UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C. , 20460 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

PC Code: 044309 

DP Barcode: 427484 

MEMORANDUM 

DATE: 

SUBJECT: 

TO: 

FROM: 

Through: 

February 16, 20 16 

EFED Response to Public Comments Submitted on the Federal Register Notice of 

Receipt for the Clothianidin Experimental Use Permit (59639-EUP-Rl) 

Marianne Lewis. Risk Manager Reviewer 

Venus Eagle, Product Manager Team I 

Invertebrate - Vertebrate Branch 3 

Registration Division (7505P) 

lvl/// _.,.,, 1...---- d/!tr"/11: Michael Wauman. Biologist / '{, ./!. /'?f'· · \ 

William P. Eckel. Ph.D. Senior Science Advisor A_/ /J / f t~ z./•G 1 C 

Environmental Risk Branch 6 _.. (/V v(/f/4vv 

Environmental Fate and Effects Division (7507P) rJ 

Mark Corbin. Branch Chief ~ 2.--l-1> -\ .(, 

Monica Wait. Risk Assessment Process Lea.der I 0 r-__ _ nl\ ~..L) 2 -l-lr l<b 

Environmental Risk Branch 6 1/ A !J 4_)'- L)C>Y ,., •\ 

Environmental Fate and Effects Division (7507P) -~ 

The notice of receipt of an application for a clothianidin experimental use permit (59639-EUPRI) was open for a 30-day public comment period in the docket EPA-I-IQ-OPP-20 14-0667 at 

regulations.gov. The purpose of this document is to address public comments and respond to 

technical/science-related questions submitted by the Pollinator Stewardship Council. 

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Comments submitted by the Pollinator Stewardship Council (PCS)- EPA-HQOPP-2014-0667-0015 

PSC Comment: PSC commented that Clothian idin is documented as causing both acute and 

chronic hann to honey bees when used on corn. To support this point, they cite Tapparo et al., 

2012 indicating that exposure levels from use on corn can be very high and can result in colony 

losses as well as Di Prisco et al., 2013 which they state indicates that clothianidin adversely 

affects the insect immune response and promotes replication ofviral pathogens. 

EPA Response: EPA has previously reviewed the Tapparo eta/., 20 12 paper (ECOTOX 

reference number E 159259) and considered the study to be of qualitative use in risk assessment, 

providing information on potential fugitive dust emitted during the sowing of treated seed and 

the potential effects of equipment modifications on those residue levels. This study used 

clothianidin-treated seed at 1.25 mg a.i./seed and measured clothianidin residues at the air fan 

outlet ofthe drilling machine, at 5-10 meters from the seeding machine and in free foraging bees 

flying through the sown field and caged bees at 1-9 meters from the sowing equipment. 

Reported clothianidin residues in the free foraging (78- 1240 ng/bee) and caged bees (25-1394 

ng/bee) however were considerable. However, in this study all honey bee exposure would have 

been to residues in abraded dust from the seed treatment. 

According to the proposed EUP label, the maximum rate of active ingredient per seed is 0.5 mg 

a.i./seed, which indicates that exposure to clothianidin residues from abraded dust is likely to be 

lower than that under the current labeled maximum rate of 1.25 mg a. i./seed. The remainder of 

the clothianidin application would be an in-furrow soil application that is unlikely to result in 

significant spray drift as in-furrow treatments are conducted at low boom heights. EPA therefore 

considers that acute exposures to honey bees foraging in or near the field at the time of 

application are likely to be similar or lower than those from the currently registered use on corn. 

However, it is difficult to determine from the currently available data whether chronic residues in 

corn pollen following systemic uptake may be higher under the proposed EUP label than under 

the currently registered seed treatment. Using the limited corn pollen residue dataset (MRID 

49372102, Appendix 26, data currently in review) that the registrant submitted to support the 

EUP, residues from in-furrow applications (either on clothianidin treated-seed at 0.25 mg 

a. i./seed or untreated seed) were generally reported to be similar to the available data for corn 

pollen following seed treatment at 1.25 mg a. i./seed (MRID 4829880 I, mean residues of3.4 

ng/g, with an upper 90% bound of 5.2 ng/g) though two samples in the new (in-furrow treatment 

only) data contained substantially higher (25-28 ng/g) residues, which was likely at least partially 

due to contamination at that site (control plants at that site contained pollen with clothianidin 

residues of 12.4 ng/g). 

The available data indicates that clothian idin residues in pollen from corn plants following 

systemic uptake may be similar under the proposed EUP as they are under the currently 

registered seed treatment application, but more data would be needed to conclusively determine 

th is. Without additional data measuring residues in corn pollen from the in-furrow use pattern, 

any ecological risk assessment conducted to evaluate the risk posed by this use pattern to honey 

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bees and other beneficial terrestrial insects will use conservative measures to evaluate the 

potential residues in corn pollen. 

The Di Prisco eta/., (20 13) article cited by PSC does not provide any information d irectly 

related to EPA's apical endpoints of survival, growth or reproduction. However, the study 

authors' reported effects of adverse effects on terrestrial insects (honey bees and flies) 

immunosuppression capabilities and consequential promotion of deformed wing virus replication 

in honey bees may be considered in future risk assessments, along with other reported sublethal 

effects in registrant subm itted and open I iterature data. 

PSC Comment: PSC reiterated that the registrant requested an EUP not an emergency use 

which would have been considered as per the April2, 2015 letter. PSC supports the EPA's 

decision for not allowing any new uses until the pollinator data has been received and assessed. 

They are particularly concerned that clothianidin is soluble in water and has the potential to 

contaminate surface waters which honeybees rely upon for drinking. 

PSC cites a study "Widespread Use and Frequent Detection ofNeonicotinoid Insecticides in 

Wetlands of Canada's Prairie Pothole Region (20 14)" which states that researchers found: 

" ... neonicotinoid use in increasing and becoming more widespread with concerns for 

environmental loading, while frequently detected neonicotinoid concentrations in Prairie 

wetlands suggest high persistence and transport into wetlands." 

In another paper cited by PSC: " ... In fact, our data shows that honey bees and native pollinators 

are facing unprecedented cumulative exposure to these insecticides from combined residues in 

pollen, nectar and water." 

PSC is opposed to the proposed soil drenching of clothianidin- they feel that this would increase 

the soil profile compared to a seed treatment. "Soil drench application enables the crop root 

system to take up more of the systemic pesticide treatment application. This ensures that plant 

will retain a higher level of pesticide for a longer period of time. This is because the roots 

remain in the larger treated soil profile longer as the plant grows. The high solubility property of 

clothianidin would make the treated soil profile even larger." 

PSC states: " ... we support EPA 's decision not to approve new outdoor uses, and strongly 

encourage EPA to stand by their decision by denying the current application for an EUP." 

EPA Response: Several papers have recently been published in the open sc ientific literature 

(see below), in which concentrations of clothian idin have been measured in various types of 

water bodies, including streams with drainage areas of 521 to 836,000 km2 (Hladik et al, 20 14), 

prairie potholes (Main et al., 20 14), and puddles on clothianidin-treated fields (Samson-Robert et 

al., 20 14). Exposures in the streams and prairie potholes are in line with EPA modeling 

estimates using the standard farm pond, but those measured in the on-field puddles are higher. 

Collectively, these studies document that clothianidin use has the potential to reach water that 

might be used by honeybees or other wildlife for a drinking water source. EPA has not currently 

determined what dose of clothianidin consumed via drinking water might be harmful to 

honeybees, but generally believes that the most relevant route of exposure of clothianidin to bees 

Page 3 of 4 
will be dietary through consumption of contaminated pollen and nectar or dermal through 

contact with abraded seed dust conta ining clothianidin residues, spray drift or contact with 

residues on plant surfaces (US EPA, 20 12). However, EPA is currently working to develop a 

framework to assess risk to pollinators from the consumption of residues in drinking water. 

References: 

• Hladik, M.L., D.W. Kolpin, and K.M. Kuivila, 20 14. Widespread occurrence of 

neonicotinoid insecticides in streams in a high corn and soybean producing region, USA. 

Environmental Pollution, 193 (20 14) 189-1 96. 

• Main A.R., J.V. Headley, K.M. Peru, N.L. Michel, and A.J. Cessna. 2014. Widespread 

Use and Frequent Detection ofNeonicotino id Insecticides in Wetlands of Canada's 

Prairie Pothole Region. PLoS ONE 9(3), March 2014. 

• Samson-Robert, 0 ., G. Labrie, M. Chagnon, and V. Fournier, 20 14. NeonicotinoidContaminated Puddles of Water Represent a Risk of Intoxication for Honey Bees. PLoS 

ONE, December 1, 2014. 

• Di Prisco, G., V. Cavaliere, D. Annoscia, P. Varricchio, E. Caprio, F. Nazzi, G. Gargiulo 

and F. Pennachio, 2013. Neonicotinoid clothianidin adversely affects insect immunity 

and promotes replication of a viral pathogen in honey bees, PNAS, 110(46), November, 

2013. 

• Tapparo, A., D. Marton, C.Giorio, A. Zanella, L. Solda, M. Marzaro, L. Vivan, V. 

Giro1ami, 20 12. Assessment of the environmental exposure of honeybees to particulate 

matter containing neonicotinoid insecticides coming from corn coated seeds. Environ. 

Sci. Techno., 46(5): 2592-2599. March, 6, 2012. 

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