1
Evaluation of Water Contamination from
Consumer Product Uses
Rick Reiss
SOT DC Spring Symposium
April 15, 2010
2
Introduction
 Many consumer products are disposed of down
residential drains
 Transported into sewer systems and potentially
released into the environment
 Contaminate waterways leading to risk to aquatic species
 Potentially make its way into drinking water
 Sorb to sludge in sewage treatment plants
 Some sludge is used as biosolids for agricultural amendment
 Potential for terrestrial exposures
3
Factors Affecting Potential Risks




Quantities used
Methods of disposal
Dilution into waterway
Physicochemical properties
 Binding to organic matter
 Aquatic degradation
 Toxicity to aquatic organisms
4
Summary of Reconnaissance Studies
 USGS has performed surveys in streams, surface
water sources of drinking water, and groundwater
 Found a variety of antimicrobials, fragrances, flavoring
chemicals, pesticides, plasticizers, cosmetics, etc.
 However, the low levels of most detections raises
questions about whether there is a risk
 Many potential chemicals have not been measured
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CASE STUDY #1 – TRICLOSAN
AQUATIC EXPOSURES
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Approach
 Triclosan (2,4,4’-trichloro-2’-hydroxydiphenyl ether) is
a broad spectrum bactericide
 Generally low human toxicity, but high toxicity to algae
 Recent studies address estrogenic activity
 Used soaps, detergents, surface cleansers,
disinfectants, cosmetics, pharmaceuticals, and oral
hygiene products.
 Most (~95%) of the uses are disposed of down
residential drains
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Purpose of the Study
 Estimation of the distribution of triclosan
concentrations in reaches following WWTP discharge.
Based on:
 Characteristics of reaches
 Discharge mass from WTTP
 Physicochemical properties
 Estimation of risk to aquatic organisms based on most
sensitive species in phylogenic groups.
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Significant Factor Affecting Loading: Dilution at
Outfall
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Factors Affecting Triclosan Loading into Rivers
 Triclosan loading into river
 Influent concentration
 Removal efficiency in WWTP
 Physical properties of river
 Dilution
 pH
 Suspended sediment concentration
 Organic carbon content of sediment
 Physicochemical properties
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Development of an Aquatic Exposure Model
 Steady-state model accounting for ionization, sorption
with suspended sediment, and complexation with
dissolved organic carbon (DOC).
 Downstream dissipation modeled from results of dieaway studies.
 Probabilistic inputs developed for effluent
concentration, pH, stream velocity, suspended
sediment concentration (including organic carbon
content), and DOC concentration
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Characteristics of Reaches
 EPA’s Clean Water Needs Survey contains extensive
data for WWTP facilities.
 Mean flow, low flow, velocity, pH, and discharge volume
 Of the 16,024 WWTPs in 1996, sufficient data were
available for 11,010 facilities.
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Mean Flow Dilution at WWTPs
100,000,000
10,000,000
Mean Flow Dilution
1,000,000
100,000
10,000
1,000
100
10
1
0
20
40
60
Cumulative Frequency
80
100
13
Low Flow Dilution (One in 10 years)
10,000,000
1,000,000
Low Flow Dilution
100,000
10,000
1,000
100
10
1
0
20
40
60
Cumulative Frequency
80
100
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Triclosan Removal in Wastewater Treatment
Plants
Slough
Meltham
Crofton
Chertsey
West Union - II
Effluent
Influent
West Union - I
Glendale
Loveland
Columbus
0
5
10
15
20
25
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Wastewater Treatment Removal
 Significant removal due to high sorption to sludge
 Removal rates:
 Activated sludge: 94 to 96 percent (4 plants)
 Trickling filter: 58 to 96 percent (4 plants)
 Distribution of U.S. treatment plants: (1) activated sludge:
86%, (2) trickling filter: 12%, and (3) primary treatment: 2%.
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Physicochemical Properties of Triclosan
Property
Value
Molecular Weight
289.6
Water Solubility
12 mg/L
Dissociation constant (pKa)
8.14 at 20oC
Vapor pressure
7x10-4 Pa at 25oC
Partition coefficient (log Kow)
4.8
Aerobic biodegradation in soil
17.4-35.2 day half-life
Aqueous photolysis
41-min half-life at pH of
7 and 25oC
Adsorption to suspended solids (Koc)
47,454 mg/g
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Correlation Between Suspended Sediment and
Organic Carbon Content
Percentage Organic Carbon
100
10
1
0
0
1
10
100
1,000
Suspended Sediment Concentration (mg/L)
10,000
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Triclosan Die-Away Studies
 Triclosan dissipation in an 8 kilometer stretch of Cibalo
Creek in south central Texas (Morrall et al.):
 Half-life, dilution-corrected, was 12.8 hours.
 Half-life, including dilution, was 5 hours
 Measured triclosan dissipation in the River Aire in the
U.K. (Sabaliunus et al.):
 Half-life, including dilution, was 3.3 hours
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Summary of Probabilistic Analysis
 Data on stream characteristics for 11,010 reaches
obtained from Needs survey for both mean and low
flow dilutions.
 Suspended sediment and DOC concentration from
USGS data, and organic carbon content from
correlation.
 Environmental fate properties of triclosan (e.g.,
sorption).
 Die-away rate
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Estimated Concentrations at Discharge Point
600
Triclosan Conc (ppt)
500
400
Mean
Flow
300
Low
Flow
200
100
0
5th
10th
25th
50th
75th
Percentile
90th
95th
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Lowest NOECs Across Species Class
Species
NOEC (ppb)
Acute fish (bluegill sunfish, fathead minnow)
100
Acute aquatic invertebrates (Ceriodaphnia
dubia)
50
Algae (Scenedesmus subspicatus)
0.67
Aquatic plants (Lemna gibba)
62.5
Chronic fish (rainbow trout)
34
Chronic aquatic invertebrates (Daphnia magna)
40
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Margins of Safety at Outfall (Low Flow)
10000
1000
50th
100
90th
10
95th
1
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Margins of Safety 5 Miles Downstream, Low
Dissipation (Low Flow)
100000
10000
1000
50th
100
90th
10
95th
1
24
Margins of Safety 5 Miles Downstream, High
Dissipation (Low Flow)
1000000
100000
10000
1000
100
10
1
50th
90th
95th
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Summary of Case Study
 There should be no direct effects to fish, plants or
invertebrates due to triclosan exposures from WWTPs
 There may be some effects to algae for reaches where
the dilution is low (or when the dilution is low)
 Uncertainties exist regarding degradates of triclosan in
water, particularly due to photolysis
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CASE STUDY #2 – TRICLOSAN
TERRESTRIAL EXPOSURES
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Introduction
 Triclosan has a high potential to sorb with organic
matter
 Sludge is wastewater treatment plants is very rich in
organic matter
 Some wastewater sludge is used as soil amendments
in agriculture
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Exposure Pathways
 Direct exposure
 Earthworms
 Soil microorganisms
 Terrestrial plants
 Secondary exposures
 Consumption of earthworms (birds and mammals)
 Fish exposed in water from wastewater effluent (birds and
mammals)
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Triclosan Concentrations in Sludge
18
16
Concentration (ug/g)
14
Max Value
Used for
12
10
8
6
4
2
0
Primary Secondary Primary
Sludge
Sludge
Sludge
Columbus, OH
Digested
Sludge
Glendale, OH
Primary
Sludge
Digested
Sludge
Primary Secondary Digested
Sludge
Sludge
Sludge
West Union, OH
Location and Type of Sludge
Primary Secondary
Sludge
Sludge
Loveland, OH
1McAvoy
et al. (2002)
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Endpoint Values for Risk Assessment
Species
Value
Birds, acute (bobwhite quail)
LD50 = 862 mg/kg
Birds, subchronic (bobwhite quail)
LD50 = 577 mg/kg/day
Mammals, acute (rats)
LD50 = 3700 mg/kg
Mammals, chronic (hamsters)
NOEL = 75 mg/kg/day
Earthworms
NOEL >1026 mg/kg
Microorganisms
HA50 = 236 mg/L
Soil respiration and nitrification
NOEL = 1 mg/kg
Cucumbers
NOEC = 1 mg/kg (pre-emergent study in
relevant soil)
ED50 = 0.74 mg/kg (shoot dry weight in sand)
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Key Factors in the Exposure Assessment
 Assumed soil amendment rates
 0.5-2.0 kg/m2/year
 Soil degradation rate
 35 day half-life
 Bioconcentration factors in fish and earthworms
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Predicted Environmental Concentrations
0.25
Concentration (mg/kg)
0.2
0.15
0.1
0.05
0
soil
earthworm
EU Default
cucumber
weight
soil
earthworm
cucumber
weight
US Ag-land Typical
soil
earthworm
US Ag-land Upper-Bound
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Margins of Safety for Secondary Fish Exposure
10,000,000
1,000,000
Margin of Safety (log-scale)
100,000
10,000
1,000
100
10
1
Osprey
Belted
EU FishKingfisher Eating Bird
Typical Scenario
Mink
EU FishEating
Mammal
Osprey
Belted
EU FishKingfisher Eating Bird
Mink
Upper-Bound Scenario
EU FishEating
Mammal
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Margins of Safety for Secondary Exposure from
Earthworms
100,000,000
10,000,000
1,000,000
Margin of Safety (log-scale)
100,000
10,000
1,000
100
10
1
Short-tailed EU Worm- Herring Gull American EU Worm- Short-tailed EU Worm- Herring Gull American EU WormShrew
Eating
Woodcock Eating Bird
Shrew
Eating
Woodcock Eating Bird
Mammal
Mammal
Typical Scenario
Upper-Bound Scenario
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Margins of Safety for Terrestrial Plants
1,000
Margin of Safety (log-scale)
100
10
1
Typical Application
Upper-Bound Application
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Conclusions
 Everything must go somewhere!
 Especially things that don’t degrade quickly and/or stick to
organic matter
 Risk assessment methods can be applied to address
potential exposures in aquatic and terrestrial
environments
 Can be used to differentiate real risks from mere exposures