Boyd Stephen A, Sallach J Brett, Zhang Yingjie, Crawford Robert, Li Hui, Johnston Cliff T, Teppen Brian J, Kaminski Norbert E
Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, Michigan, USA.
Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA.
Environ Toxicol Chem. 2017 Oct;36(10):2671-2678. doi: 10.1002/etc.3815. Epub 2017 Jun 15.
The effectiveness of activated carbon in reducing the bioavailability of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was examined from the context of using in situ sorbent amendments to remediate soils/sediments contaminated with polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs). This technology has gained rapid acceptance based on observations that activated carbon amendments predictably lower PCDD/F concentrations in water and bioaccumulation by simple aquatic organisms and earthworms; it has been assumed that bioavailability to mammals is similarly reduced, although this has been disproven for other sorbent materials. In the present study TCDD was absorbed to a microporous activated carbon (TCDD-AC) using the incipient wetness method. An aqueous suspension of TCDD-AC and an equivalent dosage of TCDD in corn oil were administered by oral gavage to B6C3F1 mice. The relative bioavailability of TCDD-AC was determined by quantifying and comparing the hepatic induction of cyp1A1 (messenger ribonucleic acid) and suppression of the immunoglobulin M antibody-forming cell immune response by the 2 forms of TCDD. A concentration-dependent response was observed for both assays when TCDD in corn oil was administered to mice. However, when equivalent masses of TCDD were administered as TCDD-AC, no induction of cyp1A1 or suppression of the immunoglobulin M antibody-forming cell response was observed. The absence of these 2 sensitive aryl hydrocarbon receptor-mediated responses in mice provides the first direct evidence that activated carbon can sequester TCDD in a form that eliminates its bioavailability to mammals. These results support the premise that activated carbon can be used to reduce the bioeffective dose of TCDD delivered to mammals and that activated carbon amendments may provide a low-cost alternative to traditional remediation technologies. Environ Toxicol Chem 2017;36:2671-2678. © 2017 SETAC.
从使用原位吸附剂改良剂修复受多氯二苯并对二恶英/二苯并呋喃（PCDD/Fs）污染的土壤/沉积物的角度出发，研究了活性炭在降低2,3,7,8-四氯二苯并对二恶英（TCDD）生物有效性方面的效果。基于活性炭改良剂可预测地降低水中PCDD/F浓度以及简单水生生物和蚯蚓对其生物累积的观察结果，该技术已迅速得到认可；尽管其他吸附剂材料并非如此，但人们一直认为对哺乳动物的生物有效性也会同样降低。在本研究中，采用初湿含浸法将TCDD吸附到微孔活性炭（TCDD-AC）上。通过经口灌胃将TCDD-AC的水悬浮液和等量剂量的玉米油中的TCDD给予B6C3F1小鼠。通过定量和比较两种形式的TCDD对cyp1A1（信使核糖核酸）的肝脏诱导作用以及免疫球蛋白M抗体形成细胞免疫反应的抑制作用，来确定TCDD-AC的相对生物有效性。当给小鼠施用玉米油中的TCDD时，两种测定均观察到浓度依赖性反应。然而，当以TCDD-AC形式施用等量质量的TCDD时，未观察到cyp1A1的诱导或免疫球蛋白M抗体形成细胞反应的抑制。小鼠中这两种敏感的芳烃受体介导反应的缺失提供了首个直接证据，即活性炭可以以消除其对哺乳动物生物有效性的形式螯合TCDD。这些结果支持了这样一个前提，即活性炭可用于降低传递给哺乳动物的TCDD的生物有效剂量，并且活性炭改良剂可能为传统修复技术提供一种低成本的替代方案。《环境毒理学与化学》2017年；36:2671 - 2678。© 2017 SETAC。
