ABSTRACT

Hammers et al., 1982) 4.604 at 25 °C (shake flask-GLC, de Bruijn et al., 1989) 4.51 (generator column-GC, Miller et al., 1984; generator column, Doucette and Andren, 1988) 4.70 (Chiou, 1985; shake flask-GC, Pereira et al., 1988) Solubility in organics: Soluble in benzene, chloroform, and ether (Weast, 1986) Solubility in water: 10.9 µmol/L at 25 °C (generator column-GC, Miller et al., 1984) 2.2 mg/L at 25 °C (shake flask-GC, Boyd et al., 1998) 0.56 mg/L at 20-25 °C (Kim and Saleh, 1990) 0.6 mg/L (Geyer et al., 1980) 0.465 mg/L at 25 °C (shake flask-HPLC, Banerjee, 1984) 2.75 µmol/L at 25 °C (shake flask-UV spectrophotometry, Yalkowsky et al., 1979) 208, 322, 528, 739, and 1,127 µg/L at 5, 15, 25, 35, and 45 °C, respectively (generator column-

GC, Shiu et al., 1997) 543 µg/L at 27 °C (shake flask-GC, Shiu et al., 1997) Vapor pressure (x 10-3 mmHg): 5 at 25 °C (extrapolated, Mackay et al., 1982) Environmental fate: Biological. A mixed culture of soil bacteria or a Pseudomonas sp. transformed 1,2,4,5tetrachlorobenzene to 2,3,5,6-tetrachlorophenol (Ballschiter and Scholz, 1980). After incubation in sewage sludge for 32 d under anaerobic conditions, 1,2,4,5-tetrachlorobenzene did not biodegrade (Kirk et al., 1989). In an enrichment culture derived from a contaminated site in Bayou d’Inde, LA, 1,2,4,5tetrachlorobenzene underwent reductive dechlorination to 1,2,4-trichlorobenzene. The maximum dechlorination rate, based on the recommended Michaelis-Menten model, was 5.5 nM/d (Pavlostathis and Prytula, 2000). Photolytic. Irradiation (λ ≥285 nm) of 1,2,4,5-tetrachlorobenzene (1.1-1.2 mM/L) in an acetonitrile-water mixture containing acetone (0.553 mM) as a sensitizer gave the following products (% yield): 1,2,4-trichlorobenzene (25.3), 1,3-dichlorobenzene (8.1), 1,4-dichlorobenzene (3.6), 2,2′,3,4′,5,5′,6-heptachlorobiphenyl (4.19), four hexachlorobiphenyls (6.78), four pentachlorobiphenyls (2.33), one tetrachlorobiphenyl (0.32), 2,4,5-trichloroacetophenone, and (2,4,5trichlorophenyl)acetonitrile (Choudhry and Hutzinger, 1984). Without acetone, the identified photolysis products (% yield) included 1,2,4-trichlorobenzene (27.7), 1,3-dichlorobenzene (0.3), 1,4-dichlorobenzene (8.5), pentachlorobenzene (trace), 1,2,3,4-tetrachlorobenzene (0.45), 1,2,3,5tetrachlorobenzene (1.11), 2,2′,3,4′,5,5′,6-heptahlorobiphenyl (1.24), three hexachlorobiphenyls (1.19), and four pentachlorobiphenyls (0.56) (Choudhry and Hutzinger, 1984). The sunlight irradiation of 1,2,4,5-tetrachlorobenzene (20 g) in a 100-mL borosilicate glass-stoppered

When an aqueous solution containing 1,2,4,5-tetrachlorobenzene and a nonionic surfactant micelle (Brij 58, a polyoxyethylene cetyl ether) was illuminated by a photoreactor equipped with 253.7-nm monochromatic UV lamps, no photoisomerization was observed. However, based on photodechlorination of other polychlorobenzenes under similar conditions, it was suggested that tri-and dichlorobenzenes, chlorobenzene, benzene, phenol, hydrogen, and chloride ions are likely to form. The half-life for this reaction, based on the first-order photodecomposition rate of 1.88 x 10-3/sec, is 6.1 min (Chu and Jafvert, 1994). Chemical/Physical. Based on an assumed base-mediated 1% disappearance after 16 d at 85 °C and pH 9.70 (pH 11.26 at °C), the hydrolysis half-life was estimated to be >900 yr (Ellington et al., 1988). Toxicity: EC50 (48-h) for Pseudokirchneriella subcapitata 0.44 mg/L (Hsieh et al., 2006). LC50 (14-d) for Poecilia reticulata 304 µg/L (Könemann, 1981). LC50 (96-h) for bluegill sunfish 1.6 mg/L (Spehar et al., 1982), Cyprinodon variegatus 900 ppb using natural seawater (Heitmuller et al., 1981). LC50 (72-h) for Cyprinodon variegatus 800 ppb (Heitmuller et al., 1981). LC50 (48-h) for Daphnia magna >530 mg/L (LeBlanc, 1980), Cyprinodon variegatus 900 ppb (Heitmuller et al., 1981). LC50 (24-h) for Daphnia magna >530 mg/L (LeBlanc, 1980), Cyprinodon variegatus >1.8 ppm (Heitmuller et al., 1981). Acute oral LD50 for rats 1,500 mg/kg, mice 1,035 mg/kg (quoted, RTECS, 1985). Heitmuller et al. (1981) reported a NOEC of 300 ppb. Uses: Insecticides; intermediate for herbicides and defoliants; electrical insulation; impregnant for moisture resistance.