VOCs (volatile organic compounds) are EPA-regulated contaminants present in the air you breathe and the water you drink. They originate from a host of everyday products, from bug sprays to paint thinners to gasoline. Through improper industrial practices, spills, and runoff, VOCs can pollute the air and water supplies. While regulations are in place to control the number of VOCs in air and water, the presence of these compounds in water is enough to warrant concern. In this article, you can learn what VOCs are, how to test your water for them, and how to remove them from your water supply.
What are VOCs?
VOCs, short for “volatile organic compounds,” are organic chemicals with very low boiling points due to their high vapor pressure. Because of this characteristic, they can convert to a gaseous state when exposed to normal air temperature, an attribute known as volatility. In fact, many VOCs can convert to vapor in temperatures well below freezing. The main concern with VOCs is their presence in the air and in drinking water, leading to regulatory action by the EPA. The EPA’s emission standards continue to be updated to reduce the number and amount of VOCs present in the air and water supplies.
Where do VOCs come from?
VOCs are common in the atmosphere because they are present in many regularly used household products. Some of these include paint, gasoline, solvents, inks, glues, magic markers, and dry erase pens. The distinct odor when you take the cap off a permanent marker is an example of a VOC in action. That smell is a volatile organic compound releasing into a vaporous form after exposure to room temperature air. VOCs can also come from spray adhesives, pesticides, upholstery, caulking agents, cleaning products, and air fresheners.
What products contain VOCs?
VOCs can be found in a wide array of everyday products within and outside the home. Some of the most common sources of VOCs according to the EPA include the following:
- Aerosol sprays
- Dry-cleaned clothing
- Pesticides
- Air fresheners
- Wood preservatives
- Adhesives
- Permanent markers
- Disinfectants
- Wood preservatives
- Fuels
- Printers
- Building materials
- Furniture
How do VOCs get in water?
Most VOCs enter the water supply directly from improper disposal of these compounds, allowing them to leach into the ground. Once they have infiltrated the groundwater, VOCs can migrate from aquifers to lakes and reservoirs. Precipitation can further carry them to water supplies like wells and municipal plants. Some VOCs are created are the result of chemical reactions that take place during water disinfection processes, but these waterborne VOCs are a bit different than their airborne counterparts. Waterborne VOCs do not have the distinct taste or smell associated with many airborne VOCs like gasoline. If your water has a high level of volatile organic compounds, it is most likely one of the below types of VOCs.
Common examples of VOCs
Some of the most common VOCs found in water include trihalomethane, benzene, PCE, and MTBE.
Trihalomethane
Trihalomethane is the most common VOC found in water. It is a byproduct of water disinfection when chlorine is used to sterilize water by water treatment plants. When a water supply with organic content is chlorinated, the organics and the chlorine combine and create trihalomethane as a byproduct. This primarily happens when city suppliers chlorinate water from lakes or rivers. Because of how widespread this disinfection method is, trihalomethane is the most common waterborne VOC. The same trihalomethane compound is created when a private well owner puts chlorine in their well.
Benzene
Benzene is a colorless, flammable liquid found in gasoline and petroleum. When present in high concentrations in water, benzene gives the water a sweet odor, but it does not change the water’s appearance. While it is naturally occurring in gasoline, benzene is also used in industrial applications, such as the production of plastics, rubbers, detergents, and synthetic fibers. Both the EPA and the International Agency for Research on Cancer have determined that the compound is carcinogenic to humans.
PCE (Perchloroethylene)
PCE is a byproduct of solvents. PCE is commonly used in dry cleaning and as a degreaser at industrial sites. It is also found in consumer products like shoe polish and solvents used for diluting and breaking down inks.
MTBE (Methyl tert-butyl ether)
MTBE is a fuel additive. After lead was no longer legally allowed to be used with gasoline, MTBE was substituted to raise the octane number of the gas. After its usage became extensive, MTBE began to appear in water. From spillages to underground storage tank leakage, MTBE has caused swathes of groundwater and soil to become contaminated.
What is vinyl chloride?
Vinyl chloride is flammable, colorless VOC that is an essential component in the production of PVC. It is commercially manufactured and does not occur naturally. However, vinyl chloride is released into the environment through industrial production and discharge, storage and transportation accidents, workplace exposure, or improper disposal methods. This VOC is a particular cause of concern for the public because of its known carcinogenic risks. Vinyl chloride has been linked to liver, brain and lung cancers, as well as lymphoma and leukemia. The International Agency for Research on Cancer classifies vinyl chloride as a Group 1 carcinogen, the highest classification that denotes there is thorough and convincing evidence showing the agent causes cancer in humans.
Where are VOCs most common?
High levels of VOCs are more apt to be found in groundwater well supplies than they are in city water. However, city water can also have VOC levels, though you will not see them in high abundance. The EPA regulates 23 volatile organic compounds, meaning city water suppliers are required to monitor the levels of each compound. If the VOC content of water treated by a city water supplier ever rises above a maximum contaminant level set by the EPA, then the plant must take action to reduce the levels below the maximum contaminant level. Nonetheless, it is important to regularly test your groundwater to make sure your VOC levels are not too high, especially if you are a private well owner or if you have reason to believe your primary water source has been contaminated.
Are VOCs dangerous?
Determining the dangers of waterborne VOCs is difficult because of the variety of VOCs, but there is sufficient proof that high levels of VOCs have been linked to cancer in animals. Furthermore, there has not been extensive testing done to determine the health risks to humans posed by many of the household products that release VOCs. However, there is evidence exposure to VOCs has negative side effects. According to the EPA, volatile organic compounds are associated with irritation of the eyes, nose, and throat, headaches, loss of coordination, and nausea. Prolonged exposure can cause damage to the liver, kidneys, and central nervous system. Whether or not they are carcinogenic is still contested. The EPA and International Agency for Research on Cancer have concluded that some VOCs increase cancer risk in studied animals, and there are some that are suspected to cause cancer in human beings.
How to test for VOCs in water
The only way to effectively test VOCs in water is to take a water sample and send it to a certified laboratory. The National Testing Laboratories' Watercheck test kit makes this process incredibly easy. In addition to bacteria and heavy metals, it tests for trihalomethanes and 44 other VOCs that could be in your water. If you depend on a well for your home water supply, you should test your water for volatile organic compounds every year. The only way to reliably know if your VOC levels are too high is to test your water periodically. Waterborne VOCs don’t necessarily have a smell, a taste, or a color. So, you could unknowingly have high levels of VOCs if you do not run tests on your water.
Learn more: Lab water tests vs at-home water test kits
How to remove VOCs from water
Carbon filters are very effective at removing VOCs from water. Since VOCs are organic compounds, they are carbon based. The adsorption properties of the activated carbon filter allow it to grab hold of the carbon-based VOC. There is no better defense mechanism against VOCs in your water than carbon. Carbon filters come in many various shapes, sizes, and applications. If you have a refrigerator filter containing carbon, it will remove the VOCs from your refrigerator water. You can install carbon filters under the sink, on your counter-top, or even as a whole house filtration system. These filters provide the added benefit of removing chlorine and chloramines, greatly improving the taste of your drinking water throughout your house.
If you are using a point-of-use drinking water filter, ensure it is rated for VOC reduction. VOCs exhaust filtration media much faster than chlorine, so it is important not to overrun the filter's capacity if you wish to reduce the level of VOCs effectively.
Learn more: Activated carbon filters 101
How to remove vinyl chloride from water
Like other VOCs, vinyl chloride can effectively be removed from water using an activated carbon filter. Activated carbon filters are porous, allowing them to trap the vinyl chloride particles and eliminate them from the water through the process of adsorption. This is a common filtration method that is used to eliminate aesthetic contaminants like chlorine and more serious health risks like lead. Not all carbon filters are certified for lead removal, so check the certifications of the filter you choose if lead removal is important to you.
When purchasing a water filter to remove vinyl chloride, pay attention to the filter's lifespan and the contaminants it has been tested to eliminate. Many specialty carbon filters are made specifically with VOC reduction in mind. Activated carbon filters are engineered in a wide variety of sizes and applications. They can be installed in refrigerators, under-sink, or at the entry point of a home or business.
It is important to diligently replace water filters that are installed to remove vinyl chloride or other VOCs. VOCs like vinyl chloride will exhaust carbon filtration media 33% faster than other contaminants. Therefore, if you purchase a water filter that states it has a 6 month lifespan, this is likely referring to its capacity to treat the water for contaminants like chlorine. You will need to replace this filter approximately every two months to ensure that it is still eliminating the vinyl chloride and other VOCs from the water.
If you have reason to suspect your water source has been exposed to vinyl chloride, conduct an at-home lab test or have your water professionally tested. An under-sink or countertop filter is a strong choice to ensure that the drinking water consumed by you and your family is safe. However, if the results reveal significant contamination, installing a whole-house carbon filtration system will ensure that the VOC contamination is eliminated from all water-using appliances, reducing your risk of exposure through bathing, brushing your teeth, laundry, or cleaning dishes.
Does reverse osmosis remove VOCs?
Yes, reverse osmosis (RO) systems reduce levels of VOCs because they contain carbon filtration as a prefilter, postfilter, or both. The RO membrane itself cannot take out VOCs, as they pass through the membrane just like oxygen. Carbon filters are an integral component of reverse osmosis systems, making them an effective method to reduce VOCs in your water. They also reduce far more contaminants than a standard carbon filter because of the RO membrane. These reduce levels of practically all contaminants, leading to some of the most pure water possible from a home water treatment system. Most RO systems are point-of-use systems, meaning they only treat water at one faucet in your home. If you wish to reduce levels of VOCs in all water that enters your home, a whole-house carbon filter is a better option for you.
Learn more: What is a reverse osmosis system?
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