CHALLENGES IN MAINTAININGDRINKING WATER QUALITY AT THE TAP:

CONTAMINATION WITH TOXIC LEAD

Simoni Triantafyllidou

Triantafyllidou.Simoni@epa.gov

University of ArkansasSeptember 14, 2017

1

A little bit about me

• Bachelor’s in Environmental Technical Engineering University of

Crete, Greece

• M.S. in Environmental Engineering• Ph.D. in Civil Engineering

• Environmental Engineer at USEPA’s Office of Research andDevelopment

Outline • Motivation

- Overview of drinking water distribution challenges in the US

• Research Project Examples - Lead (Pb) in water and children’s blood before Flint, MI - Galvanic corrosion after partial lead service line

replacements - Lead in drinking water of US schools and biokinetic

modeling of children’s blood lead levels - In-building disinfection and unintended consequences

3

Paradigm Shift in Drinking Water Quality

Safe Water Safe Water

Tasty Water

+

+

+Sanitary Water Sanitary Water Sanitary Water

Sanitary Water Safe Water Tasty Water

•Waterborne Disease •DBPs/VOCs • Satisfying Consumer

•Disinfection •More Strict Criteria • Aesthetics (Taste and Odor)

•Water Quantity •Water Quality • Distribution System

Korean Ministry of Environment, modified by Jo, 2006 4

Drinking Water Quality AFTER treatment plant

Water Sanitary Water Source Water Treatment Plant Safe Water

Premise Plumbing

niot m

u erib

tsyt SisD

Tasty Water

Sanitary Water Safe Water

Tasty Water ? 5

Aging Main Distribution Systems in the US

http://www.infrastructurereportcard.org

•Many DS reach or have exceededtheir design lifetime

Clogged Iron Pipe due to corrosion http://www.wrb.ri.gov

Water Main Break NACE, 2010

• Public health implications, resource and financial Implications6

Premise plumbing challenges

Every building is a dead-end • Variety of reactive pipe materials that interact with disinfectant and bacteria

-PVC, PEX, Galvanized, Copper, Brass, Solder, Old Lead

• Variety of plumbing configurations, installation practices (good/bad), and maintenance (good/bad)

• Water use patterns affect Water Age - Flow: Continuous Turbulent Long Stagnation - Temperature, Redox Potential, pH, Disinfectant Residual: Highly Variable

- Microbes: Quantifiable diversity 7modified from Marc Edwards

Premise plumbing challenges

Chemistry of water affects end water quality

• All waters are different in terms of corrosivity and microbial re-growth potential, due to pH?

NOM? Alkalinity?

Cor. Inhibitor?

1) Source water quality 2) Water treatment steps 3) Interaction with distribution system before building

• Water that is “aggressive” for corrosion or microbial growth for certain plumbing materials/configurationsmight be “harmless” to next door plumbing - Variability from building to building - Variability from tap to tap (hot spots) - Variability between hot and cold water from same tap

8

Protect water and public health from plumbing…

Blue Water Due to Copper

Rashes from shower/bathing

Red Water Due to Iron (lead also present)

Blood lead poisoning

…Then protect plumbing from water

Leak in Copper Pipe due to “corrosive” water Mold due to Leaks

Expensive Repairs due to Leaks

9modified from Marc Edwards

Research Interests

Drinking Water

Treatment

Inorganic Aquatic

Chemistry

Corrosion Science

Risk Assessment

Sustainable Drinking

Water Infrastructure

10

Useful research tools

Morphology and Visual & XRF elemental mapping of Tap water collection plumbing particles in faucet aerator inspection through SEM/EDS

Analysis of water • pH, temp, chlorine, TDS • Metals (ICP-MS) • Chloride, sulfate, anions (IC)

Excavated lead pipe Analysis of scale mineralogy Lead scale harvesting with XRD, SEM/EDS

11

Useful research tools

Chemical equilibrium modeling

(e.g., Mineql+)

Blood lead modeling for children (e.g., IEUBK)

12

Much of US water safe, but problems remain

Pb not present in drinking water right after treatment:

BUILDING

– Old Lead Pipe Triantafyllidou and Edwards, 2012

– Old Leaded Solder– Leaded Brass (valves, fittings, faucets, water fountains) 13

Washington DC “Lead-in-Water Crisis”

0 10 20 30 40 50 60 70 80 90

100

90%

'ile

lead

in w

ater

(pp

b)

15 ppb EPA AL

Chloramine Disinfectant 2000

Media Coverage Orthophosphate Corrosion Inhibitor, 2004

Public Health Intervention 2004

1999 2000 2001a 2001b 2002 2003 2004 2005 2006 2007 Year

Environmental Science & Technology, 2009 14

Low

Switch from chlorine to chloramine disinfectant dissolved lead from pipe scales

Blood Lead Level (BLL) Database

Birth Date ZIPCODE Collect Date BLL

1/27/1997 20011 1/27/1999 <3

6/16/1997 20010 9/7/1999 9

10/19/1998 20011 9/7/2000 5

. . . .

. . . .

. . . . 12/24/2005 20011 3/19/2007 <1.0

3/18/2005 20011 8/30/2007 12

N > 28,000 16

in High Pb in Water

2001

Compare Median BLL / All Children / City-wide

Low Pb Water

Low Pb in Water

1999 2003 2005

0.0

0.5

1.0

1.5

2.0

Year

log10

(BLL

)

No Increase in Median BLL

2007

17

Same Data Revisited

• Compare incidence of elevated blood lead (Moore et al., 1977)

% children with BLL > 10 ug/dL

• Perform “neighborhood analysis” (Brown et al., 2001)

Compare “High” vs. “Low” Risk neighborhoods, based on:

1) prevalence of lead pipe

2) elevated lead in water

• Focus on sensitive sub-group (WHO, 2000) Children ≤ 30 months of age

18

Increase in Incidence of

Elevated blood lead

at High Risk

High Pb in Water

Compare % EBL / Zip Code Level / Children ≤ 30 months

0

1

2

3

4

5

6

2000 2002 2004 2006

% C

hild

ren

with

El

evat

ed B

lood

Lea

d

Low Risk Neighborhoods

High Risk Neighborhoods

U.S. Trendline

High Pb in Water

3 X

Year Environmental Science & Technology, 2009 19

Results published in Washington Post ES and T in 2009 followed up

http://www.washingtonpost.com/wp-Best paper of 2009 Award dyn/content/graphic/2009/01/27/GR

Science category, Editor's choice 2009012700721.html 20

Conclusion

• Elevated lead in tap water can contribute or even cause elevated lead in blood of children, in cases of sub-optimal corrosion control at the presence of leaded plumbing

21

Galvanic Corrosion after Simulated Small-Scale Partial Lead Service Line Replacements

22

Partial Lead Service Line Replacement (PLSLR) • 3.3 - 6.4 million US

homes with old lead service lines or connections (Weston and EES, 1990)

• Contribute to 50 – 75 % of the lead in drinking water (Sandvig et al., 2008)

• Partial replacementwith copper pipe mandatory remedial measure to meet water lead regulation

Journal AWWA, 201123

r • Electron flow

Water

OH.

CATHODE Cu Protected

pH 1'

REDUCTION 02+4e·+2H20-)40H-

Galvanic Corrosion

• Electrochemical (galvanic) cell between copper and lead pipe

• Drinking water serves as electrolyte

• Galvanic corrosion may accelerate corrosion of the lead pipe

24

Water chemistry can turn on/off galvanic corrosion: CSMR

English studies first introduced the CSMR as a factor controlling galvanic corrosion in connections of lead solder/copper

Oliphant (1983) and Gregory (1985)

Example calculation:

Chloride to Sulfate Mass Ratio( CSMR) = [Cl - ] 12 mg/L Cl - = = 0.6 -2 -2[SO 4 ] 20 mg/L SO4

0% Cu (i.e. 100% Pb) .. (j tt QCP

50°ToCu

,

- --

83% Cu

· 100% Cu 26

Experimental Results 0% Cu 17% Cu 50% Cu 67% Cu 83% Cu 100% Cu

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

Pb in

Wat

er (p

pb)

High CSMR Wires Connected

Low CSMR Wires Connected

High CSMR Wires Dis-Connected

High CSMR Wires Re-Connected

Time (Weeks)

Experimental Results

Pb in

wat

er (p

pb) 25000

20000

15000

10000

5000

0

30000

+8x

+10x

+12x

+14x

0 17 50 67 83 100

Experimental, High CMSR (Galvanic or Deposition Corrosion)

% Pb pipe Replaced with Cu

28Journal AWWA, 2011

Conclusions

• Galvanic connections between copper pipeand lead pipe worsened lead release,compared to lead pipe alone

• High CSMR water released much more lead tothe water than did low CSMR: Water chemistry affects the galvanic battery

• High CSMR produced high sustained galvaniccurrents between lead and copper (notpresented here)

Biokinetic modeling to predict blood lead levels from water lead exposure

Water Air Diet Dust Soil Other

Lung GI Tract

Environmental Lead (Pb) Concentration

1. E

XPO

SURE

2. U

PTAK

E

Lung GI Tract

Plasma Extra-Cellular Fluid

Plasma Extra-Cellular Fluid

Red Blood Cells

Exhaled Air

Feces

Hair, sweat, nails

Urine

3. B

IOKI

NET

ICS

Kidney, Liver, Other soft

tissues

Two Bone Compartment

Predict Blood Lead Level(BLL) in children (Treated as a Geometric Mean- GM)

4. PROBABILITY DISTRIBUTION

Predict % of Exposed Children with Elevated Blood Lead (i.e., BLL > Safety

Threshold)

BLL (ug/L)

Safety Threshold GM

Log-normal distribution around GM with fixed GSD

Prob

abili

ty D

ensi

ty

30

Two school districts with water lead problems

31

Elementary Schools Sampled

Seattle Public Schools (SPS)

63 (~3,100 taps)

Los Angeles Unified School District (LAUSD)

601 (~51,000 taps)

Dates Pre: 2004, Post: 2011-12 2008-2009

Range of Lead Detected, µg/L

<1 - 1,600 first-draw <1 – 370 flushed

0.2 - 13,000 first-draw 0.2 - 7,400 flushed

% school taps > 20 µg/L pre

19% of first-draw 3% of flushed (30 sec)

6% of first-draw 1% of flushed (30 sec)

pre / post RA? Yes / No No / No

Model Input: Combined WLL for one Seattle School, pre-remediation

32

Cum

ulat

ive

Perc

entil

e

100 208 g/L 291 g/L 781 g/L

90

80 39 g/L 45 g/L 160 g/L

70

60

50

40 6 g/L 16 g/L 59 g/L

30

20

10

0 1 10 100

First draw Second draw Combined

1000

Water Lead Level (g/L)

Probability Distributions of BLL, 10 ug/dL threshold

0.30 BLL

50%ile WLL WLL (GM, % Elevated Pb % 'ile (µg/L) µg/dL) EBL (%) 0.25

Prob

abili

ty D

ensi

ty

0.20

0.15

CDC level of concern

90%ile WLL

50 90 99

16 45 208

3.3 5.5

15.3

1.0 10.2 81.6

0.10

0.05

99%ile WLL

0.00 0 10 20 30 40

Blood Lead Level (g/dL)

33

Predicted percentage of children with elevated blood lead

Combined WLL (g/L)

Percentile of Combined WLL

50 60 70 80 90 100

Perc

entil

e of

BLL

Exc

eeda

nce

at G

iven

WLL

0

20

40

60

80

100 BLL threshold: 5 g/dL BLL threshold: 10 g/dL

16 25 45 2643317 In

tegr

ated

Per

cent

of E

xpos

edPo

pula

tion

Exc

eedi

ng

50

40

30

20

10

0

25.5% of children exceed BLL threshold of 5 g/dL

4.6% of children exceed BLL threshold of 10 g/dL

0 2 4 6 8 10 12 14 16

Science of the Total Environment, 2014 BLL Threshold (g/dL)

34

Conclusions

• Variability among fountains within a school

• Variability in water lead contamination among schools receiving the same water

• Accounting for variability in water lead levels, variability in children's response and stringent new public health goals predicted blood lead elevations for most sensitive or most exposed children to water lead

Risk?

x

x

35

Hospitals also deserve increased attention

• A 2011 outbreak of hospital-acquired pneumonia in Pittsburg, from waterborne Legionella bacteria, caused

- Several fatalities and lawsuits - Congressional investigation - Extensive press coverage and criticism - Closer look at microorganisms in hospital water

http://www.cnn.com/2012/12/13/health/legionnaires-hospital-water/ 36

In-building disinfection Thermal disinfection Example: ASHRAE Guideline 12-2000

• Water always stored at > 60°C in water heater > 51°C in hot water lines

• Different instructions after outbreaks or for periodic thermal disinfection

Chemical Disinfection • Chlorine • Copper-silver ionization • Chloramine • UV irradiation • Chlorine dioxide • Ozone

Copper-Silver Ionization (CSI) is one option

Flow cells

Controllers

Inside a “Fresh” Flow cell

Haensel, 2012

Good Maintenance Needed

/Silver

Copper/

• Adds copper ions (Cu+2) and silver ions (Ag+) to water biocides • Only a fraction of copper and silver will remain in free ionic form depending on water chemistry

38

Large Hospital in Cincinnati

CSI • Treated surface water - pH 8.6 - Alkalinity

75 mg/L as CaCO3

- Free chlorine 1 mg/L

• A & B are patient buildings supplied with the CSI-treated water • First hospital in Ohio to be regulated under the Safe Drinking

Water Act due to in-building water treatment

Insufficient Cu and Ag levels reaching hospital taps

Cu in

hot

wat

er (µ

g/L)

CSI Softener A A (N=5 taps) CSI Softener A A (N=5 taps)

40

Min. Intended after CSI

300

250

200

150

100

50

0

Ag in

hot

wat

er (µ

g/L)

10/1

4

Min. Intended after CSI

35

30

25

20

15

10

5

0

5/13

7/13

8/13

1/14

2/14

3/14

5/14

7/14

5/13

7/13

9/13

11/1

3

1/14

3/14

5/14

7/14

9/14

11/1

4

Date Date

Submitted to Water Research, 2016

40

Solubility modeling (Mineql+) for Cu

Total Cu Cu(OH)2(s)

Cu+2

CuCO3(aq)

Total Cu = Cu+2 + CuCO3(aq)

41

Solubility modeling (Mineql+) for Ag

Total Ag

Ag+

AgCl(aq)

Total Ag = AgCl(aq) + Ag+

42

Plating of reduced silver onto copper pipes Ag0 dendrites

Cu pipe

Reaction Potential, V Implication

More Noble Ag+ + e-↔ Ag0 +0.799 (Cathodic)

More Active Cu+2 + 2e-↔ Cu0 +0.342 (Anodic)

• Implications on silver disinfecting ability for bulk water and for biofilms • Possibility of deposition corrosion for Cu pipe 43

Aesthetic problems

CSI

• Grey/purple staining consistently observed in bathroom porcelain throughout buildings A and B • XRD analysis identified precipitate as AgCl(s) • Caused temporary inactivation of CSI

Ag+ + Cl- ↔ AgCl(s) K=5.62 x 109 at 25 °C 44

Conclusions

• The cation exchange softener installed in Building A for hot water treatment countered the CSI treatment

•Negative reactions to the staining led the hospital to consider alternatives that would eliminate the staining

• Deposition of metallic silver onto copper pipes after CSI activation was verified for the first time

• Extracting and analyzing pipes hidden inside walls can proactively identify interactions not visible to the naked eye

• Although the primary aspect of CSI is the effect on controlling Legionella and other pathogens in water, non-microbiological implications deserve exploration to holistically evaluate in-building drinking water disinfection

45

Acknowledgments

• Dr. Marc Edwards, Dr. Yanna Lambrinidou, Dr. Daniel

Gallagher and Trung Le (Master’s student) at Virginia

Tech

• Dr. Darren Lytle, Christy Muhlen and Mike Elk at EPA

(hospital project)

• Michael Schock and Dr. Michael DeSantis at EPA

(corrosion studies)