## Tier I Exposure Refinemen ts & Tier II T ools f or Assessing Exposure of Bees toP esticides **1** U.S. Environmental Pr otection Agency

Re uben Baris, M.S. Environmental F ate and Effects Division Office of P es ticide Pr ogr ams

# Outline
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### Options fo r r efining Tier I e xposur e es timates when the scr een iden tifies chemicals that need additional ev aluation U.S. Environmental Pr otection Agency **2**

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### Tier II e xposur e st udy descriptionsU.S. Environmental Pr otection Agency **3**

# Pote nt ial Tier I Exposure Refinemen ts
• Purpose: pr ovide an additional lev el of r ealism for conser vat iv e Tier I es timates. • Empirical data that ar e r outinely submitte d as part of re gis tr ation pack ag e that could be use to r efine Tier I e xposur e es timates Ref inemen t options ar e based on a va ilable data alr eady U.S. Environmental Pr otection Agency **4**

• Ref inemen t options ar e based on a va ilable data alr eady submitte d to fulfill data r equir emen ts under FIFRA • Ref inemen ts fo r d ietary ex posur e only • Refinements are based on studies conducted on food commodities • No guideline s tudies ar e curr ently a va ilable to pr ovide additional information for contact e xposur e • If Dietary AND Con ta ct ex posur e e xc eed the LOC, a higher tier analysis is needed.

# Pote nt ial Tier I Exposure Refinemen ts U.S. Environmental Pr otection Agency **5 Study**  **Ty pe**  **Fo liar**  **Applications Soil**  **Applications** Cr opped Te rrestrial Field Dissipation (TFD; OCSPP 835.6100) X X Cr op Field Trial (Magnitude of R esidue Studies; X X OCSPP 860.1500) X X Accumulation in R ot ational Cr ops (OCSPP 860.1850) -- X Natur e of R esidue (Plant Metabolism Studies; OCSPP 860.1300) -- X Plant Uptake and Tra nslocation Te st (OCSPP 850.4800) X X

# Tier II Exposure Studies Purpose: obtain chemical specific , empirically - based ex posur e data relev an t to bees in the field. U.S. Environmental Pr otection Agency **6**

# Tier II Exposure Studies: Objectives
• Re ducing uncert ain ty by using empirical data • Addr essing Tier I assumptions ( e.g. , concentr at ions in tall gr ass = nectar and pollen, consumption r ates) • Exposur e on intended use sites, methods, and patterns • Exposur es ar e quan tified thr ough dir ect spr ayand diet U.S. Environmental Pr otection Agency **7**

• Exposur es ar e quan tified thr ough dir ect spr ayand diet • Shift focus fr om individual bee to whole colon y • Re sidues ma y be measur ed in pollen, nectar , on bees, and/or hiv e pr oducts • Goal is to complete Tier II studies in a manag eable wa y to obtain desir ed information on bee e xposur e • Balancing certainty and uncert ainty

# Tier II Exposure Studies: Limit at ions
• Goal is to g ather important information on chemical specific bee e xposur e in the field
• Uncert ain ties/Consider ations • In - hiv e residues ma y be differ ent than those encountered by bees in the U.S. Environmental Pr otection Agency **8**

• In - hiv e residues ma y be differ ent than those encountered by bees in the field • Addr essing Tier I uncertainties – unpr ocessed food sources • Time and r esour ce allocation • Unknown if r esidues in lea ve s and flower s ar e a conserv at iv e measur e of re sidues in pollen and nectar

# Tier II Exposure Studies: Study Design Ta rgete d Field Study (Field R esidue Tr ial)
• Akin to a monitoring study • Objectiv e is to sample food sour ces r elev an t to bee e xposur es ( i.e. , pollen and nect ar) by quantifying pes ticide r esidues in U.S. Environmental Pr otection Agency **9**
( i.e. , pollen and nect ar) by quantifying pes ticide r esidues in ma trices re lev an t to bees • Option to adapt study design of e xis ting study r equir emen t for pes ticides in pollen and nect ar ( e.g. , Cr opped TFD s tudy) • Sample timing is par amoun t ( e.g ., sampling during bloom when bees should be for aging) • Applicable scenarios include seed tr ea tmen ts, soil applications, and foliar spr ay s

# Tier II Exposure Studies: Study Design Semi - Field Tu nnel Study

• Tr ea te d cr op is kept under an enclosur e (Tunnel) along with a nucleus hiv e of bees Pe st icide concentr ations can be quantified fr om the s tomach U.S. Environmental Pr otection Agency **10**

• Pe st icide concentr ations can be quantified fr om the s tomach conte nt s, pollen sacs, pollen tr aps, and fr om hiv e matrices. • Po llen and nectar could be sampled dir ectly fr om the plant • Applicable scenarios include seed tr ea tmen ts, soil applications, and foliar spr ay s

# Tier II Exposure Studies: Design Considerat ions
• Application methods ar e v ariable • Ta rget high - end e xposur e (ma ximum application) • Cr op selection mus t be r elev an t and attr activ e for bees • Systemic tr ansport is chemical and cr op dependent Plants ma y ha ve dif

fe re nt matrices tha t r epr esent food sources for bees U.S. Environmental Pr otection Agency **11**

• Plants ma y ha ve dif

fe re nt matrices tha t r epr esent food sources for bees ( e.g ., corn vs. canola) • Sampling design is par amoun t • Ta rget maximum concentr at ions found in pollen and nectar • Sample pollen and nectar at differ ent time points during bloom • Sampling to target cr op and application method ( e.g ., fo liar applications sampled on da y - 0; soil applications and dela yed tr ansport) • Climatic and r egional v ariability

# Questions? U.S. Environmental Pr otection Agency **12**