A Few Things You Should Know about Benzene

by Pure Water Annie

Benzene is a known carcinogen. There is a lot of it around. You’d do best to take in as little as possible.

This piece appeared originally in the Pure Water Occasional for February 2012. Benzene has emerged more recently as a major water contaminant related to wildfires. See Benzene Pollution after California Fire.

Benzene is an organic chemical, one of the aromatic hydrocarbons. It is essentially colorless and has a slightly sweet odor. It is highly flammable. Benzene dissolves easily in water and evaporates quickly at room temperature. It boils at 176 degrees F.

Benzene has been much in the news recently because of its presence in the fracking fluids being injected into the ground by gas well producers, but it can contaminate water via many other sources.

Natural sources of benzene include volcanoes and forest fires. Benzene is also a natural part of crude oil, gasoline and cigarette smoke. Burning PVC also produces benzene. Some industries use benzene to make other chemicals that are used to make plastics, resins, nylon and synthetic fibers. Benzene is also used to make some types of lubricants and pesticides.

Benzene can cause cells not to work correctly, leading to conditions such as anemia. It can damage the immune system by changing blood levels of antibodies and causing the loss of white blood cells.

An ingredient of gasoline, benzene is found in groundwater contaminated by leaking underground fuel storage tanks, or in surface water subject to fuel spills. Gasoline contains a bit less than 1% benzene. Produced from coal or petroleum (usually the latter), benzene ranks among the top 20 chemicals in production volume. Benzene is used to make solvents, detergents, plastics, resins, paint and many other products.

Benzene is a carcinogen in humans. Also, long exposure to high levels in air causes leukemia. People who are exposed over long periods in their workplace are most at risk.

Drinking water or eating food containing high levels of benzene can cause vomiting, dizziness, or even death.

The EPA regulates benzene. The MCL for benzene in water is 0.005 mg/L (5 ppb).

If exposed to air, benzene evaporates to the environment. It can also be broken down by some soil microbes. It may also be degraded in some ground waters. If benzene is released to surface water, most of it should evaporate within a few hours. Though it does not degrade by reacting with water, it may be degraded by microbes. It is not likely to accumulate in aquatic organisms.

Benzene can be removed from water by adsorption with granular activated carbon. It can also be treated by ozonation. Because benzene evaporates easily, open tank aeration is also a valuable treatment method. If benzene is present, it should be treated as a “whole house” or point of entry issue because inhalation is a hazard. The most practical residential treatment is filtration with a good activated carbon filter.

Sources: US EPA, US Occupational Safety and Health Administration, US Centers for Disease Control and Prevention, Clean Water Partners. Water Technology Volume 32, Issue 4 – April 2009