Centre for Environmental Sustainability and Remediation, School of Science, RMIT University, Bundoora, VIC, 3083, Australia.
School of Agriculture and Environment, The University of Western Australia, Crawley, WA, 6009, Australia.
Environ Pollut. 2018 Dec;243(Pt A):94-102. doi: 10.1016/j.envpol.2018.08.040. Epub 2018 Aug 18.
The bioremediation of historic industrial contaminated sites is a complex process. Co-contamination, often with lead which was commonly added to gasoline until 16 years ago is one of the biggest challenges affecting the clean-up of these sites. In this study, the effect of heavy metals, as co-contaminant, together with total petroleum hydrocarbons (TPH) is reported, in terms of remaining soil toxicity and the structure of the microbial communities. Contaminated soil samples from a relatively hot and dry climate in Western Australia were collected (n = 27). Analysis of soils showed the presence of both contaminants, TPHs and heavy metals. The Microtox test confirmed that their co-presence elevated the remaining ecotoxicity. Toxicity was correlated with the presence of lead, zinc and TPH (0.893, 0.599 and 0.488), respectively, assessed using Pearson Correlation coefficient factor. Next Generation Sequencing of soil bacterial 16S rRNA, revealed a lack of dominate genera; however, despite the variation in soil type, a few genera including Azospirillum spp. and Conexibacter were present in most soil samples (85% and 82% of all soils, respectively). Likewise, many genera of hydrocarbon-degrading bacteria were identified in all soil samples. Streptomyces spp. was presented in 93% of the samples with abundance between 7% and 40%. In contrast, Acinetobacter spp. was found in only one sample but was a dominant member of (45%) of the microbial community. In addition, some bacterial genera were correlated to the presence of the heavy metals, such as Geodermatophilus spp., Rhodovibrio spp. and Rubrobacter spp. which were correlated with copper, lead and zinc, respectively. This study concludes that TPH and heavy metal co-contamination significantly elevated the associated toxicity. This is an important consideration when carrying out risk assessment associated with natural attenuation. This study also improves knowledge about the dynamics of microbial communities in mixed contamination scenarios.
历史工业污染场地的生物修复是一个复杂的过程。共污染是一个最大的挑战之一，尤其是在过去 16 年里，铅被普遍添加到汽油中。在这项研究中，报告了重金属作为共污染物与总石油烃（TPH）一起对这些场地的清理的影响，包括剩余土壤毒性和微生物群落的结构。从澳大利亚西部一个相对炎热干燥的气候中采集了受污染的土壤样本（n=27）。土壤分析表明存在两种污染物，TPH 和重金属。Microtox 测试证实，它们的共同存在提高了剩余的生态毒性。毒性与铅、锌和 TPH 的存在相关（Pearson 相关系数因子分别为 0.893、0.599 和 0.488）。土壤细菌 16S rRNA 的下一代测序显示，缺乏主导属；然而，尽管土壤类型存在差异，但少数属，包括 Azospirillum spp. 和 Conexibacter，存在于大多数土壤样本中（分别为 85%和 82%的所有土壤）。同样，在所有土壤样本中都鉴定出了许多烃类降解细菌的属。Streptomyces spp. 出现在 93%的样本中，丰度在 7%至 40%之间。相比之下，Acinetobacter spp. 仅在一个样本中发现，但却是微生物群落（45%）的主要成员。此外，一些细菌属与重金属的存在相关，如 Geodermatophilus spp.、Rhodovibrio spp. 和 Rubrobacter spp.，它们分别与铜、铅和锌相关。本研究得出结论，TPH 和重金属的共污染显著提高了相关毒性。这是在进行与自然衰减相关的风险评估时需要考虑的一个重要因素。本研究还提高了对混合污染情况下微生物群落动态的认识。
