Volatile Organic Compounds (VOCs) are a widespread family of human-made chemicals that challenge water quality. These substances can enter public water supplies and private wells, often going undetected because they are odorless and colorless at low concentrations. Exposure is a concern because it can occur through drinking, inhalation, and skin contact. VOCs are frequently found in groundwater due to their common use in industrial and household products, requiring specialized testing and treatment.
Defining Volatile Organic Compounds
Volatile Organic Compounds are defined by two characteristics: they contain carbon (“organic”) and they easily change into a gas at normal temperatures (“volatilize”). This volatility poses a dual threat: they can be ingested through drinking or rapidly escape into the air during everyday activities like showering or cooking.
The organic nature of these compounds allows them to dissolve and be transported through water, especially groundwater. Common examples include benzene and toluene, components of gasoline and petroleum products. Other prevalent VOCs are industrial solvents like trichloroethylene (TCE) and tetrachloroethylene (PCE), used in dry cleaning and metal degreasing operations.
Common Sources of VOC Contamination
VOCs primarily enter water supplies through human activity, typically categorized into industrial, environmental, and household sources.
Industrial facilities and commercial businesses are major contributors, releasing VOCs through manufacturing discharge or improper disposal of solvents and degreasers. For example, facilities that use solvents to clean machinery may allow chemicals to seep into the ground and migrate into the water table.
Environmental sources include leaking underground storage tanks (USTs), often found at gasoline stations, which release petroleum-based VOCs like benzene directly into the soil and groundwater. Agricultural runoff also carries VOCs, such as pesticides and herbicides, which leach through the soil after application.
Household activities contribute through the improper disposal of common products. Pouring paint thinners, cleaning agents, or automotive fluids onto the ground allows these chemicals to find their way into septic systems or groundwater. Furthermore, certain septic system cleaners containing VOCs like TCE can directly contaminate a private well system’s environment.
Health Effects of VOC Exposure
Exposure to VOCs in contaminated water occurs through ingestion, dermal absorption while bathing, or inhalation of vapors released during hot water use. Health risks are generally divided into acute effects from short-term exposure and chronic effects from long-term exposure.
Acute effects are typically noticeable sooner and may include symptoms such as dizziness, nausea, headaches, and irritation of the eyes, nose, and throat.
Chronic exposure, occurring at low concentrations over many years, is linked to severe systemic damage. Certain VOCs, such as benzene and vinyl chloride, are classified as human carcinogens and significantly increase the risk of cancer. Other compounds affect major organs, potentially leading to liver and kidney damage or nervous system disorders.
The severity of the health impact depends on the specific chemical, its concentration in the water, and the duration of exposure. Because VOCs readily vaporize, activities like showering or doing laundry can concentrate the chemicals in the air inside the home, increasing the risk of inhalation exposure.
Testing and Treating VOCs in Water
The first step in addressing potential VOC contamination is testing the water by a certified laboratory, as these chemicals are often undetectable by smell or taste. Laboratory testing uses precise analytical methods, such as gas chromatography, to identify and quantify the trace amounts of VOCs present. Standard home testing kits are insufficient for accurately measuring these low concentrations.
Treatment Methods
Once contamination is confirmed, the most effective residential treatment method is activated carbon filtration, specifically using Granular Activated Carbon (GAC) or carbon block filters. Carbon filters work through adsorption, where VOC molecules adhere to the porous surface of the carbon material, trapping them as water passes through. For whole-house treatment, a Point-of-Entry GAC system is recommended to treat all water used for drinking and bathing.
Another effective treatment option for highly volatile compounds is aeration, often called air stripping, which encourages VOCs to rapidly transition from the water into the air. Consumers should never attempt to remove VOCs by boiling their water. Boiling causes VOCs to vaporize more quickly, concentrating harmful chemical vapors in the air and increasing the risk of inhalation exposure.