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# Consideration of Pesticide Spray Drift Reduction Technology in EPA Ecological Risk Assessments

Faruque Khan U.S . Environmental Protection Agency

September 20, 20112 

# Motivation for this Work

Overall risk reduction, increased sensitivity to spray drift issues from suburban development and endangered species concerns Development of improved methods, tools, and data for EPA’s risk assessment and risk management for registration decisions Verifying and quantifying a DRT's potential to reduce drift 

### can benefit growers/applicators, manufacturers, public, and the environment The acceptance of a larger variety of DRTs would allow greater flexibility in drift management3 

# Collaborations & Partnerships

U.S. Environmental Protection Agency  Office of Pesticide Programs (OPP)  Environmental Technology Council (ETC)  Environmental Technology Verification (ETV) Program U.S. Department of Agriculture (USDA) Pesticide Manufacturers Stakeholder Groups include: pesticide registrants, adjuvant producers, applicator groups, sprayer manufacturers, academic and government researchers Interest in collaborating with other countries4 

# Overview of DRT Evaluation

Measure of performance in wind tunnels  Droplet size distribution 

## AGDISP model run with measured droplet size spectra under a typical condition 

## Droplet size spectra used to model downwind deposition for aquatic and terrestrial environments Deposition data compared to ASABE S572 reference spectra5 

## Low Speed Wind Tunnel (LSWT) test was

conducted at the EPA’s Aerosol Testing 

## Facility (ATF) in Research Triangle Park, NC High Speed Wind Tunnel (HSWT) test was conducted at the USDA-ARS facility in College Station, TX 

# DRT Protocol Verification Data generation and acquisition were performed 

## with a reference and two candidate nozzles for the following testing scenarios:6 

# Spray Nozzles and Material

NOZZLES Reference Nozzle  ASABE S572, fine/medium boundary  110  flat -fan, 43.6 psi, 0.31 gpm Test Nozzle A  Teejet AI - 11003 VS induction nozzle  Very coarse spray per ASABE S572  43.5 psi, 0.3 gpm Test Nozzle B  Hypropumps ULD 120 - 04 dual air induction nozzle  Coarse spray per ASABE S572  43.5 psi, 0.4 gpm SPRAY MATERIAL Deionized water with 0.25% v/v of a 90% nonionic surfactant Uranine tracer at 3.6 g/L7 

## Comparing nozzles performance relative to a



## reference system Use the ASABE S572 nozzle/category associated with the test DRT atomizer for the reference 

## Concept of a Spray Drift Reduction Factor: (Deposition)

DRT 

### (Deposition)

reference 

# Selection of Reference System

= SD Reduction Factor8 

# High Speed Wind Tunnel Test

Intended for aerial application Critical measurement was droplet size  AGDISP spray drift model was used 

# to estimate downwind deposition Other measurements were monitored for confirming/understanding DRT 

# performance9 

# Droplet Size Spectra for HSWT10 

# AGDISP Modeling11 

# AGDISP Modeling12 

# Comparison of driftable fractions13 

# Estimation of Deposition14 

# Depositions and buffer distances

for aquatic environment15 

# Depositions and buffer distances

for terrestrial environment16 

# Buffer Distance Estimations17 

# Use of Results

The drift reduction associated with a DRTs use could be utilized by EPA to develop spray drift reduction factors Spray drift reduction factors could be incorporated into EPA pesticide risk assessments:  Drinking water assessments 

###  Aquatic organism assessments 

###  Terrestrial plant assessments 

###  Special assessments 

### Allow more labeling options for pesticide products to 

### manage spray drift18 Distance from application site Amount. of drift and risk Level of concern for a pesticide for people, animals, plants 

## Relationship Between Application Technologies, Amount of Drift/Risk, and Risk Management Need for risk management restrictions No DRT DRT* DRT** DRT ***19 

# Summary

Verification test results of DRTs provide an opportunity to evaluate the performance of the draft protocol EPA and pesticide manufacturers could include use of DRTs in risk assessments and on product labels A winner for multiple stakeholders: 

###  Gives greater flexibility and knowledge to growers and applicators to meet or improve on drift requirements 

###  Gives incentives to equipment manufacturers to manufacture/sell DRTs 

###  May lower overall costs of spraying Opportunity to extend similar efforts for future DRT verification program compatible with other countries20 

# URL Links to EPA’s Spray



# Drift and DRT Project http://www.epa.gov/pesticides/factsheets /spraydrift.htm http://www.epa.gov/etv/este.html#pdrt21