Arsenic Fact Sheet - Nimbus Water Systems WaterMaker Five WM5-50 User Manual

Arsenic Fact Sheet

Arsenic (AS) is a natually occuring 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 US Environmental Protection Agency website: www.epa.gov/safewater/arse-
nic.html.
There are two forms of arsenic: pentavalent arsenic (also called AS(V), As , and arsenate) and trivalent arsenic (also called
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AS(III), As , and arsenite). In well water, arsenic may be pentavalent, trivalent, or a combination of both. Special sampling
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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.
Reverse osmosis (RO) water treatment systems are very effective at removing pentavalent arsenic. RO systems do not
remove trivalent arsenic from water very well. 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 WM5-50 system is designed to remove pentavalent arsenic. It will not convert trivalent arsenic to pentavalent arsenic.
The system was tested in a lab. Under those conditions, the system reduced 50 ppb pentavalent arsenic to 10 ppb (the
USEPA standard for drinking water) or less. The performance of the system may be different at your installation. Have the
water tested for arsenic to check if the system is working properly.
The RO component of the WM5-50 system must be replaced yearly to ensure the system will continue to remove pentava-
lent arsenic. The component identification and location where you can purchase the component are listed in the installa-
tion/operation manual.
42445 Avenida Alvarado, Temecula, CA 92590
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(800) 451-9343 · www.nimbuswater.com