This research study explored the efficacy of leaf litter compost as a sustainable soil amendment with the objective of promoting soil health and mitigating the accumulation of potentially toxic elements. The investiga...This research study explored the efficacy of leaf litter compost as a sustainable soil amendment with the objective of promoting soil health and mitigating the accumulation of potentially toxic elements. The investigation encompassed the impact of various organic compost amendments, including leaf compost, cow dung manure, kitchen waste compost, municipal organic waste compost, and vermicompost. The study employed Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to evaluate soil nutrient levels and concentrations of Potentially Toxic Elements (PTEs) such as arsenic, chromium, cadmium, mercury, lead, nickel, and lithium. The fertilization and bioremediation potential of these compost amendments are quantified using an indexing method. Results indicated a substantial increase in overall nutrient levels (carbon, nitrogen, phosphorus, potassium, and sulfur) in soils treated with leaf compost and other organic composts. Fertility indices (FI) are notably higher in compost-amended soils (ranging from 2.667 to 3.938) compared to those amended with chemical fertilizers (ranging from 2.250 to 2.813) across all soil samples. Furthermore, the mean concentrations of PTEs were significantly lower in soils treated with leaf compost and other organic compost amendments compared to those treated with chemical fertilizers amendments. The assessment through the indexing method revealed a high clean index (CI) for leaf compost amendment (ranging from 3.407 to 3.58), whereas the chemical fertilizer amendment exhibits a relatively lower CI (ranging from 2.78 to 3.20). Consequently, leaf compost and other organic composts exhibit the potential to enhance sustainable productivity, promoting soil health and environmental safety by improving nutrient levels and remediating potentially toxic elements in the soil.展开更多
The pollution of ecosystems as a result of urbanization, industrialization and poor agricultural practices is becoming increasingly alarming. This has a major impact on health and the economy. This pollution causes il...The pollution of ecosystems as a result of urbanization, industrialization and poor agricultural practices is becoming increasingly alarming. This has a major impact on health and the economy. This pollution causes illness in humans and animals, even at low levels of exposure, leading to endocrine disorders, congenital malformations, cardiovascular disease, nervous system damage and cancer. They are a brake on redevelopment because of the threats they pose, generally causing an anaerobic environment by blocking the diffusion of air into the soil pores, thus affecting the microbial communities living there and preventing the infiltration of water necessary for plant growth. In an ecosystem subjected to various disturbances, changes can be observed in ecosystem structure and function, including loss of aesthetic values, changes in biomass or productivity, and changes in species composition. These include loss of aesthetic values, changes in biomass or productivity, and altered species composition, as a result of habitat loss, disruption of food webs and variations in macro- and micro-climatic environmental conditions. Respect for the environment is becoming a major concern in today’s society. To remedy this, the concept of biological control was used as an alternative, with the selection of microorganisms of bioremediator interest. Twenty (20) isolates, including 10 (50%) from the Pseudomonas genus and 10 (50%) from the Bacillus genus, were isolated from landfills, identified and tested to assess their biofertilization (phosphate solubilization) and depollution (hydrocarbon degradation) potential, and to inhibit the growth of certain microorganisms. The results showed that all Pseudomonas and Bacillus isolates solubilized inorganic phosphate, although this activity was higher in Bacillus. All Bacillus inhibited the growth of all the pathogens included in this study, while Pseudomonas only inhibited the growth of E. coli. With regard to their ability to degrade hydrocarbons, these bacteria all showed exponential growth kinetics in the presence of gasoline. These kinetics evolved as a function of the number of days. The results obtained from this work leave no doubt as to the capacity of microorganisms to be used on a large scale as soil biofertilizers to restore soil integrity and promote sustainable agriculture, but also as biodepollutants to purify ecosystems.展开更多
The comparative effectiveness of remediating water polluted with crude oil, using environment-friendly bacteria (Pseudomonas aeruginosa) and fungi (Aspergillus niger) were investigated. The samples were separately tre...The comparative effectiveness of remediating water polluted with crude oil, using environment-friendly bacteria (Pseudomonas aeruginosa) and fungi (Aspergillus niger) were investigated. The samples were separately treated with Aspergillus niger and Pseudomonas aeruginosa. The bioremediation kinetic efficiency for these systems was studied. At the end of the bioremediation periods, the oil and grease content of the samples decreased from 47.0 mg/L in the untreated sample to 7.0 mg/L after 20 days when inoculated with bacteria while the sample inoculated with fungi decreased to 10.0 mg/L. Post analysis when inoculated with bacteria showed a fall in the value of the biological oxygen demand (BOD) from 73.84 mg/L to 33.28 mg/L after 20 days, while, the fungi inoculated sample showed a reduction from 73.84 mg/L to 38.48 mg/L. The biodegradation process with the bacteria was consistent with the pseudo-first-order model with a rate constant of 0.0891 day<sup>-1</sup>, while the biodegradation process with the fungi was consistent with the first order reaction model with a rate constant of 0.422 day<sup>-1</sup>. The degree of degradation after the 20<sup>th</sup> day of inoculation with Pseudomonas aeruginosa was 85.11%, while with Aspergillus niger was 78.72%. Thus, the results obtained showed that, Pseudomonas aeruginosa performed better than Aspergillus niger. The bioremediation data with fungi fitted the first-order model, while that of the bacteria fitted the pseudo-first-order model. Therefore, the data obtained in this study could be applied in the design of a bioremediation system for potential application to remediation of crude oil polluted water.展开更多
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/...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.展开更多
[ Objective ] The aim was to study the bioremediation mechanism of soil pollution. [ Method ] The effects of applying biological organic fertilizers on the bioremediation of soil pollution in orchard were studid by ex...[ Objective ] The aim was to study the bioremediation mechanism of soil pollution. [ Method ] The effects of applying biological organic fertilizers on the bioremediation of soil pollution in orchard were studid by experiment in orchard field and soil simulative experiment. [ Result] The biological organic fertilizers improved the activities of enzymes like polyphenol oxidase, urease, phosphatase, etc. in root-zone soil, promoted the passivation of heavy metals like Cd^2+ , Pb^2+ , Cr^3+ , As^8+ , etc. in root-zone soil, increased the quantities of useful active bacterium like beneficial fungi, actinomycetes, bacterium, etc. and decreased the quantities of harmful biology (like Fusarium oxysporum, Moniliophthora roreri, Ruselliniu necutrix/Helicobasidium mompa, nematode, etc. [ Conclusion] The study results provide some references for the popularization and application of biological organic fertilizers on fruit trees.展开更多
In order to implement industrial production of selected functional bacteria for bioremediation of shrimp culture environment, the fermentation conditions of the three functional bacteria, which have high ability in de...In order to implement industrial production of selected functional bacteria for bioremediation of shrimp culture environment, the fermentation conditions of the three functional bacteria, which have high ability in degrading organic pollutants at the bottom of shrimp ponds, were studied. The results showed that the favorable fermentation medium (per L) was 25 g of peptone, 5 g of yeast extract, and 0.2 g of ferric phosphate, and the initial pH value of the medium was 8.0. The optimum fermentation time was 20 h. The optimum stirring way was stirring one hour after one hour. Iso-electric point sedimentation collecting method was the most efficient and economic method to collect the bacteria cells after fermentation, with the optimum sediment pH of 3.67, 4.02, and 3.40 for the strains Lt7222, Gy7018 and Lt7511,respectively. It was also indicated that the survival and reproducing ability of the bacterial cells were not affected by the sedimentation process.展开更多
Statistical work and analysis were made based on data of monitored wa- ter quality data in Hedi Reservoir during 2000-2010 and the results show that the content of nutritive salt was higher and water was moderate or l...Statistical work and analysis were made based on data of monitored wa- ter quality data in Hedi Reservoir during 2000-2010 and the results show that the content of nutritive salt was higher and water was moderate or light eutrophication. Based on status quo and practical survey research of the Reservoir, the causes for eutrophication deterioration were analyzed and countermeasures were proposed, providing scientific references for sustainable development of Hedi Reservoir.展开更多
Laboratory simulation studies and composting pilot study wereconducted to evaluate the capacity of three strains of fungi,indigenous fungus Fusarium sp. And Phanerochaete chrysosporium andCoriolus Versicolor, to remed...Laboratory simulation studies and composting pilot study wereconducted to evaluate the capacity of three strains of fungi,indigenous fungus Fusarium sp. And Phanerochaete chrysosporium andCoriolus Versicolor, to remediate petroleum-contaminated soils. Inlaboratory, the fungi were inoculated into a liquid Culture mediumand the petroleum-contaminated soil samples for incubation of 40 and50 days, respectively. In the 200-day pilot study, nutrient contentsand moisture were adjusted and maintained under aerobic Condition incomposting units using concrete container (118.5 cm×65.5 cm×12.5cm) designed specially For this study.展开更多
Along with the rapid development of oil industries internationally,petroleum prospecting and exploitation activities are growing intensively.Especially in China,with the fastest economic growth in the world and shorta...Along with the rapid development of oil industries internationally,petroleum prospecting and exploitation activities are growing intensively.Especially in China,with the fastest economic growth in the world and shortage of petroleum resources,we are leading the practices of petroleum deep exploitation.Obviously,the risk of damage to the natural environment from these activities is high.Oil contamination in soils and groundwater is becoming a big issue along with pesticide pollution,which makes organic pollution prevention and control (OPPC) much more complex.In this paper,based on recent research on oil-contaminated soil at home and abroad,we make comments on the remediation technologies for polluted soil,emphasizing bioremediation techniques and degradation mechanisms in order to push forward research into bound organic pollution prevention and control (OPPC),especially in China.展开更多
A bacterial strain (AD26) capable of utilizing atrazine as a sole nitrogen source for growth was isolated from an industrial wastewater sample by enrichment culture. The 16S rRNA gene sequencing identified AD26 as an ...A bacterial strain (AD26) capable of utilizing atrazine as a sole nitrogen source for growth was isolated from an industrial wastewater sample by enrichment culture. The 16S rRNA gene sequencing identified AD26 as an Arthrobacter sp. PCR assays indicated that AD26 contained atrazine-degrading genes trzN and atzBC. The trzN gene of AD26 only differs from the trzN of Arthrobacter aurescens TC1 by one base (A→T at 907) and one amino acid (Met→Leu at 303). The specific activity of trzN of AD26 in crude cell ext...展开更多
The present study was aimed to assess the ability of Bacillus sp.JDM-2-1 and Staphylococcus capitis to reduce hexavalent chromium into its trivalent form.Bacillus sp.JDM-2-1 could tolerate Cr(Ⅵ)(4800 μg/mL) and ...The present study was aimed to assess the ability of Bacillus sp.JDM-2-1 and Staphylococcus capitis to reduce hexavalent chromium into its trivalent form.Bacillus sp.JDM-2-1 could tolerate Cr(Ⅵ)(4800 μg/mL) and S.capitis could tolerate Cr(Ⅵ)(2800 μg/mL).Both organisms were able to resist Cd^2+(50 μg/mL),Cu^2+(200 μg/mL),Pb^2+(800 μg/mL),Hg^2+(50 μg/mL) and Ni2+(4000 μg/mL).S.capitis resisted Zn^2+ at 700 μg/mL while Bacillus sp.JDM-2-1 only showed resistance up to 50 μg/mL.Bacillus sp.JDM-2-1 and S.capitis showed optimum growth at pH 6 and 7,respectively,while both bacteria showed optimum growth at 37°C.Bacillus sp.JDM-2-1 and S.capitis could reduce 85% and 81% of hexavalent chromium from the medium after 96 h and were also capable of reducing hexavalent chromium 86% and 89%,respectively,from the industrial effuents after 144 h.Cell free extracts of Bacillus sp.JDM-2-1 and S.capitis showed reduction of 83% and 70% at concentration of 10 μg Cr(Ⅵ)/mL,respectively.The presence of an induced protein having molecular weight around 25 kDa in the presence of chromium points out a possible role of this protein in chromium reduction.The bacterial isolates can be exploited for the bioremediation of hexavalent chromium containing wastes,since they seem to have a potential to reduce the toxic hexavalent form to its nontoxic trivalent form.展开更多
Oil spills have become a serious problem in cold environments with the ever-increasing resource exploitation, transportation, storage, and accidental leakage of oil. Several techniques, including physical, chemical, a...Oil spills have become a serious problem in cold environments with the ever-increasing resource exploitation, transportation, storage, and accidental leakage of oil. Several techniques, including physical, chemical, and biological methods, are used to recover spilled oil from the environment. Bioremediation is a promising option for remediation since it is effective and economic in removing oil with less undue environmental damages. However, it is a relatively slow process in cold regions and the degree of success depends on a number of factors, including the properties and fate of oil spilled in cold environments, and the major microbial and environmental limitations of bioremediation. The microbial factors include bioavailability of hydrocarbons, mass transfer through the cell membrane, and metabolic limitations. As for the environmental limitations in the cold regions, the emphasis is on soil temperatures, freeze-thaw processes, oxygen and nutrients availability, toxicity, and electron acceptors. There have been several cases of success in the polar regions, particularly in the Arctic and sub-Arctic regions. However, the challenges and constraints for bioremediation in cold environments remain large.展开更多
This study examines the possibility of using live spirulina to biologically remove aqueous lead of low concentration (below 50 mg/L) from wastewater. The spirulina cells were first immersed for seven days in five wast...This study examines the possibility of using live spirulina to biologically remove aqueous lead of low concentration (below 50 mg/L) from wastewater. The spirulina cells were first immersed for seven days in five wastewater samples containing lead of different concentrations, and the growth rate was determined by light at wavelength of 560 nm. The 72 h-EC50 (72 h medium effective concentration) was estimated to be 11.46 mg/L (lead). Afterwards, the lead adsorption by live spirulina cells was conducted. It was observed that at the initial stage (0–12 min) the adsorption rate was so rapid that 74% of the metal was bio- logically adsorbed. The maximum biosorption capacity of live spirulina was estimated to be 0.62 mg lead per 105 alga cells.展开更多
Effects of bioremediation on microbial communities in soils contaminated with petroleum hydrocarbons are a scientific problem to be solved. Changes in dominate microbial species and the total amount of microorganisms ...Effects of bioremediation on microbial communities in soils contaminated with petroleum hydrocarbons are a scientific problem to be solved. Changes in dominate microbial species and the total amount of microorganisms including bacteria and fungi in rhizospheric soils after bioremediation were thus evaluated using field bioremediation experiments. The results showed that there were changed dominant microorganisms including 11 bacterial strains which are mostly Gram positive bacteria and 6 fungal species which were identified. The total amount of microorganisms including bacteria and fungi increased after bioremediation of microbial agents combined with planting maize. On the contrary, fungi in rhizospheric soils were inhibited by adding microbial agents combined with planting soybean.展开更多
Leakage of oil and its derivatives into the soil can change the engineering behavior of soil as well as cause environmental disasters.Also,recovering the contaminated sites into their natural condition and making cont...Leakage of oil and its derivatives into the soil can change the engineering behavior of soil as well as cause environmental disasters.Also,recovering the contaminated sites into their natural condition and making contaminated materials as both environmentally and geotechnically suitable construction materials need the employment of remediation techniques.Bioremediation,as an efficient,low cost and environmentalfriendly approach,was used in the case of highly plastic clayey soils.To better understand the change in geotechnical properties of highly plastic fine-grained soil due to crude oil contamination and bioremediation,Atterberg limits,compaction,unconfined compression,direct shear,and consolidation tests were conducted on natural,contaminated,and bioremediated soil samples to investigate the effects of contamination and remediation on fine-grained soil properties.Oil contamination reduced maximum dry density(MDD),optimum moisture content(OMC),unconfined compressive strength(UCS),shear strength,swelling pressure,and coefficient of consolidation of soil.In addition,contamination increased the compression and swelling indices and compressibility of soil.Bioremediation reduced soil contamination by about 50%.Moreover,in comparison with contaminated soil,bioremediation reduced the MDD,UCS,swelling index,free swelling and swelling pressure of soil,and also increased OMC,shear strength,cohesion,internal friction angle,failure strain,porosity,compression index,and settlement.Microstructural analyses showed that oil contamination does not alter the soil structure in terms of chemical compounds,elements,and constituent minerals.While it decreased the specific surface area of the soil,and the bioremediation significantly increased the mentioned parameters.Bioremediation resulted in the formation of quasi-fibrous textures and porous and agglomerated structures.As a result,oil contamination affected the mechanical properties of soil negatively,but bioremediation improved these properties.展开更多
Nutrient addition has been proved to be an effective strategy to enhance oil biodegradation in marine shorelines. To determine the optimal range of nutrient concentrations in the bioremediation of oil-polluted beaches...Nutrient addition has been proved to be an effective strategy to enhance oil biodegradation in marine shorelines. To determine the optimal range of nutrient concentrations in the bioremediation of oil-polluted beaches, nitrate was added to the simulated shoreline models in the initial concentration of 1, 5 and 10 mg/L. Whenever the NO3-N concentration declined to 70% of its original value, additional nutrients were supplemented to maintain a certain range. Results showed adding nutrients increased the oil biodegradation level, the counts of petroleum degrading bacteria (PDB) and heterotrophic bacteria (HB), and the promoted efficiency varied depending on the concentration of nitrate. Oil degradation level in 5 mg/L (NO3-N) group reached as much as 84.3% accompanied with the consistently highest counts of PDB; while in l mg/L group oil removal efficiency was only 35.2%, and the numbers of PDB and HB were relatively low compared to the other groups supplemented with nutrients. Although counts of HB in the 10 mg/L group were remarkable, lower counts of PDB resulted in poorer oil removal efficiency (70.5%) compared to 5 mg/L group. Furthermore, it would need more NO3-N (0.371 mg) to degrade 1 mg diesel oil in the 10 mg/L group than in the 5 mg/L group (0.197 mg). In conclusion, Nitrate concentration in 5 mg/L is superior to l and 10 mg/L in the enhancement of diesel oil biodegradation in simulated shorelines.展开更多
An investigation of macrobenthos in the littoral zone was carried out in Tanggu District, Tianjin City in June 2003. This investigation was the only integrated one since 1983 there. Something about macrobenthos invest...An investigation of macrobenthos in the littoral zone was carried out in Tanggu District, Tianjin City in June 2003. This investigation was the only integrated one since 1983 there. Something about macrobenthos investigation was reported in this paper. The results showed that the biomass of macrobenthos of that area was almost at the same level as that of 1983, and the density of macrobenthos increased a little. The biomass of Mactra veneriformis has great effect on the average biomass of that area. The diversity of macrobenthos has changed obviously, and 5 or 6 kinds of macrobenthos have become extinct or decreased greatly. So the ecological structure of macrobenthos has become simpler and unstable. In addition, some ecological methods to remedy the area are discussed in this paper.展开更多
Lead contamination in water is a widespread problem throughout the world and results from industrial use and processing of lead ore. Bio-availability of lead can be hazardous for children and causes mental retardation...Lead contamination in water is a widespread problem throughout the world and results from industrial use and processing of lead ore. Bio-availability of lead can be hazardous for children and causes mental retardation. The use of lead free petrol is one measure to check this pollution, but this heavy metal is also present in industrial effluents and need to be removed before these effluents are discharged to natural land or water and as well as to the environment. Using bioremediation, bacteria could render lead non-bioavailable would provide an alternative option for detoxifying this contaminant in the environment. The property of some species of bacteria and algae, to extract metals from their surroundings, has been utilized to purify industrial effluents. The first step in devising a bioremediation strategy is to identify candidate bacterial strains capable of modifying the contaminant. Biotechnological approaches are recommended for extraction of metal forms can be grown in ponds where effluents (rich in heavy metals) are discharged. The microbes will extract the heavy metals and sequester them inside their cell membranes. The goal of the present study was to examine the capacity of lead resistant bacteria and bioremediation of lead contaminated water.展开更多
With the rapid development of mining,the soil heavy metal contamination is increasingly serious in Shaoguan,directly affecting the production of crops. This paper analyzes the farmland soil heavy metal contamination i...With the rapid development of mining,the soil heavy metal contamination is increasingly serious in Shaoguan,directly affecting the production of crops. This paper analyzes the farmland soil heavy metal contamination in the mining area of Shaoguan and the causes of heavy metal contamination in recent years,brings forward the bioremediation measures to control soil heavy metal contamination,and points out the development direction of bioremediation in farmland soil heavy metal contamination in the mining area.展开更多
With increasing demands of fossil fuel energy, extensive exploration of natural sources has caused a number of large scale accidental spills of crude oil and resulted in some significantly environmental disasters. The...With increasing demands of fossil fuel energy, extensive exploration of natural sources has caused a number of large scale accidental spills of crude oil and resulted in some significantly environmental disasters. The consequence of oil pollution to environment and human health has brought a serious challenge to environmental scientists. Physical and chemical approaches to cleanup oil spills are too expensive and create adverse effects. Bioremediation has shown a great potential and competitive privilege because of environment friendly and cost effective. A number of efficient microbial strains have been identified and isolated, which can effectively degrade various components of petroleum oil. However, the biodegradation efficiency is usually limited by abiotic factors, such as temperature and pH, which are hardly to be controlled in the in situ condition but adequate oxygen supply and nutrient balancing are of importance to impact microbial functions. Therefore, this review especially addresses potential approaches to improving bioremediation of crude oil by supplying solid oxygen and adjusting C: N: P ratio to optimize microbial activities in order to improve the effectiveness and efficacy of bioremediation of crude oil pollutants. In addition, it also elucidates advantages of bioremediation, isolation of selective microbial strains, and evaluation of the biodegradation rates.展开更多
文摘This research study explored the efficacy of leaf litter compost as a sustainable soil amendment with the objective of promoting soil health and mitigating the accumulation of potentially toxic elements. The investigation encompassed the impact of various organic compost amendments, including leaf compost, cow dung manure, kitchen waste compost, municipal organic waste compost, and vermicompost. The study employed Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to evaluate soil nutrient levels and concentrations of Potentially Toxic Elements (PTEs) such as arsenic, chromium, cadmium, mercury, lead, nickel, and lithium. The fertilization and bioremediation potential of these compost amendments are quantified using an indexing method. Results indicated a substantial increase in overall nutrient levels (carbon, nitrogen, phosphorus, potassium, and sulfur) in soils treated with leaf compost and other organic composts. Fertility indices (FI) are notably higher in compost-amended soils (ranging from 2.667 to 3.938) compared to those amended with chemical fertilizers (ranging from 2.250 to 2.813) across all soil samples. Furthermore, the mean concentrations of PTEs were significantly lower in soils treated with leaf compost and other organic compost amendments compared to those treated with chemical fertilizers amendments. The assessment through the indexing method revealed a high clean index (CI) for leaf compost amendment (ranging from 3.407 to 3.58), whereas the chemical fertilizer amendment exhibits a relatively lower CI (ranging from 2.78 to 3.20). Consequently, leaf compost and other organic composts exhibit the potential to enhance sustainable productivity, promoting soil health and environmental safety by improving nutrient levels and remediating potentially toxic elements in the soil.
文摘The pollution of ecosystems as a result of urbanization, industrialization and poor agricultural practices is becoming increasingly alarming. This has a major impact on health and the economy. This pollution causes illness in humans and animals, even at low levels of exposure, leading to endocrine disorders, congenital malformations, cardiovascular disease, nervous system damage and cancer. They are a brake on redevelopment because of the threats they pose, generally causing an anaerobic environment by blocking the diffusion of air into the soil pores, thus affecting the microbial communities living there and preventing the infiltration of water necessary for plant growth. In an ecosystem subjected to various disturbances, changes can be observed in ecosystem structure and function, including loss of aesthetic values, changes in biomass or productivity, and changes in species composition. These include loss of aesthetic values, changes in biomass or productivity, and altered species composition, as a result of habitat loss, disruption of food webs and variations in macro- and micro-climatic environmental conditions. Respect for the environment is becoming a major concern in today’s society. To remedy this, the concept of biological control was used as an alternative, with the selection of microorganisms of bioremediator interest. Twenty (20) isolates, including 10 (50%) from the Pseudomonas genus and 10 (50%) from the Bacillus genus, were isolated from landfills, identified and tested to assess their biofertilization (phosphate solubilization) and depollution (hydrocarbon degradation) potential, and to inhibit the growth of certain microorganisms. The results showed that all Pseudomonas and Bacillus isolates solubilized inorganic phosphate, although this activity was higher in Bacillus. All Bacillus inhibited the growth of all the pathogens included in this study, while Pseudomonas only inhibited the growth of E. coli. With regard to their ability to degrade hydrocarbons, these bacteria all showed exponential growth kinetics in the presence of gasoline. These kinetics evolved as a function of the number of days. The results obtained from this work leave no doubt as to the capacity of microorganisms to be used on a large scale as soil biofertilizers to restore soil integrity and promote sustainable agriculture, but also as biodepollutants to purify ecosystems.
文摘The comparative effectiveness of remediating water polluted with crude oil, using environment-friendly bacteria (Pseudomonas aeruginosa) and fungi (Aspergillus niger) were investigated. The samples were separately treated with Aspergillus niger and Pseudomonas aeruginosa. The bioremediation kinetic efficiency for these systems was studied. At the end of the bioremediation periods, the oil and grease content of the samples decreased from 47.0 mg/L in the untreated sample to 7.0 mg/L after 20 days when inoculated with bacteria while the sample inoculated with fungi decreased to 10.0 mg/L. Post analysis when inoculated with bacteria showed a fall in the value of the biological oxygen demand (BOD) from 73.84 mg/L to 33.28 mg/L after 20 days, while, the fungi inoculated sample showed a reduction from 73.84 mg/L to 38.48 mg/L. The biodegradation process with the bacteria was consistent with the pseudo-first-order model with a rate constant of 0.0891 day<sup>-1</sup>, while the biodegradation process with the fungi was consistent with the first order reaction model with a rate constant of 0.422 day<sup>-1</sup>. The degree of degradation after the 20<sup>th</sup> day of inoculation with Pseudomonas aeruginosa was 85.11%, while with Aspergillus niger was 78.72%. Thus, the results obtained showed that, Pseudomonas aeruginosa performed better than Aspergillus niger. The bioremediation data with fungi fitted the first-order model, while that of the bacteria fitted the pseudo-first-order model. Therefore, the data obtained in this study could be applied in the design of a bioremediation system for potential application to remediation of crude oil polluted water.
文摘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.
基金Supported by Natural Science Foundation of Liaoning Province(20082131)~~
文摘[ Objective ] The aim was to study the bioremediation mechanism of soil pollution. [ Method ] The effects of applying biological organic fertilizers on the bioremediation of soil pollution in orchard were studid by experiment in orchard field and soil simulative experiment. [ Result] The biological organic fertilizers improved the activities of enzymes like polyphenol oxidase, urease, phosphatase, etc. in root-zone soil, promoted the passivation of heavy metals like Cd^2+ , Pb^2+ , Cr^3+ , As^8+ , etc. in root-zone soil, increased the quantities of useful active bacterium like beneficial fungi, actinomycetes, bacterium, etc. and decreased the quantities of harmful biology (like Fusarium oxysporum, Moniliophthora roreri, Ruselliniu necutrix/Helicobasidium mompa, nematode, etc. [ Conclusion] The study results provide some references for the popularization and application of biological organic fertilizers on fruit trees.
文摘In order to implement industrial production of selected functional bacteria for bioremediation of shrimp culture environment, the fermentation conditions of the three functional bacteria, which have high ability in degrading organic pollutants at the bottom of shrimp ponds, were studied. The results showed that the favorable fermentation medium (per L) was 25 g of peptone, 5 g of yeast extract, and 0.2 g of ferric phosphate, and the initial pH value of the medium was 8.0. The optimum fermentation time was 20 h. The optimum stirring way was stirring one hour after one hour. Iso-electric point sedimentation collecting method was the most efficient and economic method to collect the bacteria cells after fermentation, with the optimum sediment pH of 3.67, 4.02, and 3.40 for the strains Lt7222, Gy7018 and Lt7511,respectively. It was also indicated that the survival and reproducing ability of the bacterial cells were not affected by the sedimentation process.
基金Supported by Guangdong Natural Science Foundation(8152500002000005)Guangdong Science and Technology Project(2011B030800017)Zhanjiang Normal University Talents Introduction and Undergraduates Innovation Program~~
文摘Statistical work and analysis were made based on data of monitored wa- ter quality data in Hedi Reservoir during 2000-2010 and the results show that the content of nutritive salt was higher and water was moderate or light eutrophication. Based on status quo and practical survey research of the Reservoir, the causes for eutrophication deterioration were analyzed and countermeasures were proposed, providing scientific references for sustainable development of Hedi Reservoir.
基金National Natural Science Foundation of China(No.49831070) the ChineseAcademy of Sciences(No.KZ951-B1-207-01-03).
文摘Laboratory simulation studies and composting pilot study wereconducted to evaluate the capacity of three strains of fungi,indigenous fungus Fusarium sp. And Phanerochaete chrysosporium andCoriolus Versicolor, to remediate petroleum-contaminated soils. Inlaboratory, the fungi were inoculated into a liquid Culture mediumand the petroleum-contaminated soil samples for incubation of 40 and50 days, respectively. In the 200-day pilot study, nutrient contentsand moisture were adjusted and maintained under aerobic Condition incomposting units using concrete container (118.5 cm×65.5 cm×12.5cm) designed specially For this study.
基金supports from the New Century Excellent Talents in University of Ministry of Education (NCET-09-0765)the China Scholarship of Council (2009644509)the Natural Scientific Funds of China (40973064)
文摘Along with the rapid development of oil industries internationally,petroleum prospecting and exploitation activities are growing intensively.Especially in China,with the fastest economic growth in the world and shortage of petroleum resources,we are leading the practices of petroleum deep exploitation.Obviously,the risk of damage to the natural environment from these activities is high.Oil contamination in soils and groundwater is becoming a big issue along with pesticide pollution,which makes organic pollution prevention and control (OPPC) much more complex.In this paper,based on recent research on oil-contaminated soil at home and abroad,we make comments on the remediation technologies for polluted soil,emphasizing bioremediation techniques and degradation mechanisms in order to push forward research into bound organic pollution prevention and control (OPPC),especially in China.
文摘A bacterial strain (AD26) capable of utilizing atrazine as a sole nitrogen source for growth was isolated from an industrial wastewater sample by enrichment culture. The 16S rRNA gene sequencing identified AD26 as an Arthrobacter sp. PCR assays indicated that AD26 contained atrazine-degrading genes trzN and atzBC. The trzN gene of AD26 only differs from the trzN of Arthrobacter aurescens TC1 by one base (A→T at 907) and one amino acid (Met→Leu at 303). The specific activity of trzN of AD26 in crude cell ext...
文摘The present study was aimed to assess the ability of Bacillus sp.JDM-2-1 and Staphylococcus capitis to reduce hexavalent chromium into its trivalent form.Bacillus sp.JDM-2-1 could tolerate Cr(Ⅵ)(4800 μg/mL) and S.capitis could tolerate Cr(Ⅵ)(2800 μg/mL).Both organisms were able to resist Cd^2+(50 μg/mL),Cu^2+(200 μg/mL),Pb^2+(800 μg/mL),Hg^2+(50 μg/mL) and Ni2+(4000 μg/mL).S.capitis resisted Zn^2+ at 700 μg/mL while Bacillus sp.JDM-2-1 only showed resistance up to 50 μg/mL.Bacillus sp.JDM-2-1 and S.capitis showed optimum growth at pH 6 and 7,respectively,while both bacteria showed optimum growth at 37°C.Bacillus sp.JDM-2-1 and S.capitis could reduce 85% and 81% of hexavalent chromium from the medium after 96 h and were also capable of reducing hexavalent chromium 86% and 89%,respectively,from the industrial effuents after 144 h.Cell free extracts of Bacillus sp.JDM-2-1 and S.capitis showed reduction of 83% and 70% at concentration of 10 μg Cr(Ⅵ)/mL,respectively.The presence of an induced protein having molecular weight around 25 kDa in the presence of chromium points out a possible role of this protein in chromium reduction.The bacterial isolates can be exploited for the bioremediation of hexavalent chromium containing wastes,since they seem to have a potential to reduce the toxic hexavalent form to its nontoxic trivalent form.
基金Project supported by the 100 Talents Program of the Chinese Academy of Sciences (No.2004407).
文摘Oil spills have become a serious problem in cold environments with the ever-increasing resource exploitation, transportation, storage, and accidental leakage of oil. Several techniques, including physical, chemical, and biological methods, are used to recover spilled oil from the environment. Bioremediation is a promising option for remediation since it is effective and economic in removing oil with less undue environmental damages. However, it is a relatively slow process in cold regions and the degree of success depends on a number of factors, including the properties and fate of oil spilled in cold environments, and the major microbial and environmental limitations of bioremediation. The microbial factors include bioavailability of hydrocarbons, mass transfer through the cell membrane, and metabolic limitations. As for the environmental limitations in the cold regions, the emphasis is on soil temperatures, freeze-thaw processes, oxygen and nutrients availability, toxicity, and electron acceptors. There have been several cases of success in the polar regions, particularly in the Arctic and sub-Arctic regions. However, the challenges and constraints for bioremediation in cold environments remain large.
文摘This study examines the possibility of using live spirulina to biologically remove aqueous lead of low concentration (below 50 mg/L) from wastewater. The spirulina cells were first immersed for seven days in five wastewater samples containing lead of different concentrations, and the growth rate was determined by light at wavelength of 560 nm. The 72 h-EC50 (72 h medium effective concentration) was estimated to be 11.46 mg/L (lead). Afterwards, the lead adsorption by live spirulina cells was conducted. It was observed that at the initial stage (0–12 min) the adsorption rate was so rapid that 74% of the metal was bio- logically adsorbed. The maximum biosorption capacity of live spirulina was estimated to be 0.62 mg lead per 105 alga cells.
文摘Effects of bioremediation on microbial communities in soils contaminated with petroleum hydrocarbons are a scientific problem to be solved. Changes in dominate microbial species and the total amount of microorganisms including bacteria and fungi in rhizospheric soils after bioremediation were thus evaluated using field bioremediation experiments. The results showed that there were changed dominant microorganisms including 11 bacterial strains which are mostly Gram positive bacteria and 6 fungal species which were identified. The total amount of microorganisms including bacteria and fungi increased after bioremediation of microbial agents combined with planting maize. On the contrary, fungi in rhizospheric soils were inhibited by adding microbial agents combined with planting soybean.
文摘Leakage of oil and its derivatives into the soil can change the engineering behavior of soil as well as cause environmental disasters.Also,recovering the contaminated sites into their natural condition and making contaminated materials as both environmentally and geotechnically suitable construction materials need the employment of remediation techniques.Bioremediation,as an efficient,low cost and environmentalfriendly approach,was used in the case of highly plastic clayey soils.To better understand the change in geotechnical properties of highly plastic fine-grained soil due to crude oil contamination and bioremediation,Atterberg limits,compaction,unconfined compression,direct shear,and consolidation tests were conducted on natural,contaminated,and bioremediated soil samples to investigate the effects of contamination and remediation on fine-grained soil properties.Oil contamination reduced maximum dry density(MDD),optimum moisture content(OMC),unconfined compressive strength(UCS),shear strength,swelling pressure,and coefficient of consolidation of soil.In addition,contamination increased the compression and swelling indices and compressibility of soil.Bioremediation reduced soil contamination by about 50%.Moreover,in comparison with contaminated soil,bioremediation reduced the MDD,UCS,swelling index,free swelling and swelling pressure of soil,and also increased OMC,shear strength,cohesion,internal friction angle,failure strain,porosity,compression index,and settlement.Microstructural analyses showed that oil contamination does not alter the soil structure in terms of chemical compounds,elements,and constituent minerals.While it decreased the specific surface area of the soil,and the bioremediation significantly increased the mentioned parameters.Bioremediation resulted in the formation of quasi-fibrous textures and porous and agglomerated structures.As a result,oil contamination affected the mechanical properties of soil negatively,but bioremediation improved these properties.
基金Project supported by the National Natural Science Foundation of China(No.30670399)the Foundation of Ministry of Construction of China(No.06-K-20).
文摘Nutrient addition has been proved to be an effective strategy to enhance oil biodegradation in marine shorelines. To determine the optimal range of nutrient concentrations in the bioremediation of oil-polluted beaches, nitrate was added to the simulated shoreline models in the initial concentration of 1, 5 and 10 mg/L. Whenever the NO3-N concentration declined to 70% of its original value, additional nutrients were supplemented to maintain a certain range. Results showed adding nutrients increased the oil biodegradation level, the counts of petroleum degrading bacteria (PDB) and heterotrophic bacteria (HB), and the promoted efficiency varied depending on the concentration of nitrate. Oil degradation level in 5 mg/L (NO3-N) group reached as much as 84.3% accompanied with the consistently highest counts of PDB; while in l mg/L group oil removal efficiency was only 35.2%, and the numbers of PDB and HB were relatively low compared to the other groups supplemented with nutrients. Although counts of HB in the 10 mg/L group were remarkable, lower counts of PDB resulted in poorer oil removal efficiency (70.5%) compared to 5 mg/L group. Furthermore, it would need more NO3-N (0.371 mg) to degrade 1 mg diesel oil in the 10 mg/L group than in the 5 mg/L group (0.197 mg). In conclusion, Nitrate concentration in 5 mg/L is superior to l and 10 mg/L in the enhancement of diesel oil biodegradation in simulated shorelines.
基金The paper is supported by the National 863 Program under the contract No. 2002AA648010.
文摘An investigation of macrobenthos in the littoral zone was carried out in Tanggu District, Tianjin City in June 2003. This investigation was the only integrated one since 1983 there. Something about macrobenthos investigation was reported in this paper. The results showed that the biomass of macrobenthos of that area was almost at the same level as that of 1983, and the density of macrobenthos increased a little. The biomass of Mactra veneriformis has great effect on the average biomass of that area. The diversity of macrobenthos has changed obviously, and 5 or 6 kinds of macrobenthos have become extinct or decreased greatly. So the ecological structure of macrobenthos has become simpler and unstable. In addition, some ecological methods to remedy the area are discussed in this paper.
文摘Lead contamination in water is a widespread problem throughout the world and results from industrial use and processing of lead ore. Bio-availability of lead can be hazardous for children and causes mental retardation. The use of lead free petrol is one measure to check this pollution, but this heavy metal is also present in industrial effluents and need to be removed before these effluents are discharged to natural land or water and as well as to the environment. Using bioremediation, bacteria could render lead non-bioavailable would provide an alternative option for detoxifying this contaminant in the environment. The property of some species of bacteria and algae, to extract metals from their surroundings, has been utilized to purify industrial effluents. The first step in devising a bioremediation strategy is to identify candidate bacterial strains capable of modifying the contaminant. Biotechnological approaches are recommended for extraction of metal forms can be grown in ponds where effluents (rich in heavy metals) are discharged. The microbes will extract the heavy metals and sequester them inside their cell membranes. The goal of the present study was to examine the capacity of lead resistant bacteria and bioremediation of lead contaminated water.
基金Supported by National Natural Science Foundation of China(U1033004-06)Guangxi Key Agricultural Science Planning Project(201528)
文摘With the rapid development of mining,the soil heavy metal contamination is increasingly serious in Shaoguan,directly affecting the production of crops. This paper analyzes the farmland soil heavy metal contamination in the mining area of Shaoguan and the causes of heavy metal contamination in recent years,brings forward the bioremediation measures to control soil heavy metal contamination,and points out the development direction of bioremediation in farmland soil heavy metal contamination in the mining area.
文摘With increasing demands of fossil fuel energy, extensive exploration of natural sources has caused a number of large scale accidental spills of crude oil and resulted in some significantly environmental disasters. The consequence of oil pollution to environment and human health has brought a serious challenge to environmental scientists. Physical and chemical approaches to cleanup oil spills are too expensive and create adverse effects. Bioremediation has shown a great potential and competitive privilege because of environment friendly and cost effective. A number of efficient microbial strains have been identified and isolated, which can effectively degrade various components of petroleum oil. However, the biodegradation efficiency is usually limited by abiotic factors, such as temperature and pH, which are hardly to be controlled in the in situ condition but adequate oxygen supply and nutrient balancing are of importance to impact microbial functions. Therefore, this review especially addresses potential approaches to improving bioremediation of crude oil by supplying solid oxygen and adjusting C: N: P ratio to optimize microbial activities in order to improve the effectiveness and efficacy of bioremediation of crude oil pollutants. In addition, it also elucidates advantages of bioremediation, isolation of selective microbial strains, and evaluation of the biodegradation rates.