Environmental Fate
Biological. A mixed culture of soil bacteria or a Pseudomonas sp. transformed 1,2,4,5-
tetrachlorobenzene 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, 1,2,4,5-
tetrachlorobenzene 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 (2,4,5-
trichlorophenyl)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), 1,2,3,5-
tetrachlorobenzene (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 Erlenmeyer flask for 28 d yielded 26 ppm heptachlorobiphenyl (Uyeta et al., 1976).
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).
