UNITED STATES ENVIRONMENTAL PROTECTION AGENCYWASHINGTON D.C., 20460Office of Chemical Safetyand Pollution PreventionPC Code: 044309DP Number: 383634Date: December 22, 2010MEMORANDUMSUBJECT:Reclassification of MRID 46907801/46907802 Data Package 336888 forClothianidin, PC Code 044309TO:FROM:THRU:Kable Davis, Risk Manager ReviewerVenus Eagle, Risk Manager, RM 01Insecticide BranchRegistration Division (7505P)Anita Pease, Senior BiologistX45-11-111/1°Environmental Risk Branch 6Environmental Fate and Effects Division (7507P)Mark Corbin, Branch ChiefEnvironmental Risk Branch 6Environmental Fate and Effects Division (7507P)12,11-10The purpose of this memorandum is to transmit the Environmental Fate and Effects Division's(EFED's) final Data Evaluation Record (DER) for the study entitled, "An Investigation of thePotential Long-Term Impact of Clothianidin Seed Treated Canola on Honey Bees,Apis melliferaL." (MRID 46907801/46907802) and provide a brief history of activities related to thereclassification of this study.This field study was originally reviewed by EFED in November 2007 and classified as"Acceptable". A subsequent re-review of the study was conducted in November 2010 as part ofa new use assessment for clothianidin seed treatment on mustard seed and cotton. EFEDscientists routinely reevaluate studies to determine whether the information submitted is validand if it is relevant or useful to the regulatory matter in question. In the case of the clothianidinhoneybee field study, the study was reconsidered based on an increased understanding andawareness of the potential uncertainties normally encountered in field studies with honeybees.Based on the initial re-review, which occurred on November 2, 2010, the study was thought to be"Invalid"; however, it was later reclassified, on December 3, 2010, as "Supplemental". Thestudy was initially reclassified as "Invalid" based on clothianidin contamination of controls.Further consideration of the entire study revealed that there was useful information in the studyaddendum that could be used to qualitatively describe hive survival following exposure toclothianidin at levels described in the study. These results showed that the majority of hivesmonitored, including those exposed to clothianidin during the previous season, survived theoverwintering period. The overwintering results cannot be used quantitatively because crosscontamination of clothianidin in the control hives prevents a comparison between the controlhives and the treated hives as they relate to whole hive parameters. Therefore, the finalclassification for the clothianidin honeybee field study is "Supplemental".In this field study, control and treated plots were each 1 hectare in size and paired, so that 4 siteswere established with a formulation control plot paired with a clothianidin-treated plot. Theseplots were separated by a minimum of 250 m. The major source of uncertainty is the ability ofthis study to discriminate treatment-related effects because clothianidin residues were detected innectar from formulation control colonies. In addition, no negative control was reported todetermine if there were statistically significant effects due to the formulation (actives plus inertsminus clothianidin). The presence of clothianidin residues in albeit a limited number of controlhive nectar samples at concentrations similar to those detected in nectar from colonies placed intreated fields suggests that at least some workers from control colonies foraged on clothianidintreated canola. According to the study authors, the minimum distance between the treated andcontrol fields was 250 m and was likely insufficient to prevent cross-foraging of bees betweentreated and control fields. In addition to the close proximity of treated and control fields, controlbees may have foraged in clothianidin-treated fields because the forage in some of the controlfields was of lower quality due to insect damage and reduced emergence of canola. Likewise, theextent to which bees in treated fields may have availed themselves to untreated canola isuncertain given the close proximity of the control fields. Additionally, the study did notadequately evaluate the exposure bees to canola via pollen identification analysis. Additionalconfounding factors associated with overall colony health included the loss of queens from 11colonies, including three colonies that were classified as "dead" part way through the study andnot included in "some" of the statistical analysis. Finally, raw data were not provided in thestudy to conduct a statistical reanalysis of the study resultsBased on the confounding factors associated with potential clothianidin cross-contamination ofnectar from control hives and the lack of a negative control, the results of the investigation of thepotential long-term impact of clothianidin seed-treated canola on honeybees are not adequate foruse in risk assessment. Under the conditions tested, the study indicates that clothianidin residueswere brought back to the bee colonies in nectar and pollen and were found in comb honey aswell; residues were not detected in comb wax though. The study addendum on the assessment ofoverwintering colonies provides useful information on the subsequent effects of bee colonies inthe year following exposure at measured residue concentrations. In summary, this field toxicitystudy with honeybees (OPP Gdln. No. 141-5; OPPTS 850.3040) is classified as "supplemental".Table 1. Ecological data requirements for clothianidin.MRIDGuidelineStudyClassification)Remarks469078-01469078-02(addendum)850.3040SupplementalThis study and associated addendum assessed the toxicity ofclothianidin to pollinators using whole hive parameters underfield conditions. The study does not satisfy the 850.3040guideline.1OPPIN Classifications:Acceptable/Guideline; Acceptable/Non-Guideline; Cited; Confirmatory; Decision Deferred; Extraneoussubmission; In Review; No Decision; Partially Acceptable; Supplemental; Unacceptable/Guideline;Unacceptable/Non-Guideline; Upgradeable.