Biodegradation laboratory studies

Cohen BA, LR Krumholz, H Kim, HE Hemond (1995) In-situ biodegradation of toluene in a contaminated stream. 2. Laboratory studies. Environ Sci Technol 29 117-125. 

Laboratory studies have provided inconsistent results regarding the degree to which MTBE is biodegraded anaerobically to end products and the extent to which other oxygenates are biodegraded under anaerobic conditions. 

Laboratory and mixed field/laboratory studies have confirmed that half-order kinetics for DO surface removal rates may be a reasonable approximation for sewer biofilm (Raunkjaeretal., 1997 Bjerre etal., 1998b). These results also showed the influence of readily biodegradable substrate. Furthermore, temperature dependency limited by diffusion is included (Nielsen et al., 1998). The following equation for the aerobic growth rate was therefore used ... 

Laboratory studies indicate that endrin can be biodegraded in various soils under various conditions however, caution should be exercised in extrapolating laboratory results to field conditions. Twenty... 

In all these cases it is important to bear in mind that although the majority of hydrocarbons are readily biodegraded, some are very resistant to microbial attack. It is thus important to run laboratory studies to ensure that the contaminant is sufficiently biodegradable that clean-up targets can be met. 

A further interesting aspect of heterogeneous photochemistry concerns oil spilled at sea near land, which is subjected to environmental effects such as evaporation, dissolution, photo oxidation, dispersion into the water column and biodegradation. The fate of heavy fuel oil stranded on rock was studied under different environmental conditions [87]. Samples exposed to full or reflected sunlight showed depletion of the larger and more alkylated aromatic hydrocarbons and formation of resins, in agreement with reported laboratory studies on thin films of oil. 

LAS is readily biodegradable and is highly removed in sewage treatment processes (2). This material looses rapidly its surfactant properties by primary biodegradation. This goes together with the loss of its parent analytical response and of its toxic properties. A number of detailed laboratory studies have also... 

Identification of components in environmental samples and in samples from laboratory studies of biodegradation and biotransformation is generally based on the application of MS coupled to either GC or LC systems. For environmental samples which may contain only small amounts of the relevant compounds, MS is particularly attractive in view of the extremely small amounts of samples — of the order of nanograms — which are required. An important additional advantage is that since the mass spectrometer can be interfaced with GC, LC, or capillary electrophoresis (CE) systems which incorporate separation procedures, pure samples are not required. Some salient issues in MS in the context of environmental application are summarized briefly as an introduction. Reference should be made to an exhaustive review (Burlingame et al. 1998) for instrumental details and aspects that are not covered here, such as MS of synthetic and natural polymers. 

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