Virus Study
By Anita Anderson and Lih-In Rezania, Minnesota Department of Health
Background
Beginning in May, the Minnesota
Department of Health (MDH) will
implement a study of viruses in
groundwater by conducting virus
monitoring on a set of representative public
water supply wells. This study was
requested by the Minnesota legislature and
is currently funded for two years through
the Clean Water Fund.
Waterborne viral illness outbreaks have
been associated with groundwater sources.
In addition, it is unknown whether these
viral contaminants are responsible for a
significant portion of endemic (nonoutbreak) illness, or if they are responsible
for outbreaks with no known cause.
National surveys have shown that
approximately 30 percent of drinking water
wells may be contaminated with human
pathogenic viruses. MDH would like to
determine if this national occurrence rate is
a good estimate of virus contamination in
Minnesota, or if the following factors might
lead to a different incidence rate in our
state:
•
•
•
the requirements of the Minnesota
Well Code
management practices for contaminant
sources
unique climatologic or geologic factors
Some of you may remember participating in
a virus study in the late 1990’s. The current
study will cover a wider range of well
characteristics and utilize improved virus
detection techniques that are now
available.
Year One
The first year of the study will involve bimonthly sampling at approximately 75
public water systems. These public water
systems were randomly selected from a list
that represents year-round, nondisinfecting, groundwater public water
systems in Minnesota. This sampling should
allow us to get the big picture of virus
occurrence in Minnesota and will help
determine what sources should be sampled
in the second year of the study.
If we discover that viruses are a problem in
Minnesota, we would like to be able to
predict which sources are most likely to be
subject to contamination. Viruses behave
differently from bacteria, so the coliform
bacteria sampling that is currently
conducted is often not a good indicator of
virus occurrence. Existing regulations do
not require continuous disinfection of all
public water supplies, but groundwater
supplies that are subject to contamination
need to provide treatment in order to
protect public health. Virus analysis is very
expensive, therefore we would like to be
able to use other tools to predict virus
occurrence. Additional data will be
collected on the wells being sampled in
order to refine MDH’s methodology for
identifying wells that are at risk to pathogen
contamination. The data will help by linking
the presence of viruses in a groundwater
source to factors such as well construction,
geologic sensitivity, and chemical and
biological water quality parameters.
Year Two
A parallel study starting in May of 2015 will
evaluate the association between source
water virus concentration and community
acute gastrointestinal illness incidence rate.
Community illness will be tracked in study
communities and related to the presence
and type of viruses in source water.
Summary
The work of this project will provide
information critical to determining if virus
contamination presents a human health risk
in Minnesota groundwater. The data
generated will be used to identify critical
factors that contribute to the protection of
drinking water sources and to reduce the
public health risk should pathogens be
present.
Fact Sheet at a Glance
Cross Connections and Water Softeners
http://www.health.state.mn.us/divs/eh/water/factsheet/ncom/croscon.pdf
Isolation Distances from a Water Supply Well
http://www.health.state.mn.us/divs/eh/wells/construction/isolate.pdf
Other fact sheets–
http://www.health.state.mn.us/divs/eh/water/factsheet/index.html
Update on the Revised Total Coliform Rule
By Paul Felling, Minnesota Department of Health
The primary purpose of the Revised Total Coliform Rule (RTCR) is to increase public health
protection by reducing potential pathways that could allow the entry of fecal contamination
into public water supplies. This new federal regulation goes into effect on April 1, 2016 and
applies to all public water systems. An introductory article to the RTCR was previously released
in the Fall/Winter 2013/2014 edition of The Noncom Scoop. Below is a summary of some key
potential transitions that lie ahead:
•
Some systems may experience an increased frequency of total coliform sampling since the
eligibility for an annual sampling schedule will be based on a system meeting specific criteria.
•
Investigations conducted in response to confirmed total coliform detections will focus on
identifying sanitary defects and getting them resolved.
•
Seasonal public water systems that depressurize their distribution systems will be required to
start up their water systems using an approved procedure.
•
Seasonal systems will have to certify to the Minnesota Department of Health (MDH) that the
start-up procedure was completed.
MDH is currently planning for the implementation of the RTCR. Over the upcoming months,
sanitarians will be asking water system owners and operators for information regarding their
system’s operating periods and whether or not portions of the system are depressurized. This
information will be used to update the public water inventory in regards to seasonal system
status. Sanitarians will also be working with owners and operators to develop a total coliform
sample site plan for each system. During their onsite visits, sanitarians may be asking questions
regarding the layout of distribution system(s) and the availability of water sampling taps. An
approved seasonal system start-up procedure draft has been developed by MDH and it has
been shared with several affected groups for comments. It is anticipated that the approved
start-up procedure will be finalized sometime this summer.
A preliminary list of sanitary defects has been discussed by MDH’s Noncommunity Unit.
Sanitary defects are assessed during investigations following total coliform detections and
during sanitary survey inspections. The federal regulation defines a sanitary defect as “a defect
that could provide a pathway of entry for microbial contamination into the distribution system
or that is indicative of a failure or imminent failure in a barrier that is already in place.” A
finalized list of sanitary defects will be completed by late 2014 or early 2015. Expect to see the
start-up procedure and the defect list in upcoming editions of The Noncom Scoop. If you have
additional questions or comments, please contact Jerry Smith (651-201-4657) or Paul Felling
(218-308-2107), from MDH. The Fall/Winter 2013/2014 edition of The Noncom Scoop can be
found at: http://www.health.state.mn.us/divs/eh/water/ncom/scoop/2013fall.pdf
The Noncom Scoop – Electronic Version
http://www.health.state.mn.us/divs/eh/water/ncom/scoop/index.html
Upcoming Training
Class D Small Public Water Systems
Date
Location
April 8, 2014
Bemidji – MDH District Office
April 22, 2014
North Branch
July 22, 2014
St. Bonifacius - Crown College
Class E Small Public Water Systems
May 13, 2014
Willmar
May 20, 2014
Little Falls
June 3, 2014
Rochester
If you have any
questions regarding
plan review, call
651-201-4700
All trainings are offered by Minnesota Rural Water Association
For more information on the courses and upcoming events visit http://www.mrwa.com/
The Noncom Scoop is published by the Noncommunity Public Water Supply Unit, Minnesota
Department of Health. Tell us what you want to read about in the Scoop! Contact:
[email protected]
The Noncom Scoop
Environmental Health Division
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