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Arsenic is the 52nd most abundant element on the earth, averaging 2 parts per million (ppm) of the earth’s crust. Arsenic is classified as a metal by the periodic table of elements. Elemental arsenic is a steel-gray colored mineral with a metallic luster that tarnishes in air to a black oxide.  The free elemental form of arsenic is very rare. Arsenic is usually bound up in rocks with other minerals and leaches into water as arsenate (+5 oxidation state or pentavalent arsenic) or arsenite (+3 oxidation state or trivalent arsenic.) Arsenite is more difficult to remove from water because it has no charge in pH neutral water.

Both are known to be potent carcinogens in humans but arsenite or trivalent arsenic (the kind most likely to be found in unchlorinated private wells) it thought to be at least 60 times more toxic than pentavalent arsenic (the kind most likely to be found in chlorinated municipal water.)

Early civilizations in China, Greece and Egypt were familiar with arsenic-containing minerals that were mined along with co- existing native metal ores of lead, gold and copper.  The arsenic minerals were used as pigments: yellow (orpiment) and red (realgar).  The early Greeks identified metals with gender and called yellow orpiment “arsenikon” to associate it with “arenikos” meaning male.  Between 2,000 and 600 BC during the Bronze Age, the Greeks used arsenic compounds to harden copper-tin alloy implements. 

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Arsenic is widely distributed in drinking water throughout the world. In the United States, it is a problem contaminant in the vast majority of drinking water supples, both in municipal water as well as private wells.

The NRDC analyzed data compiled by the U.S. Environmental Protection Agency on arsenic in drinking water in 25 states. Their most conservative estimates based on the data indicate that more than 34 million Americans drink tap water supplied by systems containing average levels of arsenic that pose unacceptable cancer risks. 

It is likely that as many as 56 million people in those 25 states have been drinking water with arsenic at unsafe levels -- and that's just the 25 states that reported arsenic information to the EPA. 
 Health Effects of Arsenic in Drinking Water 
 According to a 1999 study by the National Academy of Sciences, arsenic in drinking water causes kidney, bladder, lung and skin cancer, and may cause prostate and liver cancer. It also appears to make certain cancers more aggressive. The study also found that arsenic harms the central and peripheral nervous systems, as well as heart and blood vessels, and causes serious skin problems. It also may cause birth defects and reproductive problems.

Arsenic is considered an “accumulative enabler” because it makes people more likely to become ill from various cancers, diabetes, and high blood pressure.  It may cause diseases related to the cardiovascular, pulmonary, immunological, neurological and endocrine systems within the body. 

The table below shows the lifetime risks of dying of cancer from arsenic in tap water, based on the National Academy of Sciences' 1999 risk estimates (see our report for details on how we calculated total cancer risk).
The table below shows the lifetime risks of dying of cancer from arsenic in tap water, based on the National Academy of Science


Arsenic Level in Tap Water (in parts per billion, or ppb)

Approximate Total Cancer Risk

(assuming 2 liters consumed/day)

0.5 ppb

1 in 10,000

1 ppb

1 in 5,000

3 ppb

1 in 1,667

4 ppb

1 in 1,250

5 ppb

1 in 1,000

10 ppb

1 in 500

20 ppb

1 in 250

25 ppb

1 in 200

50 ppb

1 in 100



The shocking thing is that EPA efforts to force municipalities to remove dangerous levels of arsenic from drinking water have been thwarted because of how much it costs to remove arsenic. 

The EPA limit was lowered from 50 parts per billion to 10 parts per billion, but that is for pentavalent arsenic. If you get your water from a well that contains trivalent arsenic, your water is 60 times as toxic as the above chart indicates.

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 What Can I Do To Avoid Arsenic? 
Arsenic is dangerous only when consumed. That means you don't have to treat water in which you bathe or shower. Your concern relates to water that is used for drinking and cooking.
Unfortunately, arsenic is one of those contaminants that you can't rely on municipal treatment or bottle water to eliminate because it is a contaminant that is very difficult, and very expensive to remove. Your best bet is to rely on a point-of-use (POU) water treatment system designed to do the job effectively and reliably.
Distillers do a good job on arsenic. The problem with distillers is that they require power to operate so if you lose power, you also lose your supply of safe water. Distillers also concentrate certain dangerous contaminants like chloramine in your drinking water.
Most reverse-osmosis (RO) systems can effectively reduce arsenic if they have good thin-film composite membranes and are operated with high enough water pressure. The problem with most RO systems is that they also concentrate chloramine in drinking water.
If you have a cartridge based water treatment system like certain LivingWaters systems, you can use a media called activated alumina that is specially designed to remove both fluoride and arsenic from water. The key is to make sure that the media has enough contact time with the water being treated. This means you will need one entire standard-sized cartridge (2-1/2" x 9-3/4") that is completely filled with the highest quality media, and make sure that the cartridge is processing no more than 3/4 of a gallon per minute. The LW10FRC is an example of this kind of cartridge. Just make sure you change it at least once per year or if your water usage is high, once every six months.

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 If you are on a well and there is iron present in your water, the hands-down best way to remove it is to install a chlorine feeder either on the well, or on an open air tank with a repressurization pump. Either of these kinds of units require a special multi-media backwashing tank after the chlorine treatment. Systems like the one illustrated above that use dry chlorine pellets are more reliable and require far less maintenance than the types that use chlorine bleach.

These systems are not cheap (the open-air tank and its associated multi-media backwashing tank) run about $5,000 installed, but they are a bargain when you consider that they are the most effective way to remove not only both forms of arsenic, but also iron, manganese, hydrogen sulfide, radon and methane gas, sulfate, tannins, iron and sulfur bacteria as well as pathogenic microbiological organisms, algae, mold, low pH and more. Best of all, they can perform the removal of these particularly difficult contaminants on low producing wells because they don't require extensive amounts of backwashing.

For more information on these systems, contact our engineering department by clicking here.

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LivingWaters™ Engineered Water Treatment Solutions
P. O. Box 7261
Woodland Park, Colorado 80863
Phone: 719-687-2928

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