

nt NOE

C EC 25 /IC

25 Endpoi

nt NOEC EC 05 /IC

05 EC 25 /IC

25 Endpoi

nt NOEC EC 05 /IC 0

5 EC 25 /IC

25

Cabbage Dry

weight 0.00

5 0.014 Dry

weight 0.044 0.0148 0.059 None 0.22 >0.22 >0.22

Carrot Dry

weight 2 1.7 Dry weight <0.009

5 0.0123 0.0544 Survival 0.22 0.22 0.31

Cucumb

er Dry

weight 0.00

5 0.008 Dry

weight <0.009

9 0.0013

2 0.0145 Survival 0.047 0.0828 0.134

Lettuce Dry

weight 0.25 0.33 Dry weight 0.0044 0.0065

3 0.0215 Dry

weight 0.0095 0.00844 0.061

Oat Dry

weight 2 2.4 Dry weight 0.45 0.211 0.354 Survival 0.047 0.0919 0.204Study Chetram 1980 Martin 2015
Final 21

- day Study Martin 2015
Final 42

- day Study

Onion Dry

weight 0.5 0.61 Dry weight <0.044 0.0067

3 0.0379 Dry

weight 0.092 0.0145 0.0996

Ryegrass Dry

weight 4 >4 Dry weight 0.22 0.0292 0.243 Survival 0.97 0.983 2.08

Soybean Dry

weight 0.02 0.026 Dry weight 0.0074 0.0042

2 0.018 Dry

weight <0.004

4 0.00041

9 0.0039

7

Tomato Dry

weight 0.5 0.72 Dry weight 0.0074 0.0057

2 0.0286 Dry

weight 0.094 0.0411 0.119



### Figure 1. Species Sensitivity Distributions calculated with (2016 VV SSD) and without (2015 VV SSD) the addition of the Martin (2015) 21

- day toxicity data reported in Table 2.

### Table 3. Specific HCp values estimated with the vegetative vigor SSDs presented in Figure 1.

HCp 2015 VV SSD

(lbs a.i./A) 2016 VV SSD

(lbs a.i./A)

5 0.016 0.019

25 0.057 0.063

50 0.149 0.126

75 0.383 0.253

95 1.361 0.819

Algal Symbionts of Salamanders

Syngenta submitted a few new studies describing the isolation, culturing and testing for atrazine toxicity on the algae Oophila sp., an algae that forms a symbiotic relationship with some salamander species
(MRIDs 

### 49639109, 49639110, 49535803, 49535801 )



### . These studies

, while relevant to the potential

effects due to atrazine environmental exposure s , and prior study identification as a potential risk concern ( Oliver et al. 2010 ), do not test the effect of atrazine on the salamander eggs or algal symbiont

whi le in the symbiotic relationship. The direct effects on the algae do not differ greatly from those seen with other free living algal species and thus do not contribute new data for refinement of the current

risk assessment.

Water Monitoring Data Analysis and Accounting for Uncertainty

Two studies were submitted by Syngenta in late 2015 that evaluated bias factors (Chen and Mosquin 2015) and different kriging methods for predicting concentrations of atrazine in surface water (Chen et

al. 2015). Th ese two studies are summarized here and are in general agreement with the atrazine risk

assessment.

Chen and Mosquin (2015) derived additional bias factors estimates from the Atrazine Monitoring Program (AMP) and the Atrazine Ecological Effects Monitoring Program (AEEMP) from 2011, 2012, and 2013. Bias factors were estimated using systematic sampling intervals of 4, 7, 14, and 28 days for estimation of annual maximum, 4 day average, 7 day average, 14 day average, 30 day average, and 60 day rolling average atrazine concentrations. The monitoring data, expressed on a site

- year basis, were aggregated according to hydrology (static vs

. flowing), watershed size, and sampling time for estimation group means and 95 th 

### centile multiplicative factors. The bias fact or is equal to the 95 th 

### centile multiplicative factors. It is calculated by the true value divided by the 5 th 

### percentile subsample value. The estimated BF factors for yearly maximum daily atrazine concentration range from 1.14 to 2.75 for a 4 day samplin g interval, 1.40 to 6.62 for 7 day sampling interval, 1.70 to 15.57 for 14 day sampling interval, and 2.36 to 38.28 for the 28 day sampling interval. The estimated BF factors for 60 day average atrazine concentration range from 1.05 to 1.44 for a 4 day sa mpling interval, 1.06 to 1.84 for 7 day sampling interval, 1.13 to 3.13 for 14 day sampling interval, and 1.51 to 5.54 for the 28 day sampling interval. From this analysis, the data illustrate that atrazine BFs are higher for flowing water bodies

### compared to static water bodies. Also, the highest BF are associated with small Midwestern streams

with highly variable flow conditions ( i.e. , AMP).

Chen et al . 2015 explored various data interpolation methods including ordinary kriging, universal kriging with use of PRZM time series predictions as a covariate, and linear interpolation using log

- scale

data were evaluated for 42 site

- years of atrazine monitoring data from the Atrazine Ecological Effects Monitoring Program (AEEMP). These data have daily monitorin g during the atrazine runoff period. The interpolation methods were evaluated on the monitoring data using a 7 and 14 day systematic sampling interval for estimation of 1day (maximum yearly), 7 day,14 day, and 30 day rolling average of atrazine

concentrat ions. Root mean square errors were calculated by comparing interpolated estimated atrazine

concentrations to ac tual atrazine concentrations. Estimation of the 1 day (maximum yearly) was no different among the various interpolation methods. Longer durati on exposure concentrations (ie, 7, 14, and 30 day rolling average concentrations) were better estimated using ordinary kriging. Linear prediction of log transformed data can provide a reliable interpolation method for right skewed data. Kriging predictions intervals was comparable atrazine concentrations for non

- sampled days.

Surface Water Monitoring Data

Syngenta submitted 2015 AEEMP and AMP mo nitoring program data results in early 2016. The results indicate exceedances of ecological thresholds

. Tabl e 4 below includes the 2015 peak and 60

- day average concentrations for the sites that were monitored in 2015, and also includes the historical data

for these sites

, which were included in the risk assessment. These data illustrate that concentrations will vary year to year within a site, however they also indicate that exceedances of the aquatic plant community CELOC are common within and across these sites, and that peak concentrations continue to exceed many of the aquatic animal endpoints. Table 5 provides the summary statistics for the 2015 AMP monitoring program results, which also showed multiple exceedances of the ecological thresholds.

### Table 4. AEEMP m onit oring p rogram d ata for sites submitted for the 2015 growing season. Peak and

60

- day maximum average concentrations are provided for each year the site was monitored. Bold values indicate exceedance of the CELOC (3.4 ug/L).

State Site Year Peak (ug/L) Max imum 60

- day average (ug/L)

IA IA

- 04 2010 73.4 10.4

IA IA

- 04 2011 36.0 4.3

IA IA

- 04 2012 78.4 10.9

IA IA

- 04 2013 46.1 8.9

IA IA

- 04 2014 142.4 26.1

IA IA

- 04 2015 31.5 5.2

IA IA

- 05 2010 74.2 11.9

IA IA

- 05 2011 169.0 12.8

IA IA

- 05 2012 33.5 7.0

IA IA

- 05 2013 56.5 6.9

IA IA

- 05 2014 344.3 96.6

IA IA

- 05 2015 34.7 6.3

LA LA

- 04 2010 32.9 6.3

LA LA

- 04 2011 167.4 27.4

LA LA

- 04 2012 59.0 11.5

LA LA

- 04 2013 193.7 24.2

LA LA

- 04 2014 76.8 9.7

LA LA

- 04 2015 140.8 26.5

MO MO

- 01 2004 65.9 19.4

MO MO

- 01 2005 182.8 26.1

MO MO

- 01 2006 82.8 17.8

MO MO

- 01 2007 91.6 10.7

MO MO

- 01 2008 78.2 7.3

MO MO

- 01 2009 73.0 11.5

MO MO

- 01 2010 25.2 5.1

MO MO

- 01 2011 18.8 4.5

MO MO

- 01 2012 13.6 1.4

MO MO

- 01 2013 19.2 2.4

MO MO

- 01 2014 16.9 3.0

MO MO

- 01 2015 90.6 14.4

MO MO

- 02 2004 53.8 16.8

MO MO

- 02 2005 28.1 11.5

MO MO

- 02 2006 43.2 15.4

MO MO

- 02 2007 16.2 3.5

MO MO

- 02 2008 56.6 12.6

MO MO

- 02 2009 155.2 14.6

MO MO

- 02 2010 31.0 8.4

MO MO

- 02 2011 40.7 6.6State Site Year Peak (ug/L) Max imum 60

- day average (ug/L)

MO MO

- 02 2012 8.7 1.9

MO MO

- 02 2013 64.1 3.0

MO MO

- 02 2014 39.6 6.9

MO MO

- 02 2015 19.1 6.1

MO MO

- 07N 2010 92.5 19.8

MO MO

- 07N 2011 90.9 14.6

MO MO

- 07N 2012 41.1 12.4

MO MO

- 07N 2013 42.4 10.1

MO MO

- 07N 2014 285.9 69.0

MO MO

- 07N 2015 43.4 9.0

MO MO

- 08 2010 69.7 14.5

MO MO

- 08 2011 68.2 14.1

MO MO

- 08 2012 66.3 13.2

MO MO

- 08 2013 41.2 6.0

MO MO

- 08 2014 64.8 17.4

MO MO

- 08 2015 34.7 9.9

NE NE

- 04 2005 49.9 49.4

NE NE

- 04 2006 125.0 102.3

NE NE

- 04 2007

- -

NE NE

- 04 2008 147.7 21.2

NE NE

- 04 2009 38.2 38.2

NE NE

- 04 2010 189.3 49.6

NE NE

- 04 2011 13.0 3.9

NE NE

- 04 2012 8.4 2.4

NE NE

- 04 2013 6.9 2.9

NE NE

- 04 2014 4.2 0.9

NE NE

- 04 2015 6.3 1.5

TX TX

- 01 2010 105.2 19.5

TX TX

- 01 2011 6.4 3.0

TX TX

- 01 2012 133.9 15.6

TX TX

- 01 2013 56.0 20.7

TX TX

- 01 2014 39.3 8.0

TX TX

- 01 2015 98.4 33.1

### Table 5. AMP s urface w ater m onitoring p rogram d ata for sites submitted for the 2015 growing season. Bold values indicate exceedance of

the CELOC (3.4 ug/L).

State Site ID Site Code Number
of

Detections Number

of Non

Detections Peak

concentration (ug/L) Maximum 21

-

day average

concentration (ug/L) Maximum 60

-

day average

concentration (ug/L)

Illinois IL1570250 Evansville 35 0 12.8 6.7 6.1

Illinois IL1910100 Fairfield 26 0 22.0 16.6 9.9

Illinois IL0290250 Mattoon 36 7 1.6 1.5 1.1

Illinois IL1170700 Mt. Olive Water Works (Old Lake and Finished) 35 0 2.2 2.2 2.1

Kansas KS2012301 Beloit Water
Department 35 0 20.8 14.4 7.3

Kansas KS2012513 Coffeyville 35 6 7.0 5.3 3.0

Kansas KS2012520 Elk City 35 20 7.5 4.0 2.5

Kansas KS2009911 Great Plains Development Authority 35 1 9.4 7.6 5.4

Kansas KS2004102 Herington 35 0 0.8 0.7 0.7

Kansas KS2004901 Howard, City of 24 0 0.2 0.2 0.2

Kansas KS2000111 Humboldt 35 0 26.7 10.8 6.3

Kansas KS2012508 Independence, City of 35 6 8.0 4.4 2.4

Kansas KS2000103 Iola 35 1 30.0 17.7 9.1

Kansas KS070000002 Kickapoo Tribal

Waterworks 28 0 12.8 9.7 5.9

Kansas KS2010703 La Cygne (Marais des Cygnes River and Finished) 34 0 2.6 2.5 2.0

Kansas KS2012109 Marais Des Cygnes Public Utility Authority 35 0 3.8 3.0 2.3

Kansas KS2020502 Neodesha 30 15 17.8 8.0 3.4

Kansas KS2009908 Oswego 35 0 5.5 5.1 4.2

Kansas KS2005906 Ottawa, City of 34 0 1.0 0.8 0.8State Site ID Site Code Number

of

Detections Number

of Non

Detections Peak

concentration (ug/L) Maximum 21

-

day average

concentration (ug/L) Maximum 60

-

day average

concentration (ug/L)

Kansas KS2009914 Parsons, City of 35 3 0.8 0.5 0.3

Kansas KS2000119 Public Wholesale WSD

#5 31 0 10.2 8.9 5.1

Kansas KS2016703 Russell Water
Department 35 7 10.0 7.3 3.7

Kentucky KY0890071 Central City Water &

Sewer 34 10 1.8 1.3 0.9

Kentucky KY0920181 Hartford Municipal

Water Works 36 7 3.8 2.9 2.3

Kentucky KY0160294 Morgantown Water System 34 7 5.3 2.5 1.3

Missouri MO1010425 King City 36 0 0.8 0.7 0.7

Ohio OH1400111 Blanchester 35 10 60.1 41.3 24.5

Ohio OH7200311 Fremont City PWS 35 1 1.2 1.2 1.1

Ohio OH3500711 McClure Water

Treatment Plant 35 5 15.2 12.5 7.3

Ohio OH7400614 Ohio American Water

CO

- Tiffin District 34 4 27.0 18.6 9.5

Ohio OH5501211 Piqua (Gravel Pit) 35 8 17.1 12.4 6.8

Tennessee TN0000001 Adams

- Cedar Hill Water System 34 14 6.1 2.7 1.7

Texas TX0290005 GBRA

- Port Lavaca 35 23 0.8 0.4 0.2

Texas TX2040032 Waterwood MUD #1 34 2 0.4 0.3 0.3

### Literature Cited

Baxter, L.; Brain, R.; Rodriguez

- Gil, J.; et al. (2014) Atrazine: Response of the Green Alga Oophilia SP., a Salamander Endosymbiont, to a PSII

- Inhibitor under Laboratory Conditions. Environmental Toxicology and Chemistry 33(8):1858

- 1864. MRID 49535803



### Chen W. and P. Mosquin. 2015. Impact of Alternative Sampling Frequencies on Estimation of

Atrazine Maxim um Rolling Average Concentrations (Addendum to MRID 48936707). Final Report Addendum 3. Performed by RTI International, RTP, NC. Sponsored by Syngenta Crop Protection LLC. (MRID 49639103).

Chen W. P. L. Mosquin, and J. Aldworth. 2015. Kriging Methods for Predicting Atrazine Concentrations in Surface Water Draining Agricultural Watersheds. Performed by RTI International, RTP, NC. Sponsored by Syngenta Crop Protection LLC. (MRID 49639105).

Hanson, M.; Rodriquez

- Gil, J.; Baxter, L.; et al. (2014) Isolation, Identification, and Optimization of Culturing Conditions of the Alga Oophila sp., a Salamander Symbiont, for its Use in Toxicity Testing under Laboratory Conditions: Final Report. Project Number: ATZ2013B, TK0186283. Unpublished study prepared by Universi ty of Guelph. 30p., MRID 49639109

Hanson, M.; Baxter, L.; Rodriquez

- Gil, J.; et al. (2014) Characterization of the Response of the Alga Oophila sp., a Salamander Symbiont, to Atrazine Under Laboratory Conditions: Final Report. Project
Number: ATZ2013A, TK 0186283. Unpublished study prepared by University of Guelph. 52p., MRID

49639110

Martin, J. (2015) Atrazine SC (A8566A)

- Vegetative Vigor Test with Extended Exposure to View Potential Recovery: Final Report. Project Number: 1781/7001, TK0222225. Unpublish ed study prepared by Smithers Viscient Laboratories. 366p. MRID 49639101.



### Martin, J. (2015) Atrazine SC (A8566A)

- Seedling Emergence Test with Extended Exposure to View Potential Recovery: Final Report. Project Number: 1781/7000, TK0222226. Unpublished st udy prepared by Smithers Viscient Laboratories. 341p. MRID 49639102.

Merritt, A. (2015) 2014 Atrazine Monitoring Program Final Report. Project Number: TK001301/03, TK0001612, G/30027. Unpublished study prepared by Syngenta Crop Protection, LLC. 130p. MRID

49560201

Merritt, A. (2015) FIFRA Section 6(a)(2) Annual Report for Atrazine, Simazine and Chlorotriazine Degradates Monitoring Data for Surface Water Samples Collected in the 2014 Atrazine Monitoring Program, 2014 Atrazine Ecological Monitoring Program an d 2014 Simazine Monitoring Program: Final Report. Project Number: T001301/03, TK0001612. Unpublished study prepared by Syngenta Crop
Protection, LLC. 13p. MRID 49579101

Olivier, H.M. and B.R. Moon. 2010. The effects of atrazine on spotted salamander embryo s and their symbiotic alga. Ecotoxicology 19: 654

– 661.

### Rodriguez

- Gil, J.; Baxter, L.; McConkey, B.; et al. (2014) Atrazine: Optimization of Culturing Conditions

for Toxicity Testing with the Alga Oophila sp. (Chlorophyceae), An Amphibian Endosymbiont.

Envi ronmental Toxicology and Chemistry 33(11):2566

- 2575. MRID 49535801