Ghiorse W C, Herrick J B, Sandoli R L, Madsen E L
Section of Microbiology, Cornell University, Ithaca, New York 14853-8101, USA.
Environ Health Perspect. 1995 Jun;103 Suppl 5(Suppl 5):107-11. doi: 10.1289/ehp.95103s4107.
Microbial activity patterns at buried coal-tar disposal sites have been under investigation for several years to determine the response of naturally occurring microflora to polycyclic aromatic hydrocarbons (PAHs) at the sites. At one site in upstate New York, data have shown enrichment of PAH-degrading bacteria in subsurface contaminated zones but not in uncontaminated zones. Similar work at a midwestern site showed that the same trends existed in a heterogeneous disposal site except that a borehole outside the plume showed some PAH-mineralization activity. Polymerase chain reaction amplification of DNA extracted from sediment samples from the New York site indicated the presence of naphthalene metabolism genes nahAc and nahR, similar to those found on the NAH7 plasmid of Pseudomonas putida G7. Significant sequence polymorphism was observed in amplified nahAc products, indicating that divergent homologs of nahAc were present in the native community. Protozoan numbers were elevated in sediment samples displaying relatively high PAH-degrading activity, suggesting that a food chain was established based on PAH-degrading bacteria. Removal of the coal-tar source at the site occurred in 1991. In 1992, sampling of three key borehole stations revealed that mixing and backfilling operations had introduced soil microorganisms into the source area and introduced 14C-PAH-mineralization activity into the previously inactive pristine area. Thus removal of the source of the contaminants and restoration at the site have altered the microbial activity patterns outside the contaminant plume as well as in the source area.
多年来，一直在对埋藏煤焦油处置场的微生物活动模式进行调查，以确定天然存在的微生物群落对处置场中多环芳烃（PAHs）的反应。在纽约州北部的一个场地，数据显示在地下污染区域存在PAH降解细菌的富集，但在未受污染区域则没有。在中西部一个场地开展的类似工作表明，在一个异质处置场也存在相同趋势，只是羽流外的一个钻孔显示出一些PAH矿化活性。对从纽约场地沉积物样本中提取的DNA进行聚合酶链反应扩增，表明存在萘代谢基因nahAc和nahR，与恶臭假单胞菌G7的NAH7质粒上发现的那些基因相似。在扩增的nahAc产物中观察到显著的序列多态性，表明在原生群落中存在nahAc的不同同源物。在显示出相对较高PAH降解活性的沉积物样本中，原生动物数量有所增加，这表明基于PAH降解细菌建立了食物链。该场地的煤焦油源于1991年被清除。1992年，对三个关键钻孔站点进行采样发现，混合和回填作业将土壤微生物引入了源区，并将14C-PAH矿化活性引入了之前未活跃的原始区域。因此，污染物源的清除和场地的修复改变了污染物羽流外以及源区的微生物活动模式。
