Byard J L
Toxicology Consultant, Incorporated, El Macero, California.
J Toxicol Environ Health. 1987;22(4):381-403. doi: 10.1080/15287398709531081.
Reports of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzo-furans (PCDFs) in human tissues were reviewed to assess their toxicological significance. The predominance of 2,3,7,8-chlorinated congeners in human tissues and in the food chain, but not in other environmental matrices, suggests that the food chain is the major source of human residues. Exposures to unique distributions of congeners can result in recognizable patterns of excess 2,3,7,8-chlorinated PCDDs/PCDFs in humans. Current levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) in the general population can be accounted for by an average level of 133 or 27 ppq (parts per quadrillion) in food based on an estimated half-life in humans of 1 or 5 yr, respectively. 2,3,7,8-TCDD is more persistent in humans than in rodents or lagomorphs, resulting in higher body burdens in humans at comparable levels in the diet. Taken alone, this toxicokinetic difference would increase risks estimated for humans from toxicity in laboratory animals. However, humans appear to be less susceptible due to the following: less food is ingested per body mass, more 2,3,7,8-TCDD is sequestered in adipose tissue and away from target organs, and tissue susceptibility appears to be lower than in the most sensitive rodents and lagomorphs. The body burden of 2,3,7,8-TCDD in a Seveso woman receiving an apparently nontoxic dose was approximately 180 times the average body burden of 2,3,7,8-TCDD equivalents in the general population of industralized societies. The body burden of prisoners who were exposed dermally to a suspension of 2,3,7,8-TCDD and who developed severe chloracne was estimated to be as much as 38 times that of the Seveso woman. These comparisons suggest a considerable margin of safety for the general population.
对人体组织中多氯代二苯并 - 对二噁英（PCDDs）和多氯代二苯并呋喃（PCDFs）的报告进行了审查，以评估它们的毒理学意义。人体组织和食物链中以2,3,7,8 - 氯代同系物为主，但在其他环境基质中并非如此，这表明食物链是人体残留的主要来源。接触独特的同系物分布会导致人体中出现可识别的过量2,3,7,8 - 氯代PCDDs/PCDFs模式。基于人体中分别估计为1年或5年的半衰期，一般人群中当前的2,3,7,8 - 四氯二苯并 - 对二噁英（2,3,7,8 - TCDD）水平可以由食物中平均133或27 ppq（万亿分之一）的水平来解释。2,3,7,8 - TCDD在人体中的持久性高于啮齿动物或兔形目动物，在饮食水平相当的情况下，人体中的体内负荷更高。单独来看，这种毒代动力学差异会增加根据实验动物毒性估计的人体风险。然而，由于以下原因，人类似乎不太敏感：每单位体重摄入的食物较少，更多的2,3,7,8 - TCDD被隔离在脂肪组织中远离靶器官，并且组织敏感性似乎低于最敏感的啮齿动物和兔形目动物。在塞韦索一名接受明显无毒剂量的女性中，2,3,7,8 - TCDD的体内负荷约为工业化社会普通人群中2,3,7,8 - TCDD当量平均体内负荷的180倍。经皮肤接触2,3,7,8 - TCDD悬浮液并患严重氯痤疮的囚犯体内负荷估计高达塞韦索女性的38倍。这些比较表明普通人群有相当大的安全边际。
