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Results for “Soil bioremediation”

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At least 19 recordsLinked to original sources

PubMed2001

[An off site petroleum-contaminated soil bioremediation technology: soil compositing in windrow].

With off-site bioremediation technology, a soil contaminated by crude oil from Liaohe Oil Field was treated on a 20 x 10 m prepared bed. 8 composting windrow units were set, each measured 8 m in length, 2 m in width, and 0.35 m in height. The results showed that when the pollutant petroleum hydrocarbon(TPH) was within the range of 4.16-7.72 g.100 g-1 soil, the total degradation rate of TPH reached 45.19%-56.74% after 53 days operation, which indicated that a technological basis would be provided for the bioremediation of oil-contaminated soil.

Biodegradation, Environmental↗

PubMed2007

Strong impact on the polycyclic aromatic hydrocarbon (PAH)-degrading community of a PAH-polluted soil but marginal effect on PAH degradation when priming with bioremediated soil dominated by mycobacteria.

Bioaugmentation of soil polluted with polycyclic aromatic hydrocarbons (PAHs) is often disappointing because of the low survival rate and low activity of the introduced degrader bacteria. We therefore investigated the possibility of priming PAH degradation in soil by adding 2% of bioremediated soil with a high capacity for PAH degradation. The culturable PAH-degrading community of the bioremediated primer soil was dominated by Mycobacterium spp. A microcosm containing pristine soil artificially polluted with PAHs and primed with bioremediated soil showed a fast, 100- to 1,000-fold increase in numbers of culturable phenanthrene-, pyrene-, and fluoranthene degraders and a 160-fold increase in copy numbers of the mycobacterial PAH dioxygenase gene pdo1. A nonpolluted microcosm primed with bioremediated soil showed a high rate of survival of the introduced degrader community during the 112 days of incubation. A nonprimed control microcosm containing pristine soil artificially polluted with PAHs showed only small increases in the numbers of culturable PAH degraders and no pdo1 genes. Initial PAH degradation rates were highest in the primed microcosm, but later, the degradation rates were comparable in primed and nonprimed soil. Thus, the proliferation and persistence of the introduced, soil-adapted degraders had only a marginal effect on PAH degradation. Given the small effect of priming with bioremediated soil and the likely presence of PAH degraders in almost all PAH-contaminated soils, it seems questionable to prime PAH-contaminated soil with bioremediated soil as a means of large-scale soil bioremediation.

Arthrobacter↗

PubMed1996

Straw compost and bioremediated soil as inocula for the bioremediation of chlorophenol-contaminated soil.

We evaluated the use of straw compost and remediated soil as inocula for bioremediation of chlorophenol-contaminated soil. The in situ biotransformation of pentachlorophenol (PCP) and mineralization of radiolabeled [U-(sup14)C]PCP by straw compost and remediated soil were studied under field-simulating conditions before and after 3 months of adaptation with PCP in a percolator. After PCP adaptation, the straw compost mineralized up to 56% of the [(sup14)C]PCP. No partial dechlorination of PCP was found. The native straw compost did not mineralize PCP, but partial dechlorination of PCP occurred (i) at pH 8 under near-thermophilic conditions (45(deg)C) and (ii) at pH 7 under aerobic and mesophilic conditions. No biotransformation reactions occurred at room temperature (25(deg)C) at pH 8. Enrichment in the percolator enhanced the mineralization rate of remediated soil to 56% compared with that of the native remediated soil, which mineralized 24% of [(sup14)C]PCP added. Trace amounts of chloroanisoles as the only biotransformation products were detected in PCP-adapted remediated soil. Both inoculants studied here showed effective mineralization of PCP when they were adapted to PCP in the percolator. No harmful side reactions, such as extensive methylation, were observed.

Journal Article↗

PubMed2005

Surface active properties of bacterial strains isolated from petroleum hydrocarbon-bioremediated soil.

Two bacterial strains identified as Ralstonia picketti (BP 20) and Alcaligenes piechaudii (CZOR L-1B) were isolated from petroleum hydrocarbon-contaminated soil following bioremediation treatment. The surface active properties, e.g. surface tension, emulsification and foamability of their culture filtrates were evaluated. Bacterial cell-surface hydrophobicity (BAH) as measured by analyzing cell affinity towards aliphatic and aromatic compounds was also determinated. The bacteria grew in liquid cultures containing 1% (v/v) of crude oil as carbon and energy source at 30 degrees C under aerobic conditions. The surface tensions were reduced to 61 mN/m and 55 mN/m by Ralstonia picketti and Alcaligenes piechaudii, respectively. The emulsification index (EI24) was almost 100% for all tested compounds except diesel oil. The stability of the emulsions was deteminated at 4 degrees C, 45 degrees C and 65 degrees C. The emulsions were stable at 4 degrees C. Ralstonia picketti was better foam inducer (FV = 50 ml) compared to Alcaligenes piechaudii (FV = 10 ml). The BAH measurements revealed higher adhesion of Alcaligenes piechaudii cells towards different hydrocarbons compared to Ralstonia picketti cells. The strains were found to have a surface hydrophobicity in the following order: aliphatic hydrocarbons, BTEX, and PAHs. The ability to adhere to bulk hydrocarbon is mostly a characteristic of hydrocarbon-degrading bacteria. The strains were found to be better emulsifiers than surface tension reducers. They produce water-soluble extracellular bioemulsifiers. Both bacterial isolates have good properties to use them, mainly in the petroleum industry, e.g. in enhanced oil recovery and in bioremediation processes-primarily due to their emulsification property, i.e. emulsion forming and stabilizing capacity.

Alcaligenes↗

PubMed1998

Genotoxicity of bioremediated soils from the Reilly Tar site, St. Louis Park, Minnesota.

An in vitro approach was used to measure the genotoxicity of creosote-contaminated soil before and after four bioremediation processes. The soil was taken from the Reilly Tar site, a closed Superfund site in Saint Louis Park, Minnesota. The creosote soil was bioremediated in bioslurry, biopile, compost, and land treatment, which were optimized for effective treatment. Mutagenicity profiles of dichloromethane extracts of the five soils were determined in the Spiral technique of the Salmonella assay with seven tester strains. Quantitative mutagenic responses in the plate incorporation technique were then determined in the most sensitive strains, YG1041 and YG1042. Mutagenic potency (revertants per microgram extract) in YG1041 suggested that compost, land treatment, and untreated creosote soil extracts were moderately mutagenic with Arochlor-induced rat liver (S9) but were nonmutagenic without S9. However, the bioslurry extract was strongly mutagenic and the biopile extract was moderately mutagenic either with or without S9. A similar trend was obtained in strain YG1042. The strong mutagenic activity in the bioslurry extract was reduced by 50% in TA98NR, which suggested the presence of mutagenic nitrohydrocarbons. Variation in reproducibility was 15% or less for the bioassay and extraction procedures. Bioavailability of mutagens in the biopile soil was determined with six solvents; water-soluble mutagens accounted for 40% of the total mutagenic activity and they were stable at room temperature. The mutagenic activity in the bioslurry and biopsile samples was due to either the processes themselves or to the added sludge/manure amendments. The in vitro approach was effective in monitoring bioremediated soils for genotoxicity and will be useful in future laboratory and in situ studies.

Animals↗

PubMed2002

Volatile hydrocarbon emissions from a diesel fuel-contaminated soil bioremediation facility.

Concerns have been expressed that emissions of volatile hydrocarbons (HCs) from bioremediation facilities containing soils contaminated with petroleum HCs may negatively impact regional air quality or human health. Little information is available regarding the emission of HCs from bioremediation sites, and few field studies have been performed during which the flux of HCs has been directly measured during bioremediation. To aid in answering questions about the impact of bioremediation facilities on the atmospheric environment, a two-part field study was conducted over summer 1996 at a remote landfarm in northern Ontario where diesel fuel-contaminated soil was undergoing bioremediation. Volatile total hydrocarbon (THC) atmospheric flux measurements were successfully taken over 18 days using a flux gradient micrometeorological technique incorporating a THC detector constructed in-house. Peak THC emissions reached 131 microg C/m2/sec shortly after implementation and tilling of the landfarm soil. The influence of soil temperature and tillage on THC emissions was examined. Off-site inhalation exposure was considered with the aid of an areal source model and results from speciated air samples collected on sorbent tubes and analyzed via gas chromatography/mass spectrometry (GCMS) techniques.

Biodegradation, Environmental↗

PubMed2001

Effect of petrochemical sludge concentrations of changes in mutagenic activity during soil bioremediation process.

The present study was performed to assess the effect of the petrochemical sludge application rate on the mutagenic activity (Ames test) of soil and the persistence of mutagenic activity during laboratory soil bioremediation process. Sludge-soil systems were prepared at four different sludge application rates (1.25, 2.5, 5, and 10% w/w). Unamended soil was used as a control. Immediately following sludge application, in the absence or presence of S9, a linear correlation between sludge application rates and mutagenicity was found but differed significantly (p < 0.05) from the control system only at higher application rates (5 and 10% w/w). The direct mutagenicity of all systems decreases during the bioremediation process, and after a year of treatment only the 10% system induced a mutagenic response that was significantly different from the control system. On the other hand, an initial increase of the indirect mutagenicity was observed at all application rates. The time required for observing this increase was inversely proportional to the initial sludge concentration. After a year of treatment, the indirect mutagenicity of all sludge-amended soils was not significantly different but was significantly different from the unamended soils. The persistence of the direct mutagenic activity of the sludge-amended soils was related to the sludge concentration, whereas the indirect mutagenic persistence was related to the relationship between easily degradable hydrocarbons and polynuclear aromatic hydrocarbons concentration and independent from the initial application rate.

Biodegradation, Environmental↗

PubMed1996

Bioaugmentation as a soil bioremediation approach.

The debate over the efficacy of bioaugmentation rages on, with research continuing to demonstrate that its advantages for soil bioremediation are difficult to predict; however, when it works, the results are often very encouraging. The difficulties arise from, among others, the diversity of the microorganisms used, environmental heterogeneity, and variations in the influence of critical parameters (e.g. humidity, microbial predation and "bioavailability') which, unfortunately, are not even always identified.

Biodegradation, Environmental↗

PubMed2005

Assessment of genotoxic activity of petroleum hydrocarbon-bioremediated soil.

The relationship between toxicity and soil contamination must be understood to develop reliable indicators of environmental restoration for bioremediation. Two bacterial rapid bioassays, SOS chromotest and the umu test with and without metabolic activation (S-9 mixture), were used to evaluate the genotoxicity of petroleum hydrocarbon-contaminated soil following bioremediation treatment. The soil was taken from an engineered biopile at the Czechowice-Dziedzice Polish oil refinery (CZOR). The bioremediation process in the biopile lasted 4 years, and the toxicity measurements were done after this treatment. Carcinogens detected in the soil, polyaromatic hydrocarbons (PAHs), were reduced to low concentrations (2mg/kg dry wt) by the bioremediation process. Genotoxicity was not observed for soils tested with and without metabolic activation by a liver homogenate (S-9 mixture). However, the umu test was more sensitive than the SOS chromotest in the analysis of petroleum hydrocarbon-bioremediated soil. Analytical results of soil used in the bioassays confirmed that the bioremediation process reduced 81% of the petroleum hydrocarbons including PAHs. We conclude that the combined test systems employed in this study are useful tools for the genotoxic examination of remediated petroleum hydrocarbon-contaminated soil.

Biodegradation, Environmental↗

PubMed2005

Effect of petrochemical sludge concentrations on microbial communities during soil bioremediation.

Qualitative and quantitative changes of microbial communities in soil microcosms during bioremediation were determined throughout one year. The soil was contaminated with 0%, 2.5%, 5%, 10% (wt/wt) of petrochemical sludge containing polynuclear aromatic hydrocarbons. We analyzed the hydrocarbon concentration in the microcosms, the number of cultivable bacteria using CFU and most probable number assays, the community structure using denaturing gradient gel electrophoresis, and the metabolic activity of soil using dehydrogenase activity and substrate-induced respiration assays. After one year of treatment, the chemical analysis suggested that the hydrocarbon elimination process was over. The biological analysis, however, showed that the contaminated microcosms suffered under long-term disturbance. The number of heterotrophic bacteria that increased after sludge addition (up to 10(8)-10(9) cells ml(-1)) has not returned to the level of the control soil (2-6 x 10(7) cells ml(-1)). The community structure in the contaminated soils differed considerably from that in the control. The substrate-induced respiration of the contaminated soils was significantly lower (approximately 10-fold) and the dehydrogenase activity was significantly higher (20-40-fold) compared to the control. Changes in the community structure of soils depended on the amount of added sludge. The species, which were predominant in the sludge community, could not be detected in the contaminated soils.

Biodegradation, Environmental↗

PubMed2005

An insight into soil bioremediation through respirometry.

Respirometric tests on a soil contaminated by crude oil were performed. Continuous measurements of oxygen and carbon dioxide concentrations and temperature in the soil atmosphere resulted in a large volume of data. Time series and system identification theories were used to analyze data as a biological signal, allowing us to detect some particularities related to daily cycles of the studied variables as well as its time relationships through autocorrelation and cross-correlation functions. Using system identification techniques, it was possible to build black box models, namely autoregressive moving average models which enable to predict oxygen concentration at the outlet in a good agreement with measured data.

Biodegradation, Environmental↗

PubMedDate not supplied

[Use of micromycetes Trichoderma for soil bioremediation in tree nurseries].

Data were obtained on the improvement of soil microbiocenoses in artificial ecosystems after the introduction of micromycetes Trichoderma. Application of biologically active substances released by some of aboriginal microbial strains can solve bioremediation problems in a given region at a low cost.

Animals↗

PubMed1998

Bioassay-directed fractionation and chemical identification of mutagens in bioremediated soils.

Soil from a Superfund site (Reilly Tar Site, St. Louis Park, Minnesota) contaminated with polycyclic aromatic hydrocarbons (PAHs) from creosote was treated with several bioremediation technologies including bioslurry (BS), biopile (BP), compost (CMP), and land treatment (LT). These treatment technologies are being evaluated in pilot scale laboratory systems by the U.S. Environmental Protection Agency's National Risk Management Research Laboratory in Cincinnati, Ohio. To evaluate the genotoxicity and identify the mutagens in the soil before and after the various treatments, fractionated extracts of five soils were bioassayed for mutagenic activity with a microsuspension modification of the Salmonella histidine reversion assay. Soils were extracted by sonication using dichloromethane (DCM). The five extracts were fractionated in triplicate (two for bioassay and one for chemical analysis) by reverse-phase high-performance liquid chromatography (HPLC) using hexane/DCM/methanol, and the fraction for bioassay were solvent-exchanged into dimethyl sulfoxide by nitrogen evaporation. Forty HPLC fractions for each sample were bioassayed in strain YG1041 with and without exogenous liver metabolic activation. As shown in a companion paper, the mutagenicity of two treatments (BS and BP) was significantly greater than the mutagenicity of the untreated soil. Mutagenic fractions (> 500 revertants) were analyzed by gas chromatography/mass spectrometry (GC/MS). PAH analysis of the soils indicated that all treatments were effective in reducing the total PAH concentration (48-74%). Qualitative GC/MS analysis of the mutagenic fractions from the BS and BP treatments indicated that they contained azaarenes, which are mutagens. The CMP and LT processes were the most effective and least toxic bioremediation procedures based on mutagenic potency and chemical analysis. This research demonstrated that the combination of bioassays and chemical analysis provided a more accurate determination of toxicity in these complex environmental mixtures.

Biological Assay↗

PubMed2000

Irpex lacteus, a white rot fungus applicable to water and soil bioremediation.

Growth parameters, ligninolytic enzyme activities and ability to degrade polycyclic aromatic hydrocarbons by the fungus Irpex lacteus were characterized and compared with those of other white rot fungi capable of rapid decolorization of poly R-478 and Remazol Brilliant Blue R dyes. I. lacteus was able to grow on mineral and complex media and efficiently colonized sterile and non-sterile soil by exploratory mycelium growing from a wheat straw inoculum. In shallow stationary cultures growing on high nitrogen mineral medium containing 45 mM ammonium as nitrogen source, the fungus produced lignin peroxidase (LIP), Mn-dependent peroxidase (MnP) and laccase simultaneously, the respective maximal activities of 70, 970 and 36 U/l being attained around day 18. Growing in nitrogen-limited medium (2.4 mM ammonium), no LIP was formed and levels of MnP and laccase decreased significantly. During growth in sterile soil, the fungus synthesized LIP and laccase but not MnP. I. lacteus efficiently removed three- and four-ringed PAHs from liquid media and artificially spiked soil. The variety of ligninolytic enzymes, robust growth, capability of soil colonization and resistance to inhibitory action of soil bacteria make I. lacteus a suitable fungal organism for use in bioremediation.

Basidiomycota↗

PubMed2006

An evaluation of soil colonisation potential of selected fungi and their production of ligninolytic enzymes for use in soil bioremediation applications.

Initially sixteen fungi were screened for potential ligninolytic activity using decolourisation of a polymeric dye Poly R-478. From this, four fungi were selected, Trametes versicolor, Pleurotus ostreatus, Collybia sp., and an isolate (identified as Rhizoctonia solani) isolated from a grassland soil. Differences in the ligninolytic enzyme profiles of each of the fungi were observed. All of the four fungi tested produced MnP and laccase while the Collybia sp. and R. solani produced LiP in addition. Enzyme activity levels also varied greatly over the 21 days of testing with T. versicolor producing levels of MnP and laccase three to four times greater than the other fungi. The four fungi were then tested for their ability to colonise sand, peat (forest) and basalt and marl mixed till (field) soils through visual measurement and biomass detection in soil microcosms. Trametes versicolor and the Collybia sp. failed to grow in any of the non-sterilised soils whereas the R. solani and P. ostreatus isolates grew satisfactorily. Primers were designed to detect MnP and laccase genes in P. ostreatus and RTPCR was used to detect that these genes are expressed in forest and field soils.

Anthraquinones↗

PubMed1994

Ecotox-evaluation strategy for soil bioremediation exemplified for a PAH-contaminated site.

During a bioremediation of a PAH-contaminated site chemical and biological analyses were carried out. The biological investigations included ecotoxicological analyses in the aqueous extract, (Pseudomonas putida, Photobacterium phosphoreum, daphnids, algae, fish) and analyses in the soil with introduced organisms (plants, earthworms) and natural soil organisms (nematodes, microorganisms). In all test systems a correspondence between decreasing toxicity and degradation of the easily biodegradable PAHs was found. From investigations with aqueous extracts therefore not only conclusions on potential risks for groundwater can be drawn, but these tests also seem to allow risk assessments for soil inhabitants. Furthermore with these tests comprising dilution series the extent of toxicity for soil organisms can be quantified more precisely than with terrestrial investigations. Of all aquatic test systems a constant remaining toxicity was found only in the Microtox text. The test with Daphnia magna indicated the intermediate formation of organism specific toxic metabolites. Therefore useful information may be obtained with biological analyses which complement chemical analyses. For an extensive assessment of a contaminated site a test battery is advisable.

Animals↗

PubMed2002

Immobilized native bacteria as a tool for bioremediation of soils and waters: implementation and modeling.

Based on 3,4-dihydroxyphenylacetate (3,4-DHPA) dioxygenase amino acid sequence and DNA sequence data for homologous genes, two different oligonucleotides were designed. These were assayed to detect 3,4-DHPA related aromatic compound-degrading bacteria in soil samples by using the FISH method. Also, amplification by PCR using a set of ERIC primers was assayed for the detection of Pseudomonas GCH1 strain, which used in the soil bioremediation process. A model was developed to understand and predict the behavior of bacteria and pollutants in a bioremediation system, taking into account fluid dynamics, molecular/cellular scale processes, and biofilm formation.

Alginates↗

PubMed2000

Estimating the availability of polycyclic aromatic hydrocarbons for bioremediation of creosote contaminated soils.

Bioremediation of soil contaminated by organic compounds can remove the contaminants to a large extent, but residual contamination levels may remain which are not or only slowly biodegraded. Residual levels often exceed existing clean-up guidelines and thereby limit the use of bioremediation in site clean-up. A method for estimating the expected residual levels would be a useful tool in the assessment of the feasibility of bioremediation. In this study, three soil types from a creosote-contaminated field site, which had been subjected to 6 months of bioremediation in laboratory column studies, were used to characterize the residual contamination levels and assess their availability for biodegradation. The soils covered a wide range of organic carbon levels and particle size distributions. Results from the biodegradation studies were compared with desorption rate measurements and selective extractability using butanol. Residual levels of polycyclic aromatic hydrocarbons after bioremediation were found to be strongly dependent on soil type. The presence of both soil organic matter and asphaltic compounds in the soil was found to be associated with higher residual levels. Good agreement was found between the biodegradable fraction and the rapidly desorbable fraction in two of the three soils studied. Butanol extraction was found to be a useful method for roughly estimating the biodegradable fraction in the soil samples. The results indicate that both desorption and selective extraction measurements could aid the assessment of the feasibility for bioremediation and identifying acceptable end-points.

Biodegradation, Environmental↗