Arsenic In Drinking Water and Groundwater United States

arsenic, groundwater, toxic metals, arsenates, arsenic testing private wells
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Note:  The Shock Disinfection process may temporally increase the level of iron, manganese, aluminum, arsenic, and other constituents in your well water.  Therefore, it is recommend to properly and thoroughly test you well water following a shock disinfection.  This testing should not only include bacteria, but general water quality. 

For informational testing, we recommend the Well Check Package.  
Our Observation appears to be supported by the NGWA- Paper on Arsenic

What is arsenic?

Arsenic is a semi-metal, a member of the nitrogen family. It occurs naturally in the earth and in the seas. It is odorless and tasteless. Arsenic is an element (As) that occurs in the earth’s crust-rock, soil, all natural sources of exposure, or can be traced to deep water brines used to produce oil and natural gas.    Consumption of food and water are the major sources of arsenic exposure for the majority of US citizens.  People may also be exposed from industrial sources, as arsenic is used in semiconductor manufacturing, petroleum refining, wood preservatives, animal feed additives, and herbicides.

Arsenic can combine with other elements to form inorganic and organic arsenicals. In general, inorganic derivatives are regarded as more toxic than the organic forms. While food contains both inorganic and organic arsenicals, primarily inorganic forms are present in water. Exposure to arsenic at high levels poses serious health effects as it is a known human carcinogen. In addition, it has been reported to affect the vascular system in humans and has been associated with the development of diabetes. 

As compared to the Western part of the United States,  it is relatively rare  contaminant in Pennsylvania groundwater supplies.  A recent survey by the U.S Geological Survey (USGS) found that arsenic exceeded 5 ppb in 8% of wells in Pennsylvania.  Recent work in Northeastern Pennsylvania - Indicates that it that the occurrence may be slightly higher.

What is the measurement of arsenic?

On June 22, 2000 EPA proposed a 5 ppb standard for arsenic. EPA requested comment on 10 ppb, 5 ppb and 3 ppb.  Based on the comments, EPA is implementing a 10 ppb standard for arsenic.  This rule became effective on February 22, 2002 and systems  must comply with the new 10 ppb standard is January 23, 2006.   Arsenic in groundwater is largely the result of minerals dissolving from weathered rocks and soils. Several types of cancer have been linked to arsenic in water. In 2001 the US Environmental Protection Agency lowered the maximum level of arsenic permitted in drinking water from 50 micrograms per liter (ug/L) to 10 ug/L.  In certain states, such as: New Jersey, the drinking water standard for Arsenic is as low as 5 ug/L.

"The USGS has developed maps that show where and to what extent arsenic occurs in groundwater across the country. The current maps are based on samples from 31,350 wells. Widespread high concentrations were found in the West, the Midwest, parts of Texas, and the Northeast. See Ryker (2001) for more information. See Focazio and others (2000) for the use of available data for characterizing arsenic concentrations in public-water supply systems."

What are the symptoms of arsenic poisoning?

Observable symptoms of arsenic poisoning are: thickening and discoloration of the skin, stomach pain, nausea, vomiting, diarrhea, numbness in hands and feet, partial paralysis, and blindness.

How does arsenic enter my private water system?

It is widely thought that naturally occurring arsenic dissolves out of certain rock formations when ground water levels drop significantly. Surface arsenic-related pollutants enter the ground water system by gradually moving with the flow of ground water from rains, melting of snow, etc. Either way, ongoing testing for arsenic is an important strategy by the private water system owner to safeguard the health and well being of their family.

Is my private well at risk?

Like many contaminants in drinking water, the element is potentially hazardous at levels or concentrations that do not impart a noticeable taste, odor, or appearance to the water.  Your best course of action is to get you water tested and compile as much information as possible about your water supply source, well construction, surrounding land-use, and local geology. If you do have an arsenic problem, there are water treatment technologies available now that can reduce or even remove arsenic from your drinking water.  Note: Do not just test your water for Arsenic because there may be other primary and secondary drinking water standards that are elevated or that may interfere with the proposed remediation system.

Drilling Management Approaches

1. Over-pumping of the aquifer may contribute to this problem.  The primary suggestions:
a. The space between the casing and borehole wall should be at least 1 inch.  Therefore- if you are installing a 6-inch well, you need to drill an 8- inch borehole so the space between the casing and borehole wall can be grouted.
b. pH of the grout should be between 7 and 8.5 and the slurry density should be over 15.2 lbs per gallon (over 15.6 lbs per gallon better).
c. After grouting, the well should set undisturbed for 24 hours.
d. Use liquid chlorine at a level of less than 100 mg/L to shock disinfect borehole.
e. Use a rotary washing method rather an air-rotary for the lower portion of the wellbore.
f. Use a Braden-head pressure grouting technique. More on Grouting
g. Use air lift - keep drill string about 60 feet from the bottom of the casing and rate should be less than 700 cubic feet per minute.

Actions: Learn - Get it Tested)

1. Get your Water Tested and encourage your neighbors to do the same.
2. Compile information on the types and location of hazardous waste and industrial sites in your area.
3. Contact your States Environmental Protection Division.
4. Private Well Arsenic Screen
5. Mail Order Water Testing Kit 
6. Water Testing Screening by the Well Driller or Water Professional 


What types of treatment devices will make my water safe for consumption?

The following water treatment technologies are effective in reducing arsenic from drinking water:

1.Activated alumina filters
2.Anion exchange
4.Reverse Osmosis
6. Iron Oxide Filters

Action: Act - Get the Water Treated

Arsenic Treatment systems and other treatment systems

Pretreatment may be needed in some cases to ensure acceptable treatment by the primary unit. Also, as a safeguard against organic arsenic, granular activated carbon filtration should be added. Some of the treatment technologies may not be amenable to point-of-entry, whole house treatments. In these cases, point-of-use units may be the best option. Periodic testing should be maintained after the treatment system is in place to ensure objectives are being met.

Note: In many cases, arsenic will be removed when iron is removed through an oxidation process. Recent Testing in Northeast Pennsylvania (NEPA) - Available Data shows 8% of the Private Wells had Arsenic Above the Primary Drinking Water Standard. 

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Arsenic in Private Wells Pennsylvania
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PA DEP Portal on Arsenic in Drinking Water

EPA On Arsenic
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Arsenic in New Jersey



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