Light Non-Aqueous Phase Liquids (LNAPLs)

Definitions

LNAPL (Light Nonaqueous Phase Liquid) - "An LNAPL is one of a group of organic substances that are relatively insoluble in water and are less dense than water. LNAPLs, such as oil, tend to spread across the surface of the water table and form a layer on top of the water table." - U.S. Environmental Protection Agency, 2010

LNAPL – “An acronym for less-dense-than-water nonaqueous-phase liquid. LNAPLs do not mix well with water and are less dense than water. Gasoline and fuel oil are common LNAPLs.” – National Research Council, 1994

LNAPL – “Petroleum chemicals (mainly benzene, toluene, xylene, and benzene derivatives) categorized as light nonaqueous-phase liquids (LNAPLs) tend to form pools and spread laterally (Martel and Ayotte, 1989) because of their low densities.” – Lesage and Jackson, 1992

A cross sectional view of a hypothetical LNAPL spill

Figure has been adapted from Delin and others, 1998, USGS Fact Sheet FS-084-98.

Related Definitions

Non-Aqueous Phase Liquids (NAPLs)

Dense Non-Aqueous Phase Liquids (DNAPLs)

USGS Toxics Program Investigations on LNAPLs

• Crude Oil Contamination in the Shallow Subsurface, Bemidji, Minnesota
• Natural Attenuation Fuel Oxygenates in Ground Water, Laurel Bay, South Carolina
• Natural Attenuation Gasoline in Ground Water, Galloway Township, New Jersey
• Osage-Skiatook Petroleum Environmental Research Project, Oklahoma
• Search the Toxic Substances Hydrology Program's Bibliography for "LNAPLs"

Related Headlines

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• Using Oxygen to Clean Up Ground-Water Contamination
• MTBE Can Degrade Naturally Without Oxygen
• MTBE Biodegrades Naturally in Stream Sediments
• Natural Attenuation of MTBE at Laurel Bay, South Carolina
• How Do You Clean Up Gasoline Spills Naturally?

Other Information on LNAPLs

• Ground Water Issue: Light Non-Aqueous Phase Liquids, U.S. Environmental Protection Agency
• Dense Chlorinated Solvents and other DNAPLs in Groundwater, Center for Groundwater Research

References

Lesage, S., and Jackson, R.E., 1992, Groundwater contamination and analysis at hazardous waste sites: Marcel Dekker, Inc., 552 p.

Martel, R., and Ayotte, P., 1989, Etat de la situation sur la contamination de la nappe souterraine dans la region de Ville Mercier: Ministere de l'Environment du Quebec.

National Research Council, 1994, Alternatives for ground water cleanup: Washington, D.C., National Academies Press, 315 p.

U.S. Environmental Protection Agency, 2010, Waste and cleanup risk assessment glossary: U.S. Environmental Protection Agency, access date July, 27, 2010.