Laboratory Design Criteria for Monitoring Biostimulated Bioremediation of a Crude Oil Contaminated Soil in Niger Delta Using Total Petroleum Hydrocarbon

The remediation of crude oil-impacted soil has always been a challenge in different soil environments and climatic conditions. Bioremediation technology has offered a breakthrough in restoring crude oil-impacted soil/sediment in muddy, dry soil and wetlands. Though, there have been varied environmental conditions that have hampered the success of the bioremediation process. This study has evaluated the effectiveness of a biostimulated bioremediation of crude oil-impacted soil using some design criteria—nutrient amendment (NPK fertilizer) and moisture content. Soil sample sets—A, B, C, D, E, F, and G were impacted with crude oil at a ratio of 10 g/kg and amended with varying amounts of nutrient 30, 60, and 80 g of N.P.K fertilizer. The medium for the inoculation of the nutrient was water and the volume of water applied varied from 30% to 80% saturation. The soil sample sets were harvested at an interval of 3 months for 180 days to determine the concentration of total petroleum hydrocarbon left in the soil. The analysis of the total petroleum hydrocarbon was achieved using a GC-FID with a capillary column and autosampler. Soil samples were extracted with mixed solvent dichloromethane and acetone at a 1:1 ratio. The total petroleum hydrocarbon results show that biostimulated bioremediation achieved better results in soil sample sets with low moisture content (30% water saturation) and moderate nutrient amendment. The biodegradation of the sample sets with high water saturation and a high nutrient amendment was slow with a higher amount of total hydrocarbon content at the end of the 180 days. The variability in the hydrocarbon degradation pattern of contaminated soil shows that biostimulated bioremediation achieved better results in soils with low moisture content than in soil environments with high water content (saturation). More so, nutrient overdosing of the substrate hampered the effectiveness of the remediation process.

东海近岸石油污染对海洋生物体内石油烃含量的影响

研究了东海区沿岸水域主要海洋生物体内石油烃含量的分布和变化后得出鱼体中的总石油烃含量为1．40－21．84毫克／千克（干重，下同），双壳类的含量范围为13．85－88．63毫克／千克，甲壳类的含量范围为9．37－59．35毫克／千克，头足类的含量范围为5．40－9．06毫克／千克。污染海区与其它海域相比，生物体内总石油烃的含量相差极大。外海采集的鱼类样品平均含量为3．41毫克／千克，而在西沪港下山所采集的鱼类样品的平均含量为17．58毫克／千克。通过分析调查海域中几种主要生物的石油烃富集系数，富集系数最高可达794．3。东海沿岸石油污染主要可能是由船舶排放的含油废水造成的，并且在局部地区污染已相当严重。

烃源岩可溶烃、热解烃、总有机碳含量与光谱指数相关性研究

烃源岩的可溶烃含量(S1)、热解烃含量(S2)和总有机碳含量(TOC)是进行烃源岩研究和评价的重要指标,以往主要通过实验室分析方法获得,时效性得不到保证。为了探讨野外快速测量这些指标的可行性,采集了乌兹别克斯坦克孜勒库姆地块10件烃源岩样品,运用地面ASD光谱仪和碳硫分析仪,分别测定了样品的可见光-近红外-短波红外(Vis-NIR-SWIR)反射光谱和S1, S2和TOC含量参数。运用光谱拟合微分,获得了上述样品反射光谱的一阶导数、二价导数等微分数据;并运用线性回归方程拟合和拟合结果统计分析,研究了这些数据同S1, S2和TOC含量之间的相关性。结果表明:烃源岩S1含量与原始光谱、光谱一阶导数、二阶导数分别有1 973, 511和239个波段相关,相关系数绝对值最大值分别为0.612, 0.823和0.889,相关性程度分别为弱、较强、极强;烃源岩S2含量与原始光谱、光谱一阶导数、二阶导数分别有2, 144和205个波段相关,相关系数绝对值最大值分别为0.561, 0.867和0.926,相关性程度分别为弱、较强、极强;烃源岩TOC含量与原始光谱无相关性,与光谱一阶导数、二阶导数分别有18、 180个波段相关,相关系数绝对值最大值分别为0.882和0.879,相关性都极强。此外, S1含量与光谱二阶导数的2 012 nm波段拟合优度最高,达0.790;S2含量与光谱二阶导数的363 nm波段拟合优度最高,达0.858;TOC含量与光谱一阶导数的2 480 nm波段拟合优度最高,达0.777。结果说明,利用可见光-近红外-短波红外反射光谱反演烃源岩S1, S2和TOC含量具有比较好的效果。为研究野外烃源岩的原位检测奠定了重要的基础。

高浓度石油污染土壤清洗工艺及生物修复实验研究

以高浓度石油污染土壤为研究对象,利用自行研发的清洗剂进行清洗工艺研究,对清洗后的土壤采用生物技术进行修复。结果表明:最佳清洗条件为清洗剂质量分数2%、清洗温度50℃、清洗时间30 min、搅拌速率100r·min^(-1)时,清洗率达到70.9%。在菌剂添加量4%、调理剂添加量1%、有机肥添加量4%和翻堆频次为每月3次的条件下,20周含油率降低至0.96%,降解率达到了84.6%。生物修复后石油烃质量分数(C10~C40)降低至6 290 mg·kg^(-1)。

4种盐生植物生长对土壤石油污染的响应

为了探讨4种新疆盐生植物在石油污染土壤上的生长适应性及修复效果,设置了5种不同浓度的石油污染处理,对4种供试盐生植物的株高、鲜重、根冠比及土壤中总石油烃含量进行了观测。结果表明:①当土壤石油污染浓度为0.5%时,对4种供试植物的生长均有一定的促进作用,其生长指标均大于空白对照组,但差异不显著。②随着污染物浓度的增大,4种供试植物的生长也受到了显著的抑制作用。其中,盐角草与野榆钱菠菜幼苗在生长过程中,当土壤石油污染浓度分别为1.5%和2%时,出现叶片枯黄死亡现象,其生长期只能维持20 d左右。③经过120 d的修复,4种供试植物对土壤中石油烃类污染物都有一定的修复作用,其总石油烃降解率为:鞑靼滨藜﹥盐地碱蓬﹥野榆钱菠菜﹥盐角草。④与其他2种植物相比,鞑靼滨藜和盐地碱蓬具有较大的石油污染耐受性和修复效果,表明其具有修复石油污染土壤的应用潜力。