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Anita C. Anderson

NEHA Annual Educational ConferenceJuly 15, 2015

Acknowledgments

Clean Water Council – Clean Water FundMDH Drinking Water Protection Section: manager, supervisors, staff MDH Public Health Lab Laboratory for Infection Disease and Environment (USDA-USGS Lab) DWP district engineers and field sanitarians USGS Minnesota Water Science CenterUSDA-ARS - Dr. Mark Borchardt

MDH Study Team: IDEPC -Trisha Robinson, Amber Koskey DWP - Anita Anderson, Lih-in Rezania, Jim Walsh Dane Huber, Jared Schmaedeke, Trisha Sisto

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Clean Water, Land and Legacy

Amendment 2008

• 3/8% sale tax increase • Clean Water Fund: 33%

• Drinking Water: >5% CWF

Overview

�Background of the study

�Study design and objectives

�Phase I virus monitoring

�Phase II virus monitoring & community illness (Epi) study

�Preliminary findings

�Questions

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Why viruses?

�Waterborne viral illness outbreaks have been associated with groundwater sources

�National surveys have shown that approximately 30 percent of drinking water wells may be contaminated with human pathogenic viruses (AWWARF study).

Why viruses?

� It is unknown whether these viral contaminants are responsible for a significant portion of endemic (non-outbreak) illness, or if they are responsible for outbreaks with no known cause

�Viruses are not monitored routinely and behave differently than bacterial indicators

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Why viruses?

Bacteria Viruses

Size Small (1000nm)

Smaller (20 -400nm)

Electrical Charge

Varies across cell

Negative

Maximum Lifetime in Groundwater

About 1 year Up to 3 years

ObjectivesCWF Purpose To develop and implement a groundwater virus monitoring plan, including an epidemiological study to determine the association between groundwater virus concentration and community illness rates.

MDH PurposeTo build on previous efforts aimed at determining the public health risk due to virus contamination of drinking water, and to formulate strategies and refine existing tools to reduce the risk.

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A Phased Monitoring Approach� Phase I- Virus Occurrence Assessment

�One year, bi-monthly monitoring

�Non-disinfecting , year-round, CWS and NTNCWS

�82 Public Water Supply Wells “randomly" selected

� Phase II- Targeted Microbial Risks & Groundwater Assessment Monitoring Scoring Tool Evaluations

� Human Enteric Viruses and a Suite of Indicators

� Two main questions:

� Are there viruses in our groundwater?

� Are the viruses making people sick?

� Monitoring 6 water supplies weekly for viruses

� Enrolling community members to submit weekly health surveys

� May 1, 2015 – April 30, 2016

Minnesota Water and Virus Evaluation Study

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Groundwater Assessment

Monitoring Scoring ToolWell Scoring Criteria

� Geologic Sensitivity

� Saturated Casing Value

� Age Dating

� Nitrate > 1 ppm in 5 Yrs.

� Inner Wellhead Management Zone (IWMZ) Pathogen Source

� Confirmed Coliform in 5 Yrs.

� Surface Water Characteristics

Groundwater Category

A Rapid Recharge

B

Fecal Waste Impacted – B1

Mineral Fertilizer Impacted – B2

Road Salt/Water Softener

Impacted – B3

Post 1953-Impacted Non-pathogen – B4

CPost – 1953

Un-impacted

D

Pre – 1953

Impacted Non-Pathogen - D1

Pre -1953 Vintage - D2

E Saline

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Site Selection (Phase 1)� Year-round PWSs

� Non-disinfecting

� 567 PWSs

� 243 CPWSs

� 324 NTNCPWSs

� Random selection

� 82 PWSs/Wells

� 14.5% candidate PWSs

Indicators/Water Quality� TC/E. coli (MPN-QT)

� Enterococci (MPN-QT)

� Ammonia

� Chloride

� Bromide

� Nitrate (NO2 + NO3)

� TOC

� Boron

� Tritium (3H)

� Stable isotopes: 18O & 2H

� Temp

� pH

� Conductivity

� D.O.

� ORP

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Virus Sampling and Analysis� Laboratory for Infection Disease and

Environment (LIDE) � qPCR with a small subset of cell culture � Some DNA sequencing in Epi-Study� Human Enteric Viruses

� Adenovirus Group A� Adenovirus Group B � Adenovirus Groups C, D, and F� Enterovirus� Norovirus GI & GII� Hepatitis A� Human Polyomavirus� Rotavirus

� Pepper Mild Mottle Virus

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Backflush

Ultrafilter Freezer bottle

2° Concentration XNA Extraction

Inhibition

RT-PCR qPCR

1 mL aliquots cDNA

Minnesota Department of Health Study Work Flow

Data

XNA

Virus Monitoring Results42 Wells have had at least one detection (51%)

399 samples analyzed, 13.3% (53) with viral detection(s)

1920

2 3

9

23.224.4

2.53.9

11.7

0

5

10

15

20

25

30

May/Jun Jul/Aug Sep/Oct Nov/Dec Jan/Feb

# Positive Samples

% positive

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Virus Detect frequencies for rounds 1 - 5

Virus type Round 1 Round 2 Round 3 Round 4 Round 5

Adenovirus group A 0 0 0 0 0

Adenovirus group B 0 0 0 0 0

Adenovirus groups C, D, F 11 5 0 0 3

Enterovirus 4 1 0 0 2

GI Norovirus 0 0 0 0 0

GII Norovirus 0 0 0 2 2

Hepatitis A Virus 0 0 0 0 0

Human Polyomavirus 2 5 0 0 0

Pepper Mild Mottle 4 13 2 0 5

Rotavirus A 1 2 0 1 0

Total Positive Samples 19 20 2 3 9

# of Positive samples

aThis number is less than the sum of virus types because some

samples were positive for two or more viruses.

42 wells have had at least one detection (51.2%),32 wells (39%) have had at least one detection of human enteric viruses

Enterococci Detects: 0 TC/E. Coli. Detects: 15 (3.1%)

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First 5 Rounds of Microbial

Monitoring Results

2120

31

27

22

10

5

0

5

10

15

20

25

30

Viral/Bacteria (48) Viral (42) Bacteria (13) Viral + Bacteria (6)

Community PWS (37)

NTNC PWS (45)

Groundwater Characterization vs.

Microbial DetectionsGroundwater

Characterization

# of Wells

in Study

# of Wells

Any Detect

Micros Detect

(% of wells

with detects)

A 5 2 40%

B 32 14 44%

C 13 5 38%

D 32 13 41%

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Phase I Monitoring Findings� A sound study approach to evaluate virus

occurrence

� Similar occurrences between the Community and the Non-Community Wells

� 13.3% of samples with viral detection(s)

� Estimating a 40+% occurrence rate for the enteric viruses

� Wells previously thought not vulnerable appear to be susceptible to virus

� Results seem tied to recharge events

Possible Reasons for High

Occurrence Rates

� Extreme weather: heavy snowpack in April, wettest June in MN history

� Frequent sampling: bi-monthly, includes winter months

� Techniques:

� High volume, 300 - 800 liters; average 750 L/sample

� Dead-end UF filters

� Improved lab techniques - qPCR

� Covered more viruses than many other studies

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Possible High Speed Low Volume Pathways

Need to change our thought process?

� Random selection with high occurrence rate was unexpected

� Improved testing techniques mean we will continue to find more contaminants

� Wells we thought not vulnerable appear to be susceptible to virus:

� Well construction

� Low volume, fast pathways

� Land use/sources of contamination

� Travel/survival different than bacteria

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� Traditional indicators not predictive

� Requires a suite of water quality and environmental parameters

� Health Risk

� Are the viruses making people sick?

� What is risk relative to other exposures?

Need to change our thought process?

Anita Andersonanita.c.anderson@state.mn.us218-302-6143