Potential for Enhancement of Biodegradation of Crude Oil in Louisiana Salt Marshes using Nutrient Amendments

Salt marsh ecosystems in Louisiana are at high risk of an oil contamination event while remediation of these systems is mainly limited to intrinsic bioremediation due to the physical sensitivity of salt marshes. This study investigated both the intrinsic and nutrient enhanced rates of crude oil degradation both in microcosm and core studies. In addition, limiting elements, loading rates and optimum nitrogen forms (NH ₄ ⁺ or NO ₃ ^- ) were determined. Salt marshes have relatively low intrinsic degradation rates (0–3.9% day^-1) of the alkane component (C11-C44) but high rates (8–16% day^-1) of degradation of the polycyclic aromatic hydrocarbon (PAH) fraction (naphthalene, C1, and C2-Naphthalene and Phenanthrene, C1, and C2-Phenanthrene). Additions of nitrogen statistically enhanced degradation of many alkanes and total PAHs while naturally present phosphorous was found to be sufficient. Nitrogen was found to be most effective if applied as NH ₄ ⁺ in the range of 100-500-N mg kg^-1 of soil producing a pore water range of 100-670-N mg L^-1. Core studies indicate that similar trends are observed when applying fertilizers to intact portions of salt marsh.     

Fertilization and Bioaugmentation for Oil Biodegradation in Salt Marsh Mesocosms

The content of 36 elements in the H horizon of coniferous forest floor humus was determined for 56 sampling plots situated in linear transects running out radially to a distance of 14 km from a lead smelter. Fine-scale contour maps of element content in humus revealed five types of basic patterns for the positions of hot spots. Using PCA and contour maps the following four dominant pollution sources were identified that had influenced the accumulation of some elements in humus in the area (615 km²): operation of a lead smelter (Ag, Bi, Cd, Cu, Fe, Hg, In, Pb, S, Sb, Zn), gravel production from stones from uranium pit heaps (Al, Be, Co, Cr, Ga, Mn, Sc, Se, Th, U, V), operation of works processing heat resistant steel (Mo) and anthropogenic or local geogenic factors (Ce, Co, La, Nd, Pr, Y). Except in the case of Pb, Cd, Zn, (As, Hg), high current and long-term accumulated loads of the other elements named above have not previously been indicated in the literature for this area. In addition, no patterns of accumulated elements in humus in details of registers and allotments are known for this area. The interpolated hot spot area for heavy forest humus contamination was found to be 5–80 km², however, U, Cd and Pb were highly accumulated in humus at 100, 320 and more than 630 km², respectively. At a distance of 200 m and 22 km windward and 600 m and 22 km leeward from the lead smelter, the Pb content in the forest floor humus was 78 500 and 131 μg g^-1 windward and 81 050 and 175 μg g^-1 leeward, respectively. The normal Pb content in forest floor humus is less than 100 μg g^-1 in the Czech Republic. Also patterns of accumulated elements in humus in details of registers and allotments have not been known for the area up to now. The distributions of the long-term accumulated elements in humus related to the distance from the source could be described nearly perfectly by exponential equations, while elevation, topography, leeward/windward exposure, and the geology of the sampling plots have not significantly influenced accumulation ofmost elements. Results of the forest floor humus analysis were fully supported by the parallel moss monitoring results. Humus monitoringtechniques can reliably determine the long-term effects of pollutionsources and reveal the hidden accumulated loads of elements in details in the landscape.     

Fertilization and Bioaugmentation for Oil Biodegradation in Salt Marsh Mesocosms

Biodegradation of crude oil is often dependent on the population sizes and metabolic activity of hydrocarbon-degrading microorganisms in addition to nutrient supply. Fertilization with N and P and bioaugmentation of oil-contaminated soil with hydrocarbon-degrading microorganisms may serve to enhance oil biodegradation rates. Glasshouse experiments were conducted to determine the impacts of fertilization and commercial bioremediation products on crude oil biodegradation and on changes in nutrient concentrations and populations of hydrocarbon-degrading microorganisms in salt marsh mesocosms growing Spartina alterniflora. Experiments were conducted under continuously-flooded and alternately-flooded/drained conditions with and without N and P fertilization. MaxBac, a slow-release fertilizer, was applied at a rate of 100 kg N ha^-1 and 20 kg P ha^-1, while additional P was applied at 20 kg P ha^-1. Commercial products failed to enhance total oil or total petroleum hydrocarbon (TPH) degradation under either continuously or alternately-flooded conditions. An average of 62% of TPH was degraded by 33 d under continuously-flooded conditions, while 59% was degraded by 41 d after oil application under alternately-flooded conditions. Products generally did not increase population sizes of heterotrophs orhydrocarbon-degrading microorganisms. Concentrations of NH₄ ⁺ and P decreased during experimentation, and fertilization with N and P stimulated total oil and TPH degradation under continuously-flooded, but not under alternately-flooded conditions.     

Biodegradation of Crude Oil in Contaminated Soils by Free and Immobilized Microorganisms

The efficiencies of free and immobilized bacterial cultures of petroleum hydrocarbon degraders were evaluated and compared in this study.Hydrocarbon-degrading microbial communities with high tolerance to and high degrading ability of crude oil were obtained from the soil contaminated with crude oil in the Yellow River Delta.Then,the microbial cells were immobilized in sodium alginate(SA)beads and sodium alginate-diatomite(SAD)beads.The biodegradation of crude oil in soil by immobilized cells was compared with that by free cells at three inoculation concentrations,1×10⁴ colony forming units(cfu)kg^-1(low concentration,L),5×10⁴ cfu kg^-1(medium concentration,M),and 1×10⁵ cfu kg^-1(high concentration,H).At 20 d after inoculation,the maximum degradation rate in the immobilized systems reached 29.8%(SAD-M),significantly higher(P<0.05)than that of the free cells(21.1%),and the SAD beads showed greater degradation than the SA beads.Moreover,both microbial populations and total microbial activity reached significantly higher level(P<0.05)in the immobilized systems than free cell systems at a same initial inoculation amount.The scanning effectronic microscope(SEM)images also confirmed the advantages of the immobilized microstructure of SAD beads.The enhanced degradation and bacterial growth in the SAD beads indicated the high potential of SAD beads as an effective option for bioremediation of crude oil-contaminated soils in the Yellow River Delta.     

烷基糖苷对石油增溶作用及其影响因素研究

应用生物表面活性剂烷基糖苷在室温下对石油进行增溶,分别考察了溶液pH和无机盐浓度变化对石油溶解效果的影响,并通过正交实验验证确定最佳条件。结果表明,烷基糖苷溶液在浓度超过临界胶束浓度时,表现出明显的增溶特性,其质量增溶比约为0.013;溶液浓度、pH和无机盐浓度变化均能显著影响增溶作用。实验条件下得到烷基糖苷增溶石油的最佳条件为:烷基糖苷浓度39.00 g/L,pH为5,无机盐浓度0.5 mol/L,得到最大溶油量3.99 g/L。     

Enhanced Biodegradation of Used Engine Oil in Soil Amended with Organic Wastes

Three organic wastes (banana skin (BS), brewery spent grain (BSG), and spent mushroom compost (SMC)) were used for bioremediation of soil spiked with used engine oil to determine the potential of these organic wastes in enhancing biodegradation of used oil in soil. The rates of biodegradation of the oil were studied for a period of 84 days under laboratory conditions. Hydrocarbon-utilizing bacterial counts were high in all the organic waste-amended soil ranging between 10.2?×?10⁶ and 80.5?×?10⁶?CFU/g compared to unamended control soil throughout the 84 days of study. Oil-contaminated soil amended with BSG showed the highest reduction in total petroleum hydrocarbon with net loss of 26.76% in 84 days compared to other treatments. First-order kinetic model revealed that BSG was the best of the three organic wastes used with biodegradation rate constant of 0.3163 day^?1 and half-life of 2.19 days. The results obtained demonstrated the potential of organic wastes for oil bioremediation in the order BSG?>?BS?>?SMC.     

Study of Biodegradation Processes of BTEX-ethanol Mixture in Tropical Soil

In Brazil, gasoline is currently blended with ethanol and both compounds may contaminate the environment when spills occur. Ethanol preferential biodegradation delays gasoline degradation in the aquifer, as previously observed; in unsaturated soil a delayed recovery of culturable bacteria and removal of residues in the presence of ethanol suggest a similar situation. This study monitors microbial degrading activity in unsaturated soil with BTEX and BTEX-ethanol mixtures under tropical conditions as well as the effects of bioventing on contaminants degradation. Enzymatic activity was quantified by measuring fluorescein-diacetate hydrolysis by microorganisms, which determines total degrading activity in soil. As microbial enhanced activity may alter soil electromagnetic properties, soil dielectric constant shifts were monitored using Time Domain Reflectometry (TDR), while chemical analyses evaluated contamination residues throughout the experiment. Results suggest that ethanol delays BTEX biodegradation and that bioventing may compensate for this delay by providing oxygen for the continuation of microbial activity. Contamination and bioventing stimulated soil microbiota, while culturable populations were inhibited by contamination, showing soil toxicity. The presence of ethanol caused a higher and longer-lasting boost in enzymatic activity; TDR measurements did not follow these activity shifts, proving not to be an adequate tool for evaluating microbial activity in these experimental conditions. Residual BTEX were detected only in ethanol-containing non-ventilated soils after contamination. The set of results suggests that ethanol could delay BTEX degradation because of its constitutive degradation by soil microbiota, but this effect may be bypassed by bioventing.     

Bioremediation of Petroleum Contaminated Beach Sediments: Use of Crude Palm Oil and Fatty Acids to Enhance Indigenous Biodegradation

Water, Air, &; Soil Pollution - Amendment of simple organic carbon, in the presence of inorganic nutrients, to oil contaminated beach sediments can potentially stimulate the biodegradation of...     

Diagnosis of Nutrient Constraints in Citrus Orchards of Humid Tropical India

ABSTRACT

Citrus growing in humid, tropical India is concentrated in east to northeast India. The region is well known for large-scale commercial cultivation of Citrus reticulata Blanco, cultivar ‘Khasi,’ mandarin. Extensive surveys were conducted covering as many as 108 orchards from 52 locations representing eight states, namely West Bengal, Sikkim, Assam, Meghalaya, Tripura, Mizoram, Arunachal Pradesh, and Manipur. Expressed in milligrams per kilogram, the optimum values for available nutrients in soil were determined to be as: nitrogen (N) (220.8–240.6), phosphorus (P) (21.2–45.6), potassium (K) (252.2–300.8), calcium (Ca) (278.1–318.6), magnesium (Mg) (67.2–92.5), iron (Fe) (82.2–114.6), manganese (Mn) (21.4–32.8), copper (Cu) (0.82–2.62), and zinc (Zn) (2.18–4.22) using multivariate quadratic regression analysis. The corresponding leaf-nutrient values, expressed in percent, were: N (2.23–2.49), P (0.10–0.11), K (1.86–2.12), Ca (2.12–2.32), and Mg (0.28–0.38), and in ppm were Fe (148.2–179.8), Mn (72.2–84.8), Cu (10.4–18.6), and Zn (24.2–38.8). These reference values of soil and leaf analysis were later observed to be well within the range of values obtained for high-performance orchards (45–62 kg tree^?1), confirming the hypothesis that soil fertility and leaf nutrient levels maintained under high yielding orchards could be used provisionally as nutrient diagnostics. Nutrient constraints in the form of N, P, Ca, Mg, Cu, and Zn were identified using these diagnostics, which deserve a place in a fertilizer program of mandarin orchards of the region to obtain sustainable optimum fruit yield.     

Biodegradation of Diesel Oil in Soil by a Microbial Consortium

Biodegradation of diesel oil was performed using adiesel oil-degrading bacterial consortium, in bothlaboratory and pilot scale experiments. The bacterialconsortium was prepared in liquid for laboratory testsand for pilot scale experiments, it was prepared intwo steps, liquid and then in soil. The concentrationof diesel in soil treated with the bacterialconsortium was reduced to <15% of the initialconcentration, within a period of five weeks in bothlaboratory (135 to 19.32 g diesel kg (soil dryweight)^-1) and pilot scale (118 to 17.5 g dieselkg (soil dry weight)^-1) experiments, incomparison with controls (without bacterialconsortium), in which initial concentration of dieselwas reduced by only 5 and 15%, respectively. Dieselbiodegradation rate with the bacterial consortium was2.13 g diesel kg (soil dry weight)^-1 d^-1, itwas slightly enhanced by the addition ofNH₄NO₃ in the presence of bacterialconsortium 2.78 g diesel kg (soil dry weight)^-1d^-1. The enhancement of the microbial activity inhydrocarbon-contaminated soil can be achieved with thecombination of stepwise soil inoculation and nutrient additions.     

Nutrient Uptake and Use Efficiency of Dry Bean in Tropical Lowland Soil

Dry bean is an important source of protein for the population of South America, and yield of this legume is very low in this continent. Knowledge of nutrient uptake and use efficiency of a crop is fundamental to improve yield. A greenhouse experiment was conducted to evaluate growth, nutrient uptake, and use efficiency of dry bean (Phaseolus vulgaris L., cv. BRS Valente) during the growth cycle. Plant samples were collected at 15, 30, 45, 60, 73, and 94 days after sowing. Root dry weight, maximum root length, shoot dry weight, and number of trifoliates were significantly increased in a quadratic fashion with the advancement of plant age. Root dry weight and number of trifoliates had significant positive association with shoot dry weight. Uptake of nutrients in the grain was in the order of nitrogen (N) > potassium (K) > calcium (Ca) > magnesium (Mg) > phosphorus (P) > iron (Fe) > manganese (Mn) > zinc (Zn) > copper (Cu). Hence, it can be concluded the N requirements for bean is greatest and Cu is minimal compared to other essential nutrients for grain yield. Uptake efficiency for root, shoot, and grain production was in the order of P > Mg > Ca > K > N > Cu > Zn > Mn > Fe. The greatest P-use efficiency among macro- and micronutrients can be considered a positive aspect of mineral nutrition of bean, because recovery efficiency of P in acidic Inceptsols is less than 20%.     

营养元素对微囊藻毒素好氧生物降解的影响

通过室内模拟实验,研究了好氧条件下MCLR在太湖沉积物-水体系中的生物降解过程,着重探讨了外加碳源、不同形态的氮源和磷源对该过程的影响。结果表明,好氧条件下沉积物中MCLR经过8 d明显的迟滞期,于第16 d降解到检测限以下,说明太湖沉积物中的土著微生物具有降解MCLR的能力。外加氨氮、硝氮和碳源对MCLR的降解速率均没有显著影响（P≥0.05）,而外加溶解性磷源可显著促进MCLR的降解（P〈0.01）,说明在天然水体沉积物中,磷可能是MCLR好氧降解过程的限制性营养元素。这一结果对于正确评价水体中MC的微生物降解能力以及准确预测MC的浓度变化趋势具有指导意义。     

青岛盐碱地盲管排盐与绿化改造技术的研究

为适应经济社会的快速发展,青岛市加大了对沿海滩涂地的开发利用,对盐碱地绿化改造的技术措施的需求也愈来愈迫切。在对山东省、天津市等地盐碱地改造措施调研考察的基础上,结合青岛市滨海海涂地的实际情况设计出盲管排盐和隔盐层相结合加客土置换的土工改造措施,盲管与排水系统相接,达到排水排盐作用。在工程排盐的同时,应用不同的绿化改造技术,筛选耐盐碱植物树种,施用改良肥、苗木的栽植方式等,可有效地减少地面水分的蒸发,降低地下水位,并抑制盐碱的上移和积累,形成良好的生态循环。     

Bioremediation of a Crude Oil-Polluted Soil: Biodegradation,Leaching and Toxicity Assessments

The combined fate and effects of hydrocarbons (HC) on a soilecosystem affected by bioremediation were studied during 480days in a field experiment. The HC removal rates, the HC andmetabolites mobility and the potential toxicity were assessed.A clayey soil polluted by 18 000 mg HC kg^-1 dry soil, wastreated with either static-ventilated biopile or series of fivewindrows periodically tilled in order to determine the relativeinfluence of nutrients, bulking agents, aeration and soiltemperature. HC concentrations were determined by infraredspectrometry, gravimetry, gas chromatography andthermodesorption. Between 70 to 81% of the initial HC wereremoved through biological processes in fertilized soils,whereas natural attenuation without added nutrients was 56%.When adding fertilizers, residual HC were cyclic compoundspoorly biodegraded and strongly trapped on the organo-mineralmatter. Leaching of HC and water-soluble metabolites wasdemonstrated during the first stages of biodegradation. Lowlevels of the HC were detected in the leachates at day 480.Maximal toxicity was highest immediately after the introductionof oil then decreased as biodegradation proceeded. No toxiceffect was recorded on worms survival and on seeds germinationat day 480. However growth of plants was reduced in treatedsoils and a potential residual toxicity was observed on thebasis of photosynthesis inhibition and bacterial bioluminescence (Microtox) tests.     

Enhanced Biodegradation of Naphthalene and Anthracene by Modified Vermiculite Mixed with Soil

Hydrophobic modified vermiculite mixed with soil was investigated in biodegradation experiments of naphthalene and anthracene. The experiments had been carried out on mixtures of soil and vermiculite at a proportion of 2%, 10%, and 15% and also in the absence of clay used for control. Biodegradation of the pollutants was followed by the decline of naphthalene and anthracene concentration, measured by CG. Compound mineralization was also proved by the evolution of CO₂. The results showed that in the mixture with a higher proportion of vermiculite biodegradation is enhanced compared to that performed in the absence of vermiculite. In general, when vermiculite proportions are increased, the rate of degradation increases, which may account for the bioavailability of compounds. Bioavailability is an important factor for the degradation of compounds with low solubility. Comparison of biodegradation rates shows that naphthalene is degraded faster than anthracene. The chemical structure could be responsible for this observation. However, although we did not identify the microorganism that was in the soil, we can conclude that vermiculite could be an alternative for the bioavailability of such compounds. Vermiculite in the modified form could also be very useful as a barrier to retain organic pollutants in accidental spills.     

Mineralisation of Weathered Crude Oil by a Hydrocarbonoclastic Consortia in Marine Mesocosms

Marine waters are most vulnerable to crude oil pollution due to increased sea-based oil-related activities. Successful remediation of such polluted environments is normally carried out in a laboratory with suitable physical and environmental alterations. However, it is challenging to alter the physical and environmental conditions in crude oil-contaminated natural environments. In a previous study, six hydrocarbonoclastic bacteria were isolated from an oil-contaminated site. Here we report on their ability to mineralise weathered crude oil as a carbon source in seawater mesocosms, in order to construct a hydrocarbonoclastic consortia for the effective mineralisation of hydrocarbons present in the weathered crude oil at seawater-based environment. This was completed without altering the physical and environmental parameters (salinity, pH and temperature) and followed by the detection of microbial community changes. The total amount of oil mineralised by these six isolates individually over 28-day incubation ranged from 4.7 to 10?%. The bacterial consortia composed of these six strains showed a greater mineralisation rate (18.5?%). Temperature gradient gel electrophoresis revealed that the functionally dominant species were present after the first week (week 2 to week 4) following the addition of the consortia, which were represented in dendrogram by cluster 2 and also these weeks representing a distinct point on the Pareto?CLorenz curve; no community could be identified in controls in which no consortia were added. This shows that the addition of consortia potentially dealt with changing environmental conditions and preserved its functionality followed by effective mineralisation of weathered crude oil.     

西部原油成品油管道工程水土保持监测

介绍了西部原油成品油管道工程基本情况及项目区水土流失特点。针对管道工程建设施工及其引发的水土流失的特点,采用全面普查和重点监测相结合的方法,选择技术上可操作性强、经济上可行的监测方式,对不同地貌类型区、不同扰动类型区实施全面到位的监测,准确地反映了该工程建设过程中引发的水土流失状况、水土保持措施的实施情况及其防治效果。     

Growth,Nutrient Uptake,and Use Efficiency in Dry Bean in Tropical Upland Soil

Dry bean (Phaseolus vulgaris L., cv. ‘BRS Requinte’) is an important legume crop and nutrient availability is one of the most yields limiting factors for bean production in tropical upland soils. A greenhouse experiment was conducted in Brazilian Oxisol to study growth, nutrient uptake, and use efficiency of macro- and micronutrients during growth cycle of bean plant. Plants were harvested at 15, 30, 45, 60, 73, and 99 days after sowing for determination of growth parameters and uptake of nutrients. Root dry weight, shoot dry weight and leaf trifoliate increased significantly (P< 0.01) in a quadratic fashion with the advancement of plant age. However, root-shoot ratio decreased significantly with increasing plant age. Concentrations of nitrogen (N), calcium (Ca), magnesium (Mg), and zinc (Zn) decreased with the advancement of plant age. However, concentrations of phosphorus (P), potassium (K), copper (Cu), and manganese (Mn) increased significantly with the advancement of plant age. Accumulation of macro- and micronutrients significantly increased with the increasing plant age. Accumulation of N, P, K and Cu was higher in the grain compared with root and shoot, indicating relatively higher importance of these nutrients in improving grain yield of dry bean. Nitrogen, P and Cu use efficiency was higher for shoot weight compared to grain weight. For grain production, nutrient use efficiency was in the order of Mg > Ca > P > K > N for macronutrients and Cu > Zn = Mn for micronutrients.     

不同种植年限日光温室土壤盐分和养分变化研究

以山西省临汾市不同种植年限的蔬菜日光温室土壤为研究对象，分析了土壤有机质、碱解氮、硝态氮、速效磷、速效钾等养分指标的累积状况以及温室土壤电导率、可溶性盐、pH值的变化情况。结果表明，与大田土壤相比，温室土壤电导率和可溶性盐含量逐年增加，pH值下降，种植8a的日光温室土壤盐分累积量已接近黄瓜的生育障碍临界点；土壤养分均有不同程度的累积，尤其是土壤速效磷、硝态氮的累积严重；日光温室特殊的环境条件以及过量施用化肥是土壤盐分累积和养分富集的主要原因。     

Vegetative Response of Sagittaria Lancifolia to Burning of Applied Crude Oil

Field studies were conducted to evaluate Sagittarialancifolia sensitivity to in-situ burning of appliedcrude oil. Twenty-four plots were constructed (2.4 × 2.4× 0.6 m) in a fresh marsh and experimental treatmentswere: 1) control (no oiling and/or burning); 2) oiling (naturalremediation); and 3) oiling plus burning. South Louisiana Crudewas applied at 2 L m^-2, with a garden sprayer, on Sagittaria lancifolia stems and leaves of the oiling andoiling/burning treatment plots. Two marsh burns were conducted,one in August (Site A) and a second on separate plotsthe following April (Site B) to compare seasonal effects ofoiling and burning. Burning was initiated three days after oilapplication when the marsh was flooded to a 15–25 cm depth andwinds were calm. Live stem count, plant height growth and carbonfixation were measured up to 9 times over 52 weeks after thefirst burn (August) and 6 times over 19 weeks after the secondin-situ burn (April). Aboveground biomass was measured atthe conclusion of each study. Oil application and oil burninghad short term effects on Sagittaria lancifoliavegetation. Five to six weeks after each burn, measured Sagittaria lancifolia vegetative parameters in control, oiledand oiled/burned plots were not significantly different. Onlybiomass clipped 20 weeks after the April burn showed significanttreatment differences. Under our experimental conditions, datasuggests leaving oil to degrade and the marsh to recovernaturally may be an option to consider. Plant recovery inoiled/burned plots was as rapid as oiled plant recovery. Thissuggests burning may be a viable remediation method if a rapidresponse is needed to remove oil and control oil migration tosensitive areas.