Plumbing Materials: Impacts on Drinking Water Quality and Consumer Willingness to Pay
Civil & Environmental Engineering: Andrea Dietrich, Marc Edwards, G. V. Loganathan … Food Science and Technology: Susan Duncan
Agriculture and Applied Economics: Darrell Bosch … Institute for Community Health: Sharon Dwyer … Virginia Water Center: Tamim Younos … Biological Sciences: Joseph Falkinham
PhD Students: J. Cerrato, J. H. Hong, E. Kleczyk, J. Lee, P. Omur-Ozbek, E.Tanellari, Y. Zhang
MS Students: J. Cuppett, A. Dudi, M. Durand, A. George, T. Heim, H. Johnson, J. Ladd, N. Murray, C. Nguyen, S. Triantafyllidou
Undergraduate Students: S. Abbot, A. Galvis, M. Greenfield, J. Nicholson, K. Robbins, A. Strickhouser,
Montana State University, Civil & Environmental Engineering: Anne Camper
NSF # DMII 0329474
2. Impact of Plumbing on Odor and Quality of Drinking Water
Interdisciplinary Connections
In short-term leaching test for the plumbing materials, cPVC imparted the fewest organic compounds to the water, consumed
the least amount of disinfectant, and had few noticeable odors. All other polymer materials imparted distinct odors and organic
chemicals, and consumed residual disinfectant. Copper pipe consumed nearly all the residual disinfectant. These effects
were most prominent in the first 2 months of material use.
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Fears? Facts?
Aesthetics/
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CORROSION!!
Analyt. Chem
Health Issues
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Costs of
Materials,
Treatments,
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Risk Communication
Detection / Perception
New Models for Plumbing
ODORS
Materials Science
and Performance
Our interdisciplinary study of materials used in drinking water
infrastructure answers inextricably interwoven questions about drinking water conveyance,
quality of water at the tap, and “real” costs of household plumbing. Our multi-prong
approach integrates: Biochemistry of Materials Degradation and Water Quality, Aesthetics
and Analytical Chemistry of Corroded Materials, and Economics, Health and Perception in
Consumer Decision-making. A portion of our results are presented here, including: 1)
fundamental understanding of chemical corrosion and human response to copper in
drinking water; 2) an understanding of how changes in disinfectant type and natural
organic matter (in response to current EPA regulations) will alter materials performance to
impact water quality, biological stability and aesthetics; and 3) gaining consumer input on
home plumbing and its failures. Other aspects of this project include investigating lead in
drinking water, evaluating microbial growth in pipes and hot water heaters, and
development of tools for use by policy makers and citizens to make informed decisions.
WATER
QUALITY
1= minor
5= major
impact
Consumer Health and
Aesthetic Issues
0
0.1 0.25 0.5
1
1.3
Gastrointestinal illness
2
3
mg/l of total copper
4
6
8
gasoline-like
pleasant-sweet
alcohol
sweet, burning, chemical
sweet-tarry
sweet-tarry
citrus, floral
bad, aldehyde
model, glue
hydrocarbon
bad, aldehyde
sweet solvent
citrus, floral
Plumbing Material
>8
Increased Odors –
sensory annoyance
Organic Carbon Release –
food for microorganisms
Chlorine Consumption –
loss of disinfectant
Chloramine Consumptionloss of disinfectant
Microbiological Growth
HDPE
PEX-a
PEX-b
Epoxy
Copper
1
5
2
5
3
3
1
1
2
5
3
1
1
2
1
1
5
5
1
2
1
1
5
5
2
3
3
3
2
2
Between 45 and 50% of those interviewed were willing to pay an “additional” positive amount for leak-free plumbing materials,
with Midwest having the highest percentage. Those who were unwilling to pay more varied from 25 to 30%.
Additional
Amount Willing
to Pay ($)
COSTS
mg/l of soluble copper
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
Some people
never taste copper
WHO Guideline
EPA Action Level _
EPA SMCL
Cumulative % of detection
FLAVOR
and
HEALTH
70
Epoxy
3. Impacts on Consumer Willingness to Pay
We discovered that people taste soluble copper but not copper particles, which readily form in
drinking water. Copper interacts with salivary proteins, has astringent, bitter and metallic tastes,
and produces a retronasal smell. As the copper concentration increases and more particles form,
people are not able to detect the flavor even as it approaches levels that cause illness.
78
PEX-b
gasoline/terpentine
1. Copper Corrosion, Flavor, and Health
73
PEX-a
cPVC
OVERVIEW:
Region where 50%
population can detect
HDPE
Parameter
(short term testing)
Fundamental Science
100
90
80
70
60
50
40
30
20
10
0
cPVC
Costly Repairs and
Water Losses
% Interviewees by Geographical Region
Southeast
Mid West
West
Rest of
U.S.
U.S. Total
0
500
24.8
2.8
27.5
4.6
30.3
4.6
27.2
4.4
27.5
4.4
600
5.5
6.4
4.6
6.4
6.2
700
5.5
5.5
5.5
7.5
7.3
800
7.3
13.8
5.5
10.2
9.6
1200
8.3
4.6
12.8
7.9
8.5
2000
3.7
8.3
5.5
6.2
6.1
4000
11.9
7.3
8.3
4.4
4.9
Don’t Know
28.4
22.0
22.9
25.8
25.5
No Answer
1.8
0
0
0
0
SUMMARY: This interdisciplinary project evaluates interactions of plumbing and water quality to provide
science in support of consumer health and concerns. The results will inform the water industry,
researchers, regulators, and the public on mechanisms to improve drinking water palatability and safety.