Charge Question

presented by: Donna Randal

FIFRA SCIENTIFIC ADVISORY PANEL

Consultation

October 25-26, 2011

U.S. Environmental Protection Agenc

Office of Pesticide Programs

Washington, DC
Charge Question 1: Introdu

Focus: TERRA model’s attributes and the general canecessary for modeling pesticides used in urban settinThe three most prevalent antimicrobial uses of copper inpaints, roofing shingles and wood preservatives. The AnDivision used a basic field scale modeling approach, incuse rates, realistic heavy rainfall events, the assumption rates, and storm-water conveyance via impervious surfacpotential high end aquatic exposure from copper’s use as pesticide in roofing shingles and treated wood. The AmCouncil (ACC) has proposed the TERRA Model as an amore refined way to assess aquatic exposure due to the tantimicrobial uses of copper, in wood preservatives and shingles, on a watershed scale level. 
Charge Question 1: (a) and 

Focus: TERRA model’s attributes and the general canecessary for modeling pesticides used in urban settin

a) What does the Panel believe are the advantages and

assessing antimicrobial uses of copper from roofing wood preservatives with TERRA, a spatially-explicscale model? Are there other models that the Panel considered for use by OPP in estimating exposure tuse as an antimicrobial pesticide, specifically in roowood preservative?

b) In the opinion of the Panel, what attributes of an urb

model are the most critical and why does the Panel attributes as critical? Does the TERRA model possattributes?
Charge Question 1: (c) and 

Focus: TERRA model’s attributes and the general canecessary for modeling pesticides used in urban settin

c) Please discuss whether TERRA has the modeling c

necessary for it to be applied to other urban metal eassessments for antimicrobial pesticides as well as wmodifications, if any, would be needed to assess exmetals used as pesticides. 

d) In the opinion of the panel what further developmen

assessment is necessary to prepare the TERRA modexposure assessment tool by the EPA? 
Charge Question 2: Introdu

Focus: Goodwin Creek Watershed and the national apwatershedEPA employs a tiered strategy to assess aquatic exposurefacilitates the rapid screening of pesticide uses for potentithe second tier refines exposure estimates by utilizing a fisite specific properties. This process is designed to incordata (e.g., site specific properties) for each progressive tiehistorically employed field scale models to assess aquatic of national pesticide registrations. The TERRA model, uused by OPP, is a fully distributed, spatially-explicit watemodel capabilities of distributing differences in hydrologproperties, and pesticide uses across a watershed. These require consideration in terms of the proper scale of the e
Charge Question 2: (a) and 

Focus: Goodwin Creek Watershed and the national awatersheda) Are the appropriate pathways (e.g. engineered water 

structures) for modeling urban antimicrobial uses of Goodwin Creek scenario currently included in the frTERRA model? What, if any, additional pathways appropriately assess exposure?

b) What are the most important attributes to consider w

designing an urban watershed modeling scenario? Ithe Panel, where does the Goodwin creek watershed distribution of the nation’s urban watersheds? Alsomodel does not account for storm drains, how does watersheds nationwide?
Charge Question 3: Introdu

Focus: CalibrationWatershed-scale models require calibration to account fowatershed-dependent hydrology and environmental fate pcalibrations have been conducted by altering saturated hyconductivity, Mannings N, soil erodibility factors, land cochemical partitioning coefficients. In contrast, the OPP fsuch as PRZM/EXAMS are not calibrated for site-specifiThe TERRA model utilizes a simulated urban watershed to the hydrology and sediment loads of Goodwin Creek. Goodwin Creek watershed is a predominately pastured/fothe EPA has concerns that the calibration processes may represent urban hydrologic and chemical transport proces
Charge Question 3: (a) and 

Focus: Calibrationa) Please discuss the implications of watershed land use 

model calibration. What types of impacts could these estimated exposure concentrations of copper?

b) Please indicate any unique calibration issues that sho

when simulating an urban, residential watershed.