Volatile Organic Compounds in Drinking Water
The term Volatile Organic Compound refers to a variety of chemical compounds that contain carbon and evaporate at relatively low temperatures.
Drinking water that contains VOCs can increase your risk for a variety of health problems. Some VOCs have been proven to cause cancer after prolonged exposure, while others are considered possible cancer risks. VOCs can also cause other health problems.
Sources
VOCs do not occur naturally in drinking water.
Hundreds of VOCs have been produced for use in a variety of products, including gasoline, dry cleaning solvents, and degreasing agents. When these products are improperly stored or disposed of, or when a spill occurs, VOCs can contaminate ground water and drinking water supplies.
Although many VOCs found in drinking water are due to contamination, others may be formed when drinking water is treated with chlorine. The chlorine reacts with organic materials found in water and forms certain VOCs known as chlorination by-products.
The Water Supply Division of the Vermont Department of Environmental Conservation regulates VOCs in public water systems.
Treatment
Reducing the amount of chlorine added to your water, or using an activated carbon filter, can sometimes reduce VOCs formed during chlorination.
If the VOCs are not caused by chlorination, it’s important to find the source. Additional testing may be needed to determine the level of contamination.
Following are two ways to remove VOCs from drinking water:
- Activated Carbon/Charcoal — In this method, water passes through an activated carbon filter. The VOCs bond to active sites in the carbon passages and are removed from the water. Over time, the active sites fill up and the filter is no longer effective. If the filter continues to be used at this point, the VOCs may be released back into the filtered water. It’s also important to follow the maintenance schedule recommended by the manufacturer because disease-causing bacteria can build up in the carbon of poorly maintained filters.
- Reverse Osmosis — In this type of treatment, a thin membrane allows pressurized water to pass through while holding back any pollutants to be drained off. This process uses three to 10 gallons of untreated water to make one gallon of drinking water. Reverse osmosis can remove many VOCs but not all chlorination by-products. Chlorine can damage some reverse osmosis membranes, so pretreatment may be needed.
The First Step
Call the Toxicology and Risk Assessment program of the Vermont Department of Health (863-7220 or 800-439-8550) if Volatile Organic Compounds are found in your drinking water. This program can give you information about possible health risks of specific compounds and how to treat your water.