Bioremediation intrinsic

The broadest view of "aiding and abetting" includes doing nothing, but merely watching natural processes occur without further intervention. This has been termed "Intrinsic Bioremediation", and it too has met with success. From an environmental point of view, although unfortunately not always from a regulatory viewpoint, it is important that any remediation intervention yield a clear net environmental benefit. Sometimes very mild stimulation of intrinsic processes may be the most environmentally responsible option. 

Intrinsic bioremediation is becoming an acceptable option in locations where the contaminated groundwater poses Htde threat to environmental health. Nevertheless, although intrinsic bioremediation is appealingly simple, it may not be the lowest cost option if there are extensive monitoring and documentation costs involved for several years. In such cases it may well be more cost effective to optimize conditions for biodegradation. 

Bradley PM, FH Chapelle (1995) Rapid toluene mineralization by aquifer microorganisms at Adak, Alaska implications for intrinsic bioremediation in cold environments. Environ Sci Technol 29 2778-2781. 

Ahad JME, BS Foliar, EA Edwards, GF Slater, BE Sleep (2000) Carbon isotope fractionation during anaerobic biodegradation of toluene implications for intrinsic bioremediation. Environ Sci Technol 34 892-896. 

Dojka MA, P Hugenholtz, SK Haack, NR Pace (1998) Microbial diversity in a hydrocarbon- and chlorinated-solvent-contaminated aquifer undergoing intrinsic bioremediation. Appl Environ Microbiol 64 3869-3877. 

Bioremediation systems in operation today rely on microorganisms indigenous to contaminated sites. The two main approaches, based on the actions of native microbial communities, are biostimulation and intrinsic bioremediation. In biostimulation, the activity of native microbes is encouraged, creating (in situ or ex situ) the optimum environmental conditions and supplying nutrients and other chemicals essential for their metabolism. The vast majority of bioremediation projects are based on this biostimulation approach. Intrinsic bioremediation is a remedial option that can be applied when there is strong evidence that biodegradation will occur naturally over time without any external stimulation i.e., a capable microbial community exists at the site, the required nutrients are available, and the environmental conditions are favorable. An additional prerequisite is that the naturally... 

Intrinsic bioremediation. This is the unassisted bioremediation of the contaminant the only process carried out is regular monitoring. 

Intrinsically conducting polymers, 13 540 Intrinsic bioremediation, 3 767 defined, 3 759t Intrinsic detectors, 22 180 Intrinsic fiber-optic sensors, 11 148 Intrinsic magnetic properties, of M-type ferrites, 11 67-68 Intrinsic photoconductors, 19 138 Intrinsic rate expressions, 21 341 Intrinsic semiconductors, 22 235-236 energy gap at room temperature, 5 596t Intrinsic strength, of vitreous silica, 22 428 Intrinsic-type detectors, cooling, 19 136 Intrinsic viscosity (TV), of thermoplastics, 10 178... 

The dominantly unsaturated nature of the upper smear zone was also distinct in that it had a substantially lower percentage (10%) of total volatile (gasoline-range) vs. total recoverable (diesel-range) hydrocarbons. In contrast, the lower smear zone contained 25% total volatile hydrocarbons. The difference was thought to be due to the dominantly saturated nature of the lower smear zone, which limited the amount of volatilization that could occur. However, the dramatic difference in TPH concentration was thought to be largely attributable to intrinsic bioremediation. 

Stable carbon isotopes (see Chap. 1) provide a promising new method of validating intrinsic bioremediation. Carbon has two stable isotopes, with 12C comprising 98.89% and 13C comprising 1.11% of the total natural abundance [476]. Because of the magnitude of this abundance gap, the ratios of 13C to 12C in carbon-bearing compounds are expressed as per mil (%o) differences relative to a standard (i.e., <513C vs PDB,see Chap. 1). 

Natural attenuation, often called intrinsic remediation, intrinsic bioremediation, bioattenuation, or monitored natural attenuation (MNA) is an in situ treatment technology for soil, sediment, or groundwater. The technology has been used for full-scale remediation of sites contaminated with volatile organic compounds (VOCs), total petroleum hydrocarbons (TPH), chlorinated solvents, explosives, inorganics, and metals. 

BTEX contamination and will facilitate the directed search for unique metabolites that attest to the occurrence of these microbial processes in the field. The information may also help us to predict the rates of intrinsic bioremediation processes as well as to promote alternate strategies for the restoration of contaminated environments. Ultimately, the fundamental knowledge base will serve as a solid foundation upon which solutions to biotechnological problems may be built. 

Ball, H. A., Hopkins, G. D., Orwin, E. Reinhard, M. (1994). Anaerobic bioremediation of aromatic hydrocarbons at Seal Beach, CA Laboratory and field investigations. Environmental Protection Agency Symposium on Intrinsic Bioremediation of Groundwater, August 30-September 1, 1994, Denver, Colorado. 

Wilson, J. T., Weaver, J. W. Kampbell, D. H. (1994). Intrinsic bioremediation toTCE in ground water at an NPL Site in St. Joseph, Michigan. In Symposium on Bioremedialion of Hazardous Wastes Research, Development and Field Evaluations, pp. 3-10. EPA/600/R-94/075. 

The results from these and other laboratory studies have now led to the testing of various PCB bioremediation approaches in pilot demonstrations. The field trials are designed to demonstrate the applicability of field-scale treatment of soils, with the ultimate goal of commercial-scale bioremediation of PCB-contaminated sites, or demonstrated efficacy of intrinsic bioremediation. 

Finally, another major area of focus continues to be the characterization of intrinsic bioremediation as the most cost-effective cleanup alternative. As part of this strategy further work will need to be conducted on developing risk-based cleanup standards using environmentally acceptable endpoints , including the potential applicability of biostabilization. These approaches are being developed to... 

R. E. Hinchee, J. T. Wilson andD. C. Downey, eds., Intrinsic Bioremediation, Battelle Press, Columbus, Ohio, 1995. 

Hart S (1996) In situ bioremediaton defining the limits, new approaches to engineered and intrinsic bioremediation are being developed and field tested. Environ Sci Technol 30, 398A-401A. 

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