3,4,3 ,4 -Tetrachlorobiphenyl

In the rabbit, the nonplanar PCB 2,2, 5,5 -tetrachlorobiphenyl (2,2, 5,5 -TCB) is converted into the 3, 4 -epoxide by monooxygenase attack on the meta-para position, and rearrangement yields two monohydroxymetabolites with substitution in the meta and para positions (Sundstrom et al. 1976). The epoxide is also transformed into a dihydrodiol by epoxide hydrolase attack (see Chapter 2, Section 2.3.2.4). This latter conversion is inhibited by 3,3,3-trichloropropene-l,2-oxide (TCPO), thus providing strong confirmatory evidence for the formation of an unstable epoxide in the primary oxidative attack (Forgue et al. 1980). 

Several stndies have related the structures of PCBs to their rates of elimination by mammals. In one stndy (Mizutani et al. 1977), the elimination of tetrachlorobiphenyl... 

Mizutani, T., Hidaka, K., Ohe, T., and Matsumoto, M. (1977). A comparative study on accumulation and elimination of tetrachlorobiphenyl isomers in mice. Bulletin of Environmental Contamination and Toxicology 18, 452-461. 

The formation of 3,3, 4,4 -tetrachloroazobenzene, l,3-bis(3,4-dichlorophenyl)triazine and 3,3, 4,4 -tetrachlorobiphenyl from 3,4-dichloroaniline and nitrate by E. coli plausibly involved intermediate chemical formation of the diazonium compound by reaction of the amine with nitrite (Corke et al. 1979) (Figure 2.2g). 

An anaerobic sediment sample was incubated with 2,3,4,6-tetrachlorobiphenyl at various temperatures between 4 and 66°C (Wu et al. 1997a). The main products were 2,4,6- and... 

Wu Q, DL Bedard, J Wiegel (1997a) Effect of incubation temperature on the route of microbial reductive dechlorination of 2,3,4,6-tetrachlorobiphenyl in polychlorinated biphenyl (PCB)-contaminated and PCB-free freshwater sediments. Appl Environ Microbiol 63 2836-2843. 

Cutter L, KR Sowers, HD May (1998) Microbial dechlorination of 2,3,5,6-tetrachlorobiphenyl under anaerobic conditions in the absence of soil or sediment. Appl Environ Microbiol 64 2966-2969. 

Holoman TRP, MA Elberson, LA Cutter, HD May, KR Sowers (1998) Characterization of a defined 2,3,5,6-tetrachlorobiphenyl-orffio-dechlorinating microbial community by comparative seqnence analysis of genes coding for 16S xRLihAppl Environ Microbiol 64 3359-3367. 

An anaerobic bacterial enrichment cnltnre was used to examine the dechlorination of 2,3,4,5-tetrachlorobiphenyl that prodnced 2,3,5-trichlorobiphenyl exclusively. Although there was no alteration in the valnes of 5 C, compound-specific analysis of Arochlor 1268 showed that there was a trend for decreasing C abundance with increasing content of chlorine. This is consistent with dechlorination of the congeners with more chlorine substituents. 

An anaerobic sediment sample was incnbated with 2,3,4,6-tetrachlorobiphenyl at various temperatures between 4 and 66°C (Wn et al. 1997). The main products were 2,4,6- and 2,3,6-trichlorobiphenyl and 2,6-dichlorobiphenyl the first of these was produced maximally and discontinnonsly at 12 and 34°C, the second maximally at 18°C, and the third was dominant from 25 to 30°C. Dechlorination was not observed above 37°C. 

Macdonald RW, WJ Cretney, N Crewe, D Patou (1992) A history of octachlorodibenzo-/ -dioxin, 2,3,7,8-tetrachlorodibenzofuran, and 3,3, 4,4 -tetrachlorobiphenyl contamination in Howe Sound, British Columbia. Environ Sci Technol 26 1544-1550. 

As previously discussed according to Henry s Law, as water solubility decreases and vapor pressure increases volatility will increase. Therefore a chemical like tetrachlorobiphenyl will have a... 

Bott, T.L., Standley, L.J. (2000) Transfer of benzo[a]pyrene and 2,2,5,5,-tetrachlorobiphenyl from bacteria and algae to sediment-associated freshwater invertebrates. Environ. Sci. Technol. 34, 4936 -942. 

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