BIRMINGHAM — In Water Technology’s Contaminant of the Month featured in the January issue, Technical Editor Dr. Joseph Cotruvo writes about benzene. Cotruvo takes a closer look at what it is, what it’s used for, human exposure to benzene and the potential health risks, occurrence in water, analytical methods, available water treatment and how it is regulated.

Cotruvo explains in the article that benzene, a natural product in some foods, is a hydrocarbon manufactured from petroleum and is the base product amid the family of BTEX (benzene, toluene, ethylbenzene, xylene) hydrocarbons provided in very high volume.

In the article, Cotruvo also lists health risks associated with benzene:

  • As with most volatile solvents, benzene can cause drowsiness and headaches at high inhalation levels.
  • Benzene is a known human carcinogen — EPA Group A, based upon occupational epidemiology.
  • Leukemias are the principal cancer concern.
  • EPA’s lifetime risk calculation for inhalation is about one in 100,000 to one in one million for exposure at 1 µg/m3.
  • EPA’s calculated risk of one in one million for ingestion through drinking water is between 10 and 100 ppb.
  • The other BTEX hydrocarbons have much less chronic risk than benzene.

Benzene is not detectable in most groundwaters and surface waters, states Cotruvo in the article. However, adds Cotruvo, well water often will be contaminated with benzene when polluted with gasoline from a nearby hazardous waste site or leaking underground storage tanks.

Water treatment options for benzene are also included in the article. “Granular activated carbon and aeration are available to water treatment plants,” he reports in the article. “Reverse osmosis is not effective because an organic solvent, such as benzene, can dissolve in the membrane and migrate to the treated water. POU and POE using activated carbon are effective, however, they must be replaced before exhaustion.”

Cotruvo continues by noting various benzene regulations. The drinking water Maximum Contaminant Level Goal (MCLG) is zero, and the Maximum Contaminant Level (MCL) of benzene is 5 ppb. However, some states, such as Florida and California, have an MCL of 1 ppb. The World Heath Organization advises 10 ppb for benzene. Cotruvo concludes that all of these regulations are conservative values.

You can find January’s Contaminant of the Month on benzene here.