Pesticides and Urban Water
Quality in California.
A Stormwater Perspective
Dave Tamayo, Environmental Specialist
Sacramento County Stormwater Program
Chair, CASQA Pesticides Subcommittee
Western Region IPM Ant Workshop
Riverside, CA August 20, 2008
Acknowledgements







Kelly Moran, TDC Environmental
San Francisco Estuary Project
Laura Speare, SF Estuary Project
Geoff Brosseau, CASQA
Bill Johnson, Tom Mumley SFRWQCB
CASQA Pesticides Subcommittee
Loren Oki, Jay Gan. Univ of California
Why do Stormwater Programs
care about pesticides?
Clean Water Act liability for
pesticide toxicity




303d listing
TMDLs
Permit provisions
Citizen suits
Off with their heads!
Phase Out Reduced Diazinon
Levels
in Chollas Creek (San Diego)
Source: City of San Diego, Chollas Creek TMDL Source Loading, Best Management Practices, and
Monitoring Strategy Assessment, prepared by Weston Solutions, September 2006.
Bay Area Diazinon & Chlorpyrifos
Use Decreased from 1999-2003
200,000
Chlorpyrifos
180,000
Diazinon
160,000
140,000
Pounds of
Active
Ingredient
120,000
100,000
80,000
60,000
40,000
20,000
0
1999
2000
2001
2002
2003
BUT…Application of Bay Area
Pyrethroids Use Almost Tripled Between
2001 & 2004 (as measured in permethrin equivalents)
1,200,000
1,000,000
800,000
Bifenthrin
600,000
Cypermethrin
Others
400,000
200,000
0
2001
2002
2003
2004
Estimated use of study list pyrethroids in the San Francisco Bay Area 2001-2004 (permethrin equivalents)
We’ve got problems right now:
Pyrethroids are causing widespread
toxicity in California urban waters.
 Main problem—sediment toxicity
 Some water column samples toxic
 Widespread toxicity found in urban
California streams
– Urban>>Agricultural areas
Hyalella azteca (amphipod)
Locations of pyrethroid
detections and associated toxicity
SWAMP Pesticide Sampling Sites
Pyrethroids observed by
region
Holmes et al 2008
Pyrethroid Toxicity is Statewide
Figure: Holmes et al 2008
Pyrethroid Toxicity in Urban
Creeks is Severe
 Pyrethroids detected in almost 100% of urban
creek sediment samples
 Multiple pyrethroids contribute to toxicity
– Bifenthrin, cyfluthrin & cypermethrin biggest
 Majority of tested creeks have toxicity
 Direct connection to urban runoff shown
 # Toxic units (TUs) varies
– <1 to >20 TU found
– Many samples >10 TU
Source: Publications by Weston et al., urban runoff program data and
California Water Board data.
Photo courtesy California
Water Board
We need to get off the
pesticide merry-go-round.
Where Are More Pesticides
Used in California?
Photo courtesy USGS
Urban Pesticide Facts
 >900 registered pesticide active
ingredients
 >11,000 registered pesticide products
 At least half of California pesticide use is
in urban areas
– Technically, 75% is urban
– About half of urban use
is chlorine & sodium
hypochlorite
Which Pesticide Uses Are Most
Important for Water Quality?
Urban
Runoff
Carries
Pesticides
to Creeks
Figure courtesy SF Bay Regional Water Board, based on U.C. IPM Project drawing
Toxicity Matters:
Permethrin Equivalents
San Francisco Bay Area Study List Pyrethroids Urban Uses, 2003
NonReported
20%
NonReported
40%
ProfessionalStructural
47%
ProfessionalOther
13%
by Active Ingredient
ProfessionalOther
8%
ProfessionalStructural
72%
By Permethrin Equivalents
Almost 90% of Toxicity in
California Pyrethroids Use is in
Urban Areas
Agricultural
12%
Unreported
Urban
24%
Reported
Urban
64%
Estimated use of study list pyrethroids in California, 2004 (permethrin equivalents)
All User Groups Apply
Pyrethroids Outdoors in the SF
Bay Area
ProfessionalStructural
46%
NonReported
39%
Shaded portion
could have
been applied
underground
ProfessionalLandscaping
15%
Estimated use of study list pyrethroids in the San Francisco Bay Area, 2004 (permethrin equivalents)
Myth:
Public outreach is the
solution.
 Outreach is expensive
 10-20% behavior change
 Regulatory action needed
Progress: Pre-construction
termiticides
 Label changes to reduce chance of
sediment runoff
University of Hawaii Termite Project
Progress:
Structural Pest Control Board
New Regulations (pending OAL approval)
 Progressive definition of structural IPM
 IPM training required to get most licenses
 IPM Continuing Education requirements for all
licensees
 Establish statewide IPM Certification program
 Allow promotion of IPM environmental
benefits
Whose job is it, anyway?
This is what EPA says:
“When EPA approves a particular pesticide for
registration, the Agency has assessed the
chemical and found that, when used according
to label directions, it does not pose
unreasonable risk to public health and the
environment.”
http://www.epa.gov/pesticides/regulating/data.htm
Contact
Dave Tamayo, Environmental Specialist
County of Sacramento Stormwater Program
Co-Chair, CASQA Pesticides Subcommittee
916 874-8024
tamayod@saccounty.net
Whose job is it, anyway?
CA Department of Pesticide Regulation





Cannot change EPA label
Establish use restrictions
Pesticide use reports
“Environmental certification”
Re-evaluation