Dense Nonaqueous Phase Liquids (DNAPLs)

For more information on the DNAPL Website, please contact:

Linda Fiedler
Technology Assessment Branch
(703) 603-7194
fiedler.linda@epa.gov

Overview Policy and Guidance Chemistry and Behavior Ethers (for future development) Halogenated alkanes (for future development) Halogenated alkenes Halogenated monaromatics (for future development) Polychlorinated biphenyls (PCBs) (for future development) Multi-Component Waste (creosotes, coal tars, heavy oils) Coal Tars Creosotes Heavy Oils Other (aniline, benzyl chloride, etc.) (for future development) Environmental Occurrence Toxicology Detection and Site Characterization Treatment Technologies Conferences and Seminars Additional Resources [View Complete DNAPLs Site Map]

Chemistry and Behavior

Multi-Component Waste

Because mixtures are often made from different feedstocks, their composition is extremely variable. The materials considered mixtures for this DNAPL classification lack a predominant chemical component in association with lesser additives or contaminants. Instead they contain hundreds of individual chemicals that can have vastly different chemical properties and behaviors when considered separately.

All of the DNAPL mixtures are more viscous than water—some much more so—and they have a wide range of solubility, K_oc, and K_ow values. Common components, such as some polycyclic aromatic hydrocarbons with high K_ow values, have a tendency to bioaccumulate.

When released to ground water or surface water, mixtures typically behave differently based on their constituents. Coal tars and creosotes sink when released to ground water or surface water. Heavy oils, represented by bunker C and marine fuels, can float, sink, or be neutrally buoyant, depending upon the components used to make them—which can be different every time a product batch is made. Once in the water the more soluble components move into a dissolved phase. Some heavy oils that are released to surface water may float initially but eventually sink after the lighter components have volatilized.

While some components of DNAPL mixtures are biodegradable, if they separate from the mass by dissolving or volatilizing, many are very recalcitrant to biodegradation. Large masses of coal tars have been found at gas manufacturing plants that have been closed for 50 to 100 years.

Other DNAPLs Chemistry and Behavior Topics:

Proceed to "Multi-Component Waste (creosotes, coal tars, heavy oils) > Coal Tars" Return to "Polychlorinated biphenyls (PCBs) (for future development) Introduction"

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Chemistry_and_Behavior/p/6
Last updated on Monday, November 10, 2008