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Get Informed | What is Selenium?

Selenium is a naturally occurring metalloid, i.e., has properties that are between metals and nonmetals has a metallic luster, and can appear gray to grayish-black, reddish-gray or red. Selenium is typically associated with sulfur-containing minerals and can be found in areas that have selenium minerals in sedimentary rocks, such as some carbonates and coal beds, and volcanic (igneous) rocks. Selenium is an essential trace mineral that is critical for human health. This trace nutrient plays a role in the reproductive, cognitive, and immune system for humans. The primary source of selenium intake is through food.

Selenium is used in the production of glass, pigments, photovoltaic cells, energy-efficient windows, semiconductors, rubber, steel alloys, and electronic devices and is a by-product of copper mining, smelting and coal ash storage.

How Does Selenium Become a problem?

Selenium toxicity because of overexposure is rare, especially from dietary sources, but an overdose of highly concentrated supplements could have negative effects. Selenium deficiency can result in arteriosclerosis, i.e., the arteries narrow. Selenium exposure may be related to your consumer products you purchase and make-up/cosmetics you use.

What are the Health Risks for Selenium?

Elevated levels of selenium have been associated with hair and fingernail loss, nervous system damage, fatigue, irritability, numbness in fingers and toes, circulatory disorders, kidney failure, liver damage, and, in extreme cases, death.  High levels of selenium exposure have been associated with brittle hair and hair loss and brittle broken finger nails, which is a condition known as selenosis.

(Book: Amazon "Death in the Marsh).

What are the Standards for Selenium?

The EPA MCL for selenium is 0.05 mg/L or 50 ppb. This is a primary drinking water standard that has been set for public health reasons.  Hong Kong and the World Health Organization set a standard of 0.04 mg/L and 0.01 mg/L, respectively. View the USGS map on Selenium by county.

Get Tested | Selenium

Like many contaminants in drinking water, this 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 your water tested and compile as much information as possible about your water supply source, well construction, surrounding land-use, and local geology. Selenium occurs as Selenium (VI) (oxidized form) and Selenium (IV) (reduced form). The oxidized form of selenium is more common. The effectiveness of some methods for removing selenium from water depends on its chemical form. If you do have a selenium problem there are water treatment technologies available now that can reduce or even remove selenium from your drinking water.

Note - Do not just test your water for Selenium because there may be other primary and secondary drinking water standards that are elevated or that may interfere with the proposed remediation system.

Level 1 | Observational Self-Testing

Observations for Selenium

The symptoms/sources for selenium in the water include:

  • Your are located in an area where the USGS has identified the region as having elevated levels of selenium or in areas with volcanic activity (48 states, Alaska, and Hawaii)
  • You are located near a mining area or an industrial user of selenium or where selenium is generated as a by-product in the waste stream, such as in coal ash.
  • You are located near a landfill or other waste disposal site.
  • You have a garlic odor in your breath, and a metallic taste in your mouth, brittle hair, hair loss, and brittle or broken finger nails. There may also be gastrointestinal problems, joint pain, skin discoloration, and tooth loss (Symptoms of Selenosis).
Try Our Level 1 Drinking Water Self-Diagnostic Tool
Have water issues? Answer our self-diagnosis questionnaire from your observations to get an initial diagnosis. Then follow our recommended steps to remediate your issue.
Self-Diagnostic Tool
Neighborhood Environmental Report

Order a Neighborhood Environmental Report to learn about potential hazards in your community.

Level 2 | Do-It-Yourself Water Testing

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.

Notes on Level 2 Testing for Selenium

We are not aware of an in-home screening test for selenium, but we would recommend a basic in-home water screening test and you may want to consider conducting a hair analysis.  If you want to learn more about the role of selenium in human health and our food, we provide a link in the Recommended Reading selections below for your convenience.

Recommended Level 2 Tests
Water Check Deluxe

<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>

Filter Water
FW-210 Under-Sink Reverse Osmosis System (Code A27AC)

<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>


Level 3 | Informational Water Testing

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.

Notes on Level 3 Testing for Selenium

If you are on a private well or water source we would recommend the National Testing Labs WaterCheck Deluxe.  If you are on a regulated water source or city water, we would recommend the City WaterCheck Deluxe.   If you are considering a Reverse Osmosis unit, we recommend the National Testing Labs Special Testing for R/O applications.

Level 4 | Certified Water Testing

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.

Notes on Level 4 Testing for Selenium

Typically when considering testing for selenium, it is best to understand the potential sources of the selenium and we strongly suggest conducting an informational test to identify other parameters of concern.

Get Treatment | Selenium

Pretreatment may be needed in some cases to ensure acceptable treatment by the primary unit. Some of the treatment technologies may not be amenable to point-of-entry or 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 and the system is operating properly. Most systems will require maintenance on at least an annual basis. Chemically, selenium occurs in water in two forms. Selenium (VI), the oxidized form of selenium, is the dominant form of selenium under oxidizing conditions, and selenium (IV) is dominant under reducing conditions. The effectiveness of some methods of removing selenium from water depends on its chemical form.

Short Term Treatments

If it appears you are experiencing a problem with selenium, do not boil your drinking water. An interim solution may be the use of a point-of-use device or using a bottled water source. Because other contaminants may be present in the water, it would be advisable to have the water tested before and after the use of any point-of-use device.

Contact a KnowYourH2O Recommended Professional

Submit a Request for Consultation with the KnowYourH20 Team. Contact Us

Long Term Treatments

For the long-term, it may be necessary to install a water treatment system. For selenium, the common water treatment technologies are ion-exchange, reverse osmosis, activated alumina filtration, and distillation. Depending on the technology and the concentration of selenium and other contaminants, the system may require a number of treatment approaches and a combination of a whole-house treatment and then point-of-use treatment.  It is unlikely that selenium is the only problem with the drinking water and it is likely you would need to install a pretreatment system prior to installing a R/O unit, such as the DIY Project: Filter Water: Eagle 4000A Whole House Filter and Water Conditioner (Code A27AC).  At a minimum, we recommend that you make sure you have completed the National Testing Labs Special Testing for Designing Reverse Osmosis Systems or the equivalent.

Contact a KnowYourH2O Recommended Professional

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