Harrad Stuart, Ren Jianzhang, Hazrati Sadegh, Robson Matthew
Division of Environmental Health and Risk Management, Public Health Building, School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, United Kingdom.
Chemosphere. 2006 May;63(8):1368-76. doi: 10.1016/j.chemosphere.2005.09.027. Epub 2005 Nov 9.
Chiral signatures of PCB#s 95 and 149 are reported for indoor air, grass, omnivorous and vegan duplicate human diet homogenates, and human faeces. Comparison of chiral signatures of both congeners in grass with those reported previously for outdoor air (measured at a height of 1.5 m) and soil at the same location suggest that volatilisation of PCBs present in soil may exert a significant influence on concentrations in grass. Duplicate diet homogenates display racemic signatures for both congeners. Alongside the racemic signatures in both outdoor and indoor air, this implies that human intake via diet and inhalation is racemic, and that the previously observed variation between individuals in the extent of enantioselective degradation in human liver samples indicates possible inter-individual variation in ability to metabolise PCBs. Chiral signatures of PCB# 95 in the 10 human faecal samples analysed indicate 8 to be racemic, but 2 to display an excess of the 2nd eluting enantiomer. This is consistent with the excess of the 1st eluting enantiomer reported elsewhere for human liver samples, as it implies enantioselective excretion of the 2nd eluting enantiomer. However, the racemic residues for PCB# 95 in the majority of faecal samples are a possible indication that enantioselective interaction of chiral PCBs with cytochrome P450 occurs slowly. The racemic or near-racemic signatures observed for PCB# 95 and 149 in indoor air match closely those in outdoor air, but differ from those in soil, adding to the weight of evidence that ventilation of indoor air is a far more significant contributor to outdoor air concentrations than volatilisation of PCBs from soil.
报告了室内空气、草、杂食和素食重复人类饮食匀浆以及人类粪便中多氯联苯95和149的手性特征。将草中这两种同系物的手性特征与先前在同一地点测量的室外空气（在1.5米高度处）和土壤中的特征进行比较，表明土壤中存在的多氯联苯挥发可能对草中的浓度产生重大影响。重复饮食匀浆显示两种同系物均为外消旋特征。除了室外和室内空气中的外消旋特征外，这意味着通过饮食和吸入的人类摄入量是外消旋的，并且先前在人类肝脏样本中观察到的对映体选择性降解程度的个体差异表明个体间代谢多氯联苯的能力可能存在差异。分析的10份人类粪便样本中多氯联苯95的手性特征表明，8份为外消旋，但2份显示第二种洗脱对映体过量。这与其他地方报道的人类肝脏样本中第一种洗脱对映体过量一致，因为这意味着第二种洗脱对映体的对映体选择性排泄。然而，大多数粪便样本中多氯联苯95的外消旋残留物可能表明手性多氯联苯与细胞色素P450的对映体选择性相互作用发生缓慢。在室内空气中观察到的多氯联苯95和149的外消旋或近外消旋特征与室外空气中的特征非常匹配，但与土壤中的特征不同，这进一步证明了室内空气通风对室外空气浓度的贡献远大于多氯联苯从土壤中的挥发。
