US Geological Survey Arsenic Map
What is the significance of the USGS map?
The U.S. Geological Survey map above provides a national
snapshot of arsenic concentrations in the Nation’s
groundwater. The map is based on 31,350 groundwater samples
and shows
arsenic concentrations found in at least 25% of samples
per county. What is the source of arsenic?
Arsenic is a naturally occurring element in the environment.
Its presence in groundwater largely is the result of arsenic-bearing
minerals dissolving naturally over time as certain types
of rocks and soils are weathered.
What are the human health concerns?
The public’s greatest exposure to arsenic is via drinking
water. Long-term exposure to arsenic via drinking water causes
cancer of the skin, lungs, urinary bladder, and kidney, and
causes serious skin problems. In addition, arsenic has been
reported to affect the central and peripheral nervous systems, as well as heart
and blood vessels. It has been associated with the development
of diabetes, and it also may cause birth defects and reproductive
problems.
How many Americans are exposed to arsenic in drinking water?
The National Resources Defense Council (NRDC) analyzed data
compiled by the USEPA on arsenic and estimates that 34 million
to as many as 56 million people drink tap water containing
average levels of arsenic that pose unacceptable cancer risks.
What are the consequences of the level of arsenic in my drinking
water?
According to National Academy of Sciences estimates, one out
of 100 people who drinking water containing 50 parts per billion
(50 ppb) will get cancer (based on drinking two liters of water
per day over the course of a lifetime). The lifetime risk of
dying of cancer from arsenic in tap water at la level of 10 ppb is
one in 500.
How can I find out whether my drinking water
contains arsenic?
First, contact your local water utility --it is required by
law to provide a report on all regulated (only) contaminants
and toxins found in your local drinking water. If you have
a private well, your public health departments may help in
locating laboratories to have your water tested. In addition,
the USGS District Office in your State might have information
from ongoing or previous arsenic investigations.
What is the regulated concentration of arsenic?
The current EPA standard for arsenic is 50 ppb. The new EPA
standard of 10 ppb will go into effect in 2006.
Where can I get more information about arsenic in ground water?
Additional information is available online at:
U.S. Environmental Protection Agency (USEPA)
U.S. Geology Survey (USGS)
World Health Organization (WHO)
Natural Resources Defense Council
What are the types of arsenic?
Inorganic arsenic can occur in the environment in several forms
but in drinking water it is mostly found as Arsenic III (trivalent
arsenite) or Arsenic V (pentavalent arsenate). Arsenic III
will convert to Arsenic V in water that is oxidized. Water
treatment chemicals or processes such as chlorine (when there
is a free chlorine residual), potassium permanganate, and
ozone will change trivalent arsenic to pentavalent arsenic.
A combined chlorine residual (i.e. chloramine) may not convert
all the Arsenic III. It may be advisable to contact your
public water utility to find out if free chlorine, or some
other oxidizer, is used in your water system.
Will Multi-Pure® Drinking Water Systems remove arsenic?
The Multi-Pure® MP 880
series has been tested and certified
to effectively remove pentavalent arsenic (Arsenic V). The
MP 880 may remove some trivalent arsenic; however, a standard
has not been established for Arsenic III. If Arsenic III
has been converted to Arsenic V, then the Multi-Pure®
MP 880 systems will remove it as Arsenic V.
Facts About Arsenic
Arsenic (abbreviated As) is a naturally occurring
contaminant found in many ground waters. Arsenic in water
has no color,
taste or odor. It must be measured by a lab test. Public
water utilities must have their water tested for arsenic.
You can get the results from your water utility. If you have
your own well, you can have the water tested. The local health
department or the state environmental health agency can provide
a list of certified labs. The cost is typically $15 to $30.
Information about arsenic in water can be found on the Internet
at the U.S. Environmental Protection Agency website: www.epa.gov/safewater/arsenic.html.
There are two forms of arsenic: pentavalent arsenic (also
called As(V), As(+5), and arsenate) and trivalent arsenic
(also called As(III), As(+3), and arsenite). In well water,
arsenic may be pentavalent, trivalent, or a combination of
both. Special sampling procedures are needed for a lab to
determine what type and how much of each type of arsenic
is in the water. Check with the labs in your area to see
if they can provide this type of service.
Specially formulated Carbon Block systems are very effective
at removing pentavalent arsenic. A free chlorine residual
will rapidly convert trivalent arsenic to pentavalent arsenic.
Other water treatment chemicals such as ozone and potassium
permanganate will also change trivalent arsenic to pentavalent
arsenic. A combined chlorine residual (also called chloramine)
may not convert all the trivalent arsenic. If you get your
water from a public water utility, contact the utility to
find out if free chlorine or combined chlorine is used in
the water system.
The Multi-Pure®
MP 880 Models are designed to
remove only pentavalent arsenic. It will not convert trivalent
arsenic
to pentavalent arsenic. The system may remove some trivalent
arsenic, however, it has not been evaluated for its ability
to remove trivalent arsenic. The system was tested in a laboratory
to remove pentavalent arsenic. Under lab conditions, as defined
in ANSI/NSF Standard 53, the system reduced 0.050 mg/L (ppm)
pentavalent arsenic to 0.010 mg/L (ppm) (the U.S. EPA standard
for drinking water) or less. The performance of the system
may be different at your installation. Have the treated water
tested for arsenic to check if the system is working properly.
The Carbon
Block filter component of the Multi-Pure®
MP 880 system must be replaced as indicated in the
Owner's Manual to ensure the system will continue to remove
arsenic and
other contaminants. The component identification and locations
where you can purchase the component are listed in the installation/operation
manual.
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