Organic compounds, chlorination sources

SW-846, is used to measure emissions of semivolatile principal organic constituents. Method 0010 is designed to determine destruction and removal efficiency (DRE) of POHCs from incineration systems. The method involves a modification of the EPA Method 5 sampling train and may be used to determine particulate emission rates from stationary sources. The method is applied to semivolatile compounds, including polychlorinated biphenyls (PCBs), chlorinated dibenzodioxins and dibenzofurans, polycyclic organic matter, and other semivolatile organic compounds. 

Purification of drinking water, by adding CI2 to kill bacteria, is a source of electrophilic chlorine and contributes a nonenzymatic pathway for a chlorination and subsequent chloroform formation. Although some of the odor associated with tap water may be due to chloroform, more of it probably results from chlorination of algae-produced organic compounds. 

Identify the extent and source(s) of DNAPLs and other organic compounds (e.g., chlorinated solvents, pesticides, etc.) ... 

Such processes lead to the formation of adsorbable halogenated organic compounds (AOX) in high concentrations. Typical concentrations found in a continuous antifelt treatment are shown in Table 4. The high dissolved organic carbon (DOC) determined in the baths is one of the sources for the formation of high concentrations of chlorinated compounds. The formation of chlorinated products is the result of chemical reactions directly with the fiber, with organic compounds released from the fibers, and with added auxiliaries. 

Chlorine isotope studies have been applied to understand the environmental chemistry of anthropogenic organic compounds, such as chlorinated organic solvents or biphenyls. The primary goal of such studies is to identify and quantify sources and... 

The EPA has conducted four major studies of actual human exposure using monitors worn by random samples of people. The results are shocking. Smoking, clothes that had been dry cleaned and hung in closets, and heated water in showers and clothes washers (i.e., chloroform from chlorinated water) are major sources of human exposure to volatile organic compounds (VOCs), all of which exceeded outdoor exposure sources by two to five times at the median exposure level. The major sources of exposure to another VOC, p-dichlorobenzene, are toilet fresheners and mothballs. Pesticide exposure stems from two main sources (1) vapors emitted by soil into homes through basements and (2) soil tracked into buildings on shoes. Major stationary and mobile sources account for only 2 to 25 percent of personal exposure to the two dozen or so VOCs and pesticides that the EPA studied (Wallace 1993, 138 Ott and Roberts 1998). 

Second, reaction 8.9 and other relevant reactions appear to occur preferentially on available solid surfaces, which are often ice crystals but may also be particles of sulfate hazes from volcanic eruptions or human activity. Third, volatile bromine compounds are even more effective (via Br atoms) than chlorine sources at destroying ozone methyl bromide is released into the atmosphere naturally by forest fires and the oceans, but anthropogenic sources include the use of organic bromides as soil fumigants (methyl bromide, ethylene dibromide) and bromofluorocarbons as fire extinguishers (halons such as CFsBr, CF2BrCl, and C2F4Br2). 

Chlorinated aliphatic compounds are globally distributed. Natural product organohalides such as chloromethane and chloramphenicol are probably produced in diverse soil environments. Many halogenated organic compounds are biosynthesized by marine organisms (Neidleman Geigert, 1986), so the oceans area source as well. 

More than 100 organochlorines have been identified and structurally characterized in the laboratory chlorination of terrestrial humic acid, although the major products are chloroform and trichloroacetic acid, followed by dichloroacetic acid and chlorinated C-4 dicarboxylic acids (324). In addition, other products that form in the chlorination of both humic acid and the model compound 3,4-dihydroxybenzoic acid are shown in Scheme 3.11. A more recently discovered source of natural organically bound chlorine is peat, reaching to 0.2% of the dry weight, and estimated to have accumulated globally to the extent of 280-1,000 million tons (169). 

Dechlorination occurred in parts of the soil column where reducing conditions (Eh-pH conditions) are dominant. The most significant reductive dechlorination of TCE occurred near the cathode, a source of electrons during electroosmosis. Results show the need to include a decay term in the transport equations. The results show that potential chemical transformation of chlorinated organic compounds could enhance the remediation efficiency during EO. 

The feasibility of applying solar radiation as a source of UV-visible radiation has made the photo-Fenton system an economical and competitive process. Within this context an alternative method has been developed based on solar photocatalytic oxidation and natural processes of wastewater treatment [5], as well as sunlight-driven degradations of many compounds, such as EDTA [30], phenols [7,13], pesticides [31-33], surfactants [34], diclofenac [24], formic acid [22], azo-dyes [19], non-biodegradable chlorinated solvents [35], nitroaniline [16], and other organic compounds [21, 36]. 

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