pesticides and water quality in washington state

Washington State Department of AgricultureWashington State Department of Agriculture

Presented at the CMER Science SessionOctober 25th, 2016

George R. Tuttle MSNatural Resources Assessment Section

Pesticides and Water Qualityin Washington State

Monitoring Activities

The Natural Resources Assessment Section (NRAS) is WSDA’s research group:

We monitor the interface between agricultural practices and natural resources

Gather agricultural land use, pesticide use, and nutrient use data

Conduct surface and ground water monitoring projects

Work cooperatively with partners to meet WSDA’s mission of promoting agriculture while protecting the environment

Highlighted Project:

2015 Study: The Effectiveness of Riparian Vegetation at Intercepting Drift from Aerial Pesticide Application

Types of Pesticides Detected in 2015

The program currently monitors for 153 pesticide analytes…

1

1

1

6

19

14

38

80

Synergist

Wood Preservative

Insect Repellent

Degradate

Insecticide

Fungicide

Herbicide

All CatagoriesTotal

In 2015, 38 different herbicides were detected one or more times

Individual Pesticide Detections in 2015

Detections of herbicides accounted for 51% of all detections in 2015…

7

18

27

95

258

413

845

1663

Synergist

Wood Preservative

Insect Repellent

Degradate

Insecticide

Fungicide

Herbicide

All Catagories

So, why do we see so many herbicide detections? Pesticide use Climate Water solubility Pest pressure

Total

Active Ingredient # of Detections in 2015 Detection Frequency

Diuron 143 42%

2,4-D 87 26%

Dichlobenil 76 22%

Glyphosate 54 77%

Terbacil 52 15%

Metolachlor 48 14%

AMPA 46 66%

Imazapyr 37 11%

Triclopyr 37 11%

Bentazon 30 9%

Dicamba 23 7%

Simazine 23 7%

Isoxaben 19 6%

Bromacil 18 5%

MCPA 17 5%

15 Most Frequently Detected Herbicides

Active Ingredient Pesticide Category

Number of

Detections Above

Criteria

Number of

Detections in 2015

Azoxystrobin Fungicide 1 70

Bifenthrin Pyrethroid Insecticide 4 4

Captan Fungicide 4 8

Chlorpyrifos Organophosphate Insecticide 18 18

Malathion Organophosphate Insecticide 1 1

Metolachlor Herbicide 2 48

Pyridaben Insecticide 1 1

Sulfometuron methyl Herbicide 1 10

There were 32 detections of current use pesticides that approached or exceeded an aquatic life benchmark or water quality standard in 2015

Exceedance Summary

2015 Streamside Vegetation Study

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The concept for this project was a collaborative effort between NMFS & NRAS

Objective: Determine how effective streamside vegetation is at reducing pesticide loading to streams.

Control Sites - without dense woody vegetation

vs.

Vegetated Sites - with dense woody vegetation

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Riparian vegetation

Malathion

Aerially applied

Spotted wing Drosophila

Blueberries

5 Sites

• 2 control

• 3 vegetated

8 Application events

• 4 control

• 4 vegetated

2015 Streamside Vegetation Study

UD1 (Control Site)

2015 Streamside Vegetation Study

Site specific and event specific data:

Application method

Weather

Stream bank geometry

Vegetation characteristics

Pesticide deposition

Pesticide surface water concentration

over time

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FT1 (Vegetated Site)

Study Design

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Measurements collected at 6 equally spaced transects

Instream Measurements

• Geometry

• Shading

• Habitat

Vegetation Measurements

• Width

• Height

• Canopy cover

• Species composition

General water chemistry

Flow

Study Design

Depositional Samples:• Filter paper mounted on

platforms• Water• Vegetation edge• Field edge

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UD1 (Control Site)

WV

F

Study Design

Water Samples– Standing water

• Grab samples collected at each transect before and after

– Flowing water

• Automated samplers placed upstream & downstream

• Composite samples, four 100mL subsamples collected every 6 min.

12Auto Sampler + Depositional Sampler, Downstream position at FM2

Study Design

Weather Station• Wind speed & direction

• Temperature

• Humidity

• Solar radiation

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Averages for Waterbody and Vegetation Measurements

Site Comparison

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Site TypeMean Vegetated

SitesMean Control

Sites

Canopy Angle (°) 71.79 0

Instream Canopy Cover (%)

85.76 45.72

In Vegetation Canopy Cover (%)

95.62 0

Bankfull Width (m) 6.66 4.86

Buffer Width (m) 6.61 n/a

Buffer Height (m) 5.72 n/a

Upstream of FM2 (Vegetated Site)

Site Comparison

15Error Bars Represent One Standard Deviation *Two-Sided Sites

5.9 7.4

12.914.6

19.4

0

2

4

6

8

10

12

14

16

18

20

22

UD1* UD2 FM1 FM2 FT1*

Control Vegetated

Dis

tan

ce (

m)

Average Distance from Field-edge to Water

Water Results

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– Only one control site had enough water to sample due to severe drought

– Concentration of malathion on the water samples were compared EPAs aquatic life criteria:• Endangered Species Level of Concern for Malathion: 1.65 µg/L

– No exceedances were detected at the vegetated sites

– Only exceedances occurring at control site*

* It is important to note that the control site was a very shallow water body with little to no flow in contrast to the vegetated sites

Site Type Site ID Event Sample Type Average (µg/L) Max (µg/L) Detections

Control UD1

1Grab – Before < 0.05 < 0.05 0 of 6

Grab – After 4.14 7.1 7 of 7

2Grab – Before 0.08 0.21 3 of 6

Grab – After 3.45 7.8 6 of 6

Deposition Results

1. Was there a statistical difference between deposition at vegetated and control sites?

2. If yes, what buffer characteristics had an effect on malathion deposition and by how much?

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Deposition Results

Contracted with Washington State University, Department of Mathematics and Statistics

Todd Coffey, PhD, developed a linear mixed model to test if deposition at veg. sites was statistically different from deposition at control sites…

Percent reduction from field-edge (F) to water (W) for all applications

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Deposition Results

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The model showed that Canopy cover, canopy angle, distance from F - V and, distance from F – W all had significant inverse relationships with instream malathion deposition

Todd also then used univariable analysis to test which site characteristics had the greatest effect on instream malathion deposition

The analysis showed that distance between the field and vegetation and canopy cover had the strongest influence

The model also shows that the instream malathion deposition could be further decreased by approximately 26% by either:

Increasing the distance between the field and veg. by an additional 0.6 m(or)

Increasing the canopy cover by an additional 9%

Conclusions

Malathion deposition was significantly reduced at vegetated sites

Dense woody vegetation significantly reduces instream deposition

Canopy cover and distance are significant factors in reducing

deposition

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Take Home Message

Vegetated buffers as narrow as 15 feet that have good canopy cover (≥76%) can reduce pesticide loading to streams via drift during helicopter applications by as much as 97%

This study monitored pesticide applications where the no-spray buffer requirement on the label was only 25 feet

A study like this could be replicated in forestry to address uncertainties and public perception

Acknowledgements

• NMFS Pesticide BiOp team: Tony Hawkes, Scott Hecht, Cathy Laetz, Thomas Hooper, and David Baldwin

• Todd Coffey-Dept of Mathematics and Statistics at WSU

• Blueberry Producers in Whatcom

• Aaron Bagwell, Whatcom Farmers Co-Op

• Kyle Blackburn and Essential Flight Ops, LLC

• Washington Blueberry and Red Raspberry Commissions

• Steve Thun and Rick Jordan, Pacific Agricultural Labs

• Heather Hansen, Washington Friends of Farms and Forests

• EPA Office of Pesticide Programs staff

• Bernalyn McGaughey and staff, Compliance Services International

• Spray Drift Issue Management Team members, Crop Life America

• John Hanzas, Stone Environmental

• Paul Whatling, Cheminova

• Harold W. Thistle, USDA Forest Service

• Tim Bargar, U.S. Geological Survey

• Vince Hebert, Washington State University

• WSDA staff: Abigail Nickelson, Jaclyn Hancock, Joel Demory, Kelly McLain, Brian Scott, Margaret Drennan, George Tuttle, and Rod Baker.

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NRAS Contact Information:

George Tuttle

Agency Toxicologist

360.902.2066

gtuttle@agr.wa.gov

http://www.agr.wa.gov/PestFert/NatResources/

Kelly McLain

Western Area Supervisor

Pesticide Use Lead

360.902.2067

kmclain@agr.wa.gov

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