The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
Nonaqueous Phase Liquids (NAPLs) are hazardous organic liquids such as dry cleaning fluids, fuel oil, and gasoline that do not dissolve in water. A significant portion of contaminated soil and groundwater sites contain NAPLs, and they are particularly hard to remove from the water supply. NAPLs are always associated with human activity, and cause severe environmental and health hazards.
Dense NAPLs (DNAPLs) such as the chlorinated hydrocarbons used in dry cleaning and industrial degreasing are heavier than water and sink through the water column. They can penetrate deep below the water table and are difficult to find when investigating sites for contamination.
Hydrocarbon fuels and aromatic solvents are described as light NAPLs (LNAPLs), which are less dense than water and float. These include lubricants and gasoline, pollutants often associated with leaking gasoline or oil storage tanks.
It is difficult or impossible to remove all of the NAPLs once they are released into the ground. Although many NAPL removal technologies are currently being tested, there have been few field demonstrations capable of restoring an NAPL-contaminated aquifer to drinking-water quality. NAPL contamination can affect aquifers for tens or hundreds of years.
Newell, Charles J.; Bowers, Richard L.; and Rifai, Hanadi S. "Impact of Non-Aqueous Phase Liquids on Groundwater Remediation." In Environmental Expert.com Web site. Available from http://www.environmental-center.com/art icles/article1079/article1079.htm.