Blue Mountain Horticultural Society

Annual Meeting

Walla Walla Watershed 

2009 Pesticide Monitoring Summary

Kevin Masterson, DEQ

(503) 229-5615

masterson.kevin@deq.state.or.us

February 2, 2010

Presentation Overview

• Background on Monitoring Program and 

Related Activities

• 2009 and Historical Monitoring Results 

Æ Organophosphate Insecticides

• Results from Testing of Expanded List of 

Pesticides

• Plans for 2010 and Beyond

Water Monitoring Context:

Pesticide Stewardship Partnerships

Using collaborative 

partnerships, local 

expertise and voluntary 

actions to produce 

measurable water quality 

improvements

Everyone’s Goal:

General decrease in pesticide 

levels in streams over time

Pesticide Stewardship Partnership 

Approach

Monitor for current use pesticides in 

surface waters from drift & runoff

Identify streams with elevated pesticide 

concentrations

Collaborate to implement voluntary 

best management practices

Follow-up monitoring to determine water quality 

improvements over time

Walla Walla Project Began in 2005

• Walla Walla Basin Watershed Council

– Water sampling, weather stations, outreach

• OSU Extension & Blue Mountain Hort Society

– Technical assistance, training and implementation

• Oregon Department of Environmental Quality 

– Laboratory analysis, data evaluation & communication

• Oregon Department of Agriculture

– Technical support

• US EPA 

– Grant funding support

Related Stewardship Activities

2006-2009

• Weather Stations

• Technical assistance 

– e.g., March 2007 Spray 

Calibration Workshop

• Waste Pesticide & 

Empty Container 

Collection Events

– 18,000 lbs of pesticides

– 6,000 lbs of empty 

containers for recycling
Pesticide Monitoring in Watershed 

• Monitoring Locations

– 4 mainstem Walla Walla River 

– 1 on Little WW River in town (at “Frog’)

– 4 on “distributaries” in orchard areas

• Typical monitoring period Æ late March - June

• In 2009 pesticides tested increased from 12 to 

over 100 

– New ones include herbicides & fungicides with 

multiple uses

– New lab methods resulted in higher detection limit 

for OPs

Organophosphate Monitoring

• Chlorpyrifos (Lorsban) and Azinphosmethyl (Guthion) of primary interest

– In-Stream Standards at very low levels

– Still found in watersheds throughout state

• Diazinon and Dimethoate 

– Detected regularly in previous years

– Few recent detections of both in the Walla 

Walla watershed

Walla Walla Basin - 2009 Azinphos-Methyl Detections

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

4/2/094/6/09

4/10/094/14/094/18/094/22/094/26/094/30/09

5/4/095/8/09

5/12/095/16/095/20/095/24/095/28/09

6/1/096/5/096/9/09

6/13/096/17/096/21/096/25/09

Azinphos-Methyl (ug/L)

Little WW River, West Branch/Crockett

Little WW River, Midwest Prong

W. Prong Little WW River, S. Stateline Rd

East Little WW River, N. of Stateline Rd.

WQ Standard
Walla Walla Watershed:

Number of Detections Above Standards/Guidance Values*

2006 2007 2008 2009

Chlorpyrifos 

(Lorsban)

12 7 7 8

Azinphos-Methyl 

(Guthion)

14 3 6 10

Diazinon 8 1 10

* Chronic aquatic life values (OAR 340-041-0033)

Walla Walla OP Insecticide Monitoring:

Summary of 2009 Findings

• Levels of chlorpyrifos (Lorsban) increased in Little 

WW distributaries after 2 years of steady declines

• Azionphos-methyl (Guthion) still detected multiple 

times above standard (0.01 ug/l) in distributaries

• Diazinon not detected* & 1 dimethoate detection

• No 2009 Walla Walla River detections of OPs 

– 3 chlorpyrifos detects in 2008 w/ lower detection limit

• 4 low level detections of herbicide Simazine

– Can accentuate impacts of OPs

* 2009 lab detection limit higher than in previous years

New Pesticides Analyzed in 2009

• Over 100 pesticides analyzed 

• 14 detected in Walla Walla Watershed

– 4 from historical suite Æ 3 OPs + Simazine

– 10 from new analytical suite

• No water quality standards exist the 10 

newly analyzed pesticides detected

• Multiple registered uses for 10 new ones 

– Many likely not originating from fruit orchards

Detections of New 2009 Pesticides in 

Walla Walla Watersheds

Insecticides

• Endosulfan sulfate (breakdown product):

– 1 detection = 0.032 ug/l

– Little WW River, West Branch/Crockett

• Carbaryl:

– 13 detections, Max = 0.135 ug/l

– All in various Little WW Distributaries

• Imadicloprid:

– 1 detection = 0.040 ug/l

– Little WW River, West Branch/Crockett

Detections of New 2009 Pesticides in 

Walla Walla Watersheds

Herbicides

• Diuron

– 46 detections, max = 1.26 ug/l

– 2 at WW River at Pepper’s Br. & remainder in distributaries

• Bromacil

– 1 detection = 0.038 ug/l

– E. Little WW River, N. Stateline Rd.

• Terbacil

– 2 detections, max = 0.077 ug/l

– Little WW River, West Branch/Crockett

• Dacthal

– 1 detection = 0.025 ug/l at WW River, Grove School

Detections of New 2009 Pesticides in 

Walla Walla Watersheds

Fungicides

• Propiconazole

– 2 detections, max = 0.070 ug/l

– Little WW River at West Branch/Crockett

• Pyraclostrobin

– 9 detections, max = 0.019 ug/l

– Little WW River distributaries

Miscellaneous

• DEET

– 4 detections, Max = 0.064 ug/l

– All in Little WW Distributaries
Summary of “New” Pesticide 

Findings in Walla Walla

• Results provide a baseline for future monitoring

• EPA Office of Pesticide Benchmarks can be 

used as general screening levels

– 2009 results all below draft benchmarks

– Inter-agency state team (ODA, DEQ, ODF, State 

Health) also assessing benchmarks

• Unknown issue Æ additive and synergistic 

effects of multiple chemicals in water

Possible future Partnership Actions:

2010 and Beyond

• Maintain most of existing monitoring network to 

track improvements

• Consider moving one or two monitoring sites to 

other areas in the watersheds (i.e. other land uses)

• New pesticide stewardship training and assistance 

opportunities ...?

• Identify funding for additional waste pesticide 

collections

• Others?