# Exposure Modeling Public Meeting

(EMPM)

03

- 24

- 14

1 

# Karen Milians,

Meridith Fry, and Dirk Young

#  Background

 Quality Control (QC) Testing Plan

 PE5 vs. SWCC

 QC Testing Results

 Conclusions

2EX posure A nalysis M odeling S ystem

(EXAMS, Vers. 2.95) V ariable V olume W ater M odel

(VVWM)

PE5 P esticide R oot Z one M odel

(PRZM 5) GUI

P esticide R oot Z one M odel

(PRZM 3, Vers. 3.12) Surface Water

Concentration Calculator

(SWCC)

USEPA , 2013. Young, D. PRZM5 Manual; USEPA, 2013. Variable Volume Water Model. 3USEPA , 2013. Young, D. PRZM5 Manual; USEPA, 2013. Variable Volume Water Model. 

##  SWCC allows more flexibility, user features and

characterization as well as correcting bugs and eliminating

inefficiencies

 SWCC will “behave" like PE5

 Easier to maintain in house

4

##  SWCC output should be similar to equivalent PE5 output

 Modifications are justifiable

 Debugged routines ( e.g. Erosion

, Runoff Parent/Degradate)

 GUI catches errors and program does not crash

 Documentation is clear and adequate

 Overall the SWCC must be easy to use, and intuitive in its

execution

5

## PRZM Scenario Chemical EXAMS scenario

IL corn Atrazine 1 

## Index reservoir

IL corn Fipronil 2 

## Eco

IL corn Captan 3 

## Index reservoir

IL corn X 4 

## Index reservoir/Eco

Criteria

1 

### Relatively persistent herbicide with low sorption.

2 

### Moderately persistent insecticide with moderate sorption.

3 

### Fungicide with rapid degradation and low sorption.

4 

### Relatively immobile compound.

WQTT Advisory Note: Standard Approach for Quality Control (QC) Reviews of PRZM/EXAMS Interfaces and Models. Dated: September 15, 2008. 

### Other scenarios tested:

• CA citrus

• MS cotton

• CA lettuce

• FL carrot

60.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00

Atrazine Fipronil Captan Chem X Peak

4 day

21 day

60 dayOutputvalue fromSWCCOutputvalue from PE5Ratio =

Criteria

Atrazine

- Relatively persistent herbicide (304 days) with low sorption (88 L/kg)

. Fipronil

- mo derately persistent insecticide (33.7 days) with moderate sorption (727 L/kg)

. Captan

- f ungicide with rapid degradation (3.75 days) and low sorption (200 L/kg)

. Chemical X

- moderately persistent (54 days) and immobile compound (4751300 L/kg). 7

## More Impact

Method of Calculating Chronic Concentration

Degradate Fix

T

- Band Application Fix

High Koc input value

Less Impact

Curve Number Implementation

Erosion Correction

8Concentration of pesticidein water (ppb)

Day 1 Day 2 

# PE5 chronic values

Day 3 

# SWCC chronic values

Captan

CA lettuce Water

concentration PE5

( ppb) SWCC

(ppb)

1

- in 10 Peak 6.54 6.54

1

- in 10 4 day 5.43 0.570

1

- in

- 10 21 day 2.82 0.109

1

- in

- 10 60 day 1.13 0.0380 90 1 2 3

PARENT WC (kg/m3)

DEG1 WC (kg/m3)Concentration(kg/m3) • Mass Balance Analysis

• Fundamental parameters were

isolated

• Stable degradate

• Aqueous Aerobic Metabolism half

life of 365 days.

10Parameter PE5 SWCC

Henry’s Law Constant value (HLC) Yes No

Temperature at which degradation

applies Assume 25oC Not only 25oC

Photolysis Reference Latitude (o) Assume 40 Not only 40

Chemical Application Method ( CAM) 1,2,3,

... Presented slightly different

but similar capabilities

Degradates No capabilities Sequential only

Pond/IR Only one at a time Run both simultaneously

Weather parameter Hidden Presented when running the

model

Output report Input and output

values (notepad) Input /output values are

tabulated in tables, graph

with the modeled results and

charact erization in the water

body ( Word doc)

11

###  SWCC output should be similar to equivalent PE5 output

 

### When not equal an explanation was provided

 Modifications are justifiable

 

### Changes were documented and reviewed by WQTT

 Debugged routines

 

### Erosion

, Runoff, Parent/Degradate, Spray Drift, T

- band application,

high Koc input value

 GUI catches errors and program does not crash

 GUI captured all errors and did not crash

 Documentation is clear and adequate

 PRZM5, VVWM and user manual were reviewed by the Team

 Overall the SWCC must be easy to use, and intuitive in its execution

 The team reported SWCC is easy to use 12

##  

# SWCC has been pushed in EFED’s computer

 

# Evaluation period six months was recommended

with revision as needed

 

# Tier I scenario will be developed

 

# Public releases is imminent

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