Biocidal compounds

Although the musk fragrances and biocides often are released to the aquatic environment, many of them may be transported to other media, including the atmosphere. As discussed above, the processes in the atmosphere are all chemical degradation processes and the ability for a chemical to reach the atmosphere will depend on the Henry s law constant (Hc). In addition, some of these products may be susceptible to chemical hydrolysis. Table 16.5 lists the musk fragrances and biocide compounds along with the Henry s law constant estimated by EPISuite... 

It is well known that microbial communities exposed to xenobiotic compounds develop the ability to break these compounds down metabolically. This has become particularly obvious from studies of biocidal compounds in the environment. In general, such compounds are readily degraded... 

Each preservative has unique characteristics that might affect its suitability for a particular application. These include factors such as appearance, odour, toxicity, wood species compatibility and availability. The discussion that follows provides a basic background to a wide range of preservative systems. Some of these systems are still in use today, while others have been phased out and others are currently under development. Further discussion of preservative systems can be found elsewhere (Ibach, 1999 Nicholas, 1973b Richardson, 1993 Schultz and Nicholas, 2003). It will be readily apparent from this section that the transition away from traditional heavy metal broad spectrum biocidal compounds to organic chemistries has added significant complication to the wood preserving industry as a whole. 

Biocidal compounds against Entamoeba histolytica, a parasite causing amoebiasis. The Schiff base-related complexes 26 and 27 are active in vitro, metronidazole, (28) is commonly used in the medication of amoebiasis. In the diagram on the left, the activities of metronidazole, the complexes 26, 27 and VO(acac)2 and the free ligands (L) of 26 and 27 are compared. The IC50 values indicate the concentrations at which growth of 50% of the amoebae is inhibited. 

This is formed by applying a polymeric composition containing an oiganic water-resistant polymer, which has associated therewith an effective amount of a biocidal compound to inhibit corrosion, fouling and biocidal buildup on the coils. 

IBRG (2001). A method for the evaluation of biocidal compounds in aqueous-based polymer dispersions, draft 5.3, November 2001, IBRG Polymer Dispersion Group Document IBRG/PD/01 /Oil, IBRG Secretariat, Hook, Hants, UK. 

Phenol, a biocidal compound and the first commonly used disinfectant, is an example of a normally nonbiodegradable substance that can be degraded under appropriate conditions. Acclimated bacteria will break down phenol in dilute water solution. When bacteria are used in waste treatment processes to break down substances such as phenol that are normally biorefractory, acclimated microorganisms are often gathered from sites where the substances in question have been present for some time. For example, sites of crude oil spills serve as sources of bacteria that can biodegrade petroleum wastes. 

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