Posted January 15th, 2015

The Risk of Benzene in Drinking Water, and How to Get Rid of It

Benzene was featured in the January 2015 Water Technology’s “Contaminant of the Month” feature.


Here are some highlights:


Benzene is  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.


Health risks assessment:

  • 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 present in most groundwaters and is most of ten found when wells are contaminated with gasoline from hazardous waste sites or leaking underground storage tanks.



Treatment options:  Activated carbon and aeration are effective for water treatment plants.  For point-of-entry or point-of-use: Activated carbon is effective, but cartridges or carbon beds must be replaced before exhaustion. Although reverse osmosis membranes are not effective because benzene can dissolve and migrate through to the treated water, the carbon filters that go with reverse osmosis units make reverse osmosis a good option.

Regulation figures:

EPA’s MCLG (Maximum Contamintant Level Goal) — 0.
EPA’s MCL (Maximum Contaminant Level) — 5 ppb.
Florida and California MCL — 1 ppb.
World Health Organization MCL – 10 ppb.

You can find Water Technology’s  Contaminant of the Month assessment of benzene here.