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July 2010

Estimating Chemical Conce

Urbanized Watersheds us

Mark Velleux, Paul Paquin

Aaron Redman, and Robert Sa
Our Focus: Antimicrobial P

 Antifoulants, biocides wood prese Differ from agricultural pesticides

“[D]etermining human and ecologicaexposure to antimicrobial pesticides different types of measurements and those needed for pesticides largely aand other plants.”

 Consider antimicrobial copper us

products...
Setting: Homogeneous vs. He

 Agricultural Use:

 Farm fields Uniform application

 Building Products:

 Urbanized areas Spatially variable! biocide mass released not 

equal to mass installed

 Address variability with 

watershed approach
TREX Watershed Mo

Two-Dimensional Runoff, Ero

(Velleux et al. 2008) 

       

http://www.engr.colostate.edu/~pierre/ce_old/Projects/TREX%20Web%
Case Study: Antimicrobia

 Examined two separate copper uses:

 Algae-resistant (AR) shingles (e.g. Cu2 O) Treated wood (e.g. CCA, CA, ACQ, etc.)

 Uses and setting differ from agricultura

 Urban setting with spatially-variable landsca Rainfall-driven releases from roofs, decks, f Lake setting with marina and inputs from up

 Simulated copper transport and fate to 

estimated environmental concentration

 Excess copper in surface water, sediment, a
Setting Based on a Real W

Location: 

Goodwin CreBasin Size: 

21.4 km2 (5,1

Landcover: 

Grassland, pLandcover wrepresent an Database: 

14 stream gaModel Resolu

R. Rojas, 2002 90 m x 90 m (
Urban Setting Develop

 Simulated urban land cover for Goodwi Setting reflects spatial variations in dev

 Includes a range of housing density: 1, 4, &  Percentage of houses with AR shingle roofs 

expected market share information

 Percentage of houses with deck and fences 

Census Bureau statistics and market share 

 Utility pole placement and treatment type ba

Toledo, Ohio urban area

 Expected to represent reasonable maxi
Copper Sources: Urban 

AR Shingle RoofsTreated Wood Deand Fences...

Copper Source Detail
Overall Summary of Copper R

0.1

1

10

100

Shingles CCA Non-CCA CCA 

Release Rates (see legend for units)

Intermittently-Wetted Wood 

(mg m-2 mm rain-1)

AR-shingles 

(mg m-2 mm rain-1)

Contin

(mg m

0.16 mg/m2/mm

0.26 mg/m2/mm

3.2 mg/m2/mm

2.2 mg/m2

Overall: 2.6 mg/m2/mm

Overa

Overall = 20% CCA, 80% non-CCA
Environmental Benchmarks 

 Surface water:

 Biotic Ligand Model (BLM) Water quality for regional sites Values vary by month

 Sediment:

 Equilibrium sediment guidelines 

(ESG) (USEPA, 2000)

 Copper as excess metal Assume 5% organic carbon in 

sediment

 Soil:

 Empirical relationships (Rooney et al. 

2006)

 Used local soil chemistry data
Results for Algae-Resistan

 TREX was used to perform simulati

individual storm events over a 10 y

 Daily average EECs calculated for s

and also in soil and sediment
Copper from AR Shingles Over 1

 Over 10 yea

 Mean = 0 St Dev =  Min = 0 μ Max = 7.1 

 Cu releases driven by rainfall 10% of Cu release goes to 

stream, 1% exported

 EECs at watershed outlet Water benchmark: time variable
Copper from AR Shingles After 

     
Copper from AR Shingles After 10 

     
EECs and Benchmarks: AR 

and Benchmarks: AR 

Media

Concentration

Mean St Dev Min Max 

Urban Setting

Water 0.25 0.79

0 7.1 

Sediment 6.7 4.9 1.0 34.5 

Soil 1.7 1.5

0 8.8 

Aquatic Setting (includes marina)

Water 0.23 0.06

0 0.42 

Sediment 0.14 n/a n/a n/a 

Notes: Surface water benchmarks are time variable to refldifferences over time. Ranges of values also vary to refleexpressed as upper window, average, and lower window vrepresent an average condition for six sites.
Simulated Copper Mass Fate: 

 Over 

 90%  10%  9%  1% 

 Most 

becauthe di

 Once 

coppesurfacsignif

Algae-Resistant ShinglesTreated Wood (Decks, Fences, Poles)
Benchmark Exceeda

Note: For surface water, three benchmarks were evasensitive); (2) average; and (3) lower (more sensitivethe number of days in 10 years when dissolved coppgreater than the benchmark for that day. An exceedyears (3-4 days in 10 years) or less is typically consi

Biocide AR Shingles TSetting Urban Aquatic Urba

Surface Water 

Upper Average Lower

Zero Zero Zero

Zero Zero Zero

Zero 

2 days in 1

64 days in 1

Sediment Zero Zero Zero 

Soil Zero Zero Zero 
Outcomes

 Results are expected to be conservativ

 Settings include high-end estimates for den

on land surface and in stream

 Low TSS and low Kp maximize dissolved co

 Generally low EECs consistent with low 

 Very low effective application rates compare

uses: 0.15–0.32 lbs/acre/year vs. 1–16 lbs/ac

 Simulated EECs similar to measurements in 

(Boulanger and Nikolaidis, 2003)

 Simulated EECs much lower than measured 

with high application rates (Fernández-Calv
Copper Application Rate C
Our Interpretation

 For both urban and aquatic settings, EE

expected to exceed benchmarks for mo

 Where EECs do not exceed benchmark

not likely to pose significant environme

 For treated wood, surface water EECs m

lower window benchmark values in urb

 Potential for exceedances driven by conser Such conditions are unlikely to occur for mo

density and environmental conditions.

 Overall, copper use in shingles and trea

likely to pose unacceptable environmen
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Any Questions?
Extra Slides

Results for Treated W

(Decks, Fences, and Util
Copper from Treated Wood Over 

 Over 10 yea

 Mean = 0 St Dev =  Min = 0 μ Max = 16

 Cu releases driven by rainfall 10% of Cu release goes to 

stream, 1% exported

 EECs at watershed outlet Water benchmark: time variable
Copper from Treated Wood After 

     
Copper from Treated Wood After 

     
EECs and Benchmarks: Tre

and Benchmarks: Tre

Media

Concentration

Mean St Dev Min Max 

Urban Setting

Water 0.58 1.7

0 16.7 

Sediment 14.1 9.4 2.1 66.8 

Soil 3.8 4.9

0 31.8 

Aquatic Setting (includes marina)

Water 0.68 0.15 0.001 1.1 

Sediment 0.40 n/a n/a n/a 

Notes: Surface water benchmarks are time variable to refldifferences over time. Ranges of values also vary to refleexpressed as upper window, average, and lower window vrepresent an average condition for six sites.
Copper Release Rate: AR 

0.1

1

10

100

1000

10000

1.E+00 1.E+01 1.E+02 1.E+03 

Cumulative Rainfall (mm)

Cumulative Copper Release (mg m-2)

Palo AltoHoustonHomesteadHagerstownMeanU95%L5%

Short-Term (Palo Alto) 

Study

1 test panel, 3 months

Mean = 0.52 mg m-2 mm-1
Extra Slides

Determination of Copper Re
Copper Sources: Treated Wo