Polychlorinated biphenyls mineralization

Eaton DC (1985) Mineralization of polychlorinated biphenyls by Phanerochaete chrysosporium, a lignolytic fungus. Enzyme Microbiol Technol 7 194-196. 

Hickey WJ, DB Searles, DD Focht (1993) Enhanced mineralization of polychlorinated biphenyls in soil inoculated with chlorobenzoate-degrading bacteria. Appl Environ Microbiol 59 1194-1200. 

In the past, mineral oil hydraulic fluids sometimes included additives such as polychlorinated biphenyls (PCBs) to improve the thermal resistance or other properties of the resulting fluids. These additives may present more toxicity risks than the primary ingredients of the hydraulic fluids. While such uses of PCBs have been discontinued, PCBs may be encountered as components of hydraulic fluids at NPL sites contaminated by hydraulic fluids (ATSDR 1993b). 

Chemicals degraded by WRF include pesticides such as organochlorines DDT and its very toxic metabolite DDE [8, 9] and organophosphate pesticides such as chlorpyrifos, fonofos and terbufos [10] polychlorinated biphenyls (PCBs) of different degrees of chlorine substitution [11-13], some even to mineralization [14, 15] diverse polycyclic aromatic hydrocarbons (PAHs) in liquid media and from contaminated soils or in complex mixtures such as creosote [16-18] components of munition wastes including TNT and its metabolites DNT [19-23], nitroglycerin [24] and RDX [25]. 

HCZyme has been demonstrated in bench-scale tests and at field remediations to be effective on benzene, toluene, ethylene, and xylene (BTEX), Polycyclic aromatic hydrocarbons (PAHs), trichloroethylene (TCE), dichloroethylene (DCE), mineral spirits, fuel oils, motor oils, and hydraulic fluids. The vendor claims that HCZyme has been tested and used on over 2 million tons of petroleum-contaminated soils and is effective in breaking down petroleum hydrocarbons, polychlorinated biphenyls (PCBs), creosote, sludges, waste oils, free product, tank bottoms, and other chlorinated compounds (D18208L, p. 15). 

Eaton, D. C. (1985). Mineralization of polychlorinated biphenyls b y Phanerochaete chrysosporium a ligninolytic fungus. Enzyme and Microbial Technology, 7, 194-6. 

Zeddel, A., Majcherczyk, A. Huttermann, A. (1994). Degradation and mineralization of polychlorinated biphenyls by white-rot fungi in solid-phase and soil incubation experiments. In Bioremed tation of Chlorinated and Polycyclic Aromatic Hydrocarbon Compounds, ed. R. E. Hinchee, A. Leeson, L. Semprini S. K. Ong, pp. 436-40. New York Lewis Publishers. 

The system for classification and disposal of hazardous chemical waste developed by EPA under RCRA does not apply to all wastes that contain hazardous chemicals. For example, wastes that contain dioxins, polychlorinated biphenyls (PCBs), or asbestos are regulated under the Toxic Substances Control Act (TSCA). In addition, the current definition of hazardous waste in 40 CFR Part 261 specifically excludes many wastes that contain hazardous chemicals from regulation under RCRA, including certain wastes produced by extraction, beneficiation, and processing of various ores and minerals or exploration, development, and use of energy resources. Thus, the waste classification system is not comprehensive, because many potentially important wastes that contain hazardous chemicals are excluded, and it is not based primarily on considerations of risks posed by wastes, because the exclusions are based on the source of the waste rather than the potential risk. 

The Hydrophobic Effect Hydrophobic Sorption Hydrophobic ( water-hating ) compounds, for example, hydrocarbons and chlorinated hydrocarbons such as the polychlorinated biphenyls are soluble in many nonpolar solvents but not readily soluble in water. Because of the incompatibility of the hydro-phobic substance with water, these substances have a tendency to avoid contact with water and seek to associate with nonpolar environments such as the surface of a mineral or an organic particle (Tanford, 1980). The sorption of hydro-phobic substances to solid materials (particles, soils, sediments) that contain organic carbon may be compared with the partitioning of a solute between two solvents—water and the organic phase. 

Unwanted polychlorinated biphenyl (PCB) formulations and waste materials containing PCBs are normally destroyed by high temperature incineration. However, this is a relatively costly method of waste disposal and alternative, but illegal, practices are known to occur, such as dissolving PCBs in waste mineral oil. Unless the oil is chemically analysed for the presence of the CBs it will pass as waste oil which can be... 

Fava F, Di Gioia D, Marchetti L, et al. 1993. Aerobic mineralization of chlorobenzoates by a natural polychlorinated biphenyl-degrading mixed bacterial culture. Appl Microbiol Biotechnol 40(4) 541-548. 

Bioaccumulation results when uptake of chemicals by dietary and nondietary pathways exceeds metabolism and excretion. Rates at which substances are absorbed, altered, and then excreted are relatively important. Bioaccumulation may involve sequestration mechanisms, such as the deposition of polychlorinated biphenyls (PCBs) in fat, or the incorporation of lead in the mineral portion of bone. Incorporation into fat is dependent on the lipophilicity of the compound. The most commonly performed test of lipophilicity involves experimental determination of the equilibrium partitioning of a test compound between octanol, a nonmiscible organic solvent, and water, often expressed as the log10 of the ratio or the octanol/ water partition coefficient (log K ). Organic compounds in which the log Kow value is less than 3.5 do not appreciably accumulate in the lipids of mammals [5], Because energetic compounds have relatively low log Kow values (Table 10.1), bioaccumulation cannot be explained solely by lipophilicity. 

Polychlorinated biphenyls (PCB) are determined by photometric or gas chromatographic methods. In the former method, the polychlorinated biphenyls are determined by spectrophotometry indirectly, via mercury rho-danide after their mineralization with metallic sodium in ethanol. In the latter determination, a flame ionization detector is used [33]. 

FIGURE 13.13 Microbial mineralization rates of " C-labeled polychlorinated biphenyls at pH 6.5 under controlled redox potential showing degradation was greater under intermediate redox potential +250 mV. 

Fairbanks BC, O Connor GA, Smith SE (1987) Mineralization and volatUization of polychlorinated biphenyls in sludge-amended soUs. J Environ Qual 16 18-25 Ekler Z (1988) Behavior of thiocarbamate herbicides in soUs adsorption and volatUization. Pestic Sci 22 145-157... 

Ethylhexanol Glyceryl hydroxystearate Isostearyl alcohol Linoleyl alcohol Methoxy tri propylene glycol acrylate Methyl acid phosphate Methyl methacrylate Mineral oil Nonoxynol-1 Nonoxynol-3 Octyl acrylate Oleic amidoethylimidazoline PEG-8 ditallate PEG-12 ditallate PEG-115M Pine lignin Poloxamer 124 Polyaspartic acid homopolymer, sodium salt Polybutene Polychlorinated biphenyls Polyvinyl alcohol (partially hydrolyzed) Sodium alum Sodium sulfite Sorbose Stearyl hydroxyethyl imidazoline Triacetin Trimethyl-1,3-pentanediol, 2,2,4-diisobutyrate Tris [1-(2-methyl-aziridinyl) phosphine oxide] paper additive... 

To assess multiple vehicles, an in vitro decontamination technique was developed to evaluate the removal of Aroclor 1242 and polychlorinated biphenyls (PCBs). Surprisingly, PCBs would not move from the SC into water (<1 %). When soap-and-water was used, 33 % was removed, mineral oil removed 66.7 %, and ethanol removed 85 % of the skin-stored PCBs [92,161,173,174], hi an attempt to decontaminate skin exposed to Aroclor 1242 in the rhesus monkey, no differences were seen through 1 h, but from 3 to 24 h the amount removed by any decontamination solution decreased. By 24 h, only 25 % of PCBs apphed to the skin could be removed from the surface. With a mineral oil vehicle, soap-and-water removed approximately 70 % of the applied PCBs over 3 h, 50 % at 6 h, and 30 % at 24 h. However, as seen in vivo, an in vitro study suggested that ethanol, not soap-and-water, would be more efficient [152, 174]. 

Many recent fires involving polychlorinated biphenyls (PCB) are raising more and more concern in the general population, to the workers and firemen. The most important problem is fires of electrical equipment insulated with either "pure" PCB, or PCB mixed with other solvents like the tri- and tetrachlorobenzenes, often present in the askarels. A related problem less serious but arousing a lot of worries is the electrical equipment insulated with mineral oils contaminated with PCB (from concentration of a few ppm to more than 500 ppm). We estimate that approximately 10 % of the transformers in service insulated with oil are contaminated with more than 50 ppm. 

PCBs (polychlorinated biphenyls) are widely used in the electrical industry because they have definite advantages over mineral oil, which used to be the standard insulating fluid for electrical equipment. However, since PCBs tend to be non-biodegradable and to accumulate in the tissues of living organisms, most industrialized countries have prohibited the sale of electrical equipment (transformers and capacitors, both new and used) containing this chemical. Two problems now remain what to use instead of PCBs, and how to dispose of PCBs in a way that does not harm the environment. 

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