Polychlorophenols

MIcrobiocldes. There are several microbiocides available commercially that can perform an effective function in controlling microbial activity. Some of these chemicals are inorganic, such as chlorine, sodium hypochlorite, calcium hypochlorite, hydrogen peroxide, chromates and compounds of mercury and silver. However, the organic chemicals find the highest use as microbiocides. Some examples of these organic compounds are peracetic acid, paraformaldehyde, polychlorophenols and quaternary ammonium derivatives, to name a few [208]. 

Haggblom MM, LJ Nohynek, NJ Palleroni, K Kronqvist, E-L Nurmiaho-Lassila, MS Salkinoja-Salonen, S Klatte, RM Kroppenstedt (1994) Transfer of polychlorophenol-degrading Rhodococcus chloropheno-licus (Apajalahti et al. 1986) to the genus Mycobacterium as Mycobacterium chlorophenolicum comb, nov. Int J Syst Bacteriol 44 485-493. 

Tiirola MA, MK Mannisto, JA Puhakka, MS Kulomaa (2002) Isolation and characterization of Novosphingobium sp. strain MTl, a dominant polychlorophenol-degrading strain in a groundwater bioremediation system. Appl Environ Microbiol 68 173-180. 

Precipitation usually occurs when the concentration of a compound in solution exceeds the equilibrium solubility, although slow reaction kinetics may result in supersaturated solutions. For organic wastes in the deep-well environment, precipitation is not generally a significant partitioning process in certain circumstances, however, it may need to be considered. For example, pentach-lorophenol precipitates out of solution when the solution has a pH of <5,35,36 and polychlorophenols form insoluble precipitates in water high in Mg2+ and Ca2+ ions.37 Also, organic anions react with such elements as Ca2+, Fe2+, and Al3+ to form slowly soluble to nearly insoluble compounds. 

Gihr and co-workers 8 estimated PCDD/F sources to sewage sludge and made two important observations. Firstly, known sources of PCDD/Fs (like polychlorophenols - PCP) cannot explain the total burden in sewage sludge and secondly, that while PCP-associated PCDD/Fs can account for the... 

There are 210 different isomeric possibilities, 75 of which are PCDDs and 135 are PCDFs. The toxicity of these isomers varies greatly, and only 15 exhibit extreme toxicity, the most toxic of which is 2,3,7,8-tetrachlorodibenzodioxin (2,3,7,8-TCDD). The toxicity of the other isomers is therefore expressed as a toxicity equivalent of 2,3,7,8-TCDD. The PCDDs and PCDFs are poorly water soluble but are fat soluble and are therefore able to accumulate in tissue fat, thus allowing them to bio-accumulate in living organisms. The origin of dioxins in the pulp and paper industry is not entirely clear. They may be produced from the chlorination of dibenzodioxin which may be present in recycled oils used to make defoamers, but they may also arise from wood chips which have been treated with polychlorophenol to prevent sap stain formation. It is also possible that they are derived from lignin by chlorination. Dioxins are also known to be formed naturally by combustion of material such as wood, and forest fires have been particularly identified as a likely major cause of dioxin emissions. 

Lee [42] determined pentachlorophenol and 19 other chlorinated phenols in sediments. Acidified sediment samples were Soxhlet extracted (acetone-hexane), back extracted into potassium bicarbonate, acetylated with acetic anhydride and re-extracted into petroleum ether for gas chromatographic analysis using an electron capture or a mass spectrometric detector. Procedures were validated with spiked sediment samples at 100,10 and lng chlorophenols per g. Recoveries of monochlorophenols and polychlorophenols (including dichlorophenols) were 65-85% and 80-95%, respectively. However, chloromethyl phenols were less than 50% recovered and results for phenol itself were very variable. The estimated lower detection limit was about 0.2ng per g. 

A UV/ozone Ultrox system was used to treat wastewater contaminated with phenol and polychlorophenol (PCP) at a wood processing facility in Denver, Colorado. The capital cost for the Ultrox system was 200,000. Operation and maintenance costs for the entire remediation system were 10.92 per 1000 gal of treated wastewater. This cost estimate excludes the expenses associated with site preparation, permitting and regulatory compliance, startup, analysis, effluent disposal, and demobilization (D205505, p. C-1). 

Chlorophenols (see also Polychlorophenols and their sodium salts) Chlorophenols (occupational exposures to)... 

Polychlorinated dibenzofurans Polychlorophenols and their sodium salts Polychloroprene... 

There is limited evidence in humans for the carcinogenicity of combined exposures to polychlorophenols or to their sodium salts. 

Polychlorodibenzofurans are extremely toxic trace atmospheric contaminants which can be detected and identified in manufactured polychlorophenols and thus may appear in a variety of industrial chemical products. They are toxic to mammals, causing chloracne and producing extensive irreversible liver damage (76JOC2428). 

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