DISPOSITION OF HALOGENATED DIBENZOFURANS

氯化二苯并对二恶英(CDDS)和二苯并呋喃(CDF)是 在世界范围内被发现为环境污染物。他们不知道 工业用途，但在合成和分解过程中产生 其他氯化有机化学品。他们已经参与了 在几起人体中毒事件中。溴化二恶英和 呋喃还涉嫌构成职业和 环境危害。溴化萘，一类与之相关的 化合物，卷入了一起人与动物的事件 在过去的十年里投毒。卤化程度 与这些化合物的毒性有关，与那些 具有少于四个卤素的同系物是相对非的 有毒的。需要在四个侧位进行卤化 毒性，然后随着卤素数量的增加而趋于减少 增加。这些化学物质的新陈代谢是一种解毒 进程。坚持不懈会增加身体负担 反复低剂量暴露。而口服吸收相当好。 (&gt；70%)，皮肤吸收往往有限。然而，随着剂量的增加 向环境中存在的水平下降 在某些情况下，所用剂量的40%-50%可能被吸收 穿透皮肤。单次涂抹后，继续吸收。 以缓慢的速度持续了几天。2，3，7，8-四氢呋喃(TCDF) 代谢相对较快，被吸收得比 相关化合物，2，3，4，7，8-五CDF，1，2，3，7，8-五CDF，或 2，3，7，8-四氯甲烷(TCDD)。1，2，3，7，-五CDF的处置是 在雄性大鼠身上进行了检测。这一异构体分布在 身体(肝脏和脂肪是主要的组织储存库)，以及 在粪便中消除，半衰期为2天。新陈代谢 发生在胆汁排泄之前。这些结果类似于 通过TCDF获得的，但与研究得出的结果相反 对于代谢都很差的2，3，4，7，8-五CDF和TCDD， 因此也是坚持不懈的。

Chlorinated dibenzo-p-dioxins (CDDs) and dibenzofurans (CDFs) are found worldwide as environmental pollutants. They have no known industrial use but are produced during the synthesis and breakdown of other chlorinated organic chemicals. They have been involved in several incidents of human poisoning. Brominated dioxins and furans are also suspected of posing an occupational and environmental hazard. Brominated napthalenes, a related group of compounds, were involved in an incident of human and animal poisoning in the past decade. The degree of halogenation correlates with the toxicity of these compounds, with those congeners possessing less than four halogens being relatively non- toxic. Halogenation in the four lateral positions is required for toxicity which then tends to decrease as the number of halogens increases. Metabolism of these chemicals is a detoxification process. Persistence can result in increasing body burdens upon repeated low dose exposures. While oral absorption is quite good (>70%), dermal absorption tends to be limited. However, as doses are decreased towards the levels which exist in environmental situations, as much as 40-50% of the applied dose may be absorbed through the skin. After a single application, absorption continued for several days at a slow rate. 2,3,7,8-TetraCDF (TCDF), which is metabolized relatively rapidly, was better absorbed than the related compounds, 2,3,4,7,8-pentaCDF, 1,2,3,7,8-pentaCDF, or 2,3,7,8-tetraCDD (TCDD). The disposition of 1,2,3,7,-pentaCDF was examined in male rats. This isomer was distributed throughout the body (liver and adipose were the major tissue depots), and eliminated in the feces with a half-life of 2 days. Metabolism occurred prior to biliary excretion. These results are similar to those obtained with TCDF but are in contrast to those from studies with 2,3,4,7,8-pentaCDF and TCDD which are both poorly metabolized, and therefore persistent.