PCB-1242

Pavlou, 1978) 277 µg/L at 20 °C (Murphy et al., 1987) 16 ppb (quoted, Watanabe et al., 1985) 703 µg/L at 23 °C (Lee et al., 1979) Vapor density: 10.67 g/L at 25 °C, 9.01 (air = 1) Vapor pressure (x 10-4 mmHg): 2.5 at 20 °C (Murphy et al., 1987) 4.06 at 25 °C (quoted, Mackay and Wolkoff, 1973) 5.74 at 25 °C (estimated using GC retention data, Foreman and Bidleman, 1985) 10 at 37.8 °C (calculated, Monsanto, 1960) Environmental fate: Biological. A strain of Alcaligenes eutrophus degraded 81% of the congeners by dechlorination under anaerobic conditions (Bedard et al., 1987). A bacterial culture isolated from Hamilton Harbour, Ontario was capable of degrading a commercial mixture of PCB-1242. The metabolites identified by GC/MS included isohexane, isooctane, ethylbenzene, isoheptane, isopropylbenzene, n-propylbenzene, isobutylbenzene, n-butylbenzene, and isononane (Kaiser and Wong, 1974). A strain of Pseudomonas, isolated from activated sludge and grown with biphenyl as the sole carbon source, degraded 2,4′-dichlorobiphenyl yielding the following compounds: two monochlorobenzoic acids, two monohydroxydichlorobiphenyls, and a yellow hydroxyoxo(chlorophenyl)chlorohexadienoic acid. Irradiation of the mixture containing these compounds led to the formation of two monochloroacetophenones and the disappearance of the yellow compound. Similar compounds were found when 2,4′-dichlorobiphenyl was replaced with a PCB-1242 mixture (Baxter and Sutherland, 1984). Reported degradation products by the microorganism Alcaligenes BM-2 for a mixture of polychlorinated biphenyls include monohydroxychlorobiphenyl, 2-hydroxy-6-oxochloro-phenylhexa-2,4-dieonic acid, chlorobenzoic acid, chlorobenzoylpropionic acid, chlorophenylacetic acid, and 3-chlorophenyl-2-chloropropenic acid (Yagi and Sudo, 1980). When PCB-1242 was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum, no significant biodegradation was observed. At a concentration of 5 mg/L, percent losses after 7, 14, 21, and 28-d incubation periods were 37, 41, 47, and 66, respectively. At a concentration of 10 mg/L, only 34, 33, 15, and 0% losses were observed after

The white rot fungus Phanerochaete chrysosporium degraded the majority of congeners in PCB-1242 under ligninolytic (low-N) and under nonligninolytic (high-N) media. Degradation was more extensive in a malt extract media. The percent decrease by weight in total congeners for PCB-1242 ranged from 56.3 to 60.9 %. All congeners were degraded extensively regardless of the number of chlorines at the ortho, meta, and para positions indicating nonspecificity for the position of chlorine atoms (Yadav et al., 1995). Soil. In Hudson River, NY sediments, the presence of adsorbed PCB-1242 in core samples suggests it is very persistent in this environment. The estimated half-life ranged from 1.3 to 2.1 yr (Bopp et al., 1982). Photolytic. PCB-1242 in a 90% acetonitrile/water solution containing 0.2 to 0.3 M sodium borohydride and irradiated with UV light (λ = 254 nm) reacted to yield dechlorinated biphenyls. Without sodium borohydride, the reaction proceeded much more slowly (Epling et al., 1988). Chemical/Physical. When PCB-1242-contaminated sand was treated with a poly(ethylene glycol)/potassium hydroxide mixture at room temperature, 27% reacted after 2 wk forming aryl poly(ethylene glycols) (Brunelle and Singleton, 1985). Trstenjak and Perdih (1999) reported that the fungus Phanerochaete chrysosporium removed the majority of PCB-1242 from a saturated water solution at room temperature up to a volumetric ratio of one to several thousand. In static column tests containing pelletized Phanerochaete chrysosporium, the percentage of PCB-1242 not removed ranged from 2.4 to 12% at pellets to contaminated water ratios of 1:5,000 and 1:500,000, respectively. When exposed to fire, black soot containing PCBs, polychlorinated dibenzofurans, and chlorinated dibenzo-p-dioxins is formed (NIOSH, 1997). PCB-1242 will not hydrolyze to any reasonable extent (Kollig, 1993). Mackay and Wolkoff (1973) estimated an evaporation half-life of 5.96 h from a surface water body that is 25 °C and 1 m deep. Exposure limits: Potential occupational carcinogen. NIOSH REL: TWA 1.0 g/m3, IDLH 5 mg/m3; OSHA PEL: TWA 1 mg/m3; ACGIH TLV: TWA 1 mg/m3 (adopted). Toxicity: LC50 (7-d) for Macromia sp. 800 µg/L, Orconectes nais 30 µg/L (Johnson and Finley, 1980). LC50 (7-d) for bluegill sunfish 125 µg/L, rainbow trout 67 µg/L (Johnson and Finley, 1980). LC50 (96-h) for Gammarus pseudolimnaeus 10 µg/L, Ischnura venticalis 400 µg/L, cutthroat trout 5,420 µg/L, channel catfish >100 µg/L, yellow perch >150 µg/L (Johnson and Finley, 1980). Acute oral LD50 for rats 4,250 mg/kg (quoted, RTECS, 1985). Drinking water standard (final): For all PCBs, the MCLG and MCL are zero and 0.5 µg/L, respectively (U.S. EPA, 2000). Uses: Dielectric liquids; in fixed paper capacitors; heat-transfer liquid widely used in transformers and utility transmission lines; swelling agents for transmission seals; ingredient in lubricants, oils, and greases; plasticizers for cellulose products, vinyl, and chlorinated rubbers; in polyvinyl acetate to improve fiber-tear properties. In fluorescent and high-intensity discharge ballasts manufactured prior to 1979 (U.S. EPA, 1998) and in electric motors (Monsanto, 1960). Prior to being banned in 1976, PCB-1254 was used in home appliances including air conditioners, furnaces, washers, and driers. May have been added to automotive transmission oils to swell shrunken transmission seals in place (Monsanto, 1960). At a concentration of 5 to 25 wt %, increased the effective kill-life of the lindane spray up to 10 times. May have been used in chlordane and BHC insecticide formulations. In polyvinyl acetate emsulsions to impart strong bonding power in adhesives. In various nitrocellulose lacquers to

contain tricresyl phosphate (Monsanto, 1960).