Groundwater biodegradation

Once released to surface water, 1,1,1-trichloroethane is expected to undergo volatilization to the atmosphere. Neither adsorption to sediment nor bioconcentration in aquatic organisms is recognized as an important removal process. Aerobic biodegradation of 1,1,1-trichloroethane can occur in the presence of methane-oxidizing bacteria. If released to groundwater, biodegradation of... 

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. 

Kinetics of Pesticide Biodegradation. Rates of pesticide biodegradation are important because they dictate the potential for carryover between growing seasons, contamination of surface and groundwaters, bio accumulation in macrobiota, and losses of efficacy. Pesticides are typically considered to be biodegraded via first-order kinetics, where the rate is proportional to the concentration. Figure 2 shows a typical first-order dissipation curve. 

Models of chemical reactions of trace pollutants in groundwater must be based on experimental analysis of the kinetics of possible pollutant interactions with earth materials, much the same as smog chamber studies considered atmospheric photochemistry. Fundamental research could determine the surface chemistry of soil components and processes such as adsorption and desorption, pore diffusion, and biodegradation of contaminants. Hydrodynamic pollutant transport models should be upgraded to take into account chemical reactions at surfaces. 

Jury WA, Focht DD, Farmer WJ. 1987a. Evaluation of pesticide groundwater pollution potential from standard indices of soil-chemical adsorption and biodegradation. J Environ Qual 16 422-428. 

Seller HR (2002) Analysis of benzylsuccinates in groundwater by liquid chromatography/tandem mass spectrometry and its use for monitoring in situ BTEX biodegradation. Environ Sci Technol 36 2724-2728. 

Zwank L, M Berg, M Eisner, TC Schmidt, RP Schwarzenbach, SB Haderlien (2005) New evaluation scheme for two-dimensional isotope analysis to decipher biodegradation processes application to groundwater contamination by MTBE. Environ Sci Technol 39 1018-1029. 

The collective evidence suggests the variable recalcitrance of MTBE under aerobic conditions, a degree of recalcitrance anaerobic conditions, and that the presence of the putative degradation product tert-butanol cannot necessarily be construed as evidence for biodegradation (Landmeyer et al. 1998). Bioremediation of groundwater contaminated with MTBE is clearly beset with problems for its practical implementation. 

Biodegradation as a result of the enrichment of the groundwater with oxygen... 

Johnston, C.D., Rayner, J.L., Patterson, B.M. and Davis, G.B., Volatilisation and biodegradation during air sparging of dissolved BTEX-contaminated groundwater, J. Contam. Hydrol., 33, 377-404, 1998. 

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