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WRF Webcast 4537

Improving Water Quality and Consumer

Satisfaction Based on the SMCLs

August 21, 2014

2

USEPA SECONDARY MAXIMUM CONTAMINANT LIMITS: A STRATEGY FOR DRINKING WATER AESTHETIC QUALITY AND

CONSUMER ACCEPTABILITY

Principal Investigator: Andrea Dietrich, PhD

August 21, 2014 Funded by Philadelphia Water Department Water Research Foundation Project #4537

3

Why This Project? • Secondary Maximum Contaminant Levels

recognized as important parameters impacting customer perception of drinking water quality

• Variable state regulations

• Philadelphia Water Department and Andrea Dietrich supported a summary document.

• WRF supports their efforts through the Facilitated Research Program

4

Taste and Odor Control – 48 projects • A Decision Tool for Earthy/Musty Taste and Odor Control (WRF Project

#3032, 9/13)

Manganese – 21 projects • Guidance for the Treatment of Manganese (WRF Project #4373)

SMCLs as a Research Topic

5

MANGANESE AS A RESEARCH TOPIC

Aluminum Chloride Color Copper

Corrosivity Fluoride

Foaming agents Iron Manganese

Odor pH Silver Sulfate

TDS Zinc

Andrea M. Dietrich, Ph.D. Professor, Civil and Environmental Engineering Adjunct Professor, Food Science and Technology

Improving Water Quality and Consumer Satisfaction using Guidance from the SMCLss

Presentation copyright A.M. Dietrich 2014

• Professor, Civil & Environmental

Engineering, Virginia Tech

• Adjunct Professor, Food Science &

Technology

• Co-director, VT‟s Water INTERface

Interdisciplinary Graduate Education

Program

• Chair, International Water

Association‟s Specialist Group on

Off-Flavours in the Aquatic

Environment

• Past chair, American Water Works

Association Taste and Odor

Committee

• Author of over 100 peer-reviewed

journal articles and book chapters

• Author of technical reports for the

Water Research Foundation,

AWWA, utilities, consultants,

industry, and government

• Instructor for Introduction to

Environmental Engineering,

Environmental Chemistry, Water for

Health, and Techniques for

Environmental Analysis

• Research areas water quality;

sensory analysis of environmental

contaminants, odorants, and

tastants; water treatment; potable

water infrastructure; fate and

transport of organic and inorganic

chemicals.

7

Dr. Andrea M. Dietrich - Brief Bio [email protected]

• When promulgating the SMCLs, the USEPA (1979)

stated: “The absence of taste and odor in water

helps to maintain the consumer’s confidence in

the quality of their drinking water …”

• Consumer judge tap water by taste, odor, color,

and appearance

• SMCLs are primary concern of consumers

• Since SMCLs generally treated as guidelines,

receive less attention than PMCLs

Environmental and Water Resources

Civil and Environmental Engineering

Motivation

8

• Consumers

• Water treatment

• Sensory science

• Bottled water

• Source water quality

• Salinity, Algal T&O episodes, chemical spills

• SMCLs need to evolve!

9



Most SMCLs are 35-50 years old!

Since inception, these have evolved:



• Water that is • Clear

• Colorless

• Relatively odorless

• Tasty

• Not CHANGING- • CONSISTENCY!!!!

Photo credit: AM Dietrich

What instills consumer confidence?

10

• Aesthetic - taste, odor, color, foaming

• e.g., TDS, chloride, sulfate

• Cosmetic - human appearance

• fluoride and silver

• Technical - corrosion, staining, scaling, sediment

• e.g., corrosivity, pH, iron



USEPA SMCLs Categories

11

Outline: 15 SMCLs

• Total dissolved solids (TDS)

• Major anions and cations

• Cl-, SO4=

• Minor anions and cations

• Cu, Fe, Mn, Al, Zn, Ag, F

• Odor

• Other Aggregate parameters

• pH, corrosivity, color, foaming agents Environmental and Water Resources

Civil and Environmental Engineering 12

Total dissolved solids (TDS)

Cl-

• Aggregate

measure of

anions & cations

• Salinity

• Overall indicator

of water quality

SMCL = 500 mg/L TDS

• Aesthetic and Technical

• Sources: rocks and minerals

• TDS gives water good taste

• Variable consumer liking

• SMCL consistent with current

science

• Importance of TDS increasing

as source water TDS

increases

14




Context for TDS SMCL

Water Type TDS, mg/L

Human Drinking Water

USEPA SMCL Accepted globally

< 500

< 1,500

Freshwater 0 to ~ 5,000

Brackish Water 5,000 - 30,000

Saline water 30,000 - 50,000

Brine <50,000

15



16

TDS in Ground Water on the RISE



USGS: Methods for Evaluating

Groundwater Quality Data in the

United States, 1988–2010

Severe drought increases TDS in

drinking water

17 Environmental and Water Resources


Cl-

Desalination



Corrosive!

No

Nutrition!

18

When can consumers detect

changes in TDS?

• Increase TDS from low TDS water more readily

detected than decrease TDS from high TDS water

• Room temperature > > chilled water

• Types of ions important

• Chloride > Sulfate

• Sodium > Calcium

19

20



Mineral Typical

Concentration, mg/L Hard Water Soft Water

Ca2+ 50 11

Na+ 15 6

Mg2+ 10 1.5

Cl- 24 10

HCO3- 125 25

SO4= 115 20

TDS 100-400 25-100

SMCL

SMCL

Consider

SMCLs

Major cations and anions

contributing to TDS

Anion - Cation charge balance

SMCL = 250 mg/L Chloride

• Aesthetic- salty taste; Technical- corrosion

• Sources: natural and anthrophogenic

• In 1979, lower value considered by USEPA

• In 21st century, increasing TDS in source waters

• Consumers do not prefer chloride

• Consider lower SMCL for taste & corrosion

21


Civil and Environmental Engineering www.columbus.gov

http://www.columbus.gov/

Sodium – consider SMCL • Aesthetic – salty taste

• Sources: natural and anthropogenic

• 1980s- established Na+ as cause of “salty” (not Cl-)

• Anion affects taste: Cl- >SO42-

• USEPA Advisory 30 - 60 mg Na/L for taste

• Consider establishing SMCL

22


Civil and Environmental Engineering www.columbus.gov

http://www.columbus.gov/

SMCL = 250 mg/L Sulfate

• Aesthetic- salty taste

• Sources: natural, anthropogenic

• Can be major contributor to TDS

• Sulfate is a laxative; health advisory 500 mg/L

• SMCL consistent with current science

23



SO42-

Hardness - Consider SMCL

24

USGS Map

• Aesthetic: bitter taste of Ca and Mg

• Technical - scaling

• Sources

• Natural

• Desalination

• Remineralization




Select TDS References (reverse chronology)

• Dietrich AM. 2014. USEPA SMCLs: A Strategy for Drinking Water Quality and Consumer

Acceptability. Denver, CO.Water Research Foundation. 56 pp.

• García V, Fernández A, Medina ME, Ferrer O, Cortina JL, Valero F, Devesa R. 2014. Flavour

assessment of blends between desalinated and conventionally treated sources. Desalination and

Water Treatment DOI:10.1080/19443994.2013.875943.

• Dietrich AM, Gallagher CD. 2013. Consumer ability to detect the taste of total dissolved solids. J.

American Water Works Association 105(5):E255-263.

• Platikanov S, Garcia V, Fonseca I, Rullán E, Devesa R, Tauler R. 2013. Influence of minerals on the

taste of bottled and tap water: A chemometric approach. Water Research 47:693-704.

• Lindsey BD, Ruppert MG. 2012. Methods for Evaluating Temporal Groundwater Quality Data and

Results of Decadal-Scale Changes in Chloride, Dissolved Solids, and Nitrate Concentrations in

Groundwater in the United States, 1988–2010. Reston VA:United States Geological Survey, 47..

• Devesa R, García V, Matía L. 2010. Water flavor improvement by membrane (RO and EDR)

treatment. Desalination 250(1):113-117. Devesa R, García V, Matía L. 2010. Water flavor

improvement by membrane (RO and EDR) treatment. Desalination 250(1):113-117.

• Gallagher CD, Dietrich AM. 2010. TDS and temperature affect consumer taste preferences. OpFlow

36(11):20-22.

• Deb A, McCammon SB, Snyder J, Dietrich AM. 2010. Impacts of Lining Material on Water Quality

[Project #4036] Denver, CO.Water Research Foundation. 181 pp.

• Burlingame GA, Dietrich AM, Whelton AJ. 2007. Understanding the taste of tap water. J. American

Water Works Association 99(5):100-111.

• Biggs J, Thomure T, Arnol K, Cotton C. 2007. Public outreach tool used in determining customer

preferences of water aesthetics. In: Proceedings of the AWWA Water Quality Technology

Conference. Charlotte, North Carolina, November 4-8, 2007.

25

Select TDS References (reverse chronology) • Dietrich AM. 2006. Aesthetic issues for drinking water. Journal of Water and Health, 4 (supplement

1):11-16.

• USEPA (U.S. Environmental Protection Agency). 2003a. Drinking Water Advisory: Consumer

Acceptability Advice and Health Effects Analysis on Sodium.

www.epa.gov/safewater/ccl/pdf/sodium.pdf. EPA 822-R-03-006, Washington DC.

• Taste and Odor Committee of the American Water Works Association. 2002. Options for a Taste and

Odor Standard. J. American Water Works Association 94(6):80-87.

• Lawless HT, Rapaki F, Horne J, Hayes A.2003. The taste of calcium and magnesium salts and

anionic modifications. Food Quality and Preference 14:319-325.

• Matia L. 1995. Treatment of tastes in drinking water: Causes and control. In: Advances in Taste-and-

Odour Treatment and Control, Edited by I.H. Suffet Joel Mallevialle, Elizabeth Kawczynski Denver,

CO:American Water Works Association Research Foundation and Lyonnaise des Eaux.

• Bruvold WH, Daniels JI. 1990. Standards for mineral content in drinking water. J. American Water

Works Association, 82(2):59-65.

• Pangborn RM, Percore SD. 1982. Taste perception of sodium chloride in relation to dietary intake of

salt. American Journal of Clinical Nutrition 35(3):510-20.

• Murphy C, Cardello AV, Brand JG. 1981. Tastes of fifteen halide salts following water and NaCl:

Anion and cation effects. Physiology and Behavior 26(6):1083–1095.

• Zoeteman, BCJ, de Grunt FE, Köster EP, Smit KBJ, Punter PH. 1978. Taste assessment of

individual salts in water - methodology and preliminary findings by a selected national panel.

Chemical Senses 3(2):127-139.

• Pangborn RM, Bertolero L. 1972. Influence of temperature on taste intensity and degree of liking of

drinking water. J. American Water Works Association 64(8):511-515.

• Bruvold WH. 1968. Scales for rating the taste of water. J. Applied Psychology 52(3):245-253.

26



Audience participation

• In the past two years

(Aug 2012 - Aug

2014) how many

“salty” or “mineral”

taste episodes/events

occurred at your utility

that resulted in

consumer complaints?

27

• A. None

• B. Few (1-3)

• C. Several (4-6)

• D. Many, >7

• E. Do not know

Minor anions & cations

Consumers describing the taste of ferrous

Taste + Odor = Flavor

Flavor can be easily altered by changing the

odor associated with a taste

Iron and Copper Have FLAVOR- lipid

oxidation in the oral cavity produces volatile

odors

Same reaction as keys in your hand


Civil and Environmental Engineering Photo credit: AM Dietrich 29

• Aesthetic – metallic flavor, color

• Technical – corrosion, blue-green staining

• Sources: copper pipe, brass

• 1.3 mg/L Cu = PMCL

• Population threshold 0.4 - 0.5 mg Cu/L

• Some do not taste >8 mg/L

• Soluble flavor; particulates little flavor

• Chemical monitoring to protect human health

• Consider lower SMCL for flavor - 0.4-0.5 mg/L

30



SMCL = 1 mg/L Copper Photo credit: AM Dietrich

• Aesthetic – flavor of Ferrous Fe2+

• Technical – color/rust of Ferric Fe3+

• Sources: natural, iron pipe corrosion

• Population threshold 0.03 - 0.17 mg Fe2+/L

• Individual thresholds 0.007 to >14 mg Fe2+/L

• 0.3 mg/L Fe3+ readily visible in cup

• Reconsider SMCL as Fe causes detectable

metallic flavor at 1/10 the current SMCL

31



SMCL = 0.3 mg/L Iron Photo credit: AM Dietrich

• Aesthetic = bitter, metallic taste

• Technical = black color, deposits

• Sources: natural

• Update SMCL as Mn(II) and Mn(IV) do not

cause metallic taste

• Reconsider SMCL as color/particles detectable

in cup at 0.005 mg/L MnO2

32



SMCL = 0.05 mg/L Mn


SMCL = 0.05 to 0.2 mg/L

Aluminum

• Technical & Aesthetic

• Sources: alum, cement

• 0.05 mg/L = Treatment goal

• 0.2 mg/L avoids color

• Taste at > 4 mg/L


33




• Aesthetic – metallic, astringency

• Technical - corrosion

• Sources: galvanize pipe

• Astringent mouth feel at 5 mg/L Zn

• 5-30 mg/L Zn milky appearance or surface

scum when boiled


34



SMCL = 5 mg/L Zinc


• Cosmetic – gray eyes, skin (argyria)

• Sources: disinfectant, nanosilver

• Increased use of nanosilver a concern


35



SMCL = 0.1 mg/L Silver

Ag+ Ag+ Ag+

• Cosmetic- tooth discoloration and pitting

• Sources: natural and additive

• In 2011 USEPA and HHS recommended

0.7 mg/L F- added as guidance for

fluoridation

• Reconsider SMCL as new guidance

suggests range at ~0.7 mg/L F-

36



SMCL = 2 mg/L Fluoride

F- F- F-

Select References, Cu, Fe, Mn (reverse chronology)



• Sain A, Griffin A, Dietrich AM. 2014. Assessing taste and visual perception of Mn(II) and Mn(IV) in

Drinking Water. J. American Water Works Association 106(1):E32-34.

• Sain A, Dietrich AM. 2014. Rethinking aesthetic guidelines for manganese and iron in drinking water.

J. Water Supply: Res. Technol. – AQUA, accepted.

• Stanford BD, Wright B, Routt JC, Debroux JF, Khan, SJ. 2013. Water Quality Impacts of Extreme

Weather-related Events. Denver, CO: Water Research Foundation.

• Ömür-Özbek P, Dietrich AM, Duncan SE, Lee YW. 2012. Role of lipid oxidation, chelating agents,

and antioxidants in metallic flavor development in the oral cavity. J. Agricultural and Food Chemistry

60(9):2274-2280.

• Ömür-Özbek P. 2012. Global Taste and Odor Survey of Water Utilities: Final Report to the American

Water Works Association from the Taste and Odor Committee. Denver, CO: AWWA.

• Benson AS, Dietrich AM, Gallagher DL. 2012. Evaluation of iron corrosion release models for water

distribution systems; Critical Reviews in Environmental Science and Technology 42(1):44-97.

• Ömür-Özbek P, Dietrich AM. 2011. Retronasal perception and flavor thresholds of iron and copper in

drinking water. J. Water and Health 9(1):1-9.

• Ayotte JD, Gronberg JM, Apodaca LE. 2011. Trace Elements and Radon in Groundwater Across the

United States: U.S. Geological Survey Scientific Investigations Report 2011-5059: Reston, Virginia.

• Mirlohi S, Dietrich AM, Duncan SE. 2011. Age-associated variation in sensory perception of iron in

drinking water and the potential for overexposure in the human population. Environmental Science

and Technology 45(15):6575-83.

37



Select References Cu, Fe, Mn (reverse chronology)

• Hong J-H, Duncan SE, Dietrich AM, O‟Keefe S. 2010 Evaluation of the operationally defined soluble,

insoluble, and complexing copper consumed through drinking water in human saliva. European Food

Research and Technology 231:977-984.

• Hong J-H, Duncan SE, Dietrich AM. 2010. Effect of copper speciation at different pH on temporal

sensory attributes of copper. Food Quality and Preference 21(1):132-139.

• Dietrich AM. 2009. The sense of smell: contributions of orthonasal and retronasal perception applied

to metallic flavor of drinking water. J. Water Supply: Research Technology-AQUA 58(8):562-570.

• Dietrich AM, Cuppett JD, Duncan SE. 2008. How much copper is too much? OpFlow 34(9):8-30.

• Gallagher DL, Cuppett J. 2007. Evaluation of threshold limit methods for sensory data. Water

Science and Technology 55(5): 67-75.

• Epke EM, Lawless HT. 2007. Retronasal smell and detection thresholds of iron and copper salts.

Physiology and Behavior 92:487-491.

• Pizarro F, Araya M, Vásquez M, Lagos G, Olivares M, Méndez MA, Leyton B, Reyes A, Letelier V,

Uauy R. 2007. Biological Trace Element Research 116(2):131-45.

• Kohl PM, Medlar SJ. 2006. Occurrence of Manganese in Drinking Water and Manganese Control.

Denver CO:AWWA Research Foundation, 436 pp.

• Burlingame GA, Lytle DA, Snoeyink VL. 2006. Why red water? Understanding iron release in

distribution systems. Opflow, 32(12):12-16.

• Cerrato JM, Reyes LP, Alvarado, Dietrich AM. 2006. Effect of PVC and iron materials on Mn (II)

deposition in drinking water distribution systems. Water Research, 40(14):2720-2726, 2006.

• Cuppett JD, Duncan SE, Dietrich AM. 2006. Evaluation of copper speciation and water quality factors

that affect aqueous copper tasting sensitivity. Chemical Senses 31(7):689-697.

38



Select References Cu, Fe, Mn (reverse chronology)

• Dietrich AM. 2006. Aesthetic issues for drinking water. J. Water and Health, 4 (supplement 1):11-16.

• Booth S, Brazos B. 2005. Qualitative Procedures for Identifying Particulate Matter in Distribution and

Tap Waters, Awwa Research Foundation, Denver, CO. 164 pp.

• Koseki M, Fujiki S, Tanaka Y, Noguchi H, Nishikawa T. 2005. Effect of water hardness on the taste

of alkaline electrolyzed water. Journal of Food Science 70(4):S249-S253.

• Keast R. 2003. The effect of zinc on human taste perception. J. Food Sci., 68:1871-1877.

• Kirmeyer GJ, Friedman M, Martel K, Thompson G, Clement J, Frey M. 2002. Guidance Manual for

Maintaining Distribution System Water Quality. Denver, CO.Awwa Research Foundation and

American Water Works Association, 325 pp.

• Young W, Horth H, Crane R, Ogden T, Arnott M. 1996. Taste and odour threshold concentrations of

potential potable water contaminants. Water Research, 30(2):331-340.

• Hettinger TP, Myers WE, Frank ME. 1990. Role of olfaction in perception of non-traditional „taste‟

stimuli. Chemical Sense 16:755-760.

• Mallevialle J, Suffet IH (eds). 1987. Identification and Treatment of Tastes and Odors in Drinking

Water. Denver, CO:American Water Works Association, 387 pp.

• Griffin AE. 1960. Significance and removal of manganese in water supplies. J. American Water

Works Association 52(10):1326-1334.

• Cohen JM, Kamphake LJ, Harris EK, Woodward RL. 1960. Taste threshold concentrations of metals

in drinking water. J. American Water Works Association 52(5):660-670.

39 Environmental and Water Resources


“Water companies are teaching their

workers, and even their consumers, to

identify and report funny tastes and

odors. Sensory analysis (using taste

buds and noses) can find all sorts of

water problems – sometimes faster than

lab tests- and even save lives.”

Odor

• Aesthetic - odor

• Sources: MANY

• Reconsider TON method

• Dilution method; time consuming

• Does not correlate with consumer complaints

• Possible replacements

• Flavor Profile Analysis (FPA) (Standard Method 2170)

• Total Intensity of Odor Method

41



SMCL = TON < 3

• Reconsider odor SMCL to provide specific

guidance for select odorants

• Base on consumer feedback or sensory analysis

• California: 0.005 mg MTBE/L standard

• 10 ng/L guidance for geosmin and 2-methylisoborneol

• Philadelphia, PA

• Australia

• Japan

• Metropolitan WDSC

• Monitor with either chemical or sensory methods

42



SMCL = TON < 3

Geosmin 2-Methylisoborneol

• Reconsider odor SMCL to implement method to

assess new materials uses in distribution and

premise plumbing

• Migration of odors from new materials

• Migration methods exist

• Food and Beverage packaging

43



SMCL = TON < 3


Audience participation

• In the past two years

(Aug 2012 - Aug 2014)

how many ODOR

episodes/events

occurred at your utility

that resulted in

consumer complaints?

44

• A. None

• B. Few (1-3)

• C. Several (4-6)

• D. Many, >7

• E. Do not know

Select References for Monitoring Odors (reverse chronology)



• Ömür-Özbek P. 2012. Global Taste and Odor Survey of Water Utilities: Final Report to the American

Water Works Association from the Taste and Odor Committee. Denver, CO: AWWA.

• APHA (American Public Health Association), American Water Works Association (AWWA), Water

Environment Federation (WEF). 2012. Standard Methods for the Examination of Water and

Wastewater, 22nd ed. (Rice EW, Baird RB, Eaton AD, Clesceri LS. eds.) Washington DC.

• Dale MS, Desrochers RD, Labernik SM. Moylan MS. 2011. Threshold Odor Number versus Flavor

Profile Analysis: a case study in the endeavor to measure consumer acceptance. Presented at the 9th

IWA Symposium on Off-Flavours in the Aquatic Environment, Aberdeen, Scotland, August 2011.

• Desrochers R. 2008. Sensory analysis in the water industry. Journal of the American Water Works

Association 100(10):50-54.

• Durand ML, Dietrich AM. 2007. Contributions of silane cross-linked PEX pipe to chemical/solvent

odors in drinking water. Water Science and Technology 55(5):153-160.

• Gallagher DL, Cuppett J. 2007. Evaluation of threshold limit methods for sensory data. Water Science

and Technology 55(5): 67-75.

• Heim T, Dietrich AM. 2007. Sensory aspects and water quality impacts of chlorinated and

chloraminated drinking water in contact with HDPE and cPVC pipe, Water Research 41:757-764.

• Tomboulian P, Schweitzer L, Mullin K, Wilson J, Khiari D. 2004. Materials used in drinking water

distribution systems: contribution to taste-and-odor. Water Science and Technology, 49(9):219-226.

• Hrudey SE, Hrudey EJ. 2004. Safe Drinking Water Lessons from Recent Outbreaks in Affluent

Nations. London, England: IWA Publishing.

• Dietrich AM, Whelton A, Hoehn R, Anderson R, Wille M. 2004. Attribute rating test for sensory

analysis. Water Science and Technology 49(9):61-67.

45



Select References for Monitoring Odors (reverse chronology)

• Dietrich AM, Hoehn RC, Burlingame GA, Gittelman T. 2004. Practical Taste-and-Odor Methods for

Routine Operations: DECISION TREE. Denver, CO; Awwa Research Foundation, 161pp.

• Schweitzer L, Tomboulian P, Atasi K, Chen T, Khiari D. 2004. Utility quick test for analyzing materials

for drinking water distribution systems for effect on taste and odor. Water Science and Technology

49(9):75-80.

• Marchesan M, Morran J. 2004. Tastes associated with products in contact with drinking water. Water

Science and Technology 49(9):227-231.

• Skjevrak I, Due A, Gjerstad KO, Herikstad H. 2003. Volatile organic components migrating from

plastic pipes (HDPE,PEX and PVC) into drinking water. Water Research 37:1912-1920.

• Dietrich AM, Burlingame GA, Hoehn RC. 2003. Strategies for taste-and-odor testing methods, OpFlow

29(10)10-14; (reprinted in Volume XXVIII, No. 2 (March - April 2004) of the Arab Water World (AWW).

• Khiari D, Barrett S, Chinn R, Bruchet A, Piriou P, Matia L, Ventura F, Suffet IH, Gittelman T,

Leutweiler P. 2002. Distribution Generated Taste-and-Odor Phenomena. Denver,CO:AwwaRF, 340 p.

• Graham M, Najm I, Simpson M, MacLeod B, Summers S, Cummings L. 2000. Optimization of

powdered activated carbon application for geosmin and MIB removal. Denver, CO: AWWA Research

Foundation, 136 pp.

• Rigal S, Danjou J. 1999. Tastes and odors in drinking water distribution systems related to the use of

synthetic materials. Water Science and Technology 40(6):203-208.

• Burlingame GA, Dann RM, Brock GL. 1986. A case study of geosmin in Philadelphia's water. J.

American Water Works Association 78:56-61.

• Mallevialle J, Suffet IH (eds). 1987. Identification and Treatment of Tastes and Odors in Drinking

Water. Denver, CO:American Water Works Association, 387 pp.

• Krasner SW, McGuire MJ, Ferguson VB. 1985. Tastes and odors: the flavor profile method. J.

American Water Works Association 77(3):34-39.

46



Other Aggregate SMCLs

pH

corrosivity

color

foaming agents

• Aesthetic

• < 6.5 bitter, metallic

• >8.5 slippery feel, soda taste

• Technical - corrosion

• Sources: natural, anthropogenic

• SMCL consistent with current science for taste

• Reconsider SMCL - corrosion control at basic pH

48



H+

OH-

SMCL = pH 6.5 - 8.5

• Aesthetic – metallic taste

• Technical – corrosion, corroded pipes/ fixtures

staining

• Reconsider SMCL as no method to directly

measure corrosivity

• SMCLs for chloride, copper, iron, manganese,

pH, total dissolved solids, and zinc can mitigate

aesthetic-related corrosion of metallic materials

49



Corrosivity SMCL = Non corrosive

• Aesthetic – visible tint, color

• Sources: NOM, Cu, Fe, Mn, dyes, industry

• 15 Color Units set where consumers begin to see

• SMCL for true color consistent with current

science

50



SMCL = 15 Color Units


• Aesthetic- taste, odor, color

• Sources: before about 1970,

non-biodegradable

surfactants

• Current standard consistent

with science but is it

needed?

51



SMCL=0.5 mg/L Foaming Agents


Ammonia – Consider SMCL

• Aesthetic – pungent taste and odor

• Sources: natural, chloramines

• T&O data confusing: older, speciation not clear


• Consider guidance from nitrification

52



NH4+ <=> NH3 + H+

Harnessing Consumer Feedback To Improve Water Quality

When promulgating the SMCLs, the

USEPA (1979) stated: “The absence of

taste and odor in water helps to maintain

the consumer’s confidence in the

quality of their drinking water …”

• Consumer judge their tap water by its taste,

odor, color, and appearance

• SMCL parameters are primary concern of

consumers

• Consumer feedback is a useful data stream

that drinking water providers should harness

for water quality

• The water industry should systematically

investigate number and types of water quality

descriptors from consumers

54



Consumers

Consumers WTP personnel 55

Challenging for consumers to

describe odors

Dietrich, Phetxumphou, Gallagher. 2014

• COMMUNICATION

• Consumers need reassurance when water

provider is aware of water quality change

• Consumer and staff training for taste, odor, and

color identification

• Information and educational materials

56



Consumers

Select References for Consumer Complaints Issues (reverse chronology)

• Dietrich AM, Phetxumphou K, Gallagher DL. 2014. Systematic tracking, visualizing, and interpreting of

consumer feedback for drinking water quality. Water Research accepted August 2014.

• Gallagher DL, Dietrich AM. 2014. Statistical approaches for analyzing customer complaint data to

assess aesthetic episodes in drinking water. J. Water Supply: Research and Technology-AQUA,

63(5):358-367.

• Philadelphia Water Department and CH2M HILL. 2013. Philadelphia Water Department

Contamination Warning System Demonstration Pilot Project: Customer Complaints Surveillance

Guidance. White paper submitted to USEPA as part of the Water Security Initiative grant Awarded to

Philadelphia Water Department. Downloadable from www.ch2mhill.com/iws. accessed October 2013.

• Doria M. 2010. Factors influencing public perception of drinking water quality. Water Policy 12:1-19.

• Speight V, Grayman W, Khanal N. 2010 Syngeries between security research and distribution system

water quality management. J. American Water Works Association 102(2):30-33.

• USEPA (U.S. Environmental Protection Agency). 2008. Water Security Initiative: Interim Guidance on

Developing an Operational Strategy for Contamination Warning Systems, EPA-817-R-08-002.

• Jones A, Dewey C, Doré K, Majowicz S, McEwen S, Waltner-Toews D, Henson S, Mathews E. 2007.

A qualitative exploration of the public perception of municipal drinking water. Water Policy 9(4):425.

• Hrudey SE, Hrudey EJ. 2007. A nose for trouble: the role of off-flavors in assuring safe drinking water.

Water Science and Technology 55(5):69-75.

• Lauer, WC. 2004. Water Quality Complaint Investigator's Field Guide. Denver CO: American Water

Works Association. 105 pp.

• Hrudey SE, Hrudey EJ. 2004. Safe Drinking Water Lessons from Recent Outbreaks in Affluent

Nations. London, England: IWA Publishing

• Taste and Odor Committee of the American Water Works Association. 2002. Options for a Taste and

Odor Standard. J. American Water Works Association 94(6):80-87.

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• Keep consumer satisfaction at the forefront

• Understand SMCL-related issues in your system

• Collect and interpret consumer feedback as an

indicator of water quality

• Develop education materials for sensory issues

• Develop guidance for specific odorants

• Work with regulatory community to change TON

• Work together to develop an industry-wide data

base for gathering data related to the aesthetic,

cosmetic, and technical SMCLs

Recommendations for utilities and

water community

More Information

59



Dietrich AM. 2014.

USEPA SECONDARY MAXIMUM

CONTAMINANT LIMITS:

A STRATEGY FOR DRINKING WATER

AESTHETIC QUALITY AND CONSUMER

ACCEPTABILITY.

Denver, CO. Water Research Foundation.

Acknowledgments

• WRF, especially Kim Linton and Michelle Suazo

for organizing webcast

• Gary Burlingame, Philadelphia Water

Department


Civil and Environmental Engineering 60

QUESTIONS????

61

view the webcast slides

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