Environmental Health Water Testing
FREQUENTLY ASKED QUESTIONS
What is the issue?
An internal review by the Minnesota Department of Health (MDH) found inconsistent
procedures related to the handling of some drinking water samples. While current federal
guidelines call for certain samples to be kept at 4 degrees Celsius (about 40 degrees
Fahrenheit), there were some cases in which samples that should have been kept cool were
transported to the MDH Public Health Laboratory at room temperature.
How big a concern is this for public health and safety?
MDH believes it is unlikely that these inconsistencies resulted in a significant risk to the public.
In most cases, the data were unlikely to have been off by a large margin, but the inconsistent
practices introduced an unacceptable level of uncertainty to the data.
How did you find out about this problem?
MDH found these inconsistent procedures through an internal review.
What types of samples are affected?
The samples potentially affected are those for which temperature control is needed to prevent
degradation of the substance for which we are testing. These include certain organic chemicals
and inorganic compounds.
▪
▪
Organic chemicals in this category include fertilizers, solvents, pesticides and common
household chemicals. Some are naturally occurring, but those regulated by the federal Safe
Drinking Water Act are usually the result of human activities. They are often associated
with contaminated plumes from leaking landfills and underground storage tanks.
Inorganic compounds affected include nitrite (a substance related to but not identical to
nitrate) and cyanide.
While these compounds can cause concern at certain levels due to toxicity and persistent
tendencies in the environment, the actual risk to humans depends on the characteristics of the
specific compound and its level in the water. This situation does not impact samples taken to
analyze for the presence of viruses, fluoride, radionuclides, arsenic, lead, mercury or other
heavy metals.
ENVIRONMENTAL HEALTH WATER TESTING - FREQUENTLY ASKED QUESTIONS
Have we seen any suspicious patterns of illness that might be linked to
exposures to these substances at high levels?
Any additional risks to human health are likely to be quite low, well below the safety thresholds
built into the regulatory standards. We would not expect to see visible increases in any disease
rates that could not be attributed to other known risk factors.
How long has this inadequate process been in place?
The review that brought this issue to light indicates these inconsistent practices may have been
in place since the early 1990s.
What public water systems are most affected by this?
MDH will look first at samples from water systems that could be more affected by any
variations in the testing results. These include systems that draw water from sources
considered vulnerable to contamination from compounds as well as those that have shown
levels of results that have been near the maximum limit allowed.
In addition, water systems that disinfect their water will be looked at for disinfection
byproducts that may pose health risks under certain conditions.
What alternative sources of information exist about the systems?
Water sampling programs maintained by other state agencies can help provide reliable
information about some of the substances and drinking water systems in focus. These data
appear to indicate the risk to Minnesotans is limited.
What are you doing about this?
The MDH response plan for this issue includes the following elements:
▪
▪
▪
▪
Immediate communication and training for staff to ensure all water samples are kept at
proper temperature during transport from collection site to laboratory;
Evaluation of past monitoring results to determine which results complied with the
temperature requirements;
Prioritized review of water systems based on factors including past monitoring results; and
A broad, independent review of water sample handling procedures and practices of the
department.
How long will that response take?
The re-sampling of water systems with the greatest potential to have been affected by the
improper transport of earlier samples should be completed by this summer.
2
ENVIRONMENTAL HEALTH WATER TESTING - FREQUENTLY ASKED QUESTIONS
What kind of notification are you doing for affected communities?
MDH is notifying all affected public water systems in the state through existing channels we use
to share information with them. We will have additional outreach in the weeks ahead as
warranted.
What will MDH do if an issue is identified as a result of re-sampling?
MDH is committed to working with public water systems if re-sampling identifies an issue.
What protective recommendations do you have for people?
Although additional risks to human health are likely to be quite low, we understand some
people may wish to take additional protective actions such as purchasing in-home treatment
that is effective in removing organic chemicals and other substances.
What home water treatment units remove these substances?
Reverse-osmosis units are the most effective, although they are costly. Activated carbon filters
are also effective, and less costly. Regardless of the type of unit used, home treatment devices
must be regularly maintained according to the manufacturer’s instructions. Failure to properly
maintain a unit will reduce its effectiveness and, in some cases, may make the water quality
worse.
More information on home treatment units: Home Water Treatment Units: Point-of-Use
Devices (http://www.health.state.mn.us/divs/eh/water/factsheet/com/pou.html)
Where can we get more information?
More information call the Minnesota Department of Health Section of Drinking Water Protection at
651-201-4700 during normal business hours.
Drinking Water Protection
PO Box 64975
St. Paul, MN 55164-0975
651-201-4700
www.health.state.mn.us/water
02/11/2016
3