Total Petroleum Hydrocarbons Levels Research Articles

Total petroleum hydrocarbon에 의한 작물의 발아 및 유근생장 저해

Abstract BACKGROUND: Total petroleum hydrocarbons (TPH), which are main materials of soil contamination by oil, are a term used for any mixture of hydrocarbons. Korea Ministry of Environment established the maximum permissible level of TPH in farmland by 500 mg/kg, and reported that the TPH level of soil in 266 installation such as gas station, transport company, and military unit ranged from 1, 356 to 55,117 mg/kg and were much higher than the maximum permissible level in 2011. METHODS AND RESULTS: To determine the effect of TPH on crops, we investigated the effect of gasoline, kerosene, and diesel on the germination and radicle growth of mainly consumed crops. The germination rates of control in investigated all crops ranged from 80.0-100%. The germination and radicle growth in majority of investigated crops were not inhibited even at 2,500 mg/L. However, germination in onion, leek, and green perilla and radicle growth in leek, rape, tomato, and green perilla were significantly inhibited by increasing concentrations of gasoline, kerosene and diesel treatment. Germination and radicle growth inhibition of green perilla by kerosene and diesel were the highest, the percent inhibition at the 500 mg/L were 100 and 98.6%, 100 and 88.2%, respectively. 50% inhibition of germination in green perilla by kerosene and diesel were 39.96 and 29.87 mg/L, and 50% inhibition of radicle growth were 52.76 and 177.96 mg/L, respectively.

Quantitative Assessment of Hydrocarbon Contamination in Soil Using Reflectance Spectroscopy: A “Multipath” Approach

Petroleum hydrocarbons are contaminants of great significance. The commonly used analytic method for assessing total petroleum hydrocarbons (TPH) in soil samples is based on extraction with 1,1,2-Trichlorotrifluoroethane (Freon 113), a substance prohibited to use by the Environmental Protection Agency. During the past 20 years, a new quantitative methodology that uses the reflected radiation of solids has been widely adopted. By using this approach, the reflectance radiation across the visible, near infrared-shortwave infrared region (400-2500 nm) is modeled against constituents determined using traditional analytic chemistry methods and then used to predict unknown samples. This technology is environmentally friendly and permits rapid and cost-effective measurements of large numbers of samples. Thus, this method dramatically reduces chemical analytical costs and secondary pollution, enabling a new dimension of environmental monitoring. In this study we adapted this approach and developed effective steps in which hydrocarbon contamination in soils can be determined rapidly, accurately, and cost effectively solely from reflectance spectroscopy. Artificial contaminated samples were analyzed chemically and spectrally to form a database of five soils contaminated with three types of petroleum hydrocarbons (PHCs), creating 15 datasets of 48 samples each at contamination levels of 50-5000 wt% ppm (parts per million). A brute force preprocessing approach was used by combining eight different preprocessing techniques with all possible datasets, resulting in 120 different mutations for each dataset. The brute force was done based on an innovative computing system developed for this study. A new parameter for evaluating model performance scoring (MPS) is proposed based on a combination of several common statistical parameters. The effect of dividing the data into training validation and test sets on modeling accuracy is also discussed. The results of this study clearly show that predicting TPH levels at low concentrations in selected soils at high precision levels is viable. Dividing a dataset into training, validation, and test groups affects the modeling process, and different preprocessing methods, alone or in combination, need to be selected based on soil type and PHC type. MPS was found to be a better parameter for selecting the best performing model than ratio of prediction to deviation, yielding models with the same performance but less complicated and more stable. The use of the "all possibilities" system proved to be mandatory for efficient optimal modeling of reflectance spectroscopy data.

증기추출법과 결합된 공기주입법을 이용한 비수용성액체 해양퇴적물의 TPHs, TCE, PCE 및 BTEX 정화

이 연구는 공기주입법(in-situ air sparging; IAS)이 결합된 증기추출법(vapor extraction; VE)을 이용한 실내 실험 연구로 비수용성액체 유기물(non-aqueous phase liquids; NAPLs)의 총유류계탄화수소(total petroleum hydrocarbons; TPHs), 트리클로에틸렌(trichloroethylene; TCE), 퍼클로로에틸렌(perchloroethylene; PCE), 벤젠(benzene), 톨루엔(toluene), 에틸벤젠(ethylbenzene) 및 크실렌(xylenes)을 제거하기 위한 목적으로 국내 만돌, 하전, 상암, 부산만내 해양 퇴적물들을 대상으로 실험 하였다. 만돌 퇴적물은 사질(sand; S) 특성(평균입도 1.789 <TEX>${\Phi}$</TEX>), 하전은 모래실트(sandy Silt; sZ) 특성(평균입도 5.503 <TEX>${\Phi}$</TEX>) 및 상암은 실트(Silt; Z) 특성(평균입도 5.835 <TEX>${\Phi}$</TEX>)을 나타내었다. 그리고 부산지역 퇴적물은 점토(Clay; C) 특성(평균입도 8.528 <TEX>${\Phi}$</TEX>)을 나타내었다. 48시간 동안 공기를 주입하지 않은 B1 (0 L/min) 컬럼에서 남아있는 TPHs는 만돌, 하전, 상암지역 및 부산지역 샘플퇴적물에서 각각 약 2,459, 6,712, 4,348, 14,279 ppm으로 분석 되었다. 그리고 만돌, 하전, 상암지역 및 부산지역 샘플퇴적물의 B2 (3 L/min)-B5 (5 L/min) 컬럼에서 TCE는 99.5-100.0% 제거되었으며, PCE는 93.2-100.0%까지 제거된 결과를 보였다. 입자크기에 따른 각 성분의 제거량과의 상관관계는 TCE, PCE, toluene, etylbenzene, xylene, BTEX에서 모두 0.90-0.99의 밀접한 상관계수를 보였다. 그러나 TPHs에서는 0.76, Benzene에서는 0.71의 낮은 상관계수를 보였다. This study was carried out in order to determine the remediation of total petroleum hydrocarbons (TPHs), trichloroethylene (TCE), perchloroethylene (PCE), benzene, toluene, ethylbenzene and xylenes (BTEX) compounds for non-aqueous phase liquids (NAPLs) using in-situ air sparging (IAS) / vapor extraction (VE) with the marine sediments of Mandol, Hajeon, Sangam and Busan, South Korea. Surface sediment of Mandol area had sand characteristics (average particle size, 1.789 <TEX>${\Phi}$</TEX>), and sandy silt characteristics (average particle size, 5.503 <TEX>${\Phi}$</TEX>), respectively. Sangam surface sediment had silt characteristics (average particle size, 5.835 <TEX>${\Phi}$</TEX>). Sediment characteristics before experiment in the Busan area showed clay characteristics (average particle size, 8.528 <TEX>${\Phi}$</TEX>). TPHs level in the B1 column of Mandol, Hajeon, Sangam, and Busan sediments were 2,459, 6,712, 4,348, and 14,279 ppm. B2 (3 L/min) to B5 (5 L/min) columns reduced 99.5% to 100.0% of TCE and 93.2% to 100.0% of PCE. Removal rates of TCE, PCE, and BTEX are closely correlated (0.90-0.99) with particle sizes and organic carbon concentrations. However, TPHs (0.76) and benzene (0.71) showed the poorer but moderate correlations with the same parameters.

Bioremediation assessment of diesel–biodiesel-contaminated soil using an alternative bioaugmentation strategy

This study investigated the effectiveness of successive bioaugmentation, conventional bioaugmentation, and biostimulation of biodegradation of B10 in soil. In addition, the structure of the soil microbial community was assessed by polymerase chain reaction-denaturing gradient gel electrophoresis. The consortium was inoculated on the initial and the 11th day of incubation for successive bioaugmentation and only on the initial day for bioaugmentation and conventional bioaugmentation. The experiment was conducted for 32 days. The microbial consortium was identified based on sequencing of 16S rRNA gene and consisted as Pseudomonas aeruginosa, Achromobacter xylosoxidans, and Ochrobactrum intermedium. Nutrient introduction (biostimulation) promoted a positive effect on microbial populations. The results indicate that the edaphic community structure and dynamics were different according to the treatments employed. CO2 evolution demonstrated no significant difference in soil microbial activity between biostimulation and bioaugmentation treatments. The total petroleum hydrocarbon (TPH) analysis indicated a biodegradation level of 35.7 and 32.2 % for the biostimulation and successive bioaugmentation treatments, respectively. Successive bioaugmentation displayed positive effects on biodegradation, with a substantial reduction in TPH levels.

Condition factor, hydrocarbons and bacterial burdens of shellfishes from mudflats in the Qua Iboe Estuary, Nigeria

In this article, the condition factor (CF; health status), bacterial burdens and total petroleum hydrocarbons (TPH) accumulating potential of shellfishes harvested from tidal mudflats in the Qua Iboe Estuary mangrove ecosystem, Nigeria, were investigated. The results revealed that most species of shellfishes from the estuary were not healthy. Tympanotonus fuscatus had a healthy status (CF) of 54.6%, while Mytilis edulis, Thais haemostoma and Callinectes latimanus from hydrocarbon-impacted mudflats exhibited poor health statuses with CF values less than 40%. Though unhealthy, they exhibited great propensity to bioaccumulate hydrocarbons and bacteria including hydrocarbonoclastic bacteria from the environment. The mean levels of TPH in the shellfishes were 4.68 mg/g, 7.92 mg/g, 4.86 mg/g and 3.97 mg/g dry weight of T. fuscatus, M. edulis, Th. haemostoma and C. latimanus, respectively, as against 30.36 mg/g dry weight detected in the intertidal sediment. Correlation between levels of TPH accumulated and CF of the shellfishes (at p < 0.05) revealed weak and not definite relationships in T. fuscatus (r = 0.080), M. edulis (r = 0.102) and Th. haemostoma (r = 0.214), while a positive significant relationship was observed for C. latimanus (r = 0.583). The bacteria densities of freshly collected samples varied between the diverse species of shellfish. The relationship between bacterial load and CF was negative and insignificant in C. latimanus (r = − 0.123) but insignificantly positive in M. edulis (r = 0.011), Th. haemostoma (r = 0.347) and T. fuscatus (r = 0.347). These findings have shown that shellfishes from mudflats in the Qua Iboe Estuary are not healthy but have great capability to bioaccumulate hydrocarbons and bacteria. Their bioaccumulating potential is not definitive and health (CF) dependent, but plausibly determined by the availability and nature of contaminants and their feeding mode. Though the role of oil-degrading bacteria within the viscera of shellfishes is uncertain, it is obvious that the commercially valid species investigated could serve as possible bio-indicators of hydrocarbon and bacterial contaminants in the fishing waters.

Multi-process Bioremediation as an Improved Approach for Petroleum-contaminated Soil Restoration

A multiprocess bioremediation approach was applied to treat petroleum-contaminated soil from Dagang Oilfield, China. The bioremediation processes involved the use of four exogenous microbial strains and six herbage plants screened from a large number of species to remove low levels of total petroleum hydrocarbons (TPH) in contaminated soil. The experimental results indicated that the reduction of TPH increased with the improved community structure from the exogenous petroleum-degrading bacteria by over 35% as compared with that using the indigenous bacterial community. The refreshed microbial consortium was also able to accelerate the reduction of TPH via plant roots (phytoremediation) by over 47%. The TPH reduction rate diminished over time. Molecular biomarker ratios such as Ph/nC17, Pr/nC18 increased during the experiment but the ratio of Pr/Ph decreased. The results suggested that the multi-process bioremediation may significantly shorten the bioremediation duration and can be quite effective for treatment of soils contaminated by lower levels of petroleum.

In situ biosurfactant production and hydrocarbon removal by Pseudomonas putida CB-100 in bioaugmented and biostimulated oil-contaminated soil

In situ biosurfactant (rhamnolipid) production by Pseudomonas putida CB-100 was achieved during a bioaugmented and biostimulated treatment to remove hydrocarbons from aged contaminated soil from oil well drilling operations. Rhamnolipid production and contaminant removal were determined for several treatments of irradiated and non-irradiated soils: nutrient addition (nitrogen and phosphorus), P. putida addition, and addition of both (P. putida and nutrients). The results were compared against a control treatment that consisted of adding only sterilized water to the soils. In treatment with native microorganisms (non-irradiated soils) supplemented with P. putida, the removal of total petroleum hydrocarbons (TPH) was 40.6%, the rhamnolipid production was 1.54 mg/kg, and a surface tension of 64 mN/m was observed as well as a negative correlation (R = −0.54; p < 0.019) between TPH concentration (mg/kg) and surface tension (mN/m), When both bacteria and nutrients were involved, TPH levels were lowered to 33.7%, and biosurfactant production and surface tension were 2.03 mg/kg and 67.3 mN/m, respectively. In irradiated soil treated with P. putida, TPH removal was 24.5% with rhamnolipid generation of 1.79 mg/kg and 65.6 mN/m of surface tension, and a correlation between bacterial growth and biosurfactant production (R = −0.64; p < 0.009) was observed. When the nutrients and P. putida were added, TPH removal was 61.1%, 1.85 mg/kg of biosurfactants were produced, and the surface tension was 55.6 mN/m. In summary, in irradiated and non-irradiated soils, in situ rhamnolipid production by P. putida enhanced TPH decontamination of the soil.

Investigation of Soil and Groundwater Contaminated by Gasoline and Lubricants Around a Railroad Station in S City, Korea

Objective: This research was performed to evaluate the state of oil pollution in an area surrounding a railway station that has over 100 years of business history as a railway station in S City, Korea. The amount of polluted soil was estimated, and the target area for remediation was assessed in this study to restore the oil-polluted area. Methods: To accomplish this aim, five observation wells were installed for the sampling of groundwater, and soil was sampled at 33 points. Electric resistance studies and a trench investigation were undertaken to understand the geological conditions of the site, and the groundwater movement in this area was simulated by MODFLOW. Physiochemical analyses were conducted to determine the quality of the groundwater and the current state of oil pollution influenced by that of the soil. Results: The mean level of total petroleum hydrocarbons (TPHs) in this area was 1,059 mg/kg, and the area for remediation was determined to be 7,610 mg/kg. Levels of benzene, toluene, ethylbenzene, and xylene (BTEX) were determined to be under the legal standard. Conclusion: In terms of depth, the biggest area polluted by TPH found was between 0 and 1 m from ground level, and the affected area was 5,900 <TEX>$m^3$</TEX>. TPHs were not detected in groundwater. Diesel and lubricating oil were the main causes of TPH pollution at this railway station.

Total petroleum hydrocarbon in the tissues of some commercially important fishes of the Bay of Bengal

The present study reports the level of total petroleum hydrocarbon (TPH) in 27 commercially important fish, crustaceans and cephalopods from Orissa coast, Bay of Bengal to provide the baseline data for oil contamination in marine biota. The results showed significant differences in the TPH concentration in different species. Of all fish, Carangoides malabaricus showed the maximum TPH level (av. 13.70μgg−1). In cephalopods, Loligo recorded the maximum TPH (av. 14.87μgg−1) while Metapenaeus dobsoni recorded the maximum TPH (av. 13.18μgg−1) among crustaceans. The concentration of TPH recorded in the present study were higher than the reported values from other studies in Bay of Bengal but were comparable with those of other Indian coast and Gulf water. The species recording maximum concentration and giving significant correlation coefficient may be of interest in oil pollution monitoring and can be used as indicator of hydrocarbon pollution in the region.

Petroleum hydrocarbons and trace metal loads in the mangrove oyster (Crassostrea rhizophorae) from the Qua Iboe Estuary and adjoining creeks in Nigeria

The mangrove oyster Crassostrea rhizophorae was harvested from clutches associated with mangroves in the Qua Iboe Estuary and adjoining creeks to determine the concentrations of total petroleum hydrocarbons (TPH) and trace metals (Fe, Ni, Pb, Cr, V, Cu and Zn) and to understand their bioaccumulation status. The mean concentrations of trace metals in C. rhizophorae were 36.06 mg·kg− 1 for Fe, 0.58 mg·kg− 1 for Ni, 0.05 mg·kg− 1 for Pb, 0.66 mg·kg− 1 for Cr, 0.32 mg·kg− 1 for V, 6.70 mg·kg− 1 for Cu and 3.93 mg·kg− 1 for Zn. The oysters demonstrated relative affinity for accumulation of Fe, Cu and Zn and the relative status of the metals accumulated, in comparison with the background trace metal load, revealed bio-concentration factors of 0.024, 0.016, 0.004, 0.213, 0.037, 0.302 and 0.036 for Fe, Ni, Pb, Cr, V, Cu and Zn, respectively. The concentrations of TPH in the oyster were highly variable and ranged between 6.37 and 8.44 mg·kg− 1 dry weight of C. rhizophorae. Although the correlation between TPH levels in intertidal (epipelic) sediment and oyster specimens was positive (r = 0.097), it was not significant (p>0.05). However, the relationship between TPH and trace metal levels in C. rhizophorae revealed well-fitting linear models that indicated that the trace metals originated from petrogenic sources. Although the levels of TPH and trace metals in the oyster were within permissible levels, they might affect calcium metabolism and the general productivity of the shellfish. The recorded levels are also indicative of long-term and chronic accumulation of hydrocarbons in the estuarine ecosystem and potential risk to human health.

Distribution and characteristics of total petroleum hydrocarbons in Jiuduansha tidal wetland and their potential impact on soil microbial respiration

Microbial respiration is considered to be one of the most sensitive factors in soil; however, it might be altered by soil pollution. To clarify the potential impact of low levels of total petroleum hydrocarbons (TPHs) on soil microbial respiration (SMR) in tidal wetland in Jiuduansha, Shanghai, the distribution and characteristics of TPHs in the typical zones of the Jiuduansha Wetland and nearby watershed were analyzed, and the relationship between soil microbial respiration and TPH was studied. The results showed that the average concentration of TPHs in the soil was 23.98 mg·kg−1, which was a relatively low pollution level. Moreover, the concentration of TPHs in the soil changed significantly with tidal elevation. The main petroleum pollutants in the soil were alkane and aromatic hydrocarbons with less than 10 carbons. The average concentration of TPHs of the surrounding watershed of Jiuduansha was about 0.26 mg·L−1, indicating that it was grade III seawater. The concentration of the inner watershed was higher than that of the outer watershed, indicating that Jiuduansha wetland could enrich TPHs to some extent. Based on the results of regression analysis and a pot experiment, there was a relationship between TPHs and soil microbial respiration. The input of TPHs from the surrounding watershed over long term periods might improve the SMR of the Jiuduansha tidal wetland.

The role of biodegradation in limiting the accumulation of petroleum hydrocarbons in raingarden soils

Previous studies have indicated that raingardens are effective at removing petroleum hydrocarbons from stormwater. There are concerns, however, that petroleum hydrocarbons could accumulate in raingarden soil, potentially resulting in liability for the site owner. In this work, 75 soil samples were collected from 58 raingardens and 4 upland (i.e., control) sites in the Minneapolis, Minnesota area, representing a range of raingarden ages and catchment land uses. Total petroleum hydrocarbon (TPH) concentrations in the samples were quantified, as were 16S rRNA genes for Bacteria and two functional genes that encode for enzymes used in the degradation of petroleum hydrocarbons. TPH levels in all of the raingarden soil samples were low (<3 μg/kg) and not significantly different from one another. The TPH concentration in raingarden soil samples was, however, significantly greater (p ≤ 0.002) than TPH levels in upland sites. In addition, the number of copies of Bacteria 16S rRNA genes and functional genes were greater in the raingardens planted with deeply-rooted natives and cultivars than in raingardens containing simply turf grass or mulch (p < 0.036), suggesting that planted raingardens may be better able to assimilate TPH inputs. The ability of microorganisms present in the soil samples to degrade a representative petroleum hydrocarbon (naphthalene) was also investigated in batch experiments. A sub-set of the field sites was selected for re-sampling, and all soil samples tested (n = 8) were able to mineralize naphthalene. In these experiments the initial mineralization rate correlated with the number of copies of Bacteria 16S rRNA genes present.

Assessment of Bermudagrass Cultivars for Phytoremediation of Petroleum Contaminated Soils

Phytoremediation is an alternative to other technologies for the clean up of petroleum contaminated soil. Ten vegetatively propagated cultivars of bermudagrass were examined for their potential to reduced oil sludge contaminated in soil and select the most efficient cultivar. Soil was mixed with different rates of oil sludge (0, 10, 20, 30, and 40% (w/w) to obtain 0, 2, 4, 6, and 8% total petroleum hydrocarbons(TPHs). Ten cultivars of bermudagrass were planted in pots filled with respected mixtures of soil and sludge. Shoot and root weights and percent reduction in the contamination level were measured after six months. Shoot weight reduced as contamination level increased. The root weight increased up to 6% TPHs level. As contamination level increased, the percent reduction in contamination increased. Reduction was 37.7, 41.0, 35.0, 34.0, 45.0, 41.3, 34.5, 41.3, 34.5, 41.3, 55.0, and 43.6% under Tifdwarf, Tifgreen, Tifway, ISF1, ISF2, JP1, JP2, and Midlawn, 3200W18-4 and 3200W19-9 at the highest contamination level. 3200W18-4 was the most effective cultivar followed by ISF2, 3200W19-9, JP1, and Midlawn, respectively. The results suggested that bermudagrass is an efficient species for phytoremediation of petroleum contaminated soil and the selection for more tolerant and efficient cultivar is possible.

The Potential of Chromolaena Odorata (L) to Decontaminate Used Engine Oil Impacted Soil Under Greenhouse Conditions

This study reports on the use of Chromolaena odorata (L) R.M. King and H. Robinson, an Asteraceae (compositae) and an invasive alien weed in Africa for the remediation of soil contaminated with used engine oil. Used engine oil from a motor service garage was used to artificially contaminate soil taken from a garden to give total petroleum hydrocarbon (TPH) of between 1 and 40 g kg−1. Chromolaena odorata (L), propagated by stem cuttings were transplanted into the contaminated soil and watered just enough to keep the soil at about 70% water holding capacity for 90 day. A set of control experiments containing 40 g kg−1 used engine oil but without plants was set up. All experiments were set up in triplicates. Although the plants in the experiments containing higher than 30 g kg−1 used engine oil showed relatively slower growth (fewer branches and leaves, and shorter in height) compared to those containing lower concentrations, the plants in all the experiments continued to grow until the end of the 90 day period. Residual TPH after 90 days showed that between 21 and 100% of oil was lost from the planted soil while only 11.5% was lost in the control, which did not contain plants during the same period. Analysis of plant tissues showed that both shoot and root tissues contained detectable levels of TPH and selected PAHs were also detectable. Biomass accumulation by Chromolaena odorata was affected adversely by concentrations of oil higher than 20g kg−1. Results of germination rates and germination energy measurements showed that Chromolaena odorata was able to reduce the toxicity of the contaminated soil after 90 days as compared to soils containing freshly contaminated soil.

Biodegradation of petroleum oil achieved by bacteria and nematodes in contaminated water

The treatment of petroleum hydrocarbons from contaminated water by bioremediation via a food chain of microbes is an achievable process. The conversion of fuel oils to biomass derived from microbes has demonstrated that it is an environmentally friendly procedure with no secondary pollution generated. Black petroleum oils with a mean TPH (total petroleum hydrocarbons) concentration of 15,900 mg/L were transformed into a light orange solution with a mean TPH level of 10 mg/L after a bioremediation process of 64 days. A bacterial Bacillus species was identified as the primary degrader for dominating biodegradation of the contaminated materials. Its abundance in turn supported the increase in biomass of a bacterivore nematode. The nematode was introduced successfully from the aeration tank of a sewage treatment plant (STP) to the petroleum contaminated cultures giving its maximum number of 72 individuals/mL. A reduction in the content of TPH was inversely proportional to an increase in bacterial population as well as an abundance of nematode. The cooperation of the microbes promotes the biodegradation rate of the petroleum hydrocarbons.

Bioremediation and reclamation of soil contaminated with petroleum oil hydrocarbons by exogenously seeded bacterial consortium: a pilot-scale study

Spillage of petroleum hydrocarbons causes significant environmental pollution. Bioremediation is an effective process to remediate petroleum oil contaminant from the ecosystem. The aim of the present study was to reclaim a petroleum oil-contaminated soil which was unsuitable for the cultivation of crop plants by using petroleum oil hydrocarbon-degrading microbial consortium. Bacterial consortium consisting of Bacillus subtilis DM-04 and Pseudomonas aeruginosa M and NM strains were seeded to 20% (v/w) petroleum oil-contaminated soil, and bioremediation experiment was carried out for 180days under laboratory condition. The kinetics of hydrocarbon degradation was analyzed using biochemical and gas chromatographic (GC) techniques. The ecotoxicity of the elutriates obtained from petroleum oil-contaminated soil before and post-treatment with microbial consortium was tested on germination and growth of Bengal gram (Cicer aretinum) and green gram (Phaseolus mungo) seeds. Bacterial consortium showed a significant reduction in total petroleum hydrocarbon level in contaminated soil (76% degradation) as compared to the control soil (3.6% degradation) 180days post-inoculation. The GC analysis confirmed that bacterial consortium was more effective in degrading the alkane fraction compared to aromatic fraction of crude petroleum oil hydrocarbons in soil. The nitrogen, sulfur, and oxygen compounds fraction was least degraded. The reclaimed soil supported the germination and growth of crop plants (C. aretinum and P. mungo). In contrast, seeds could not be germinated in petroleum oil-contaminated soil. The present study reinforces the application of bacterial consortium rather than individual bacterium for the effective bioremediation and reclamation of soil contaminated with petroleum oil.

Bacterial communities reflect the spatial variation in pollutant levels in Brazilian mangrove sediment

The majority of oil from oceanic oil spills converges on coastal ecosystems such as mangrove forests. A major challenge to mangrove bioremediation is defining the mangrove's pollution levels and measuring its recuperation from pollution. Bioindicators can provide a welcome tool for defining such recovery. To determine if the microbial profiles reflected variation in the pollutants, samples from different locations within a single mangrove with a history of exposure to oil were chemically characterised, and the microbial populations were evaluated by a comprehensive range of conventional and molecular methods. Multivariate ordination of denaturing gradient gel electrophoresis (DGGE) microbial community fingerprints revealed a pronounced separation between the sediment and rhizosphere samples for all analysed bacterial communities (Bacteria, Betaproteobacteria, Alphaproteobacteria, Actinobacteria and Pseudomonas). A Mantel test revealed significant relationships between the sediment chemical fertility and oil-derived pollutants, most of the bacterial community fingerprints from sediment samples, and the counts by different cultivation strategies. The level of total petroleum hydrocarbons was significantly associated with the Bacteria and Betaproteobacteria fingerprints, whereas anthracene and the total level of polycyclic aromatic hydrocarbons were associated with the Actinobacteria. These results show that microbial communities from the studied mangrove reflect the spatial variation of the chemicals in the sediment, demonstrating the specific influences of oil-derived pollutants.

Distribution and health risk assessment of some organic and inorganic substances in a petroleum facility in central Mexico

An oil distribution and storage station was subjected to an Environmental Auditory and results showed soil contamination in part of the surface. An assessment of the site was required in order to fulfill a complete characterization of the contaminants present in soil and groundwater, as well as to establish the probable sources of contamination. Besides, a health risk assessment was performed to set remediation goals. The aim of this work is to show how the entire characterization and risk assessment process performed in this storage station from central Mexico, regarding to subsoil and groundwater. Thirty sample points were examined. Total petroleum hydrocarbons concentrations in soil were in a very low range (20–268mg/kg). Ethylbenzene, methyl tert-butyl ether, tert-amyl methyl ether, and lead were identified in one sampling point. Iron and zinc were found in all soil samples. There was no correlation between total petroleum hydrocarbons and any of the metals or between both metals. Only two out of four monitoring wells showed total petroleum hydrocarbons levels (1.4 and 66mg/L, respectively). Regarding lead, all four monitored wells showed lead concentrations (0.043–0.15mg/L). Results suggested that metal concentrations were not associated to petroleum contamination, but to iron scrap deposits placed over the soil; nevertheless more data is needed to make a clear conclusion. Health risk assessment showed that none of the evaluated contaminants represented a risk either for the on-site or the off-site receptors, since the hazardous quotients estimated did not exceed the acceptable values.

Biodegradation of semi- and non-volatile petroleum hydrocarbons in aged, contaminated soils from a sub-Arctic site: Laboratory pilot-scale experiments at site temperatures

This study evaluates the feasibility of landfarming biotreatment of petroleum-contaminated soils obtained from a sub-Arctic site at Resolution Island, Nunavut, Canada, and evaluates the changes in composition of the semi- and non-volatile petroleum hydrocarbon fractions during the biotreatment. Pilot-scale landfarming experiments were conducted in a laboratory in soil tanks under temperature profiles representative of the 3-year site air temperatures in July and August where temperature varied uniformly between 1 °C and 10 °C over 10 d. The site soils were acidic and N-deficient, but contained indigenous populations of hydrocarbon-degrading microorganisms. Biostimulation with nitrogen and phosphorus nutrient amendments to achieve C TPH:N:P molar ratio of 100:9:1, and CaCO 3 amendment at 2000 mg Kg −1 for maintaining neutral pH, and periodic 10-day tilling, reduced total petroleum hydrocarbon (TPH) concentrations by up to 64% over a 60-day period. The rate and extent of semi-volatile (F2: >C10–C16) and non-volatile (F3: >C16–C34) petroleum hydrocarbon fractions in the landfarms containing higher initial TPH levels (∼2000 mg Kg −1) and lower TPH levels (∼1000 mg Kg −1) were compared. Significant biodegradation of the F2 and F3 fractions occurred in both of those systems. First-order biodegradation rate constants of up to 0.019 ± 0.001 d −1 were determined for the F3 hydrocarbon fraction and were similar to the F2 fraction biodegradation rate constants of up to 0.024 ± 0.005 d −1. Biodegradation profiles of the C14, C16 and C18 alkanes revealed that at TPH concentrations above 1000 mg Kg −1 these compounds are degraded concurrently, whereas below 1000 mg Kg −1 the higher-molecular weight alkanes are preferentially degraded. After the 60-day treatment period, the TPH concentration was approximately 500 mg Kg −1, and the residual TPH mass was largely associated with particles and aggregated particles with diameters of 0.6–2 mm, rather than the larger or finer particles and aggregates.

Total petroleum hydrocarbon burden in fish tissues from the Arabian Gulf

The levels of total petroleum hydrocarbons (TPH) and lipid contents have been reported for eight commercially important fish species from the Arabian Gulf. GC-FID has been used as quantification technique. Out of the species analyzed, Scarus ghabon showed the highest level of TPH (7.4 ± 3.2 µg g−1) in the muscle tissue followed by Epinephelus tauvina (6.8 ± 3.6 µg g−1). Except for E. microdon (4.8 ± 2.1 µg g−1), all other fish species showed a similar level of TPH concentration. Significant correlations were obtained between lipid contents and TPH levels in the muscles of the fish. Body weight of the fish was also found to be strongly correlated with TPH concentration in the muscle tissue. There is a tendency of accumulating higher TPH in the winter season as compared to in the summer season.