Volatile Organic Compounds (VOCs) In Water

What are Volatile Organic Compounds (VOCs) and how do they get into water? 

Volatile Organic Compounds (VOCs) are chemicals used in the production of plastics, adhesives, paints, gasoline, fumigants, refrigerants, and dry-cleaning solvents. The long-term widespread use of VOCs and their ability to persist and migrate in ground water has led to VOCs being detected in most aquifers throughout the nation. Low concentrations of VOCs in water can produce a sweet, pleasant odor that is easily detected. VOC contamination is likely if you taste or smell the odor of gasoline or solvents in your water. At high levels, some VOCs may damage the central nervous system, the kidneys, or the liver. They may cause irritation upon contact with the skin and may irritate mucous membranes if inhaled. Some VOCs are known or suspected carcinogens.

The 4 most common VOCs detected in USGS aquifer studies were:

#1 – Chloroform – a Trihalomethane

#2 – PCE (Perchloroethene aka Tetrachloroethene) – a solvent

#3 – MTBE (Methyl tert-butyl ether) – a gasoline oxygenate

#4 – TCE (Trichloroethene) – a solvent

Of those four compounds, the most two most likely to exceed Federal drinking water standards were PCE and TCE.

Why are Volatile Organic Compounds (VOCs) Dangerous?

Chlorinated solvents are easily absorbed through the digestive tract (if swallowed) and the lungs (if breathed in). Once absorbed, they move throughout the body in the blood. For a short time, they can collect in the liver, kidneys, brain, or fatty tissues. In the liver, chlorinated solvents change into other substances and eventually pass out of the body. In general, most of these substances are eliminated from the body in a matter of days after the exposure has ended. High amounts of chlorinated solvents were found to cause dizziness, reduce the ability to concentrate and remember, damage the nervous system, and produce an irregular heartbeat in people who are exposed in the workplace and in laboratory animals. Some chlorinated solvents (trichloroethene, tetrachloroethene, methylene chloride, carbon tetrachloride, vinyl chloride, and 1, 2-dichloroethane) at high doses have caused cancer in laboratory animals. Vinyl chloride has also caused liver cancer in people who use this chemical at work.

Fuel components are easily absorbed through the lungs (if breathed in) and the digestive tract (if swallowed). These chemicals are then carried rapidly throughout the body by the blood, mostly to the brain and nervous system. Fuel components can also build up temporarily in the fatty tissues, bone marrow, liver and kidneys. The liver changes these chemicals to other substances (for example, benzene is changed to phenol) so that they can be excreted through the urine. Fuel components can cause drowsiness, dizziness, and headaches at high doses. Long-term exposure to high levels of toluene or xylenes may lead to liver and kidney damage. Benzene is the most toxic of the fuel components and seriously affect the blood cells. Industrial workers exposed to high levels of benzene in the air were at higher risk of developing a type of anemia and having a lower white blood cell count than other unexposed workers. Leukemia, a form of cancer of the white blood cells, was more likely to occur in industrial workers as compared to other workers. There is also limited evidence that benzene can injure the fetus or cause miscarriage. Some people exposed to high levels of MTBE in the air have reported nose and throat irritation. Kidney and liver damage occurred in laboratory animals exposed to high levels of MTBE. Exposure of animals to very high levels of MTBE has caused tumors in several organs of the body.