Natural attenuation definition

Natural attenuation means 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 hazardous substances in the environment. These in situ processes include: Natural biodegradation; dispersion; dilution; sorption; volatilization; and chemical or biological stabilization, transformation, or destruction of hazardous substances. See WAC 173- 340-370(7) for a description of the expected role of natural attenuation in site cleanup. A cleanup action that includes natural attenuation and conforms to the expectation in WAC 173- 340-370(7) can be considered an active remedial measure.

Natural attenuation means the reduction in the con- centration and mass of a substance, and the products into which the substance breaks down, due to naturally occurring physical, chemical and biological processes.

Natural attenuation. ’ means the reduction in the con- centration and mass of a substance and its breakdown products in groundwater, due to naturally occurring physical, chemical, and biological processes without human intervention or enhancement. These processes include, but are not limited to, dispersion, diffu- sion, sorption and retardation, and degradation processes such as biodegradation, abiotic degradation and radioactive decay.

Examples of Natural attenuation in a sentence

• Natural attenuation processes include a variety of physical, chemical, and biological processes that can act to reduce the mass, mobility, volume, or concentration of contaminants in groundwater.

• Natural attenuation processes can also be destructive, including but not limited to the following chemical processes: aerobic, hypoxic and anaerobic biodegradation, and chemical degradation, including abiotic oxidation processes, hydrolysis and other reactions.

• Natural attenuation processes can be non-destructive, including but not limited to the following physical processes: adsorption, absorption, advection, dispersion, diffusion, dilution from recharge, and volatilization.

• Natural attenuation" is the in situ biotic and abiotic processes through which passive remediation occurs.

• Natural attenuation processes (biodegradation, dispersion, sorption, volatilization) affect the fate and transport of chlorinated solvents in all hydrologic systems.

More Definitions of Natural attenuation

Natural attenuation means a verifiable approach to site rehabilitation that allows natural processes to contain the spread of contamination and reduce the concentrations of contaminants in contaminated groundwater and soil. Natural attenuation processes may include sorption, biodegradation, diffusion, dispersion, volatilization, and chemical reactions with subsurface materials.

Natural attenuation means the reduction in the con- centration and mass of a substance and its breakdown products in groundwater or soils, or both, due to naturally occurring physical, chemical or biological processes.

Natural attenuation means the reduction in the mass or concentration in soils or ground water of a regulated substance, pollutant, contaminant, and the products into which a substance breaks down, due to naturally occurring physical, chemical, and biological processes, without human intervention. "Enhanced natural attenuation" means the enhancement of natural attenuation at a site by the addition of chemicals, biota, or other substances or processes. "Monitored natural attenuation" means the monitoring of natural attenuation as it occurs. The department in its discretion may consider natural attenuation or enhanced or monitored natural attenuation as remediation alternatives for a site when pollution or contamination on a site or property does not pose a threat to human health or the environment, and reasonable safeguards are established under this section or other provisions of state or federal law.

Natural attenuation means the reduction in the mass and concentration in groundwater of a substance, and the products

Natural attenuation means a decrease in concentration of a substance in ground water through operation of natural physical or chemical processes, including but not limited to adsorption, absorption, dilution, phase transfer, oxidation, organic complexation, biodegradation, dispersion and diffusion.

Natural attenuation means a reduction in mass or concentration of a chemical of concern in groundwater over time or distance from the release point due to naturally occurring physical, chemical, and biological processes, such as: biodegradation, dispersion, dilution, sorption, and volatilization.

Natural attenuation means the reduction in the mass or concentration in soils or