Polluted Soil Samples Research Articles

Mineral and Heavy Metal Composition of Crude Oil Polluted Soil Amended with Non-Ionic Surfactant (Triton X-100) and White Rot Fungus (Pleurotus ostratus)

The ability of the macro-fungus, Pleurotus ostreatus and non-ionic surfactant (Triton X-100) to degrade crude oil in crude oil polluted soil was investigated with a view to ascertain their efficacy in reducing the toxicity of polluted ecosystem. Crude oil polluted soil samples (2000 g) contained in polypropylene bags (20 cm diameter x 20 cm height) were inoculated with P. ostreatus mycelium and triton x-100 and incubated at 28 to 30°C for 60 days. Crude oil polluted soil samples were analyzed before inoculation and incubation and they served as the control. In all the heavy metals quantified (Pb, Cu, Mn, Cd and Ni), there is a significant difference at P ≤ 0.05 when all the amended cells (B to D) are compared with the control cell (A). For Pb, the concentration of all the cells amended significantly reduced with cells C (PSS+Triton x-100) having the lowest concentration of 1.52 ± 0.02 when compared with the control cell (11.31 ± 0.15). For Cu, Cd and Ni, all the amended cells were seen to be reduced in their concentrations when compared with the concentration of the control sample. For Mn, the concentrations of the amended cells were seen to be high when compared with the concentration of the control sample. For all the mineral elements analyzed (Ca, Mg, Na and K), there is a significant difference at P ≤ 0.05 when all the amended cells (B to D) are compared with the control cell (A). For Ca, there was a significant difference (P ≤ 0.05) when cell A is compared with other cells. Highest reduction in Ca level was seen in cell D (PSS+Pleurotus ostreatus+Triton X-100) with the value of 88.28 ± 2.72. For Mg, all the amended cells were seen to have a significant increase in their values when compared with the control sample (271.15 ± 0.45). For Na and K, only cell B had the highest value of 90.18 ± 0.73 for Na and 371.54 ± 2.26 for K. Cell C was observed to be slightly reduced for Na while cell C and D were also seen to be reduced for K. These results showed that white rot fungus (P. ostreatus) and triton x-100 were able to degrade the polluting oil and as such may be suitable for remediating crude oil polluted soil.

ASSESSMENT ON ANTIMICROBIAL PROPERTIES OF SURFACTIN FROM BACILLUS SUBTILIS ON PROTOPLASTS AND SPHEROPLASTS OF PATHOGENIC BACTERIA

Objective: The aim of this paper is to assessment on antimicrobial properties of surfactin from Bacillus subtilis on protoplasts and spheroplasts of pathogenic bacteria.Methods: Bacillus sp were isolated from the polluted soil samples and these isolates were screened for biosurfactin activity using haemolytic activity. The biosurfactant was also studied for their antibiotic activity and the minimum inhibitory concentration was determined by testing the effect of surfactin on the pathogenic microorganisms. The lytic activity of surfactant was also tested on the protoplasts and spheroplasts of the pathogens.Results: The formation of a clear zone around the colonies and the lysis of erythrocytes shows the antimicrobial and lytic activity of biosurfactants.Conclusion: The results of the current study reveal that surfactin from B. subtilis possesses significant antimicrobial and lytic activity.

STUDIES ON BIOACTIVE POTENTIAL OF STREPTOMYCES SPP. (KX710212). ISOLATED FROM ENVIRONMENTAL POLLUTED SAMPLE, RANIPET, VELLORE, INDIA

ABSTRACTObjective: Natural products from bacterial origin played and still play a valuable role in drug discovery and provide diverse health-promotingcompounds that help to cure or alleviate serious diseases.Methods: A total of 4 actinobacterial strains were isolated from 2 different environmental polluted soil samples collected from Ranipet, Vellore, TamilNadu, India. Of 15 isolates screened for antibacterial property, 4 isolates (PS1, PS2, and PS3) were found potent and characterized phenotypically andgenotypically.Results: The 16S rDNA gene sequences of potent strain showed 97% similarity with Streptomyces spp. and termed as Streptomyces sp. The bioactivitywas revealed by antibacterial and antioxidant activity.Conclusion: Hence, these findings provide scientific evidence to validate the pharmacological use and have the potential contribution in the discoveryof new lead that play a key role in the field of therapeutics.Keywords: Actinomycetes, Bioactive compounds, Antibacterial property.

Targeting of detoxification potential of microorganisms and plants for cleaning environment polluted by organochlorine pesticides

The goal of presented work is the development phytoremediation method targeted to cleaning environment polluted with organochlorine pesticides, based on joint application of specially selected plants and microorganisms. Initial degradation of pesticides carry out by microorganisms; the forming dehalogenated products easily uptake by the plants and undergo oxidative degradation via plant detoxification enzymes. This approach can complete degradation of toxicants and their mineralization into nontoxic compounds. In the presented work the results of using selected strains from genera Pseudomonas and plants phytoremediators in the model experiments are given. It has been shown that the using developed technological approach effectively decreased degree of pollution in artificially polluted soil samples.

Toxic airborne S, PAH, and trace element legacy of the superhigh-organic-sulphur Raša coal combustion: Cytotoxicity and genotoxicity assessment of soil and ash

This paper presents the levels of sulphur, polycyclic aromatic hydrocarbons (PAHs), and potentially toxic trace elements in soils surrounding the Plomin coal-fired power plant (Croatia). It used domestic superhigh-organic-sulphur Raša coal from 1970 until 2000. Raša coal was characterised by exceptionally high values of S, up to 14%, making the downwind southwest (SW) area surrounding the power plant a significant hotspot. The analytical results show that the SW soil locations are severely polluted with S (up to 4%), and PAHs (up to 13,535ng/g), while moderately with Se (up to 6.8mg/kg), and Cd (up to 4.7mg/kg). The composition and distribution pattern of PAHs in the polluted soils indicate that their main source could be airborne unburnt coal particles. The atmospheric dispersion processes of SO2 and ash particles have influenced the composition and distribution patterns of sulphur and potentially toxic trace elements in studied soils, respectively. A possible adverse impact of analysed soil on the local karstic environment was evaluated by cytotoxic and genotoxic methods. The cytotoxicity effects of soil and ash water extracts on the channel catfish ovary (CCO) cell line were found to be statistically significant in the case of the most polluted soil and ash samples. However, the primary DNA-damaging potential of the most polluted soil samples on the CCO cells was found to be within acceptable boundaries.

Response and resilience of soil microbial communities inhabiting in edible oil stress/contamination from industrial estates.

BackgroundGauging the microbial community structures and functions become imperative to understand the ecological processes. To understand the impact of long-term oil contamination on microbial community structure soil samples were taken from oil fields located in different industrial regions across Kadi, near Ahmedabad, India. Soil collected was hence used for metagenomic DNA extraction to study the capabilities of intrinsic microbial community in tolerating the oil perturbation.ResultsTaxonomic profiling was carried out by two different complementary approaches i.e. 16S rDNA and lowest common ancestor. The community profiling revealed the enrichment of phylum “Proteobacteria” and genus “Chromobacterium,” respectively for polluted soil sample. Our results indicated that soil microbial diversity (Shannon diversity index) decreased significantly with contamination. Further, assignment of obtained metagenome reads to Clusters of Orthologous Groups (COG) of protein and Kyoto Encyclopedia of Genes and Genomes (KEGG) hits revealed metabolic potential of indigenous microbial community. Enzymes were mapped on fatty acid biosynthesis pathway to elucidate their roles in possible catalytic reactions.ConclusionTo the best of our knowledge this is first study for influence of edible oil on soil microbial communities via shotgun sequencing. The results indicated that long-term oil contamination significantly affects soil microbial community structure by acting as an environmental filter to decrease the regional differences distinguishing soil microbial communities.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-016-0669-8) contains supplementary material, which is available to authorized users.

Pathogenic Yet Environmentally Friendly? Black Fungal Candidates for Bioremediation of Pollutants

ABSTRACTA collection of 163 strains of black yeast-like fungi from the CBS Fungal Biodiversity Center (Utrecht, The Netherlands), has been screened for the ability to grow on hexadecane, toluene and polychlorinated biphenyl 126 (PCB126) as the sole carbon and energy source. These compounds were chosen as representatives of relevant environmental pollutants. A microtiter plate-based culture assay was set up in order to screen the fungal strains for growth on the selected xenobiotics versus glucose, as a positive control. Growth was observed in 25 strains on at least two of the tested substrates. Confirmation of substrate assimilation was performed by cultivation on closed vials and analysis of the headspace composition with regard to the added volatile substrates and the generated carbon dioxide. Exophiala mesophila (CBS 120910) and Cladophialophora immunda (CBS 110551), both of the order Chaetothyriales and isolated from a patient with chronic sinusitis and a polluted soil sample, respectively, showed the ability to grow on toluene as the sole carbon and energy source. Toluene assimilation has previously been described for C. immunda but this is the first account for E. mesophila. Also, this is the first time that the capacity to grow on alkylbenzenes has been demonstrated for a clinical isolate. Assimilation of toluene could not be demonstrated for the human opportunistic pathogen Pseudoallescheria boydii (CBS 115.59, Microascales), but the results from microtiter plate assays suggest that strains of this species are promising candidates for further studies. The outstanding abilities of black yeast-like fungi to thrive in extreme environments makes them ideal agents for the bioremediation of polluted soils, and for the treatment of contaminated gas streams in biofilters. However, interrelations between hydrocarbonoclastic and potentially pathogenic strains need to be elucidated in order to avoid the possibility of biohazards occurring.

Studies on the Seed Germination Changes after Thermal Decontamination of Crude Oil Polluted Soils

Abstract Given that the world population will reach nearly 10 billion by 2050, removing all the causes that result in reduced yields of cereals and technical plants is vital. It is known that soil affects plants through its physical (texture, structure, density), chemical (nutrients content, pH) and biological characteristics (microbiological activity, soil fertility). Soils are the key environmental tank to pollutants, storage and persistence of pollutants in soil being dependent on a number of factors: the exchange of air, the burying of pollutants and their biodegradability. This paper aims to emphasize the germination of plants after a polluted soil sample was decontaminated by a thermal method. The soil sample was polluted with 5% oil. The soil sample was characterized by capillarity, being established the maximum height of the moistened layer of 7.6 cm and 14.1 cm for oil, but also permeability of 218.5 cm3/h for water and 70.83 cm3/h for oil. Knowing the average permeability, it can be determined the corresponding retention capacity: 873.14 kg/m3 for water and 776 kg/m3 for oil. Restoration of the germination potential for the analyzed soil also determined the presence of nutrients required before and after remediation. The analyzed nutrients were nitrogen, phosphorus and potassium. The soil sample had no nitrogen, but phosphorus and potassium were in medium concentration. The soil sample that was polluted with oil and decontaminated by a thermal method, has nitrogen, the potassium content does not change, but the phosphorus content increases.

Characterization of Indigenous Bacterial Communities in Crude-Oil Impacted Sites at Obagi Town, Onelga, Rivers State, Nigeria

Hydrocarbon utilizers are expected to be indigenous in crude-oil polluted environments. The isolation and characterization of hydrocarbon utilizers is often a key strategy in bioremediation of hydrocarbon-polluted environments. In this study, crude-oil polluted soil samples from Obagi town, Onelga, Rivers state were enumerated and characterized for putative hydrocarbon utilizing bacterial populations. Biochemical characterization identified five bacterial species representative of five genera: Bacillus, Pseudomonas, Acinetobacter, Micrococcus and Staphylococcus. Amongst the genera of bacteria isolated, Bacillus had the highest frequency of occurrence (40%). The mean count of total heterotrophic bacteria was 1.7 X 107 cfu/g, while hydrocarbon utilizing bacteria (HUB) count mean density was 1.0 X 107 cfu/g for the three soil samples. Statistical analyses revealed no significant difference at p>0.05 between Total Heterotrophic Bacterial (THB) and Hydrocarbon Utilizing Bacterial (HUB) counts, suggesting that most of the bacteria present in the sampled sites were hydrocarbon utilizers. Findings from this study suggest the presence of indigenous putative hydrocarbon utilizing bacteria in the crude-oil polluted soil of Obagi town. Hence, a promising potential exists for future bioremediation studies on the site.

Are physico-chemical soil characteristics key factors to select the polycyclic aromatic hydrocarbons extraction procedure?

ABSTRACTThe aim of this work was to assess the impact of soil characteristics and constituents in the total extraction of hydrophobic organic pollutants, such as polycyclic aromatic hydrocarbons (PAH), in real polluted soil samples from different sources. Soil samples were obtained from a wood creosote treatment plant, in the vicinity of a metallurgy industry and coal thermal power stations. Soils showed a wide diversity of textures, organic matter (OM) and CaCO3 content, pH and electrical conductivity to assure representativeness of multiple situations. Two extraction procedures with soft (solid–liquid extraction, SLE) and intense (pressurised liquid extraction, PLE) extraction power were used to determine the total concentration of PAH in soils. Results obtained showed that soil properties affect the effectiveness of the extraction procedures tested. The validation of PAH extraction procedure with a reference soil did not confirm that the procedure was adequate for all kinds of soil. Results showed that OM content and clay were the main soil characteristics that should be taken into account to select the most adequate PAH extraction procedure for any given polluted soil.

Quantification of Cr(VI) in soil samples from a contaminated area in northern Italy by isotope dilution mass spectrometry

The aims of the work were to detect and quantify hexavalent chromium in 14 soil samples from an area in Lombardia (northern Italy) contaminated by two polluted water plumes. Cr(VI) was extracted from the solid samples by applying focused microwaves in an alkaline medium after Cr(III) complexation with EDTA. Cr(VI) was reduced to Cr(III) when previously reported extraction conditions for the analysis of certified reference materials were used, and Cr(VI) could not be reliably quantified in the soil samples. The influence of organic matter and iron contents in the samples on the reduction of Cr(VI) was subsequently studied using a new set of soil samples with different iron and organic matter concentrations. Isotope dilution mass spectrometry (IDMS) measured two different enriched stable isotopes of Cr (54 and 53) to evaluate the reduction extent of hexavalent chromium during the analytical procedure. The extraction conditions were optimized to obtain the lowest amount of Cr(VI) reduction and quantify Cr(VI) in the polluted soil samples from Lombardia.

Enhanced Degradation of Petroleum Hydrocarbons in Corn-Steep-Liquor-Treated Soil Microcosm

The efficiency of corn steep liquor (CSL) as a potential stimulant for remediation of hydrocarbon-contaminated soil was evaluated in soil microcosms. Chronically polluted soil samples treated with CSL, water, and un untreated control were compared over a period of 42 days. There were remarkable changes in the physicochemical status of the soil in the CSL-treated set-up with noticeable utilization of essential nutrients such as nitrogen, phosphorus, and potassium. Percentage hydrocarbon utilizers showed a concomitant increase with hydrocarbon utilization in CSL-treated (0.05–0.16%) and water-treated (0.02–0.12%) set-ups, while no significant changes occurred in the untreated control. Gas chromatographic fingerprints showed complete disappearance of the lower-fraction alkanes C7, C8, C9, and C11 within 21 days, as well as some higher fractions, significantly C16 and C29, in the CSL-treated set-up. In the CSL-treated set-up, 77.9% of hydrocarbon was degraded, while the corresponding values for the water-treated and untreated control were 40.55 and 30.6%, respectively. The percentage aliphatic components degraded differed significantly in the CSL-treated, water-treated, and untreated set-ups. The n-C17/pristane and n-C18/phytane ratios in the CSL-treated set-up were 1.298 and 1.153, respectively, on day 0, but at the end of the treatability period, the values had dropped drastically to 0.182 and 0.585, respectively. The results of this study show that corn steep liquor is a potential material for bioremediation of hydrocarbon-polluted sites.

Effect of cassava mill effluent on biological activity of soil microbial community.

This study assessed the effect of cassava effluent on soil microbiological characteristics and enzymatic activities were investigated in soil samples. Soil properties and heavy metal concentrations were evaluated using standard soil analytical and spectroscopic methods, respectively. The microbiological parameters measured include microbial biomass carbon, basal soil respiration, catalase, urease, dehydrogenase activities and number of culturable aerobic bacteria, fungi and actinomycetes. The pH and temperature regime vary significantly (p < 0.05) throughout the study period. All other physicochemical parameters studied were significantly different (p < 0.05) higher than the control site. Soil organic carbon content gave significant positive correlations with microbial biomass carbon, basal soil respiration, catalase activity and dehydrogenase activity (r = 0.450, 0.461, 0.574 and 0.591 at p < 0.01), respectively. The quantitative analysis of soil microbial density demonstrates a marked decrease in total culturable numbers of the different microbial groups of the polluted soil samples. Soil contamination decreased catalase, urease and dehydrogenase activities. The findings revealed that soil enzymes can be used as indices of soil contamination and bio-indicator of soil quality.

English

A study was carried out in a screen house to determine the bacterial population dynamics in a crude oil soil undergoing bioremediation. The agricultural soil samples were polluted with different concentrations (5, 8 and 11%) of crude oil. Physiochemical and microbiological analyses were carried out on the polluted and unpolluted soil samples at various intervals beginning from two weeks after the pollution of the soil samples to the fourteenth week. The soil samples were found to be acidic (5.40) and rich in phosphorous (26.52 mg/kg). There were no significant differences in the pH, organic matter, sodium, potassium and magnesium of the unpolluted and the polluted soil samples. The microbial loads of the polluted soil samples were lower than the unpolluted soil samples throughout the study. The highest bacterial loads (27.00d&plusmn;2.20, 19.40c&plusmn;1.80, 8.70b&plusmn;0.50 for 5, 8 and 11% crude oil concentration respectively) were observed, when Ewingella americana (bacterium with known crude oil degrading ability) was inoculated into the polluted soil samples. The bacterial species responsible for the bioremediation from the polluted soil samples were identified using conventional techniques. The bacterial species isolated and identified were Pseudomonas aeruginosa, Bacillus subtilis, Bacillus cereus, Proteus vulgaris and Staphylococcus aureus. Bacillus spp has the highest percentage frequency (Bacillus subtilis = 30.95% and Bacillus cereus = 21.43%). The consistent isolation of these bacteria shows that they could survive the crude oil pollution and possibly utilize the crude oil, thereby making the crude oil less harmful to the environment. Key words: Bacteria, bioremediation, bacterial species, crude oil.

Delineating bacterial community structure of polluted soil samples collected from cancer prone belt of Punjab, India.

16S rRNA gene analysis has emerged as one of the valuable tools that are being utilized in investigating the molecular phylogenetic structure of the particular environment. Here, we embarked upon understanding and delineating the molecular phylogeny structure of microbes in polluted soil samples from cancer prone belt of the Punjab, India, which is highly contaminated with herbicide, pesticide and heavy metals. To investigate the bacterial phylogeny structure, a high-molecular weight metagenomic DNA was extracted from the soil samples, followed by PCR amplification, cloning and analysis of the 16S rRNA genes. Study employing 16S rRNA profiling of the community DNA revealed the presence of two major phylums: the Proteobacteria (26.7 %), the Bacteroidetes (11.2 %), and several minor groups, i.e., Acidobacteria (4.2 %), Actinobacteria (4.2 %), Firmicutes (2.8 %), Verrucomicrobia (2.8 %), Gemmatimonadetes (1.4 %) and Chloroflexi (1.4 %). Among the Proteobacteria, we mainly observed the α-Proteobacteria (18.3 %). Nearly, 38 % of the recovered 16S rRNA gene sequences in this study do not share similarity with known culturable bacterial sequences reported in the genebank data base and hence considered to be novel. More interestingly, 16S rRNA gene sequences of archaeal origin (7.0 %) were also recovered that primarily indicate change in their evolution pattern. A phylogenetic tree constructed based on alignment-dependent method revealed the extent of similarity these clones shared with each other, followed by alignment-independent methods that statistically confirmed the sequence variation among the clones. Despite the high level of contamination in the study area, we observed remarkable microbial diversity that mainly includes the Gram-negative bacteria. The presence of more Gram-negative bacteria indicates that they have evolved a robust mechanism to resist and cope up with these pollutants compared to Gram-positive groups. Investigation of the polluted soil samples employing culture-independent approach revealed important bacterial groups which could be engineered for future bioremediation studies.

Comparison of Total DNA Extraction Methods for Microbial Community Form Polluted Soil

Abstract DNA isolation represents the basic and probably the most important step in molecular biology for microbial strains, and even more, for microbial community analyses. Despite the development of molecular protocols for DNA microbial community isolation, there are still many drawbacks dependent of samples composition, and even the commercially available genomic isolation kits have significant limitations in recovering high genomic DNA amounts, especially from soil samples. Our study is aiming to compare and optimize a total microbial community DNA isolation protocol from polluted soil samples, estimating the amount and the purity of genomic DNA per g of soil, versus time requirements for each protocol, taking under consideration that our soil samples have a high content of humic acids. We checked several protocols for total DNA extraction, CTAB based, including a specific Kit for Soil DNA Isolation Kit NorgenBiotek. We estimated the time needed for each protocol, the amount of the DNA per gram of polluted soil, proteins and RNA contamination grade, by spectrophotometric analysis, but also the grade of PCR amplification inhibition. The most efficient method for our soil samples with high content of humic acid, suitable for further molecular analyses was the total DNA microbial community sample retrieved from Sagova et al. (2008) based protocol, with several adjustments. This protocol will be valuable for molecular analysis on microbial community profiling from environmental samples, especially from polluted soils.

Toluene Biodegradation by Novel Bacteria Isolated from Polluted Soil Surrounding Car Body Repair and Spray Painting Workshops

Toluene can enter the environment due to various industrial activities. Toluene exposure may cause serious health risks to human and other living organisms. Thus, removal of toluene from the environment is exceptionally important in toluene-contaminated habitats. The aim of present study was to isolate and characterize toluene-utilizing bacteria from contaminated soil surrounding car body repair and painting workshops in Irbid industrial city, Jordan. Therefore, polluted soil samples (10 g) were transferred to flasks containing 99 ml of Stanier’s medium supplemented with 1% toluene and aerobically incubated at 30°C for 72 h. Subsequently, four morphologically different toluene-utilizing bacteria, designated as T1, T2, T3, and T4, were isolated. The cells of T1, T2 and T3 were Gram-positive, rod-shaped, aerobic, and positive for oxidase and catalase. However, the cells of T4 were Gram-negative, round-shaped, aerobic, negative for oxidase, and positive for catalase. Based on 16S rDNA sequencing data, isolates T1, T2 and T3 had high homology (97% - 98%) with Lysinibacillus boronitolerans, Bacillus subtilis and Rhodococcus pyridinivorans, respectively, whereas the isolate T4 had a homology of 89% with Acinetobacter schindleri, and could represent a distinct lineage within the genus Acinetobacter. The generated 16S rDNA sequences were deposited in GenBank database. After testing different physicochemical conditions, the isolates appeared to grow best at 1% toluene, 30°C and pH 6.8, with the generation times ranged between 8 - 11 h. In conclusion, we reported for the first time the identification of four novel soil bacterial species with the capacity to utilize toluene as sole source of carbon and energy from soil sites surrounding car painting workshops. The beneficial effect of the four isolates in the bioremediation of toluene from toluene polluted soil areas must be examined under in situ and ex situ conditions.

Influence of bioaugmentation on biodegradation of phenanthrene-contaminated soil by earthworm in lab scale.

BackgroundUse of earthworm to eliminate the phenanthrene from the soil (bioaccumulation) is developed as an economical method. Bioaugmentation of microorganism was used for promotion of bioaccumulation by earthworm. The aim of this study was to determine the bioaccumulation or biodegradation of phenanthrene by Eisenia fetida and bacterial consortium in polluted soil.MethodsThe amount of 0.4 kg of the polluted soil in the ratio of 10 and 30 mg phenanthrene per kg of dry soil was transferred into each pot. Afterwards, bacteria and earthworms were added to each pot in separate and combination. The samples were kept under field conditions, and the retention concentrations of phenanthrene were analyzed after 8 weeks.ResultsResults showed that the Eisenia fetida was able to significantly remove phenanthrene from the polluted soil samples. Bioaccumulation and bioaugmentation alone have the removal efficiency of 60.24% and 50.3%, respectively. In the combined mode, phenanthrene removal efficiency was 63.81%.ConclusionsThe current study indicated that the use of earthworms, could improve both phenanthrene bioavailability and microbial activity, which led to enhancing removal of carbon-based pollutants.

Spent engine oil pollution and its effects on selected antioxidants of Telfairia occidentalis leaves (617.9)

Spent Engine Oil (SEO) pollution and its effects on selected antioxidants [Protein oxidation (protein thiol (PSH), glutathione (GSH), and total thiol (TSH)] of Telfaria occidentalis leaves was studied. Soil sample was collected from the farmland in Ohii, Owerri West Local Government Ares of Imo State, Nigeria, weighed and polluted with different volumes of spent engine oil (SEO) to give the various percentage pollutions. The polluted soil samples were poured in several nursery bags. Three viable seeds of Telfaria occidentalis were planted in each. An unpolluted soil sample served as the control for the study. Harvest of the leaves was done after 50 days of planting and taken to the laboratory for the assessment of protein oxidation parameters (protein thiol, glutathione and total thiol) concentrations in each of the sample. Results obtained from protein thiol concentration show that there was a significant difference (P&gt;0.05) between the control sample and the 6% polluted sample. There was a progressive reduction in the protein thiol concentration as the volume of the SEO increased. That obtained for GSH also showed a similar trend. There was no significant difference (P&gt;0.05) between control sample and 1% sample pollution but a significant difference (P&gt;0.05) was observed between 0% and 6%. There was also a progressive reduction in the GSH concentration as the volume of the pollutant increased. The same trend was observed for total thiol (TSH) concentration as the SEO volume increased. The mean values obtained for all the parameters (PSH, GSH and TSH) were found not to be significantly different (p&gt;0.05) These results show that increased pollution of soil by spent engine oil have an effect on the protein oxidation parameters of edible fluted pumpkin (T. occidentalis) leaves in areas where there is indiscriminate dumping of spent oil.Grant Funding Source: NIL

Initial Copper Stress Strengthens the Resistance of Soil Microorganisms to a Subsequent Copper Stress

To improve the prediction of essential ecosystem functioning under future environmental disturbances, it is of significance to identify responses of soil microorganisms to environmental stresses. In this study, we collected polluted soil samples from field plots with eight copper levels ranging from 0 to 3,200 mg Cu kg(-1) soil. Then, the soils with 0 and 3,200 mg Cu kg(-1) were selected to construct a microcosm experiment. Four treatments were set up including Cu0-C and Cu3200-C without further Cu addition, and Cu0-A and Cu3200-A with addition of 57.5 mg Cu kg(-1) soil. We measured substrate-induced respiration (SIR) and potential nitrification rate (PNR). Furthermore, the abundance of bacterial, archaeal 16S rRNA genes, ammonia-oxidizing bacteria and archaea amoA genes were determined through quantitative PCR. The soil microbial communities were investigated by terminal restriction fragment length polymorphism (T-RFLP). For the field samples, the SIR and PNR as well as the abundance of soil microorganisms varied significantly between eight copper levels. Soil microbial communities highly differed between the low and high copper stress. In the microcosm experiment, the PNR and SIR both recovered while the abundance of soil microorganisms varied irregularly during the 90-day incubation. The differences of microbial communities measured by pairwise Bray-Curtis dissimilarities between Cu0-A and Cu0-C on day 0 were significantly higher after subsequent stress than before. However, the differences of microbial communities between Cu3200-A and Cu3200-C on day 0 changed little between after subsequent stress and before. Therefore, initial copper stress could increase the resistance of soil microorganisms to subsequent copper stress.