Docket Number EPA-HQ-OPP-2010-0244

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M-Cresol AMENDED FINAL WORK PLAN

The Agency is amending the 2010 M-Cresol Final Work Plan (EPA-HQ-OPP-2010-0244-008) such 

that the anticipated ecological effects data consist of the following three studies:

 (GLN 850.1010) Acute aquatic invertebrate, Daphnia magna

 (GLN 850.1075) Acute fish, estuarine/marine fish, Menidia sp.

 (GLN 850.2100) Acute avian oral, upland game bird

These changes reflect 1) reduction in the amount of avian data anticipated as needed to perform a 

hazard assessment; 2) corrections to what appears in the m-cresol: Product Chemistry/Environmental 

Fate and Ecological Effects Scoping document (EPA-HQ-OPP-2010-0244-004) to be differences 

between the list of anticipated ecological effects data section versus the data justification tables 

provided in Appendix B; and 3) modification of fish species required based on consideration of 

ecological effects structure activity models for m-cresol.

In the 2010 M-Cresol Final Work Plan and m-cresol: Product Chemistry/Environmental Fate and 

Ecological Effects Scoping document, two avian ecological effects studies were anticipated to be 

required for registration review, one an avian acute oral and the other an avian subacute dietary study. 

Testing with only one species, an upland game bird—the northern bobwhite quail was anticipated for 

both study types. The Agency identified in the 2010 m-cresol: Product Chemistry/Environmental Fate 

and Ecological Effects Scoping document that registration review would require only a hazard 

assessment, rather than an ecological risk assessment. For purposes of conducting a hazard assessment 

rather than an ecological risk assessment only the avian acute oral study is critical. Therefore the 

Agency is removing the avian subacute dietary data requirement (Guideline 850.2200) for m-cresol. 

In the m-cresol: Product Chemistry/Environmental Fate and Ecological Effects Scoping document

acute fish testing with both a freshwater species and an estuarine/marine species was anticipated to be 

required for registration review. Testing with a freshwater species, the rainbow trout, was identified as 

anticipated in the main body of the scoping document, but additional testing of an estuarine/marine 

species, the Atlantic silverside was also identified in Appendix B (EPA-HQ-OPP-2010-0244-004). 

The estuarine/marine acute fish requirement was missed in the 2010 M-Cresol Work Plan, only the 

freshwater species was identified. The Agency estimated acute 96-h LC50 m-cresol values for a 

freshwater and estuarine/marine fish using a structure activity relationship model, ECOSAR 

(version(v) 1.11). The estimated m-cresol values from ECOSAR (v1.11) of 16.6 ppm and 7.5 ppm for 

a freshwater and a saltwater fish, respectively, are based on relationships observed with phenolic 

compounds. This relationship indicates that estuarine/marine fish species may be more sensitive than 

freshwater fish for such compounds. The 96-h LC50 value is close to the Agency’s current pesticide 

hazard labeling standard of 1 ppm. Given how close the estuarine/marine acute value is to the hazard 

standard and the degree of uncertainty in the phenol structure activity relationship (SAR) model 

(ECOSAR v1.11 On-line Help for Phenols), the Agency still anticipates requiring fish acute testing but 

only with the more sensitive estuarine/marine fish taxonomic group. The preferred test species is a 

silverside (Menidia sp.).

The other anticipated ecological effects data requirement in the 2010 M-Cresol Final Work Plan and 

the 2010 m-cresol: Product Chemistry/Environmental Fate and Ecological Effects Scoping document

was for a freshwater daphnid. The Agency evaluated if the structure activity relationship model, 

ECOSAR (v 1.11) could provide a reasonable acute 48-h EC50 value for daphnid, rather than testing. 

The estimated m-cresol value from ECOSAR (v1.11) of 5.2 ppm is based on relationships observed 
Docket Number EPA-HQ-OPP-2010-0244

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with phenolic compounds. Given how close this value is to the hazard standard and the degree of 

uncertainty in the phenol structure activity relationship (SAR) model (ECOSAR v1.11 On-line Help 

for Phenols) for daphnids, the Agency still anticipates requiring a freshwater acute daphnid study with 

m-cresol. The preferred test species is still Daphnia magna. 

Per 40 CFR part 152 there are a number of ways registrants can submit information to meet a data 

requirement. One way is generation of a new valid study (40 CFR §152.92), but alternatively the 

registrant can meet a data requirement per 40 CFR part 152.94 by citing, and submitting to the Agency 

a valid study from the public literature. The Agency is aware that there are m-cresol ecological effects 

data in the public literature for Daphnia magna per information obtained from EPA’s 

ECOTOXicology database (ECOTOX version 4 [http://cfpub.epa.gov/ecotox/quick_query.htm]) and 

information cited in ECOSAR (v1.11) for development of the phenol SAR. The Agency has not 

reviewed the validity of these studies for registration review purposes. If the registrant obtains these 

studies, they can be submitted to meet the anticipated data requirement for daphnids.

Summary of Data Requirements

A summary table of the data required to support the registration review of m-cresol is presented below.

Anticipated Data Requirements for the Registration Review of M-Cresol (PC code 022102)

Guideline 

Number

Anticipated Data Requirement Test 

Material

Estimated Timeframe 

(Measured in months 

from DCI receipt)

835.2120 Hydrolysis of parent and degradates as a function of pH 

at 25 C

PAI 12

850.1010 2 Aquatic invertebrate acute toxicity, test, freshwater 

daphnids

PAI 24

850.1075 3 Fish acute toxicity test, estuarine marine PAI 18

850.2100 1 Avian acute oral toxicity test PAI 12

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Unless otherwise stated by the Agency, all other elements of the Agency's December 2010 m-cresol

FWP remain unchanged.

 

1 Results from a study using one upland game bird is required. Preferred specie is a bobwhite quail. OECD TG 233 

using the “LD50- Slope test” or “limit dose test” can be used instead of OCSPP 850.2100 for certain species and 

conditions (e.g., causes no delayed effects, causes no regurgitation?. Details on the species and conditions under 

which TG 233 would not fulfill the data requirement are described at 

http://www.epa.gov/pesticides/science/efed/policy_guidance/team_authors/terrestrial_biology_tech_team/revi

ew_avian_acute_oral_oecd_tg223.htm

2 Results from a study using one freshwater daphnid species are required. Data are preferred on Daphnia magna. 

3 Results from a study using one estuarine/ marine fish species must be submitted to satisfy this requirement. 

Preferred species is a Menedia species.