Kannan N, Tanabe S, Tatsukawa R
Department of Environment Conservation, Ehime University, Matsuyama, Japan.
Arch Environ Health. 1988 Jan-Feb;43(1):11-4. doi: 10.1080/00039896.1988.9934366.
The non-ortho chlorine substituted coplanar polychlorinated biphenyls (PCBs), namely, 3,3',4,4'-tetra-(T4CB), 3,3'4,4',5-penta-(P5CB), and 3,3',4,4',5,5', hexachlorobiphenyl (H6CB) are found to be the most toxic congeners of PCBs eliciting toxic and biological responses typical of 2,3,7,8-tetrachloro dibenzo-p-dioxin (T4CDD). Analyses of human adipose tissues for these congeners revealed 94-860 pg/g of T4CB, 120-730 pg/g of P5CB, and 36-200 pg/g of H6CB on wet weight basis. These were significantly higher than 2,3,7,8-T4CDD detected in the same samples (less than 1-18 pg/g). On the basis of in vitro and in vivo induction of hepatic microsomal benzo(a)pyrene hydroxylase (AHH) and ethoxyresorufin O-deethylase (EROD), "T4CDD toxic equivalents" were calculated for coplanar PCBs in humans. "T4CDD toxic equivalent" for 3,3',4,4',5-P5CB was one order of magnitude higher than 2,3,7,8-T4CDD. Considering the extreme toxic potential and persistence of coplanar PCBs, their presence in the human body may pose a greater toxic threat than dioxins and dibenzofurans.
非邻位氯取代的共平面多氯联苯（PCBs），即3,3',4,4'-四氯联苯（T4CB）、3,3',4,4',5-五氯联苯（P5CB）和3,3',4,4',5,5'-六氯联苯（H6CB），被发现是多氯联苯中毒性最强的同系物，会引发典型的2,3,7,8-四氯二苯并对二恶英（T4CDD）的毒性和生物学反应。对人体脂肪组织中这些同系物的分析显示，以湿重计，T4CB的含量为94 - 860 pg/g，P5CB为120 - 730 pg/g，H6CB为36 - 200 pg/g。这些含量显著高于在相同样本中检测到的2,3,7,8-T4CDD（低于1 - 18 pg/g）。基于体外和体内对肝微粒体苯并(a)芘羟化酶（AHH）和乙氧基异吩恶唑酮O-脱乙基酶（EROD）的诱导作用，计算了人体中共平面多氯联苯的“T4CDD毒性当量”。3,3',4,4',5-P5CB的“T4CDD毒性当量”比2,3,7,8-T4CDD高一个数量级。考虑到共平面多氯联苯的极端毒性潜力和持久性，它们在人体中的存在可能比二恶英和二苯并呋喃构成更大的毒性威胁。
