ABSTRACT
Biological. Reported degradation products by the microorganism Alcaligenes BM-2 for a mixture of polychlorinated biphenyls include monohydroxychlorobiphenyl, 2-hydroxy-6-oxochlorophenylhexa-2,4-dieonic acid, chlorobenzoic acid, chlorobenzoylpropionic acid, chlorophenylacetic acid, and 3-chlorophenyl-2-chloropropenic acid (Yagi and Sudo, 1980). When PCB-1232 was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum for 7 d, significant biodegradation with rapid adaptation was observed (Tabak et al., 1981). Photolytic. PCB-1232 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 more slowly (Epling et al., 1988). Chemical/Physical. Zhang and Rusling (1993) evaluated the bicontinuous microemulsion of surfactant/oil/water as a medium for the dechlorination of polychlorinated biphenyls by electrochemical catalytic reduction. The microemulsion (20 mL) contained didodecyldimethylammonium bromide, dodecane, and water at concentrations of 21, 57, and 22 wt %, respectively. The catalyst used was zinc phthalocyanine (3.5 nM). When PCB-1232 (69 mg), the microemulsion and catalyst were subjected to an electrical current of mA/cm2 on 11.2 cm2 lead electrode for 12 h, a dechlorination yield of >99.8% was achieved. Reaction products included minor amounts of mono-and dichlorobiphenyls (0.01 mg), biphenyl, and reduced alkylbenzene derivatives. PCB-1232 will not hydrolyze to any reasonable extent (Kollig, 1993). At influent concentrations of 1.0, 0.1, 0.01, and 0.001 mg/L, the GAC adsorption capacities were 630, 120, 22, and 4.0 mg/g, respectively (Dobbs and Cohen, 1980). Exposure limits: NIOSH REL: TWA 1.0 µg/m3, IDLH 5 mg/m3. Toxicity: LC50 (96-h) for cutthroat trout 2,500 µg/L (Johnson and Finley, 1980). A teratogen and suspected human carcinogen having a low toxicity (Patnaik, 1992). Acute oral LD50 for rats 4,470 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: In polyvinyl acetate to improve fiber-tear properties; as an insulator fluid for electric condensers and as an additive in very high pressure lubricants. In fluorescent and high-intensity discharge ballasts manufactured prior to 1979 (U.S. EPA, 1998). 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 (Monsanto, 1960).
