Aromatic polychlorinated compounds

Fish hepatocyte lines have also been developed, which can show cytochrome P450 lAl induction due to PAHs and planar polychlorinated aromatic compounds binding to the Ah receptor (Vaillant et al. 1989, Pesonen et al. 1992). 

QSAR modeling of polychlorinated aromatic compounds. Indian Journal of Chemistry, 42A, 1368-1378. 

Jackson, D. R. Bisson, D. L. (1990). Mobility of polychlorinated aromatic compounds in soils contaminated with wood-preserving oil. Journal of Air Waste Management Association, 40, 1129—33-... 

Kitunen, V. H., Valo, R.J. Salkinoja-Salonen, M. S. (1987). Contamination of soil around wood-preserving facilities by polychlorinated aromatic compounds. Environmental Science and Technology, 21, 96-101. 

In addition to PCBs and polychlorinated dioxins and furans, there are other groups of widely distributed polychlorinated aromatic compounds ... 

Polychlorinated aromatic compounds may yield polychlorinated dibenzodi-oxins and polychlorinated dibenzofurans (see p 184) when heated. 

Clothes-moth [13,175,269,270] larvae attack wool with a mixture of enzymes that catalyze the reduction of cystine residue disulfide cross-links and the hydrolysis of peptide bonds. Wool is usually moth-proofed by treatment with insecticides that are absorbed like dyes and show similar fastness. The wool textile industry applies insect-resistant agents mainly to carpet wools, which account for about 85% of the treated wool. Insect-resistant agents are of two classes those which have been developed specifically for use on wool, and those which consist of agricultural insecticides that have been specially formulated for use with wool. The former group is usually polychlorinated aromatic compounds, and the latter group is based on synthetic pyrethroid insecticides. 

Lubke, M. Whitcombe, M.J. Vulfson, E.N. A novel approach to the molecular imprinting of polychlorinated aromatic compounds. J. Am. Chem. Soc. 1998,120,13342-13348. Hansch, C. Leo, A. Hoekman, D.H.. In Exploring QSAR American Chemical Society Washington, DC, 1995. 

The pyrolysis of vinylidene chloride produced a range of chlorinated aromatic compounds including polychlorinated benzenes, styrenes, and naphthalenes (Yasahura and Morita 1988), and a series of chlorinated acids including chlorobenzoic acids has been identified in emissions from a municipal incinerator (Mowrer and Nordin 1987). 

The quantitative environmental analysis of surfactants, such as alcohol ethoxylates, alkylphenol ethoxylates (APEOs) and linear alkylbenzene sulfonates (LASs), is complicated by the presence of a multitude of isomers and oligomers in the source mixtures (see Chapter 2). This issue bears many similarities to the quantitation problems that have occurred with halogenated aromatic compound mixtures, e.g. polychlorinated biphenyls (PCBs) [1]. 

Such xenobiotics as aliphatic hydrocarbons and derivatives, chlorinated ahphatic compounds (methyl, ethyl, methylene, and ethylene chlorides), aromatic hydrocarbons and derivatives (benzene, toluene, phthalate, ethylbenzene, xylenes, and phenol), polycyclic aromatic hydrocarbons, halogenated aromatic compounds (chlorophenols, polychlorinated biphenyls, dioxins and relatives, DDT and relatives), AZO dyes, compounds with nitrogroups (explosive-contaminated waste and herbicides), and organophosphate wastes can be treated effectively by aerobic microorganisms. 

Although a variety of structures were represented by these negative K values, among the substituted aromatic compounds a pattern was observed. Whereas polychlorination often was associated with the repellency of compounds, polybrumination appeared to confer "antirepellency" effects. The K-values shown in Table I illustrate this point. Although "antirepellency" isn t necessarily a direct measure of attractiveness of compounds, it gave us a rationale for our choice of substituents ring. 

The ARS Technologies, Inc., Ferox process is an in situ remediation technology for the treatment of chlorinated hydrocarbons, leachable heavy metals, and other contaminants. The process involves the subsurface injection and dispersion of reactive zero-valence iron powder into the saturated or unsaturated zones of a contaminated area. ARS Technologies claims that Ferox is applicable for treating the following chemicals trichloroethene (TCE), 1,1,1-trichloroethane (TCA), carbon tetrachloride, 1,1,2,2-tetrachloroethane, lindane, aromatic azo compounds, 1,2,3-trichloropropane, tetrachloroethene (PCE), nitro aromatic compounds, 1,2-dichloroethene (DCE), vinyl chloride, 4-chlorophenol, hexachloroethane, tribromomethane, ethylene dibromide (EDB), polychlorinated biphenyls (PCBs), Freon-113, unexploded ordinances (UXO), and soluble metals (copper, nickel, lead, cadmium, arsenic, and chromium). 

The vendor claims that the TDR process can be used to treat soil and sludge contaminated with polychlorinated biphenyls, polynuclear aromatic compounds, solvents, dioxins, furans, organic pesticides and herbicides, solvents, petroleum wastes, as well as nonhalogenated volatile and semivolatile compounds. The treated residuals from the process include recovered water, oil that can be used for recycling as an alternative fuel or for recycling or can be disposed, and clean soil that can be used as backfill. The volume of treated sludge is reduced by as much as 95% by this thermal process, depending on the initial level of contaminants. 

The desorption and vapor extraction system (DAVES) uses a low-temperature fluidized bed to remove volatile and semivolatile organics such as polychlorinated biphenyls (PCBs), polynuclear aromatic compounds (PAHs), pentachlorophenol (PCP), volatile inorganics (tetraethyl lead), and some pesticides from soil, sludge, and sediment. The process generally treats waste containing less than 10% total organic contaminants and 30 to 95% solids. The process does not treat nonvolatile inorganic contaminants such as metals. 

Supercritical carbon dioxide extraction (SCDE) is an ex situ process currently being researched for the treatment of soil and debris contaminated with polychlorinated biphenyls (PCBs) and polycyclic aromatic compounds (PAHs) as well as for the removal of solvents from low-level solid mixed wastes and land disposal restricted (LDR) wastes. 

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) are two series of tricyclic aromatic compounds which exhibit similar physical and chemical properties. Some of these compounds have extraordinary toxic properties and were the subject of much concern. They have been involved in accidents like the Yusho accident in Japan 1968 l 9 the intoxication at horse arenas in Missouri, USA in 1971 (2.) and the accident near Seveso, Italy in 1976 (3.). The chemical structures and the numbering of these hazardous compounds are given below. 

Reductive dehalogenation of chlorinated phenols to phenol, cyclohexanol and other chlorine-free compounds takes place rapidly with hydrogen gas and Pd/C in an aqueous system or under solvent-free conditions. Thus, pentachloro phenol was able to be completely dechlorinated within 20 min (Scheme 4.45). This methodology enables a facile route for rapid and complete detoxification of highly toxic polychlorinated aromatic hydrocarbons and environmental remediation71,72. 

From the selectivity point of view, LC-NMR coupling is especially suited to the analysis of compound classes such as nitroaromatics, phenols, aromatic amines, aromatic carboxylic acids, polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and azo- and anthraquinone dyes. Another advantage of LC-NMR coupling for the investigation of aromatic compounds in environmental samples is that the position of substituents on the aromatic ring, e.g. in unknown metabolites or degradation products, can best be determined by NMR spectroscopy. 

Chlorinated aromatic compounds are commonly found as contaminants in environmental soil samples. For example, chlorobenzenes have been listed as priority pollutants and can be found in various matrixes such as water, soils, sediments and sewage sludges. Polychlorinated biphenyls are probable human carcinogens but have been applied in large doses in various industrial products. Analysis of these compounds in solid matrixes, such as soils and sediments, requires several steps. 

Polychlorinated dibenzo-p-dioxins and dibenzofurans are tricyclic aromatic compounds having the following structures ... 

Aromatic compounds are especially stable and are, therefore, important persistent pollutants. They include the polyaromatic hydrocarbons (PAHs), and may be halogenated, such as the polychlorinated biphenyls (PCBs) and many pesticides. Also included are the substituted benzenes, such as phenol. A large body of literature has examined aromatic radiation chemistry [22— 38]. The discussion that follows examines benzene and substituted benzenes as a model for the radiolysis of more complicated aromatic compounds. 

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