In situ microbial and phytoremediation of crude oil contaminated soil by Cynodon sp.

Crude oil contamination of land and water leads to their abandonment after heavy oil recovery processes. Analogous to bioremediation, phytoremediation has provided an efficient solution towards land reclamation through enhancement of flora. The present work manifests significance of phytoremediation via reclamation of crude oil contaminated soil collected from Kalol, India. The collected soil was analyzed for pH, oxidation–reduction potential, electrical conductivity (EC), bulk density, particle size, moisture. The experimental work consists three batch units; pot A, pot B and pot C with crude oil contaminated soil, fresh soil and control respectively. While observing plant growth for 120 days, Total Petroleum Hydrocarbon (TPH) was measured at determined intervals for estimation of percentage degradation. After 90 days of pot observation, contaminated soil was inoculated with rhizospheric bacterial inoculum developed from pot A which forms new batch for microbial-remediation as an additional scope to this work. Gas chromatography mass spectroscopy (GC-MS-MS) was carried out for determination of naphthalene contamination. Crude oil degradation in pot A was estimated as 82.16% followed with the affirmation given by degradation kinetics whereas, 60.68% and 36.75% degradation was observed in pot C-control and new batch respectively. Cynodon sp. grown in pot A was confirmed by identification as reported. Statement of novelty This work signifies the potential of phytoremediation by Cynodon sp. grown in crude oil contaminated soil fertilized with cow dung and corn silk. Although studies in this context are present in literature, this study adds an affirmation to it. Also it differs in terms of contamination percentage removal which is better compared to previous studies but the only demerit is that specific specie could not be identified due to time limitation. Also, the use of corn silk as fertilizer is new to literature. Indigenous microorganisms vary based on substrates and conditions and this experiment was performed on sweet crude oil extracted from Gujarat, India which adds new information to the literature.

陆地与水体遭受原油污染后，会在重油开采工序完成后被废弃。与生物修复（bioremediation）类似，植物修复（phytoremediation）通过强化植物群落，为土地复垦提供了高效可行的解决方案。本研究阐明了针对印度卡洛（Kalol）地区采集的原油污染土壤开展植物修复复垦的重要意义。研究人员对采集的土壤样本开展了多项指标分析，包括pH值、氧化还原电位、电导率（electrical conductivity, EC）、容重、粒径分布及含水率。本实验设置3个批次培养盆钵：A组、B组与C组，分别装填原油污染土壤、新鲜洁净土壤与空白对照样本。在为期120天的植物生长观测周期内，研究人员于预设时间节点测定总石油烃（Total Petroleum Hydrocarbon, TPH）含量，以估算原油降解率。盆钵观测进行至90天时，研究人员向污染土壤中接种源自A组盆钵的根际细菌接种剂，由此形成新的微生物修复批次，为本研究拓展了额外的研究方向。采用气相色谱-串联质谱（gas chromatography mass spectroscopy-MS, GC-MS-MS）技术测定萘类污染物含量。A组盆钵的原油降解率经测算为82.16%，降解动力学分析进一步验证了该结果；C组空白对照与新微生物修复批次的降解率分别为60.68%与36.75%。本研究中A组盆钵种植的狗牙根属（Cynodon sp.）植物经形态鉴定已得到确认。本研究的创新之处在于：证实了以牛粪与玉米须作为肥料，在原油污染土壤中种植狗牙根属植物的植物修复潜力。尽管该研究领域已有相关文献报道，但本研究为其提供了进一步的实证支撑。此外，本研究的污染物去除率优于既往同类研究，这是本研究的显著优势；但受限于实验时间，未能明确该狗牙根属物种的具体分类，这是本研究的一处不足。同时，将玉米须作为肥料应用于原油污染土壤修复场景，在现有学术文献中尚属首次。本土微生物的群落组成会随基质类型与环境条件的不同而发生变化，本实验采用的是从印度古吉拉特邦（Gujarat）采集的低硫原油，这一实验设计为现有相关研究补充了新的实验数据。