Arsenic is a semimetal, or metalloid, that is a member of the nitrogen family, and is recognized by the World Health Organization as the most significant chemical contaminant in drinking-water globally. As an element of the Periodic Table, it is designated by the symbol “As.” Arsenic occurs naturally and is the 20th most abundant trace element in the earth’s crust. It is odorless and tasteless.
It has been estimated that elevated levels of arsenic adversely impact over 200 million people worldwide and 44 million individuals in the United States. Of those in the USA, roughly 2 million are drinking from private wells that have high concentrations of arsenic. A recent survey by the U.S Geological Survey (USGS) found that arsenic exceeded 5 parts per billion (ppb), in 8% of the wells in Pennsylvania.
Sources of arsenic contamination can be natural or industrial. Naturally occurring deep subsurface brines containing arsenic can seep upwards into drinking water due to processes used in producing oil and natural gas. Consumption of food and water are the primary sources of exposure to arsenic for the majority of US citizens. People may also be exposed through industrial sources, as arsenic is used in semiconductor manufacturing, petroleum refining, wood preservatives, animal feed additives, and herbicides. Arsenic used to be utilized as a pesticide in orchards, therefore a primary concern for exposure through food would be juices, especially apples.
Arsenic can combine with other elements to form inorganic and organic chemical compounds called arsenicals. In general, inorganic forms are regarded as more toxic than the organic forms. While food contains both inorganic and organic arsenicals, water primarily contains only inorganic forms. Arsenic in groundwater is largely the result of minerals dissolving from weathered rocks and soils. It is often associated with methane gas, hydrogen sulfide gas, saline water, and anaerobic (low oxygen) conditions in a wellbore.
Depending on the level and duration of exposure, arsenic has been associated with the following health issues: stomach pain, nausea, vomiting, diarrhea, cancer, liver disease, diabetes, hypertension and cardiovascular problems, digestive difficulties, thickening and discoloration of the skin, cramping muscles, nervous system disorders, numbness in the hands and feet, partial paralysis, and blindness. A recent study has correlated low levels of arsenic exposure with heart damage after only 5 years of exposure.
On January 22, 2001, the EPA adopted a new standard for arsenic in drinking water of 10 parts per billion (ppb), replacing the old standard of 50 ppb. Public water systems had to comply with the new standard by January 23, 2006, to protect consumers from the effects of long-term, chronic exposure to arsenic. Based on a cancer risk of 1 in 1,000,000, Pennsylvania has a clean-up standard for a use aquifer that is 0.002 mg/L (2 ppb) and California has a maximum contaminant level goal of 0.004 mg/L (4 ppb). In certain states, such as New Jersey, the drinking water standard for Arsenic is as low as 0.005 mg/L (5 ppb).
Comprehensive water testing should be done to determine more than just the presence of arsenic. It is critical to know the form of arsenic present as some forms are more effectively removed than others, and knowledge of other water quality characteristics will influence the technology selected to treat the problem. Information should be gathered about your water supply source, well construction, surrounding land-use, and local geology. All of these factors should be considered in designing an effective treatment system.
Level 1 Testing is done with simple observations that an individual can make with their own senses such as sight, smell, and taste. These observations can be readily apparent or can be observed as they change over time. In addition, accessible related information about the home can also be used to narrow down the cause of your water issues.
Arsenic does not impart a noticeable taste, odor, or appearance to the water. Indicators that arsenic may be present in your water include:
Click on Map to See Full Scale - Arsenic concentrations in Ground Water of the United States. (Source USGS)
"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."
Level 2 Testing is Do-It-Yourself testing that can be done in your own home using a Testing Kit. After you’ve done Level 1 Testing, Level 2 Testing can confirm if your observations are correct. If your test results reveal the presence of a contaminant that is cause for concern, you can either proceed to determine the best treatment (see below) or continue to Level 3 Testing.
You might be concerned about arsenic in your drinking water if the general mapping information suggests you may have a problem, you are experiencing a problem with water that has an iron, manganese, or sulfur issue; your water is from a deep well; or you are located near a known hazard, such as an old apple orchard, civil war era cemetery, landfill, or commercial facility that uses arsenic, or you show symptoms associated with arsenic exposure.
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<div class="product-note in-L4-sulfur-treatment">Note: Use in combination with Sulfate-Reducing Bacteria Test</div>
<div class="product-note in-L6-bromate">Note: If the concentration is < 0.01 mg/L</div>
<div class="product-note in-L6-uranium">Note: Uranium less than < 0.030 mg/L</div>
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<div class="product-note in-L4-sulfur-treatment">Note: Use in combination with Sulfate-Reducing Bacteria Test</div>
<div class="product-note in-L6-bromate">Note: If the concentration is < 0.01 mg/L</div>
<div class="product-note in-L6-uranium">Note: Uranium less than < 0.030 mg/L</div>
Order a Neighborhood Environmental Report to learn about potential hazards in your community.
Level 3 Testing is done through an accredited Water Testing Laboratory. With Level 3 Testing, you can order a testing kit that is used to prepare your sample and submit it to the lab. By utilizing a lab, you have the assurance that a certified water expert had analyzed your water sample. If your test results reveal the presence of a contaminant that is cause for concern, you can either proceed to determine the best treatment options (see below) or continue to Level 4 Testing - Certified Testing.
For well owners and private water systems, we would recommend the Water Check Standard Testing Kit, but if you are located in an agricultural or industrial area we would recommend the Deluxe Testing Kit. For City Water customers, we would recommend the City Water Standard Testing Kit.
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<div class="product-note in-L4-sulfur-treatment">Note: Use in combination with Sulfate-Reducing Bacteria Test</div>
<div class="product-note in-L6-bromate">Note: If the concentration is < 0.01 mg/L</div>
<div class="product-note in-L6-uranium">Note: Uranium less than < 0.030 mg/L</div>
A Level 4 Certified Test Test uses chain-of-custody with a water professional coming to your home to prepare the water sample and then works with an accredited laboratory in order to certify your test results. This type of testing not only gives you the highest level of assurance in the accuracy of your test results, but can also be used as a document in legal cases. For Baseline Testing, we recommend that you use Certified Testing.
Specialized sampling and testing may be needed to determine the species and oxidation state of the arsenic. Arsenic may be present as Arsenic +3 (trivalent arsenic or arsenite) or Arsenic +5 (pentavalent arsenic or arsenate) and if you are experience odors, high standard-plate counts, high chlorine demand, and/or slime coatings, you may want to check for nuisance bacteria. If the arsenic is present as Arsenic +3, the treatment system will require an oxidation phase to convert the arsenic to Arsenic +5. During this process, organic compounds, sulfur, iron, manganese, humic substances, and other carbon sources may interfere with this oxidation.
Order a Neighborhood Environmental Report to learn about potential hazards in your community.
If you do have arsenic present in your water, there are treatment technologies available that can reduce or completely remove it. For them to work properly, in some cases a pretreatment system will also have to be installed. Some of the treatment technologies may not be practical to employ as point-of-entry or whole house treatment systems. In these cases, point-of-use units may be the best solution.
Regularly scheduled water testing should be done after the treatment system is in place to make sure it is operating properly and that the problem is being controlled. Most systems will require maintenance on at least an annual basis. As a safeguard against organic arsenic, it is necessary to conduct detailed testing on water collected at points along the pipeline before and after any installed treatment systems. It may be advisable to consider using a granular activated carbon filtration system to yield the best protection.
If your water has arsenic contamination, it is likely you will also have elevated levels of iron and/or manganese. If testing reveals this to be the case, a short-term solution could be to install a system for treatment of elevated iron and manganese. The processes used for treating these elements tend to decrease levels of arsenic as a side effect, usually to a level at which the remainder could then be removed by the installation of an economical point-of-use device which may include reverse osmosis (R/O or ion exchange (IE).
<div class="product-note in-L4-carbon-filtration">Note: For rural Areas with <a href="/indoor-6/herbicides-pesticides">Herbicides and Pesticides</a> Usage</div>
<div class="product-note in-L4-sulfur-treatment">Note: Use in combination with Sulfate-Reducing Bacteria Test</div>
<div class="product-note in-L6-bromate">Note: If the concentration is < 0.01 mg/L</div>
<div class="product-note in-L6-uranium">Note: Uranium less than < 0.030 mg/L</div>
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For the long-term, it may be necessary to install a more advanced water treatment system. The following technologies are effective for reducing arsenic in drinking water: activated alumina filters, anion exchange, distillation, reverse osmosis, nanofiltration, and iron oxide filters.
<div class="product-note in-L4-carbon-filtration">Note: For rural Areas with <a href="/indoor-6/herbicides-pesticides">Herbicides and Pesticides</a> Usage</div>
<div class="product-note in-L4-sulfur-treatment">Note: Use in combination with Sulfate-Reducing Bacteria Test</div>
<div class="product-note in-L6-bromate">Note: If the concentration is < 0.01 mg/L</div>
<div class="product-note in-L6-uranium">Note: Uranium less than < 0.030 mg/L</div>
