Natural Attenuation
Several organizations have developed definitions for natural attenuation.
- The U.S. Environmental Protection Agency defines monitored natural attenuation as
the
- "reliance on natural attenuation processes (within the context of a carefully controlled and monitored
site cleanup approach) to achieve site-specific remediation objectives within a time frame that is reasonable compared to
that offered by other more active methods. The 'natural attenuation processes' that are at work in such a remediation
approach include a variety of physical, chemical, or biological processes that, under favorable conditions, act without
human intervention to reduce the mass, toxicity, mobility, volume, or concentration of contaminants in soil or
groundwater. These in-situ processes include biodegradation; dispersion;
dilution; sorption; volatilization; radioactive decay; and chemical or biological stabilization, transformation, or
destruction of contaminants." (EPA, OSWER Directive
9200.4-17P)
The American Society for Testing and Materials (ASTM) defines natural attenuation as
the - "reduction in mass or concentration of a compound in groundwater over time or distance from the source
of constituents of concern due to naturally occurring physical, chemical, and biological processes, such as;
biodegradation, dispersion, dilution, adsorption, and volatilization."
(ASTM,
E1943-98)
The U.S. Air Force Center for Environmental Excellence defines
natural attenuation as the processes resulting - "from the integration of several subsurface attenuation
mechanisms that are classified as either destructive or nondestructive. Biodegradation is the most important destructive
attenuation mechanism. Nondestructive attenuation mechanisms include sorption, dispersion, dilution from recharge, and
volatilization." (Wiedemeier,
1999)
The U.S. Army defines natural attenuation as - "the reduction of
contaminant concentrations in the environment through biological processes (aerobic and anaerobic
biodegradation, plant and animal uptake), physical phenomena (advection, dispersion, dilution, diffusion,
volatilization, sorption/desorption), and chemical reactions (ion exchange, complexation, abiotic transformation). Terms
such as intrinsic remediation or bio-transformation are included within the more general natural attenuation
definition." (U.S. Army,
1995)
Related Headlines
USGS Information on Natural Attenuation
Other Information on Natural Attenuation
- Natural Attenuation for Groundwater Remediation, 2000: National
Academies Press
- In Situ Bioremediation: When Does it Work?,1993:
National Academies Press
- U.S. Environmental Protection Agency
- Technology
Focus: Natural Attenuation, Clu-In, Technology Innovation Office
- A Citizen's Guide to Natural Attenuation, Clu-In,
Technology Innovation Office
- Monitored Natural Attenuation: It's Much More Than Watching The
Grass Grow!, Office of Underground Storage Tanks
- Issues Associated With Natural Attenuation, Office of
Underground Storage Tanks
- Technical Protocol for Evaluating
Natural Attenuation of Chlorinated Solvents in Ground Water: Office of Research and Development, EPA/600/R-98/128
- Use of Monitored Natural Attenuation at Superfund,
RCRA Corrective Action, and Underground Storage Tank Sites, An U.S. EPA directive (April 21, 1999) on the use of monitored natural attenuation for the remediation of contaminated soil and groundwater
- Proceedings of the Symposium on Natural Attenuation of Chlorinated Organics in Ground Water
- Listing of EPA Monitored Natural Attenuation
Documents
- Listing of Non-EPA Monitored Natural Attenuation
Documents
- U.S. Department of Energy
- Natural Attenuation Of Organic Compounds, Center for Public
Environmental Oversight, San Francisco State University
- Technical Guidelines for Evaluating
MNA of Petroleum Hydrocarbons and Chlorinated Solvents in Ground Water at Naval and Marine Corps Facilities (pdf),
U.S. Navy
- Natural Attenuation Software (NAS)
References
- ASTM International, 2003, E1943-98
Standard
guide for remediation of ground water by natural attenuation at petroleum release sites: ASTM Book of Standards, v.
11.04, 43 p.
- U.S. Army, 1995, Interim army
policy on natural attenuation for environmental restoration: Washington, DC, Department of the Army, Assistant Chief
of Staff for Installation Management, DAIM-ED-R (200-1c), September 12, 1995.
- U.S. Environmental Protection Agency, 1999, OSWER
Directive 9200.4-17P -- Use of monitored natural attenuation at Superfund, RCRA corrective action, and underground
storage tank sites -- April 21, 1999: Office of Solid Waste and Emergency Response, 41 p.
- Wiedemeier, T.H., Wilson, J.T., Kampbell, D.H., Miller, R.N. and Hansen, J.E., 1999,
Technical protocol for implementing
intrinsic remediation with long-term monitoring for natural attenuation of fuel contamination dissolved in
groundwater: U.S. Air Force Center for Environmental Excellence, v. 1 & 2, A324248, A324247a, A324247b.
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