Water Education - Contaminants Facts

Drinking Water Contaminants- Benzene - Page 2

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How much Benzene is produced and released to the environment?

Production of benzene has increased: from about 9.9 billion lbs. in 1984 to over 12 billion lbs. in 1993.

Benzene is released to air primarily from fumes and exhaust connected with its use in gasoline. Other sources are fumes from its production and use in manufacturing other chemicals. In addition, there are discharges into the water from industrial effluents and losses during spills.

From 1987 to 1992, according to the Toxics Release Inventory, releases of benzene to water and land totaled over 2 million lbs. These releases were primarily from petroleum refining industries, with the greatest releases occurring in Texas.

What happens to Benzene when it is released to the environment?

If benzene is released to soil, it will either evaporate very quickly or leach to groundwater. It can be broken down by some soil microbes. It may also be degraded in some groundwaters. 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.

How will Benzene be Detected in and Removed from My Drinking Water?

The regulation for benzene became effective in 1989. Between 1993 and 1995, EPA required your water supplier to collect water samples every 3 months for one year and analyze them to find out if benzene is present above 0.5 ppb. If it is present above this level, the system must continue to monitor the benzene levels.

If contaminant levels are found to be consistently above the MCL, your water supplier must take steps to reduce the amount of benzene so that it is consistently below that level. The following treatment methods have been approved by EPA for removing benzene: Granular activated charcoal in combination with Packed Tower Aeration.

How will I know if Benzene is in my drinking water?

If the levels of benzene exceed the MCL, 5 ppb, the system must notify the public via newspapers, radio, TV, and other means. Additional actions, such as providing alternative drinking water supplies, may be required to prevent serious risks to public health.

Drinking Water Standards:

  • Mclg: zero
  • Mcl: 5 ppb

Benzene Releases to Water and Land, 1987 to 1993 (in pounds):

Top Six States*
Major Industries*
Petroleum refining32,4111,049,800
Primary Metal Ind.133,33918,078
Industrial chemicals73,000250,103
Alkalies, chlorine122,2400

* Water/Land totals only include facilities with releases greater than a certain amount - usually 1000 to 10,000 lbs.

As part of the Drinking Water and Health pages, this fact sheet is part of a larger U.S. EPA publication:
EPA National Primary Drinking Water Regulations

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