UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

OFFICE OF 

CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

MEMORANDUM 

SUBJECT: 

FROM: 

THRU: 

TO: 

November 16, 2015 

PC Code: 014504 

DP Barcode: 429170 

Review of Public Response to Mancozeb Problem Formulation 

Allen Vaughan, Entomologist [[tJ.v- ~- ii / JL--

Environmental Risk Branch S 1{r"I' ( 

Environmental Fate and Effects Division (7S07P) 

Mah Shamim, Branch Chief 

Environmental Risk Branch S 

Environmental Fate and Effects Division (7S07P) 

Tracy Perry, Team Leader, RMIB3 

Pesticide Re-evaluation Division (7S08P) 

EFED has reviewed the comments received from the Mancozeb Task Force and the Physicians 

Committee for Responsible Medicine. The Mancozeb Task Force has commented on issues 

related to requirements for additional honey bee testing currently required for outdoor use 

chemicals. The Physicians Committee has cited existence of an alternative test (OECD 223) for 

oral toxicity to birds, and recommends that this method be used to fulfill the 8S0.2 l 00 FIFRA 

data requirement. The Committee also cites a published source for avian dietary data on 

mancozeb. EFED has responded below to the individual comments. 

Mancozeb Task Force comment regarding requirements for additional honey bee acute 

and chronic toxicity testing: 

The Task Force believes that the Agency should reconsider the need for the pollinator studies 

identified in the Preliminary Work Plan. Mancozeb exhibits very low toxicity in honey bees. In a 

laboratory study conducted by the University of California-Riverside in which Mancozeb (in the 

form of Dithane M4S) was applied directly onto adult honey bees, very li ttle toxicity was 

observed. The EPA categorizes pesticides as "Toxic to bees" if they cause greater than 50% 

mortality in adult bees exposed up to 11 micrograms per bee, which technically speaking means 

that the LOSO is less than 11 micrograms/bee. In this study, the contact LOSO for Mancozeb was 

reported as greater than 178.87 micrograms/bee, the highest dose tested. In a subsequent report 

by the same authors, honeybees exposed to Dithane M-4S at 193.38 micrograms/bee (at a 

nominal purity of 80% a.i., that is equivalent to l S4.7 micrograms mancozeb active ingredient) 

experienced only 3. 7% mortality, no different from random variation in control bees. 
Confirming the fi ndings of the laboratory studies, Atkins et al. published a summary of 120 

honey bee field and laboratory studies conducted by the University of Ca lifornia Ri verside from 

1950 to 1971 on nearly 60 pesticide formulations, one of which was Di thane M -45. The 

conclusion of the review was that Di thane M-45 can be considered "Relatively nontoxic" and 

"Can be used around bees with a minimum of injury." 

EFED Response: The Mancozeb Task Force has cited a number of studies showing that 

mancozeb is relatively nontoxic to adult bees in acute contact studies. However. acute toxicity 

testing with adult bees does not necessarily reflect potential toxicity to developing larvae or 

chronic toxicity to adult bees. In order to conduct Tier I assessment of pollinator risk, chronic 

effects to adults and larval bees are considered. The registrant may wish to consult the Office of 

Pesticide Programs Guidance for Assessing Pesticide Risks to Bees implemented June 23, 2014 

regarding determination for testing needs and assessment of exposure potential currently used by 

the Agency. 

Physicians Committee for Responsible Medicine comment regarding avian acute oral 

toxicity testing requirement 850.2100. 

We reconunend that OECD Test Guideline 223, Avian Acute Oral Toxicity Test, be used as the 

protocol instead of EPA Guideline 850.2 100 in the interest of reducing the numbers of animals 

used by up to 61 %. We also refer the registrant to the "Guidance for Classifying Studies 

Conducted Using the OECD Test Guideline 223 (TG223) (Acute Avian Oral Sequential Dose 

Study)" available on the Agency's website. 

EFED Response: For studies with bobwhite quail and mallard, the Agency will accept testing 

under OECD Guideline 223. EFED generally recommends against the use of OECD 223 for 

passerine species, as this guideline has not been tested or validated for passerines. 

Physicians Committee for Responsible Medicine comment regarding avian dietary toxicity 

testing requirement 850.2200. 

We found the following data which may fulfill the Agency's needs without additional testing. 

"Mancozeb is slightly toxic to birds, with reported dietary LC50 values in bobwhite quail and 

mallard ducklings of greater than 10,000 ppm. The I 0-day dietary LC50 values of 6400 ppm 

and 3200 ppm are reported for mallard ducks and Japanese quail, respectively." 

EFED Response: The data cited by the Committee are from a secondary source (summary 

document). The document provides only the toxicity values, and does not provide the detailed 

information necessary to allow validation of the data.