Centre for Environmental Sustainability and Remediation, School of Applied Sciences, RMIT University, Melbourne, VIC, 3083, Australia.
Environ Sci Pollut Res Int. 2015 Oct;22(19):14809-19. doi: 10.1007/s11356-015-4624-2. Epub 2015 May 21.
Diesel represents a common environmental contaminant as a result of operation, storage, and transportation accidents. The bioremediation of diesel in a contaminated soil is seen as an environmentally safe approach to treat contaminated land. The effectiveness of the remediation process is usually assessed by the degradation of the total petroleum hydrocarbon (TPH) concentration, without considering ecotoxicological effects. The aim of this study was to assess the efficacy of two bioremediation strategies in terms of reduction in TPH concentration together with ecotoxicity indices and changes in the bacterial diversity assessed using PCR-denaturing gradient gel electrophoresis (DGGE). The biostimulation strategy resulted in a 90 % reduction in the TPH concentration versus 78 % reduction from the natural attenuation strategy over 12 weeks incubation in a laboratory mesocosm-containing diesel-contaminated soil. In contrast, the reduction in the ecotoxicity resulting from the natural attenuation treatment using the Microtox and earthworm toxicity assays was more than double the reduction resulting from the biostimulation treatment (45 and 20 % reduction, respectively). The biostimulated treatment involved the addition of nitrogen and phosphorus in order to stimulate the microorganisms by creating an optimal C:N:P molar ratio. An increased concentration of ammonium and phosphate was detected in the biostimulated soil compared with the naturally attenuated samples before and after the remediation process. Furthermore, through PCR-DGGE, significant changes in the bacterial community were observed as a consequence of adding the nutrients together with the diesel (biostimulation), resulting in the formation of distinctly different bacterial communities in the soil subjected to the two strategies used in this study. These findings indicate the suitability of both bioremediation approaches in treating hydrocarbon-contaminated soil, particularly biostimulation. Although biostimulation represents a commercially viable bioremediation technology for use in diesel-contaminated soils, further research is required to determine the ecotoxicological impacts of the intervention.
柴油是由于操作、储存和运输事故而成为常见的环境污染物。在受污染的土壤中进行生物修复被视为一种处理污染土地的环境安全方法。修复过程的有效性通常通过总石油烃(TPH)浓度的降解来评估,而不考虑生态毒性效应。本研究的目的是评估两种生物修复策略在减少 TPH 浓度方面的效果,同时评估使用 PCR-变性梯度凝胶电泳(DGGE)评估的生态毒性指数和细菌多样性变化。在实验室中含有柴油污染土壤的中观模型中孵育 12 周后,生物刺激策略导致 TPH 浓度降低了 90%,而自然衰减策略则降低了 78%。相比之下,自然衰减处理使用 Microtox 和蚯蚓毒性测定法导致的生态毒性降低幅度是生物刺激处理的两倍多(分别为 45%和 20%)。生物刺激处理涉及添加氮和磷,通过创建最佳 C:N:P 摩尔比来刺激微生物。与修复前后的自然衰减样品相比,生物刺激土壤中的铵和磷酸盐浓度增加。此外,通过 PCR-DGGE,由于添加了营养物质和柴油(生物刺激),观察到细菌群落发生了显著变化,导致两种策略下土壤中形成了截然不同的细菌群落。这些发现表明,这两种生物修复方法都适用于处理含烃污染土壤,特别是生物刺激。尽管生物刺激代表了一种在柴油污染土壤中使用的商业可行的生物修复技术,但仍需要进一步研究来确定干预的生态毒性影响。