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Sample records for pollutant degrading soil

  1. Chemotactic selection of pollutant degrading soil bacteria

    DOEpatents

    Hazen, T.C.

    1991-03-04

    A method is described for identifying soil microbial strains which may be bacterial degraders of pollutants. This method includes: Placing a concentration of a pollutant in a substantially closed container; placing the container in a sample of soil for a period of time ranging from one minute to several hours; retrieving the container and collecting its contents; microscopically determining the identity of the bacteria present. Different concentrations of the pollutant can be used to determine which bacteria respond to each concentration. The method can be used for characterizing a polluted site or for looking for naturally occurring biological degraders of the pollutant. Then bacteria identified as degraders of the pollutant and as chemotactically attracted to the pollutant are used to innoculate contaminated soil. To enhance the effect of the bacteria on the pollutant, nutrients are cyclicly provided to the bacteria then withheld to alternately build up the size of the bacterial colony or community and then allow it to degrade the pollutant.

  2. Chemotactic selection of pollutant degrading soil bacteria

    DOEpatents

    Hazen, Terry C.

    1994-01-01

    A method for identifying soil microbial strains which may be bacterial degraders of pollutants comprising the steps of placing a concentration of a pollutant in a substantially closed container, placing the container in a sample of soil for a period of time ranging from one minute to several hours, retrieving the container, collecting the contents of the container, and microscopically determining the identity of the bacteria present. Different concentrations of the pollutant can be used to determine which bacteria respond to each concentration. The method can be used for characterizing a polluted site or for looking for naturally occurring biological degraders of the pollutant. Then bacteria identified as degraders of the pollutant and as chemotactically attracted to the pollutant are used to inoculate contaminated soil. To enhance the effect of the bacteria on the pollutant, nutrients are cyclicly provided to the bacteria then withheld to alternately build up the size of the bacterial colony or community and then allow it to degrade the pollutant.

  3. Method of degrading pollutants in soil

    DOEpatents

    Hazen, Terry C.; Lopez-De-Victoria, Geralyne

    1994-01-01

    A method and system for enhancing the motility of microorganisms by placing an effective amount of chlorinated hydrocarbons, preferably chlorinated alkenes, and most preferably trichloroethylene in spaced relation to the microbes so that the surprisingly strong, monomodal, chemotactic response of the chlorinated hydrocarbon on subsurface microbes can draw the microbes away from or towards and into a substance, as desired. In remediation of groundwater pollution, for example, TCE can be injected into the plume to increase the population of microbes at the plume whereby the plume can be more quickly degraded. A TCE-degrading microbe, such as Welchia alkenophilia, can be used to degrade the TCE following the degradation of the original pollutant.

  4. Method of degrading pollutants in soil

    DOEpatents

    Hazen, T.C.; Lopez-De-Victoria, G.

    1994-07-05

    Disclosed are a method and system for enhancing the motility of microorganisms. This is accomplished by placing an effective amount of chlorinated hydrocarbons, preferably chlorinated alkenes, and most preferably trichloroethylene in spaced relation to the microbes so that the surprisingly strong, monomodal, chemotactic response of the chlorinated hydrocarbon on subsurface microbes can draw the microbes away from or towards and into a substance, as desired. In remediation of groundwater pollution, for example, TCE can be injected into the plume to increase the population of microbes at the plume whereby the plume can be more quickly degraded. A TCE-degrading microbe, such as Welchia alkenophilia, can be used to degrade the TCE following the degradation of the original pollutant. 5 figures.

  5. Degradation of Polycyclic Aromatic Hydrocarbons (PAHs) by Bacteria Isolated from Light Oil Polluted Soils

    NASA Astrophysics Data System (ADS)

    Ohnuma, T.; Suto, K.; Inoue, C.

    2007-03-01

    Polycyclic aromatic hydrocarbons (PAHs) have polluted soil and groundwater widely and for long term because of their low solubility at normal temperature. Several microorganisms, such as Pseudomonas sp., Sphigomonas sp., a white-rot fungus and so on, being able to decompose PAHs, have been isolated and researched. This study reported to investigate biodegradation of low molecule PAH by isolated bacteria from light oil polluted soil. 12 isolates were obtained from a light oil polluted soil using naphthalene, fluorene and anthracene as sole carbon source, of which 4 isolates grew with naphthalene, 4 isolates did with fluorene and 4 isolates did with anthracene. Among them 3 isolates showed the ability to degrade phenanthrene additionally. These phenanthrene degradation and growth rates were almost same as that of S. yanoikuyae (DSM6900), which is the typical bacteria of PAHs degrader. Therefore, the isolate seemed to have an expectation for PAHs degradation.

  6. Comparative assessment of bioremediation approaches to highly recalcitrant PAH degradation in a real industrial polluted soil.

    PubMed

    Lladó, S; Covino, S; Solanas, A M; Viñas, M; Petruccioli, M; D'annibale, A

    2013-03-15

    High recalcitrant characteristics and low bioavailability rates due to aging processes can hinder high molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs) bioremediation in real industrial polluted soils. With the aim of reducing the residual fraction of total petroleum hydrocarbons (TPH) and (HMW-PAHs) in creosote-contaminated soil remaining after a 180-d treatment in a pilot-scale biopile, either biostimulation (BS) of indigenous microbial populations with a lignocellulosic substrate (LS) or fungal bioaugmentation with two strains of white-rot fungi (WRF) (i.e., Trametes versicolor and Lentinus tigrinus) were comparatively tested. The impact of bivalent manganese ions and two mobilizing agents (MAs) (i.e., Soybean Oil and Brij 30) on the degradation performances of biostimulated and bioaugmented microcosms was also compared. The results reveal soil colonization by both WRF strains was clearly hampered by an active native soil microbiota. In fact, a proper enhancement of native microbiota by means of LS amendment promoted the highest biodegradation of HMW-PAHs, even of those with five aromatic rings after 60 days of treatment, but HMW-PAH-degrading bacteria were specifically inhibited when non-ionic surfactant Brij 30 was amended. Effects of bioaugmentation and other additives such as non-ionic surfactants on the degrading capability of autochthonous soil microbiota should be evaluated in polluted soils before scaling up the remediation process at field scale.

  7. Effect of electric intensity on the microbial degradation of petroleum pollutants in soil.

    PubMed

    Li, Tingting; Guo, Shuhai; Wu, Bo; Li, Fengmei; Niu, Zhixin

    2010-01-01

    Electro-bioremediation is an innovative method to remedy organic-polluted soil. However, the principle of electrokinetic technology enhancing the function of microbes, especially the relationship of electric intensity and biodegradation efficiency, is poorly investigated. Petroleum was employed as a target organic pollutant at a level of 50 g/kg (mass of petroleum/mass of dry soil). A direct current power supply was used for tests with a constant direct current electric voltage (1.0 V/cm). The petroleum concentrations were measured at 3275-3285 nm after extraction using hexane, the group composition of crude oil was analyzed by column chromatography. The water content of soil was kept 25% (m/m). The results indicated the degradation process was divided into two periods: from day 1 to day 40, from day 41 to day 100. The treatment of soil with an appropriate electric field led the bacteria to have a persistent effect in the whole period of 100 days. The highest biodegradation efficiency of 45.5% was obtained after treatment with electric current and bacteria. The electric-bioremediation had a positive effect on alkane degradation. The degradation rate of alkane was 1.6 times higher in the soil exposed to electric current than that treated with bacteria for 100 days. A proper direct current could stimulate the microbial activities and accelerate the biodegradation of petroleum. There was a positive correlation between the electric intensities and the petroleum bioremediation efficiencies with a coefficient of 0.9599.

  8. A previously unexposed forest soil microbial community degrades high levels of the pollutant 2,4,6-trichlorophenol.

    PubMed

    Sánchez, M A; Vásquez, M; González, B

    2004-12-01

    2,4,6-trichlorophenol (2,4,6-TCP) is a hazardous pollutant that is efficiently degraded by some aerobic soil bacterial isolates under laboratory conditions. The degradation of this pollutant in soils and its effect on the soil microbial community are poorly understood. We report here the ability of a previously unexposed forest soil microbiota to degrade high levels of 2,4,6-TCP and describe the changes in the soil microbial community found by terminal restriction fragment length polymorphism (T-RFLP) analysis. After 30 days of incubation, about 50% degradation of this pollutant was observed in soils amended with 50 to 5,000 ppm of 2,4,6-TCP. The T-RFLP analysis showed that the soil bacterial community was essentially unchanged after exposure to up to 500 ppm of 2,4,6-TCP. However, a significant decrease in richness was found with 2,000 and 5,000 ppm of 2,4,6-TCP, even though the removal of this pollutant remained high. The introduction of Ralstonia eutropha JMP134 or R. eutropha MS1, two efficient 2,4,6-TCP degraders, to this soil did not improve degradation of this pollutant, supporting the significant bioremediation potential of this previously unexposed, endogenous forest soil microbial community.

  9. Importance of soil organic matter for the diversity of microorganisms involved in the degradation of organic pollutants

    PubMed Central

    Neumann, Dominik; Heuer, Anke; Hemkemeyer, Michael; Martens, Rainer; Tebbe, Christoph C

    2014-01-01

    Many organic pollutants are readily degradable by microorganisms in soil, but the importance of soil organic matter for their transformation by specific microbial taxa is unknown. In this study, sorption and microbial degradation of phenol and 2,4-dichlorophenol (DCP) were characterized in three soil variants, generated by different long-term fertilization regimes. Compared with a non-fertilized control (NIL), a mineral-fertilized NPK variant showed 19% and a farmyard manure treated FYM variant 46% more soil organic carbon (SOC). Phenol sorption declined with overall increasing SOC because of altered affinities to the clay fraction (soil particles <2 mm in diameter). In contrast, DCP sorption correlated positively with particulate soil organic matter (present in the soil particle fractions of 63–2000 μm). Stable isotope probing identified Rhodococcus, Arthrobacter (both Actinobacteria) and Cryptococcus (Basidiomycota) as the main degraders of phenol. Rhodococcus and Cryptococcus were not affected by SOC, but the participation of Arthrobacter declined in NPK and even more in FYM. 14C-DCP was hardly metabolized in the NIL variant, more efficiently in FYM and most in NPK. In NPK, Burkholderia was the main degrader and in FYM Variovorax. This study demonstrates a strong effect of SOC on the partitioning of organic pollutants to soil particle size fractions and indicates the profound consequences that this process could have for the diversity of bacteria involved in their degradation. PMID:24430482

  10. Importance of soil organic matter for the diversity of microorganisms involved in the degradation of organic pollutants.

    PubMed

    Neumann, Dominik; Heuer, Anke; Hemkemeyer, Michael; Martens, Rainer; Tebbe, Christoph C

    2014-06-01

    Many organic pollutants are readily degradable by microorganisms in soil, but the importance of soil organic matter for their transformation by specific microbial taxa is unknown. In this study, sorption and microbial degradation of phenol and 2,4-dichlorophenol (DCP) were characterized in three soil variants, generated by different long-term fertilization regimes. Compared with a non-fertilized control (NIL), a mineral-fertilized NPK variant showed 19% and a farmyard manure treated FYM variant 46% more soil organic carbon (SOC). Phenol sorption declined with overall increasing SOC because of altered affinities to the clay fraction (soil particles <2 mm in diameter). In contrast, DCP sorption correlated positively with particulate soil organic matter (present in the soil particle fractions of 63-2000 μm). Stable isotope probing identified Rhodococcus, Arthrobacter (both Actinobacteria) and Cryptococcus (Basidiomycota) as the main degraders of phenol. Rhodococcus and Cryptococcus were not affected by SOC, but the participation of Arthrobacter declined in NPK and even more in FYM. (14)C-DCP was hardly metabolized in the NIL variant, more efficiently in FYM and most in NPK. In NPK, Burkholderia was the main degrader and in FYM Variovorax. This study demonstrates a strong effect of SOC on the partitioning of organic pollutants to soil particle size fractions and indicates the profound consequences that this process could have for the diversity of bacteria involved in their degradation.

  11. Starch-enhanced degradation of HMW PAHs by Fusarium sp. in an aged polluted soil from a coal mining area.

    PubMed

    Zhao, Ou-Ya; Zhang, Xue-Na; Feng, Sheng-Dong; Zhang, Li-Xiu; Shi, Wei; Yang, Zhi-Xin; Chena, Miao-Miao; Fanga, Xue-Dan

    2017-05-01

    The present study used strain ZH-H2 (Fusarium sp.) isolated by our group as the PAH-degrading strain and 5-6-rings PAHs as degradation objects. The soil incubation experiment was carried out to investigate the starch-enhanced degradation effects of HMW PAHs by Fusarium sp. in an Aged Polluted Soil from a Coal Mining Area. The results showed that the removal rates of BaP, InP and BghiP increased with increasing inoculation rate of ZH-H2 in the unsterile aged polluted soil of coal mining area, with the exception of BbF degradation which increased in the H2 treatment and then decreased. Different addition dosage of starch apparently resulted in degradation of 4 PAHs in soil, with removal rates of 14.47% for BaP, 23.83% for DbA, 30.77% for BghiP and 31.00% for InP obtained with treatment D2, respectively higher than in treatment D1. So starch addition apparently enhanced the degradation of the 4 PAHs, especially InP and BghiP, by native microbes in the aged HMW PAH-polluted soil. By adding starch to these aged polluted soils with inoculated strain ZH-H2, HMW-PAHs degradation was further improved and addition of 0.5 g kg(-1) starch to soils with 1.0 g kg(-1) Fusarium ZH-H2 (D2 + H2) performed best to the 4 HMW-PAHs in all of these combination treatments by a factor of up to 3.09, depending on the PAH. We found that the highest polyphenol oxidase activities under D2 + H2 treatments are consistent with the results of removal rates of 4 PAHs. Our findings suggest that the combination of Fusarium sp. ZH-H2 and starch offers a suitable alternative for bioremediation of aged PAH-contaminated soil in coal mining areas, with a recommended inoculation size of 0.5 g Fusarium sp. ZH-H2 and addition of 0.5 g kg(-1) starch per kg soil. Copyright © 2016. Published by Elsevier Ltd.

  12. Bioremediation of multi-polluted soil by spent mushroom (Agaricus bisporus) substrate: Polycyclic aromatic hydrocarbons degradation and Pb availability.

    PubMed

    García-Delgado, Carlos; Yunta, Felipe; Eymar, Enrique

    2015-12-30

    This study investigates the effect of three spent Agaricus bisporus substrate (SAS) application methods on bioremediation of soil multi-polluted with Pb and PAH from close to a shooting range with respect natural attenuation (SM). The remediation treatments involve (i) use of sterilized SAS to biostimulate the inherent soil microbiota (SSAS) and two bioaugmentation possibilities (ii) its use without previous treatment to inoculate A. bisporus and inherent microbiota (SAS) or (iii) SAS sterilization and further A. bisporus re-inoculation (Abisp). The efficiency of each bioremediation microcosm was evaluated by: fungal activity, heterotrophic and PAH-degrading bacterial population, PAH removal, Pb mobility and soil eco-toxicity. Biostimulation of the native soil microbiology (SSAS) achieved similar levels of PAH biodegradation as SM and poor soil detoxification. Bioaugmented microcosms produced higher PAH removal and eco-toxicity reduction via different routes. SAS increased the PAH-degrading bacterial population, but lowered fungal activity. Abisp was a good inoculum carrier for A. bisporus exhibiting high levels of ligninolytic activity, the total and PAH-degrading bacteria population increased with incubation time. The three SAS applications produced slight Pb mobilization (<0.3%). SAS sterilization and further A. bisporus re-inoculation (Abisp) proved the best application method to remove PAH, mainly BaP, and detoxify the multi-polluted soil.

  13. Synergistic action of rhizospheric fungi with Megathyrsus maximus root speeds up hydrocarbon degradation kinetics in oil polluted soil.

    PubMed

    Asemoloye, Michael Dare; Ahmad, Rafiq; Jonathan, Segun Gbolagade

    2017-11-01

    This study was aimed at combining the potentials of plant and some rhizospheric fungal strains in remediation of crude-oil polluted soil. Four new rhizospheric fungi were identified from an aged crude-oil polluted site and used with Megathyrsus maximus (guinea grass) for a 90 day synergistic remediation experiment. Cultures of these strains were first mixed with spent mushroom compost (SMC), the mixture was then applied to a sterilized crude oil polluted soil at concentrations of 10%, 20%, 30% and 40% potted in three replicates. Soil with plant alone (0%1) and soil with fungi-SMC alone (0%2) served as controls. The soil's initial and final pH, nutrient, 16 EPA PAHs and heavy metal contents were determined, degradation rate, half-life and percentage loss of the total polyaromatic hydrocarbon (TPAH) were also calculated. Finally, the remediated soils were further screened for seed germination supporting index. The fungal strains were identified and registered at NCBI as Aspergillus niger asemoA (KY473958.1), Talaromyces purpurogenus asemoF (KY488463.1), Trichoderma harzianum asemoJ (KY488466.1) and Aspergillus flavus asemoM (KY488467.1). We observed for the first time that the synergistic mechanism improved the soil nutrient, reduced the heavy metal concentration and sped up hydrocarbon degradation rate. Using the initial and final concentrations of the TPAH, we recorded highest biodegradation rates (K1) and half-life (t1/2) in 30 and 40% treatments over controls, these treatments also had highest seed germination supporting index. This work suggests that the set-up synergistic remediation could be used to remediate crude oil polluted soil and this could be used in large scale. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Coal mining activities change plant community structure due to air pollution and soil degradation.

    PubMed

    Pandey, Bhanu; Agrawal, Madhoolika; Singh, Siddharth

    2014-10-01

    The aim of this study was to investigate the effects of coal mining activities on the community structures of woody and herbaceous plants. The response of individual plants of community to defilement caused by coal mining was also assessed. Air monitoring, soil physico-chemical and phytosociological analyses were carried around Jharia coalfield (JCF) and Raniganj coalfield. The importance value index of sensitive species minified and those of tolerant species enhanced with increasing pollution load and altered soil quality around coal mining areas. Although the species richness of woody and herbaceous plants decreased with higher pollution load, a large number of species acclimatized to the stress caused by the coal mining activities. Woody plant community at JCF was more affected by coal mining than herbaceous community. Canonical correspondence analysis revealed that structure of herbaceous community was mainly driven by soil total organic carbon, soil nitrogen, whereas woody layer community was influenced by sulphur dioxide in ambient air, soil sulphate and soil phosphorus. The changes in species diversity observed at mining areas indicated an increase in the proportion of resistant herbs and grasses showing a tendency towards a definite selection strategy of ecosystem in response to air pollution and altered soil characteristics.

  15. Evident bacterial community changes but only slight degradation when polluted with pyrene in a red soil

    PubMed Central

    Ren, Gaidi; Ren, Wenjie; Teng, Ying; Li, Zhengao

    2015-01-01

    Understanding the potential for Polycyclic aromatic hydrocarbons (PAH) degradation by indigenous microbiota and the influence of PAHs on native microbial communities is of great importance for bioremediation and ecological evaluation. Various studies have focused on the bacterial communities in the environment where obvious PAH degradation was observed, little is known about the microbiota in the soil where poor degradation was observed. Soil microcosms were constructed with a red soil by supplementation with a high-molecular-weight PAH (pyrene) at three dosages (5, 30, and 70 mg ⋅ kg-1). Real-time PCR was used to evaluate the changes in bacterial abundance and pyrene dioxygenase gene (nidA) quantity. Illumina sequencing was used to investigate changes in diversity, structure, and composition of bacterial communities. After 42 days of incubation, no evident degradation was observed. The poor degradation ability was associated with the stability or significant decrease of abundance of the nidA gene. Although the abundance of the bacterial 16S rRNA gene was not affected by pyrene, the bacterial richness and diversity were decreased with increasing dosage of pyrene and the community structure was changed. Phylotypes affected by pyrene were comprehensively surveyed: (1) at the high taxonomic level, seven of the abundant phyla/classes (relative abundance >1.0%) including Chloroflexi, AD3, WPS-2, GAL5, Alphaproteobacteria, Actinobacteria, and Deltaproteobacteria and one rare phylum Crenarchaeota were significantly decreased by at least one dosage of pyrene, while three phyla/classes (Acidobacteria, Betaproteobacteria, and Gammaproteobacteria) were significantly increased; and (2) at the lower taxonomic level, the relative abundances of twelve orders were significantly depressed, whereas those of nine orders were significantly increased. This work enhanced our understanding of the biodegradation potential of pyrene in red soil and the effect of pyrene on soil ecosystems

  16. Degradation and resilience of soils

    PubMed Central

    Lal, R.

    1997-01-01

    Debate on global soil degradation, its extent and agronomic impact, can only be resolved through understanding of the processes and factors leading to establishment of the cause-effect relationships for major soils, ecoregions, and land uses. Systematic evaluation through long-term experimentation is needed for establishing quantitative criteria of (i) soil quality in relation to specific functions; (ii) soil degradation in relation to critical limits of key soil properties and processes; and (iii) soil resilience in relation to the ease of restoration through judicious management and discriminate use of essential input. Quantitative assessment of soil degradation can be obtained by evaluating its impact on productivity for different land uses and management systems. Interdisciplinary research is needed to quantify soil degradation effects on decrease in productivity, reduction in biomass, and decline in environment quality throught pollution and eutrophication of natural waters and emission of radiatively-active gases from terrestrial ecosystems to the atmosphere. Data from long-term field experiments in principal ecoregions are specifically needed to (i) establish relationships between soil quality versus soil degradation and soil quality versus soil resilience; (ii) identify indicators of soil quality and soil resilience; and (iii) establish critical limits of important properties for soil degradation and soil resilience. There is a need to develop and standardize techniques for measuring soil resilience.

  17. Root exudates modify bacterial diversity of phenanthrene degraders in PAH-polluted soil but not phenanthrene degradation rates.

    PubMed

    Cébron, Aurélie; Louvel, Brice; Faure, Pierre; France-Lanord, Christian; Chen, Yin; Murrell, J Colin; Leyval, Corinne

    2011-03-01

    To determine whether the diversity of phenanthrene-degrading bacteria in an aged polycyclic aromatic hydrocarbon (PAH) contaminated soil is affected by the addition of plant root exudates, DNA stable isotope probing (SIP) was used. Microcosms of soil with and without addition of ryegrass exudates and with ¹³C-labelled phenanthrene (PHE) were monitored over 12 days. PHE degradation was slightly delayed in the presence of added exudate after 4 days of incubation. After 12 days, 68% of added PHE disappeared both with and without exudate. Carbon balance using isotopic analyses indicated that a part of the ¹³C-PHE was not totally mineralized as ¹³CO₂ but unidentified ¹³C-compounds (i.e. ¹³C-PHE or ¹³C-labelled metabolites) were trapped into the soil matrix. Temporal thermal gradient gel electrophoresis (TTGE) analyses of 16S rRNA genes were performed on recovered ¹³C-enriched DNA fractions. 16S rRNA gene banding showed the impact of root exudates on diversity of PHE-degrading bacteria. With PHE as a fresh sole carbon source, Pseudoxanthomonas sp. and Microbacterium sp. were the major PHE degraders, while in the presence of exudates, Pseudomonas sp. and Arthrobacter sp. were favoured. These two different PHE-degrading bacterial populations were also distinguished through detection of PAH-ring hydroxylating dioxygenase (PAH-RHD(α)) genes by real-time PCR. Root exudates favoured the development of a higher diversity of bacteria and increased the abundance of bacteria containing known PAH-RHD(α) genes.

  18. Influence of operational parameters on electro-Fenton degradation of organic pollutants from soil.

    PubMed

    Rosales, E; Pazos, M; Longo, M A; Sanroman, M A

    2009-09-01

    The combination of the Fenton's reagent with electrochemistry (the electro-Fenton process) represents an efficient method for wastewater treatment. This study describes the use of this process to clean soil or clay contaminated by organic compounds. Model soil of kaolinite clay polluted with the dye Lissamine Green B (LGB) was used to evaluate the capability of the electro-Fenton process. The effects of operating parameters such as electrode material and dye concentration were investigated. Operating in an electrochemical cell under optimized conditions while using electrodes of graphite, a constant potential difference of 5 V, pH 3, 0.2 mM FeSO(4). 7H(2)O, and electrolyte 0.1 M Na(2)SO(4), around 80% of the LGB dye on kaolinite clay was decolorized after 3 hours with an electric power consumption around 0.15 W h g(-1). Furthermore, the efficiency of this process for the remediation of a real soil polluted with phenanthrene, a typical polycyclic aromatic hydrocarbon, has been demonstrated.

  19. Exploring the potential of fungi isolated from PAH-polluted soil as a source of xenobiotics-degrading fungi.

    PubMed

    Godoy, Patricia; Reina, Rocío; Calderón, Andrea; Wittich, Regina-Michaela; García-Romera, Inmaculada; Aranda, Elisabet

    2016-10-01

    The aim of this study was to find polycyclic aromatic hydrocarbon (PAH)-degrading fungi adapted to polluted environments for further application in bioremediation processes. In this study, a total of 23 fungal species were isolated from a historically pyrogenic PAH-polluted soil in Spain and taxonomically identified. The dominant groups in these samples were the ones associated with fungi belonging to the Ascomycota phylum and two isolates belonging to the Mucoromycotina subphylum and Basiodiomycota phylum. We tested their ability to convert the three-ring PAH anthracene in a 42-day time course and analysed their ability to secrete extracellular oxidoreductase enzymes. Among the 23 fungal species screened, 12 were able to oxidize anthracene, leading to the formation of 9,10-anthraquinone as the main metabolite, a less toxic one than the parent compound. The complete removal of anthracene was achieved by three fungal species. In the case of Scopulariopsis brevicaulis, extracellular enzyme independent degradation of the initial 100 μM anthracene occurred, whilst in the case of the ligninolytic fungus Fomes (Basidiomycota), the same result was obtained with extracellular enzyme-dependent transformation. The yield of accumulated 9,10-anthraquinone was 80 and 91 %, respectively, and Fomes sp. could slowly deplete it from the growth medium when offered alone. These results are indicative for the effectiveness of these fungi for pollutant removal. Graphical abstract ᅟ.

  20. Photocatalytic degradation of chlorophenols in soil washing wastes containing Brij 35. Correlation between the degradation kinetics and the pollutants-micelle binding.

    PubMed

    Davezza, M; Fabbri, D; Pramauro, E; Prevot, A Bianco

    2013-05-01

    The photocatalytic degradations of 4-chlorophenol (CP), 4-chloro-2-methylphenol (CMP), 4-chloro-3,5-dimethylphenol (CDMP) and 4-chloro-2-isopropyl-5-methylphenol (CIMP) were investigated in water and in simulated soil washing wastes containing Brij 35 (polyoxyethylene(23)dodecyl ether) in the presence of TiO2 dispersions. A neat inhibition of substrate decomposition proportional to their growing hydrophobicity was observed in the washing wastes for CP, CMP and CDMP, whereas CIMP showed a different behaviour. The mineralization of the organic chlorine of CP and CIMP was relatively fast and complete, whereas it was much slower for CMP and CDMP. Micellar solubilization and substrate adsorption onto the semiconductor play opposite roles on the degradation kinetics, and a breakpoint between the corresponding induced effects was evidenced when the pollutants become completely bound to the micellar aggregates.

  1. Impact of soil structure heterogeneity on the degradation of organic pollutants at the centimeter scale : 3D Modeling using graph based method

    NASA Astrophysics Data System (ADS)

    Sinclair Yemini, Francis; Chenu, Claire; Monga, Olivier; Vieuble Gonond, Laure; Juarez, Sabrina; Pihneiro, Marc; otten, Wilfred; Garnier, Patricia

    2014-05-01

    Contaminant degradation by microorganisms is very variable in soils because of the very heterogeneous spatial relationship of contaminant/degraders. Repacked Soil columns were carried out to study the degradation of 2,4D pesticide labelled with C14 for different scenarios of microorganisms and pesticide initial location. Measurements of global C14-CO2 emission and C14 distribution in the soil column showed that the initial location play a crucial rule on the dissipation of the pollutant. Experiments were simulated using a 3D model able to model microbial degradation and substrate diffusion between aggregates by considering explicitly the 3D structure of soil from CT images. The initial version of the model (Monga et al., 2008) was improved in order to simulate diffusion in samples of large size. Partial differential equations were implemented using freefem++ solver. The model simulates properly the dynamics of 2,4D in the column for the different initial situations. CT images of the same soil but using undisturbed structure instead of repacked aggregates were also carried out. Significant differences of the simulated results were observed between the repacked and the undisturbed soil. The conclusion of our work is that the heterogeneity of the soil structure and location of pollutants and decomposers has a very strong influence on the dissipation of pollutants.

  2. Degradation and remediation of soils polluted with oil-field wastewater

    NASA Astrophysics Data System (ADS)

    Gabbasova, I. M.; Suleymanov, R. R.; Garipov, T. T.

    2013-02-01

    The changes in the properties of gray forest soils and leached chernozems under the impact of contamination with highly saline oil-field wastewater were studied in a model experiment. It was shown that the soil contamination results in the development of technogenic salinization and alkalization leading to worsening of the major soil properties. The salinization of the soils with oil-field wastewater transformed the soil exchange complex: the cation exchange capacity decreased, and the exchangeable sodium percentage increased to up to 25% of the CEC upon the wastewater infiltration and up to 60% of the CEC upon the continuous soil saturation with the wastewater independently of the soil type. The content of exchangeable magnesium also increased due to the phenomenon of super-equivalent exchange. Despite the saturation of the soil adsorption complex with sodium, no development of the soil alkalization took place in the presence of the high concentration of soluble salts. However, the soil alkalization was observed upon the soil washing from soluble salts. The gypsum application to the washed soils lowered the exchangeable sodium concentration to acceptable values and normalized the soil reaction. The gypsum application without the preliminary washing of the soils from soluble salts was of low efficiency; even after six months, the content of exchangeable sodium remained very high. The subsequent soil washing resulted in the removal of the soluble salts but did not affect the degree of the soil alkalization.

  3. Earthworms and Soil Pollutants

    PubMed Central

    Hirano, Takeshi; Tamae, Kazuyoshi

    2011-01-01

    Although the toxicity of metal contaminated soils has been assessed with various bioassays, more information is needed about the biochemical responses, which may help to elucidate the mechanisms involved in metal toxicity. We previously reported that the earthworm, Eisenia fetida, accumulates cadmium in its seminal vesicles. The bio-accumulative ability of earthworms is well known, and thus the earthworm could be a useful living organism for the bio-monitoring of soil pollution. In this short review, we describe recent studies concerning the relationship between earthworms and soil pollutants, and discuss the possibility of using the earthworm as a bio-monitoring organism for soil pollution. PMID:22247659

  4. [Isolation and identification of a PAHs-degrading strain Gordonia sp. He4 and its dynamics during bioremediation of phenanthrene polluted soil].

    PubMed

    Liu, Lei; Li, Xi-Wu; Liu, Shuang-Jiang; Liu, Zhi-Pei

    2007-03-01

    A bacterial strain, He4, capable of degrading n-hexadecane and other polycyclic aromatic compounds was isolated from petroleum polluted soil. This strain was identified as Gordonia sp. He4 according to its morphology, physiological, biochemical properties and the analysis of its 16S rRNA gene sequence. Based on its 16S rRNA gene sequence, specific primers were designed and a competitor template was amplified by PCR. The dynamics of strain He4 in phenanthrene polluted soil was analyzed by colony forming unit (CFU) method and QC-PCR method. The results showed that partial of He4 become non-culturable and un-detectable by CFU method. But by using QC-PCR, the population density of strain He4 could be measured accurately.

  5. Assessment of degradation potential of aliphatic hydrocarbons by autochthonous filamentous fungi from a historically polluted clay soil.

    PubMed

    Covino, Stefano; D'Annibale, Alessandro; Stazi, Silvia Rita; Cajthaml, Tomas; Čvančarová, Monika; Stella, Tatiana; Petruccioli, Maurizio

    2015-02-01

    The present work was aimed at isolating and identifying the main members of the mycobiota of a clay soil historically contaminated by mid- and long-chain aliphatic hydrocarbons (AH) and to subsequently assess their hydrocarbon-degrading ability. All the isolates were Ascomycetes and, among them, the most interesting was Pseudoallescheria sp. 18A, which displayed both the ability to use AH as the sole carbon source and to profusely colonize a wheat straw:poplar wood chip (70:30, w/w) lignocellulosic mixture (LM) selected as the amendment for subsequent soil remediation microcosms. After a 60 d mycoaugmentation with Pseudoallescheria sp. of the aforementioned soil, mixed with the sterile LM (5:1 mass ratio), a 79.7% AH reduction and a significant detoxification, inferred by a drop in mortality of Folsomia candida from 90 to 24%, were observed. However, similar degradation and detoxification outcomes were found in the non-inoculated incubation control soil that had been amended with the sterile LM. This was due to the biostimulation exerted by the amendment on the resident microbiota, fungi in particular, the activity and density of which were low, instead, in the non-amended incubation control soil. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Decontaminating soil organic pollutants with manufactured nanoparticles.

    PubMed

    Li, Qi; Chen, Xijuan; Zhuang, Jie; Chen, Xin

    2016-06-01

    Organic pollutants in soils might threaten the environmental and human health. Manufactured nanoparticles are capable to reduce this risk efficiently due to their relatively large capacity of sorption and degradation of organic pollutants. Stability, mobility, and reactivity of nanoparticles are prerequisites for their efficacy in soil remediation. On the basis of a brief introduction of these issues, this review provides a comprehensive summary of the application and effectiveness of various types of manufactured nanoparticles for removing organic pollutants from soil. The main categories of nanoparticles include iron (oxides), titanium dioxide, carbonaceous, palladium, and amphiphilic polymeric nanoparticles. Their advantages (e.g., unique properties and high sorption capacity) and disadvantages (e.g., high cost and low recovery) for soil remediation are discussed with respect to the characteristics of organic pollutants. The factors that influence the decontamination effects, such as properties, surfactants, solution chemistry, and soil organic matter, are addressed.

  7. Oil degradation in soil.

    PubMed Central

    Raymond, R L; Hudson, J O; Jamison, V W

    1976-01-01

    The environmental effects of adding certain selected petroleum products to field soils at widely separated geographical locations under optimum conditions for biodegradation were studied. The locations selected for study of soil biodegradation of six oils (used crankcase oil from cars, used crankcase oil from trucks, an Arabian Heavy crude oil, a Coastal Mix crude oil, a home heating oil no. 2, and a residual fuel oil no. 6) were Marcus Hook, Pennsylvania, Tulsa, Oklahoma, and Corpus Christi, Texas. The investigative process, covering a period of 1 year at each location, was conducted in 14 fields plots (1.7 by 3.0 m) to which the oils were added in a single application at a rate of 11.9 m3/4 X 10(3) m2. One-half of the plots at each location were fertilized, and the incorporation of the oils and fertilizers was accomplished with rototillers to a depth of 10 to 15 cm. Concentrations of all oils decreased significantly at all locations. The average reduction ranged from 48.5 to 90.0% depending upon the type of oil and location. Rates of degradation did not exceed 2.4 m3/4 X 10(3) m2 per month. Compositional changes in the oil with time were investigated using silica gel fractionation, gas chromatography, and ultraviolet absorbance. With the possible exception of the two fuel oils, the compositional changes were generally in the same direction for all of the oils. The silica gel fractionation and gravimetric data on residual oils show that all classes of compounds were degraded, but the more polar type degrade more slowly. Analysis of runoff water, leachate, and soils indicated that at the concentration applied no oil less was observed from these plots via water movement. No significant movement of lead compounds added to the soils in the used crankcase oils was observed. Significant increases in hydrocarbon-utilizing microorganisms were demonstrated in all treated plots using either the pure hydrocarbon, n-hexadecane, or the applied oils as the growth substrate

  8. Oil degradation in soil.

    PubMed

    Raymond, R L; Hudson, J O; Jamison, V W

    1976-04-01

    The environmental effects of adding certain selected petroleum products to field soils at widely separated geographical locations under optimum conditions for biodegradation were studied. The locations selected for study of soil biodegradation of six oils (used crankcase oil from cars, used crankcase oil from trucks, an Arabian Heavy crude oil, a Coastal Mix crude oil, a home heating oil no. 2, and a residual fuel oil no. 6) were Marcus Hook, Pennsylvania, Tulsa, Oklahoma, and Corpus Christi, Texas. The investigative process, covering a period of 1 year at each location, was conducted in 14 fields plots (1.7 by 3.0 m) to which the oils were added in a single application at a rate of 11.9 m3/4 X 10(3) m2. One-half of the plots at each location were fertilized, and the incorporation of the oils and fertilizers was accomplished with rototillers to a depth of 10 to 15 cm. Concentrations of all oils decreased significantly at all locations. The average reduction ranged from 48.5 to 90.0% depending upon the type of oil and location. Rates of degradation did not exceed 2.4 m3/4 X 10(3) m2 per month. Compositional changes in the oil with time were investigated using silica gel fractionation, gas chromatography, and ultraviolet absorbance. With the possible exception of the two fuel oils, the compositional changes were generally in the same direction for all of the oils. The silica gel fractionation and gravimetric data on residual oils show that all classes of compounds were degraded, but the more polar type degrade more slowly. Analysis of runoff water, leachate, and soils indicated that at the concentration applied no oil less was observed from these plots via water movement. No significant movement of lead compounds added to the soils in the used crankcase oils was observed. Significant increases in hydrocarbon-utilizing microorganisms were demonstrated in all treated plots using either the pure hydrocarbon, n-hexadecane, or the applied oils as the growth substrate

  9. [Bioremediation of oil-polluted soil with an association including the fungus Pleurotus ostreatus and soil microflora].

    PubMed

    Pozdniakova, N N; Nikitina, V E; Turkovskaia, O V

    2008-01-01

    The possibility of application of the Pleurotus ostreatus D1-soil microflora to bioremediation of oil-polluted soils was studied. The fungus degraded mainly the aromatic fraction, whereas soil microflora intensely degraded paraffin and naphthene oil fractions. Introduction of the fungus Pleurotus ostreatus D to soil induces degradation of a wider range of oil hydrocarbons. It is reasonable to further investigate the discovered phenomenon in order to improve procedures of remediation of oil-polluted soils.

  10. Draft Genome Sequence of Nocardioides luteus Strain BAFB, an Alkane-Degrading Bacterium Isolated from JP-7-Polluted Soil

    PubMed Central

    Brown, Lisa M.; Gunasekera, Thusitha S.

    2017-01-01

    ABSTRACT Nocardioides luteus strain BAFB is a Gram-positive bacterium that efficiently degrades C8 to C11 alkanes aerobically. The draft genome of N. luteus BAFB is 5.76 Mb in size, with 5,358 coding sequences and 69.9% G+C content. The genes responsible for alkane degradation are present in this strain. PMID:28126947

  11. Metagenomics for the discovery of pollutant degrading enzymes.

    PubMed

    Ufarté, Lisa; Laville, Élisabeth; Duquesne, Sophie; Potocki-Veronese, Gabrielle

    2015-12-01

    Organic pollutants, including xenobiotics, are often persistent and toxic organic compounds resulting from human activities and released in large amounts into terrestrial, fluvial and marine environments. However, some microbial species which are naturally exposed to these compounds in their own habitat are capable of degrading a large range of pollutants, especially poly-aromatic, halogenated and polyester molecules. These microbes constitute a huge reservoir of enzymes for the diagnosis of pollution and for bioremediation. Most are found in highly complex ecosystems like soils, activated sludge, compost or polluted water, and more than 99% have never been cultured. Meta-omic approaches are thus well suited to retrieve biocatalysts from these environmental samples. In this review, we report the latest advances in functional metagenomics aimed at the discovery of enzymes capable of acting on different kinds of polluting molecules. Copyright © 2015. Published by Elsevier Inc.

  12. Soil physical land degradation processes

    NASA Astrophysics Data System (ADS)

    Horn, Rainer

    2017-04-01

    According to the European Soil Framework Directive (2006) soil compaction is besides water and wind erosion one of the main physical reasons and threats of soil degradation. It is estimated, that 32% of the subsoils in Europe are highly degraded and 18% moderately vulnerable to compaction. The problem is not limited to crop land or forest areas (especially because of non-site adjusted harvesting machines) but is also prevalent in rangelands and grassland, and even in so called natural non-disturbed systems. The main reasons for an intense increase in compacted agricultural or forested regions are the still increasing masses of the machines as well the increased frequency of wheeling under non favorable site conditions. Shear and vibration induced soil deformation enhances the deterioration of soil properties especially if the soil water content is very high and the internal soil strength very low. The same is true for animal trampling in combination with overgrazing of moist to wet pastures which subsequently causes a denser (i.e. reduced proportion of coarse pores with smaller continuity) but still structured soil horizons and will finally end in a compacted platy structure. In combination with high water content and shearing due to trampling therefore results in a complete muddy homogeneous soil with no structure at all. (Krümmelbein et al. 2013) Site managements of arable, forestry or horticulture soils requires a sufficiently rigid pore system which guarantees water, gas and heat exchange, nutrient transport and adsorption as well as an optimal rootability in order to avoid subsoil compaction. Such pore system also guarantees a sufficient microbial activity and composition in order to also decompose the plant etc. debris. It is therefore essential that well structured horizons dominate in soils with at best subangular blocky structure or in the top A- horizons a crumbly structure due to biological activity. In contrast defines the formation of a platy

  13. Soil Degradation: A North American perspective

    USDA-ARS?s Scientific Manuscript database

    Soil can be degraded through erosion and formation of undesirable physical, chemical, or biological properties due to industrialization or use of inappropriate farming practices that supersede natural regeneration. Soil degradation reflects unsustainable resource management that is global in scope a...

  14. Photocatalytic Degradation of a Gaseous Organic Pollutant

    NASA Astrophysics Data System (ADS)

    Yu, Jimmy C.; Chan, Linda Y. L.

    1998-06-01

    A simple and effective method to demonstrate the phenomenon of photocatalytic degradation of a gaseous organic pollutant was developed. Titanium dioxide (anatase) was used as the photocatalyst, and sunlight was found to be an effective light source for the activation of TiO2. The organic pollutant degrade in this demonstration was a common indoor air pollutant, dichloromethane. The TiO2 powder was suspended in a 3:7 ethanol/water solution, and then coated on microscopic slides. The slides together with appropriate indicators were place in 250-mL conical flasks. A small amount of the volatile dichloromethane solvent was injected into each flask, and the flasks were sealed with a piece of parafilm. Some of the flasks were exposed to direct sunlight, and some were kept in the dark. The degradation products of dichloromethane were carbon dioxide, water, and hydrogen chloride. Formation of the acidic HCl gas could be monitored easily by two indicators, the universal pH paper and ammonia. The universal pH paper would change color from green to red in the presence of HCl and H2O, while HCl would react with ammonia to form a white fume. The results of this demonstration showed that both TiO2 and light were required in this photocatalytic degradation process.

  15. Degradation of PAHs in soil by indigenous and inoculated bacteria

    SciTech Connect

    Aamand, J.; Bruntse, G.; Jepsen, M.; Joergensen, C.; Jensen, B.K.

    1995-12-31

    In soil heavily polluted by coal tar, the inherent mineralization of radio-labeled phenanthrene to {sup 14}CO{sub 2} was relatively slow, and a stimulation of degradation was observed by inoculation with a mixed population of PAH-degrading bacteria. A much faster inherent mineralization of phenanthrene was observed in soil slightly polluted by coal tar, and inoculation of this soil had no effect. Several phenanthrene-degrading bacteria were isolated from different soils. Two strains were further characterized as an Arthrobacter sp. and a Pseudomonas sp. In an organic medium without phenanthrene, growth rates of 0.52 h{sup {minus}1} and 0.71 h{sup {minus}1} were measured for the Arthrobacter sp. and the Pseudomonas sp., respectively. Most isolates grown in the phenanthrene-free medium, including the Arthrobacter sp., rapidly adapted to phenanthrene degradation following transfer to a phenanthrene-containing medium. In contrast, the phenanthrene-degrading capability of other strains, including the Pseudomonas sp., was lost during growth in the phenanthrene-free medium. Growth in an organic medium without phenanthrene of strains that retain the ability to degrade phenanthrene could prove to be a useful technique for production of PAH-degrading bacteria on a larger scale for soil inoculation.

  16. Monitoring of Gasoline-ethanol Degradation In Undisturbed Soil

    NASA Astrophysics Data System (ADS)

    Österreicher-Cunha, P.; Nunes, C. M. F.; Vargas, E. A.; Guimarães, J. R. D.; Costa, A.

    Environmental contamination problems are greatly emphasised nowadays because of the direct threat they represent for human health. Traditional remediation methods fre- quently present low efficiency and high costs; therefore, biological treatment is being considered as an accessible and efficient alternative for soil and water remediation. Bioventing, commonly used to remediate petroleum hydrocarbon spills, stimulates the degradation capacity of indigenous microorganisms by providing better subsur- face oxygenation. In Brazil, gasoline and ethanol are mixed (78:22 v/v); some authors indicate that despite gasoline high degradability, its degradation in subsurface is hin- dered by the presence of much more rapidly degrading ethanol. Contaminant distribu- tion and degradation in the subsurface can be monitored by several physical, chemical and microbiological methodologies. This study aims to evaluate and follow the degra- dation of a gasoline-ethanol mixture in a residual undisturbed tropical soil from Rio de Janeiro. Bioventing was used to enhance microbial degradation. Shifts in bacte- rial culturable populations due to contamination and treatment effects were followed by conventional microbiology methods. Ground Penetrating Radar (GPR) measure- ments, which consist of the emission of electro-magnetic waves into the soil, yield a visualisation of contaminant degradation because of changes in soil conductivity due to microbial action on the pollutants. Chemical analyses will measure contaminant residue in soil. Our results disclosed contamination impact as well as bioventing stim- ulation on soil culturable heterotrophic bacterial populations. This multidisciplinary approach allows for a wider evaluation of processes occurring in soil.

  17. Degradation of toxaphene in aged and freshly contaminated soil.

    PubMed

    Lacayo-Romero, Martha; van Bavel, Bert; Mattiasson, Bo

    2006-04-01

    Degradation of toxaphene in soil from both newly contaminated (from Sweden) and aged spills (from Nicaragua) were studied. The newly contaminated soil contained approximately 11 mg kg(-1) toxaphene while the aged Nicaraguan soil contained approximately 100 mg kg(-1). Degradation was studied in anaerobic bioreactors, some of which were supplied with lactic acid and others with Triton X-114. In this study we found that the lower isomers Parlar 11, 12 were degraded while the concentration of isomer Parlar 15 increased. This supported an earlier evaluation which indicated that less chlorinated isomers are formed from more heavily isomers. Lactic acid when added to the soil, interfere with the degradation of toxaphene. Lactic acid was added; several isomers appeared to degrade rather slowly in newly contaminated Swedish soil. The Swedish soil, without any external carbon source, showed the slowest degradation rate of all the compounds studied. When Triton X-114 at 0.4 mM was added, the degradation rate of the compounds increased. This study illustrates that biodegradation of toxaphene is a complex process and several parameters have to be taken into consideration. Degradation of persistent pollutants in the environment using biotechnology is dependent on bioavailability, carbon sources and formation of metabolites.

  18. Bioremediation via in situ microbial degradation of organic pollutants.

    PubMed

    Vogt, Carsten; Richnow, Hans Hermann

    2014-01-01

    Contamination of soil and natural waters by organic pollutants is a global problem. The major organic pollutants of point sources are mineral oil, fuel components, and chlorinated hydrocarbons. Research from the last two decades discovered that most of these compounds are biodegradable under anoxic conditions. This has led to the rise of bioremediation strategies based on the in situ biodegradation of pollutants. Monitored natural attenuation is a concept by which a contaminated site is remediated by natural biodegradation; to evaluate such processes, a combination of chemical and microbiological methods are usually used. Compound specific stable isotope analysis emerged as a key method for detecting and quantifying in situ biodegradation. Natural attenuation processes can be initiated or accelerated by manipulating the environmental conditions to become favorable for indigenous pollutant degrading microbial communities or by adding externally breeded specific pollutant degrading microorganisms; these techniques are referred to as enhanced natural attenuation. Xenobiotic micropollutants, such as pesticides or pharmaceuticals, contaminate diffusively large areas in low concentrations; the biodegradation pattern of such contaminations are not yet understood.

  19. Petroleum pollutant degradation by surface water microorganisms.

    PubMed

    Antić, Malisa P; Jovancićević, Branimir S; Ilić, Mila; Vrvić, Miroslav M; Schwarzbauer, Jan

    2006-09-01

    It is well known that the composition of petroleum or some of its processing products changes in the environment mostly under the influence of microorganisms. A series of experiments was conducted in order to define the optimum conditions for an efficient biodegradation of petroleum pollutant, or bioremediation of different segments of the environment. The aim of these investigations was to show to what extent the hydrocarbons of a petroleum pollutant are degraded by microbial cultures which were isolated as dominant microorganisms from a surface water of a wastewater canal of an oil refinery and a nitrogen plant. Biodegradation experiments were conducted on one paraffinic, and one naphthenic type of petroleum during a three month period under aerobic conditions, varying the following parameters: Inorganic (Kp) or an organic medium (Bh) with or without exposition to light. Microorganisms were analyzed in a surface water sample from a canal (Pancevo, Serbia), into which wastewater from an oil refinery and a nitrogen plant is released. The consortia of microorganisms were isolated from the water sample (most abundant species: Phormidium foveolarum--filamentous Cyanobacteria, blue-green algae and Achanthes minutissima, diatoms, algae). The simulation experiments of biodegradation were conducted with the biomass suspension and crude oils Sirakovo (Sir, paraffinic type) and Velebit (Ve, naphthenic type). After a three month period, organic substance was extracted by means of chloroform. In the extracts, the content of saturated hydrocarbons, aromatic hydrocarbons, alcohols and fatty acids was determined (the group composition). n-Alkanes and isoprenoid aliphatic alkanes, pristane and phytane, in the aliphatic fractions, were analyzed using gas chromatography (GC). Total isoprenoid aliphatic alkanes and polycyclic alkanes of sterane and triterpane types were analyzed by GC-MS. Paraffinic type petroleums have a significant loss of saturated hydrocarbons. For naphthenic

  20. Soil organic matter as sole indicator of soil degradation

    Treesearch

    S.E. Obalum; G.U. Chibuike; S. Peth; Ying Ouyang

    2017-01-01

    Soil organic matter (SOM) is known to play vital roles in the maintenance and improvement of many soil properties and processes. These roles, which largely influence soil functions, are a pool of specific contributions of different components of SOM. The soil functions, in turn, normally define the level of soil degradation, viewed as quantifiable temporal changes in a...

  1. Soil degradation effect on biological activity in Mediterranean calcareous soils

    NASA Astrophysics Data System (ADS)

    Roca-Pérez, L.; Alcover-Sáez, S.; Mormeneo, S.; Boluda, R.

    2009-04-01

    Soil degradation processes include erosion, organic matter decline, compaction, salinization, landslides, contamination, sealing and biodiversity decline. In the Mediterranean region the climatological and lithological conditions, together with relief on the landscape and anthropological activity are responsible for increasing desertification process. It is therefore considered to be extreme importance to be able to measure soil degradation quantitatively. We studied soil characteristics, microbiological and biochemical parameters in different calcareous soil sequences from Valencia Community (Easter Spain), in an attempt to assess the suitability of the parameters measured to reflect the state of soil degradation and the possibility of using the parameters to assess microbiological decline and soil quality. For this purpose, forest, scrubland and agricultural soil in three soil sequences were sampled in different areas. Several sensors of the soil biochemistry and microbiology related with total organic carbon, microbial biomass carbon, soil respiration, microorganism number and enzyme activities were determined. The results show that, except microorganism number, these parameters are good indicators of a soil biological activity and soil quality. The best enzymatic activities to use like indicators were phosphatases, esterases, amino-peptidases. Thus, the enzymes test can be used as indicators of soil degradation when this degradation is related with organic matter losses. There was a statistically significant difference in cumulative O2 uptake and extracellular enzymes among the soils with different degree of degradation. We would like to thank Spanish government-MICINN for funding and support (MICINN, project CGL2006-09776).

  2. Degradation of drained peat soils in Belarus

    NASA Astrophysics Data System (ADS)

    Bambalov, N. N.

    2009-04-01

    According to Belarusian classification, the drained peat soils with peat layer less then 30 cm and containing organic substance less then 50% are degraded soils. Degraded peat soils made up 190.2 thousand hectares in 2001 from a total area of 1062,2 thousand hectares of drained peat soils for agriculture in Belarus, but the process of degradation is prolonging now and it is expected, that their area will be extended additionally on 12 % till 2020. The degradation of peat soils is most widespread in the region of Polesie, where the area of degraded soils makes up already several thousand hectares in some administrative districts. The degradation of peat soils takes place jet locally on the comparatively not big plots but on the very many places. There is the threat of joining up of the existing now spots of degraded soils in the near future, and the new spots of degraded soils will appear in a very big amount as well. The large tracts of land will appear in the nearest 20-30 years and may be earlier. The degradation of drained peat soils proceeds step by step, and three morphological groups of new soils are forming depending on degree of humification of organic matter, namely: raw humic, humus-fibrous and humus peat soils. The complicated soil complexes with many alternating soil plots containing organic substance both more than 50 % and from 2 till 50 % are forming within one field in result of degradation. For the reason given above a rather not uniform structure of soil cover with unsatisfactory micro relief, big differences of aquatic, thermal and nutritious regimes is forming on agricultural fields, that leads to the substantial decrease of their productivity. In this connection big expanses will require to the rearrangement of drainage systems and leveling of soil fertility within every such field. A fertility of drained peat soils with the depth of peat layer more then 1 m has been estimated as 69 points, with the depth of peat layer 0.3-0.5 m as 62 points

  3. Soil organic matter as sole indicator of soil degradation.

    PubMed

    Obalum, S E; Chibuike, G U; Peth, S; Ouyang, Y

    2017-04-01

    Soil organic matter (SOM) is known to play vital roles in the maintenance and improvement of many soil properties and processes. These roles, which largely influence soil functions, are a pool of specific contributions of different components of SOM. The soil functions, in turn, normally define the level of soil degradation, viewed as quantifiable temporal changes in a soil that impairs its quality. This paper aims at providing a generalized assessment of the current state of knowledge on the usefulness of SOM in monitoring soil degradation, based on its influence on the physical, chemical and biological properties and processes of soils. Emphasis is placed particularly on the effect of SOM on soil structure and availability of plant nutrients. Although these properties are discussed separately, the soil system is of dynamic and interactive nature, and changes in one property will likely affect other soil properties as well. Thus, functions of SOM almost always affect various soil properties and processes and engage in multiple reactions. In view of its role in soil aggregation and erosion control, in availability of plant nutrients and in ameliorating other forms of soil degradation than erosion, SOM has proven to be an important indicator of soil degradation. It has been suggested, however, that rather than the absolute amount, temporal change and potential amount of SOM be considered in its use as indicator of soil degradation, and that SOM may not be an all-purpose indicator. Whilst SOM remains a candidate without substitute as long as a one-parameter indicator of soil degradation is needed, narrowing down to the use of its labile and microbial components could be more appropriate, since early detection is important in the control and management of soil degradation.

  4. Intrinsic capacities of soil microflorae for gasoline degradation.

    PubMed

    Solano-Serena, F; Marchal, R; Blanchet, D; Vandecasteele, J P

    1998-01-01

    A methodology to determine the intrinsic capacities of a microflora to degrade gasoline was developed, in particular for assessing the potential of autochtonous populations of polluted and non polluted soils for natural attenuation and engineered bioremediation. A model mixture (GM23) constituted of the 23 most representative hydrocarbons of a commercial gasoline was used. The capacities of the microflorae (kinetics and extent of biodegradation) were assessed by chromatographic analysis of hydrocarbon consumption and of CO2 production. The degradation of the components of GM23 was assayed in separate incubations of each component and in the complete mixture. For the microflora of an unpolluted spruce forest soil, all hydrocarbons of GM23 except cyclohexane, 2,2,4- and 2,3,4-trimethylpentane isomers were degraded to below detection limit in 28 days. This microflora was reinforced with two mixed microbial communities selected from gasoline-polluted sites and shown to degrade cyclohexane and 2,2,4-trimethylpentane. With the reinforced microflora, complete degradation of GM23 was observed. The degradation patterns of individual components of GM23 were similar when the compounds were present individually or in the GM23 mixture, as long as the concentrations of 2-ethyltoluene and trimethylbenzene isomers were kept sufficiently low (< or = 35 mg.l-1) to remain below their inhibitory level.

  5. Biocarrier composition for and method of degrading pollutants

    DOEpatents

    Fliermans, C.B.

    1994-01-01

    The present invention relates to biocarrier compositions that attract and bond pollutant-degrading antigens that will degrade the pollutants. Biocarriers are known generally as a variety of inert or semi-inert compounds or structures having the ability to sequester (attract), hold and biomagnify (enhance) specific microorganisms within their structure. Glass or polystyrene beads are the most well known biocarriers. The biocarrier, which is preferably in the form of glass microspheres, is coated with an antibody or group of antibodies that attract and react specifically with certain pollutant-degrading antigens. The antibody, once bonded to the biocarrier, is used by the composition to attract and bond those pollutant-degrading antigens. Each antibody is specific for an antigen that is specific for a given pollutant. The resulting composition is subsequently exposed to an environment contaminated with pollutants for degradation. In the preferred use, the degrading composition is formed and then injected directly into or near a plume or source of contamination.

  6. Considering the Specific Impact of Harsh Conditions and Oil Weathering on Diversity, Adaptation, and Activity of Hydrocarbon-Degrading Bacteria in Strategies of Bioremediation of Harsh Oily-Polluted Soils

    PubMed Central

    Al Disi, Zulfa; Jaoua, Samir; Al-Thani, Dhabia; Al-Meer, Saeed

    2017-01-01

    Weathering processes change properties and composition of spilled oil, representing the main reason of failure of bioaugmentation strategies. Our purpose was to investigate the metabolic adaptation of hydrocarbon-degrading bacteria at harsh conditions to be considered to overcome the limitations of bioaugmentation strategies at harsh conditions. Polluted soils, exposed for prolonged periods to weathered oil in harsh soils and weather conditions, were used. Two types of enrichment cultures were employed using 5% and 10% oil or diesel as sole carbon sources with varying the mineral nitrogen sources and C/N ratios. The most effective isolates were obtained based on growth, tolerance to toxicity, and removal efficiency of diesel hydrocarbons. Activities of the newly isolated bacteria, in relation to the microenvironment from where they were isoalted and their interaction with the weathered oil, showed individual specific ability to adapt when exposed to such factors, to acquire metabolic potentialities. Among 39 isolates, ten identified ones by 16S rDNA genes similarities, including special two Pseudomonas isolates and one Citrobacter isolate, showed particularity of shifting hydrocarbon-degrading ability from short chain n-alkanes (n-C12–n-C16) to longer chain n-alkanes (n-C21–n-C25) and vice versa by alternating nitrogen source compositions and C/N ratios. This is shown for the first time. PMID:28243605

  7. Biocide Runoff from Building Facades: Degradation Kinetics in Soil.

    PubMed

    Bollmann, Ulla E; Fernández-Calviño, David; Brandt, Kristian K; Storgaard, Morten S; Sanderson, Hans; Bester, Kai

    2017-04-04

    Biocides are common additives in building materials. In-can and film preservatives in polymer-resin render and paint, as well as wood preservatives are used to protect facade materials from microbial spoilage. Biocides leach from the facade material with driving rain, leading to highly polluted runoff water (up to several mg L(-1) biocides) being infiltrated into the soil surrounding houses. In the present study the degradation rates in soil of 11 biocides used for the protection of building materials were determined in laboratory microcosms. The results show that some biocides are degraded rapidly in soil (e.g., isothiazolinones: T1/2 < 10 days) while others displayed higher persistence (e.g., terbutryn, triazoles: T1/2 ≫ 120 days). In addition, mass balances of terbutryn and octylisothiazolinone were determined, including nine (terbutryn) and seven (octylisothiazolinone) degradation products, respectively. The terbutryn mass balance could be closed over the entire study period of 120 days and showed that relative persistent metabolites were formed, while the mass balances for octylisothiazolinone could not be closed. Octylisothiazolinone degradation products did not accumulate over time suggesting that the missing fraction was mineralized. Microtox-tests revealed that degradation products were less toxic toward the bacterium Aliivibrio fischeri than their parent compounds. Rain is mobilizing these biocides from the facades and transports them to the surrounding soils; thus, rainfall events control how often new input to the soil occurs. Time intervals between rainfall events in Northern Europe are shorter than degradation half-lives even for many rapidly degraded biocides. Consequently, residues of some biocides are likely to be continuously present due to repeated input and most biocides can be considered as "pseudo-persistent"-contaminants in this context. This was verified by (sub)urban soil screening, where concentrations of up to 0.1 μg g(-1) were

  8. Microbial degradation of sulfentrazone in a Brazilian rhodic hapludox soil

    PubMed Central

    Martinez, Camila O.; Silva, Celia Maria M. S.; Fay, Elisabeth F.; Abakerli, Rosangela B.; Maia, Aline H. N.; Durrant, Lucia R.

    2010-01-01

    Sulfentrazone is amongst the most widely used herbicides for treating the main crops in the State of São Paulo, Brazil, but few studies are available on the biotransformation of this compound in Brazilian soils. Soil samples of Rhodic Hapludox soil were supplemented with sulfentrazone (0.7 µg active ingredient (a.i.) g-1 soil) and maintained at 27°C. The soil moisture content was corrected to 30, 70 or 100 % water holding capacity (WHC) and maintained constant until the end of the experimental period. Herbicide-free soil samples were used as controls. Another experiment was carried out using soil samples maintained at a constant moisture content of 70% WHC, supplemented or otherwise with the herbicide, and submitted to different temperatures of 15, 30 and 40° C. In both experiments, aliquots were removed after various incubation periods for the quantitative analysis of sulfentrazone residues by gas chromatography. Herbicide-degrading microorganisms were isolated and identified. After 120 days a significant effect on herbicide degradation was observed for the factor of temperature, degradation being higher at 30 and 40° C. A half-life of 91.6 days was estimated at 27° C and 70 % WHC. The soil moisture content did not significantly affect sulfentrazone degradation and the microorganisms identified as potential sulfentrazone degraders were Nocardia brasiliensis and Penicillium sp. The present study enhanced the prospects for future studies on the bio-prospecting for microbial populations related to the degradation of sulfentrazone, and may also contribute to the development of strategies for the bioremediation of sulfentrazone-polluted soils. PMID:24031483

  9. Degradation of diesel-originated pollutants in wetlands by Scirpus triqueter and microorganisms.

    PubMed

    Liu, Xiaoyan; Wang, Zhenzhen; Zhang, Xinying; Wang, Jun; Xu, Gang; Cao, Zhengnan; Zhong, Chenglin; Su, Pengcheng

    2011-10-01

    The wetland ecological environment near Huangpu-Yangtze River Estuary (HYRE) is deteriorating more and more seriously due to oil spills. In this paper, the simulation experiment of degradation was conducted to restore the diesel pollution in soils where the decontaminating potential of indigenous hydrocarbon-degrading microorganisms (HDMs) was evaluated with pot experiments and the co-activation between HDMs and native plant, Scirpus triqueter L.(STL), was investigated. The experimental results indicated that HDMs isolated from HYRE wetland had a degradation effect on diesel pollutants. Within 60 days, the removal ratio of diesel compared with initial amount could be up to 57.27 ± 8.18% in the HDMs inoculated soils at different concentrations of diesel. It was also found that the growth of Scirpus triqueter could enhance the degradation and remediation of diesel pollutants by increasing the populations of microorganisms. A community of STL and HDMs showed a remarkable capability of degrading hydrocarbon components in diesels. Under the combined effects of HDMs and STL (STL-Ms), the removal ratio of diesel pollutants could reach 67.42 ± 8.92%. For example, at 15,000 mg kg(-1) diesel concentration the removal ratios in the HDMs and STL-Ms soils were 67.41% and 72.62%, respectively. Moreover, the saturated hydrocarbons were more readily degraded than the aromatic hydrocarbons in treated soils showing a good degradation effect on the range of C(16)-C(24)n-alkanes, especially C(19). Positive correlations between microbial populations and diesel removal ratios were observed during the experiment. Microbial populations were found significantly higher in the HDMs soils and rhizosphere soils than in the control ones. The results confirmed that the HDMs and plant improved the biodegradation ability for diesel pollutants and they could be reasonably matched to cure and restore the ecological environment of oil-contaminated wetlands.

  10. Environmental degradation of chlorpyrifos in soil

    SciTech Connect

    Cink, J.H.; Coats, J.R.

    1995-12-31

    Dursban TC has become the most widely used insecticide for the control of termites since the banning of chlordane. Several laboratory studies have been conducted to investigate the degradation kinetics of chlorpyrifos applied to soil at termiticide rates. These have included a limited number of soil types and have utilized tightly regulated environmental conditions. A field study was established to investigate the degradation of chlorpyrifos in soil treated with a 1% solution via trench application and under natural environmental conditions. Once treated, soil samples were removed from the trench at scheduled intervals and extracted to determine the concentration chlorpyrifos remaining. In three of the soils studied, the concentration of chlorpyrifos decreased dramatically within the first three months. The remaining soils showed a steady decline in concentration over 12 months. After this initial phase of degradation, the slope of the degradation curve changed sharply. This may indicate that chlorpyrifos undergoes two phases of degradation in soil. Using both phases of the degradation curves may give a better estimate of the concentration of chlorpyrifos that may be present in a soil at any time period.

  11. Reducing Nutrient Losses with Directed Fertilization of Degraded Soils

    NASA Astrophysics Data System (ADS)

    Menzies, E.; Walter, M. T.; Schneider, R.

    2016-12-01

    Degraded soils around the world are stunting agricultural productivity in places where people need it the most. In China, hundreds of years of agriculture and human activity have turned large swaths of productive grasslands into expanses of sandy soils where nothing can grow. Returning soils such as these to healthy productive landscapes is crucial to the livelihoods of rural families and to feeding the expanding population of China and the world at large. Buried wood chips can be used to improve the soils' water holding capacity but additional nutrient inputs are crucial to support plant growth and completely restore degraded soils in China and elsewhere. Improperly applied fertilizer can cause large fluxes of soluble nutrients such as nitrogen (N) and phosphorus (P) to pollute groundwater, and reach surface water bodies causing harmful algal blooms or eutrophication. Similarly, fertilization can create increases in nutrient losses in the form of greenhouse gases (GHGs). It is imperative that nutrient additions to this system be done in a way that fosters restoration and a return to productivity, but minimizes nutrient losses to adjacent surface water bodies and the atmosphere. The primary objective of this study is to characterize soluble and gaseous N and P losses from degraded sandy soils with wood chip and fertilizer amendments in order to identify optimal fertilization methods, frequencies, and quantities for soil restoration. A laboratory soil column study is currently underway to begin examining these questions results of this study will be presented at the Fall Meeting.

  12. Degradation of monomethylhydrazine by two soil bacteria

    SciTech Connect

    Ou, L.T.

    1988-12-01

    It has been reported that three heterotrophic soil bacteria had the capacity to degrade hydrazine. One of these organisms, Achromobacter sp., degraded hydrazine to N/sub 2/ gas. Furthermore, it was reported that monomethylhydrazine (MMH) in Arredondo fine sand was mineralized to CO/sub 2/, and that such degradation is microbial. However, microorganisms that degrade MMH have not been reported. MMH and hydrazine are chemically similar to one another. Therefore, this study was initiated to test the capacity of the two hydrazine-degrading bacteria, Achromobacter sp. and Pseudomonas sp., to degrade MMH.

  13. Identification of soil bacteria able to degrade phenanthrene bound to a hydrophobic sorbent in situ.

    PubMed

    Regonne, Raïssa Kom; Martin, Florence; Mbawala, Augustin; Ngassoum, Martin Benoît; Jouanneau, Yves

    2013-09-01

    Efficient bioremediation of PAH-contaminated sites is limited by the hydrophobic character and poor bioavailability of pollutants. In this study, stable isotope probing (SIP) was implemented to track bacteria that can degrade PAHs adsorbed on hydrophobic sorbents. Temperate and tropical soils were incubated with (13)C-labeled phenanthrene, supplied by spiking or coated onto membranes. Phenanthrene mineralization was faster in microcosms with PAH-coated membranes than in microcosms containing spiked soil. Upon incubation with temperate soil, phenanthrene degraders found in the biofilms that formed on coated membranes were mainly identified as Sphingomonadaceae and Actinobacteria. In the tropical soil, uncultured Rhodocyclaceae dominated degraders bound to membranes. Accordingly, ring-hydroxylating dioxygenase sequences recovered from this soil matched PAH-specific dioxygenase genes recently found in Rhodocyclaceae. Hence, our SIP approach allowed the detection of novel degraders, mostly uncultured, which differ from those detected after soil spiking, but might play a key role in the bioremediation of PAH-polluted soils.

  14. Photochemically enhanced microbial degradation of environmental pollutants

    SciTech Connect

    Katayama, Arata; Matsumura, Fumio )

    1991-07-01

    Biodegradation of persistent halogenated organic pollutants is of great interest from the viewpoint of its potential use to cleanup the contaminated sites and industrial waste streams on-site (i.e., in situ remediation). Recent studies have shown that lignin-degrading white rot fungi possess capabilities to degrade a variety of highly recalcitrant and toxic compounds. On the other hand, photodegradation by sunlight or ultraviolet light (UV) has not been considered as a potential technology to detoxify the contaminated sites, in spite of the availability of extensive research data, because of its limited reaching ability to subsurface locations. In view of the urgent needs for the development of technology to deal with mounting problems of toxic wastes, the authors have decided to experiment with the ideas of combining photochemical and microbial technologies. The main obstacle in developing such simultaneous combination systems has been the susceptibilities of microorganisms in general to UV irradiation. To overcome this problem, the authors have developed an ultraviolet- and fungicide-resistant strain of white rot fungus and now report their results.

  15. Degradation of ¹³C-labeled pyrene in soil-compost mixtures and fertilized soil.

    PubMed

    Adam, Iris K U; Miltner, Anja; Kästner, Matthias

    2015-11-01

    Polycyclic aromatic hydrocarbons (PAH) are toxic pollutants widely distributed in the environment due to natural and anthropogenic processes. In order to mitigate tar oil contaminations with PAH, research on improving bioremediation approaches, which are sometimes inefficient, is needed. However, the knowledge on the fate of PAH-derived carbon and the microbial degraders in particular in compost-supplemented soils is still limited. Here we show the PAH carbon turnover mass balance in microcosms with soil-compost mixtures or in farmyard fertilized soil using [(13)C6]-pyrene as a model PAH. Complete pyrene degradation of 100 mg/kg of soil was observed in all supplemented microcosms within 3 to 5 months, and the residual (13)C was mainly found as carbon converted to microbial biomass. Long-term fertilization of soil with farmyard manure resulted in pyrene removal efficiency similar to compost addition, although with a much longer lag phase, higher mineralization, and lower carbon incorporation into the biomass. Organic amendments either as long-term manure fertilization or as compost amendment thus play a key role in increasing the PAH-degrading potential of the soil microbial community. Phospholipid fatty acid stable isotope probing (PLFA-SIP) was used to trace the carbon within the microbial population and the amount of biomass formed from pyrene degradation. The results demonstrate that complex microbial degrader consortia rather than the expected single key players are responsible for PAH degradation in organic-amended soil.

  16. Ex situ remediation of polluted soils by absorptive polymers, and a comparison of slurry and two-phase partitioning bioreactors for ultimate contaminant degradation.

    PubMed

    Tomei, M Concetta; Mosca Angelucci, Domenica; Annesini, M Cristina; Daugulis, Andrew J

    2013-11-15

    The present study has provided a comparison between a conventional ex situ method for the treatment of contaminated soil, a soil slurry bioreactor, with a novel technology in which a contaminant is rapidly and effectively removed from the soil by means of absorptive polymer beads, which are then added to a two-phase partitioning bioreactor (TPPB) for biodegradation of the target molecule. 4-nitrophenol (4NP) was selected as a model contaminant, being representative of a large class of xenobiotics, and the DuPont thermoplastic Hytrel™ 8206 was utilized for its extraction from soil over ranges of soil contamination level, soil moisture content, and polymer:soil ratios. Since the polymers were able to rapidly (up to 77% and 85% in 4 and 24h respectively) and selectively remove the contaminant, the soil retained its nutrient and microflora content, which is in contrast to soil washing which can remove these valuable soil resources. After 4h of reaction time, the TPPB system demonstrated removal efficiency four times higher (77% vs 20%) than the slurry system, with expected concomitant savings in time and energy. A volumetric removal rate of 75 mg4NPh(-1) L(-1) was obtained in the TPPB, significantly greater than the value of 1.7 obtained in the slurry bioreactor. The polymers were readily regenerated for subsequent reuse, demonstrating the versatility of the polymer-based soil treatment technology.

  17. Pollution of soils in urban areas in Serbia

    NASA Astrophysics Data System (ADS)

    Grujic, Gordana; Crnkovic, Dragan; Cerdà, Artemi

    2017-04-01

    , Cr, Hg and organic pollutants. A special surveillance of soil pollution is related to the determination of the contents of hazardous and harmful substances in the soil surrounding public fountains with drinking water. The results indicated an increased content of Pb, Cd, Zn, Cu and pesticide residues that could lead to deterioration of the quality of drinking water of these springs and to endanger the health of the population that use this water. Investigation included determination of the level of radioactive elements in soil such are Cs, Sr and U. The presence of the registered harmful and hazardous substances in the soil on the territory of Belgrade requires continued monitoring the content of these pollutants including an assessment of potential adverse effects on the human health and the environment, as well as undertaking the necessary prevention and protection measures. Acknowledgements. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 603498 (RECARE project) References Adamcová, D., Vaverková, M.D., Bartoň, S., Havlíček, Z., Břou\\vsková, E. 2016. Soil contamination in landfills: A case study of a landfill in Czech Republic. Solid Earth, 7 (1), pp. 239-247. DOI: http://dx.doi.org/10.5194/se-7-239-2016 Brevik, E. C., Cerdà, A., Mataix-Solera, J., Pereg, L., Quinton, J. N., Six, J., and Van Oost, K. 2015. The interdisciplinary nature of SOIL, SOIL, 1, 117-129, doi:10.5194/soil-1-117-2015, Elkhatib, E., M. Moharem, A. Mahdy, and M. Mesalem. 2016. Sorption, Release and Forms of Mercury in Contaminated Soils Stabilized with Water Treatment Residual Nanoparticles. Land Degradation and Development. doi:10.1002/ldr.2559. Hu, Y. -L, Z. -X Niu, D. -H Zeng, and C. -Y Wang. 2015. Soil Amendment Improves Tree Growth and Soil Carbon and Nitrogen Pools in Mongolian Pine Plantations on Post-Mining Land in Northeast China. Land Degradation and Development 26 (8

  18. Modification to degradation of hexazinone in forest soils amended with sewage sludge.

    PubMed

    Wang, Huili; Wang, Chengjun; Chen, Fan; Ma, Meiping; Lin, Zhenkun; Wang, Wenwei; Xu, Zhengti; Wang, Xuedong

    2012-01-15

    Influences of one sewage sludge on degradation of hexazinone and formation of its major metabolites were investigated in four forest soils (A, B, C and D), collected in Zhejiang Province, China. In non-amended forest soils, the degradation half-life of hexazinone was 21.4, 30.4, 19.4 and 32.8 days in forest soil A, B, C and D, respectively. Degradation could start in soil A and C without lag period because the two soils had been contaminated by this herbicide for a long time, possibly leading to completion of acclimation period of hexazinone-degrading bacteria. In forest soils amended with sewage sludge, the degradation rate constant increased by 17.3% in soil A, 48.2% in soil B, 8.1% in soil C and 51.6% in soil D, respectively. The higher degradation rates (soil A and C) in non-amended soils accord with the lower rate increase in sewage sludge-amended soils. Under non-sterile conditions, biological mechanism accounted for 51.8-62.4% of hexazinone degradation in four soils. Under sterile conditions, the four soils had the similar chemical degradation capacity for hexazinone. In non-amended soil B, only one metabolite (B) was detected, while two metabolites (B and C) were found in sewage sludge-amended soil B. Similarly situated in agricultural soils, N-demethylation at 6-position of triazine ring, hydroxylation at the 4-positon of cyclohexyl group, and removal of the dimethylamino group with formation of a carbonyl group at 6-position of triazine ring appear to be the principal mechanism involved in hexazinone degradation in sewage sludge-amended forest soils. These data will improve understanding of the actual pollution risk as a result of forest soil fertilization with sewage sludge.

  19. Enantioselective degradation of warfarin in soils.

    PubMed

    Lao, Wenjian; Gan, Jay

    2012-01-01

    Environmental enantioselectivity information is important to fate assessment of chiral contaminants. Warfarin, a rodenticide and prescription medicine, is a chiral chemical but used in racemic form. Little is known about its enantioselective behavior in the environment. In this study, enantioselective degradation of warfarin in a turfgrass and a groundcover soils was examined in aerobic and ambient temperature conditions. An enantioselective analytical method was established using a novel triproline chiral stationary phase in high performance liquid chromatography. Unusual peak profile patterns, i.e., first peak (S(-)) broadening/second peak (R(+)) compression with hexane (0.1%TFA)/2-propanol (92/8, v/v) mobile phase, and first peak compression/second peak broadening with the (96/4, v/v) mobile phase, were observed in enantioseparation. This unique tunable peak property was leveraged in evaluating warfarin enantioselective degradation in two types of soil. Warfarin was extracted in high recovery from soil using methylene chloride after an aqueous phase basic-acidic conversion. No apparent degradation of warfarin was observed in the sterile turfgrass and groundcover soils during the 28 days incubation, while it showed quick degradation (half-life <7 days) in the nonsterile soils after a short lag period, suggesting warfarin degradation in the soils was mainly caused by micro-organisms. Limited enantioselectivity was found in the both soils, which was the R(+) enantiomer was preferentially degraded. The half-lives in turfgrass soil were 5.06 ± 0.13 and 5.97 ± 0.05 days, for the R(+) and the S(-) enantiomer, respectively. The corresponding values for the groundcover soil were 4.15 ± 0.11 and 4.47 ± 0.08 days. Copyright © 2011 Wiley-Liss, Inc.

  20. Rehabilitation of oil polluted soils by bioremediation

    NASA Astrophysics Data System (ADS)

    Dumitru, Mihail; Parvan, Lavinia; Cioroianu, Mihai; Carmen, Sirbu; Constantin, Carolina

    2015-04-01

    In Romania about 50,000 ha are polluted with oil and/or brine. The main sources of pollution are the different activities using petroleum products: extraction, transport, treatment, refining and distribution. Taking into acoount the large areas and the cost per unit area, bioremediation was tested as a method of rehabilitation. To stimulate the performance of the bioremediation process for a polluted soil (luvisol) by 3% oil, different methods were tested: -application of a bacterial inoculum consisting of species of the Pseudomonas and Arthrobacter genera;- application of two types of absorbent materials, 16 t/ha peat and 16, respectively, 32 kg/ha Zeba (starch-based polymer, superabsorbent); -mineral fertilization with N200P200K200 and 5 different liquid fertilizer based on potassium humates extracted from lignite in a NPK matrix with micronutrients and added monosaccharides (4 and 8%). After 45 days from the treatment (60 days from pollution) the following observations have been noticed: • the application of only bacterial inoculum had no significant effect on the degradation of petroleum hydrocarbons; • the use of 650 l/ha AH-SH fertilizer (potassium humate in a NPK matrix) led to a 47% decrease of TPH (total petroleum hydrocarbons); • the application of 16 t/ha peat, together with the bacterial inoculum and the AH-SG2 liquid fertilizer (containing humates of potassium in a NPK matrix with microelements and 8% monosaccharides, in which the nitrogen is amide form) led to a 50% decrease of the TPH content; • the application of 16 kg/ha Zeba absorbent together with bacterial inoculum and 650 l/ha AH-SG1 liquid fertilizer (containing humates of potassium in a NPK matrix with microelements and 4% monosaccharide in which the nitrogen is in amide form) led to a 57% decrease of the TPH content; • the application of 32 kg/ha Zeba absorbent, together with the AH-SG2 fertilizer, led to a 58% decrease of the TPH content.

  1. Degradation of chlorpyrifos in tropical rice soils.

    PubMed

    Das, Subhasis; Adhya, Tapan K

    2015-04-01

    Chlorpyrifos [O,O-diethyl O-(3,5,6-trichloro-2-pyridinol) phosphorothioate] is used worldwide as an agricultural insecticide against a broad spectrum of insect pests of economically important crops including rice, and soil application to control termites. The insecticide mostly undergoes hydrolysis to diethyl thiophosphoric acid (DETP) and 3,5,6-trichloro-2-pyridinol (TCP), and negligible amounts of other intermediate products. In a laboratory-cum-greenhouse study, chlorpyrifos, applied at a rate of 10 mg kg(-1) soil to five tropical rice soils of wide physico-chemical variability, degraded with a half-life ranging from 27.07 to 3.82 days. TCP was the major metabolite under both non-flooded and flooded conditions. Chlorpyrifos degradation had significant negative relationship with electrical conductivity (EC), cation exchange capacity (CEC), clay and sand contents of the soils under non-flooded conditions. Results indicate that degradation of chlorpyrifos was accelerated with increase in its application frequency, across the representative rice soils. Management regimes including moisture content and presence or absence of rice plants also influenced the process. Biotic factors also play an important role in the degradation of chlorpyrifos as demonstrated by its convincing degradation in mineral salts medium inoculated with non-sterile soil suspension.

  2. Soil-ecological risks for soil degradation estimation

    NASA Astrophysics Data System (ADS)

    Trifonova, Tatiana; Shirkin, Leonid; Kust, German; Andreeva, Olga

    2016-04-01

    Soil degradation includes the processes of soil properties and quality worsening, primarily from the point of view of their productivity and decrease of ecosystem services quality. Complete soil cover destruction and/or functioning termination of soil forms of organic life are considered as extreme stages of soil degradation, and for the fragile ecosystems they are normally considered in the network of their desertification, land degradation and droughts /DLDD/ concept. Block-model of ecotoxic effects, generating soil and ecosystem degradation, has been developed as a result of the long-term field and laboratory research of sod-podzol soils, contaminated with waste, containing heavy metals. The model highlights soil degradation mechanisms, caused by direct and indirect impact of ecotoxicants on "phytocenosis- soil" system and their combination, frequently causing synergistic effect. The sequence of occurring changes here can be formalized as a theory of change (succession of interrelated events). Several stages are distinguished here - from heavy metals leaching (releasing) in waste and their migration downward the soil profile to phytoproductivity decrease and certain phytocenosis composition changes. Phytoproductivity decrease leads to the reduction of cellulose content introduced into the soil. The described feedback mechanism acts as a factor of sod-podzolic soil self-purification and stability. It has been shown, that using phytomass productivity index, integrally reflecting the worsening of soil properties complex, it is possible to solve the problems dealing with the dose-reflecting reactions creation and determination of critical levels of load for phytocenosis and corresponding soil-ecological risks. Soil-ecological risk in "phytocenosis- soil" system means probable negative changes and the loss of some ecosystem functions during the transformation process of dead organic substance energy for the new biomass composition. Soil-ecological risks estimation is

  3. Screening model for volatile pollutants in dual porosity soils

    NASA Astrophysics Data System (ADS)

    Hantush, Mohamed M.; Govindaraju, Rao. S.; Mariño, Miguel A.; Zhang, Zhonglong

    2002-03-01

    This paper develops mass fraction models for transport and fate of agricultural pollutants in structured two-region soils. Mass fraction index models, based on a semi-infinite domain solution, are derived that describe leaching at depth, vapor losses through soil surface, absorption, and degradation in the dynamic- and stagnant-water soil regions. The models predict that leaching is the result of the combined effect of the upward vapor-phase transport relative to downward advection, residence time relative to half-life, dispersion, and lateral diffusive mass transfer. Simulations show that leached fraction of volatile compounds does not always decrease monotonically with increased residence time relative to the pollutant half-life, as a result of complex interactions among the different physical and biochemical processes. The results show that leaching, volatilization, and degradation losses can be affected significantly by lateral diffusive mass transfer into immobile-water regions and advection relative to dispersion (i.e. Peclet number) in the mobile-water regions. It is shown that solute diffusion into the immobile phase and subsequent biochemical decay reduces leaching and vapor losses through soil surface. Potential use of the modified leaching index for the screening of selected pesticides is illustrated for different soil textures and infiltration rates. The analysis may be useful to the management of pesticides and the design of landfills.

  4. ELECTROCHEMICAL DEGRADATION OF PERSISTANCE POLLUTANTS IN GROUNDWATER AND SEDIMENTS

    EPA Science Inventory

    Electrochemical Degradation (ECD) utilizes redox potential at the anode and the cathode to oxidize and/or reduce organic contaminants. ECD of environmentally persistence pollutants such chlorinate solvents, PCBs, and PAHs, although theoretically possible, has not been experimenta...

  5. ELECTROCHEMICAL DEGRADATION OF PERSISTANCE POLLUTANTS IN GROUNDWATER AND SEDIMENTS

    EPA Science Inventory

    Electrochemical Degradation (ECD) utilizes redox potential at the anode and the cathode to oxidize and/or reduce organic contaminants. ECD of environmentally persistence pollutants such chlorinate solvents, PCBs, and PAHs, although theoretically possible, has not been experimenta...

  6. Thermal treatment of polluted soil

    SciTech Connect

    Hodges, H.; Wells, S.K.

    1995-02-01

    Thermal treatment for the remediation soils contaminated with petroleum hydrocarbons is described. It is recommended tat a thorough analysis be performed of the situation including well monitoring and contamination testing, records review, and sampling.

  7. [Changed soil properties after pollution by oilfield brine at the Tuimazy oilfield (Republic of Bashkortostan)].

    PubMed

    Suleĭmanov, R R

    2005-01-01

    Changes in the main soil properties under the influence of oilfield brines were studied at the Tuimazy Oilfield. High salinization was observed in the cinnamonic forest soil one year after pollution. Progressing alkalinization deteriorated the main soil properties. The chemical composition of the aqueous extract and the ionic composition of the soil absorption complex changed, the base exchange capacity decreased, the humus state deteriorated, and enzyme activity was suppressed. In the meadow calcareous chernozem polluted 12 years ago, desalinization processes increased alkalinization and thus further degraded the soil.

  8. Soil pollution in the railway junction Niš (Serbia) and possibility of bioremediation of hydrocarbon-contaminated soil

    NASA Astrophysics Data System (ADS)

    Jovanovic, Larisa; Aleksic, Gorica; Radosavljevic, Milan; Onjia, Antonije

    2015-04-01

    Mineral oil leaking from vehicles or released during accidents is an important source of soil and ground water pollution. In the railway junction Niš (Serbia) total 90 soil samples polluted with mineral oil derivatives were investigated. Field work at the railway Niš sites included the opening of soil profiles and soil sampling. The aim of this work is the determination of petroleum hydrocarbons concentration in the soil samples and the investigation of the bioremediation technique for treatment heavily contaminated soil. For determination of petroleum hydrocarbons in the soil samples method of gas-chromatography was carried out. On the basis of measured concentrations of petroleum hydrocarbons in the soil it can be concluded that: Obtained concentrations of petroleum hydrocarbons in 60% of soil samples exceed the permissible values (5000 mg/kg). The heavily contaminated soils, according the Regulation on the program of systematic monitoring of soil quality indicators for assessing the risk of soil degradation and methodology for development of remediation programs, Annex 3 (Official Gazette of RS, No.88 / 2010), must be treated using some of remediation technologies. Between many types of phytoremediation of soil contaminated with mineral oils and their derivatives, the most suitable are phytovolatalisation and phytostimulation. During phytovolatalisation plants (poplar, willow, aspen, sorgum, and rye) absorb organic pollutants through the root, and then transported them to the leaves where the reduced pollutants are released into the atmosphere. In the case of phytostimulation plants (mulberry, apple, rye, Bermuda) secrete from the roots enzymes that stimulates the growth of bacteria in the soil. The increase in microbial activity in soil promotes the degradation of pollutants. Bioremediation is performed by composting the contaminated soil with addition of composting materials (straw, manure, sawdust, and shavings), moisture components, oligotrophs and

  9. Degradation of Nitroguanidine in Soils

    DTIC Science & Technology

    1985-01-01

    addition, air stripping for the ammonia produced could be considered. Final treatment of process waters could be accomplished with land application...CLASSIFICATION OF THIS PAGE (When Data Entered) 4 hese results indicate that land applied process water laden with nitroguanidine can be successfully treated... process , otherwise the nitroguanidine will not degrade and will leach directly into groundwaters. Preliminary work with guanidine nitrate showed this

  10. Effect of toluene as gaseous cosubstrate in bioremediation of hydrocarbon-polluted soil.

    PubMed

    Ortiz, Irmene; Velasco, Antonio; Revah, Sergio

    2006-04-17

    The stimulation of the microbial population by a more bioavailable supplementary carbon source and by a surfactant pretreatment was studied in petroleum hydrocarbon-polluted soils bioremediation. Two types of soils were used, Soil A which had been recently polluted and the aged Soil B. They contained 52.4 and 50.4 g of total petroleum hydrocarbons per kg of dry soil, respectively. The effect of passing a continuous small stream of air containing a low concentration of gaseous toluene through packed 0.5 l (Ø=5.5 cm) columns was studied. For Soil A, after 62 days the THPs degradation was 28% higher in the toluene treated columns than in controls. In aged Soil B the effect of toluene was not significant, probably due to bioavailability limitations. With Soil B, the combined effect of toluene as cosubstrate and a surfactant pretreatment was studied and the hydrocarbons degradation was 29% higher in the toluene-amended columns than in the controls. Toluene removal was higher than 99% in all cases. Surfactant addition increased hydrocarbon degradation when toluene was also added suggesting that the biological reaction was the limiting process. The study shows the possibilities of using gaseous substrates, such as toluene, for the in situ or ex situ treatment of petroleum hydrocarbon-polluted soil in processes limited by the biological reaction. The main advantage of the treatment is that the compound can be easily and directly delivered to the polluted soil through the venting system.

  11. Microbial enhancement of hydrazine degradation in soil and water

    SciTech Connect

    Ou, L.T.; Street, J.J.

    1987-09-01

    In an early study, the authors reported that hydrazine was rapidly degraded in Arredondo fine sand. By comparing the degradation results in sterile and nonsterile soils, it was concluded that biological degradation was responsible for about 20% of hydrazine disappearance from soils. They isolated a heterotrophic bacterium, Achromobacter sp., from the Arredondo soil and found that the organism had a high capacity to degrade hydrazine to the nontoxic product dinitrogen gas. In the present study, the authors attempted to enhance hydrazine degradation in water and soil samples by inoculating with a hydrazine-degrading bacterium, Achromobacter sp. Factors that influence hydrazine degradation in water and soil are discussed.

  12. Augmenting atrazine and hexachlorobenzene degradation under different soil redox conditions in a bioelectrochemistry system and an analysis of the relevant microorganisms.

    PubMed

    Wang, Hui; Cao, Xian; Li, Lei; Fang, Zhou; Li, Xianning

    2017-09-20

    Soil microbial fuel cells (MFCs) are a sustainable technology that degrades organic pollutants while generating electricity. However, there have been no detailed studies of the mechanisms of pollutant degradation in soil MFCs. In this study, the effects of external resistance and electrode effectiveness on atrazine and hexachlorobenzene (HCB) degradation were evaluated, the performance of soil MFCs in the degradation of these pollutants under different soil redox conditions was assessed, and the associated microorganisms in the anode were investigated. With an external resistance of 20Ω, the degradation efficiencies of atrazine and HCB were 95% and 78%, respectively. The degradation efficiency, degradation rate increased with decreasing external resistance, while the half-life decreased. There were different degradation trends for different pollutants under different soil redox conditions. The fastest degradation rate of atrazine was in the upper MFC section (aerobic), whereas that of HCB was in the lower MFC section (anaerobic). The results showed that electrode effectiveness played a significant role in pollution degradation. In addition, the microbial community analysis demonstrated that Proteobacteria, especially Deltaproteobacteria involved in current generation was extremely abundant (27.49%) on soil MFC anodes, although the percentage abundances of atrazine degrading Rhodocyclaceae (8.77%), Desulfitobacterium (0.64%), and HCB degrading Desulfuromonas (0.73%), were considerably lower. The results of the study suggested that soil MFCs can enhance the degradation of atrazine and HCB, and bioelectrochemical reduction was the main mechanism for the pollutants degradation. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Plant species influence on soil C after afforestation of Mediterranean degraded soils

    NASA Astrophysics Data System (ADS)

    Dominguez, Maria T.; García-Vargas, Carlos; Madejón, Engracia; Marañón, Teodoro

    2015-04-01

    Increasing C sequestration in terrestrial ecosystems is one of the main current environmental challenges to mitigate climate change. Afforestation of degraded and contaminated lands is one of the key strategies to achieve an increase in C sequestration in ecosystems. Plant species differ in their mechanisms of C-fixation, C allocation into different plant organs, and interaction with soil microorganisms, all these factors influencing the dynamics of soil C following the afforestation of degraded soils. In this work we examine the influence of different woody plant species on soil C dynamics in degraded and afforested Mediterranean soils. The soils were former agricultural lands that were polluted by a mining accident and later afforested with different native plant species. We analysed the effect of four of these species (Olea europaea var. sylvestris Brot., Populus alba L., Pistacia lentiscus L. and Retama sphaerocarpa (L.) Boiss.) on different soil C fractions, soil nutrient availability, microbial activity (soil enzyme activities) and soil CO2 fluxes 15 years after the establishment of the plantations. Results suggest that the influence of the planted trees and shrubs is still limited, being more pronounced in the more acidic and nutrient-poor soils. Litter accumulation varied among species, with the highest C accumulated in the litter under the deciduous species (Populus alba L.). No differences were observed in the amount of total soil organic C among the studied species, or in the concentrations of phenols and sugars in the dissolved organic C (DOC), which might have indicated differences in the biodegradability of the DOC. Microbial biomass and activity was highly influenced by soil pH, and plant species had a significant influence on soil pH in the more acidic site. Soil CO2 fluxes were more influenced by the plant species than total soil C content. Our results suggest that changes in total soil C stocks after the afforestation of degraded Mediterranean

  14. Soil degradation: Will humankind ever learn?

    USDA-ARS?s Scientific Manuscript database

    Soil degradation is a global problem caused by many factors including excessive tillage, inappropriate crop rotations, excessive grazing or crop residue removal, deforestation, mining, construction and urban sprawl. To meet the needs of an expanding global population, it is essential for humankind t...

  15. Chemical Degradation of PCBs in Alaskan Soils

    DTIC Science & Technology

    2011-04-01

    faster degradation. It is purportedly more effective for the treatment of DNT ( Britto et al. 2010) as well. The higher pH produced by NaOH was used to...Services, Public Health Service. Britto , B., M. Patel, and M. Spangberg. 2010. Full-scale alkaline hydrolysis of TNT and DNT in soil. Presented at The

  16. Modeling organic micro pollutant degradation kinetics during sewage sludge composting.

    PubMed

    Sadef, Yumna; Poulsen, Tjalfe Gorm; Bester, Kai

    2014-11-01

    Degradation of 13 different organic micro-pollutants in sewage sludge during aerobic composting at 5 different temperatures over a 52 day period was investigated. Adequacy of two kinetic models: a single first order, and a dual first order expression (using an early (first 7 days) and a late-time (last 45 days) degradation coefficient), for describing micro-pollutant degradation, and kinetic constant dependency on composting temperature were evaluated. The results showed that both models provide relatively good descriptions of the degradation process, with the dual first order model being most accurate. The single first order degradation coefficient was 0.025 d(-1) on average across all compounds and temperatures. At early times, degradation was about three times faster than at later times. Average values of the early and late time degradation coefficients for the dual first order model were 0.066 d(-1) and 0.022 d(-1), respectively. On average 30% of the initial micro-pollutant mass present in the compost was degraded rapidly during the early stages of the composting process. Single first order and late time dual first order kinetic constants were strongly dependent on composting temperature with maximum values at temperatures of 35-65°C. In contrast the early time degradation coefficients were relatively independent of composting temperature.

  17. Soiling and degradation analysis of solar mirrors

    NASA Astrophysics Data System (ADS)

    Delord, Christine; Blaise, Anthony; Fernandez-García, Aránzazu; Martínez-Arcos, Lucía; Sutter, Florian; Reche-Navarro, Tomás Jesús

    2016-05-01

    The degradation and the soiling of the mirrors are dependent of the solar field and the mirrors technologies, the local climate, the meteorological events, the O&M tasks and the human activities around the site. In the frame of the European project SFERA II, the SODAM project has been the opportunity to compare the soiling and the degradation mechanisms on a Fresnel solar field installed in the South of France and on a parabolic-through solar field installed in the South of Spain. The analysis of the soiling has shown equivalent maximum weekly reflectance loss due to soiling in both sites but a double mean weekly reflectance loss in Spain respect to France, as well as typical meteorological events to be taken into account to adapt the cleaning strategies. Among the meteorological parameters mainly influencing the soiling, the study has revealed the effect of the rain and of the DNI. In parallel, the analysis of the degradation mechanisms has highlighted a common chalking of the protective back paint layers due to the irradiation. This chalking being associated to a leaching of the paint layers in the site of Cadarache due to the high presence of liquid water. A difference in the speed of corrosion of the silver layer has been also noticed, leading to a difference in the mechanisms of delamination of the paints layers.

  18. Effects of biochar on the transformation and earthworm bioaccumulation of organic pollutants in soil.

    PubMed

    Gu, Jianqiang; Zhou, Wenqiang; Jiang, Bingqi; Wang, Lianhong; Ma, Yini; Guo, Hongyan; Schulin, Rainer; Ji, Rong; Evangelou, Michael W H

    2016-02-01

    Little is known about the effects of biochar on the fate and behavior of micropollutants in soil, especially in the presence of soil macrofauna. Using a 14C-tracer, we studied the fate of 2,4-dichlorophenol and phenanthrene, after 30 days in soil in the presence of a biochar (0-5%, dry weight) produced from China fir at 400 °C and/or the earthworm Metaphire guillelmi. Application of the biochar significantly reduced the degradation and mineralization of both pollutants and strongly increased the accumulation of their metabolites in soil. The earthworm had no significant effects on the degradation of parent molecules of the pollutants but it significantly reduced the mineralization of the pollutants independent of the presence of the biochar. Although at an application rate of <1% the biochar strongly sorbed both pollutants, it did not significantly decrease the bioaccumulation of free dichlorophenol and phenanthrene and their metabolites by the earthworm. Our results demonstrate the complex effects of biochar on the fate, transformation, and earthworm bioaccumulation of organic pollutants in soil. They show that biochar application may not be an appropriate strategy for treating soil contaminated with hydrophobic organic pollutants and underline the importance of soil-feeding earthworms in risk assessments of biochar effects on soil remediation.

  19. Degradation of landfill gas constituents in soil

    SciTech Connect

    Kjeldsen, P.; Dalager, A.; Broholm, K.

    1996-11-01

    Landfill gas (LFG) contains high concentrations of methane which contributes to the greenhouse effect. LFG also contains aromatic hydrocarbons and chlorinated aliphatics which by emission to ambient air can be a local health threat. In addition, chlorinated aliphatics may also influence the earths ozone layer. The objectives of the study were to investigate the degradation of landfill gas constituents in LFG affected soils, and to evaluate the importance of the degradation processes to the emission. High methane oxidation potentials were found in laboratory experiments at 25{degrees}C. The degradation seemed to follow a zero order reaction kinetics, and was 3-4 times slower at 10{degrees}C as compared to 25{degrees}C. Also high degradation rates for benzene and toluene were observed. In soils sampled away from the landfill where almost no LFG contamination had been observed, longer lag phases and lower degradation rates of the two aromatic hydrocarbons were observed. Slow cometabolic degradation of trichloroethylene (TCE) and 1,1,1-trichloroethane (TCA) was observed when methane was present in the batch experiments. The rates were much lower than the rates for the aromatic hydrocarbons. In the field at Skellingsted Landfill, Denmark high methane emissions were observed in an area just outside the landfill area, probably as a result of the clay landfill covering, which has led to significant lateral migration of LFG. Indications of active methane oxidation in the field were observed by measuring soil gas profiles. By comparison of the results obtained in the laboratory with the field results it is shown, that degradation processes may have a significant effect on the emission of all the compounds studied. However the subject needs much more attention.

  20. Photochemical Degradation of Persistent Organic Pollutants in Snow and Ice

    NASA Astrophysics Data System (ADS)

    Greis, V. M.; Mahanna, K. M.; Grannas, A. M.

    2005-12-01

    The frozen surfaces of polar regions are highly reactive. The Arctic snowpack has been shown to play an important role in processing atmospheric species such as mercury, molecular halogens, organics and ozone. Several recent studies have demonstrated photochemical transformations of anthropogenic organic contaminants in ice. Unfortunately, information on transformations of organic contaminants in snow and ice is currently limited. It is important to gain a better understanding of the photochemical processes that occur, as well as identify the products of degradation, in order to assess the possible ecosystem-wide implications of pollutant degradation (i.e. generation of products more toxic than the original pollutant). With a better grasp of the photochemical processes of anthropogenic organic pollutants, an improved understanding of their effects on the environment can be obtained. In our research, we investigated both direct and indirect photodegradation of several persistent organic pollutants of concern to the Arctic environment, including aldrin, dieldrin, PCBs and hexachlorobenzene. Reactivity in both ice and liquid samples was assessed. We found selective degradation in the samples, with some of the pollutants exhibiting greater degradation in liquid samples, while others showed greater degradation in the ice samples. The methods and results of these experiments will be discussed.

  1. The impact of soil degradation on soil functioning in Europe

    NASA Astrophysics Data System (ADS)

    Montanarella, Luca

    2010-05-01

    The European Commission has presented in September 2006 its Thematic Strategy for Soil Protection.The Thematic Strategy for Soil Protection consists of a Communication from the Commission to the other European Institutions, a proposal for a framework Directive (a European law), and an Impact Assessment. The Communication (COM(2006) 231) sets the frame. It defines the relevant soil functions for Europe and identifies the major threats. It explains why further action is needed to ensure a high level of soil protection, sets the overall objective of the Strategy and explains what kind of measures must be taken. It establishes a ten-year work program for the European Commission. The proposal for a framework Directive (COM(2006) 232) sets out common principles for protecting soils across the EU. Within this common framework, the EU Member States will be in a position to decide how best to protect soil and how use it in a sustainable way on their own territory. The Impact Assessment (SEC (2006) 1165 and SEC(2006) 620) contains an analysis of the economic, social and environmental impacts of the different options that were considered in the preparatory phase of the strategy and of the measures finally retained by the Commission. Since 2006 a large amount of new evidence has allowed to further document the extensive negative impacts of soil degradation on soil functioning in Europe. Extensive soil erosion, combined with a constant loss of soil organic carbon, have raised attention to the important role soils are playing within the climate change related processes. Other important processes are related to the loss of soil biodiversity, extensive soil sealing by housing and infrastructure, local and diffuse contamination by agricultural and industrial sources, compaction due to unsustainable agricultural practices and salinization by unsustainable irrigation practices. The extended impact assessment by the European Commission has attempted to quantify in monetary terms the

  2. Chlorpyrifos pollution: its effect on brain acetylcholinesterase activity in rat and treatment of polluted soil by indigenous Pseudomonas sp.

    PubMed

    Sharma, Shelly; Singh, Partap Bir; Chadha, Pooja; Saini, Harvinder Singh

    2017-01-01

    The study was aimed to evaluate the levels of chlorpyrifos (CPF) pollution in agricultural soil of Punjab, India, its detrimental effects on acetylcholinesterase (AChE) activity in rat brain and bioremediation of soils polluted with CPF using indigenous and adapted bacterial lab isolate. The analysis revealed that soil samples of Bathinda and Amritsar regions are highly contaminated with chlorpyrifos showing 19 to 175 mg/kg concentrations of CPF. The non-targeted animals may get poisoned with CPF by its indirect dermal absorption, inhalation of toxic fumes and regular consumption of soiled food grains. The study indicated that even the lowermost concentrations of CPF, 19 and 76 mg/kg of soil found in the Amritsar and Bathinda regions respectively can significantly inhibit the AChE activity in rat brain within 24 h of its treatment. This represents the antagonistic effect of CPF on AChE which is a prime neurotransmitter present in all living beings including humans. In light of this, an attempt was made to remediate the polluted soil, a major reservoir of CPF, using Pseudomonas sp. (ChlD), an indigenous bacterial isolate. The culture efficiently degraded 10 to 100 mg/kg chlorpyrifos supplemented in the soil and utilized it as sole source of carbon and energy for its growth. Thus, this study provides a detailed insight regarding the level of CPF pollution in Punjab, its detrimental effects on mammals and bio-based solution to remediate the sites polluted with CPF.

  3. Inoculation of soil native cyanobacteria to restore arid degraded soils

    NASA Astrophysics Data System (ADS)

    Raúl Román Fernández, José; Roncero Ramos, Beatriz; Chamizo de la Piedra, Sonia; Rodríguez Caballero, Emilio; Ángeles Muñoz Martín, M.; Mateo, Pilar; Cantón Castilla, Yolanda

    2017-04-01

    Restoration projects in semiarid lands often yield poor results. Water scarcity, low soil fertility, and poor soil structure strongly limit the survival and growth of planted seedlings in these areas. Under these conditions, a previous stage that improves edaphic conditions would turn out to a successful plant restoration. By successfully colonizing arid soils, cyanobacteria naturally provide suitable edaphic conditions, enhancing water availability, soil fertility and soil stability. Furthermore, cyanobacteria can be easily isolated and cultured ex-situ to produce high quantities of biomass, representing a potential tool to restore large areas efficiently. The objective of this study was to test the effect of inoculated cyanobacteria on degraded soils at three different semiarid areas from southeast Spain: Tabernas badlands, a limestone quarry located in Gádor, and grazed grassland in Las Amoladeras (Cabo de Gata). Soil native cyanobacteria belonging to three representative N-fixing genera (Nostoc, Scytonema and Tolypothrix) were isolated from such soils and cultured in BG110 medium. Each strain was inoculated (6 g m-2), separately and mixed (all in the same proportion), on Petri dishes with 80 g of each soil. Biocrust development was monitored during 3 months in these soils under laboratory conditions, at a constant temperature of 25oC. During the experiment, two irrigation treatments were applied simulating a dry (180 mm) and a wet (360 mm) rainfall year (average recorded in the study sites). After 3 months, net CO2 flux, spectral response and soil surface microtopography (1 mm spatial resolution) of inoculated and control soils was measured under wet conditions, all of them as a surrogate of biocrust development. Samples of the surface crust were collected in order to determine total soil organic carbon (SOC) content. The inoculated soils showed positive values of net CO2 flux, thus indicating a net CO2 uptake, whereas control soils showed CO2 fluxes closed to

  4. Mixotrophic cyanobacteria and microalgae as distinctive biological agents for organic pollutant degradation.

    PubMed

    Subashchandrabose, Suresh R; Ramakrishnan, Balasubramanian; Megharaj, Mallavarapu; Venkateswarlu, Kadiyala; Naidu, Ravi

    2013-01-01

    Millions of natural and synthetic organic chemical substances are present in both soil and aquatic environments. Toxicity and/or persistence determine the polluting principle of these substances. The biological responses to these pollutants include accumulation and degradation. The responses of environments with organic pollutants are perceptible from the dwindling degradative abilities of microorganisms. Among different biological members, cyanobacteria and microalgae are highly adaptive through many eons, and can grow autotrophically, heterotrophically or mixotrophically. Mixotrophy in cyanobacteria and microalgae can provide many competitive advantages over bacteria and fungi in degrading organic pollutants. Laboratory culturing of strict phototrophic algae has limited the realization of their potential as bioremediation agents. In the natural assemblages, mixotrophic algae can contribute to sequestration of carbon, which is otherwise emitted as carbon dioxide to the atmosphere under heterotrophic conditions by other organisms. Molecular methods and metabolic and genomic information will help not only in identification and selection of mixotrophic species of cyanobacteria and microalgae with capabilities to degrade organic pollutants but also in monitoring the efficiency of remediation efforts under the field conditions. These organisms are relatively easier for genetic engineering with desirable traits. This review presents a new premise from the literature that mixotrophic algae and cyanobacteria are distinctive bioremediation agents with capabilities to sequester carbon in the environment. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Comparative metagenomic analysis of PAH degradation in soil by a mixed microbial consortium.

    PubMed

    Zafra, German; Taylor, Todd D; Absalón, Angel E; Cortés-Espinosa, Diana V

    2016-11-15

    In this study, we used a taxonomic and functional metagenomic approach to analyze some of the effects (e.g. displacement, permanence, disappearance) produced between native microbiota and a previously constructed Polycyclic Aromatic Hydrocarbon (PAH)-degrading microbial consortium during the bioremediation process of a soil polluted with PAHs. Bioaugmentation with a fungal-bacterial consortium and biostimulation of native microbiota using corn stover as texturizer produced appreciable changes in the microbial diversity of polluted soils, shifting native microbial communities in favor of degrading specific populations. Functional metagenomics showed changes in gene abundance suggesting a bias towards aromatic hydrocarbon and intermediary degradation pathways, which greatly favored PAH mineralization. In contrast, pathways favoring the formation of toxic intermediates such as cytochrome P450-mediated reactions were found to be significantly reduced in bioaugmented soils. PAH biodegradation in soil using the microbial consortium was faster and reached higher degradation values (84% after 30 d) as a result of an increased co-metabolic degradation when compared with other mixed microbial consortia. The main differences between inoculated and non-inoculated soils were observed in aromatic ring-hydroxylating dioxygenases, laccase, protocatechuate, salicylate and benzoate-degrading enzyme genes. Based on our results, we propose that several concurrent metabolic pathways are taking place in soils during PAH degradation.

  6. Cases Studies of Irrigated Soil Degradation and Progradation

    NASA Astrophysics Data System (ADS)

    Zeyliger, Anatoly; Kust, German; Rozov, Sergey; Stoma, Galina

    2013-04-01

    Waterlogging and salination, along with interaction with other degradation processes, have not only caused the collapse of irrigation-based societies in the past, but are indeed threatening the viability of irrigation at present. The problem is global in scope. Decimation of natural ecosystems, deterioration of soil productivity depletion and pollution of water resources, and conflicts over dwindling supplies have become international problems closely linked with extension of irrigation development to large scale and associated impact to soil fertility and surrounding environment. Practical experience and scientific research done in the frame of FP6 DESIRE project provided an affirmative answer to the question - can irrigated agriculture be sustained for long time. In present contribution two case studies will be discussed and analysed in scope to compare different irrigation practises used for about 35 years and their impact to soil fertility. Investigated areas of both case studies are situated in the same Saratov Region of Russia at the left bank of middle part of Volga River with distance between about 100 km. First case study was developed during 2009-2010 by field trials at irrigated and surrounded areas of agricultural farms situated at Privolghskaya Irrigation System (Marksovsky District). Second case study was developed during summer of 2011 by field trial at experimental farm of research institute called VolgNIIGiM (Enghelsky District). During fields trail soil maps of both case studies were developed and compared with soil maps of the same areas done at 1970th before irrigation projects at both areas were started. Results of soil map comparison are showing that in the territory of first case study considerable soil degradation is taken place, but in the territory of the second case study a substantial soil progradation is taken place. Thus is supported by the time series of ground water monitoring at both irrigated areas. Obtained results will be

  7. Understanding Plant-Microbe Interactions for Phytoremediation of Petroleum-Polluted Soil

    PubMed Central

    Nie, Ming; Wang, Yijing; Yu, Jiayi; Xiao, Ming; Jiang, Lifen; Yang, Ji; Fang, Changming; Chen, Jiakuan; Li, Bo

    2011-01-01

    Plant-microbe interactions are considered to be important processes determining the efficiency of phytoremediation of petroleum pollution, however relatively little is known about how these interactions are influenced by petroleum pollution. In this experimental study using a microcosm approach, we examined how plant ecophysiological traits, soil nutrients and microbial activities were influenced by petroleum pollution in Phragmites australis, a phytoremediating species. Generally, petroleum pollution reduced plant performance, especially at early stages of plant growth. Petroleum had negative effects on the net accumulation of inorganic nitrogen from its organic forms (net nitrogen mineralization (NNM)) most likely by decreasing the inorganic nitrogen available to the plants in petroleum-polluted soils. However, abundant dissolved organic nitrogen (DON) was found in petroleum-polluted soil. In order to overcome initial deficiency of inorganic nitrogen, plants by dint of high colonization of arbuscular mycorrhizal fungi might absorb some DON for their growth in petroleum-polluted soils. In addition, through using a real-time polymerase chain reaction method, we quantified hydrocarbon-degrading bacterial traits based on their catabolic genes (i.e. alkB (alkane monooxygenase), nah (naphthalene dioxygenase) and tol (xylene monooxygenase) genes). This enumeration of target genes suggests that different hydrocarbon-degrading bacteria experienced different dynamic changes during phytoremediation and a greater abundance of alkB was detected during vegetative growth stages. Because phytoremediation of different components of petroleum is performed by different hydrocarbon-degrading bacteria, plants’ ability of phytoremediating different components might therefore vary during the plant life cycle. Phytoremediation might be most effective during the vegetative growth stages as greater abundances of hydrocarbon-degrading bacteria containing alkB and tol genes were observed

  8. Understanding plant-microbe interactions for phytoremediation of petroleum-polluted soil.

    PubMed

    Nie, Ming; Wang, Yijing; Yu, Jiayi; Xiao, Ming; Jiang, Lifen; Yang, Ji; Fang, Changming; Chen, Jiakuan; Li, Bo

    2011-03-18

    Plant-microbe interactions are considered to be important processes determining the efficiency of phytoremediation of petroleum pollution, however relatively little is known about how these interactions are influenced by petroleum pollution. In this experimental study using a microcosm approach, we examined how plant ecophysiological traits, soil nutrients and microbial activities were influenced by petroleum pollution in Phragmites australis, a phytoremediating species. Generally, petroleum pollution reduced plant performance, especially at early stages of plant growth. Petroleum had negative effects on the net accumulation of inorganic nitrogen from its organic forms (net nitrogen mineralization (NNM)) most likely by decreasing the inorganic nitrogen available to the plants in petroleum-polluted soils. However, abundant dissolved organic nitrogen (DON) was found in petroleum-polluted soil. In order to overcome initial deficiency of inorganic nitrogen, plants by dint of high colonization of arbuscular mycorrhizal fungi might absorb some DON for their growth in petroleum-polluted soils. In addition, through using a real-time polymerase chain reaction method, we quantified hydrocarbon-degrading bacterial traits based on their catabolic genes (i.e. alkB (alkane monooxygenase), nah (naphthalene dioxygenase) and tol (xylene monooxygenase) genes). This enumeration of target genes suggests that different hydrocarbon-degrading bacteria experienced different dynamic changes during phytoremediation and a greater abundance of alkB was detected during vegetative growth stages. Because phytoremediation of different components of petroleum is performed by different hydrocarbon-degrading bacteria, plants' ability of phytoremediating different components might therefore vary during the plant life cycle. Phytoremediation might be most effective during the vegetative growth stages as greater abundances of hydrocarbon-degrading bacteria containing alkB and tol genes were observed at

  9. Soil quality of a degraded urban area

    NASA Astrophysics Data System (ADS)

    Panico, Speranza; Memoli, Valeria; Maisto, Giulia; De Marco, Anna

    2017-04-01

    Human activities cause modifications of the soil characteristics, leading to a significant reduction of the soil fertility and quality. The aim of this study was to evaluate the relationships between microbial activity or biomass and chemical characteristics (i.e. heavy metal and organic matter contents) of a degraded urban soil. The study area is located in an urban park (about 10 ha, called Quarantena) near to the Fusaro Lake of Campi Flegrei (Southern Italy); the Park was established in 1953 to shelter animals coming from any place of the Planet and execute veterinary checks before their delivery to different European zoos. In 1997, the park was abandoned and nowadays in it a large amount of urban wastes accumulates. Surface soils (0-10 cm) were sampled at three points: two of them covered by Holm Oak specimens (P1 and P2) and one covered by herbaceous species, particularly legumes (P3). P1 was localized at the border of the park and next to a busy road; P2 at the centre of the Quarantena Park; P3 at a gap area near the Fusaro Lake. The results showed that the soil sampled at P1 showed the highest Cr and Ni concentrations; the soil sampled at P3 had high levels of Cu and Pb, exceeding the threshold values of 100 µg g-1 d.w. fixed by the Italian law for urban soils, probably due to boat traffic, fishing practice and agricultural activities; the soil sampled at P2 had intermediate values of metal concentrations but the highest amount of organic matter (more than 20% d.w.). Despite of metal contamination, P1 and P3 showed higher soil microbial biomass and activity as compared to P2. Therefore, at this site, the organic matter accumulation could be due to the scarce litter degradation. In conclusion, although the studied area was not too large, a wide heterogeneity of soil quality (in terms of the investigated chemical and biological characteristics) was detected, depending on the local human impact.

  10. Photochemical Degradation of Organic Pollutants in Liquid Water and Ice

    NASA Astrophysics Data System (ADS)

    Sprenkle, A. M.; Grannas, A. M.

    2006-12-01

    Arctic snow and ice play an important role as reactive media in the environment. A variety of species are photochemically generated from snow/ice, including carbonyl compounds, alkyl halides, molecular halogens, and nitrogen oxides. However, the fate of anthropogenic organic pollutants in snow and ice is largely unknown. Volatile pollutants evaporate from lower, warmer latitudes and condense out in the higher, colder latitudes by a process known as global distillation, leading to enhanced concentrations of a variety of pollutants in polar regions. Here we present recent results of photochemical degradation studies of several important organic pollutants including aldrin, dieldrin, hexachlorobenzene, and 3,3',4,5'-tetrachlorobiphenyl. Direct and indirect (with H2O2) pathways were studied in both liquid water and ice forms. Aldrin and 3,3',4,5'-tetrachlorobiphenyl have shown the most reactivity, both degrading significantly via the direct and indirect pathway in liquid water and ice. Dieldrin has shown reactivity under both direct and indirect liquid conditions, while HCB is only reactive under indirect liquid conditions. These results indicate that ice can serve as an important reactive surface for anthropogenic organic pollutants. Snow/ice photochemistry should be included in models of pollutant fate, but further studies are necessary to determine which pollutants are most affected by ice photochemistry under typical environmental conditions.

  11. Degradation of environmental pollutants by Trametes trogii.

    PubMed

    Haglund, C; Levín, L; Forchiassin, F; López, M; Viale, A

    2002-01-01

    The ability of the ligninolytic fungus Trametes trogii to degrade in vitro different xenobiotics (PCBs, PAHs and dyes) was evaluated. Either 200 ppm of a PCB mixture (Aroclor 1150) or 160 ppm of an industrial PAH mixture (10% V/V of PAHs, principal components hexaethylbenzene, naphthalene, 1-methyl naphthalene, acenaphthylene, anthracene, fluorene and phenanthrene), were added to trophophasic and idiophasic cultures growing in a nitrogen limited mineral medium (glucose/asparagine) and in a complex medium (malt extract/glucose). Gas-liquid chromatography proved that within 7 to 12 d more than 90% of the organopollutants added were removed. The decrease in absorbance at 620 nm demonstrated that cultures of this fungus were able to transform 80% of the dye Anthraquinone-blue (added at a concentration of 50 ppm) in 1.5 h. Enzyme estimations indicated high activity of laccase (up to 0.55 U/mL), as well as lower production of manganese-peroxidase. Laccase activity, detected in all the conditions assayed, could be implicated in the degradation of these organopollutants. Considering the results obtained, T. trogii seems promising for detoxification.

  12. Ultrasound based AOP for emerging pollutants: from degradation to mechanism.

    PubMed

    Rayaroth, Manoj P; Aravind, Usha K; Aravindakumar, Charuvila T

    2017-03-01

    Ultrasound is known to degrade organic compounds by pyrolysis and by the reaction of free radicals. In this work, sonolytic degradation of an identified water pollutant, coomassie brilliant blue (CBB), has been carried out in pure water as well as in river water. In the case of pure water, 90 % degradation was obtained after 30 min of sonication (350 kHz frequency, 60 W power), whereas in river water, the same efficiency was achieved only after 90 min. The degradation was also performed in the presence of varying concentration of (10-100 mg L(-1)) inorganic ions such as chloride, sulfate, nitrate, bicarbonate, and carbonate ions which were detected in the river water sample. Higher concentration of chloride enhanced the degradation due to the salting out mechanism. The enhancement of degradation in the presence of nitrate is mainly due to the change in the surface potential at the interface of the cavitating bubble. Bicarbonate ion and carbonate ion enhanced the degradation due to the involvement of carbonate radicals. A possible degradation mechanism is proposed based on the product profile determined by LC-Q-ToF-MS. The low efficiency of degradation in river water compared to that in pure water is likely due to the increased rate of bubble dissolution or escape of bubbles (degassing effect), and the scavenging of (•)OH by the organic content (high chemical oxygen demand (COD)).

  13. Does metal pollution matter with C retention by rice soil?

    PubMed Central

    Bian, Rongjun; Cheng, Kun; Zheng, Jufeng; Liu, Xiaoyu; Liu, Yongzhuo; Li, Zhipeng; Li, Lianqing; Smith, Pete; Pan, Genxing; Crowley, David; Zheng, Jinwei; Zhang, Xuhui; Zhang, Liangyun; Hussain, Qaiser

    2015-01-01

    Soil respiration, resulting in decomposition of soil organic carbon (SOC), emits CO2 to the atmosphere and increases under climate warming. However, the impact of heavy metal pollution on soil respiration in croplands is not well understood. Here we show significantly increased soil respiration and efflux of both CO2 and CH4 with a concomitant reduction in SOC storage from a metal polluted rice soil in China. This change is linked to a decline in soil aggregation, in microbial abundance and in fungal dominance. The carbon release is presumably driven by changes in carbon cycling occurring in the stressed soil microbial community with heavy metal pollution in the soil. The pollution-induced increase in soil respiration and loss of SOC storage will likely counteract efforts to increase SOC sequestration in rice paddies for climate change mitigation. PMID:26272277

  14. Does metal pollution matter with C retention by rice soil?

    PubMed

    Bian, Rongjun; Cheng, Kun; Zheng, Jufeng; Liu, Xiaoyu; Liu, Yongzhuo; Li, Zhipeng; Li, Lianqing; Smith, Pete; Pan, Genxing; Crowley, David; Zheng, Jinwei; Zhang, Xuhui; Zhang, Liangyun; Hussain, Qaiser

    2015-08-14

    Soil respiration, resulting in decomposition of soil organic carbon (SOC), emits CO2 to the atmosphere and increases under climate warming. However, the impact of heavy metal pollution on soil respiration in croplands is not well understood. Here we show significantly increased soil respiration and efflux of both CO2 and CH4 with a concomitant reduction in SOC storage from a metal polluted rice soil in China. This change is linked to a decline in soil aggregation, in microbial abundance and in fungal dominance. The carbon release is presumably driven by changes in carbon cycling occurring in the stressed soil microbial community with heavy metal pollution in the soil. The pollution-induced increase in soil respiration and loss of SOC storage will likely counteract efforts to increase SOC sequestration in rice paddies for climate change mitigation.

  15. The CO2 emission in urbanic soils in the conditions of intensive technogenic pollution

    NASA Astrophysics Data System (ADS)

    Deviatova, Tatiana; Alaeva, Liliia; Negrobova, Elena; Kramareva, Tatiana

    2017-04-01

    . Thus, the technogenic impact on the soil cover of the city greatly affects the emission of CO2 from the soil. Increasing in industrially polluted soils is associated with increased mineralization of organic matter and degradation of humus. You can put that in terms of pollution, increased carbon loss depends on changes in the metabolism of soil organisms.

  16. Sorption and degradation of fipronil in flooded anaerobic rice soils.

    PubMed

    Doran, Gregory; Eberbach, Philip; Helliwell, Stuart

    2009-11-11

    The fate of fipronil in flooded, reductive rice soils was modeled using a conceptual model. Rate constants for the various sorption and degradation processes were calculated from experimental studies involving intact soil cores, and the reductive degradation constant was used to calculate half-lives for fipronil on each soil. The data predicted that fipronil was subject to rapid, reductive degradation or immediate sorption to the soil and any sorbed fipronil desorbed was reductively degraded. The reductive metabolite, fipronil sulfide, accumulated over the 184 day duration of the experiment and sorbed rapidly to the soil, where it accumulated and did not appear to degrade. Neither fipronil nor fipronil sulfide was found beyond the top 1 cm of soil in Yanco soil, while a small amount of each chemical was found up to 4 cm deep in the Coleambally soil profile.

  17. Desorption and Degradation of Organic Contaminants in Soil by Microwave Radiation

    NASA Astrophysics Data System (ADS)

    Jeong, S.; Kim, H.

    2011-12-01

    Many military bases located in the down towns of South Korea are asked to move outside of the urban areas due to the growth of the cities. During the past 60 years, many military bases of South Korea have been operated and according to that, parts of the soil have been polluted with organic contaminants such as total petroleum hydrocarbons (TPH), solvents, etc. In the case of South Korea, rapid remediation of the contaminated soil is required for efficient development of land. Thermal desorption is one of the most efficient and rapid remediation methods for polluted soil to clean up, but the fact is it consumes a lot of energy. In this study, desorption and degradation of organic contaminants in soil using microwave radiation is investigated in order to energy efficient and rapid remediation technique development. Polluted soil collected from a military base was remediated in the laboratory using a home made microwave reactor. In order to study uncontaminated soil was also intentionally contaminated with diesel, TCE, and phenanthrene, respectively, for a month and used for experiments. Contaminated soil places within stainless steel reactor and microwave radiates with nitrogen gas. Emitted gas from the reactor was collected with methanol or acetonitrile solution every 3 minute for 15 minutes, and analyzed with GC, HPLC, GC/MS, respectively. The TPH contaminated soil from military base desorbed initially light hydrocarbon (retention time < 12 minutes) but, after 9 minutes of the microwave radiation discharged heavy hydrocarbon mostly. The desorption properties of the TPH contaminated soil from the military base will be compared to those of intentionally contaminated soil in the laboratory for a month. Based on the results of the collected gas analysis, degradation by products of the TCE and phenanthrene were not observed after 15 minute microwave radiation on the contaminated soil. In order to enhance microwave reaction, iron powder, graphite will be added to the

  18. Bioremediation of hydrocarbon degradation in a petroleum-contaminated soil and microbial population and activity determination.

    PubMed

    Wu, Manli; Li, Wei; Dick, Warren A; Ye, Xiqiong; Chen, Kaili; Kost, David; Chen, Liming

    2017-02-01

    Bioremediation of hydrocarbon degradation in petroleum-polluted soil is carried out by various microorganisms. However, little information is available for the relationships between hydrocarbon degradation rates in petroleum-contaminated soil and microbial population and activity in laboratory assay. In a microcosm study, degradation rate and efficiency of total petroleum hydrocarbons (TPH), alkanes, and polycyclic aromatic hydrocarbons (PAH) in a petroleum-contaminated soil were determined using an infrared photometer oil content analyzer and a gas chromatography mass spectrometry (GC-MS). Also, the populations of TPH, alkane, and PAH degraders were enumerated by a modified most probable number (MPN) procedure, and the hydrocarbon degrading activities of these degraders were determined by the Biolog (MT2) MicroPlates assay. Results showed linear correlations between the TPH and alkane degradation rates and the population and activity increases of TPH and alkane degraders, but no correlation was observed between the PAH degradation rates and the PAH population and activity increases. Petroleum hydrocarbon degrading microbial population measured by MPN was significantly correlated with metabolic activity in the Biolog assay. The results suggest that the MPN procedure and the Biolog assay are efficient methods for assessing the rates of TPH and alkane, but not PAH, bioremediation in oil-contaminated soil in laboratory.

  19. Physiologically based pharmacokinetic (PB-PK) modeling of indoor air pollutant degradation by houseplants

    SciTech Connect

    Smith, E.K.; El-Masri, H.A.; Tessari, J.D.; Yang, R.S.H.; Reardon, K.F.

    1994-12-31

    In the US, indoor air pollutant levels commonly exceed outdoor levels by a factor of 7 or more. Since people typically spend more than 90% percent of their time indoors, indoor air pollution has the potential for greater consequences on human health. A NASA researcher has reported that certain houseplants will reduce closed chamber concentrations of common indoor air pollutants by more than 75%. The authors are expanding this research; common houseplants and PB-PK modeling can be combined to predict the reduction rates of frequently detected indoor air pollutants, and be used as an environmental remediation approach. The approach to measuring plant gas uptake of indoor air pollutants provides a more quantitative and controlled approach than previous studies. Construction of the closed chamber system linked to a computerized gas chromatograph is complete. This system measures plant uptake of volatile organic chemicals. In experiments using initial concentrations of 21--2,100 ppm of the common indoor air pollutant trichloroethylene (TCE) with peace lily in soil, between 27--34% of TCE was removed during a 12-hour test period. In similar experiments, plants in abiotic potting media removed only 4--13% of TCE from the closed system, suggesting that microbial degradation or soil adsorption of TCE are significant factors.

  20. Hydrazine degradation and its effect on microbial activity in soil

    SciTech Connect

    Ou, L.T.; Street, J.J.

    1987-01-01

    Considerable information has been accumulated on the toxicity of hydrazine to soil bacterial cultures and on the degradation of hydrazne by soil bacterial cultures. The activities of the autotrophic nitrifiers Nitrosomonas and Nitrobacter and of denitrifying bacteria, and the growth of Enterobacter cloacae, were all inhibited by hydrazine. An enzyme system has been found in heterotrophic N/sub 2/-fixing bacteria capable of degrading hydrazine. Information concerning the effect of hydrazine on microbial activity in soils is not available, however. Accidental spills to soil can occur during transportation and storage. Therefore, this study was initiated to determine degradation rates of hydrazine in soils and its effect on soil microbial activity.

  1. National approaches to evaluation of the degree of soil degradation

    NASA Astrophysics Data System (ADS)

    Molchanov, E. N.; Savin, I. Yu.; Yakovlev, A. S.; Bulgakov, D. S.; Makarov, O. A.

    2015-11-01

    Approaches to evaluation of the degree of soil degradation and the related normative documents applied by specialists from state institutes for land management of the former Soviet Union in the course of largeand medium-scale soil surveys in the 1960s-1990s are analyzed. It is shown that the types and rates of soil degradation were specified without proper consideration for the taxonomic position of particular soils. Reference (nondegraded) soils were not clearly defined, which made it difficult to judge the degree of soil degradation by means of a comparative analysis of degraded and nondegraded soils. Such reference soils are suggested for several types of soil degradation (dehumification, compaction, depletion of nutrients, etc.). Additional diagnostic criteria of the degree of soil degradation caused by wind and water erosion, waterlogging, swamping, and other adverse processes are specified. The study of qualitative and quantitative changes in the soil properties during the post-Soviet period is important for the development of land monitoring system and for the analysis of economic aspects of land degradation. To ensure reliability of data on changes in the soil properties and soil cover patterns, possible errors related to incorrect comparison of the data obtained by traditional and modern approaches should be taken into account.

  2. Zinc oxide tetrapods as efficient photocatalysts for organic pollutant degradation

    NASA Astrophysics Data System (ADS)

    Liu, Fangzhou; Leung, Yu Hang; Djurisić, Aleksandra B.; Liao, Changzhong; Shih, Kaimin

    2014-03-01

    Bisphenol A (BPA) and other organic pollutants from industrial wastewater have drawn increasing concern in the past decades regarding their environmental and biological risks, and hence developing strategies of effective degradation of BPA and other organic pollutants is imperative. Metal oxide nanostructures, in particular titanium oxide (TiO2) and zinc oxide (ZnO), have been demonstrated to exhibit efficient photodegradation of various common organic dyes. ZnO tetrapods are of special interest due to their low density of native defects which consequently lead to lower recombination losses and higher photocatalytic efficiency. Tetrapods can be obtained by relatively simple and low-cost vapor phase deposition in large quantity; the micron-scale size would also be advantageous for catalyst recovery. In this study, the photodegradation of BPA with ZnO tetrapods and TiO2 nanostructures under UV illumination were compared. The concentration of BPA dissolved in DI water was analyzed by high-performance liquid chromatography (HPLC) at specified time intervals. It was observed that the photocatalytic efficiency of ZnO tetrapods eventually surpassed Degussa P25 in free-standing form, and more than 80% of BPA was degraded after 60 min. Photodegradation of other organic dye pollutants by tetrapods and P25 were also examined. The superior photocatalytic efficiency of ZnO tetrapods for degradation of BPA and other organic dye pollutants and its correlation with the material properties were discussed.

  3. Correlations between PAH bioavailability, degrading bacteria, and soil characteristics during PAH biodegradation in five diffusely contaminated dissimilar soils.

    PubMed

    Crampon, M; Bureau, F; Akpa-Vinceslas, M; Bodilis, J; Machour, N; Le Derf, F; Portet-Koltalo, F

    2014-01-01

    The natural biodegradation of seven polycyclic aromatic hydrocarbons (PAHs) by native microorganisms was studied in five soils from Normandy (France) from diffusely polluted areas, which can also pose a problem in terms of surfaces and amounts of contaminated soils. Bioavailability tests using cyclodextrin-based extractions were performed. The natural degradation of low molecular weight (LMW) PAHs was not strongly correlated to their bioavailability due to their sorption to geosorbents. Conversely, the very low degradation of high molecular weight (HMW) PAHs was partly correlated to their poor availability, due to their sorption on complexes of organic matter and kaolinites or smectites. A principal component analysis allowed us to distinguish between the respective degradation behaviors of LMW and HMW PAHs. LMW PAHs were degraded in less than 2-3 months and were strongly influenced by the relative percentage of phenanthrene-degrading bacteria over total bacteria in soils. HMW PAHs were not significantly degraded, not only because they were less bioavailable but also because of a lack of degrading microorganisms. Benzo[a]pyrene stood apart since it was partly degraded in acidic soils, probably because of a catabolic cooperation between bacteria and fungi.

  4. [Componential composition of chlororganic pollutants and state of soil microbial cenosis in soil from burial place of waste].

    PubMed

    Iamborko, N A; Iutyns'ka, H O; Levchuk, I V; Pindrus, A A

    2013-01-01

    The authors have identified 25 chemical pollutants in soil and 12--in the chemical composition of technical waste from chemical production. Broad spectrum of pollutants and their degradation products (26 chemical components) have been also detected outside the proving ground (2 km). This fact evidences for active spreading of chlororganic toxins into neighboring areas. Abnormality in functional activity and functions of soil microbial cenosis of the proving ground has been established: the number of oligonitrophillus, ammoniating, phosphate-mobilizing, amylolytic and pedotrophic microorganisms. Abnormalities of functional activity were manifested in the 1.6-1.9-fold augmentation of basal respiration and deterioration of substrate-induced respiration in comparison with control variant.

  5. Degradation of roxarsone in a silt loam soil and its toxicity assessment.

    PubMed

    Liang, Tengfang; Ke, Zhengchen; Chen, Qing; Liu, Li; Chen, Guowei

    2014-10-01

    The land application of poultry or swine litter, containing large amounts of roxarsone, causes serious arsenic pollution in soil. Understanding biotransformation process of roxarsone and its potential risks favors proper disposal of roxarsone-contaminated animal litter, yet remains not achieved. We report an experimental study of biotransformation process of roxarsone in a silt loam soil under various soil moisture and temperature conditions, and the toxicity of roxarsone and its products from degradation. Results showed that soil moisture and higher temperature promoted roxarsone degradation, associating with emergent pentavalent arsenic. Analysis of fluorescein diacetate (FDA) hydrolysis activity revealed that roxarsone does not exert acute toxic on soil microbes. With the release of inorganic arsenic, FDA hydrolysis activity was inhibited gradually, as evidenced by ecotoxicological assessment using Photobacterium leiognathi. The results shade new lights on the dynamic roxarsone biotransformation processes in soil, which is important for guiding appropriate disposal of poultry or swine litter in the environment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Heavy Metal Pollution Enhances Soil Respiration and Reduces Carbon Storage in a Chinese Paddy Soil

    NASA Astrophysics Data System (ADS)

    Pan, Genxing; Li, Zhipeng; Liu, Yongzhuo; Smith, Pete; Crowley, David; Zheng, Jufeng

    2010-05-01

    China's paddy soils are crucial both for food security through high cereal productivity, and for climate mitigation through high soil carbon storage. These functions are increasingly threatened by widespread heavy metal pollution, resulting from rapid industrial development. Heavy metal-polluted soils generally have a reduced microbial biomass and reduced soil respiration, as well as reduced functional diversity through changes in microbial community structure. Here we show that heavy metal pollution enhances soil respiration and CO2 efflux from a Chinese rice paddy soil, and leads to a soil organic carbon (SOC) loss, which is correlated with a decline in the fungal-to-bacterial ratio of the reduced soil microbial community. The pollution-induced SOC loss could offset 70% of the yearly SOC increase from China's paddy soils. Thus, heavy metal pollution impacts long term productivity and the potential for C sequestration in China's paddy soils.

  7. Monitoring the soil degradation by Metastatistical Analysis

    NASA Astrophysics Data System (ADS)

    Oleschko, K.; Gaona, C.; Tarquis, A.

    2009-04-01

    The effectiveness of fractal toolbox to capture the critical behavior of soil structural patterns during the chemical and physical degradation was documented by our numerous experiments (Oleschko et al., 2008 a; 2008 b). The spatio-temporal dynamics of these patterns was measured and mapped with high precision in terms of fractal descriptors. All tested fractal techniques were able to detect the statistically significant differences in structure between the perfect spongy and massive patterns of uncultivated and sodium-saline agricultural soils, respectively. For instance, the Hurst exponent, extracted from the Chernozeḿ micromorphological images and from the time series of its physical and mechanical properties measured in situ, detected the roughness decrease (and therefore the increase in H - from 0.17 to 0.30 for images) derived from the loss of original structure complexity. The combined use of different fractal descriptors brings statistical precision into the quantification of natural system degradation and provides a means for objective soil structure comparison (Oleschko et al., 2000). The ability of fractal parameters to capture critical behavior and phase transition was documented for different contrasting situations, including from Andosols deforestation and erosion, to Vertisols high fructuring and consolidation. The Hurst exponent is used to measure the type of persistence and degree of complexity of structure dynamics. We conclude that there is an urgent need to select and adopt a standardized toolbox for fractal analysis and complexity measures in Earth Sciences. We propose to use the second-order (meta-) statistics as subtle measures of complexity (Atmanspacher et al., 1997). The high degree of correlation was documented between the fractal and high-order statistical descriptors (four central moments of stochastic variable distribution) used to the system heterogeneity and variability analysis. We proposed to call this combined fractal

  8. Restoring and Enhancing Productivity of Degraded Tephra-Derived Soils

    Treesearch

    Chuck Bulmer; Jim Archuleta; Mike Curran

    2007-01-01

    Soil restoration (sometimes termed enhancement) is an important strategy for sustaining the productivity of managed forest landscapes. Tephra-derived soils have unique physical and chemical characteristics that affect their response to disturbance and restoration. A variety of factors reduce forest productivity on degraded soils. Site-specific information on soil...

  9. Interactions of earthworms with Atrazine-degrading bacteria in an agricultural soil.

    PubMed

    Kersanté, Anne; Martin-Laurent, Fabrice; Soulas, Guy; Binet, Françoise

    2006-08-01

    In the last 10 years, accelerated mineralization of Atrazine (2-chloro-ethylamino-6-isopropylamino-s-triazine) has been evidenced in agricultural soils repeatedly treated with this herbicide. Here, we report on the interaction between earthworms, considered as soil engineers, and the Atrazine-degrading community. The impact of earthworm macrofauna on Atrazine mineralization was assessed in representative soil microsites of earthworm activities (gut contents, casts, burrow linings). Soil with or without earthworms, namely the anecic species Lumbricus terrestris and the endogenic species Aporrectodea caliginosa, was either inoculated or not inoculated with Pseudomonas sp. ADP, an Atrazine-degrading strain, and was either treated or not treated with Atrazine. The structure of the bacterial community, the Atrazine-degrading activity and the abundance of atzA, B and C sequences in soil microsites were investigated. Atrazine mineralization was found to be reduced in representative soil microsites of earthworm activities. Earthworms significantly affected the structure of soil bacterial communities. They also reduced the size of the inoculated population of Pseudomonas sp. ADP, thereby contributing to the diminution of the Atrazine-degrading genetic potential in representative soil microsites of earthworm activities. This study illustrates the regulation produced by the earthworms on functional bacterial communities involved in the fate of organic pollutants in soils.

  10. Potential of Polycyclic Aromatic Hydrocarbon-Degrading Bacterial Isolates to Contribute to Soil Fertility.

    PubMed

    Bello-Akinosho, Maryam; Makofane, Rosina; Adeleke, Rasheed; Thantsha, Mapitsi; Pillay, Michael; Chirima, George Johannes

    2016-01-01

    Restoration of polycyclic aromatic hydrocarbon- (PAH-) polluted sites is presently a major challenge in agroforestry. Consequently, microorganisms with PAH-degradation ability and soil fertility improvement attributes are sought after in order to achieve sustainable remediation of polluted sites. This study isolated PAH-degrading bacteria from enriched cultures of spent automobile engine-oil polluted soil. Isolates' partial 16S rRNA genes were sequenced and taxonomically classified. Isolates were further screened for their soil fertility attributes such as phosphate solubilization, atmospheric nitrogen fixation, and indoleacetic acid (IAA) production. A total of 44 isolates were obtained and belong to the genera Acinetobacter, Arthrobacter, Bacillus, Flavobacterium, Microbacterium, Ochrobactrum, Pseudomonas, Pseudoxanthomonas, Rhodococcus, and Stenotrophomonas. Data analysed by principal component analysis showed the Bacillus and Ochrobactrum isolates displayed outstanding IAA production. Generalized linear modelling statistical approaches were applied to evaluate the contribution of the four most represented genera (Pseudomonas, Acinetobacter, Arthrobacter, and Rhodococcus) to soil fertility. The Pseudomonas isolates were the most promising in all three soil fertility enhancement traits evaluated and all isolates showed potential for one or more of the attributes evaluated. These findings demonstrate a clear potential of the isolates to participate in restorative bioremediation of polluted soil, which will enhance sustainable agricultural production and environmental protection.

  11. Potential of Polycyclic Aromatic Hydrocarbon-Degrading Bacterial Isolates to Contribute to Soil Fertility

    PubMed Central

    Chirima, George Johannes

    2016-01-01

    Restoration of polycyclic aromatic hydrocarbon- (PAH-) polluted sites is presently a major challenge in agroforestry. Consequently, microorganisms with PAH-degradation ability and soil fertility improvement attributes are sought after in order to achieve sustainable remediation of polluted sites. This study isolated PAH-degrading bacteria from enriched cultures of spent automobile engine-oil polluted soil. Isolates' partial 16S rRNA genes were sequenced and taxonomically classified. Isolates were further screened for their soil fertility attributes such as phosphate solubilization, atmospheric nitrogen fixation, and indoleacetic acid (IAA) production. A total of 44 isolates were obtained and belong to the genera Acinetobacter, Arthrobacter, Bacillus, Flavobacterium, Microbacterium, Ochrobactrum, Pseudomonas, Pseudoxanthomonas, Rhodococcus, and Stenotrophomonas. Data analysed by principal component analysis showed the Bacillus and Ochrobactrum isolates displayed outstanding IAA production. Generalized linear modelling statistical approaches were applied to evaluate the contribution of the four most represented genera (Pseudomonas, Acinetobacter, Arthrobacter, and Rhodococcus) to soil fertility. The Pseudomonas isolates were the most promising in all three soil fertility enhancement traits evaluated and all isolates showed potential for one or more of the attributes evaluated. These findings demonstrate a clear potential of the isolates to participate in restorative bioremediation of polluted soil, which will enhance sustainable agricultural production and environmental protection. PMID:27774456

  12. Enhanced microbial degradation of deethylatrazine in atrazine-history soils

    SciTech Connect

    Kruger, E.L.; Chaplin, J.A.; Anderson, T.A.

    1995-12-01

    Persistence and degradation of deethylatrazine, the primary metabolite of atrazine, was measured in soil with atrazine history (15 consecutive years of atrazine application) and no atrazine history (no atrazine application for 15 consecutive years). Uniformly ring-labeled {sup 14}C-deethylatrazine was applied to surface and subsurface soils for metabolism studies. After 60 d of incubation, mineralization of deethylatrazine to {sup 14}CO{sub 2} in the atrazine-history surface soil was twice that in the no-history surface soils (34% and 17% of the applied {sup 14}C, respectively). In surface soils, 25% of the applied {sup 14}C remained as deethylatrazine in the atrazine-history soil, compared with 35% in the no-history soil. Microbial plate counts indicated an increase in numbers of bacteria and fungi in soils incubated with deethylatrazine compared to control soils. Total microbial biomass of soils incubated with deethylatrazine, as determined by CO{sub 2} efflux using an infrared (IR) gas analyzer, showed no significant difference between atrazine-history, and no-history soil, but did show an increase above untreated control soils. Prior to treating soils with deethylatrazine, specific deethylatrazine degraders were quantified using a {sup 14}C-most-probable-number procedure. Deethylatrazine degraders were more numerous in atrazine-history surface soil compared to no-history surface soil. After incubation of soils with deethylatrazine, deethylatrazine degraders were more numerous in both history soils as compared to control soils. From these studies, it appears that deethylatrazine is degraded microbially to a greater extent in soils that have had long-term exposure to atrazine at field application rates compared to soils with no long-term exposure. Decreased persistence of this major metabolite of atrazine in atrazine-history soils is important in that there will be less available for movement in surface runoff and to groundwater.

  13. Hydroxylamine Promoted Goethite Surface Fenton Degradation of Organic Pollutants.

    PubMed

    Hou, Xiaojing; Huang, Xiaopeng; Jia, Falong; Ai, Zhihui; Zhao, Jincai; Zhang, Lizhi

    2017-03-30

    In this study, we construct a surface Fenton system with hydroxylamine (NH2OH), goethite (α-FeOOH), and H2O2 (α-FeOOH-HA/H2O2) to degrade various organic pollutants including dyes (methyl orange, methylene blue, and rhodamine B), pesticides (pentachlorophenol, alachlor, and atrazine), and antibiotics (tetracycline, chloramphenicol, and lincomycin) at pH 5.0. In this surface Fenton system, the presence of NH2OH could greatly promote the H2O2 decomposition on the α-FeOOH surface to produce •OH without releasing any detectable iron ions during the alachlor degradation, which was different from some previously reported heterogeneous Fenton counterparts. Moreover, the •OH generation rate constant of this surface Fenton system was 102 - 104 times those of previous heterogeneous Fenton processes. The interaction between α-FeOOH and NH2OH was investigated with using attenuated total reflectance Fourier transform infrared spectroscopy and density functional theory calculations. The effective degradation of organic pollutants in this surface Fenton system was ascribed to the efficient Fe(III)/Fe(II) cycle on the α-FeOOH surface promoted by NH2OH, which was confirmed by X-ray photoelectron spectroscopy analysis. The degradation intermediates and mineralization of alachlor in this surface Fenton system were then systematically investigated using total organic carbon and ion chromatography, liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. This study offers a new strategy to degrade organic pollutants, and also sheds light on the environmental effects of goethite.

  14. Degradation of plant cuticles in soils: impact on formation and sorptive ability of humin-mineral matrices.

    PubMed

    Olshansky, Yaniv; Polubesova, Tamara; Chefetz, Benny

    2015-05-01

    Plant cuticles are important precursors for soil organic matter, in particular for soil humin, which is considered an efficient sorbent for organic pollutants. In this study, we examined degradation and transformation of cuticles isolated from fruit and leaves in loamy sand and sandy clay loessial arid brown soils. We then studied sorption of phenanthrene and carbamazepine to humin-mineral matrices isolated from the incubated soils. Low degradation (22%) was observed for agave cuticle in a sandy clay soil system, whereas high degradation (68-78%) was obtained for agave cuticle in a loamy sand soil system and for loamy sand and sandy clay soils amended with tomato cuticle. During incubation, most of the residual organic matter was accumulated in the humin fraction. Sorption of phenanthrene was significantly higher for humin-mineral matrices obtained from soils incubated with plant cuticles as compared with soils without cuticle application. Sorption of carbamazepine to humin-mineral matrices was not affected by cuticle residues. Cooperative sorption of carbamazepine on humin-mineral matrices isolated from sandy clay soil is suggested. Sorption-desorption hysteresis of both phenanthrene and carbamazepine was lower for humin-mineral matrices obtained from soils incubated with plant cuticles as compared with nonamended soils. Our results show that cuticle composition significantly affects the rate and extent of cuticle degradation in soils and that plant cuticle application influences sorption and desorption of polar and nonpolar pollutants by humin-mineral matrices.

  15. Degradation of fuel oil in salt marsh soils affected by the Prestige oil spill.

    PubMed

    Vega, Flora A; Covelo, Emma F; Reigosa, Manuel J; Andrade, María Luisa

    2009-07-30

    We assessed natural degradation of fuel oil in three marshes from Galicia (Spain) affected by the Prestige oil spill (Baldaio, Barizo, and Muxía). Soil samples collected from polluted and unpolluted areas on four different dates were used to determine total petroleum hydrocarbon content and fuel-oil components. Natural degradation was monitored by analysing changes in the proportion of saturated hydrocarbons, aromatics, asphaltenes and resins in the soils, and also by evaluating the degree of depletion of saturated hydrocarbons on each sampling date. We additionally assessed the phytoremediation potential of Lolium perenne, L., Convolvulus arvensis L. and Raphanus raphanistrum L. All marsh soils exhibited natural degradation of saturated and aromatic hydrocarbons to between 85 and 95% in most cases. In contrast, asphaltenes and resins were degraded to a lesser extent (viz. 64-76% in Barizo 1, Muxía and Traba; 39-44% in Baldaio; and only 12% in Barizo 2, where flooding by the river continues to introduce balls of fuel oil into the soil). Monitoring analyses revealed natural degradation to be dependent on the thickness of the pollutant layer. Field plots sown with L. perenne L. exhibited no significant differences in fuel-oil degradation from untreated plots.

  16. Plant enhanced degradation of phenanthrene in the contaminated soil.

    PubMed

    Liao, Min; Xie, Xiao-Mei

    2006-01-01

    The degradative characteristics of phenanthrene, microbial biomass carbon, plate counts of heterotrophic bacteria and most probable number (MPN) of phenanthrene degraders in non-rhizosphere or rhizosphere soils with uninoculating or inoculating phenanthrene degraders were measured. At the initial concentration of 20 mg phenanthrene/kg soil, the half-lives of phenanthrene in uninoculated non-rhizosphere soil, uninoculated rhizosphere soil, inoculated non-rhizosphere soil, and inoculated rhizosphere soil were measured to be 81.5, 47.8, 15.1 and 6.4 d, respectively, and corresponding kinetic data fitted first-order kinetics. The highest degradation rate of phenanthrene was observed in inoculated rhizosphere soil. The degradative characteristics of phenanthrene were closely related to the effects of vegetation on soil microbial process. Vegetation could enhance the magnitude of rhizosphere microbial communities, microbial biomass content, and heterotrophic bacterial community, but barely influence those community components responsible for phenanthrene degradation. Results suggested that combination of vegetation and inoculation with degrading microorganisms of target organic contaminants was a better pathway to enhance degradation of the organic contaminants in soil.

  17. Air pollutants degrade floral scents and increase insect foraging times

    NASA Astrophysics Data System (ADS)

    Fuentes, Jose D.; Chamecki, Marcelo; Roulston, T.'ai; Chen, Bicheng; Pratt, Kenneth R.

    2016-09-01

    Flowers emit mixtures of scents that mediate plant-insect interactions such as attracting insect pollinators. Because of their volatile nature, however, floral scents readily react with ozone, nitrate radical, and hydroxyl radical. The result of such reactions is the degradation and the chemical modification of scent plumes downwind of floral sources. Large Eddy Simulations (LES) are developed to investigate dispersion and chemical degradation and modification of floral scents due to reactions with ozone, hydroxyl radical, and nitrate radical within the atmospheric surface layer. Impacts on foraging insects are investigated by utilizing a random walk model to simulate insect search behavior. Results indicate that even moderate air pollutant levels (e.g., ozone mixing ratios greater than 60 parts per billion on a per volume basis, ppbv) substantially degrade floral volatiles and alter the chemical composition of released floral scents. As a result, insect success rates of locating plumes of floral scents were reduced and foraging times increased in polluted air masses due to considerable degradation and changes in the composition of floral scents. Results also indicate that plant-pollinator interactions could be sensitive to changes in floral scent composition, especially if insects are unable to adapt to the modified scentscape. The increase in foraging time could have severe cascading and pernicious impacts on the fitness of foraging insects by reducing the time devoted to other necessary tasks.

  18. Soil organic matter degradability in four Japanese forest soils

    NASA Astrophysics Data System (ADS)

    Moriya, K.; Koarashi, J.; Atarashi-Andoh, M.; Moriizumi, J.; Yamazawa, H.; Ishizuka, S.

    2011-12-01

    Soil organic carbon (SOC) is the largest carbon reservoir in terrestrial ecosystems, and CO2 emission derived from SOC decomposition is considered to strongly influence atmospheric CO2 concentration. Therefore, it is important to understand what factors control the process of SOC decomposition. We studied the temperature sensitivity of SOC decomposition in forest surface soils by an incubation experiment at two temperatures. Soil samples were collected from the top 20 cm of mineral soils at four forest sites in Japan: AP (Appi: 40°00'N, 140°56'E), US (Ushiku: 35°57'N, 140°10'E), OG (Ogawa: 36°56'N, 140°35'E), and HO (Hitsujigaoka: 43°59'N, 141°23'E). The soil samples were sieved with a 4 mm-mesh and remaining roots in the samples were carefully removed by hand. Approximately a 75 g dry weight equivalent of the sample was adjusted to 50% of water holding capacity and put into a 1 L jar. Triplicate jars were enclosed after flushing their headspaces with CO2-free air and incubated at temperatures of 10°C and 20°C, respectively. We periodically collected 1 mL of headspace gas from the jars to measure CO2 concentration using a gas chromatograph. When the CO2 concentration in each jar reached 1.5% in volume, the headspace gas in the jar was collected to measure carbon isotope ratio of the CO2, and then the headspace of the jar was re-flushed and continued to incubate. The SOC decomposition rate at 20°C was consistently higher than that at 10°C, the order of which was AP ≤ US ≤ OG < HO. This order did not correspond to the orders of both mean annual temperature at the sites (AP < HO < OG < US), and total organic carbon content per dry soil weight (HO < US < AP < OG). Our result suggests that field temperature does not exert predominant control over SOC degradability in Japanese forest surface soils. Q10 values obtained for the AP, US, and OG soils was initially approximately 3 and increased up to 4 after one month of incubation. The increase in Q10 value

  19. Bioremediation of crude oil polluted soil by the white rot fungus, Pleurotus tuberregium (Fr.) Sing.

    PubMed

    Isikhuemhen, Omoanghe S; Anoliefo, Geoffrey O; Oghale, Okelezo I

    2003-01-01

    Bioremediation has become an attractive alternative to physicochemical methods of remediation of polluted sites. White rot fungi (WRF) are increasingly being investigated and used in bioremediation, because of their ability to degrade an extremely diverse range of very persistent or toxic environmental pollutants. The white rot fungus, Pleurotus tuberregium, was examined for its ability to ameliorate crude oil polluted soil. This was inferred from the ability of the polluted soil to support seed germination and seedling growth in Vigna unguiculata, at 0, 7 and 14 days post treatment. Results obtained from the present study showed that bioremediation of soil contaminated with crude oil was possible, especially when the fungus had been allowed to establish and fully colonize the substrate mixed with the soil. There were significant improvements in % germination, plant height and root elongation values of test plants, when seeds were planted 14 days post soil treatment. At 1 to 5% crude oil pollution, % germination values were comparable with the values in control plants in the 14 days treatment, and significantly higher than values obtained in the day 0 treatment. Also, at the highest level of crude oil pollution (15%), there was about 25% improvement in % germination value over the 0 day treatment. This trend of improvement in values was also observed for plant height, root elongation and biomass accumulation as well as decreased total hydrocarbon content.

  20. Pyrethroid-Degrading Microorganisms and Their Potential for the Bioremediation of Contaminated Soils: A Review.

    PubMed

    Cycoń, Mariusz; Piotrowska-Seget, Zofia

    2016-01-01

    Pyrethroid insecticides have been used to control pests in agriculture, forestry, horticulture, public health and for indoor home use for more than 20 years. Because pyrethroids were considered to be a safer alternative to organophosphate pesticides (OPs), their applications significantly increased when the use of OPs was banned or limited. Although, pyrethroids have agricultural benefits, their widespread and continuous use is a major problem as they pollute the terrestrial and aquatic environments and affect non-target organisms. Since pyrethroids are not degraded immediately after application and because their residues are detected in soils, there is an urgent need to remediate pyrethroid-polluted environments. Various remediation technologies have been developed for this purpose; however, bioremediation, which involves bioaugmentation and/or biostimulation and is a cost-effective and eco-friendly approach, has emerged as the most advantageous method for cleaning-up pesticide-contaminated soils. This review presents an overview of the microorganisms that have been isolated from pyrethroid-polluted sites, characterized and applied for the degradation of pyrethroids in liquid and soil media. The paper is focused on the microbial degradation of the pyrethroids that have been most commonly used for many years such as allethrin, bifenthrin, cyfluthrin, cyhalothrin, cypermethrin, deltamethrin, fenpropathrin, fenvalerate, and permethrin. Special attention is given to the bacterial strains from the genera Achromobacter, Acidomonas, Bacillus, Brevibacterium, Catellibacterium, Clostridium, Lysinibacillus, Micrococcus, Ochrobactrum, Pseudomonas, Serratia, Sphingobium, Streptomyces, and the fungal strains from the genera Aspergillus, Candida, Cladosporium, and Trichoderma, which are characterized by their ability to degrade various pyrethroids. Moreover, the current knowledge on the degradation pathways of pyrethroids, the enzymes that are involved in the cleavage of

  1. Pyrethroid-Degrading Microorganisms and Their Potential for the Bioremediation of Contaminated Soils: A Review

    PubMed Central

    Cycoń, Mariusz; Piotrowska-Seget, Zofia

    2016-01-01

    Pyrethroid insecticides have been used to control pests in agriculture, forestry, horticulture, public health and for indoor home use for more than 20 years. Because pyrethroids were considered to be a safer alternative to organophosphate pesticides (OPs), their applications significantly increased when the use of OPs was banned or limited. Although, pyrethroids have agricultural benefits, their widespread and continuous use is a major problem as they pollute the terrestrial and aquatic environments and affect non-target organisms. Since pyrethroids are not degraded immediately after application and because their residues are detected in soils, there is an urgent need to remediate pyrethroid-polluted environments. Various remediation technologies have been developed for this purpose; however, bioremediation, which involves bioaugmentation and/or biostimulation and is a cost-effective and eco-friendly approach, has emerged as the most advantageous method for cleaning-up pesticide-contaminated soils. This review presents an overview of the microorganisms that have been isolated from pyrethroid-polluted sites, characterized and applied for the degradation of pyrethroids in liquid and soil media. The paper is focused on the microbial degradation of the pyrethroids that have been most commonly used for many years such as allethrin, bifenthrin, cyfluthrin, cyhalothrin, cypermethrin, deltamethrin, fenpropathrin, fenvalerate, and permethrin. Special attention is given to the bacterial strains from the genera Achromobacter, Acidomonas, Bacillus, Brevibacterium, Catellibacterium, Clostridium, Lysinibacillus, Micrococcus, Ochrobactrum, Pseudomonas, Serratia, Sphingobium, Streptomyces, and the fungal strains from the genera Aspergillus, Candida, Cladosporium, and Trichoderma, which are characterized by their ability to degrade various pyrethroids. Moreover, the current knowledge on the degradation pathways of pyrethroids, the enzymes that are involved in the cleavage of

  2. Effect of biochar or activated carbon amendment on the volatilisation and biodegradation of organic soil pollutants

    NASA Astrophysics Data System (ADS)

    Werner, David; Meynet, Paola; Bushnaf, Khaled

    2013-04-01

    Biochar or activated carbon added to contaminated soil may temporarily reduce the volatilisation of organic pollutants by enhanced sorption. The long-term effect of sorbent amendments on the fate of volatile petroleum hydrocarbon mixtures (VPHs) will depend on the responses of the soil bacterial community members, especially those which may utilize VPHs as carbon substrates. We investigated the volatilisation and biodegradation of VPHs emanating from NAPL sources and migrating through one meter long columns containing unsaturated sandy soil with and without 2% biochar or activated carbon amendment. After 420 days, VPH volatilisation from AC amended soil was less than 10 percent of the cumulative VPH volatilisation flux from unamended soil. The cumulative CO2 volatilisation flux increased more slowly in AC amended soil, but was comparable to the untreated soil after 420 days. This indicated that the pollution attenuation over a 1 meter distance was improved by the AC amendment. Biochar was a weaker VPH sorbent than AC and had a lesser effect on the cumulative VPH and CO2 fluxes. We also investgated the predominant bacterial community responses in sandy soil to biochar and/or VPH addition with a factorially designed batch study, and by analyzing preserved soil samples. Biochar addition alone had only weak effects on soil bacterial communities, while VPH addition was a strong community structure shaping factor. The bacterial community effects of biochar-enhanced VPH sorption were moderated by the limited biomass carrying capacity of the sandy soil investigated which contained only low amounts of inorganic nitrogen. Several Pseudomonas spp., including Pseudomonas putida strains, became dominant in VPH polluted soil with and without biochar. The ability of these versatile VPH degraders to effectively regulate their metabolic pathways according to substrate availabilities may additionally have moderated bacterial community structure responses to the presence of biochar

  3. Degradation of Tibetan grasslands: Consequences for soil organic carbon and nutrients losses

    NASA Astrophysics Data System (ADS)

    Liu, Shibin; Schleuss, Per-Marten; Kuzyakov, Yakov

    2017-04-01

    estimations regarding SOC and nutrients losses across the whole ecosystem. This highly matters because large amounts of SOC have been lost due to erosion and mineralization. Most likely this has polluted the Tibetan headwaters and contributed to climate change, respectively. Further, the decreasing N and P losses have reduced soil fertility lowering forage production. Therefore, it endangers the livelihood of the Tibetan herders, which highly rely on forage to feed their livestock. Despite plenty of ameliorations (e.g. fertilization, grazing enclosure, reseeding) have been proposed and implemented at many locations, their impacts on pasture ecosystems (especially on soil fertility) are still subtle and thus require further investigations. Keywords: Kobresia pastures, Tibetan Plateau, Grassland degradation, Soil organic carbon, Soil nutrients

  4. Phytoremediation of petroleum-polluted soils: application of Polygonum aviculare and its root-associated (penetrated) fungal strains for bioremediation of petroleum-polluted soils.

    PubMed

    Mohsenzadeh, Fariba; Nasseri, Simin; Mesdaghinia, Alireza; Nabizadeh, Ramin; Zafari, Doustmorad; Khodakaramian, Gholam; Chehregani, Abdolkarim

    2010-05-01

    Petroleum-polluted soils are a common disaster in many countries. Bioremediation of oil contamination in soils is based on the stimulation of petroleum-hydrocarbon-degrading fungal and microbial communities. A field study was conducted in a petroleum-contaminated site to find petroleum-resistant plants and their root-associated fungal strains for use in bioremediation of petroleum-polluted soils. Results and observations showed that the amounts of petroleum pollution in nonvegetated soils were several times higher than in vegetated soils. Plants collected from petroleum-polluted areas were identified using morphological characters. Results indicated that seven plant species were growing on the contaminated sites: Alhaji cameleron L. (Fabaceae), Amaranthus retroflexus L. var. retroflexus (Amaranthaceae), Convolvulus arvensis L. (Convolvulaceae), Chrozophora hierosolymitana Spreg. (Euphorbiaceae), Noea mucronata L. (Boraginaceae), Poa sp. (Poaceae), and Polygonum aviculare L. (Polygonaceae). The root-associated fungi of each plant were determined and results showed the presence of 11 species that associated with and also penetrated the roots of plants growing in the polluted areas. Altenaria sp. was common to all of the plants and the others had species-specific distribution within the plants. The largest numbers of fungal species (six) were determined for P. aviculare and Poa sp. in polluted areas. However, the variation of fungal strains in the plants collected from petroleum-polluted areas was greater than for nonpolluted ones. Culture of fungi in oil-contaminated media showed that all the studied fungi were resistant to low petroleum pollution (1% v/v) and a few species, especially Fusarium species, showed resistance to higher petroleum pollution (10% v/v) and may be suitable for bioremediation in highly polluted areas. Bioremediation tests with P. aviculare, with and without fungal strains, showed that application of both the plant and its root-associated fungal

  5. Soil macroinvertebrates as indicators of pollution by heavy metals.

    PubMed

    Nahmani, Johanne; Rossi, Jean-Pierre

    2003-03-01

    A broad range of soil pollutants were found to decrease with distance from a zinc smelter from 35,000 to 77, 8270 to 40 and from 190 to less than 1 ppm for zinc, lead and cadmium, respectively. Along this gradient, observed species richness of soil macro-organisms seemed to be more affected by the land-use type than by soil pollution--minimum in crops (21), maximum in woody sites (126). IndVal index allowed isolation of 21 indicator species from the 339 morphospecies identified. Most of these indicator species were characteristic of the unpolluted sites: only two diplopods and one gastropod from polluted poplar plantations, and none from the most polluted site. Since soil invertebrates respond to different environmental factors, including direct effect of heavy metals, we suggest there may be some confounding factors generating spurious relationships between the values of species as bioindicators and the pollution status they are supposed to indicate.

  6. Remote assessment of the degree of soil degradation from radiation properties of soils

    NASA Astrophysics Data System (ADS)

    Romanov, A. N.

    2009-03-01

    The effect of the water and salt contents, the soil texture, and the groundwater level on the radiation properties of soils was studied. A methodology was developed for the remote assessment of the degree of soil degradation on the basis of measuring the brightness temperature and emissivity of soils in the microwave region. Criteria based on the remote measurements of radiation parameters of soils for recording changes in the water-physical and other properties of soils, which are necessary for detecting degradation processes at early stages, were substantiated. For the remote assessment of soil degradation, it was proposed to analyze trends in changes with time concerning the emissivities of unfrozen soils occurring at a positive temperature (depending on the soil water content and the groundwater level), the emissivities of frozen nonsaline soils (depending on the soil texture and thermodynamic temperature), and the brightness temperature (depending on the soil salinity and thermodynamic temperature).

  7. Enantioselective degradation of metalaxyl in soils: chiral preference changes with soil pH.

    PubMed

    Buerge, Ignaz I; Poiger, Thomas; Müller, Markus D; Buser, Hans-Rudolf

    2003-06-15

    Chiral pesticides are often degraded enantio-/stereoselectively in soils. Degradation is typically studied with one or a small number of soils so that it is not possible to extrapolate the findings on chiral preference to other soils. For this study, the fungicide metalaxyl was chosen as a "chiral probe" to investigate its enantioselective degradation in 20 different soils, selected primarily to cover a wide range of soil properties (e.g., acidic/alkaline, aerobic/ anaerobic) rather than to consider soils of agricultural importance. Racemic metalaxyl was incubated in these soils under laboratory conditions, and the degradation of the enantiomers as well as the enantioselective formation/ degradation of the primary major metabolite, metalaxyl acid, was followed over time, using enantioselective GC-MS after ethylation with diazoethane. In aerobic soils with pH > 5, the fungicidally active R-enantiomer was degraded faster than the S-enantiomer (k(R) > k(S)), leading to residues with a composition [S] > [R]. However, in aerobic soils with pH 4-5, both enantiomers were degraded at similar rates (k(R) approximately k(S)), and in aerobic soils with pH < 4 and in most anaerobic soils, the enantioselectivity was reversed (k(R) < k(S)). These considerable soil-to-soil variations were observed with soils from locations close to each other, in one case even within a single soil profile. Liming and acidification of a "nonenantioselective" soil prior to incubation resulted in enantioselective degradation with k(R)> k(S) and k(R) < k(S), respectively. While the enantioselectivity (expressed as ES = (k(R) - k(S))/(k(R) + k(S))) of metalaxyl degradation in aerobic soils apparently correlated with soil pH, no such correlation was found for metalaxyl acid. Reevaluation of published kinetic data for the herbicides dichlorprop and mecoprop indicated similar correlations between soil pH and ES as for metalaxyl.

  8. Isothermal titration calorimetry - a new method for the quantification of microbial degradation of trace pollutants.

    PubMed

    Mariana, F; Buchholz, F; Harms, H; Yong, Z; Yao, J; Maskow, T

    2010-07-01

    The environmental fate and, in particular, biodegradation rates of hydrophobic organic compounds (HOC) are of high interest due to the ubiquity, persistence, and potential health effects of these compounds. HOC tend to interact with bioreactor materials and sampling devices and are frequently volatile, so that conventionally derived degradation parameters are often biased. We report on the development and validation of a novel calorimetric approach that serves to gain real time information on the kinetics and the physiology of HOC bioconversion in aqueous systems while overcoming weaknesses of conventional biodegradation experiments. Soil bacteria Mycobacterium frederiksbergense LB501T, Rhodococcus erythropolis K2-3 and Pseudomonas putida G7 were exposed to pulsed titrations of dissolved anthracene, 4-(2,4-dichlorophenoxy)butyric acid or naphthalene, respectively, and the thermal responses were monitored. The combinations of strains and pollutants were selected as examples for complete and partial biodegradation and complete degradation with storage product formation, respectively. Heat production signals were interpreted thermodynamically and in terms of Michaelis-Menten kinetics. The half-saturation constant k(D) and the degradation rate r(D)(Max) were derived. Comparison with conventional methods shows the suitability to extract kinetic degradation parameters of organic trace pollutants from simple ITC experiments, while thermodynamic interpretation provided further information about the metabolic fate of HOC compounds.

  9. Fungal communities associated with degradation of polyester polyurethane in soil.

    PubMed

    Cosgrove, Lee; McGeechan, Paula L; Robson, Geoff D; Handley, Pauline S

    2007-09-01

    Soil fungal communities involved in the biodegradation of polyester polyurethane (PU) were investigated. PU coupons were buried in two sandy loam soils with different levels of organic carbon: one was acidic (pH 5.5), and the other was more neutral (pH 6.7). After 5 months of burial, the fungal communities on the surface of the PU were compared with the native soil communities using culture-based and molecular techniques. Putative PU-degrading fungi were common in both soils, as <45% of the fungal colonies cleared the colloidal PU dispersion Impranil on solid medium. Denaturing gradient gel electrophoresis showed that fungal communities on the PU were less diverse than in the soil, and only a few species in the PU communities were detectable in the soil, indicating that only a small subset of the soil fungal communities colonized the PU. Soil type influenced the composition of the PU fungal communities. Geomyces pannorum and a Phoma sp. were the dominant species recovered by culturing from the PU buried in the acidic and neutral soils, respectively. Both fungi degraded Impranil and represented >80% of cultivable colonies from each plastic. However, PU was highly susceptible to degradation in both soils, losing up to 95% of its tensile strength. Therefore, different fungi are associated with PU degradation in different soils but the physical process is independent of soil type.

  10. Carbaryl degradation by bacterial isolates from a soil ecosystem of the Gaza Strip.

    PubMed

    Hamada, Mazen; Matar, Ammar; Bashir, Abdallah

    2015-01-01

    Carbaryl is an important and widely used insecticide that pollutes soil and water systems. Bacteria from the local soil ecosystem of the Gaza Strip capable of utilizing carbaryl as the sole source of carbon and nitrogen were isolated and identified as belonging to Bacillus, Morganella, Pseudomonas, Aeromonas and Corynebacterium genera. Carbaryl biodegradation by Bacillus, Morganella and Corynebacterium isolates was analyzed in minimal liquid media supplemented with carbaryl as the only source of carbon and nitrogen. Bacillus and Morganella exhibited 94.6% and 87.3% carbaryl degradation, respectively, while Corynebacterium showed only moderate carbaryl degradation at 48.8%. These results indicate that bacterial isolates from a local soil ecosystem in the Gaza Strip are able to degrade carbaryl and can be used to decrease the risk of environmental contamination by this insecticide.

  11. Carbaryl degradation by bacterial isolates from a soil ecosystem of the Gaza Strip

    PubMed Central

    Hamada, Mazen; Matar, Ammar; Bashir, Abdallah

    2015-01-01

    Abstract Carbaryl is an important and widely used insecticide that pollutes soil and water systems. Bacteria from the local soil ecosystem of the Gaza Strip capable of utilizing carbaryl as the sole source of carbon and nitrogen were isolated and identified as belonging to Bacillus, Morganella, Pseudomonas, Aeromonas and Corynebacterium genera. Carbaryl biodegradation by Bacillus, Morganella and Corynebacterium isolates was analyzed in minimal liquid media supplemented with carbaryl as the only source of carbon and nitrogen. Bacillus and Morganella exhibited 94.6% and 87.3% carbaryl degradation, respectively, while Corynebacterium showed only moderate carbaryl degradation at 48.8%. These results indicate that bacterial isolates from a local soil ecosystem in the Gaza Strip are able to degrade carbaryl and can be used to decrease the risk of environmental contamination by this insecticide. PMID:26691466

  12. Bioremediation trial on aged PCB-polluted soils--a bench study in Iceland.

    PubMed

    Lehtinen, Taru; Mikkonen, Anu; Sigfusson, Bergur; Ólafsdóttir, Kristín; Ragnarsdóttir, Kristín Vala; Guicharnaud, Rannveig

    2014-02-01

    Polychlorinated biphenyls (PCBs) pose a threat to the environment due to their high adsorption capacity to soil organic matter, stability and low reactivity, low water solubility, toxicity and ability to bioaccumulate. With Icelandic soils, research on contamination issues has been very limited and no data has been reported either on PCB degradation potential or rate. The goals of this research were to assess the bioavailability of aged PCBs in the soils of the old North Atlantic Treaty Organization facility in Keflavík, Iceland and to find the best biostimulation method to decrease the pollution. The effectiveness of different biostimulation additives (N fertiliser, white clover and pine needles) at different temperatures (10 and 30 °C) and oxygen levels (aerobic and anaerobic) were tested. PCB bioavailability to soil fauna was assessed with earthworms (Eisenia foetida). PCBs were bioavailable to earthworms (bioaccumulation factor 0.89 and 0.82 for earthworms in 12.5 ppm PCB soil and in 25 ppm PCB soil, respectively), with less chlorinated congeners showing higher bioaccumulation factors than highly chlorinated congeners. Biostimulation with pine needles at 10 °C under aerobic conditions resulted in nearly 38 % degradation of total PCBs after 2 months of incubation. Detection of the aerobic PCB degrading bphA gene supports the indigenous capability of the soils to aerobically degrade PCBs. Further research on field scale biostimulation trials with pine needles in cold environments is recommended in order to optimise the method for onsite remediation.

  13. Detection of explosives and their degradation products in soil environments.

    PubMed

    Halasz, A; Groom, C; Zhou, E; Paquet, L; Beaulieu, C; Deschamps, S; Corriveau, A; Thiboutot, S; Ampleman, G; Dubois, C; Hawari, Jalal

    2002-07-19

    Polynitro organic explosives [hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and 2,4,6-trinitrotoluene (TNT)] are typical labile environmental pollutants that can biotransform with soil indigenous microorganisms, photodegrade by sunlight and migrate through subsurface soil to cause groundwater contamination. To be able to determine the type and concentration of explosives and their (bio)transformation products in different soil environments, a comprehensive analytical methodology of sample preparation, separation and detection is thus required. The present paper describes the use of supercritical carbon dioxide (SC-CO2), acetonitrile (MeCN) (US Environmental Protection Agency Method 8330) and solid-phase microextraction (SPME) for the extraction of explosives and their degradation products from various water, soil and plant tissue samples for subsequent analysis by either HPLC-UV, capillary electrophoresis (CE-UV) or GC-MS. Contaminated surface and subsurface soil and groundwater were collected from either a TNT manufacturing facility or an anti-tank firing range. Plant tissue samples were taken fromplants grown in anti-tank firing range soil in a greenhouse experiment. All tested soil and groundwater samples from the former TNT manufacturing plant were found to contain TNT and some of its amino reduced and partially denitrated products. Their concentrations as determined by SPME-GC-MS and LC-UV depended on the location of sampling at the site. In the case of plant tissues, SC-CO2 extraction followed by CE-UV analysis showed only the presence of HMX. The concentrations of HMX (<200 mg/kg) as determined by supercritical fluid extraction (SC-CO2)-CE-UV were comparable to those obtained by MeCN extraction, although the latter technique was found to be more efficient at higher concentrations (>300 mg/kg). Modifiers such as MeCN and water enhanced the SC-CO2 extractability of HMX from plant tissues.

  14. Bioremediation of bisphenol-A polluted soil by Sphingomonas bisphenolicum AO1 and the microbial community existing in the soil.

    PubMed

    Matsumura, Yoshinobu; Akahira-Moriya, Ayako; Sasaki-Mori, Miho

    2015-01-01

    Bisphenol A (BPA, 2,2'-Bis (4-hydroxyphenyl) propane) is an artificial pollutant that is easily detected in soil and water environments. BPA decomposition and removal from the environment is relatively difficult due to its stability. This study evaluated the BPA decomposition and removal activities of the microbial community existing in the soil with or without Sphingomonas bisphenolicum AO1, and revealed the toxic effects of BPA towards the microbial community. The microbial community in soil was able to degrade BPA at 1.0 mg·g(-1) soil or lower, although its degradation was slow. On the other hand, BPA at more than 10 mg·g(-1) soil was not only degraded by the microbial community but also decreased its diversity, suggesting that BPA is harmful to many microorganisms. PCR-TTGE analysis and the cloned 16S rRNA gene sequence analysis indicated that Sphingomonadales, Xanthomonadales, Burkholderiales and Pseudomonadales in the microbial community might independently or cooperatively degrade BPA. On the other hand, supplementation with strain AO1 was able to significantly improve the BPA decomposition activity of the microbial community in soil even at 10 mg BPA·g(-1) soil, although BPA at 100 mg·g(-1) soil overwhelmed the BPA decomposition activity of strain AO1. Furthermore, it was also concluded that strain AO1 could not inhabit BPA purified soil after decomposition of BPA by strain AO1 and the soil microbial community, suggesting that the application of strain AO1 could be a low-burden method for the decomposition and removal of BPA from the natural environment.

  15. Impact of Metal Pollution and Thlaspi caerulescens Growth on Soil Microbial Communities▿

    PubMed Central

    Epelde, Lur; Becerril, José M.; Kowalchuk, George A.; Deng, Ye; Zhou, Jizhong; Garbisu, Carlos

    2010-01-01

    Soil microorganisms drive critical functions in plant-soil systems. As such, various microbial properties have been proposed as indicators of soil functioning, making them potentially useful in evaluating the recovery of polluted soils via phytoremediation strategies. To evaluate microbial responses to metal phytoextraction using hyperaccumulators, a microcosm experiment was carried out to study the impacts of Zn and/or Cd pollution and Thlaspi caerulescens growth on key soil microbial properties: basal respiration; substrate-induced respiration (SIR); bacterial community structure as assessed by PCR-denaturing gradient gel electrophoresis (DGGE); community sizes of total bacteria, ammonia-oxidizing bacteria, and chitin-degrading bacteria as assessed by quantitative PCR (Q-PCR); and functional gene distributions as determined by functional gene arrays (GeoChip). T. caerulescens proved to be suitable for Zn and Cd phytoextraction: shoots accumulated up to 8,211 and 1,763 mg kg−1 (dry weight [DW]) of Zn and Cd, respectively. In general, Zn pollution led to decreased levels of basal respiration and ammonia-oxidizing bacteria, while T. caerulescens growth increased the values of substrate-induced respiration (SIR) and total bacteria. In soils polluted with 1,000 mg Zn kg−1 and 250 mg Cd kg−1 (DW), soil bacterial community profiles and the distribution of microbial functional genes were most affected by the presence of metals. Metal-polluted and planted soils had the highest percentage of unique genes detected via the GeoChip (35%). It was possible to track microbial responses to planting with T. caerulescens and to gain insight into the effects of metal pollution on soilborne microbial communities. PMID:20935131

  16. Impact of metal pollution and Thlaspi caerulescens growth on soil microbial communities.

    PubMed

    Epelde, Lur; Becerril, José M; Kowalchuk, George A; Deng, Ye; Zhou, Jizhong; Garbisu, Carlos

    2010-12-01

    Soil microorganisms drive critical functions in plant-soil systems. As such, various microbial properties have been proposed as indicators of soil functioning, making them potentially useful in evaluating the recovery of polluted soils via phytoremediation strategies. To evaluate microbial responses to metal phytoextraction using hyperaccumulators, a microcosm experiment was carried out to study the impacts of Zn and/or Cd pollution and Thlaspi caerulescens growth on key soil microbial properties: basal respiration; substrate-induced respiration (SIR); bacterial community structure as assessed by PCR-denaturing gradient gel electrophoresis (DGGE); community sizes of total bacteria, ammonia-oxidizing bacteria, and chitin-degrading bacteria as assessed by quantitative PCR (Q-PCR); and functional gene distributions as determined by functional gene arrays (GeoChip). T. caerulescens proved to be suitable for Zn and Cd phytoextraction: shoots accumulated up to 8,211 and 1,763 mg kg(-1) (dry weight [DW]) of Zn and Cd, respectively. In general, Zn pollution led to decreased levels of basal respiration and ammonia-oxidizing bacteria, while T. caerulescens growth increased the values of substrate-induced respiration (SIR) and total bacteria. In soils polluted with 1,000 mg Zn kg(-1) and 250 mg Cd kg(-1) (DW), soil bacterial community profiles and the distribution of microbial functional genes were most affected by the presence of metals. Metal-polluted and planted soils had the highest percentage of unique genes detected via the GeoChip (35%). It was possible to track microbial responses to planting with T. caerulescens and to gain insight into the effects of metal pollution on soilborne microbial communities.

  17. TREATMENT OF A PENTACHLOROPHENOL AND CREOSOTE-CONTAMINATED SOIL USING THE LIGNIN-DEGRADING FUNGUS PHANERO- CHAETE SORDIDA: A FIELD DEMONSTRATION

    EPA Science Inventory

    The feasibility of large-scale fungal bioaugmentation was evaluated by assessing the ability of the lignin-degrading fungus Phanerochaete sordida to decrease the soil concentrations of pentachlorophenol (PCP) and 13 priority pollutant polynuclear aromatic (PNA) creosote component...

  18. TREATMENT OF A PENTACHLOROPHENOL AND CREOSOTE-CONTAMINATED SOIL USING THE LIGNIN-DEGRADING FUNGUS PHANERO- CHAETE SORDIDA: A FIELD DEMONSTRATION

    EPA Science Inventory

    The feasibility of large-scale fungal bioaugmentation was evaluated by assessing the ability of the lignin-degrading fungus Phanerochaete sordida to decrease the soil concentrations of pentachlorophenol (PCP) and 13 priority pollutant polynuclear aromatic (PNA) creosote component...

  19. Nitroglycerin degradation mediated by soil organic carbon under aerobic conditions.

    PubMed

    Bordeleau, Geneviève; Martel, Richard; Bamba, Abraham N'Valoua; Blais, Jean-François; Ampleman, Guy; Thiboutot, Sonia

    2014-10-01

    The presence of nitroglycerin (NG) has been reported in shallow soils and pore water of several military training ranges. In this context, NG concentrations can be reduced through various natural attenuation processes, but these have not been thoroughly documented. This study aimed at investigating the role of soil organic matter (SOM) in the natural attenuation of NG, under aerobic conditions typical of shallow soils. The role of SOM in NG degradation has already been documented under anoxic conditions, and was attributed to SOM-mediated electron transfer involving different reducing agents. However, unsaturated soils are usually well-oxygenated, and it was not clear whether SOM could participate in NG degradation under these conditions. Our results from batch- and column-type experiments clearly demonstrate that in presence of dissolved organic matter (DOM) leached from a natural soil, partial NG degradation can be achieved. In presence of particulate organic matter (POM) from the same soil, complete NG degradation was achieved. Furthermore, POM caused rapid sorption of NG, which should result in NG retention in the organic matter-rich shallow horizons of the soil profile, thus promoting degradation. Based on degradation products, the reaction pathway appears to be reductive, in spite of the aerobic conditions. The relatively rapid reaction rates suggest that this process could significantly participate in the natural attenuation of NG, both on military training ranges and in contaminated soil at production facilities.

  20. Impact of electrochemical treatment of soil washing solution on PAH degradation efficiency and soil respirometry.

    PubMed

    Mousset, Emmanuel; Huguenot, David; van Hullebusch, Eric D; Oturan, Nihal; Guibaud, Gilles; Esposito, Giovanni; Oturan, Mehmet A

    2016-04-01

    The remediation of a genuinely PAH-contaminated soil was performed, for the first time, through a new and complete investigation, including PAH extraction followed by advanced oxidation treatment of the washing solution and its recirculation, and an analysis of the impact of the PAH extraction on soil respirometry. The study has been performed on the remediation of genuine PAH-contaminated soil, in the following three steps: (i) PAH extraction with soil washing (SW) techniques, (ii) PAH degradation with an electro-Fenton (EF) process, and (iii) recirculation of the partially oxidized effluent for another SW cycle. The following criteria were monitored during the successive washing cycles: PAH extraction efficiency, PAH oxidation rates and yields, extracting agent recovery, soil microbial activity, and pH of soil. Two representative extracting agents were compared: hydroxypropyl-beta-cyclodextrin (HPCD) and a non-ionic surfactant, Tween(®) 80. Six PAH with different numbers of rings were monitored: acenaphthene (ACE), phenanthrene (PHE), fluoranthene (FLA), pyrene (PYR), benzo(a)pyrene (BaP), and benzo(g,h,i)perylene (BghiP). Tween(®) 80 showed much better PAH extraction efficiency (after several SW cycles) than HPCD, regardless of the number of washing cycles. Based on successive SW experiments, a new mathematical relation taking into account the soil/water partition coefficient (Kd*) was established, and could predict the amount of each PAH extracted by the surfactant with a good correlation with experimental results (R(2) > 0.975). More HPCD was recovered (89%) than Tween(®) 80 (79%), while the monitored pollutants were completely degraded (>99%) after 4 h and 8 h, respectively. Even after being washed with partially oxidized solutions, the Tween(®) 80 solutions extracted significantly more PAH than HPCD and promoted better soil microbial activity, with higher oxygen consumption rates. Moreover, neither the oxidation by-products nor the acidic media (p

  1. Influence of low- and high-frequency heating on biodegrading microorganisms in soil: microbial degradation.

    PubMed

    Roland, Ulf; Holzer, Frank; Kopinke, Frank-Dieter

    2013-01-01

    The influence of low-frequency (50 Hz) resistive and high-frequency (13.56 MHz, radio-frequency) dielectric heating in comparison to conventional heating on the microbial degradation of pollutants in soil was studied. The investigation of the biodegradation of model substances (benzoic acid, acetic acid, glucose, sodium acetate) added to a standard soil showed no significant influence of the electrical heating methods when compared with samples heated to the same temperature in a water bath. Therefore, a hindrance of the microbial degradation could be excluded as it was done for soil respiration in a previous study. This finding is especially relevant for the application of these electrical heating methods for thermally enhanced soil bioremediation as an option for making in situ or ex situ clean-up processes more efficient.

  2. [Research advances in eco-toxicological diagnosis of soil pollution].

    PubMed

    Liu, Feng; Teng, Hong-Hui; Ren, Bai-Xiang; Shi, Shu-Yun

    2014-09-01

    Soil eco-toxicology provides a theoretical basis for ecological risk assessment of contaminated soils and soil pollution control. Research on eco-toxicological effects and molecular mechanisms of toxic substances in soil environment is the central content of the soil eco-toxicology. Eco-toxicological diagnosis not only gathers all the information of soil pollution, but also provides the overall toxic effects of soil. Therefore, research on the eco-toxicological diagnosis of soil pollution has important theoretical and practical significance. Based on the research of eco-toxicological diagnosis of soil pollution, this paper introduced some common toxicological methods and indicators, with the advantages and disadvantages of various methods discussed. However, conventional biomarkers can only indicate the class of stress, but fail to explain the molecular mechanism of damage or response happened. Biomarkers and molecular diagnostic techniques, which are used to evaluate toxicity of contaminated soil, can explore deeply detoxification mechanisms of organisms under exogenous stress. In this paper, these biomarkers and techniques were introduced systematically, and the future research trends were prospected.

  3. A review of soil heavy metal pollution from mines in China: pollution and health risk assessment.

    PubMed

    Li, Zhiyuan; Ma, Zongwei; van der Kuijp, Tsering Jan; Yuan, Zengwei; Huang, Lei

    2014-01-15

    Heavy metal pollution has pervaded many parts of the world, especially developing countries such as China. This review summarizes available data in the literature (2005-2012) on heavy metal polluted soils originating from mining areas in China. Based on these obtained data, this paper then evaluates the soil pollution levels of these collected mines and quantifies the risks these pollutants pose to human health. To assess these potential threat levels, the geoaccumulation index was applied, along with the US Environmental Protection Agency (USEPA) recommended method for health risk assessment. The results demonstrate not only the severity of heavy metal pollution from the examined mines, but also the high carcinogenic and non-carcinogenic risks that soil heavy metal pollution poses to the public, especially to children and those living in the vicinity of heavily polluted mining areas. In order to provide key management targets for relevant government agencies, based on the results of the pollution and health risk assessments, Cd, Pb, Cu, Zn, Hg, As, and Ni are selected as the priority control heavy metals; tungsten, manganese, lead-zinc, and antimony mines are selected as the priority control mine categories; and southern provinces and Liaoning province are selected as the priority control provinces. This review, therefore, provides a comprehensive assessment of soil heavy metal pollution derived from mines in China, while identifying policy recommendations for pollution mitigation and environmental management of these mines.

  4. Benzene degradation coupled with chlorate reduction in a soil column study.

    PubMed

    Tan, N C G; van Doesburg, W; Langenhoff, A A M; Stams, A J M

    2006-03-01

    Perchlorate and chlorate are electron acceptors that during reduction result in the formation of molecular oxygen. The produced oxygen can be used for activation of anaerobic persistent pollutants, like benzene. In this study chlorate was tested as potential electron acceptor to stimulate benzene degradation in anoxic polluted soil column. A chlorate amended benzene polluted soil column was operated over a period of 500 days. Benzene was immediately degraded in the column after start up, and benzene removal recovered completely after omission of chlorate or a too high influent chlorate concentration (22 mM). Mass balance calculations showed that per mole of benzene five mole of chlorate were reduced. At the end of the experiment higher loading rates were applied to measure the maximal benzene degradation rate in this system; a breakthrough of benzene was not observed. The average benzene degradation rate over this period was 31 micromol l(-1) h(-1) with a maximal of 78 micromol l(-1) h(-1). The high degradation rate and the necessity of chlorate indicate that oxygen produced during chlorate reduction indeed is used for the activation of benzene. This is the first column study where benzene biodegradation at a high rate coupled with anaerobic chlorate reduction is observed.

  5. Benefits of the Use of Sewage Sludge over EDTA to Remediate Soils Polluted with Heavy Metals.

    PubMed

    Hernández, Ana J; Gutiérrez-Ginés, María J; Pastor, Jesús

    2015-09-01

    Sewage sludges from urban wastewater treatment plants are often used to remediate degraded soils. However, the benefits of their use in metal-polluted soils remain unclear and need to be assessed in terms of factors besides soil fertility. This study examines the use of thermal-dried sewage sludge (TDS) as an amendment for heavy metal-polluted soil in terms of its effects on soil chemical properties, leachate composition, and the growth of native plant communities. To assess the response of the soil and its plant community to an increase in metal mobilization, the effects of TDS amendment were compared with those of the addition of a chelating agent (ethylenediaminetetraacetic acid [EDTA]). The experimental design was based on a real-case scenario in which soils from of an abandoned mine site were used in a greenhouse bioassay. Two doses of TDS and EDTA were applied to a soil containing high Pb, Zn, Cu, and Cd levels (4925, 5675, 404, and 25 mg kg, respectively). Soil pH was 6.4, and its organic matter content was 5.53%. The factors examined after soil amendment were soil fertility and heavy metal contents, leachate element losses, the plant community arising from the seed bank (plant cover, species richness and biodiversity, above/below ground biomass), and phytotoxic effects (chemical contents of abundant species). Thermal-dried sewage sludge emerged as a good phytostabilizer of Pb, Zn, Cu, and Cd given its capacity to reduce the plant uptake of metals and achieve rapid plant cover. This amendment also enhanced the retention of other elements in the plant root system and overall showed a better capacity to remediate soils polluted with several heavy metals. The addition of EDTA led to plant productivity losses and nutritional imbalances because it increased the mobility of several elements in the soil and its leachates.

  6. Response of autochthonous microbiota of diesel polluted soils to land-farming treatments.

    PubMed

    Silva-Castro, Gloria Andrea; Uad, Imane; Rodríguez-Calvo, Alfonso; González-López, Jesús; Calvo, Concepción

    2015-02-01

    This study investigated the response of autochthonous microorganisms of diesel polluted soils to land-farming treatments. Inorganic NPK (nitrogen, phosphorous, and potassium) fertilizer and Ivey surfactant were applied alone or in combination as biostimulating agents. The study was carried out in experimental separated land-farming plots performed with two soils: a sandy clay soil with low biological activity and a sandy clay soil with higher biological activity, contaminated with two concentrations of diesel: 10,000 and 20,000mgkg(-1). Bacterial growth, dehydrogenase activity and CO2 production were the biological parameters evaluated. Non-metric multidimensional scaling analysis proved that moisture content showed a tendency related to microbial growth and that heterotrophic and degrading microorganisms had the best relationship. Initial biological activity of soil influenced the response with 11.1% of variability attributed to this parameter. Soils with low activity had higher degree of response to nutrient addition.

  7. Bacterial degradation of aromatic pollutants: a paradigm of metabolic versatility.

    PubMed

    Díaz, Eduardo

    2004-09-01

    Although most organisms have detoxification abilities (i.e mineralization, transformation and/or immobilization of pollutants), microorganisms, particularly bacteria, play a crucial role in biogeochemical cycles and in sustainable development of the biosphere. Next to glucosyl residues, the benzene ring is the most widely distributed unit of chemical structure in nature, and many of the aromatic compounds are major environmental pollutants. Bacteria have developed strategies for obtaining energy from virtually every compound under oxic or anoxic conditions (using alternative final electron acceptors such as nitrate, sulfate, and ferric ions). Clusters of genes coding for the catabolism of aromatic compounds are usually found in mobile genetic elements, such as transposons and plasmids, which facilitate their horizontal gene transfer and, therefore, the rapid adaptation of microorganisms to new pollutants. A successful strategy for in situ bioremediation has been the combination, in a single bacterial strain or in a syntrophic bacterial consortium, of different degrading abilities with genetic traits that provide selective advantages in a given environment. The advent of high-throughput methods for DNA sequencing and analysis of gene expression (genomics) and function (proteomics), as well as advances in modelling microbial metabolism in silico, provide a global, rational approach to unravel the largely unexplored potentials of microorganisms in biotechnological processes thereby facilitating sustainable development.

  8. Estimating the biodegradation of pesticide in soils by monitoring pesticide-degrading gene expression.

    PubMed

    Monard, Cécile; Martin-Laurent, Fabrice; Lima, Oscar; Devers-Lamrani, Marion; Binet, Françoise

    2013-04-01

    Assessing in situ microbial abilities of soils to degrade pesticides is of great interest giving insight in soil filtering capability, which is a key ecosystem function limiting pollution of groundwater. Quantification of pesticide-degrading gene expression by reverse transcription quantitative PCR (RT-qPCR) was tested as a suitable indicator to monitor pesticide biodegradation performances in soil. RNA extraction protocol was optimized to enhance the yield and quality of RNA recovered from soil samples to perform RT-qPCR assays. As a model, the activity of atrazine-degrading communities was monitored using RT-qPCRs to estimate the level of expression of atzD in five agricultural soils showing different atrazine mineralization abilities. Interestingly, the relative abundance of atzD mRNA copy numbers was positively correlated to the maximum rate and to the maximal amount of atrazine mineralized. Our findings indicate that the quantification of pesticide-degrading gene expression may be suitable to assess biodegradation performance in soil and monitor natural attenuation of pesticide.

  9. The Chemophytostabilisation Process of Heavy Metal Polluted Soil.

    PubMed

    Grobelak, Anna; Napora, Anna

    2015-01-01

    Industrial areas are characterised by soil degradation processes that are related primarily to the deposition of heavy metals. Areas contaminated with metals are a serious source of risk due to secondary pollutant emissions and metal leaching and migration in the soil profile and into the groundwater. Consequently, the optimal solution for these areas is to apply methods of remediation that create conditions for the restoration of plant cover and ensure the protection of groundwater against pollution. Remediation activities that are applied to large-scale areas contaminated with heavy metals should mainly focus on decreasing the degree of metal mobility in the soil profile and metal bioavailability to levels that are not phytotoxic. Chemophytostabilisation is a process in which soil amendments and plants are used to immobilise metals. The main objective of this research was to investigate the effects of different doses of organic amendments (after aerobic sewage sludge digestion in the food industry) and inorganic amendments (lime, superphosphate, and potassium phosphate) on changes in the metals fractions in soils contaminated with Cd, Pb and Zn during phytostabilisation. In this study, the contaminated soil was amended with sewage sludge and inorganic amendments and seeded with grass (tall fescue) to increase the degree of immobilisation of the studied metals. The contaminated soil was collected from the area surrounding a zinc smelter in the Silesia region of Poland (pH 5.5, Cd 12 mg kg-1, Pb 1100 mg kg-1, Zn 700 mg kg-1). A plant growth experiment was conducted in a growth chamber for 5 months. Before and after plant growth, soil subsamples were subjected to chemical and physical analyses. To determine the fractions of the elements, a sequential extraction method was used according to Zeien and Brümmer. Research confirmed that the most important impacts on the Zn, Cd and Pb fractions included the combined application of sewage sludge from the food industry and

  10. The Chemophytostabilisation Process of Heavy Metal Polluted Soil

    PubMed Central

    Grobelak, Anna; Napora, Anna

    2015-01-01

    Industrial areas are characterised by soil degradation processes that are related primarily to the deposition of heavy metals. Areas contaminated with metals are a serious source of risk due to secondary pollutant emissions and metal leaching and migration in the soil profile and into the groundwater. Consequently, the optimal solution for these areas is to apply methods of remediation that create conditions for the restoration of plant cover and ensure the protection of groundwater against pollution. Remediation activities that are applied to large-scale areas contaminated with heavy metals should mainly focus on decreasing the degree of metal mobility in the soil profile and metal bioavailability to levels that are not phytotoxic. Chemophytostabilisation is a process in which soil amendments and plants are used to immobilise metals. The main objective of this research was to investigate the effects of different doses of organic amendments (after aerobic sewage sludge digestion in the food industry) and inorganic amendments (lime, superphosphate, and potassium phosphate) on changes in the metals fractions in soils contaminated with Cd, Pb and Zn during phytostabilisation. In this study, the contaminated soil was amended with sewage sludge and inorganic amendments and seeded with grass (tall fescue) to increase the degree of immobilisation of the studied metals. The contaminated soil was collected from the area surrounding a zinc smelter in the Silesia region of Poland (pH 5.5, Cd 12 mg kg-1, Pb 1100 mg kg-1, Zn 700 mg kg-1). A plant growth experiment was conducted in a growth chamber for 5 months. Before and after plant growth, soil subsamples were subjected to chemical and physical analyses. To determine the fractions of the elements, a sequential extraction method was used according to Zeien and Brümmer. Research confirmed that the most important impacts on the Zn, Cd and Pb fractions included the combined application of sewage sludge from the food industry and

  11. Multidimensional evaluation of soil pollution from railway tracks.

    PubMed

    Wierzbicka, Małgorzata; Bemowska-Kałabun, Olga; Gworek, Barbara

    2015-05-01

    Railway transport is a source of pollution to soils and living organisms by e.g. PAHs, PCBs, oil-derived products, pesticides and heavy metals. Soil toxicity evaluation requires chemical analyses, indicating the type and content of particular pollutants, as well as biological analyses, which allow assessing the reaction of organisms to these pollutants. This paper is focused on a multi-aspect evaluation of the degree of toxicity and pollution of soil in selected railway areas from north-eastern Poland by application of numerous biotests and chemical analyses. The soils were sampled on railway tracks from the following railway stations: Białystok Fabryczny, Siemianówka, Hajnówka, Iława Główna and Waliły. The most toxic soils occur on the railway tracks at Białystok Fabryczny and Siemianówka. They had a significant toxic effect on test organisms from various trophic levels. The contents of PAHs, PCBs, heavy metals, oil-derived hydrocarbons and pesticide residues were determined in the examined soils. In all cases the detected pollutants did not exceed the admissible levels. The highest content of oil-derived substances was noted in soils from Białystok Fabryczny and concentrations were moderate in soils from Siemianówka. Although the pollutants determined in soils from railway tracks did not exceed the admissible values, they had a toxic effect on numerous test organisms from different trophic levels. This suggests a synergistic effect of low concentrations (within the admissible levels) of several pollutants together, which resulted in a toxic effect on the organisms. Thus, there is a strong need of not only chemical, but also ecotoxicological analyses during the evaluation of environmental conditions. Based on data obtained from biological and chemical analyses, we concluded that railway transport may pose a hazard to the natural environment to a larger extent that hitherto expected.

  12. Soil pollution in Central district of Saint-Petersburg (Russia)

    NASA Astrophysics Data System (ADS)

    Terekhina, Natalia; Ufimtseva, Margarita

    2015-04-01

    Analysis of soil samples of upper horizon for the content of chemical elements (Fe, Mn, Cu, Zn, Pb, Ni, Cr, Co, Cd, Ba, Sr) was carried out by atomic emission with inductively coupled plasma. A relative indicator of soil contamination degree is a concentration coefficient, representing the ratio of metal content in tested soil samples to the local background value of the corresponding element. Total pollution index is calculated by the concentration coefficients, which are greater than 1, taking into account the hazard class of metals (1 class - Zn, Pb ,Cd; 2 - class Cr, Ni, Cu ,Со; 3 class - Fe, Mn, Sr, Ba). Analysis of trace element of urban soils demonstrated mosaic patterns of pollution for Central district. The method of correlation sets constructing and factor analysis revealed three groups of chemical elements having a strong and significant association with each other: Pb-Cu-Cd-Zn-Ba, Ni-Cr-Co, Fe-Mn. Elements of the first group are characterized by high values of concentration coefficient and are the main pollutants - their average content is 3-11 times higher than background values. Strontium does not have strong correlation with the other elements, and its lowest concentration coefficient indicates that the element can not be regarded as a pollutant. The spatial distribution of the total pollution index identified several sources of pollution, the origin of which may be different. The main reason is probably the impact of vehicle emissions, although local pollution of soil is possible (the soils, contaminated during reconstruction of lawns, dumping of construction materials, etc.). Differentiated assessment of database shows that 48% of samples refer to dangerous pollution category, 37% - to moderately dangerous category, 15% - to allowable category. Thus, almost half of the district is characterized as dangerous in terms of soil contamination. Solution of the problem of soil contamination is recommended in three ways: reducing the intensity of

  13. Survey of phthalate pollution in arable soils in China.

    PubMed

    Hu, Xiao-yu; Wen, Bei; Shan, Xiao-quan

    2003-08-01

    The problem of pollution by phthalates is of global concern due to their widespread occurrence, toxicity and endocrine disruption properties. The contamination by phthalates such as dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) in 23 arable soils throughout China was investigated to evaluate the present pollution situation. The survey results demonstrated that phthalates were ubiquitous pollutants in soils in China. The total concentrations of phthalates differed from one location to another, and ranged from 0.89 to 10.03 mg kg(-1) with a median concentration of 3.43 mg kg(-1). Among the phthalates, DEHP was dominant and detected in all 23 soils. DEP and DBP were also in abundance, and DMP was rarely detected. Similar contamination patterns were observed in all 23 soils. A distinct feature of phthalate pollution in China was that the average concentration in northern China was higher than that in southern China. In addition, a close relationship was observed between the concentration of phthalates in soils and the consumption of agricultural film. The correlation showed that the application of agriculture film might be a significant pollution source of phthalates in arable soils of China. The potential risk of phthalates in soils was assessed on the basis of current guide values and limits.

  14. DEGRADATION AND MIGRATION OF VINCLOZOLIN IN SAND AND SOIL

    EPA Science Inventory

    The migration of the dicarboximide fungicide vinclozolin and its principal degradation products through porous media was experimentally determined by simulating pesticide applications to a 23-30 mesh Ottawa sand and a North Carolina Piedmont, aquic hapludult soil in laboratory ...

  15. DEGRADATION AND MIGRATION OF VINCLOZOLIN IN SAND AND SOIL

    EPA Science Inventory

    The migration of the dicarboximide fungicide vinclozolin and its principal degradation products through porous media was experimentally determined by simulating pesticide applications to a 23-30 mesh Ottawa sand and a North Carolina Piedmont, aquic hapludult soil in laboratory ...

  16. Ultrastructure of two oil-degrading bacteria isolated from the tropical soil environment.

    PubMed

    Ilori, M O; Amund, D; Robinson, G K

    2000-01-01

    Two oil-degrading bacteria identified as Pseudomonas aeruginosa and Micrococcus luteus were isolated from crude-oil-polluted soils in Nigeria. The organisms were grown on n-hexadecane and sodium succinate and then examined for the presence of hydrocarbon inclusions. Inclusion bodies were found in n-hexadecane-grown cells and were absent in succinate-grown cells. Formation of hydrocarbon inclusion bodies appears to be a general phenomenon among hydrocarbon utilizers.

  17. Nanoscale zerovalent iron-mediated degradation of DDT in soil.

    PubMed

    Han, Yuling; Shi, Nan; Wang, Huifang; Pan, Xiong; Fang, Hua; Yu, Yunlong

    2016-04-01

    Nanoscale zerovalent iron (nZVI)-mediated degradation of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) was investigated in a spiked soil under different conditions (iron sources, iron dosage, soil moisture, temperature, and soil types) and DDT-contaminated field. The degradation efficiency of p,p'-DDT by nZVI and nZVI coated with sodium oleate (SO-nZVI) was much higher than that by nZVI coated with polyimide (PI-nZVI). The rapid degradation of p,p'-DDT by nZVI only occurred in flooded soil. The degradation half-life of p,p'-DDT decreased significantly from 58.3 to 27.6 h with nZVI dosage from 0.5 to 2.0% and from 46.5 to 32.0 h with temperature from 15 to 35 °C. The degradation efficiency of p,p'-DDT by nZVI differed in Jinhua (JH), Jiaxing (JX), Xiaoshan (XS), Huajiachi (HJC), and Heilongjiang (HLJ) soils. A good correlation was found between the degradation half-life of p,p'-DDT and multiple soil properties. The probable nZVI-mediated degradation pathway of p,p'-DDT in soil was proposed as DDT → DDD/DDE → DDNS → DDOH based on the metabolites identified by GC-MS. The in situ degradation efficiency of residual DDTs in a contaminated field was profoundly enhanced by the addition of nZVI as compared to the control. It is concluded that nZVI might be an efficient agent for the remediation of DDT-contaminated soil under anaerobic environment.

  18. Spatial distribution of soil lead pollution in Milwaukee County, Wisconsin

    SciTech Connect

    Brinkmann, R.

    1989-01-01

    The spatial distribution of lead pollution in soils of Milwaukee County, Wisconsin, was investigated to find the patterns and extent of health-threatening contamination. Samples were collected within three distinct land-use types: (i) lawns and gardens, (ii) major east-west arterials, and (iii) private properties at site-specific locations. Three-hundred and sixty-four soil samples were collected from lawns and gardens throughout the county; a total of 263 soil samples were collected along College Avenue, Oklahoma Avenue, Greenfield Avenue, Wisconsin Avenue, North Avenue, Capitol Drive, and Brown Deer Road, and a total of 55 soil samples were collected from three private properties. Several distinct patterns emerged from the mapped data. Broadly, soil lead pollution in lawns and gardens was highest in the central city and decreased north, south, and west toward the county lines and suburban fringe. Also, soil lead pollution along major arterials decreased away from busy intersections and was generally eliminated east of 42nd Street. At the three locations of intense sampling for site-specific examination, soil lead was concentrated within one meter of painted structures. Peripheral to the one meter zone, background levels of lead were found except in the central city where elevated soil lead levels were found in lawns. Health-threatening lead levels (>500 ppm) were found in soils collected using all three approaches: 24% of 11 soils collected from lawns and gardens; 43% of soils collected from major east-west arterials; and 27% of the soils collected from all three intensely examined properties. The sources of lead pollution in soil were more clearly suggested in intense sampling within small private properties. Lead-based paint caused contamination within one meter of painted structures and airborne lead from automobile exhaust outside that zone.

  19. Relationship between bacterial diversity and function under biotic control: the soil pesticide degraders as a case study

    PubMed Central

    Monard, Cécile; Vandenkoornhuyse, Philippe; Le Bot, Barbara; Binet, Françoise

    2011-01-01

    In soil, the way biotic parameters impact the relationship between bacterial diversity and function is still unknown. To understand these interactions better, we used RNA-based stable-isotope probing to study the diversity of active atrazine-degrading bacteria in relation to atrazine degradation and to explore the impact of earthworm-soil engineering with respect to this relationship. Bulk soil, burrow linings and earthworm casts were incubated with 13C-atrazine. The pollutant degradation was quantified by liquid chromatography–mass spectrometry for 8 days, whereas active atrazine degraders were identified at 2 and 8 days by sequencing the 16S ribosomal RNA in the 13C-RNA fractions from the three soil microsites. An original diversity of atrazine degraders was found. Earthworm soil engineering greatly modified the taxonomic composition of atrazine degraders with dominance of α-, β- and γ-proteobacteria in burrow linings and of Actinobacteria in casts. Earthworm soil bioturbation increased the γ-diversity of atrazine degraders over the soil microsites generated. Atrazine degradation was enhanced in burrow linings in which primary atrazine degraders, closely related to Pelomonas aquatica, were detected only 2 days after atrazine addition. Atrazine degradation efficiency was not linearly related to the species richness of degraders but likely relied on keystone species. By enhancing soil heterogeneity, earthworms sustained high phylogenetic bacterial diversity and exerted a biotic control on the bacterial diversity–function relationships. Our findings call for future investigations to assess the ecological significance of biotic controls on the relationships between diversity and function on ecosystem properties and services (for example, soil detoxification) at larger scales. PMID:21160539

  20. Relationship between bacterial diversity and function under biotic control: the soil pesticide degraders as a case study.

    PubMed

    Monard, Cécile; Vandenkoornhuyse, Philippe; Le Bot, Barbara; Binet, Françoise

    2011-06-01

    In soil, the way biotic parameters impact the relationship between bacterial diversity and function is still unknown. To understand these interactions better, we used RNA-based stable-isotope probing to study the diversity of active atrazine-degrading bacteria in relation to atrazine degradation and to explore the impact of earthworm-soil engineering with respect to this relationship. Bulk soil, burrow linings and earthworm casts were incubated with (13)C-atrazine. The pollutant degradation was quantified by liquid chromatography-mass spectrometry for 8 days, whereas active atrazine degraders were identified at 2 and 8 days by sequencing the 16S ribosomal RNA in the (13)C-RNA fractions from the three soil microsites. An original diversity of atrazine degraders was found. Earthworm soil engineering greatly modified the taxonomic composition of atrazine degraders with dominance of α-, β- and γ-proteobacteria in burrow linings and of Actinobacteria in casts. Earthworm soil bioturbation increased the γ-diversity of atrazine degraders over the soil microsites generated. Atrazine degradation was enhanced in burrow linings in which primary atrazine degraders, closely related to Pelomonas aquatica, were detected only 2 days after atrazine addition. Atrazine degradation efficiency was not linearly related to the species richness of degraders but likely relied on keystone species. By enhancing soil heterogeneity, earthworms sustained high phylogenetic bacterial diversity and exerted a biotic control on the bacterial diversity-function relationships. Our findings call for future investigations to assess the ecological significance of biotic controls on the relationships between diversity and function on ecosystem properties and services (for example, soil detoxification) at larger scales.

  1. Degradation of metalaxyl and folpet by filamentous fungi isolated from Portuguese (Alentejo) vineyard soils.

    PubMed

    Martins, M Rosário; Pereira, Pablo; Lima, Nelson; Cruz-Morais, Júlio

    2013-07-01

    Degradation of xenobiotics by microbial populations is a potential method to enhance the effectiveness of ex situ or in situ bioremediation. The purpose of this study was to evaluate the impact of repeated metalaxyl and folpet treatments on soil microbial communities and to select soil fungal strains able to degrade these fungicides. Results showed enhanced degradation of metalaxyl and folpet in vineyards soils submitted to repeated treatments with these fungicides. Indeed, the greatest degradation ability was observed in vineyard soil samples submitted to greater numbers of treatments. Respiration activities, as determined in the presence of selective antibiotics in soil suspensions amended with metalaxyl and folpet, showed that the fungal population was the microbiota community most active in the degradation process. Batch cultures performed with a progressive increase of fungicide concentrations allowed the selection of five tolerant fungal strains: Penicillium sp. 1 and Penicillium sp. 2, mycelia sterila 1 and 3, and Rhizopus stolonifer. Among these strains, mycelium sterila 3 and R. stolonifer presented only in vineyard soils treated with repeated application of these fungicides and showed tolerance >1,000 mg l(-1) against commercial formulations of metalaxyl (10 %) plus folpet (40 %). Using specific methods for inducing sporulation, mycelium sterila 3 was identified as Gongronella sp. Because this fungus is rare, it was compared using csM13-polymerase chain reaction (PCR) with the two known species, Gongronella butleri and G. lacrispora. The high tolerance to metalaxyl and folpet shown by Gongronella sp. and R. stolonifer might be correlated with their degradation ability. Our results point out that selected strains have potential for the bioremediation of metalaxyl and folpet in polluted soil sites.

  2. Tracking permafrost soil degradation through sulphur biogeochemical tracers

    NASA Astrophysics Data System (ADS)

    Canario, João; Santos, Margarida C.; Vieira, Gonçalo; Vincent, Warwick F.

    2017-04-01

    Rising temperatures are contributing to the rapid degradation of Arctic permafrost soils. Several studies have been using some biogeochemical tracers as indicators of the organic matter degradation although fewer attention has been given to sulphur. In fact, the chemistry of this element is of environmental importance because it plays a key role in the degradation of natural organic matter and influences the partitioning, speciation and fate of other trace elements. To better understand the role of sulphur in biogeochemical processes in permafrost soils several campaigns were undertaken in the Canadian subarctic region of Kuujjuarapik-Whapmagoostui and Umiujaq (QC) as a part of the Canadian ADAPT and the Portuguese PERMACHEM projects. In four sites along those regions soil samples were collected and pore water were extracted. Dissolved sulphur compounds (sulphide and sulphate) were determined in water samples while in soils particulate sulphides, pyrite and elemental sulphur were quantified by voltammetry. Organic sulphur compounds were identified using 33SssNMR and X-ray diffraction both in powder and single crystal analysis were used to identify crystalline sulphides. Finally, subsamples of soils and water samples were analysed for total particulate and dissolved organic carbon. The results showed that sulphur composition depends largely on the origin of permafrost soils. In soils originated from organic-rich palsas, the proportion of organic sulphur (% of the total) is higher than 50%, while in mineral lithalsa soils the opposite was found. In both cases the origin of sulphur was mainly from plant organic matter degradation. The combined structural and chemical analysis allowed the identified different stages of soil degradation by determined the ratio between inorganic and organic sulphur species and by following the different NMR and XRD spectra. These preliminary results pointed to the importance of the sulphur biogeochemistry in permafrost soils and provide

  3. The Degradation of Organic Pollutants by Bubble Discharge in Water

    NASA Astrophysics Data System (ADS)

    Zhu, Linan; Wang, Yongjun; Ren, Zhijun; Liu, Guifang; Kang, Kai

    2013-10-01

    Organic pollutants could be degraded by using bubble discharge in water with gas aeration in the discharge reactor and more plasma can be generated in the discharge process. When pulsed high voltage was applied between electrodes with gas aerated into the reactor, it showed that bubbles were broken, which meant that breakdown took place. It could also be observed that the removal rate of phenol increased with increasing discharge voltage or pulse frequency, and with reducing initial phenol concentration or solution electric conductivity. It could remove more amount of phenol by oxygen aeration. With increasing oxygen flow rate, the removal rate increased. There was little difference with air or nitrogen aeration for phenol removal. The solution temperature after discharge increased to a great extent. However, this part of energy consumption did not contribute to the reaction, which led to a reduction in the energy utilization efficiency.

  4. [Soil nematode as a bioindicator of environment pollution].

    PubMed

    Zhang, Wei; Song, Yufang; Sun, Tieheng; Song, Xueying; Zhou, Qixing

    2004-10-01

    As a part of mesofauna in soil ecosystem, nematode plays an important role in essential soil processes. Because of its unique attributes, nematode was widely used in the study of soil health indication. Based on the current studies at home and abroad, this paper discussed the function and application of nematode in indicating and diagnosing soil pollution, and the indices (maturity index, diversity index, similarity index, key species, N/C ratio, and physiological index) and their characteristics of nematode communities used as indicators. As a useful index of bioindicators in ecotoxicological diagnosis, the prospect of soil nematode application was of potential.

  5. A microcosm system and an analytical protocol to assess PAH degradation and metabolite formation in soils.

    PubMed

    Arias, Lida; Bauzá, Jorge; Tobella, Joana; Vila, Joaquim; Grifoll, Magdalena

    2008-06-01

    During bioremediation of polycyclic aromatic hydrocarbon (PAH)-polluted soils accumulation of polar metabolites resulting from the biological activity may occur. Since these polar metabolites are potentially more toxic than the parental products, a better understanding of the processes involved in the production and fate of these oxidation products in soil is needed. In the present work we describe the design and set-up of a static soil microcosm system and an analytical methodology for detection of PAHs and their oxidation products in soils. When applied to a soil contaminated with phenanthrene, as a model PAH, and 1-hydroxy-2-naphthoic acid, diphenic acid, and phthalic acid as putative metabolites, the extraction and fractionation procedures resulted in recoveries of 93%, 89%, 100%, and 89%, respectively. The application of the standardized system to study the biodegradation of phenanthrene in an agricultural soil with and without inoculation of the high molecular weight PAH-degrading strain Mycobacterium sp. AP1, demonstrates its suitability for determining the environmental fate of PAHs in polluted soils and for evaluating the effect of bioremediative treatments. In inoculated microcosms 35% of the added phenanthrene was depleted, 19% being recovered as CO(2) and 3% as diphenic acid. The latter, together with other two unidentified metabolites, accumulated in soil.

  6. Removal of alkylphenols from polluted sites using surfactant-assisted soil washing and photocatalysis.

    PubMed

    Davezza, Manuela; Fabbri, Debora; Prevot, Alessandra Bianco; Pramauro, Edmondo

    2011-06-01

    Surfactant-assisted soil washing and photocatalysis are well-known remediation processes of environmental concern. The application of photocatalysis to treat soil washing extracts containing 4-methylphenol, 4-ethylphenol and 4-tert-butylphenol in the presence of nonionic (C(12)E(8) and C(12)E(23)) and anionic (SDS) surfactants and some of their binary mixtures was investigated in this work by studying the pollutants degradation in the presence of TiO(2) dispersions irradiated with simulated solar light. Clean soil samples were spiked with the investigated alkylphenols. Aqueous solutions of the chosen surfactants were placed in contact for some hours with the spiked soil samples in a rotatory mixer. The pollutants recoveries were evaluated via HPLC analysis. Photocatalytic experiments were performed in solarbox on aqueous solutions and on aqueous surfactant solutions containing the pollutants. The pollutants removal from the soil was proven effective using the examined surfactant solutions. The photocatalytic treatment of the wastes was faster using Brij 35, but also SDS and C(12)E(8)-SDS mixtures can be applied. After 2-5 h the complete pollutants abatement was obtained, depending on the surfactant chosen and on the amount of TiO(2) employed. On the contrary, the treatment of wastes containing C(12)E(8) was an extremely slow process. The photocatalytic approach can be applied to remove the examined aromatic pollutants from the washing wastes, confirming the viable coupling between this advanced oxidation method and the surfactant-based soil remediation treatments. Surfactant adsorption onto TiO(2) and micelles concentration play a dominant role.

  7. Optical thickness as related to pollutant episodes and the concentration of visibility degrading pollutants

    NASA Technical Reports Server (NTRS)

    Prospero, J. M.; Savoie, D.; Snowdon, T.; Ewbank, P.

    1983-01-01

    A network of six sun photometers was placed in the central and northeast United States during the months of July through October, 1931. The objective of the program was to obtain measurements of atmospheric turbidity which can be related to the concentration of visibility-degrading pollutants in the atmosphere. These measurements serve as ground truth for a program to develop remote sensing techniques for measuring the vertically integrated aerosol concentrations in pollution episodes. The sun photometers measure the direct solar radiation in four passbands: 380 nm, 500 nm, 875 nm and 940 nm. The first three passbands will be used for measuring the aerosol optical depth and the last for measuring precipitable water.

  8. Degradation of estrogenic hormones in a silt loam soil.

    PubMed

    Xuan, Richeng; Blassengale, Alma A; Wang, Qiquan

    2008-10-08

    Estrogenic hormones are endocrine-disrupting compounds, which disrupt the endocrine system function of animals and humans by mimicking and/or antagonizing endogenous hormones. With the application of sludge biosolid and animal manure as alternative fertilizers in agricultural lands, estrogens enter the soil and become an environmental concern. The degradation kinetics of 17beta-estradiol, an estrogenic hormone of major concern, in a silt loam soil were investigated in this study. It was found that 17beta-estradiol degraded rapidly in nonsterilized soil with a half-life of 0.17 day. The degradation rate constant was proportional to the percentage of nonsterilized soil, indicating that microorganisms are directly responsible for the rapid degradation of 17beta-estradiol in soil. The half-life of 17beta-estradiol in 20% nonsterilized soil was slightly shortened from 1.3 to 0.69 day with the increase of soil moisture from 10 to 20% and was greatly decreased from 4.9 to 0.92 day with the increase of temperature from 15 to 25 degrees C. The coexistence of 40 micromol kg (-1) sulfadimethoxine, a veterinary antibiotic, decreased the degradation rate constant of 17beta-estradiol from 0.750 +/- 0.038 to 0.492 +/- 0.016 day (-1). The degradation kinetics of another three estrogenic hormones, including 17alpha-estradiol, estrone, and estriol, were also investigated and compared. Estrone was identified as a degradation product of 17beta-estradiol and the most persistent hormone among the four investigated estrogens. Estriol was observed in the degradation of estrone and 17alpha-estradiol.

  9. Microbial removal of toxic metals from a heavily polluted soil

    NASA Astrophysics Data System (ADS)

    Nicolova, Marina; Spasova, Irena; Georgiev, Plamen; Groudev, Stoyan

    2015-04-01

    Samples of a leached cinnamonic forest soil heavily polluted with uranium and some toxic heavy metals (mainly copper, zinc and cadmium) were subjected to cleaning by means of bioleaching with acidophilic chemolithotrophic bacteria. The treatment was carried out in a green house in which several plots containing 150 kg of soil each were constructed. The effect of some essential environmental factors such as pH, humidity, temperature and contents of nutrients on the cleaning process was studied. It was found that under optimal conditions the content of pollutants were decreased below the relevant permissible levels within a period of 170 days. The soil cleaned in this way was characterized by a much higher production of biomass of different plants (alfalfa, clover, red fescue, vetch) than the untreated polluted soil.

  10. The Effects of Organic Pollutants in Soil on Human Health

    NASA Astrophysics Data System (ADS)

    Burgess, Lynn

    2013-04-01

    The soil has always been depository of the organic chemicals produced naturally or anthropogenically. Soil contamination is a serious human and environmental problem. A large body of evidence has shown the risks of adverse health effects with the exposure to contaminated soil due to the large quantities of organic chemicals used in agriculture and urban areas that have a legacy of environmental pollution linked to industrial activities, coal burning, motor vehicle emissions, waste incineration and waste dumping. In agricultural areas, because of the effort to provide adequate quantities of agricultural products, farmers have been using an increasing amount of organic chemicals, but the resulting pollution has enormous potential for environmental damage. The types of organic pollutants commonly found in soils are polychlorinated biphenyls, polybrominated biphenyls, polychlorinated dibenzofurans, polycyclic aromatic hydrocarbons, organophosphorus and carbamate insecticides, herbicides and organic fuels, especially gasoline and diesel. Another source of soil pollution is the complex mixture of organic chemicals, metals and microorganisms in the effluent from septic systems, animal wastes and other sources of biowaste. The soils of the world are a vast mixture of chemicals and although conditions are such that an individual is rarely exposed to a single compound, the great majority of people are exposed to a vast chemical mixture of organics, their metabolites, and other compounds at low concentrations Human exposure to organic pollutants in the soil is an area of toxicology that is very difficult to study due to the low concentration of the pollutants. The toxicological studies of single organic pollutants found in soils are limited and research on the metabolites and of chemical mixtures is very limited. The majority of toxicological studies are conducted at relatively high doses and for short periods of exposure. This makes the application of this data to exposure

  11. Carbazole degradation in the soil microcosm by tropical bacterial strains

    PubMed Central

    Salam, Lateef B.; Ilori, Matthew O.; Amund, Olukayode O.

    2015-01-01

    In a previous study, three bacterial strains isolated from tropical hydrocarbon-contaminated soils and phylogenetically identified as Achromobacter sp. strain SL1, Pseudomonas sp. strain SL4 and Microbacterium esteraromaticum strain SL6 displayed angular dioxygenation and mineralization of carbazole in batch cultures. In this study, the ability of these isolates to survive and enhance carbazole degradation in soil were tested in field-moist microcosms. Strain SL4 had the highest survival rate (1.8 x 107 cfu/g) after 30 days of incubation in sterilized soil, while there was a decrease in population density in native (unsterilized) soil when compared with the initial population. Gas chromatographic analysis after 30 days of incubation showed that in sterilized soil amended with carbazole (100 mg/kg), 66.96, 82.15 and 68.54% were degraded by strains SL1, SL4 and SL6, respectively, with rates of degradation of 0.093, 0.114 and 0.095 mg kg−1 h−1. The combination of the three isolates as inoculum in sterilized soil degraded 87.13% carbazole at a rate of 0.121 mg kg−1 h−1. In native soil amended with carbazole (100 mg/kg), 91.64, 87.29 and 89.13% were degraded by strains SL1, SL4 and SL6 after 30 days of incubation, with rates of degradation of 0.127, 0.121 and 0.124 mg kg−1 h−1, respectively. This study successfully established the survivability (> 106 cfu/g detected after 30 days) and carbazole-degrading ability of these bacterial strains in soil, and highlights the potential of these isolates as seed for the bioremediation of carbazole-impacted environments. PMID:26691461

  12. Soil degradation and amendment effects on soil properties, microbial communities, and plant growth

    NASA Astrophysics Data System (ADS)

    Gebhardt, M.; Fehmi, J. S.; Rasmussen, C.; Gallery, R. E.

    2015-12-01

    Human activities that disrupt soil properties are fundamentally changing ecosystems. Soil degradation, caused by anthropogenic disturbance can decrease microbial abundance and activity, leading to changes in nutrient availability, soil organic matter, and plant establishment. The addition of amendments to disturbed soils have the potential ameliorate these negative consequences. We studied the effects of soil degradation, via an autoclave heat shock method, and the addition of amendments (biochar and woodchips) on microbial activity, soil carbon and nitrogen availability, microbial biomass carbon and nitrogen content, and plant growth of ten plant species native to the semi-arid southwestern US. Relative to non-degraded soils, microbial activity, measured via extracellular enzyme assays, was significantly lower for all seven substrates assayed. These soils also had significantly lower amounts of carbon assimilated into microbial biomass but no change in microbial biomass nitrogen. Soil degradation had no effect on plant biomass. Amendments caused changes in microbial activity: biochar-amended soils had significant increases in potential activity with five of the seven substrates measured; woodchip amended soils had significant increases with two. Soil carbon increased with both amendments but this was not reflected in a significant change in microbial biomass carbon. Biochar-amended soils had increases in soil nitrogen availability but neither amendment caused changes in microbial biomass nitrogen. Biochar amendments had no significant effect on above- or belowground plant biomass while woodchips significantly decreased aboveground plant biomass. Results show that soil degradation decreases microbial activity and changes nutrient dynamics, but these are not reflected in changes in plant growth. Amendments provide nutrient sources and change soil pore space, which cause microbial activities to fluctuate and may, in the case of woodchips, increase plant drought

  13. Use of phytoremediation and biochar to remediate heavy metal polluted soils: a review

    NASA Astrophysics Data System (ADS)

    Paz-Ferreiro, J.; Lu, H.; Fu, S.; Méndez, A.; Gascó, G.

    2014-02-01

    Anthropogenic activities are resulting in an increase of the use and extraction of heavy metals. Heavy metals cannot be degraded and hence accumulate in the environment, having the potential to contaminate the food chain. This pollution threatens soil quality, plant survival and human health. The remediation of heavy metals deserves attention, but it is impaired by the cost of these processes. Phytoremediation and biochar are two sound environmental technologies which could be at the forefront to mitigate soil pollution. This review provides an overview of the state of the art of the scientific research on phytoremediation and biochar application to remediate heavy-metal-contaminated soils. Research to date has attempted only in a limited number of occasions to combine both techniques, however we discuss the potential advantages of combining both, and the potential mechanisms involved in the interaction between phytoremediators and biochar. We identified specific research needs to ensure a sustainable use of phytoremediation and biochar as remediation tools.

  14. Rapid degradation of endosulfan by zero-valent zinc in water and soil.

    PubMed

    Cong, Lujing; Guo, Jing; Liu, Jisong; Shi, Haiyan; Wang, Minghua

    2015-03-01

    Endosulfan has been included in the list of persistent organic pollutants (POPs) in 2011. The degradation of endosulfan by zero-valent zinc in water and soil was first investigated. The results showed that >90% endosulfan could be degraded in 180 min. The degradation was accelerated under acidic conditions with the absence of dissolved oxygen, while the nature of the soil only exhibited a negligible effect. The half-life was decreased from 130.75 min to 41.75 min with the increment of Zn(0) from 0.1 g to 1 g in soil. The use of Zn(0) was more effective than Fe(0) for the degradation of endosulfan with a half-life of 110 min and 330 min. The cationic surfactant was more effective at enhancing the degradation of endosulfan than anionic and nonionic surfactant. The degradation pathway was speculated, and four chlorine of endosulfan were proposed to be reduced. The method exhibited obvious advantages over traditional endosulfan treatments, and the research results will lay a foundation for practical application of the method.

  15. [Petroleum pollution and the microbial community structure in the soil of Shengli Oilfield].

    PubMed

    Liu, Jian; Song, Xue-Ying; Sun, Rui-Lian; Xie, Fu-Ju; Wang, Ren-Qing; Wang, Wen-Xing

    2014-03-01

    Soils around a new oil well (2011- ) and an old oil well (1966-2003) were sampled to investigate the characteristics of petroleum pollution in the oilfield. The structure of soil microbial community was analyzed by PCR-DGGE and clone sequencing techniques. Results showed that the soils around the two oil wells were generally contaminated with petroleum, and the concentrations of total petroleum hydrocarbons mostly exceeded the threshold of the environmental quality standards of soil (500 mg x kg(-1)). The total petroleum hydrocarbons concentration of the polluted soil was significantly positively correlated with the contents of organic carbon, total nitrogen and available potassium, respectively. The microbial diversity index in the soil around the old oil well decreased with the increasing total petroleum hydrocarbons concentration, however, it was reversed for the soil around the new oil well. Sequence analysis of the prominent bands in DGGE profiles showed that some dominant species existed in the petroleum-contaminated soils around the oil wells and mostly were oil-associated and hydrocarbon degrading bacteria, including Microbacterium, Streptomyces, Dietzia, Flavobacterium, alpha-Proteobacteria, and gamma-Proteobacteria.

  16. [Bio-indicating function of soil protozoa to environmental pollution].

    PubMed

    Song, Xueying; Song, Yufang; Sun, Tieheng; Zhang, Wei; Zhou, Qixing

    2004-10-01

    Due to the abundant species and huge biomass, soil protozoa play an important role in soil ecosystem. As a bio-indicator, soil protozoa have many advantages over other soil animals. Studies on the community structures, quantities, and dynamic variations of biodiversity of soil protozoa could provide powerful means to evaluate natural environmental changes and to monitor the environmental pollution brought by anthropic activities. Based on the current study at home and abroad, this paper gave a review on the function of soil protozoa in ecosystems, their advantages as bio-indicator, and their responses to environmental factors, soil contaminants and the change of atmospheric CO2. The application prospect of soil protozoa in eco-toxicity diagnosis was also discussed.

  17. Understanding and enhancing soil health: the solution for reversing soil degradation

    USDA-ARS?s Scientific Manuscript database

    This special issue of Sustainability documents both the magnitude and global prevalence of soil degradation and helps illustrate (1) various factors contributing to the problem, (2) its past and current impacts, and (3) projected consequences to humankind if degradation of our fragile soil resource...

  18. Adsorption and degradation of PAH compounds in soil. Progress report. [Acenaphthene, naphthalene

    SciTech Connect

    Mihelcic, J.R.; Luthy, R.G.

    1986-05-01

    Organic contaminant fate in soil/water systems can be affected by the biological characteristics of the soil and of the pollutant. This work investigates biodegradation of polycyclic aromatic hydrocarbons (PAH) in a soil environment under denitrification conditions. The objectives of the work over the past quarter were to compile and assess literature related to biological degradation of PAH under denitrification conditions, and to perform experiments to verify PAH degradation under denitrification conditions. Information from the literature is being utilized to develop a model to describe organic substrate usage when PAH is discharged into soil/water environments devoid of oxygen. An important concept which will be incorporated into the model is that PAH competes with other naturally occurring organic carbon sources as a substrate for biological metabolism in soil/water systems. Experiments were conducted to examine the degradation of naphthalene and acenaphthene under denitrification conditions. Several tests were also performed to examine denitrification without the presence of PAH to assess the contribution of available soil carbon as an organic carbon substrate. Results are discussed. 10 refs., 12 figs.

  19. Biodegradation of petroleum sludge and petroleum polluted soil by a bacterial consortium: a laboratory study.

    PubMed

    Gojgic-Cvijovic, G D; Milic, J S; Solevic, T M; Beskoski, V P; Ilic, M V; Djokic, L S; Narancic, T M; Vrvic, M M

    2012-02-01

    This article presents a study of the efficiency and degradation pattern of samples of petroleum sludge and polluted sandy soil from an oil refinery. A bacterial consortium, consisting of strains from the genera Pseudomonas, Achromobacter, Bacillus and Micromonospora, was isolated from a petroleum sludge sample and characterized. The addition of nitrogen and phosphorus nutrients and a chemical surfactant to both the samples and bioaugmentation to the soil sample were applied under laboratory conditions. The extent of biodegradation was monitored by the gravimetric method and analysis of the residual oil by gas chromatography. Over a 12-week experiment, the achieved degree of TPH (total petroleum hydrocarbon) degradation amounted to 82-88% in the petroleum sludge and 86-91% in the polluted soil. Gas chromatography-mass spectrometry was utilized to determine the biodegradability and degradation rates of n-alkanes, isoprenoids, steranes, diasteranes and terpanes. Complete degradation of the n-alkanes and isoprenoids fractions occurred in both the samples. In addition, the intensities of the peaks corresponding to tricyclic terpenes and homohopanes were decreased, while significant changes were also observed in the distribution of diasteranes and steranes.

  20. Degradation of ambient carbonyl sulfide by Mycobacterium spp. in soil.

    PubMed

    Kato, Hiromi; Saito, Masahiko; Nagahata, Yoshiko; Katayama, Yoko

    2008-01-01

    The ability to degrade carbonyl sulfide (COS) was confirmed in seven bacterial strains that were isolated from soil, without the addition of COS. Comparative 16S rRNA gene sequence analysis indicated that these isolates belonged to the genera Mycobacterium, Williamsia and Cupriavidus. For example, Mycobacterium sp. strain THI401, grown on PYG agar medium, was able to degrade an initial level of 30 parts per million by volume COS within 1 h, while 60 % of the initial COS was decreased by abiotic conversion in 30 h. Considering natural COS flux between soil and the atmosphere, COS degradation by these bacteria was confirmed at an ambient level of 500 parts per trillion by volume (p.p.t.v.), using sterilized soil to cultivate the bacterium. Autoclave sterilization of soil resulted in a small amount of COS emission, while Mycobacterium spp. degraded COS at a faster rate than it was emitted from the soil, and reduced the COS mixing ratio to a level that was lower than the ambient level: THI401 degraded COS from an initial level of 530 p.p.t.v. to a level of 330 p.p.t.v. in 30 h. These results provide experimental evidence of microbial activity in soil as a sink for atmospheric COS.

  1. Toluene-Degrading Bacteria Are Chemotactic towards the Environmental Pollutants Benzene, Toluene, and Trichloroethylene

    PubMed Central

    Parales, Rebecca E.; Ditty, Jayna L.; Harwood, Caroline S.

    2000-01-01

    The bioremediation of polluted groundwater and toxic waste sites requires that bacteria come into close physical contact with pollutants. This can be accomplished by chemotaxis. Five motile strains of bacteria that use five different pathways to degrade toluene were tested for their ability to detect and swim towards this pollutant. Three of the five strains (Pseudomonas putida F1, Ralstonia pickettii PKO1, and Burkholderia cepacia G4) were attracted to toluene. In each case, the response was dependent on induction by growth with toluene. Pseudomonas mendocina KR1 and P. putida PaW15 did not show a convincing response. The chemotactic responses of P. putida F1 to a variety of toxic aromatic hydrocarbons and chlorinated aliphatic compounds were examined. Compounds that are growth substrates for P. putida F1, including benzene and ethylbenzene, were chemoattractants. P. putida F1 was also attracted to trichloroethylene (TCE), which is not a growth substrate but is dechlorinated and detoxified by P. putida F1. Mutant strains of P. putida F1 that do not oxidize toluene were attracted to toluene, indicating that toluene itself and not a metabolite was the compound detected. The two-component response regulator pair TodS and TodT, which control expression of the toluene degradation genes in P. putida F1, were required for the response. This demonstration that soil bacteria can sense and swim towards the toxic compounds toluene, benzene, TCE, and related chemicals suggests that the introduction of chemotactic bacteria into selected polluted sites may accelerate bioremediation processes. PMID:10966434

  2. Catabolic mobile genetic elements and their potential use in bioaugmentation of polluted soils and waters.

    PubMed

    Top, Eva M; Springael, Dirk; Boon, Nico

    2002-11-01

    Genes that encode the degradation of both naturally occurring and xenobiotic organic compounds are often located on plasmids, transposons or other mobile and/or integrative elements. The list of published reports of such mobile genetic elements (MGEs) keeps growing as researchers continue to isolate and characterize new degrading bacteria and their corresponding degradative genes. There is also growing evidence that horizontal exchange of catabolic (degradative) genes among bacteria in microbial communities plays an important role in the evolution of catabolic pathways. Around 10 years ago the hypothesis was raised that we might be able to accelerate this natural gene exchange and pathway construction by introducing and subsequently spreading degradative genes, located on MGEs, into well established, competitive indigenous microbial populations as a means of bioaugmentation of polluted soils and waters. During the last decade, only a few reports on successful MGE- mediated bioaugmentation have been published. After summarizing the diversity of degradative MGEs, this review presents an overview of studies that have monitored the transfer of degradative genes in soil microcosms and in activated sludge and other wastewater treatment reactors, with emphasis on those that have clearly shown a direct effect of gene transfer on accelerated biodegradation. A few successful cases suggest that the strategy could indeed work under specific conditions, such as when the in situ degradation potential is absent and the pollutant degrading transconjugants can grow and become numerically dominant populations in the bacterial community. Further studies in this area are obviously needed to improve our current knowledge on the efficiency of gene dissemination as a tool in bioremediation.

  3. Soil degradation in wooded rangelands of southwest Spain

    NASA Astrophysics Data System (ADS)

    Schnabel, S.; Lavado Contador, J. F.; Gómez Gutiérrez, Á.

    2009-04-01

    The paper presents a review on soil degradation studies carried out since 1990 in wooded rangelands in Extremadura. In the semiarid and subhumid parts of the south-western Iberian Peninsula open evergreen woodlands dominated by Quercus species are widespread (dehesas and montados). They are composed of grasslands with a varying degree of tree cover, ranging from treeless to more than 80 individuals per hectare. In some areas shrubs form a third component of the vegetation. Dehesas are subject to a complex exploitation system with agro-silvo-pastoral land use. The dominant soil degradation phenomena include different forms of water erosion and physical and biological degradation. Regarding soil erosion and surface hydrology, research has been carried out at different spatial scales. Sheetwash and overland flow were investigated along hillslopes and in microplots, whereas gully erosion and runoff production were monitored in small experimental catchments. Recently, physical and biological degradation has been studied in a large number of farms, representing the most important types of rangelands in the region of Extremadura. This included a rapid appraisal of degradation features, the determination of soil properties and a study on the distribution and activity of gullies. Soil degradation varies strongly with regard to the natural factors, but also with respect to land use and management. Sheetwash (interrill erosion) is the dominant process on hillslopes, with a mean soil loss rate of 0.63 t ha-1. However rainfall variation and land management, especially livestock density, produce changes in soil cover. With low to moderate livestock densities and during prolonged periods with low rainfall (droughts), the vegetation cover may be strongly reduced, provoking high soil losses, whereas during normal or humid periods interrill erosion is low. Excessive stocking rates may exacerbate sheetwash, producing severe soil degradation, regardless of rainfall conditions. In

  4. Biotic and abiotic degradation of pesticide Dufulin in soils.

    PubMed

    Wang, Hua Zi; Zuo, Hai Gen; Ding, Ya Juan; Miao, Shan Shan; Jiang, Chen; Yang, Hong

    2014-03-01

    Dufulin is a newly developed antiviral agent (or pesticide) that activates systemic acquired resistance of plants. This pesticide is widely used in China to prevent abroad viral diseases in rice, tobacco and vegetables. In this study, the potential impacts such as soil type, moisture, temperature, and other factors on Dufulin degradation in soil were investigated. Degradation of Dufulin followed the first-order kinetics. The half-life values varied from 2.27 to 150.68 days. The dissipation of Dufulin was greatly affected by soil types, with DT50 (Degradation half time) varying between 17.59, 31.36, and 43.32 days for Eutric Gleysols, Cumulic Anthrosols, and Dystric Regosols, respectively. The elevated moisture accelerated the decay of Dufulin in soil. Degradation of Dufulin increased with temperature and its half-life values ranged from 16.66 to 42.79 days. Sterilization of soils and treatment with H2O2 resulted in a 6- and 8-fold decrease in degradation rates compared to the control, suggesting that Dufulin degradation was largely governed by microbial processes. Under different light spectra, the most effective degradation occurred with 100-W UV light (DT50=2.27 days), followed by 15-W UV light (DT50=8.32 days) and xenon light (DT50=14.26 days). Analysis by liquid chromatography-mass spectroscopy (LC-MS) revealed that 2-amino-4-methylbenzothiazole was one of the major decayed products of Dufulin in soils, suggesting that elimination of diethyl phosphate and 2-fluorobenzaldehyde was most like the degradation pathway of Dufulin in Eutric Gleysols.

  5. Elevated mobility of persistent organic pollutants in the soil of a tropical rainforest.

    PubMed

    Zheng, Qian; Nizzetto, Luca; Liu, Xiang; Borgå, Katrine; Starrfelt, Jostein; Li, Jun; Jiang, Yishan; Liu, Xin; Jones, Kevin C; Zhang, Gan

    2015-04-07

    Semivolatile persistent organic pollutants (POP) are bioaccumulative and toxic contaminants. Their global distribution depends on source distribution, atmospheric transport, degradation, and the exchange with ocean and land surfaces. Forests are crucial terrestrial reservoirs due to the commonly envisaged high capacity of their surface soils to store and immobilize airborne contaminants bound to soil organic matter. Our results show that POPs can be unexpectedly mobile in the soil of a tropical rainforest due to fast litter turnover (leading to rapid POP transfer to the subsoil) and leaching rates exceeding degradation rates especially for more hydrophobic congeners. Co-transport in association with leaching fine particulate and dissolved organic matter appears as a relevant driver of this PCB export. A markedly different distribution pattern is displayed in this soil in comparison to soils of colder environments with lower overall storage capacity. These findings show that biogeochemistry of organic matter degradation and weathering can influence POP soil fate. Because tropical forests represent 60% of the global terrestrial productivity, the highlighted dynamics might have an implication for the general distribution of these contaminants.

  6. Assessment of imidacloprid degradation by soil-isolated Bacillus alkalinitrilicus.

    PubMed

    Sharma, Smriti; Singh, Balwinder; Gupta, V K

    2014-11-01

    Imidacloprid is extensively used on a broad range of crops worldwide as seed dressing, soil treatment, and foliar application. Hence, the degradation potential of bacterial strains from sugarcane-growing soils was studied in liquid medium for subsequent use in bioremediation of contaminated soils. The microbe cultures degrading imidacloprid were isolated and enriched on Dorn's broth containing imidacloprid as sole carbon source maintained at 28 °C and Bacillus alkalinitrilicus showed maximum potential to degrade imidacloprid. Clay loam soil samples were fortified with imidacloprid at 50, 100, and 150 mg kg(-1) along with 45 × 10(7) microbe cells under two opposing sets of conditions, viz., autoclaved and unautoclaved. To study degradation and metabolism of imidacloprid under these two conditions, samples were drawn at regular intervals of 7, 14, 28, 35, 42, 49, and 56 days. Among metabolites, three metabolites were detected, viz., 6-chloronicotinic acid, nitrosimine followed by imidacloprid-NTG under both the conditions. Total imidacloprid residues were not found to follow the first-order kinetics in both types of conditions. This paper reports for the first time the potential use of pure cultures of soil-isolated native bacterium B. alkalinitrilicus and also its use along with natural soil microflora for remediation of imidacloprid-contaminated soils.

  7. Paraquat adsorption, degradation, and remobilization in tropical soils of Thailand.

    PubMed

    Amondham, Wapakorn; Parkpian, Preeda; Polprasert, Chongrak; DeLaune, R D; Jugsujinda, Aroon

    2006-01-01

    Paraquat adsorption, degradation, and remobilization were investigated in representative tropical soils of Yom River Basin, Thailand. Adsorption of paraquat in eight soil samples using batch equilibration techniques indicated that adsorption depended on soil characteristics, including exchangeable basic cations and iron content. Multiple regression analysis indicated significant contribution of exchangeable calcium percentage (ECP), total iron content (TFe) and exchangeable sodium percentage (ESP) to paraquat sorption (Q). ESP and TFe were significant at all adsorption stages, whereas ESP was significant only at the initial stage of paraquat adsorption. Adsorption studies using two soils representing clay and sandy loam textures showed that paraquat adsorption followed the Freundlich model, exhibiting a nonlinear sorption curve. Paraquat adsorption was higher in the clay soil compared to the sandy loam soil with Kf values of 787 and 18, respectively. Desorption was low with 0.04 to 0.17% and 0.80 to 5.83% desorbed in clay and sandy loam soil, respectively, indicating some hysteresis effect. Time-dependent paraquat adsorption fitted to the Elovich kinetic model indicated that diffusion was a rate-limiting process. Paraquat mobility and degradation studies conducted using both field and laboratory soil column experiments with clay soil showed low mobility of paraquat with accumulation only in the surface 0-5 cm layer under field conditions and in the 0-1 cm layer in a laboratory soil column experiment. Degradation of paraquat in soil was faster under field conditions than at ambient laboratory conditions. The degradation rate followed a first-order kinetic model with the DT50 at 36-46 days and DT90 around 119-152 days.

  8. Exposure scenarios and guidance values for urban soil pollutants.

    PubMed

    Boyd, H B; Pedersen, F; Cohr, K H; Damborg, A; Jakobsen, B M; Kristensen, P; Samsøe-Petersen, L

    1999-12-01

    In general, risk assessments of urban soil pollution are prepared by comparing the levels of pollutants with soil quality criteria. However, large urban areas are contaminated with concentrations of pollutants far exceeding the existing soil quality criteria and would consequently be considered to be of potential risk to humans. This is, however, a rather rigid approach, and for risk management purposes it would be desirable to have more than just one level of soil quality criteria. Therefore, a generic risk assessment model was developed for five different use scenarios: child-care centers, kitchen gardens, ornamental gardens, parks, and sports grounds. In each of the scenarios, three different types of expected behavior are described for children and adults, respectively, resulting in different levels of exposure to the pollutants. For risk management purposes, various guidance values can then be derived for each use scenario. Below a lower guidance value, a free use of the area according to the defined use is possible without an unacceptable risk to the public. Above an upper value, a cutoff of the exposure is necessary. In between, the use may be regulated by different types of advice. The model is still preliminary but was, however, used for derivation of guidance values for five commonly found soil pollutants, of which the results for benzo[a]pyrene and lead are presented.

  9. Facilitating the afforestation of Mediterranean polluted soils by nurse shrubs.

    PubMed

    Domínguez, María T; Pérez-Ramos, Ignacio M; Murillo, José M; Marañón, Teodoro

    2015-09-15

    The revegetation of polluted sites and abandoned agricultural soils is critical to reduce soil losses and to control the spread of soil pollution in the Mediterranean region, which is currently exposed to the greatest soil erosion risk in Europe. However, events of massive plant mortality usually occur during the first years after planting, mainly due to the adverse conditions of high irradiance and drought stress. Here, we evaluated the usefulness of considering the positive plant-plant interactions (facilitation effect) in the afforestation of polluted agricultural sites, using pre-existing shrubs as nurse plants. We used nurse shrubs as planting microsites for acorns of Quercus ilex (Holm oak) along a gradient of soil pollution in southwestern Spain, and monitored seedling growth, survival, and chemical composition during three consecutive years. Seedling survival greatly increased (from 20% to more than 50%) when acorns were sown under shrub, in comparison to the open, unprotected matrix. Facilitation of seedling growth by shrubs increased along the gradient of soil pollution, in agreement with the stress gradient hypothesis that predicts higher intensity of the facilitation effects with increasing abiotic stress. Although the accumulation of trace elements in seedling leaves was higher underneath shrub, the shading conditions provided by the shrub canopy allowed seedlings to cope with the toxicity provoked by the concurrence of low pH and high trace element concentrations in the most polluted sites. Our results show that the use of shrubs as nurse plants is a promising tool for the cost-effective afforestation of polluted lands under Mediterranean conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Isolation and characterisation of azoxystrobin degrading bacteria from soil.

    PubMed

    Howell, Christopher C; Semple, Kirk T; Bending, Gary D

    2014-01-01

    The first strobilurin fungicides were introduced in 1996, and have since been used in a vast array of disease/plant systems worldwide. The strobilurins now consist of 16 compounds and represent the 2nd most important fungicide group worldwide with 15% of the total fungicide market share. Strobilurins are moderately persistent in soil, and some degradation products (e.g. azoxystrobin acid) have been detected as contaminants of freshwater systems. Little is currently known about the transformation processes involved in the biodegradation of strobilurins or the microbial groups involved. Using sequential soil and liquid culture enrichments, we isolated two bacterial strains which were able to degrade the most widely used strobilurin, azoxystrobin, when supplied as a sole carbon source. 16S rRNA showed that the strains showed homology to Cupriavidus sp. and Rhodanobacter sp. Both isolated strains were also able to degrade the related strobilurin compounds trifloxystrobin, pyraclostrobin, and kresoxim-methyl. An additional nitrogen source was required for degradation to occur, but the addition of a further carbon source reduced compound degradation by approximately 50%. However, (14)C radiometric analysis showed that full mineralisation of azosxystrobin to (14)CO2 was negligible for both isolates. 16S rRNA T-RFLP analysis using both DNA and RNA extracts showed that degradation of azoxystrobin in soil was associated with shifts in bacterial community structure. However, the phylotypes which proliferated during degradation could not be attributed to the isolated degraders.

  11. Cleanup of contaminated soil -- Unreal risk assumptions: Contaminant degradation

    SciTech Connect

    Schiffman, A.

    1995-12-31

    Exposure assessments for development of risk-based soil cleanup standards or criteria assume that contaminant mass in soil is infinite and conservative (constant concentration). This assumption is not real for most organic chemicals. Contaminant mass is lost from soil and ground water when organic chemicals degrade. Factors to correct for chemical mass lost by degradation are derived from first-order kinetics for 85 organic chemicals commonly listed by USEPA and state agencies. Soil cleanup criteria, based on constant concentration, are then corrected for contaminant mass lost. For many chemicals, accounting for mass lost yields large correction factors to risk-based soil concentrations. For degradation in ground water and soil, correction factors range from greater than one to several orders of magnitude. The long exposure durations normally used in exposure assessments (25 to 70 years) result in large correction factors to standards even for carcinogenic chemicals with long half-lives. For the ground water pathway, a typical soil criterion for TCE of 1 mg/kg would be corrected to 11 mg/kg. For noncarcinogens, correcting for mass lost means that risk algorithms used to set soil cleanup requirements are inapplicable for many chemicals, especially for long periods of exposure.

  12. Simulation of the migration and transformation of petroleum pollutants in the soils of the Loess plateau: a case study in the Maling oil field of northwestern China.

    PubMed

    Pan, Feng; Ma, Jinzhu; Wang, Yunquan; Zhang, Yali; Chen, Lihua; Edmunds, W Mike

    2013-10-01

    We developed a coupled water-oil simulation model to simulate the migration and transformation of petroleum-derived contaminants in the soil of the Xifeng oil field. To do so, we used the HYDRUS-2D model, which simulates the diffusion, adsorption or desorption, and microbial degradation of petroleum-derived hydrocarbons in the soil-water system. The saturated soil hydraulic conductivity of petroleum-derived pollutants was 0.05 cm day(-1), which is about 1 to 2 % of the soil moisture permeability coefficient. Our numerical simulation results show that spilled crude oil was mainly concentrated in the surface horizons of the soil. The organic pollutant concentration tended to be highest nearest to the pollution source. The pollutant migration was generally concentrated within the top 20 to 30 cm of the soil, with the maximum concentration in the top 5 cm of the soil. With passing time, the pollutant accumulation increased and the adsorption and degradation functions reached a dynamic balance with the input rate at depths greater than 30 cm below the soil surface. The oil-derived pollutants totaled 50 to 100 mg kg(-1) under the dynamic balance condition, which occurred after 20 to 30 years. The petroleum-derived pollutant concentration in the loess soil was inversely correlated with the horizontal distance from the oil well, and the concentration decreased greatly at a distance greater than 40 m from the well.

  13. Desertification, Land Degradation and the restoration of soil functions

    NASA Astrophysics Data System (ADS)

    Imeson, A.

    2012-04-01

    Soil science and soil scientists have and are playing different roles in desertification. Research has shown that the main drivers of land degradation are unsustainable preactices of agricultre and indusrty or of forest clearanc. If we look at soil conservation and soil protection, this is mainly in the service of agriculture and development. The LEDDRA project is looking at different paradigms of land degradation that could be used to identify emergent benefits and constraints that could lead to people adopting and favouring activitis that lead to the restoration of land and soil functions. The second part of the paper will discuss how soil process knowledge can be applied to restore the hydrological function of soils and produce economic benefits by reduced flooding and soil loss. The third part of the paper will introduce the Agriscape strategy which aims to improve the productivity of soils in differeent environments and setting by improving their moisture and temperature conditions. Finally, the opportunities for large scale geoengineering approaches will be proposed that include things such as altering the evaporative losses and restoring groundwater levels in arid areas. A global programme of soil and forest restoration could be undertaken restoring and creating terraces creating agricultural land and water, which has additional benefits too crops. The loss of the supporting functions of the earth could be impaired if there is no global governance of the land and water.

  14. Geostatistical Microscale Study of Magnetic Susceptibility in Soil Profile and Magnetic Indicators of Potential Soil Pollution.

    PubMed

    Zawadzki, Jarosław; Fabijańczyk, Piotr; Magiera, Tadeusz; Rachwał, Marzena

    Directional variograms, along the soil profile, can be useful and precise tool that can be used to increase the precision of the assessment of soil pollution. The detail analysis of spatial variability in the soil profile can be also an important part of the standardization of soil magnetometry as a screening method for an assessment of soil pollution related to the dust deposition. The goal of this study was to investigate the correlation between basic parameters of spatial correlations of magnetic susceptibility in the soil profile, such as a range of correlation and a sill, and selected magnetometric indicators of soil pollution. Magnetic indicators were an area under the curve of magnetic susceptibility versus a depth in the soil profile, values of magnetic susceptibility at depths ranging from 1 to 10 cm, and maximum and background values of magnetic susceptibility in the soil profile. These indicators were previously analyzed in the literature. The results showed that a range of correlation of magnetic susceptibility was significantly correlated with magnetic susceptibility measured at depths 1, 2, and 3 cm. It suggests that a range of correlation is a good measure of pollutants' dispersion in the soil profile. The sill of the variogram of magnetic susceptibility was found to be significantly correlated with the area under the curve of plot of magnetic susceptibility that is related to the soil pollution. In consequence, the parameters of microscale spatial variability of magnetic susceptibility in s soil profile are important measures that take into consideration the spatial aspect of s soil pollution.

  15. Ion activity and distribution of heavy metals in acid mine drainage polluted subtropical soils.

    PubMed

    Li, Yong-Tao; Becquer, Thierry; Dai, Jun; Quantin, Cécile; Benedetti, Marc F

    2009-04-01

    The oxidative dissolution of mine wastes gives rise to acidic, metal-enriched mine drainage (AMD) and has typically posed an additional risk to the environment. The poly-metallic mine Dabaoshan in South China is an excellent test site to understand the processes affecting the surrounding polluted agricultural fields. Our objectives were firstly to investigate metal ion activity in soil solution, distribution in solid constituents, and spatial distribution in samples, secondly to determine dominant environment factors controlling metal activity in the long-term AMD-polluted subtropical soils. Soil Column Donnan Membrane Technology (SC-DMT) combined with sequential extraction shows that unusually large proportion of the metal ions are present as free ion in the soil solutions. The narrow range of low pH values prevents any pH effects during the binding onto oxides or organic matter. The differences in speciation of the soil solutions may explain the different soil degradation observed between paddy and non-paddy soils.

  16. The degradation characteristics of microbial biomass in soil

    NASA Astrophysics Data System (ADS)

    Spence, Adrian; Simpson, Andre J.; Mcnally, David J.; Moran, Brian W.; McCaul, Margaret V.; Hart, Kris; Paull, Brett; Kelleher, Brian P.

    2011-05-01

    Soil microbial biomass is a primary source of soil organic carbon (SOC) and therefore plays a fundamental role in carbon and nitrogen cycling. However, little is known about the fate and transformations of microbial biomass in soil. Here we employ HR-MAS NMR spectroscopy to monitor 13C and 15N labeled soil microbial biomass and leachate degradation over time. As expected, there is a rapid loss of carbohydrate structures. However, diffusion edited HR-MAS NMR data reveals that macromolecular carbohydrates are more resistant to degradation and are found in the leachate. Aromatic components survive as dissolved species in the leachate while aliphatic components persist in both the biomass and leachate. Dissolved protein and peptidoglycan accumulate in the leachate and recalcitrant amide nitrogen and lipoprotein persists in both the degraded biomass and leachate. Cross-peaks that appear in 1H- 15N HR-MAS NMR spectra after degradation suggest that specific peptides are either selectively preserved or used for the synthesis of unknown structures. The overall degradation pathways reported here are similar to that of decomposing plant material degraded under similar conditions suggesting that the difference between recalcitrant carbon from different sources is negligible after decomposition.

  17. Enhanced degradation of spiro-insecticides and their leacher enol derivatives in soil by solarization and biosolarization techniques.

    PubMed

    Fenoll, José; Garrido, Isabel; Vela, Nuria; Ros, Caridad; Navarro, Simón

    2017-04-01

    The leaching potential of three insecticides (spirodiclofen, spiromesifen, and spirotetramat) was assessed using disturbed soil columns. Small quantities of spirodiclofen and spiromesifen were detected in leachate fraction, while spirotetramat residues were not found in the leachates. In addition, the transformation products (enol derivatives) are relatively more mobile than the parent compounds and may leach into groundwater. Moreover, the use of disinfection soil techniques (solarization and biosolarization) to enhance their degradation rates in soil was investigated. The results show that both practices achieved a reduction in the number of juvenile nematodes, enhancing in a parallel way degradation rates of the insecticides and their enol derivatives as compared with the non-disinfected soil. This behavior can be mainly attributed to the increase in soil temperature and changes in microbial activity. All insecticides showed similar behavior under solarization and biosolarization conditions. As a consequence, both agronomic techniques could be considered as suitable strategies for detoxification of soils polluted with the studied pesticides.

  18. Magnetic properties of alluvial soils polluted with heavy metals

    NASA Astrophysics Data System (ADS)

    Dlouha, S.; Petrovsky, E.; Boruvka, L.; Kapicka, A.; Grison, H.

    2012-04-01

    Magnetic properties of soils, reflecting mineralogy, concentration and grain-size distribution of Fe-oxides, proved to be useful tool in assessing the soil properties in terms of various environmental conditions. Measurement of soil magnetic properties presents a convenient method to investigate the natural environmental changes in soils as well as the anthropogenic pollution of soils with several risk elements. The effect of fluvial pollution with Cd, Cu, Pb and Zn on magnetic soil properties was studied on highly contaminated alluvial soils from the mining/smelting district (Příbram; CZ) using a combination of magnetic and geochemical methods. The basic soil characteristics, the content of heavy metals, oxalate, and dithionite extractable iron were determined in selected soil samples. Soil profiles were sampled using HUMAX soil corer and the magnetic susceptibility was measured in situ, further detailed magnetic analyses of selected distinct layers were carried out. Two types of variations of magnetic properties in soil profiles were observed corresponding to indentified soil types (Fluvisols, and Gleyic Fluvisols). Significantly higher values of topsoil magnetic susceptibility compared to underlying soil are accompanied with high concentration of heavy metals. Sequential extraction analysis proved the binding of Pb, Zn and Cd in Fe and Mn oxides. Concentration and size-dependent parameters (anhysteretic and isothermal magnetization) were measured on bulk samples in terms of assessing the origin of magnetic components. The results enabled to distinguish clearly topsoil layers enhanced with heavy metals from subsoil samples. The dominance of particles with pseudo-single domain behavior in topsoil and paramagnetic/antiferromagnetic contribution in subsoil were observed. These measurements were verified with room temperature hysteresis measurement carried out on bulk samples and magnetic extracts. Thermomagnetic analysis of magnetic susceptibility measured on

  19. Application of System Dynamics technique to simulate the fate of persistent organic pollutants in soils.

    PubMed

    Chaves, R; López, D; Macías, F; Casares, J; Monterroso, C

    2013-03-01

    Persistent organic pollutants (POPs) are within the most dangerous pollutants released into the environment by human activities. Due to their resistance to degradation (chemical, biological or photolytic), it is critical to assess the fate and environmental hazards of the exchange of POPs between different environmental media. System Dynamics enables to represent complex systems and analyze their dynamic behavior. It provides a highly visual representation of the structure of the system and the existing relationships between the several parameters and variables, facilitating the understanding of the behavior of the system. In the present study the fate of γ-hexachlorocyclohexane (lindane) in a contaminated soil was modeled using the Vensim® simulation software. Results show a gradual decrease in the lindane content in the soil during a simulation period of 10 years. The most important route affecting the concentrations of the contaminant was the biochemical degradation, followed by infiltration and hydrodynamic dispersion. The model appeared to be highly sensitive to the half-life of the pollutant, which value depends on environmental conditions and directly affects the biochemical degradation.

  20. Diffuse pollution of soil and water: Long term trends at large scales?

    NASA Astrophysics Data System (ADS)

    Grathwohl, P.

    2012-04-01

    Industrialization and urbanization, which consequently increased pressure on the environment to cause degradation of soil and water quality over more than a century, is still ongoing. The number of potential environmental contaminants detected in surface and groundwater is continuously increasing; from classical industrial and agricultural chemicals, to flame retardants, pharmaceuticals, and personal care products. While point sources of pollution can be managed in principle, diffuse pollution is only reversible at very long time scales if at all. Compounds which were phased out many decades ago such as PCBs or DDT are still abundant in soils, sediments and biota. How diffuse pollution is processed at large scales in space (e.g. catchments) and time (centuries) is unknown. The relevance to the field of processes well investigated at the laboratory scale (e.g. sorption/desorption and (bio)degradation kinetics) is not clear. Transport of compounds is often coupled to the water cycle and in order to assess trends in diffuse pollution, detailed knowledge about the hydrology and the solute fluxes at the catchment scale is required (e.g. input/output fluxes, transformation rates at the field scale). This is also a prerequisite in assessing management options for reversal of adverse trends.

  1. Water pollution and habitat degradation in the Gulf of Thailand.

    PubMed

    Cheevaporn, Voravit; Menasveta, Piamsak

    2003-01-01

    The Gulf of Thailand has been a major marine resource for Thai people for a long time. However, recent industrialization and community development have exerted considerable stress on the marine environments and provoked habitat degradation. The following pollution problems in the Gulf have been prioritized and are discussed in details: (1) Untreated municipal and industrial waste water are considered to be the most serious problems of the country due to limited waste water treatment facilities in the area. (2) Eutrophication is an emerging problem in the gulf of Thailand. Fortunately, the major species of phytoplankton that have been reported as the cause of red tide phenomena were non-toxic species such as Noctiluca sp. and Trichodesmium sp. (3) Few problems have been documented from trace metals contamination in the Gulf of Thailand and public health threat from seafood contamination does not appear to be significant yet. (4) Petroleum hydrocarbon residue contamination is not a problem, although a few spills from small oil tankers have been recorded. A rapid decrease in mangrove forest, coral reefs, and fisheries resources due to mismanagement is also discussed.

  2. Bioremediation of engine oil polluted soil by the tropical white rot fungus, Lentinus squarrosulus Mont. (Singer).

    PubMed

    Adenipekun, Clementina O; Isikhuemhen, Omoanghe S

    2008-06-15

    This study was conducted to test the efficacy of an indigenous white rot fungus Lentinus squarrosulus in degrading engine oil in soil. Flasks containing sterilized garden soil (100 g) moistened with 75% distilled water (w/v) were contaminated with engine oil 1, 2.5, 5, 10, 20 and 40% w/w concentrations, inoculated with L. squarrosulus and incubated at room temperature for 90 days. Levels of organic matter, pH, total hydrocarbon and elemental content (C, Cu, Fe, K, N, Ni, Zn and available P) were determined post-fungal treatment. Results indicate that contaminated soils inoculated with L. squarrosulus had increased organic matter, carbon and available phosphorus, while the nitrogen and available potassium was reduced. A relatively high percentage degradation of Total Petroleum Hydrocarbon (TPH) was observed at 1% engine oil concentration (94.46%), which decreased to 64.05% TPH degradation at 40% engine oil contaminated soil after 90 days of incubation. The concentrations of Fe, Cu, Zn and Ni recovered from straw/fungal biomass complex increased with the increase of engine-oil contamination and bio-accumulation by the white-rot fungus. The improvement of nutrient content values as well as the bioaccumulation of heavy metals at all levels of engine oil concentrations tested through inoculations with L. squarrosulus is of importance for the bioremediation of engine-oil polluted soils.

  3. Surfactant remediation of diesel fuel polluted soil.

    PubMed

    Khalladi, Razika; Benhabiles, Ouassila; Bentahar, Fatiha; Moulai-Mostefa, Naji

    2009-05-30

    Soil contamination with petroleum hydrocarbons has caused critical environmental and health defects and increasing attention has been paid for developing innovative technology for cleaning up this contamination. In this work, the washing process of a soil column by ionic surfactant sodium dodecyl sulfate (SDS) was investigated. Water flow rate and the contamination duration (age) have been studied. The performance of water in the removal of diesel fuel was found to be non-negligible, while water contributed by 24.7% in the global elimination of n-alkanes. The effect of SDS is significant beyond a concentration of 8mM. After 4h of treatment with surfactant solution, the diesel soil content remains constant, which shows the existence of a necessary contact time needed to the surfactant to be efficient. The soil washing process at a rate of 3.2 mL/min has removed 97% of the diesel fuel. This surfactant soil remediation process was shown to be governed by the first-order kinetics. These results are of practical interest in developing effective surfactant remediation technology of diesel fuel contaminated soils.

  4. [Assessment of Soil Fluorine Pollution in Jinhua Fluorite Ore Areas].

    PubMed

    Ye, Qun-feng; Zhou, Xiao-ling

    2015-07-01

    The contents of. soil total fluorine (TF) and water-soluble fluorine (WF) were measured in fluorite ore areas located in Jinhua City. The single factor index, geoaccumulation index and health risk assessment were used to evaluate fluorine pollution in soil in four fluorite ore areas and one non-ore area, respectively. The results showed that the TF contents in soils were 28. 36-56 052. 39 mg.kg-1 with an arithmetic mean value of 8 325.90 mg.kg-1, a geometric mean of 1 555. 94 mg.kg-1, and a median of 812. 98 mg.kg-1. The variation coefficient of TF was 172. 07% . The soil WF contents ranged from 0. 83 to 74. 63 mg.kg-1 with an arithmetic mean value of 16. 94 mg.kg-1, a geometric mean of 10. 59 mg.kg-1, and a median of 10. 17 mg.kg-1. The variation coefficient of WF was 100. 10%. The soil TF and WF contents were far higher than the national average level of the local fluorine epidemic occurrence area. The fluoride pollution in soil was significantly affected by human factors. Soil fluorine pollution in Yangjia, Lengshuikeng and Huajie fluorite ore areas was the most serious, followed by Daren fluorite ore area, and in non-ore area there was almost no fluorine pollution. Oral ingestion of soils was the main exposure route. Sensitivity analysis of model parameters showed that children's weight exerted the largest influence over hazard quotient. Furthermore, a significant positive correlation was found among the three kinds of evaluation methods.

  5. Thermal properties of degraded lowland peat-moorsh soils

    NASA Astrophysics Data System (ADS)

    Gnatowski, Tomasz

    2016-04-01

    Soil thermal properties, i.e.: specific heat capacity (c), thermal conductivity (K), volumetric heat capacity (C) govern the thermal environment and heat transport through the soil. Hence the precise knowledge and accurate predictions of these properties for peaty soils with high amount of organic matter are especially important for the proper forecasting of soil temperature and thus it may lead to a better assessment of the greenhouse gas emissions created by microbiological activity of the peatlands. The objective of the study was to develop the predictive models of the selected thermal parameters of peat-moorsh soils in terms of their potential applicability for forecasting changes of soil temperature in degraded ecosystems of the Middle Biebrza River Valley area. Evaluation of the soil thermal properties was conducted for the parameters: specific heat capacity (c), volumetric heat capacities of the dry and saturated soil (Cdry, Csat) and thermal conductivities of the dry and saturated soil (Kdry, Ksat). The thermal parameters were measured using the dual-needle probe (KD2-Pro) on soil samples collected from seven peaty soils, representing total 24 horizons. The surface layers were characterized by different degrees of advancement of soil degradation dependent on intensiveness of the cultivation practises (peaty and humic moorsh). The underlying soil layers contain peat deposits of different botanical composition (peat-moss, sedge-reed, reed and alder) and varying degrees of decomposition of the organic matter, from H1 to H7 (von Post scale). Based on the research results it has been shown that the specific heat capacity of the soils differs depending on the type of soil (type of moorsh and type of peat). The range of changes varied from 1276 J.kg-1.K-1 in the humic moorsh soil to 1944 J.kg-1.K-1 in the low decomposed sedge-moss peat. It has also been stated that in degraded peat soils with the increasing of the ash content in the soil the value of specific heat

  6. Adsorption and degradation of five selected antibiotics in agricultural soil.

    PubMed

    Pan, Min; Chu, L M

    2016-03-01

    Large quantities of antibiotics are being added to agricultural fields worldwide through the application of wastewater, manures and biosolids, resulting in antibiotic contamination and elevated environmental risks in terrestrial environments. Most studies on the environmental fate of antibiotics focus on aquatic environments or wastewater treatment plants. Little is known about the behavior of antibiotics at environmentally relevant concentrations in agricultural soil. In this study we evaluated the adsorption and degradation of five different antibiotics (tetracycline, sulfamethazine, norfloxacin, erythromycin, and chloramphenicol) in sterilized and non-sterilized agricultural soils under aerobic and anaerobic conditions. Adsorption was highest for tetracycline (Kd, 1093 L/kg), while that for sulfamethazine was negligible (Kd, 1.365 L/kg). All five antibiotics were susceptible to microbial degradation under aerobic conditions, with half-lives ranging from 2.9 to 43.3 d in non-sterilized soil and 40.8 to 86.6 d in sterilized soil. Degradation occurred at a higher rate under aerobic conditions but was relatively persistent under anaerobic conditions. For all the antibiotics, a higher initial concentration was found to slow down degradation and prolong persistence in soil. The degradation behavior of the antibiotics varied in relation to their physicochemical properties as well as the microbial activities and aeration of the recipient soil. The poor adsorption and relative persistence of sulfamethazine under both aerobic and anaerobic conditions suggest that it may pose a higher risk to groundwater quality. An equation was proposed to predict the fate of antibiotics in soil under different field conditions, and assess their risks to the environment.

  7. No long-term persistence of bacterial pollution-induced community tolerance in tylosin-polluted soil.

    PubMed

    Demoling, Louise Aldén; Bååth, Erland

    2008-09-15

    Pollution-induced community tolerance (PICT) of soil bacteria to the antibiotic tylosin was studied over 95 days. Tylosin was added at increasing concentrations, together with different amounts of alfalfa to study the effects of substrate addition on PICT and bacterial growth in soil. The leucine incorporation technique was used to estimate bacterial growth and as a detection method in the PICT concept. Direct inhibition of the bacterial growth rates, resulting in a dose-response curve, was found above 50 mg of tylosin kg(-1) of soil two days after tylosin addition (IC50 value of 960 mg tylosin kg(-1)). After 10 days of exposure to at least 50 mg of tylosin kg(-1), the PICT was observed and correlated to inhibition of bacterial growth by tylosin. A return of the PICT to control levels was found over time, and after 95 days at 1500 mg of tylosin kg(-1), essentially no PICT was found, as compared to the unpolluted control soil. The return of PICT to pre-exposure levels was not totally reflected in the recovery of bacterial growth. Alfalfa addition did not affect the inhibitory effect of tylosin on bacterial growth rates; neither did it alter the PICT. Since tylosin is relatively rapidly degraded in soil, our results indicate that the PICT will return to prepollution levels when the selective pressure of the toxicant is removed and will thus be a useful technique for monitoring remediation measures.

  8. Influence of soil moisture on sorption and degradation of hexazinone and simazine in soil.

    PubMed

    García-Valcárcel, A I; Tadeo, J L

    1999-09-01

    Sorption and degradation rates of hexazinone and simazine on soil were determined in a sandy loam soil incubated, during 44 days, at 25 degrees C with moisture contents ranging from 4% to 18%. Herbicide levels in soil solution were also measured, after extraction of this solution by a centrifugation method. All experiments were conducted with treated soil in plastic columns, and the results showed that this method is suitable for the simultaneous study of pesticide sorption and degradation in soil at different environmental conditions. In general, sorption of both herbicides was higher for aged herbicide residues compared to recently applied herbicides, and soil subjected to drying and rewetting cycles had the highest sorption values. K(f) values ranged from 0.5 to 1.2 for simazine and from 0.2 to 0.4 for hexazinone. Degradation rates increased with soil moisture content for both herbicides, and drying-rewetting of soil yielded degradation rates slower than that obtained at 10% soil moisture content. Hexazinone concentration in soil solution decreased with incubation time faster than simazine.

  9. Soil microbial response to photo-degraded C60 fullerenes.

    PubMed

    Berry, Timothy D; Clavijo, Andrea P; Zhao, Yingcan; Jafvert, Chad T; Turco, Ronald F; Filley, Timothy R

    2016-04-01

    Recent studies indicate that while unfunctionalized carbon nanomaterials (CNMs) exhibit very low decomposition rates in soils, even minor surface functionalization (e.g., as a result of photochemical weathering) may accelerate microbial decay. We present results from a C60 fullerene-soil incubation study designed to investigate the potential links between photochemical and microbial degradation of photo-irradiated C60. Irradiating aqueous (13)C-labeled C60 with solar-wavelength light resulted in a complex mixture of intermediate products with decreased aromaticity. Although addition of irradiated C60 to soil microcosms had little effect on net soil respiration, excess (13)C in the respired CO2 demonstrates that photo-irradiating C60 enhanced its degradation in soil, with ∼ 0.78% of 60 day photo-irradiated C60 mineralized. Community analysis by DGGE found that soil microbial community structure was altered and depended on the photo-treatment duration. These findings demonstrate how abiotic and biotic transformation processes can couple to influence degradation of CNMs in the natural environment.

  10. Control of the pollution of antibiotic resistance genes in soils by quorum sensing inhibition.

    PubMed

    Lai, Bai-Min; Zhang, Kun; Shen, Dong-Sheng; Wang, Mei-Zhen; Shentu, Jia-Li; Li, Na

    2017-02-01

    To investigate whether pollution from antibiotic resistance genes (ARGs) could be affected by bacterial quorum sensing, the oxytetracycline (OTC)-containing manure was fertilized to establish the ARG-polluted soil environment. Under long-term OTC stress, substantial ARGs in the range from 10(-4) to 10(-3) RG/16S rRNA (resistance genes/16S rRNA) were detected in the antibiotics control (AC) group, in which OTC-containing manure was fertilized. Meanwhile, 10(-6) RG/16S rRNA was detected in biological control (BC) group, in which non-OTC-containing manure was fertilized. Subsequently, two typical quorum sensing inhibitors, 4-nitropyridine N-oxide (4-NPO) and 3,4-dibromo-2H-furan-5-one (DBF), were used to treat the ARG-polluted soils. These two groups called 4-NPO treatments (NT) and DBF treatments (FT), respectively. There were no significant differences in bacterial growth and OTC degradation in NT and FT groups, compared to AC group. However, acyl-homoserine lactones such as C4-HSL, C6-HSL, and C8-HSL decreased significantly in both NT and FT groups, compared to AC group. Meanwhile, the abundance of most ARGs decreased dramatically. In FT group, the concentrations of tet(L) and tet(Q) were below the detection limits. It was demonstrated that quorum sensing inhibition could be an effective way to prevent and control the pollution of ARGs in soil.

  11. Measurement of Bioaccessibility of Organic Pollutants in Soil

    NASA Astrophysics Data System (ADS)

    McAllister, Laura; Semple, Kirk T.

    The quantification of organic contaminant bioaccessibility in soils and sediments is essential for the risk assessment and remediation of contaminated land. Within this framework, practitioners require standardised protocols. Cyclodextrins are a group of macrocyclic compounds that can form inclusion complexes with organic xenobiotics. This occurrence can be exploited to measure the labile/rapidly desorbable compound fraction, which correlates with microbial degradation. We present a rapid and easily reproducible HPCD shake extraction technique that has been experimentally demonstrated to directly predict microbial availability and degradation in soil. This method can provide practitioners with both an indication of bioremediation end-points and may be valuable in the risk assessment of contaminated land.

  12. Ecological effects of combined pollution associated with e-waste recycling on the composition and diversity of soil microbial communities.

    PubMed

    Liu, Jun; He, Xiao-Xin; Lin, Xue-Rui; Chen, Wen-Ce; Zhou, Qi-Xing; Shu, Wen-Sheng; Huang, Li-Nan

    2015-06-02

    The crude processing of electronic waste (e-waste) has led to serious contamination in soils. While microorganisms may play a key role in remediation of the contaminated soils, the ecological effects of combined pollution (heavy metals, polychlorinated biphenyls, and polybrominated diphenyl ethers) on the composition and diversity of microbial communities remain unknown. In this study, a suite of e-waste contaminated soils were collected from Guiyu, China, and the indigenous microbial assemblages were profiled by 16S rRNA high-throughput sequencing and clone library analysis. Our data revealed significant differences in microbial taxonomic composition between the contaminated and the reference soils, with Proteobacteria, Acidobacteria, Bacteroidetes, and Firmicutes dominating the e-waste-affected communities. Genera previously identified as organic pollutants-degrading bacteria, such as Acinetobacter, Pseudomonas, and Alcanivorax, were frequently detected. Canonical correspondence analysis revealed that approximately 70% of the observed variation in microbial assemblages in the contaminated soils was explained by eight environmental variables (including soil physiochemical parameters and organic pollutants) together, among which moisture content, decabromodiphenyl ether (BDE-209), and copper were the major factors. These results provide the first detailed phylogenetic look at the microbial communities in e-waste contaminated soils, demonstrating that the complex combined pollution resulting from improper e-waste recycling may significantly alter soil microbiota.

  13. Removal of PAHs and pesticides from polluted soils by enhanced electrokinetic-Fenton treatment.

    PubMed

    Bocos, Elvira; Fernández-Costas, Carmen; Pazos, Marta; Sanromán, M Ángeles

    2015-04-01

    In this study, electrokinetic-Fenton treatment was used to remediate a soil polluted with PAHs and the pesticide pyrimethanil. Recently, this treatment has emerged as an interesting alternative to conventional soil treatments due to its peculiar advantages, namely the capability of treating fine and low-permeability materials, as well as that of achieving a high yield in the removals of salt content and inorganic and organic pollutants. In a standard electrokinetic-Fenton treatment, the maximum degradation of the pollutant load achieved was 67%, due to the precipitation of the metals near the cathode chamber that reduces the electro-osmotic flow of the system and thus the efficiency of the treatment. To overcome this problem, different complexing agents and pH control in the cathode chamber were evaluated to increase the electro-osmotic flux as well as to render easier the solubilization of the metal species present in the soil. Four complexing agents (ascorbic acid, citric acid, oxalic acid and ethylenediaminetetraacetic acid) in the Fenton-like treatment were evaluated. Results revealed the citric acid as the most suitable complexing agent. Thereby its efficiency was tested as pH controller by flushing it in the cathode chamber (pH 2 and 5). For the latter treatments, near total degradation was achieved after 27 d. Finally, phytotoxicity tests for polluted and treated samples were carried out. The high germination levels of the soil treated under enhanced conditions concluded that nearly complete restoration was achieved. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Travel of pollution, and purification en route, in sandy soils

    PubMed Central

    Baars, J. K.

    1957-01-01

    The travel of pollution in sandy soils, and the extent to which purification takes place en route, are discussed, with special reference to the possible contamination of ground water—a problem which is of particular importance in the Netherlands, where the water-supply for many of the large towns is drawn from the water underneath the dunes. Specifically, two types of soil pollution are considered: (a) severe pollution of the surface layers with matter concentrated in a small volume of water (e.g., faecal matter from pit privies at camping-sites); and (b) moderate pollution of the surface layers with matter contained in large quantities of water (e.g., organic matter and bacteria in river water used for the artificial recharge of ground water). It is shown that in both these types of pollution the self-purification is sufficient to prevent contamination of the ground water, provided that the soil is very fine and—in the case of the first type—dry and well aerated, and provided that the ground-water level is not too high or the rate of infiltration too great. PMID:13472428

  15. Aerobic degradation and photolysis of tylosin in water and soil.

    PubMed

    Hu, Dingfei; Coats, Joel R

    2007-05-01

    Veterinary antibiotics enter the environment through the application of organic fertilizers to cropland. In this study, the aerobic degradation of tylosin, a widely used antibiotic in the production of livestock and poultry, was conducted in water and in soil in an effort to further investigate its environmental fate. Tylosin is a macrolide antibiotic, which consists of four factors (A, B, C, D). Water and soil were sampled at selected times and analyzed for tylosin and its degradation products by high-performance liquid chromatography (HPLC), with product identification confirmed by HPLC-mass spectrometry. Tylosin A is degraded with a half-life of 200 d in the light in water, and the total loss of tylosin A in the dark is 6% of the initial spiked amount during the experimental period. Tylosin C and D are relatively stable except in ultrapure water in the light. Slight increases of tylosin B after two months and formation of two photoreaction isomers of tylosin A were observed under exposure to light. However, tylosin probably would degrade faster if the experimental containers did not prevent ultraviolet transmission. In soil, tylosin A has a dissipation half-life of 7 d, and tylosin D is slightly more stable, with a dissipation half-life of 8 d in unsterilized and sterilized soil. Sorption and abiotic degradation are the major factors influencing the loss of tylosin in the environment, and no biotic degradation was observed at the test concentration either in pond water or in an agronomic soil, as determined by comparing dissipation profiles in sterilized and unsterilized conditions.

  16. Using soil health to assess ecotoxicological impacts of pollutants on soil microflora.

    PubMed

    Bécaert, Valérie; Deschênes, Louise

    2006-01-01

    Microorganisms are essential for a properly functioning soil ecosystem. However, few methods allow an ecotoxicological evaluation of pollutant impact on the soil microbial community. This review proposes the use of the concept of soil health as an ecotoxicological evaluation tool for soil microflora. Initially limited to sustainable agriculture, the concept of soil health is now being applied to novel situations including contaminated and remediated soils. A large amount of work has been published in the last few decades on soil health indicators, and a review of the most relevant studies is presented here. The most cited work is that of the S-5518 committee set up in 1997 by the Soil Science Society of America (SSSA), which proposed to define soil quality as being "the capacity of a soil to function within the limits of an ecosystem, to support biological production, to maintain environmental quality and to support fauna and flora health." The soil health indicators reviewed here are the ones based on this definition because it relates well to sustainability and durability of the soil functions. Several indicators proposed in these studies could be employed in the evaluation of the ecotoxicological impact of pollutants on the soil microbial community, including microbial diversity, microbial activity, and functional stability. However, research is still required to unify the concept, to set threshold values, and to standardize methodologies.

  17. Remediation of electronic waste polluted soil using a combination of persulfate oxidation and chemical washing.

    PubMed

    Chen, Fu; Luo, Zhanbin; Liu, Gangjun; Yang, Yongjun; Zhang, Shaoliang; Ma, Jing

    2017-09-04

    Laboratory experiments were conducted to investigate the efficiency of a simultaneous chemical extraction and oxidation for removing persistent organic pollutants (POPs) and toxic metals from an actual soil polluted by the recycling activity of electronic waste. Various chemicals, including hydroxypropyl-β-cyclodextrin (HPCD), citric acid (CA) and sodium persulfate (SP) were applied synchronously with Fe(2+) activated oxidation to enhance the co-removal of both types of pollutants. It is found that the addition of HPCD can enhance POPs removal through solubilization of POPs and iron chelation; while the CA-chelated Fe(2+) activation process is effective for extracting metals and degrading residual POPs. Under the optimized reagent conditions, 69.4% Cu, 78.1% Pb, 74.6% Ni, 97.1% polychlorinated biphenyls, 93.8% polycyclic aromatic hydrocarbons, and 96.4% polybrominated diphenylethers were removed after the sequential application of SP-HPCD-Fe(2+) and SP-CA-Fe(2+) processes with a duration of 180 and 240 min, respectively. A high dehalogenation efficiency (84.8% bromine and 86.2% chlorine) is observed, suggesting the low accumulation of halogen-containing organic intermediates. The remediated soil can satisfy the national soil quality standard of China. Collectively, co-contaminated soil can be remediated with reasonable time and capital costs through simultaneous application of persulfate oxidation and chemical extraction. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. TNT and RDX degradation and extraction from contaminated soil using subcritical water.

    PubMed

    Islam, Mohammad Nazrul; Shin, Moon-Su; Jo, Young-Tae; Park, Jeong-Hun

    2015-01-01

    The use of explosives either for industrial or military operations have resulted in the environmental pollution, poses ecological and health hazard. In this work, a subcritical water extraction (SCWE) process at laboratory scale was used at varying water temperature (100-175 °C) and flow rate (0.5-1.5 mL min(-1)), to treat 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) contaminated soil, to reveal information with respect to the explosives removal (based on the analyses of soil residue after extraction), and degradation performance (based on the analyses of water extracts) of this process. Continuous flow subcritical water has been considered on removal of explosives to avoid the repartitioning of non-degraded compounds to the soil upon cooling which usually occurs in the batch system. In the SCWE experiments, near complete degradation of both TNT and RDX was observed at 175 °C based on analysis of water extracts and soil. Test results also indicated that TNT removal of >99% and a complete RDX removal were achieved by this process, when the operating conditions were 1 mL min(-1), and treatment time of 20 min, after the temperature reached 175 °C. HPLC-UV and ion chromatography analysis confirmed that the explosives underwent for degradation. The low concentration of explosives found in the process wastewater indicates that water recycling may be viable, to treat additional soil. Our results have shown in the remediation of explosives contaminated soil, the effectiveness of the continuous flow SCWE process.

  19. Remediation of copper polluted red soils with clay materials.

    PubMed

    Zhang, Gangya; Lin, Yunqing; Wang, Mingkuang

    2011-01-01

    Attapulgite and montmorillonite were utilized to remediate heavy metal polluted red soils in Guixi City, Jiangxi Province, China. The effects of clay minerals on availability, chemical distribution, and biotoxicity of Cu and Zn were evaluated. The results provided a reference for the rational application of clay materials to remediate heavy metal contaminated soils. From the sorption experiment, the maximum adsorbed Cu2+ by attapulgite and montmorillonite was 1501 and 3741 mg/kg, respectively. After polluted red soil was amended with attapulgite or montmorillonite and cultured at 30 and 60 days, soil pH increased significantly compared to the control. An 8% increase in the amount of montmorillonite in soil and 30 days incubation decreased acid exchangeable Cu by 24.7% compared to the control red soil. Acid exchangeable Cu decreased with increasing amounts of attapulgite and montmorillonite, with best remediation effect reached at a dose of 8%. Results also showed that the Cu poisoning effect on earthworms was reduced with the addition of attapulgite and montmorillonite. Montmorillonite showed the best effect, with the addition of a 2% dose the mortality of earthworms decreased from 60% to zero compared to the control. Our results indicated that the bioavailability of Cu in soils was reduced more effectively with the application of montmorillonite than attapulgite.

  20. Degradation of oil products in a soil from a Russian Barents hot-spot during electrodialytic remediation.

    PubMed

    Pedersen, Kristine B; Lejon, Tore; Jensen, Pernille E; Ottosen, Lisbeth M

    2016-01-01

    A highly oil-polluted soil from Krasnoe in North-West Russia was used to investigate the degradation of organic pollutants during electrodialytic remediation. Removal efficiencies were up to 70 % for total hydrocarbons (THC) and up to 65 % for polyaromatic hydrocarbons (PAH). Relatively more of the lighter PAH compounds and THC fractions were degraded. A principal component analysis (PCA) revealed a difference in the distribution of PAH compounds after the remediation. The observed clustering of experiments in the PCA scores plot was assessed to be related to the stirring rate. Multivariate analysis of the experimental settings and final concentrations in the 12 experiments revealed that the stirring rate of the soil suspension was by far the most important parameter for the remediation for both THC and PAH. Light was the second most important variable for PAH and seems to influence degradation. The experimental variables current density and remediation time did not significantly influence the degradation of the organic pollutants. Despite current density not influencing the remediation, there is potential for degrading organic pollutants during electrodialytic removal of heavy metals, as long as a stirred set-up is applied. Depending on remediation objectives, further optimisation may be needed in order to develop efficient remediation strategies.

  1. Implications of soil pollution with heavy metals for public health

    NASA Astrophysics Data System (ADS)

    Juozulynas, Algirdas; Jurgelėnas, Antanas; Butkienė, Birutė; Greičiūtė, Kristina; Savičiūtė, Rasa

    2008-01-01

    Soil of military grounds is often polluted with heavy metals. Their concentrations may be dosens of times higher in polluted regions. The affected soils are permeable, so the pollutions can get into water and spread to the environment. Into human and animal organisms they can get with food and water. Heavy metals are very dangerous for people's health, and we must know their accumulation places, intensity of scatter and integral risk for health. The purpose of this work was to establish links between zones polluted with heavy metals and morbidity caused by pollution with heavy metals. The morbidity caused by heavy metals (Pb, Cu, Zn, Ca and other) in the polluted regions is 1.4-1.5 times higher for adults and teenagers and 1.5-3.9 times higher for children aged under 14 years than the mean morbidity of the same diseases in Lithuania. Hypothetically, it is possible to prognosticate that this problem will grow in future because the ratio of the newly registered and the existing cases of morbidity for children aged under 14 years is 1.3-1.5 times higher than for adults.

  2. Salinity and Conductivity Amendment of Soil Enhanced the Bioelectrochemical Degradation of Petroleum Hydrocarbons

    PubMed Central

    Li, Xiaojing; Wang, Xin; Zhang, Yueyong; Zhao, Qian; Yu, Binbin; Li, Yongtao; Zhou, Qixing

    2016-01-01

    The extreme salinity and high internal resistance of saline-alkali soil contaminated by petroleum hydrocarbons were two key limitations for using the bioelectrochemical remediation. In order to solve two problems, we simply rinsed soil, added carbon fiber to polluted soil. The charge output was enhanced by 110% with increase of the maximum current densities from 81 to 304 mA·m−2 while hydrocarbons degradation rate enhanced by 484%, especially the high molecular weight fractions (C28–C36 of n-alkanes and 4–6 rings of PAHs). These effects were possibly due to the selective enrichment of species belonged to δ-Proteobacteria (Proteobacteria), Flavobacteriia (Bacteroidetes) or Clostridia (Firmicutes), the activities of biological electron transfer and enzymes. As we know, oxygenase gene that directly decided the process of degradation, was surveyed for the first time in soil bioelectrochemical remediation system. The results confirmed that the bio-current stimulated the activities of naphthalene dioxygenase and xylene monooxygenase and thus the hydrocarbons degradation and the electricity generation. Given that electricity generation and the remediation performance are governed by multiple factors, understanding of microbial community and enzyme gene is crucial to promote the power yield and the bioelectrochemical remediation applicability. PMID:27597387

  3. Salinity and Conductivity Amendment of Soil Enhanced the Bioelectrochemical Degradation of Petroleum Hydrocarbons.

    PubMed

    Li, Xiaojing; Wang, Xin; Zhang, Yueyong; Zhao, Qian; Yu, Binbin; Li, Yongtao; Zhou, Qixing

    2016-09-06

    The extreme salinity and high internal resistance of saline-alkali soil contaminated by petroleum hydrocarbons were two key limitations for using the bioelectrochemical remediation. In order to solve two problems, we simply rinsed soil, added carbon fiber to polluted soil. The charge output was enhanced by 110% with increase of the maximum current densities from 81 to 304 mA·m(-2) while hydrocarbons degradation rate enhanced by 484%, especially the high molecular weight fractions (C28-C36 of n-alkanes and 4-6 rings of PAHs). These effects were possibly due to the selective enrichment of species belonged to δ-Proteobacteria (Proteobacteria), Flavobacteriia (Bacteroidetes) or Clostridia (Firmicutes), the activities of biological electron transfer and enzymes. As we know, oxygenase gene that directly decided the process of degradation, was surveyed for the first time in soil bioelectrochemical remediation system. The results confirmed that the bio-current stimulated the activities of naphthalene dioxygenase and xylene monooxygenase and thus the hydrocarbons degradation and the electricity generation. Given that electricity generation and the remediation performance are governed by multiple factors, understanding of microbial community and enzyme gene is crucial to promote the power yield and the bioelectrochemical remediation applicability.

  4. Salinity and Conductivity Amendment of Soil Enhanced the Bioelectrochemical Degradation of Petroleum Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Li, Xiaojing; Wang, Xin; Zhang, Yueyong; Zhao, Qian; Yu, Binbin; Li, Yongtao; Zhou, Qixing

    2016-09-01

    The extreme salinity and high internal resistance of saline-alkali soil contaminated by petroleum hydrocarbons were two key limitations for using the bioelectrochemical remediation. In order to solve two problems, we simply rinsed soil, added carbon fiber to polluted soil. The charge output was enhanced by 110% with increase of the maximum current densities from 81 to 304 mA·m-2 while hydrocarbons degradation rate enhanced by 484%, especially the high molecular weight fractions (C28-C36 of n-alkanes and 4-6 rings of PAHs). These effects were possibly due to the selective enrichment of species belonged to δ-Proteobacteria (Proteobacteria), Flavobacteriia (Bacteroidetes) or Clostridia (Firmicutes), the activities of biological electron transfer and enzymes. As we know, oxygenase gene that directly decided the process of degradation, was surveyed for the first time in soil bioelectrochemical remediation system. The results confirmed that the bio-current stimulated the activities of naphthalene dioxygenase and xylene monooxygenase and thus the hydrocarbons degradation and the electricity generation. Given that electricity generation and the remediation performance are governed by multiple factors, understanding of microbial community and enzyme gene is crucial to promote the power yield and the bioelectrochemical remediation applicability.

  5. Interaction of soil, water and TNT during degradation of TNT on contaminated soil using subcritical water.

    PubMed

    Kalderis, Dimitrios; Hawthorne, Steven B; Clifford, Anthony A; Gidarakos, Evangelos

    2008-11-30

    Subcritical water was used at laboratory scale to reveal information with respect to the degradation mechanism of TNT on contaminated soil. Highly contaminated soil (12% TNT) was heated with water at four different temperatures, 150, 175, 200 and 225 degrees C and samples were obtained at appropriate time intervals. At the same time, similar experiments were performed with TNT spiked on to clean soil, sand and pure water in order to compare and eliminate various factors that may be present in the more complex contaminated soil system. Subcritical water was successful at remediating TNT-contaminated soil. TNT destruction percentages ranged between 98 and 100%. The aim of this work was to study the soil-water-contaminant interaction and determine the main physical parameters that affect TNT degradation. It was shown that the rate-limiting step of the process is the extraction/diffusion of TNT molecules from the soil core to the soil surface, where they degrade. Additionally, it was determined that the soil matrix also catalyses degradation to a lesser extent. Autocatalytic effects were not clearly observed.

  6. Heavy Metal Pollution in Urban Soils of Sopron

    NASA Astrophysics Data System (ADS)

    Horváth, Adrienn; Bidló, András

    2014-05-01

    Keywords: anthropogenic effects, land use types, heavy metal content, polluted urban soils, GIS methods Our aim was to identify the main feedback effects between the town and its environment. In the course of our investigation we have analysed the heavy metal contents of urban soil in Sopron town in Hungary. We collected 208 samples on 104 points from 0 to 10 and from 10 to 20 cm depth in a standard network and also at industrial territories. We have been represented our results in a GIS system. We analysed the soils with Lakanen-Erviö method and we measured 24 elements but we have been focused on Co, Cd, Cu, Pb and Zn. Using the data we observed the relationship between these elements in both layers. In the downtown the acidity of soils were alkaline by the greatest number of point, therefore the pollution of these soils is not leach in deeper layers yet. The lead was very high (> 100 mg Pb/kg) in both layers on the whole area of the town. Urban soils with high copper content (among 611 mg and 1221 mg Cu/kg) have been collected from garden and viticulture areas by us. Cadmium contents were the highest (6.14 mg Cd/kg) in traffic zones, where these values could be more than 3 mg Cd/kg according to the literature. The cobalt and zinc results were under the limits. According to our measurements we founded the highest average values in the soils of parks. This could be contamination of the lead from traffic, which bind in the soil of urban green spaces. Now we could continue our examinations with the investigations of these polluted green areas, which can effect to human health.

  7. Sorption, desorption and degradation of neonicotinoids in four agricultural soils and their effects on soil microorganisms.

    PubMed

    Zhang, Peng; Ren, Chao; Sun, Hongwen; Min, Lujuan

    2017-09-29

    In this study, the sorption, desorption and degradation of three neonicotinoids, imidacloprid (IMI), clothianidin (CLO) and thiacloprid (THI), and their effects on microorganisms in four different agricultural soils were systematically evaluated. The sorption of neonicotinoids on the soils was generally low with distribution coefficients (Kd) up to 16.2L/kg at Ce of 0.05mg/L following the order THI>IMI≈CLO, and the sorption were mainly influenced by the soil organic carbon content. The percentage degradation rates of the pesticides in different soils ranged from 25.4% to 80.9%, all following the order THI>IMI≈CLO. All the three neonicotinoids degraded much faster under non-sterilized conditions than sterilized conditions, indicating considerable contribution of biodegradation. The total degradation or biodegradation of neonicotinoids was the fastest in the soil with the highest organic carbon content, and the neonicotinoids' bioavailability was not the primary influencing factor due to their weak sorption. The chemical degradation was mainly affected by pH and cation exchange capacity. The degradation of neonicotinoids occurred mainly via nitrate reduction, cyano hydrolysis and chloropyridinyl dechlorination. High-throughput sequencing data showed that the microbial community structure and abundance changed greatly in neonicotinoid-spiked soils as compared to the control, which might influence their degradation pathways. Some microbe families associated with the biodegradation of neoniconoids were found, which were all belonging to Proteobacteria and Actinobacteria. The degradation of neoniconoids influenced the soil nitrifying process. The present study provides valuable information for comprehensively understanding the fate of neonicotinoids in soils. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Sphingomonads in Microbe-Assisted Phytoremediation: Tackling Soil Pollution.

    PubMed

    Gatheru Waigi, Michael; Sun, Kai; Gao, Yanzheng

    2017-09-01

    Soil pollution has become a major concern in various terrestrial ecosystems worldwide. One in situ soil bioremediation strategy that has gained popularity recently is microbe-assisted phytoremediation, which is promising for remediating pollutants. Sphingomonads, a versatile bacteria group comprising four well-known genera, are ubiquitous in vegetation grown in contaminated soils. These Gram-negative microbes have been investigated for their ability to induce innate plant growth-promoting (PGP) traits, including the formation of phytohormones, siderophores, and chelators, in addition to their evolutionary adaptations enabling biodegradation and microbe-assisted removal of contaminants. However, their capacity for bacterial-assisted phytoremediation has to date been undervalued. Here, we highlight the specific features, roles, advantages, and challenges associated with using sphingomonads in plant-microbe interactions, from the perspective of future phytotechnologies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Veterinary antibiotic effects on atrazine degradation and soil microorganisms

    USDA-ARS?s Scientific Manuscript database

    Veterinary antibiotics (VAs) in manure applied to agricultural lands may change agrichemical degradation by altering soil microbial community structure or function. The objectives of this study were to investigate the influence of two VAs, sulfamethazine (SMZ) and oxytetracycline (OTC), on atrazine ...

  10. Soil degradation in India: Challenges and potential solutions

    USDA-ARS?s Scientific Manuscript database

    Soil degradation in India is estimated to occur on 147 Mha of land, including 94 Mha from water erosion, 16 Mha from acidification, 14 Mha from flooding, 9 Mha from wind erosion, 6 Mha from salinity, and 7 Mha from a combination of factors. India supports 18% of the world’s human population and 15%...

  11. Sorption and degradation of estrogen conjugates in agricultural soils

    USDA-ARS?s Scientific Manuscript database

    The natural estrogenic hormone, 17'-estradiol (E2), can disrupt the endocrine system of some aquatic species at ng/L concentrations. Laboratory studies have shown low potentials for E2 persistence and mobility in the environment due to high degradation and soil retention. However, field studies have...

  12. Toxicity testing of heavy-metal-polluted soils with algae Selenastrum capricornutum: a soil suspension assay.

    PubMed

    Aruoja, Villem; Kurvet, Imbi; Dubourguier, Henri-Charles; Kahru, Anne

    2004-08-01

    A small-scale Selenastrum capricornutum (Rhapidocelis subcapitata) growth inhibition assay was applied to the toxicity testing of suspensions of heavy-metal-polluted soils. The OECD 201 standard test procedure was followed, and algal biomass was measured by the fluorescence of extracted chlorophyll. The soils, which contained up to (per kilogram) 1390 mg of Zn, 20 mg of Cd, and 1050 mg of Pb were sampled around lead and zinc smelters in northern France. The water extractability of the metals in suspensions (1 part soil/99 parts water w/v) was not proportional to the pollution level, as extractability was lower for soil samples that were more polluted. Thus, the same amount of metals could be leached out of soils of different levels of pollution, showing that total concentrations of heavy metals in soil (currently used for risk assessment purposes) are poor predictors of the real environmental risk via the soil-water path. Despite high concentrations of water-extracted zinc (0.6-1.4 mg/L of Zn in the test), exceeding by approximately 10-fold the EC(50) value for S. capricornutum (0.1 mg Zn/L), 72-h algal growth in the soil extracts was comparable or better than growth in the standard control OECD mineral medium. The soil suspension stimulated the growth of algae up to eightfold greater than growth using the OECD control medium. Growth stimulation of algae was observed even when soil suspensions contained up to 12.5 mg Zn/L and could not be explained by supplementary nitrogen, phosphorous, and carbonate leached from the soil. However, if the growth of algae in suspensions of clean and polluted soils was compared, a dose-dependent inhibitory effect of metals on algal growth was demonstrated. Thus, as soil contains nutrients/supplements that mask the adverse effect of heavy metals, a clean soil that has properties similar to the polluted soils should be used instead of mineral salt solution as a control for analysis of the ecotoxicity of soils. Copyright 2004 Wiley

  13. Degradation of PAHs in soil by Lasiodiplodia theobromae and enhanced benzo[a]pyrene degradation by the addition of Tween-80.

    PubMed

    Wang, Cuiping; Liu, Haibin; Li, Jing; Sun, Hongwen

    2014-09-01

    Benzo[a]pyrene (BaP), a five-ring polycyclic aromatic hydrocarbon (PAH), which has carcinogenic potency, is highly recalcitrant and resistant to microbial degradation. A novel fungus, Lasiodiplodia theobromae (L. theobromae), which can degrade BaP as a sole carbon source in liquid, was isolated in our laboratory. To prompt the further application of L. theobromae in remediation of sites polluted by BaP and other PAHs, the present study was targeted toward the removal of BaP and PAHs from soil by L. theobromae. The degradation of BaP by L. theobromae was studied using a soil spiked with 50 mg/kg BaP. L. theobromae could remove 32.1 % of the BaP after 35 days of cultivation. Phenanthrene (PHE) inhibited BaP degradation as a competitive substrate. The tested surfactants enhanced BaP degradation in soil by different extents, and a removal rate of 92.1 % was achieved at a Tween-80 (TW-80) concentration of 5 g/kg. It was revealed that TW-80 could not only enhance BaP bioavailability by increasing its aqueous solubility and decreasing the size of its colloid particles but also increase enzyme secretion from L. theobromae and the population of L. theobromae. Moreover, ergosterol content together with the biomass C indicated the increase in L. theobromae biomass during the BaP biodegradation process in soils. Finally, a soil from a historically PAH-contaminated field at Beijing Coking Plant in China was tested to assess the feasibility of applying L. theobromae in the remediation of polluted sites. The total removal rate of PAHs by L. theobromae was 53.3 %, which is 13.1 % higher than that by Phanerochaete chrysosporium (P. chrysosporium), an effective PAH degrader. The addition of TW-80 to the field soil further enhanced PAH degradation to 73.2 %. Hence, L. theobromae is a promising novel strain to be implemented in the remediation of soil polluted by PAHs.

  14. Field evaluation of the lignin-degrading fungus 'phanerochaete sordida' to treat creosote-contaminated soil

    SciTech Connect

    Davis, M.W.; Glaser, J.A.; Evans, J.W.; Lamar, R.T.

    1993-01-01

    A field study to determine the ability of selected lignin-degrading fungi to remediate soil contaminated with pentachlorophenol and creosote was performed at a wood treating facility in south central Mississippi in the Autumn of 1991. The study was designed to evaluate 7 fungal treatments and appropriate control treatments. Soil concentrations of 14 priority pollutant polycyclic aromatic hydrocarbon (PAH) components of creosote were measured over time to determine treatment efficacies. Fungal treatments involved mixing fungal inocula and aspen chips into the contaminated soil and maintaining moisture by irrigation and aeration by tillage. PAHs of more than 4 rings persisted at their original concentrations during the 8 wk course of the study for all treatments and controls.

  15. Treating soil-washing fluids polluted with oxyfluorfen by sono-electrolysis with diamond anodes.

    PubMed

    Vieira Dos Santos, E; Sáez, C; Cañizares, P; Martínez-Huitle, C A; Rodrigo, M A

    2017-01-01

    This works is focused on the treatment by sono-electrolysis of the liquid effluents produced during the Surfactant-Aided Soil-Washing (SASW) of soils spiked with herbicide oxyfluorfen. Results show that this combined technology is very efficient and attains the complete mineralization of the waste, regardless of the surfactant/soil radio applied in the SASW process (which is the main parameter of the soil remediation process and leads to very different wastes). Both the surfactant and the herbicide are completely degraded, even when single electrolysis is used; and only two intermediates are detected by HPLC in very low concentrations. Conversely, the efficiency of single sonolysis approach, for the oxidation of pollutant, is very low and just small changes in the herbicides and surfactant concentrations are observed during the tests carried out. Sono-electrolysis with diamond electrodes achieved higher degradation rates than those obtained by single sonolysis and/or single electrolysis with diamond anodes. A key role of sulfate is developed, when it is released after the electrochemical degradation of surfactant. The efficient catalytic effect observed which can be explained by the anodic formation of persulfate and the later, a sono-activation is attained to produce highly efficient sulfate radicals. The effect of irradiating US is more importantly observed in the pesticide than in the surfactant, in agreement with the well-known behavior of these radicals which are known to oxidize more efficiently aromatic compounds than aliphatic species. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Remediation of soils polluted with lindane using surfactant-aided soil washing and electrochemical oxidation.

    PubMed

    Muñoz-Morales, M; Braojos, M; Sáez, C; Cañizares, P; Rodrigo, M A

    2017-10-05

    In this work the complete treatment of soil spiked with lindane is studied using surfactant-aided soil-washing (SASW) to exhaust lindane from soil and electrolysis with diamond anodes to mineralize lindane from the soil washing fluid (SWF) waste. Results demonstrated that this technological approach is efficient and allow to remove this hazardous pollutant from soil. They also pointed out the significance of the ratio surfactant/soil in the efficiency of the SASW process and in the performance of the later electrolysis used to mineralize the pollutant. Larger values of this parameter lead to effluents that undergo a very efficient treatment which allows the depletion of lindane for applied charges lower than 15AhL(-1) and the recovery of more than 70% of the surfactant for the regeneration of the SWF. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Representing soil pollution by heavy metals using continuous limitation scores

    NASA Astrophysics Data System (ADS)

    Romić, Marija; Hengl, Tomislav; Romić, Davor; Husnjak, Stjepan

    2007-10-01

    The paper suggests a methodology to represent overall soil pollution in a sampled area using continuous limitation scores. The interpolated heavy metal concentrations are first transformed to limitation scores using the exponential transfer function determined by using two threshold values: permissible concentration (0 limitation points) and seriously polluted soil (4 limitation points). The limitation scores can then be summed to produce the map of cumulative limitation scores and visualize the most critically polluted areas. The methodology was illustrated using the 784 soil samples analyzed for Cd, Cr, Cu, Ni, Pb and Zn in the central region of Croatia. The samples were taken at 1×1 and 2×2 km grids and at fixed depths of 20 cm. Heavy metal concentrations in soil were determined by ICP-OES after microwave assisted aqua regia digestion. The sampled concentrations were interpolated using block regression-kriging with geology and land cover maps, terrain parameters and industrialization parameters as auxiliary predictors. The results showed that the best auxiliary predictors are geological map, ground water depth, NDVI and slope map and distance to urban areas. The spatial prediction was satisfactory for Cd, Ni, Pb and Zn, and somewhat less satisfactory for Cu and Cr. The final map of cumulative limitation scores showed that 33.5% of the total area is suitable for organic agriculture and 7.2% of the total area is seriously polluted by one or more heavy metals. This procedure can be used to assess suitability of soils for agricultural production and as a basis for possible legal commitments to maintain the soil quality.

  18. [Comparison of efficiencies of oil-oxidizing Dietzia maris strain and stimulation of natural microbial communities in remediation of polluted soil].

    PubMed

    Pleshakova, E V; Dubrovskaia, E V; Turkovskaia, O V

    2008-01-01

    Two approaches to bioremediation of oil-polluted soils are compared: use of active degrader strain Dietzia maris AM3 and stimulation of natural microflora. Introduction of D. maris AM3 to soil freshly polluted with oil accelerated its remediation twofold within the first month in comparison with the stimulation. After three months, the purification degrees were approximately equal. By the end of bioremediation, the soil with the introduced strain had higher dehydrogenase and catalase activities. In soil with multiyear pollution, introduced strain D. maris AM3 did not affect the rate of oil product degradation, and no significant differences between the two bioremediation methods were detected in purification degree and biological activity of soil after three months.

  19. Molecular profiling of permafrost soil organic carbon composition and degradation

    NASA Astrophysics Data System (ADS)

    Gu, B.; Mann, B.

    2014-12-01

    Microbial degradation of soil organic matter (SOM) is a key process for terrestrial carbon (C) cycling, though the dynamics of these transformations remain unclear at the molecular level. This study reports the application of ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) to profile molecular components of Arctic SOM collected from the surface water and the mineral horizon of a low-centered polygon soil at Barrow Environmental Observatory (BEO), Barrow, Alaska. Soil samples were subjected to anaerobic warming experiments for a period of 40 days, and the SOM was extracted before and after the incubation to determine the components of organic C that were degraded over the course of the study. A CHO index based on molecular composition data was utilized to codify SOM components according to their observed degradation potential. Carbohydrate- and lignin-like compounds in the water-soluble fraction (WSF) demonstrated a high degradation potential, while structures with similar stoichiometries in the base-soluble fraction (BSF) were not readily degraded. The WSF of SOM also shifted to a wider range of measured molecular masses including an increased prevalence of larger compounds, while the size distribution of compounds in the BSF changed little over the same period. Additionally, the molecular profiling data indicated an apparently ordered incorporation of organic nitrogen in the BSF immobilized as primary and secondary amines, possibly as components of N-heterocycles, which may provide insight into nitrogen immobilization or mobilization processes in SOM. Our study represents an important step forward for studying Arctic SOM with improved understanding of the molecular properties of soil organic C and the ability to represent SOM in climate models that will predict the impact of climate change on soil C and nutrient cycling.

  20. Physical insights into the sonochemical degradation of recalcitrant organic pollutants with cavitation bubble dynamics.

    PubMed

    Sivasankar, Thirugnanasambandam; Moholkar, Vijayanand S

    2009-08-01

    This paper tries to discern the mechanistic features of sonochemical degradation of recalcitrant organic pollutants using five model compounds, viz. phenol (Ph), chlorobenzene (CB), nitrobenzene (NB), p-nitrophenol (PNP) and 2,4-dichlorophenol (2,4-DCP). The sonochemical degradation of the pollutant can occur in three distinct pathways: hydroxylation by ()OH radicals produced from cavitation bubbles (either in the bubble-bulk interfacial region or in the bulk liquid medium), thermal decomposition in cavitation bubble and thermal decomposition at the bubble-liquid interfacial region. With the methodology of coupling experiments under different conditions (which alter the nature of the cavitation phenomena in the bulk liquid medium) with the simulations of radial motion of cavitation bubbles, we have tried to discern the relative contribution of each of the above pathway to overall degradation of the pollutant. Moreover, we have also tried to correlate the predominant degradation mechanism to the physico-chemical properties of the pollutant. The contribution of secondary factors such as probability of radical-pollutant interaction and extent of radical scavenging (or conservation) in the medium has also been identified. Simultaneous analysis of the trends in degradation with different experimental techniques and simulation results reveals interesting mechanistic features of sonochemical degradation of the model pollutants. The physical properties that determine the predominant degradation pathway are vapor pressure, solubility and hydrophobicity. Degradation of Ph occurs mainly by hydroxylation in bulk medium; degradation of CB occurs via thermal decomposition inside the bubble, degradation of PNP occurs via pyrolytic decomposition at bubble interface, while hydroxylation at bubble interface contributes to degradation of NB and 2,4-DCP.

  1. Combating land degradation: the potential of soil reconversion

    NASA Astrophysics Data System (ADS)

    Tobias, Silvia; Conen, Franz; Duss, Adrian; Wenzel, Leonore; Buser, Christine; Alewell, Christine

    2017-04-01

    Land degradation is usually not seen as a major problem in industrialised countries, although continuous soil sealing for human settlements and infrastructure entails the loss of agricultural land, landscape fragmentation and the loss of natural habitats. In many European countries, land-take on greenfields is unbowed, while, at the same time, there is a considerable number of unused brownfields, like abandoned rail yards and industrial or military sites. In addition, many new by-pass roads have been constructed to take up the volume of traffic and unburden the towns and villages from traffic emissions, but the old roads are rarely downgraded or reconverted and risk being used as shortcuts. Today the sealed area exceeds the requirements of the current generation and contributes to degraded land with heavily disturbed soil-borne ecosystem services. Soil reconversion, i.e. replacing a sealed surface with soil to restore ecosystem services, could mitigate this unsustainable trend that restricts the options of future generations. This contribution discusses the potential and challenges of soil reconversion to reduce net soil loss. The expanses of brownfield area vary between countries, whereas the rate of new soil sealing is still high in most countries and soil reconversion should be considered more. Our research revealed that the current techniques enable successful restoration of agricultural soils and pioneer habitats on site. However, reconverting single small areas can hardly mitigate landscape fragmentation at a regional scale. The same principle prevails as for soil sealing, but in the inverse way: the benefit of soil reconversion may appear small for single cases, but in the sum soil reconversion might be effective. Today, many brownfield areas stay sealed because of economic and political reasons, or because the potential benefit from restoring ecosystem services at these brownfield sites is not known. We developed a mapping approach to assess the potential

  2. Organic Matter as an Indicator of Soil Degradation

    NASA Astrophysics Data System (ADS)

    Romero Diaz, Asuncion; Damian Ruiz Sinoga, Jose

    2010-05-01

    Numerous and expensive physical-chemical tests are often carried out to determine the level of soil degration. This study was to find one property, as Organic Matter, which is usually analyzed for determine the soil degradation status. To do this 19 areas in the south and southeast of the Iberian Peninsula (provinces of Málaga, Granada, Almería y Murcia) were selected and a wide sampling process was carried out. Sampling points were spread over a wide pluviometric gradient (from 1100 mm/yr to 232 mm/yr) covering the range from Mediterranean wet to dry. 554 soil surface samples were taken from soil (0-10 cm) and the following properties were analyzed: Texture, Organic Matter (OM), Electric Conductivity (EC), Aggregate Stability (AE) y Cation Exchange Capacity (CEC). These properties were intercorrelated and also with rainfall and the K factor of soil erosion, calculated for each sampling point. Los results obtained by applying the Pearson correlation coefficient to the database shows how as rainfall increases so does OM content (0,97) and la CEC (0,89), but K factor (-0,80) reacts inversely. The content of OM in the soil is related to its biological activity and this in turn is the result of available wáter within the system and, consequently, rainfall. This is specially important in fragile and complex ecogeomorphological systems as is the case of the Mediterranean, where greater or lesser rainfall is similarly reflected in the levels of increase or decrease of soil organic matter. This affirmation is reinforced by linking the organic matter of the soil with other indicative properties such as CEC and erosion, as has been shown by various authors (Imeson y Vis, 1984; De Ploey & Poesen, 1985; Le Bissonnais, 1996; Boix-Fayos et al., 2001; Cammeraat y Imeson, 1998; Cerdá, 1998). As has been stated, there is a direct relationship between rainfall, organic matter content, cation exchange capacity, structural stability, and the resistence to soil erosion factor

  3. Adsorption and degradation of triclosan and triclocarban in soils and biosolids-amended soils.

    PubMed

    Wu, Chenxi; Spongberg, Alison L; Witter, Jason D

    2009-06-10

    Triclosan and triclocarban are antibacterial agents that are widely used in numerous personal care products. Limited information is available on their environmental behavior in soils and soils land applied with wastewaters and biosolids. In this study, laboratory experiments were performed to investigate their adsorption and degradation in soils. Both antibacterial agents adsorbed strongly to the sandy loam and silty clay soils with and without addition of biosolids, with distribution coefficients (K(d)) ranging from 178 to 264 L kg(-1) for triclosan and from 763 to 1187 L kg(-1) for triclocarban. Sorption of triclosan decreased with increase in soil pH from 4 to 8, whereas triclocarban sorption showed no effect within the tested pH range. Competitive sorption was observed when triclosan and triclocarban coexisted, but the cosolute effect was concentration dependent. Biosolids amendment increased the sorption of triclosan and triclocarban, likely due to the addition of soil organic matter, but displayed no significant effect on degradation.

  4. Enzymatic technologies for remediation of hydrophobic organic pollutants in soil.

    PubMed

    Eibes, G; Arca-Ramos, A; Feijoo, G; Lema, J M; Moreira, M T

    2015-11-01

    Worldwide there are numerous contaminated sites as a result of the widespread production and use of chemicals in industrial and military activities as well as poor schemes of waste disposal and accidental spillages. The implementation of strategies for decontamination and restoration of polluted sites has become a priority, being bioremediation with biological agents a promising alternative. Enzyme-based technologies offer several advantages over the use of microbial cells, provided that the biocatalyst meets specific requirements: efficiency to remove the target pollutant/s, non-dependency on expensive coenzymes or cofactors, enzyme stability, and an affordable production system. In this mini-review, the direct application of enzymes for in situ soil bioremediation is explored, and also novel ex situ enzymatic technologies are presented. This new perspective provides a valuable insight into the different enzymatic alternatives for decontamination of soils. Examples of recent applications are reported, including pilot-scale treatments and patented technologies, and the principles of operation and the main requirements associated are described. Furthermore, the main challenges regarding the applicability of enzymatic technologies for remediation of hydrophobic organic pollutants from soil are discussed.

  5. Ecological risk assessment of soil pollution with heavy metals

    SciTech Connect

    Kuperman, R.G.

    1995-12-31

    The structure and function of soil ecosystems in an area with a wide range of concentrations of heavy metals were studied in portions of the US Army`s Aberdeen Proving Ground, Maryland. The objective of this project was to develop and test the efficacy of a comprehensive methodology for assessing ecological impacts of soil contamination. A hierarchical approach which integrated biotic parameters and ecosystem processes was used to give insight into the mechanisms that lead to alterations in the structure and function of soil ecosystems in contaminated areas. This approach involved (1) a thorough survey of the soil biota to establish community structure, (2) laboratory and field tests on critical ecosystem processes, (3) toxicity trials, and (4) the use of spatial analyses to provide input in the decision making process. Soil invertebrate communities showed significant reductions in the abundance of several taxonomic and trophic groups in contaminated areas. The numbers of soil microorganisms were lower in areas of soil contamination. Ten-to-fifty fold reductions in enzyme activities were observed as heavy metal concentrations increased. These results suggest that soil contamination with heavy metals may have detrimental effects on soil biota and the rates of organic matter degradation and subsequent release of nutrients to aboveground communities in the area. The proposed methodology appears to offer an efficient and potentially cost saving tool for remedial investigations at contaminated sites.

  6. Bioelectrochemical stimulation of petroleum hydrocarbon degradation in saline soil using U-tube microbial fuel cells.

    PubMed

    Wang, Xin; Cai, Zhang; Zhou, Qixing; Zhang, Zhineng; Chen, Cuihong

    2012-02-01

    Bioremediation is a cost-effective and eco-friendly approach to decontaminate soils polluted by petroleum hydrocarbons. However, this technique usually requires a long time due to the slow degradation rate by bacteria. By applying U-tube microbial fuel cells (MFCs) designed here, the degradation rate of petroleum hydrocarbons close to the anode (<1 cm) was enhanced by 120% from 6.9 ± 2.5% to 15.2 ± 0.6% with simultaneous 125 ± 7 C of charge output (0.85 ± 0.05 mW/m(2) , 1 kΩ) in the tested period (25 days). Hydrocarbon fingerprint analysis showed that the degradation rate of both alkanes and polycyclic aromatic hydrocarbons (PAHs) was accelerated. The decrease of initial water content from 33% to 28% and 23% resulted in a decrease on charge output and hydrocarbon degradation rate, which could be attributed to the increase of internal resistance. A salt accumulation was observed in each reactor due to the evaporation of water from the air-cathode, possibly inhibited the activity of exoelectrogenic bacteria (EB) and resulted in the elimination of the current at the end of the tested period. The number of hydrocarbon degradation bacteria (HDB) in soil close to the anode increased by nearly two orders of magnitude in the MFC assisted system (373 ± 56 × 10(3)  CFU/g-soil) than that in the disconnected control (8 ± 2 × 10(3)  CFU/g-soil), providing a solid evidence for in situ biostimulation of HDB growth by colonization of EB in the same system.

  7. Effect of the polarity reversal frequency in the electrokinetic-biological remediation of oxyfluorfen polluted soil.

    PubMed

    Barba, Silvia; Villaseñor, José; Rodrigo, Manuel A; Cañizares, Pablo

    2017-03-03

    This work studies the feasibility of the periodic polarity reversal strategy (PRS) in a combined electrokinetic-biological process for the remediation of clayey soil polluted with a herbicide. Five two-weeks duration electrobioremediation batch experiments were performed in a bench scale set-up using spiked clay soil polluted with oxyfluorfen (20 mg kg(-1)) under potentiostatic conditions applying an electric field between the electrodes of 1.0 V cm(-1) (20.0 V) and using PRS with five frequencies (f) ranging from 0 to 6 d(-1). Additionally, two complementary reference tests were done: single bioremediation and single electrokinetic. The microbial consortium used was obtained from an oil refinery wastewater treatment plant and acclimated to oxyfluorfen degradation. Main soil conditions (temperature, pH, moisture and conductivity) were correctly controlled using PRS. On the contrary, the electroosmotic flow clearly decreased as f increased. The uniform soil microbial distribution at the end of the experiments indicated that the microbial activity remained in every parts of the soil after two weeks when applying PRS. Despite the adapted microbial culture was capable of degrade 100% of oxyfluorfen in water, the remediation efficiency in soil in a reference test, without the application of electric current, was negligible. However, under the low voltage gradients and polarity reversal, removal efficiencies between 5% and 15% were obtained, and it suggested that oxyfluorfen had difficulties to interact with the microbial culture or nutrients and that PRS promoted transport of species, which caused a positive influence on remediation. An optimal f value was observed between 2 and 3 d(-1).

  8. Degradation of metaflumizone in soil: impact of varying moisture, light, temperature, atmospheric CO2 level, soil type and soil sterilization.

    PubMed

    Chatterjee, Niladri Sekhar; Gupta, Suman; Varghese, Eldho

    2013-01-01

    Soil is a major sink for the bulk of globally used pesticides. Hence, fate of pesticides in soil under the influence of various biotic and abiotic factors becomes important for evaluation of stability and safety. This paper presents the impact of varying moisture, light, temperature, atmospheric CO(2) level, soil type and soil sterilization on degradation of metaflumizone, a newly registered insecticide in India. Degradation of metaflumizone in soil followed the first order reaction kinetics and its half life values varied from ~20 to 150 d. Under anaerobic condition, degradation of metaflumizone was faster (t(½) 33.4 d) compared to aerobic condition (t(½) 50.1 d) and dry soil (t(½) 150.4 d). Under different light exposures, degradation was the fastest under UV light (t(½) 27.3 d) followed by Xenon light (t(½) 43 d) and dark condition (t(½) 50.1 d). Degradation rate of metaflumizone increased with temperature and its half life values ranged from 30.1 to 100.3d. Elevated atmospheric CO(2) level increased the degradation in soil (t(½) 20.1-50.1 d). However, overall degradation rate was the fastest at 550 ppm atmospheric CO(2) level, followed by 750 ppm and ambient level (375 ppm). Degradation of metaflumizone was faster in Oxisol (pH 5.2, Total Organic Carbon 1.2%) compared to Inceptisol (pH 8.15, TOC 0.36%). In sterile soil, only 5% dissipation of initial concentration was observed after 90 d of sampling. Under various conditions, 4-cyanobenzoic acid (0.22-1.86 mg kg(-1)) and 4-trifluoromethoxy aniline (0.21-1.23 mg kg(-1)) were detected as major degradation products.

  9. Gradient analysis reveals a copper paradox on floodplain soils under long-term pollution by mining waste.

    PubMed

    Nikolic, Nina; Nikolic, Miroslav

    2012-05-15

    Arable alluvial soils are a globally important resource under increasing pressure from both industrial pollution and intensified agricultural land use. Quality of agricultural soils is ultimately defined by crop yields; it is however seldom feasible to study the consequences of complex soil pollution on crops under field conditions. This work analyses the long term effects of two gradients: spatial (relative distance from the water channel) and land use intensity (cropping frequency) on soil properties and model crop (barley) response. On an exceptional model locality in Eastern Serbia, degraded by fluvial deposition of sulphidic copper tailings during 50 years, multivariate analysis shows that land use accelerates the substitution of high plant available Cu by nutrient deficiency (primarily P and microelements) and excessive exchangeable Al. Though agronomic soil quality might not differ along the land use gradient, the environmental consequences do drastically change. The observed apparent "paradoxes" (e.g. soil Cu decreases towards the pollution source; higher yields might coincide with higher soil and leaf Cu concentrations; and leaching of Cu does not restore soils agronomic quality) can be explained by a) the Cu retention patterns along the transects, b) importance of higher SOM and nutrient availability for modifications of Cu toxicity, and c) the existence of plant adaptation mechanisms which can considerably counteract the adverse soil conditions. Land use-induced nutrient deficiency can counteract the positive effects of decreased Cu levels. In a long run, accelerated Cu mobilisation is likely to increase vulnerability of these soils to further environmental hazards. This study demonstrates the clear and consistent patterns in soil properties and plant response along the gradients and points out the probable long-term environmental trends in a "would be" scenario for agricultural use of similar polluted soils. Copyright © 2012 Elsevier B.V. All rights

  10. Degradation of soils as a result of human-induced transformation of their water regime and soil-protective practice

    NASA Astrophysics Data System (ADS)

    Zaidel'Man, F. R.

    2009-01-01

    The adverse human-induced changes in the water regime of soils leading to their degradation are considered. Factors of the human activity related to the water industry, agriculture, and silviculture are shown to play the most active role in the soil degradation. Among them are the large-scale hydraulic works on rivers, drainage and irrigation of soils, ameliorative and agricultural impacts, road construction, and uncontrolled impacts of industry and silviculture on the environment. The reasons for each case of soil degradation related to changes in the soil water regime are considered, and preventive measures are proposed. The role of secondary soil degradation processes is shown.

  11. Microbial taxa and functional genes shift in degraded soil with bacterial wilt

    PubMed Central

    Zhang, Hongchun; Wang, Rui; Chen, Shu; Qi, Gaofu; He, Zhili; Zhao, Xiuyun

    2017-01-01

    Soil degradation is a serious global problem, but little is known about how soil microbial communities respond to soil degradation as well as their feedback to ecosystem functioning. In this study, we found the microbial community composition, structure and functional potential significantly altered in the degraded soils with bacterial wilt (termed as degraded soils). Compared with healthy soils, OTU richness of beneficial microorganisms were significantly decreased, but OTU richness of pathogenic microorganisms were significantly increased in the degraded soils. Functional gene array (GeoChip 5.0) analysis showed the functional metabolic potential of genes involved in stress, virulence, sulfur cycle, metal resistance, degradation of plant cell wall was significantly increased in the degraded soils. Increased functional metabolic potential of these genes may be related to the acidification and severe plant disease of degraded soils. Biological activity of degraded soils was obviously decreased with weakened soil enzyme activities when compared to the healthy soils. Soil pH and enzyme activities were negatively correlated with the abundance of genes involved in sulfur cycle, virulence, and stress responses. This study provides new insights into our understanding of soil microbial community responses to soil degradation. PMID:28051173

  12. Degradation behavior of sulfadiazine in soils under different conditions.

    PubMed

    Yang, Ji-Feng; Ying, Guang-Guo; Yang, Li-Hua; Zhao, Jian-Liang; Liu, Feng; Tao, Ran; Yu, Zhi-Qiang; Peng, Ping'an

    2009-03-01

    This study investigated the degradation of sulfadiazine in three soils and also determined its sorption and hydrolysis behaviors as well. At the spike concentration of 10 mg/kg, the half-lives for sulfadiazine in the aerobic nonsterile soils ranged from 12 days to 18 days. Sulfadiazine was more persistent in the anoxic soils with the half-lives ranging between 57 days and 237 days and soil microorganisms played little role in the dissipation process under anoxic conditions. The decline in sulfadiazine concentrations was also observed in the sterile soils under aerobic conditions. Hydrolysis could not explain this phenomena as hydrolysis of sulfadiazine was pH dependent. Sulfadiazine only hydrolyzed to a very limited degree at acidic pH. Increased sorption was observed for sulfadiazine in soil 1 (pH 4.3) when the contact time increased to 14 days, but no significant increase in sorption was found for soil 2 (pH 7.2) and soil 3 (pH 8.5).

  13. Degradation of soil fertility can cancel pollination benefits in sunflower.

    PubMed

    Tamburini, Giovanni; Berti, Antonio; Morari, Francesco; Marini, Lorenzo

    2016-02-01

    Pollination and soil fertility are important ecosystem services to agriculture but their relative roles and potential interactions are poorly understood. We explored the combined effects of pollination and soil fertility in sunflower using soils from a trial characterized by different long-term input management in order to recreate plausible levels of soil fertility. Pollinator exclusion was used as a proxy for a highly eroded pollination service. Pollination benefits to yield depended on soil fertility, i.e., insect pollination enhanced seed set and yield only under higher soil fertility indicating that limited nutrient availability may constrain pollination benefits. Our study provides evidence for interactions between above- and belowground ecosystem services, highlighting the crucial role of soil fertility in supporting agricultural production not only directly, but also indirectly through pollination. Management strategies aimed at enhancing pollination services might fail in increasing yield in landscapes characterized by high soil service degradation. Comprehensive knowledge about service interactions is therefore essential for the correct management of ecosystem services in agricultural landscapes.

  14. A review of the impacts of degradation threats on soil properties in the UK.

    PubMed

    Gregory, A S; Ritz, K; McGrath, S P; Quinton, J N; Goulding, K W T; Jones, R J A; Harris, J A; Bol, R; Wallace, P; Pilgrim, E S; Whitmore, A P

    2015-10-01

    National governments are becoming increasingly aware of the importance of their soil resources and are shaping strategies accordingly. Implicit in any such strategy is that degradation threats and their potential effect on important soil properties and functions are defined and understood. In this paper, we aimed to review the principal degradation threats on important soil properties in the UK, seeking quantitative data where possible. Soil erosion results in the removal of important topsoil and, with it, nutrients, C and porosity. A decline in soil organic matter principally affects soil biological and microbiological properties, but also impacts on soil physical properties because of the link with soil structure. Soil contamination affects soil chemical properties, affecting nutrient availability and degrading microbial properties, whilst soil compaction degrades the soil pore network. Soil sealing removes the link between the soil and most of the 'spheres', significantly affecting hydrological and microbial functions, and soils on re-developed brownfield sites are typically degraded in most soil properties. Having synthesized the literature on the impact on soil properties, we discuss potential subsequent impacts on the important soil functions, including food and fibre production, storage of water and C, support for biodiversity, and protection of cultural and archaeological heritage. Looking forward, we suggest a twin approach of field-based monitoring supported by controlled laboratory experimentation to improve our mechanistic understanding of soils. This would enable us to better predict future impacts of degradation processes, including climate change, on soil properties and functions so that we may manage soil resources sustainably.

  15. Long-term pollution by chlordecone of tropical volcanic soils in the French West Indies: a simple leaching model accounts for current residue.

    PubMed

    Cabidoche, Y-M; Achard, R; Cattan, P; Clermont-Dauphin, C; Massat, F; Sansoulet, J

    2009-05-01

    Chlordecone was applied between 1972 and 1993 in banana fields of the French West Indies. This resulted in long-term pollution of soils and contamination of waters, aquatic biota, and crops. To assess pollution level and duration according to soil type, WISORCH, a leaching model based on first-order desorption kinetics, was developed and run. Its input parameters are soil organic carbon content (SOC) and SOC/water partitioning coefficient (K(oc)). It accounts for current chlordecone soil contents and drainage water concentrations. The model was valid for andosol, which indicates that neither physico-chemical nor microbial degradation occurred. Dilution by previous deep tillages makes soil scrapping unrealistic. Lixiviation appeared the main way to reduce pollution. Besides the SOC and rainfall increases, K(oc) increased from nitisol to ferralsol and then andosol while lixiviation efficiency decreased. Consequently, pollution is bound to last for several decades for nitisol, centuries for ferralsol, and half a millennium for andosol.

  16. Response of bacterial pdo1, nah, and C12O genes to aged soil PAH pollution in a coke factory area.

    PubMed

    Han, Xue-Mei; Liu, Yu-Rong; Zheng, Yuan-Ming; Zhang, Xiao-Xia; He, Ji-Zheng

    2014-01-01

    Soil pollution caused by polycyclic aromatic hydrocarbons (PAHs) is threatening human health and environmental safety. Investigating the relative prevalence of different PAH-degrading genes in PAH-polluted soils and searching for potential bioindicators reflecting the impact of PAH pollution on microbial communities are useful for microbial monitoring, risk evaluation, and potential bioremediation of soils polluted by PAHs. In this study, three functional genes, pdo1, nah, and C12O, which might be involved in the degradation of PAHs from a coke factory, were investigated by real-time quantitative PCR (qPCR) and clone library approaches. The results showed that the pdo1 and C12O genes were more abundant than the nah gene in the soils. There was a significantly positive relationship between the nah or pdo1 gene abundances and PAH content, while there was no correlation between C12O gene abundance and PAH content. Analyses of clone libraries showed that all the pdo1 sequences were grouped into Mycobacterium, while all the nah sequences were classified into three groups: Pseudomonas, Comamonas, and Polaromonas. These results indicated that the abundances of nah and pdo1 genes were positively influenced by levels of PAHs in soil and could be potential microbial indicators reflecting the impact of soil PAH pollution and that Mycobacteria were one of the most prevalent PAHs degraders in these PAH-polluted soils. Principal component analysis (PCA) and correlation analyses between microbial parameters and environmental factors revealed that total carbon (TC), total nitrogen (TN), and dissolved organic carbon (DOC) had positive effects on the abundances of all PAH-degrading genes. It suggests that increasing TC, TN, and DOC inputs could be a useful way to remediate PAH-polluted soils.

  17. Bioremediation of diuron contaminated soils by a novel degrading microbial consortium.

    PubMed

    Villaverde, J; Rubio-Bellido, M; Merchán, F; Morillo, E

    2017-03-01

    Diuron is a biologically active pollutant present in soil, water and sediments. It is persistent in soil, water and groundwater and slightly toxic to mammals and birds as well as moderately toxic to aquatic invertebrates. Its principal product of biodegradation, 3,4-dichloroaniline, exhibits a higher toxicity than diuron and is also persistent in the environment. On this basis, the objective of the study was to determine the potential capacity of a proposed novel diuron-degrading microbial consortium (DMC) for achieving not only diuron degradation, but its mineralisation both in solution as well as in soils with different properties. The consortium was tested in a soil solution where diuron was the only carbon source, and more than 98.8% of the diuron initially added was mineralised after only a few days. The consortium was composed of three diuron-degrading strains, Arthrobacter sulfonivorans, Variovorax soli and Advenella sp. JRO, the latter had been isolated in our laboratory from a highly contaminated industrial site. This work shows for the first time the potential capacity of a member of the genus Advenella to remediate pesticide-contaminated soils. However, neither of the three strains separately achieved mineralisation (ring-(14)C) of diuron in a mineral medium (MSM) with a trace nutrient solution (NS); combined in pairs, they mineralised 40% of diuron in solution, but the most relevant result was obtained in the presence of the three-member consortium, where complete diuron mineralisation was achieved after only a few days. In the presence of the investigated soils in suspension, the capacity of the consortium to mineralise diuron was evaluated, achieving mineralisation of a wide range of herbicides from 22.9 to 69.0%. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Using biochar for remediation of soils contaminated with heavy metals and organic pollutants.

    PubMed

    Zhang, Xiaokai; Wang, Hailong; He, Lizhi; Lu, Kouping; Sarmah, Ajit; Li, Jianwu; Bolan, Nanthi S; Pei, Jianchuan; Huang, Huagang

    2013-12-01

    Soil contamination with heavy metals and organic pollutants has increasingly become a serious global environmental issue in recent years. Considerable efforts have been made to remediate contaminated soils. Biochar has a large surface area, and high capacity to adsorb heavy metals and organic pollutants. Biochar can potentially be used to reduce the bioavailability and leachability of heavy metals and organic pollutants in soils through adsorption and other physicochemical reactions. Biochar is typically an alkaline material which can increase soil pH and contribute to stabilization of heavy metals. Application of biochar for remediation of contaminated soils may provide a new solution to the soil pollution problem. This paper provides an overview on the impact of biochar on the environmental fate and mobility of heavy metals and organic pollutants in contaminated soils and its implication for remediation of contaminated soils. Further research directions are identified to ensure a safe and sustainable use of biochar as a soil amendment for remediation of contaminated soils.

  19. Impact of pollution caused by uranium production on soil macrofauna.

    PubMed

    Gongalsky, Konstantin B

    2003-12-01

    Thirty years of mining and milling activities of the Priargunsky Mining-Chemical Production Company (South-Eastern Siberia, Russia) have resulted in an enrichment of uranium in adjacent steppe soils by a factor of up to 600. A number of attendant pollutants (thorium, arsenic and heavy metals) also have high concentrations in the soil. To estimate the effects of this pollution on soil-living macroinvertebrates, pitfall trapping and core sampling were applied. The element composition of four beetle species was analysed. Soil macroinvertebrates had 3-37 times lower abundance and biodiversity at the contaminated sites compared with the control. Ground beetle communities at the contaminated sites were reduced compared to the control site. The concentrations of uranium and arsenic in beetles collected at the contaminated sites were 2-41 and 2-26 times higher, respectively, than at the control site. There is strong evidence that the contamination caused by uranium production has severe negative biological effects on important groups of the soil food web.

  20. Experimental assessment of the microbocenosis stability in chemically polluted soils

    NASA Astrophysics Data System (ADS)

    Sorokin, N. D.; Grodnitskaya, I. D.; Shapchenkova, O. A.; Evgrafova, S. Yu.

    2009-06-01

    Water solutions of fluorine and sulfur-containing salts of sodium—NaF, Na2SO3, and NaF + Na2SO3 (30, 150, and 300 MPC, respectively)—and salts of heavy metals—(Cu(NO3)2 · 3H2O, NiSO4, and Pb(NO3)2 (10, 25, and 50 MPC, respectively)—were applied as pollutants to dark gray forest soils of experimental plots (1 m2) in Siberian larch ( Larix sibirica Ledeb.) plantations once per growing period. The soil samples for the determination of the microbial biomass, respiration, and enzymatic activity (urease, protease, invertase, and catalase) were taken from the mineral soil layer (0-5 cm) at the beginning of the growing seasons before the application of the pollutants then in 14- to 18-day intervals every month. The fluorine and sulfur-containing compounds applied activated the respiration, lowered the enzymatic activity of the microorganisms, and decreased the microbial biomass by 1.3-2.2 times in the soils of the test plots as compared to the control one. The single application of Cu, Ni, and Pb increased the microbial biomass, while the changes in the basal respiration were compatible with its natural variability. Two months after the beginning of the experiment, all the parameters characterizing the functioning of the soil microbocenoses were restored.

  1. Grassland Degradation Alters Soil Carbon Turnover through Depth

    NASA Astrophysics Data System (ADS)

    Creamer, C.; Prober, S. M.; Chappell, A.; Farrell, M.; Baldock, J.

    2015-12-01

    Ecosystem degradation is widespread and changes in aboveground plant communities alter belowground soil processes. In Australia, grassy eucalyptus woodlands dominated by kangaroo grasses (Themeda trianda) were widely cleared during European settlement for agriculture, with only fragments remaining of this now threatened ecosystem. As remnant grassland fragments are used for livestock grazing, Themeda transitions through states of degradation, starting with red grasses (Bothriochloa spp) and then proceeding to less productive, increasingly degraded states dominated by either annual exotic weeds or native wallaby grasses (Rytidosperma spp) and spear grasses (Austrastipa spp). The aim of our experiment was to determine how soil organic matter dynamics (including erosion, root biomass, C storage and turnover) have been altered by the transition from deeply-rooted Themeda grass systems to more shallowly-rooted annual exotic weeds and wallaby/spear grass states. We sampled soils in five depth-based increments (0-5, 5-15, 15-30, 30-60, 60-100 cm) across this ecosystem transition at five sites across New South Wales, Australia. Caseium-137 analysis indicated erosion rates were similar among all ecosystems and were consistent with levels for grasslands in the region. Compared to the remnant Themeda grass systems, the degraded states had lower root biomass, lower carbon stocks and C:N ratios in the coarse fraction (> 50 μm), lower fungal : bacterial ratios, higher available phosphate, higher alkyl : O-alkyl C ratios, and faster mineralization of synthetic root-exudate carbon. All these metrics indicate the surprising finding of more microbially processed OM and faster turnover of newly added C in the degraded sites. Compared to one another, the two degraded sites differed in both C and N turnover, with the exotic weeds having higher dissolved organic N, inorganic N, and coarse fraction N, higher fine fraction C stocks, and greater microbial biomass. These differences likely

  2. Degradation and ecotoxicity of the biomedical drug artemisinin in soil.

    PubMed

    Jessing, Karina K; Cedergreen, Nina; Jensen, John; Hansen, Hans C B

    2009-04-01

    The plant Artemisia annua L. is cropped in many countries for production of the antimalarial drug artemisinin. Artemisinin is phytotoxic and has insecticidal activity. Large-scale cultivation of A. annua may cause transfer of artemisinin to soil and, hence, may affect both soil organisms and the aquatic environment if the compound is leachable. In the present study, a new method for extraction of artemisinin from soil was developed, and field concentrations and degradation kinetics of artemisinin in sandy and loamy soils were measured. The soil concentrations in a Danish A. annua field were up to 11.7 mg/kg. The degradation kinetics could be modeled as the sum of two first-order reactions, a fast initial degradation followed by a reaction that was 11- to 25-fold slower. It took at least 35 d before artemisinin could not be detected (<0.36 mg/kg) at 20 degrees C, classifying artemisinin as being relatively persistent in the environment. Combined with its water solubility of 49.7 +/- 3.7 mg/L, this makes it potentially leachable. In soil, artemisinin repelled the earthworm (Eisenia fetida; the 10 and 50% effect concentrations [EC10s and EC50s, respectively] were 5.24 +/- 2.64 and 21.57 +/- 4.73 mg/kg, respectively) and inhibited growth of lettuce (Lactuca sativa L.; EC50, 2.48 mg/kg). Springtails (Folsomia candida) were not affected in the tested concentration range of 1 to 100 mg/kg. Artemisinin had toxicity to the freshwater algae (Pseudokirchneriella subcapitata; EC50, 0.24 +/- 0.01 mg/L) and duckweed (Lemna minor; EC50, 0.19 +/- 0.03 mg/L) similar to that of the commercial herbicide atrazine. Based on the presented data, the risks of adverse environmental effects because of cultivation of A. annua are high and comparable to those when using commercial pesticides.

  3. Assessing and monitoring soil erosion and land degradation in Malta

    NASA Astrophysics Data System (ADS)

    Symeonakis, Elias; Brearley, James

    2017-04-01

    The United Nations Convention to Combat Desertification (UNCCD) identifies the Mediterranean as one of the most seriously affected by land degradation and desertification (LDD) regions in the World. LDD is a complex process related with a multitude of biogeographical and socioeconomic parameters and is often assessed using proxies or indicators. One of the most important indicators of LDD is soil erosion. Here, we assess the evolution of soil erosion and LDD in the Mediterranean islands of Malta between 1986 and 2002. Soil erosion is estimated using the Revised Soil Loss Equation (RUSLE). For the assessment of LDD, we employ a modification of the Environmentally Sensitive Area Index (ESAI) methodology with Landsat imagery and ancillary GIS datasets. We incorporate 4 vegetation-related indicators, 3 climate-related, 5 soil-related and 3 socio-economic ones in the final assessment of the evolution of LDD. Results show that there has been an increase in soil erosion rates and in the sensitivity to LDD in the areas of San Pawl il-Bahar and Il-Mizieb most likely due to the transition from agricultural use to Mediterranean shrubs. Also, almost the entire country is flagged as belonging to the 'Fragile' and 'Critical' ESAI classes. It is clear that soil erosion and LDD mitigation measures are necessary, especially in the most critical (i.e. 'C3') areas which occupy 10% of Malta.

  4. Visible and infrared spectroscopy to evaluate soil quality in degraded sites: an applicative study in southern Italy

    NASA Astrophysics Data System (ADS)

    Ancona, Valeria; Matarrese, Raffaella; Salvatori, Rosamaria; Salzano, Roberto; Regano, Simona; Calabrese, Angelantonio; Campanale, Claudia; Felice Uricchio, Vito

    2014-05-01

    Land degradation processes like organic matter impoverishment and contamination are growing increasingly all over the world due to a non-rational and often sustainable spread of human activities on the territory. Consequently the need to characterize and monitor degraded sites is becoming very important, with the aim to hinder such main threats, which could compromise drastically, soil quality. Visible and infrared spectroscopy is a well-known technique/tool to study soil properties. Vis-NIR spectral reflectance, in fact, can be used to characterize spatial and temporal variation in soil constituents (Brown et al., 2006; Viscarra Rossel et al., 2006), and potentially its surface structure (Chappell et al., 2006, 2007). It is a rapid, non-destructive, reproducible and cost-effective analytical method to analyse soil properties and therefore, it can be a useful method to study land degradation phenomena. In this work, we present the results of proximal sensing investigations of three degraded sites (one affected by organic and inorganic contamination and two affected by soil organic matter decline) situated southern Italy close to Taranto city (in Apulia Region). A portable spectroradiometer (ASD-FieldSpec) was used to measure the reflectance properties in the spectral range between 350-2500 nm of the soil, in the selected sites, before and after a recovery treatment by using compost (organic fertilizer). For each measurement point the soil was sampled in order to perform chemical analyses to evaluate soil quality status. Three in-situ campaigns have been carried out (September 2012, June 2013, and September 2013), collecting about 20 soil samples for each site and for each campaign. Chemical and spectral analyses have been focused on investigating soil organic carbon, carbonate content, texture and, in the case of polluted site, heavy metals and organic toxic compounds. Statistical analyses have been carried out to test a prediction model of different soil quality

  5. Physiological and Transcriptome Response of the Polycyclic Aromatic Hydrocarbon Degrading Novosphingobium sp. LH128 after Inoculation in Soil.

    PubMed

    Fida, Tekle Tafese; Moreno-Forero, Silvia K; Breugelmans, Philip; Heipieper, Hermann J; Röling, Wilfred F M; Springael, Dirk

    2017-02-07

    Soil bioaugmentation involves the inoculation of pollutant-degrading bacteria to accelerate pollutant degradation. Often the inoculum shows a dramatic decrease in Colony Forming Units (CFU) upon soil inoculation but this behavior is not well-understood. In this study, the physiology and transcriptomic response of a GFP tagged variant of Novosphingobium sp. LH128 was examined after inoculation into phenanthrene spiked soil. Four hours after inoculation, strain LH128-GFP showed about 99% reduction in CFU while microscopic counts of GFP-expressing cells were identical to the expected initial cell density, indicating that the reduction in CFU number is explained by cells entering into a Viable But Non-Culturable (VBNC)-like state and not by cell death. Transcriptome analysis showed a remarkably higher expression of phenanthrene degradation genes 4 h after inoculation, compared to the inoculum suspension concomitant with an increased expression of genes involved in stress response. This indicates that the cells were active in phenanthrene degradation while experiencing stress. Between 4 h and 10 days, CFU numbers increased to numbers comparable to the inoculated cell density. Our results suggest that strain LH128-GFP enters a VBNC-like state upon inoculation into soil but is metabolically active and that VBNC cells should be taken into account in evaluating bioaugmentation approaches.

  6. Urban soil pollution and the playfields of small children

    NASA Astrophysics Data System (ADS)

    Jartun, M.; Ottesen, R. T.; Steinnes, E.

    2003-05-01

    The chemical composition of urban surface soil in Tromsø, northern Norway has been mapped to describe the environmental load of toxic elements in different parts of the city. Surface soil samples were collected from 275 locations throughout the city center and nearby suburban areas. Natural background concentrations were determined in samples of the local bedrock. Surface soil in younger, suburban parts of the city shows low concentrations of heavy metals, reflecting the local geochemistry. The inner and older parts of the city are generally polluted with lead (Pb), zinc (Zn) and tin (Sn). The most important sources of this urban soil pollution are probably city fires, industrial and domestic waste, traffic, and shipyards. In this paper two different approaches have been used. First, as a result of the general mapping, 852 soil and sand samples from kindergartens and playgrounds were analyzed. In this study concentrations of arsenic (As) up to 1800ppm were found, most likely due to the extensive use of CCA (copper, chromium, arsenic) impregnated wood in sandboxes and other playground equipment. This may represent a significant health risk especially to children having a high oral intake of contaminated sand and soil. Secondly a pattern of tin (Sn) concentrations was found in Tromsøcity with especially high values near shipyards. Further investigation indicated that this pattern most probably reflected the use of the highty toxic tributyltin (TBT). Thus détermination of total Sn in surface soils could be a cost-effective way to localize sources of TBT contamination in the environment.

  7. Water and soil pollution in vineyards of central Thailand.

    PubMed

    Joannon, G; Poss, R; Korpraditskul, R; Brunet, D; Boonsook, P

    2001-01-01

    Very intensive cultivation systems have been developed in the delta of the Chao Phraya River for about a century. The objective of the study was to determine the fate of the fertilisers and pesticides applied to vineyards grown on raised beds. Water samples were collected from the outlet of a vineyard to determine the discharge of pollutants in the canal. The accumulation of elements in the soil was investigated by analysing soil samples from different fields. Fertilisation was estimated at 670 kg N, 300 kg P, and 560 kg K year(-1) ha(-1). Insecticides and fungicides were applied every four days on average, using up to 23 different molecules. Little N and no P were discharged in the canals in solution and discharge in suspension was minor. Pesticides were detected in 36% of the water samples. The topsoil contained 1600 mg kg(-1) Bray II P, 936 mg kg(-1) exchangeable K, 170 mg kg(-1) total Cu, and 167 mg kg(-1) total Zn. Pesticides were detected in 62% of the fruits after peeling. Overuse of fertilisers did not lead to water pollution, but overuse of pesticides resulted in pollution of the water bodies and of the fruits. Most applied elements accumulated in the soil, resulting in high values of P, K, Cu, and Zn.

  8. Differential Degradation and Detoxification of an Aromatic Pollutant by Two Different Peroxidases

    PubMed Central

    Alneyadi, Aysha Hamad; Shah, Iltaf; AbuQamar, Synan F.; Ashraf, Syed Salman

    2017-01-01

    Enzymatic degradation of organic pollutants is a new and promising remediation approach. Peroxidases are one of the most commonly used classes of enzymes to degrade organic pollutants. However, it is generally assumed that all peroxidases behave similarly and produce similar degradation products. In this study, we conducted detailed studies of the degradation of a model aromatic pollutant, Sulforhodamine B dye (SRB dye), using two peroxidases—soybean peroxidase (SBP) and chloroperoxidase (CPO). Our results show that these two related enzymes had different optimum conditions (pH, temperature, H2O2 concentration, etc.) for efficiently degrading SRB dye. High-performance liquid chromatography and liquid chromatography –mass spectrometry analyses confirmed that both SBP and CPO transformed the SRB dye into low molecular weight intermediates. While most of the intermediates produced by the two enzymes were the same, the CPO treatment produced at least one different intermediate. Furthermore, toxicological evaluation using lettuce (Lactuca sativa) seeds demonstrated that the SBP-based treatment was able to eliminate the phytotoxicity of SRB dye, but the CPO-based treatment did not. Our results show, for the first time, that while both of these related enzymes can be used to efficiently degrade organic pollutants, they have different optimum reaction conditions and may not be equally efficient in detoxification of organic pollutants. PMID:28335468

  9. [Degradation of phthalate esters in soil and the effects on soil enzyme activities].

    PubMed

    Zhang, Jian; Shi, Yi-Jing; Cui, Yin; Xie, Hui-Jun; Wang, Wen-Xing

    2010-12-01

    Phthalate esters (PAEs) are a kind of widespread toxic organic compounds in the environment. We discussed the different degradation rate of four kinds of PAEs in the soil and its impact on different soil enzyme activities. We used GC-MS methods to determine the concentration of PAEs in soil. The results showed that soil microorganisms play a major role in the degradation of PAEs. The biodegradation diagram of PAEs was accord with first-order kinetics equation. And the shorter carbon chain, the better degradation efficiency. With the high concentration of PAE30, DnOP, which has long carbon chain, the degradation efficiency is lower than that of PAE1 and PAE10, only 73% was degraded after 40 days. We use standard methods to determine the matrix enzyme activities, after adding the PAEs into soil, beta-glucosidase, phosphatase, urease, protease activity have changed. Phosphatase activity decreased at first and then increased, beta-glucosidase activity decreased slowly, protease activity increased at first and then decreased, the activity of urease increased gradually. After 20 days, except for beta-glucosidase activity continued decreasing, the activities of others enzyme recovered gradually, and higher than the control group.

  10. Degradation and Sorption of Imidacloprid in Dissimilar Surface and Subsurface Soils

    USDA-ARS?s Scientific Manuscript database

    Degradation and sorption/desorption are important processes affecting the leaching of pesticides through soil. Once pesticides move past the surface soil layers, subsurface soil physical, chemical, and biological properties significantly affect pesticide fate and the potential for groundwater contam...

  11. Polycyclic aromatic hydrocarbons pollution effect on soil biological activity in the anthropogenic contaminated area

    NASA Astrophysics Data System (ADS)

    Batukaev, Abdulmalik; Sushkova, Svetlana; Minkina, Tatiana; Antonenko, Elena; Salamova, Anzhelika; Gimp, Alina; Deryabkina, Irina

    2017-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are one of the most significant environmental contaminants with mutagenic and carcinogenic properties to all living organisms. The changes in microbial community structure in technogenic polluted soil may be used as tools for predicting and monitoring natural degradation and for search the most effective and appropriate pathways of bioremediation. The present study is aimed to research the biological activity of the soil in the emission zone of Novocherkassk Power station (NPs) (Russia) polluted by PAHs in 2015. The NPs is one of the largest thermal power stations in the south of Russia burning low-quality coal appurtenant the enterprises of I hazardous class. Monitoring plots were located on virgin or no-till fallow areas and not subject to the sanitary-protection zone of the NPs. Soil samples were taken from a depth of 0- to 20-cm, because the major part of PAHs are accumulated in the surface soil layer. The soils of the plots mainly include Chernozems Calcic (plots 1, 4, 5, 7, 9 and 10), Phaeozems Haplic (plots 3, 6, 8 and 11) Fluvisols Umbric (plots 2 and 12). In the soil of 12 monitoring plots located around NPs there were determined the main enzymes, abundance of soil bacteria and 17 priority PAHs. PAHs extraction from soil was performed by new developed ecologically clean method of subcritical water extraction without organic solvents (Sushkova et al., 2015). The level of PAHs around NPs is high at the nearest to factory monitoring plots situated at distance 1,0-1,2 km and reaches from 1600,1±14,7 up to 373,6±7,1 mkg/kg in the 20-cm soil layer. Gradually decrease of PAHs contamination is observed while increasing the distance from the NPs. The level of highmolecular PAHs (4-6 aromatic rings) exceeds the level of lowmolecular (2-3 aromatic rings) PAHs in all monitoring plots situated though the prevailing wind direction from NPs. The close correlations were found between PAHs content and biological activity parameters

  12. Can biochar in combination with compost improve degraded soils?

    NASA Astrophysics Data System (ADS)

    Friesl-Hanl, Wolfgang; Zehetner, Franz; Dunst, Gerald; Wagner, Mario; Puschenreiter, Markus; Karer, Jasmin; Soja, Gerhard

    2016-04-01

    As global demand for agricultural commodities is growing, the use and improvement of degraded land could at least partly meet this demand. Based on the Renewable Energy Directive 2009/28/EC (RED) which endorses the use of degraded land for biomass production on the one hand, and the emerging conflict of the 4 F's (food, feed, fiber and fuel production) on the other hand, the application of biochar to ameliorate degraded land could be a strategy to improve the productivity of soils on marginal agricultural land. The aim of our study was to investigate the effects of biochar/compost mixtures (w/w; 50/50) on two agricultural soils low in organic matter - one sandy, the other clayey. The suitability of the biochar/compost-amended (BC) soils for renewable biomass production using maize or Miscanthus was tested in the field. We conducted two field experiments with different treatments based on the results of previous pot experiments with the same soils. The following treatments were applied: • Co … Control (no BC but fertilized with (NH4)2SO4 corresponding to T3) • T1 … 1 % BC • T2 … 0.5 % BC + 175 kg N ha-1 • T3 … 1 % BC + 350 kg N ha-1 The treatments influenced water holding capacity (WHC), organic carbon content (Corg) in soil and biomass productivity (BM). WHC increased significantly upon 3 % BC addition in the previous pot experiment, but not significantly upon 1 % addition in the field (T1, T3). Due to heterogeneity in the field Corg did not show significant differences between treatments. The two test soils responded differently for BM productivity. Miscanthus (perennial) grown on sandy Eschenau soil was not influenced by the treatments in 2013 but showed a positive reaction trend in 2014. Miscanthus will need at least one further growing season to show its full yield potential. Maize (annual) grown on clayey Kaindorf soil increased BM significantly 2013 upon T3 but not in 2014 due to erosion events on sloping terrain. Keywords: Soil quality

  13. Electrokinetic delivery of persulfate to remediate PCBs polluted soils: Effect of different activation methods.

    PubMed

    Fan, Guangping; Cang, Long; Gomes, Helena I; Zhou, Dongmei

    2016-02-01

    Persulfate-based in-situ chemical oxidation (ISCO) for the remediation of organic polluted soils has gained much interest in last decade. However, the transportation of persulfate in low-permeability soil is very low, which limits its efficiency in degrading soil pollutants. Additionally, the oxidation-reduction process of persulfate with organic contaminants takes place slowly, while, the reaction will be greatly accelerated by the production of more powerful radicals once it is activated. Electrokinetic remediation (EK) is a good way for transporting persulfate in low-permeability soil. In this study, different activation methods, using zero-valent iron, citric acid chelated Fe(2+), iron electrode, alkaline pH and peroxide, were evaluated to enhance the activity of persulfate delivered by EK. All the activators and the persulfate were added in the anolyte. The results indicated that zero-valent iron, alkaline, and peroxide enhanced the transportation of persulfate at the first stage of EK test, and the longest delivery distance reached sections S4 or S5 (near the cathode) on the 6th day. The addition of activators accelerated decomposition of persulfate, which resulted in the decreasing soil pH. The mass of persulfate delivered into the soil declined with the continuous decomposition of persulfate by activation. The removal efficiency of PCBs in soil followed the order of alkaline activation > peroxide activation > citric acid chelated Fe(2+) activation > zero-valent iron activation > without activation > iron electrode activation, and the values were 40.5%, 35.6%, 34.1%, 32.4%, 30.8% and 30.5%, respectively. The activation effect was highly dependent on the ratio of activator and persulfate.

  14. Ecological restoration of mine degraded soils, with emphasis on metal contaminated soils.

    PubMed

    Wong, M H

    2003-02-01

    This paper reviews the ecological aspects of mined soil restoration, with special emphasis on maintaining a long-term sustainable vegetation on toxic metal mine sites. The metal mined soils are man-made habitats which are very unstable and will become sources of air and water pollution. Establishment of a vegetation cover is essential to stabilize the bare area and to minimize the pollution problem. In addition to remediate the adverse physical and chemical properties of the sites, the choice of appropriate vegetation will be important. Phytostabilization and phytoextraction are two common phytoremediation techniques in treating metal-contaminated soils, for stabilizing toxic mine spoils, and the removal of toxic metals from the spoils respectively. Soil amendments should be added to aid stabilizing mine spoils, and to enhance metal uptake accordingly.

  15. Sorption, transport and biodegradation - An insight into bioavailability of persistent organic pollutants in soil.

    PubMed

    Ren, Xiaoya; Zeng, Guangming; Tang, Lin; Wang, Jingjing; Wan, Jia; Liu, Yani; Yu, Jiangfang; Yi, Huan; Ye, Shujing; Deng, Rui

    2017-08-24

    Contamination of soils with persistent organic pollutants (POPs), such as organochlorine pesticide, polybrominated diphenyl ethers, halohydrocarbon, polycyclic aromatic hydrocarbons (PAHs) is of increasing concern. Microbial degradation is potential mechanism for the removal of POPs, but it is often restricted by low bioavailability of POPs. Thus, it is important to enhance bioavailability of POPs in soil bioremediation. A series of reviews on bioavailability of POPs has been published in the past few years. However, bioavailability of POPs in relation to soil organic matter, minerals and soil microbes has been little studied. To fully understand POPs bioavailability in soil, research on interactions of POPs with soil components and microbial responses in bioavailability limitation conditions are needed. This review focuses on bioavailability mechanisms of POPs in terms of sorption, transport and microbial adaptation, which is particularly novel. In consideration of the significance of bioavailability, further studies should investigate the influence of various bioremediation strategies on POPs bioavailability. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Solarization and biosolarization using organic wastes for the bioremediation of soil polluted with terbuthylazine and linuron residues.

    PubMed

    Fenoll, José; Hellín, Pilar; Flores, Pilar; Lacasa, Alfredo; Navarro, Simón

    2014-10-01

    Strategies for remediation of polluted soils are needed to accelerate the degradation and natural attenuation of pesticides. This study was conducted to assess the effect of solarization (S) and biosolarization (BS) during the summer season using organic wastes (composted sheep manure and sugar beet vinasse) for the bioremediation of soil containing residues of terbuthylazine and linuron. The results showed that both S and BS enhanced herbicide dissipation rates compared with the non-disinfected control, an effect which was attributed to the increased soil temperature and organic matter. Linuron showed similar behavior under S and BS conditions. However, terbuthylazine was degraded to a greater extent in the biosolarization experiment using sugar beet vinasse than in the both the solarization and biosolarization experiments using composted sheep manure treatments. The main organic intermediates detected during the degradation of terbuthylazine and linuron were identified, enabling the main steps of degradation to be proposed. The results confirm that both S and BS techniques can be considered as a remediation tools for polluted soils containing these herbicides.

  17. Impact of compost process conditions on organic micro pollutant degradation during full scale composting.

    PubMed

    Sadef, Yumna; Poulsen, Tjalfe Gorm; Bester, Kai

    2015-06-01

    Knowledge about the effects of oxygen concentration, nutrient availability and moisture content on removal of organic micro-pollutants during aerobic composting is at present very limited. Impact of oxygen concentration, readily available nitrogen content (NH4(+), NO3(-)), and moisture content on biological transformation of 15 key organic micro-pollutants during composting, was therefore investigated using bench-scale degradation experiments based on non-sterile compost samples, collected at full-scale composting facilities. In addition, the adequacy of bench-scale composting experiments for representing full-scale composting conditions, was investigated using micro-pollutant concentration measurements from both bench- and full-scale composting experiments. Results showed that lack of oxygen generally prevented transformation of organic micro-pollutants. Increasing readily available nitrogen content from about 50 mg N per 100 g compost to about 140 mg N per 100 g compost actually reduced micro-pollutant transformation, while changes in compost moisture content from 50% to 20% by weight, only had minor influence on micro-pollutant transformation. First-order micro-pollutant degradation rates for 13 organic micro-pollutants were calculated using data from both full- and bench-scale experiments. First-order degradation coefficients for both types of experiments were similar and ranged from 0.02 to 0.03 d(-1) on average, indicating that if a proper sampling strategy is employed, bench-scale experiments can be used to represent full-scale composting conditions.

  18. Catalytic degradation of the soil fumigant 1,3-dichloropropene in aqueous biochar slurry.

    PubMed

    Qin, Jiaolong; Cheng, Yuxiao; Sun, Mingxing; Yan, Lili; Shen, Guoqing

    2016-11-01

    Biochar has been explored as a cost-effective sorbent of contaminants, such as soil fumigant. However, contaminant-loaded biochar probably becomes a source of secondary air pollution. In this study, biochars developed from cow manure and rice husk at 300°C or 700°C were used to investigate the catalytic degradation of the soil fumigant 1,3-dichloropropene (1,3-D) in aqueous biochar slurry. Results showed that the adsorption of 1,3-D on the biochars was influenced by Langmuir surface monolayer adsorption. The maximum adsorption capacity of cow manure was greater than that of rice husk at the same pyrolysis temperature. Batch experiments revealed that 1,3-D degradation was improved in aqueous biochar slurry. The most rapid 1,3-D degradation occurred on cow manure-derived biochar produced at 300°C (C-300), with t1/2=3.47days. The degradation efficiency of 1,3-D on C-300 was 95.52%. Environmentally persistent free radicals (EPFRs) in biochars were detected via electron paramagnetic resonance (EPR) techniques. Dissolved organic matter (DOM) and hydroxyl radical (·OH) in biochars were detected by using a fluorescence spectrophotometer coupled with a terephthalic acid trapping method. The improvement of 1,3-D degradation efficiency may be attributed to EPFRs and DOM in aqueous biochar slurry. Our results may pose implications in the development of effective reduction strategies for soil fumigant emission with biochar. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Effect of soil pollution on water for mixing of concrete

    NASA Astrophysics Data System (ADS)

    Muñoz, M. Cecilia Soto; Tapia Alvarez, Carolina; Decinti Weiss, Alejandra; Zamorano Vargas, Macarena; Corail Sanchez, Camila; Hurtado Nuñez, Camilo; Guzman Hermosilla, Matías; Pardo Fabregat, Francisco; Vidal, Manuel Miguel Jordan; Borras, Jaume Bech; Roca, Nuria

    2016-04-01

    ISO 12439, in addition to chemical and physical requirements, establishes maximum levels for harmful substances that may be present in the mixing water of concrete, when they come from natural sources from contaminated soils. These harmful substances considered in the ISO are sugars, phosphates (P2O5), nitrate (NO3-), lead (P2+) and zinc (Zn2+). As an alternative to the maximum values, ISO verifies the effect of these substances in water from contaminated soils. This measurement is made on the effect on the mechanical strength of the concrete (compression at 7 and 28 days) and the setting times (start and end setting). This paper presents the results obtained on samples of concrete made with smaller, similar and more content to the maximum levels set by ISO 12439 are presented. The results establish that in the case of nitrate, a substance present in many contaminated soils margins resistance variation or setting times allowed by ISO 12439 are not met. Finally, it is concluded that in case of presence of these pollutants should be performed strength tests and setting times before authorizing the use of water. Keywords: Harmful substances, contaminated soils, water pollution.

  20. Hycrest crested wheatgrass accelerates the degradation of pentachlorophenol in soil

    NASA Technical Reports Server (NTRS)

    Ferro, A. M.; Sims, R. C.; Bugbee, B.

    1994-01-01

    We investigated the effects of vegetation on the fate of pentachlorophenol (PCP) in soil using a novel high-flow sealed test system. Pentachlorophenol has been widely used as a wood preservative, and this highly toxic biocide contaminates soil and ground water at many sites. Although plants are known to accelerate the rates of degradation of certain soil contaminants, this approach has not been thoroughly investigated for PCP. The fate of [14C]PCP, added to soil at a concentration of 100 mg/kg, was compared in three unplanted and three planted systems. The plant used was Hycrest, a perennial, drought-tolerant cultivar of crested wheatgrass [Agropyron desertorum (Fischer ex Link) Schultes]. The flow-through test system allowed us to maintain a budget for 14C-label as well as monitor mineralization (breakdown to 14CO2) and volatilization of the test compound in a 155-d trial. In the unplanted systems, an average of 88% of the total radiolabel remained in the soil and leachate and only 6% was mineralized. In the planted system, 33% of the radiolabel remained in the soil plus leachate, 22% was mineralized, and 36% was associated with plant tissue (21% with the root fraction and 15% with shoots). Mineralization rates were 23.1 mg PCP mineralized kg-1 soil in 20 wk in the planted system, and for the unplanted system 6.6 mg PCP kg-1 soil for the same time period. Similar amounts of volatile organic material were generated in the two systems (1.5%). Results indicated that establishing crested wheatgrass on PCP-contaminated surface soils may accelerate the removal of the contaminant.

  1. Hycrest crested wheatgrass accelerates the degradation of pentachlorophenol in soil

    NASA Technical Reports Server (NTRS)

    Ferro, A. M.; Sims, R. C.; Bugbee, B.

    1994-01-01

    We investigated the effects of vegetation on the fate of pentachlorophenol (PCP) in soil using a novel high-flow sealed test system. Pentachlorophenol has been widely used as a wood preservative, and this highly toxic biocide contaminates soil and ground water at many sites. Although plants are known to accelerate the rates of degradation of certain soil contaminants, this approach has not been thoroughly investigated for PCP. The fate of [14C]PCP, added to soil at a concentration of 100 mg/kg, was compared in three unplanted and three planted systems. The plant used was Hycrest, a perennial, drought-tolerant cultivar of crested wheatgrass [Agropyron desertorum (Fischer ex Link) Schultes]. The flow-through test system allowed us to maintain a budget for 14C-label as well as monitor mineralization (breakdown to 14CO2) and volatilization of the test compound in a 155-d trial. In the unplanted systems, an average of 88% of the total radiolabel remained in the soil and leachate and only 6% was mineralized. In the planted system, 33% of the radiolabel remained in the soil plus leachate, 22% was mineralized, and 36% was associated with plant tissue (21% with the root fraction and 15% with shoots). Mineralization rates were 23.1 mg PCP mineralized kg-1 soil in 20 wk in the planted system, and for the unplanted system 6.6 mg PCP kg-1 soil for the same time period. Similar amounts of volatile organic material were generated in the two systems (1.5%). Results indicated that establishing crested wheatgrass on PCP-contaminated surface soils may accelerate the removal of the contaminant.

  2. Long-term diffuse phosphorus pollution dynamics under the combined influence of land use and soil property variations.

    PubMed

    Huang, Haobo; Ouyang, Wei; Wu, Haotian; Liu, Hongbin; Andrea, Critto

    2017-02-01

    Analyses of the spatial-temporal distribution of diffuse pollution in agricultural regions are essential to the sustained management of water resources. Although nutrients, such as phosphorus fertilizers, can promote crop growth while improving soil fertility, excessive nutrient inputs can produce diffuse pollution, which may results in water quality degradation. The objective of this paper is to employ the SWAT (Soil and Water Assessment Tool) to estimate diffuse P effects on temporal and spatial distributions for a typical agricultural watershed and to identify the conjunct and independent influences of long-term land use and soil properties variation on diffuse P. With the validated model, the four-period simulation results (from 1979 to 2009) indicate that land use changes from agricultural development increased diffuse P yields. However, regarding updated soil properties, no significant differences of P yield were found between 1979 and 2009, demonstrating that impact of the cropland expansion were naturalized with soil property variations. An F-test was employed to assess the essentiality of all of the variables examined during the simulation period, and the test results indicated that diffuse P loading was more sensitive to soil properties than to land use. Before the P pollution control project about the land use optimization planning, it is more effective to distinguish the impacts of land use and soil properties. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Construction of PAH-degrading mixed microbial consortia by induced selection in soil.

    PubMed

    Zafra, German; Absalón, Ángel E; Anducho-Reyes, Miguel Ángel; Fernandez, Francisco J; Cortés-Espinosa, Diana V

    2017-04-01

    Bioremediation of polycyclic aromatic hydrocarbons (PAHs)-contaminated soils through the biostimulation and bioaugmentation processes can be a strategy for the clean-up of oil spills and environmental accidents. In this work, an induced microbial selection method using PAH-polluted soils was successfully used to construct two microbial consortia exhibiting high degradation levels of low and high molecular weight PAHs. Six fungal and seven bacterial native strains were used to construct mixed consortia with the ability to tolerate high amounts of phenanthrene (Phe), pyrene (Pyr) and benzo(a)pyrene (BaP) and utilize these compounds as a sole carbon source. In addition, we used two engineered PAH-degrading fungal strains producing heterologous ligninolytic enzymes. After a previous selection using microbial antagonism tests, the selection was performed in microcosm systems and monitored using PCR-DGGE, CO2 evolution and PAH quantitation. The resulting consortia (i.e., C1 and C2) were able to degrade up to 92% of Phe, 64% of Pyr and 65% of BaP out of 1000 mg kg(-1) of a mixture of Phe, Pyr and BaP (1:1:1) after a two-week incubation. The results indicate that constructed microbial consortia have high potential for soil bioremediation by bioaugmentation and biostimulation and may be effective for the treatment of sites polluted with PAHs due to their elevated tolerance to aromatic compounds, their capacity to utilize them as energy source. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Distribution of Heavy Metal Pollution in Surface Soil Samples in China: A Graphical Review.

    PubMed

    Duan, Qiannan; Lee, Jianchao; Liu, Yansong; Chen, Han; Hu, Huanyu

    2016-09-01

    Soil pollution in China is one of most wide and severe in the world. Although environmental researchers are well aware of the acuteness of soil pollution in China, a precise and comprehensive mapping system of soil pollution has never been released. By compiling, integrating and processing nearly a decade of soil pollution data, we have created cornerstone maps that illustrate the distribution and concentration of cadmium, lead, zinc, arsenic, copper and chromium in surficial soil across the nation. These summarized maps and the integrated data provide precise geographic coordinates and heavy metal concentrations; they are also the first ones to provide such thorough and comprehensive details about heavy metal soil pollution in China. In this study, we focus on some of the most polluted areas to illustrate the severity of this pressing environmental problem and demonstrate that most developed and populous areas have been subjected to heavy metal pollution.

  5. Hg soil pollution around the Flix chlor-alkali plant

    NASA Astrophysics Data System (ADS)

    Esbrí, José Maria; López-Berdoces, Miguel Angel; Martínez-Coronado, Alba; Fernández-Calderon, Sergio; Díez, Sergi; León Higueras, Pablo

    2014-05-01

    Main mercury consumer in industrialized countries is the chlor-alkali industry. In Spain, this industry declares 2.54 tons of mercury emissions to the atmosphere per year, but the losses of mercury in this industrial process seem to be higher than this. In the next 15 years, these industries are going to make a technology change to a free mercury based technology. This study has been applied to the Flix (Tarragona, NE Spain) plant, located very near the Ebro River. Local industrial activity started in the late 18th Century, being the first Spanish industrial precinct in activity. Technology used in this plant is obsolete, and produces important emissions to the atmosphere. Besides, it has also produced an important pollution problem in the Ebro River. The aim of this work is the characterization of mercury soil pollution around the oldest chlor-alkali plant (CAP), actually in process of decommissioning. For this porpoises, we provided data of mercury in soils and in olive oil leaves, in order to assess the extent of this pollution, and the consequences in terms of transferring to local agricultural biota. We present data from two soils geochemistry surveys, one centered in the general area, and a second one centered in an anomalous area identified by the first survey, at the Ebro margins downstream the town area. A total of 126 surface soil samples were taken and analyzed for total mercury by means of a Lumex RA-915+ device with RP- 91C pyrolysis attachment. Soil-plant transfer was studied based on mercury contents in olive leaves, the most ubiquitous plant species in the area; these biological samples were thoroughly clean and freeze-dried before its total mercury analysis in a Lumex RA-915+ device with its RP-91c pyrolysis attachment. Mercury contents in soils reach maximum levels in the vicinity of CAP (495 mg kg-1), much higher than baseline levels found in the area (0.18 mg kg-1, in average). These polluted soils are located near CAP and the riverbanks of Ebro

  6. [Sorption and microbial degradation of glyphosphate in soil suspensions].

    PubMed

    Shushkova, T V; Vasil'eva, G K; Ermakova, I T; Leont'evskiĭ, A A

    2009-01-01

    Sorption and microbial destruction of glyphosphate, the active agent of the herbicide Groundbio, in suspensions of sod-podzolic and gray forest soils has been studied. According to the values of the adsorptive capacity (3560 and 8200 mg/kg, respectively) and the Freundlich constants (Kf, 15.6 and 18.7, respectively), these soils had a relatively high sorption capacity as related to the herbicide. Sorbed glyphosphate is represented by extractable and bound (inextractable) fractions. After long-term incubation of sterile suspensions, the ratio of these fractions reached 2 : 1 for sod-podzolic soil and 1 : 1 for gray forest soil. Inoculation of a native suspension of sod-podzolic soil with cells of a selected degrader strain Ochrobactum anthropi GPK 3 resulted in a 25.4% decrease in the total glyphosphate content (dissolved and extractable), whereas in a noninoculated suspension, the loss did not exceed 5.5%. The potential for the use of a selected bacterial strain for intensification of the glyphosphate destruction processes in soil systems is demonstrated for the first time.

  7. Degradation of atrazine in soil through induced photocatalytic processes

    SciTech Connect

    Pelizzetti, E. ); Carlin, V.; Maurino, V.; Minero, C.; Dolci, M. ); Marchesini, A. )

    1990-08-01

    The authors observed photocatalytic degradation of atrazine in the presence of semiconductor metal oxide particulates (TiO{sub 2}, ZnO) suspended in aqueous solution under simulated sunlight irradiation. The half-life for the process is ca. 5 and 80 min for TiO{sub 2} and ZnO, respectively (at an initial atrazine concentration of 25 mg/liter with 0.5 g of semiconductor per liter and with a photon flux of 3 {times} 10{sup {minus}5} einstein/min, and over a cell cross section of 4 cm{sup 2}). The authors investigated the catalytic activity of different soils. The weak photocatalytic activity of the soils (2 g/liter) is dramatically increased by the addition of 0.5 g of the semiconductor per liter. Half-lives are 10 to 40 minutes, depending on the nature of the soil.

  8. Biomonitoring insecticide pollution using non-target soil microarthropods.

    PubMed

    Joy, V C; Pramanik, R; Sarkar, K

    2005-07-01

    The scope of biomonitoring insecticide pollution in soil is discussed with the help of field and laboratory findings on the density, prey-predator ratio and fecundity of non-target microarthropod fauna. Field experiments were conducted in small plots with mustard, wheat and lady's finger crops and insecticides namely heptachlor 20EC (3.25 kg ai/ha = 16.25 lit/ha) and endosulfan 35EC (0.875 kg ai/ha = 2.5 lit/ha) applied at the seedling stages. Soil microarthropod population estimated at fortnightly intervals in the treated and untreated control plots revealed a general trend of adverse effect of the insecticides, prominently on the density and relative abundance of major prey groups like Collembola and Acari leading to notable decline in prey-predator ratio. Comparison of the percentage reductions of major taxonomic and trophic groups between pre-treatment and post-treatment intervals also demonstrated the ill effect of both heptachlor and endosulfan, notably on Collembola and the prey category. In the laboratory the survival success and fecundity of Cyphoderus javanus (Collembola) and Archegozetes longisetosus (Acari) were compared by exposing freshly emerged adults to sub-lethal concentrations of heptachlor and endosulfan for varying durations. The untreated control sets recorded high fecundity for both C. javanus and A. longisetosus, but chronic toxicity of the insecticides on adults confined to the treated soil resulted into very low fecundity. Even short duration exposure to heptachlor and endosulfan treated soil for 24 or 72 hours only was found to delay the egg-laying and decrease the fecundity of both the species. It is concluded that population responses and reproductive sensitivity in non-target soil microarthropods are potential eco-toxicological parameters for detecting pesticide pollution in soil and for ecological health assessment since the results are based on the bioactivity of toxicants.

  9. Construction and applications of DNA probes for detection of polychlorinated biphenyl-degrading genotypes in toxic organic-contaminated soil environments

    SciTech Connect

    Walia, S.; Khan, A.; Rosenthal, N. )

    1990-01-01

    Several DNA probes for polychlorinated biphenyl (PCB)-degrading genotypes were constructed from PCB-degrading bacteria. These laboratory-engineered DNA probes were used for the detection, enumeration, and isolation of specific bacteria degrading PCBs. Dot blot analysis of purified DNA from toxic organic chemical-contaminated soil bacterial communities showed positive DNA-DNA hybridization with a 32P-labeled DNA probe (pAW6194, cbpABCD). Less than 1% of bacterial colonies isolated from garden topsoil and greater than 80% of bacteria isolated from PCB-contaminated soils showed DNA homologies with 32P-labeled DNA probes. Some of the PCB-degrading bacterial isolates detected by the DNA probe method did not show biphenyl clearance. The DNA probe method was found to detect additional organisms with greater genetic potential to degrade PCBs than the biphenyl clearance method did. Results from this study demonstrate the usefulness of DNA probes in detecting specific PCB-degrading bacteria, abundance of PCB-degrading genotypes, and genotypic diversity among PCB-degrading bacteria in toxic chemical-polluted soil environments. We suggest that the DNA probe should be used with caution for accurate assessment of PCB-degradative capacity within soils and further recommend that a combination of DNA probe and biodegradation assay be used to determine the abundance of PCB-degrading bacteria in the soil bacterial community.

  10. Photocatalytic degradation of pollutants from Elcogas IGCC power station effluents.

    PubMed

    Durán, A; Monteagudo, J M; San Martín, I; García-Peña, F; Coca, P

    2007-06-01

    The aim of this work is to improve the quality of water effluents coming from Elcogas IGCC power station (Puertollano, Spain) with the purpose of fulfilling future more demanding normative, using heterogeneous photocatalytic oxidation processes (UV/H(2)O(2)/TiO(2) or ZnO). The efficiency of photocatalytic degradation for the different catalysts (TiO(2) and ZnO) was determined from the analysis of the following parameters: cyanides, formates and ammonia content. In a first stage, the influence of two parameters (initial concentration of H(2)O(2) and amount of catalyst) on the degradation kinetics of cyanides and formates was studied based on a factorial experimental design. pH was always kept in a value >9.5 to avoid gaseous HCN formation. The degradation of cyanides and formates was found to follow pseudo-first order kinetics. Experimental kinetic constants were fitted using neural networks (NNs). The mathematical model reproduces experimental data within 90% of confidence and allows the simulation of the process for any value of parameters in the experimental range studied. Moreover, a measure of the saliency of the input variables was made based upon the connection weights of the neural networks, allowing the analysis of the relative relevance of each variable with respect to the others. Results showed that the photocatalytic process was effective, being the degradation rate of cyanides about five times higher when compared to removal of formates. Finally, the effect of lowering pH on the degradation of formates was evaluated after complete cyanides destruction was reached (10 min of reaction). Under the optimum conditions (pH 5.2, [H(2)O(2)]=40 g/l; [TiO(2)]=2g/l), 100% of cyanides and 92% of initial NH(3) concentration are degraded after 10 min, whereas 35 min are needed to degrade 98% of formates.

  11. The abiotic degradation of soil organic matter to oxalic acid

    NASA Astrophysics Data System (ADS)

    Studenroth, Sabine; Huber, Stefan; Schöler, H. F.

    2010-05-01

    The abiotic degradation of soil organic matter to volatile organic compounds was studied intensely over the last years (Keppler et al., 2000; Huber et al., 2009). It was shown that soil organic matter is oxidised due to the presence of iron (III), hydrogen peroxide and chloride and thereby produces diverse alkyl halides, which are emitted into the atmosphere. The formation of polar halogenated compounds like chlorinated acetic acids which are relevant toxic environmental substances was also found in soils and sediments (Kilian et al., 2002). The investigation of the formation of other polar halogenated and non-halogenated compounds like diverse mono- and dicarboxylic acids is going to attain more and more importance. Due to its high acidity oxalic acid might have impacts on the environment e.g., nutrient leaching, plant diseases and negative influence on microbial growth. In this study, the abiotic formation of oxalic acid in soil is examined. For a better understanding of natural degradation processes mechanistic studies were conducted using the model compound catechol as representative for structural elements of the humic substances and its reaction with iron (III) and hydrogen peroxide. Iron is one of the most abundant elements on earth and hydrogen peroxide is produced by bacteria or through incomplete reduction of oxygen. To find suitable parameters for an optimal reaction and a qualitative and quantitative analysis method the following reaction parameters are varied: concentration of iron (III) and hydrogen peroxide, time dependence, pH-value and influence of chloride. Analysis of oxalic acid was performed employing an ion chromatograph equipped with a conductivity detector. The time dependent reaction shows a relatively fast formation of oxalic acid, the optimum yield is achieved after 60 minutes. Compared to the concentration of catechol an excess of hydrogen peroxide as well as a low concentration of iron (III) are required. In absence of chloride the

  12. Concentration-dependent kinetics of pollutant desorption from soils.

    PubMed

    Braida, Washington J; White, Jason C; Zhao, Dongye; Ferrandino, Francis J; Pignatello, Joseph J

    2002-12-01

    Sorption-desorption kinetics play a major role in transport and bioavailability of pollutants in soils. Contaminant concentration is a potentially important factor controlling kinetics. A previous paper dealt with the effect of solute concentration on fractional uptake rates of phenanthrene and pyrene from a finite aqueous source. In this study we determined the effect of initial phenanthrene sorbed concentration (q(0)) on the fractional mass desorption rates from each of six soils to a zero-concentration solution, approximated by including a polymer adsorbent (Tenax) as a third-phase sink. The soils were preequilibrated with phenanthrene for 180 d. Consistent with theory, the fractional desorption rates determined by empirical curve fitting increased with q(0) provided the isotherm was nonlinear. After 500 to 600 d of desorption at the steepest possible concentration gradient, all soils retained a highly resistant fraction, which ranged from 4 to 31% of q(0), except for one soil at a high q(0). The highly resistant fraction decreased with increasing q(0), for nonlinear isotherm cases, but increased with q(0) for linear or nearly linear isotherm cases. Application of a nonlinear diffusion model, the dual-mode diffusion model (DMDM), to the nonresistant fraction gave reasonably good fits. The DMDM attributes the increase with concentration of the apparent diffusivity to a decrease in the proportion of sorbate occupying immobile sites (holes) in soil organic matter. The concentration-dependent term in the expression for the apparent diffusivity correlated with either of two indices that reflect the linearity of the sorption isotherm. Bunker C oil present in one soil acted as a partition domain. The findings of this study are consistent with heterogeneous models of soil organic matter, and indicate that concentration effects should be taken into account whenever desorption rate is important.

  13. [Effects of multiple environmental factors on triflulsulfuron-methyl degradation in soils].

    PubMed

    Song, Ning-Hui; Shan, Zheng-Jun; Shi, Li-Li; Guo, Min; Xu, Jing; Kong, De-Yang

    2012-12-01

    Triflulsulfuron-methyl, a widely used sulfonylurea herbicide, has done harm to the soil and crop. Its environment fate was affected by many factors such as physicochemical or biological factors. In order to understand the effects of different environmental factors on the degradation of triflulsulfuron-methyl in soil, simulated indoor incubation experiments were carried out to explore the effects of soil microbe, soil type, dissolved organic matter (DOM), temperature, and soil moisture on triflulsulfuron-methyl degradation in soils. The results showed that different environmental factors such as temperature, soil moisture, soil microorganisms and soil type influenced triflulsulfuron-methyl degradation in different degrees. The increased soil microbial biomass, soil organic matters and DOM were beneficial to the soil degradation of triflulsulfuron-methyl, meanwhile, the decrease in soil pH could accelerate its degradation in soils. The results showed that soil microorganisms were the main factor effecting the degradation of triflulsulfuron-methyl in soil. Our results provided initial data for the conclusion that a set of biological and physiochemical factors coordinately regulate the decay of triflulsulfuron-methyl in soils.

  14. Detoxification mechanisms, defense responses, and toxicity threshold in the earthworm Eisenia foetida exposed to ciprofloxacin-polluted soils.

    PubMed

    Wang, Chengrun; Rong, Hong; Liu, Haitao; Wang, Xiaofei; Gao, Yixin; Deng, Ruhua; Liu, Ruiyu; Liu, Yun; Zhang, Di

    2017-08-29

    The widespread application of antibiotics poses health risks for agro-ecosystems. This study examined the effects of ciproflaxin (CIP)-polluted soils (0-51.2mgCIP/kg) on the earthworm Eisenia foetida. The enhanced activities and isozyme levels of superoxide dismutase (SOD) and ascorbate peroxidase after 15days of CIP exposure suggested reactive oxygen species overproduction and thus the generation of oxidatively damaged proteins (e.g., carbonylated proteins) in the earthworms. Under mild CIP stress, the 20S proteasome was capable of degrading most of the damaged proteins independent of ubiquitin. Under severe stress, proteases and endoproteases were up-regulated and maintained the proteolysis as 20S proteasome activity diminished. These observations suggested that, together with glutathione S-transferases, which also participated in the detoxification, 20S proteasome, proteases, endoproteases, and antioxidant enzymes constituted a detoxification and defense system in the earthworms. The biphasic dose responses of these cellular components confirmed that the dose range tested was reasonable for the bioassay of CIP-polluted soils. Our results also demonstrated the potential utility of SOD and ubiquitin as highly sensitive biomarkers in the early bioassay of CIP-polluted soils. Bases on the results, a toxicity threshold for CIP-polluted soils of 3.2-6.4mgCIP/kg soil can be proposed. Copyright © 2017. Published by Elsevier B.V.

  15. Selective photocatalytic degradation of aquatic pollutants by titania encapsulated into FAU-type zeolites.

    PubMed

    Zhang, Guan; Choi, Wonyong; Kim, Seok Han; Hong, Suk Bong

    2011-04-15

    The selective photocatalytic degradation of charged pollutants in water was achieved on titania encapsulated into FAU-type zeolites. The electrostatic attraction of cationic substrates and repulsion of anionic substrates by the negatively charged zeolite framework facilitated the selective photocatalytic degradation of charged substrates. The hybrid zeolite-titania photocatalysts were prepared through the ion-exchange method. The titania clusters were mainly well distributed within the cavities of FAU-type zeolites whereas no TiO(2) nanoparticles aggregates were observed on the external surface of zeolite crystals. The hybrid zeolite-titania photocatalysts were characterized by diffuse reflectance UV-visible spectroscopy, transmission electron microscopy, energy-dispersive X-ray analysis and X-ray photoelectron spectroscopy. The selective degradation of charged pollutants was investigated by employing three pairs of oppositely charged substrates. The comparison between the cationic and anionic substrates clearly showed that the degradation rates for the cationic substrates on the hybrid photocatalysts are markedly higher than those for the anionic substrates. Among the cationic substrates, the smaller cations such as tetramethylammoniums were preferentially degraded. This enabled the selective removal of cationic substrates among the mixture. Such a selective photocatalytic degradation of water pollutants may provide a useful strategy for the development of economical photocatalytic process by targeting only the most recalcitrant pollutant. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Biological degradation and microbial function effect of norfloxacin in a soil under different conditions.

    PubMed

    Yang, Ji-Feng; Ying, Guang-Guo; Liu, Shan; Zhou, Li-Jun; Zhao, Jian-Liang; Tao, Ran; Peng, Ping-An

    2012-01-01

    This paper investigated the degradation kinetics of norfloxacin in a soil, and its effects on soil respiration and nitrogen transformation under different conditions. Compared to the sterile control, the degradation rates of norfloxacin in the non-sterile soil were greatly enhanced, suggesting that microorganisms played a major role in the degradation. Accelerated degradation for norfloxacin in the soil was observed with decreasing concentrations (30 mg/kg to 5 mg/kg) with its half-life decreasing from 62 days to 31 days. Amending swine manure into the soil and increasing the soil moisture level enhanced the biological degradation of norfloxacin. No obvious inhibition of norfloxacin on soil respiration was observed in the soil, while only slight effect on nitrogen transformation was found. The results suggested that norfloxacin at the reported environmental concentrations (<100 mg/kg) would have little effect on microbial activity and functions in the soils.

  17. Soil microbial communities as suitable bioindicators of trace metal pollution in agricultural volcanic soils

    NASA Astrophysics Data System (ADS)

    Parelho, Carolina; dos Santos Rodrigues, Armindo; do Carmo Barreto, Maria; Gonçalo Ferreira, Nuno; Garcia, Patrícia

    2015-04-01

    Summary: The biological, chemical and physical properties of soil confer unique characteristics that enhance or influence its overall biodiversity. The adaptive character of soil microbial communities (SMCs) to metal pollution allows discriminating soil health, since changes in microbial populations and activities may function as excellent indicators of soil pollutants. Volcanic soils are unique naturally fertile resources, extensively used for agricultural purposes and with particular physicochemical properties that may result in accumulation of toxic substances, such as trace metals (TM). In our previous works, we identified priority TM affecting agricultural Andosols under different agricultural land uses. Within this particular context, the objectives of this study were to (i) assess the effect of soil TM pollution in different agricultural systems (conventional, traditional and organic) on the following soil properties: microbial biomass carbon, basal soil respiration, metabolic quotient, enzymatic activities (β-glucosidase, acid phosphatase and dehydrogenase) and RNA to DNA ratio; and (ii) evaluate the impact of TM in the soil ecosystem using the integrated biomarker response (IBR) based on a set of biochemical responses of SMCs. This multi-biomarker approach will support the development of the "Trace Metal Footprint" for different agricultural land uses in volcanic soils. Methods: The study was conducted in S. Miguel Island (Azores, Portugal). Microbial biomass carbon was measured by chloroform-fumigation-incubation-assay (Vance et al., 1987). Basal respiration was determined by the Jenkinson & Powlson (1976) technique. Metabolic quotient was calculated as the ratio of basal respiration to microbial biomass C (Sparkling & West, 1988). The enzymatic activities of β-glucosidase and acid phosphatase were determined by the Dick et al. (1996) method and dehydrogenase activity by the Rossel et al. (1997) method. The RNA and DNA were co-extracted from the same

  18. Tracing source pollution in soils using cadmium and lead isotopes.

    PubMed

    Cloquet, C; Carignan, J; Libourel, G; Sterckeman, T; Perdrix, E

    2006-04-15

    Tracing the source of heavy metals in the environment is of key importance for our understanding of their pollution and natural cycles in the surface Earth reservoirs. Up to now, most exclusively Pb isotopes were used to effectively trace metal pollution sources in the environment. Here we report systematic variations of Cd isotope ratios measured in polluted topsoils surrounding a Pb-Zn refinery plant in northern France. Fractionated Cd was measured in soil samples surrounding the refinery, and this fractionation can be attributed to the refining processes. Despite the Cd isotopic ratios being precisely measured, the obtained uncertainties are still large compared to the total isotopic variation. Nevertheless, for the first time, Cd isotopically fractionated by industrial processes may be traced in the environment. On the same samples, Pb isotope systematics suggested that materials actually used by the refinery were not the major source of Pb in soils, probably because refined ore origins changed over the 100 years of operation. On the other hand, Cd isotopes and concentrations measured in topsoils allowed identification of three main origins (industrial dust and slag and agriculture), assuming that all Cd ores are not fractionated, as suggested by terrestrial rocks so far analyzed, and calculation of their relative contributions for each sampling point. Understanding that this refinery context was an ideal situation for such a study, our results lead to the possibility of tracing sources of anthropogenic Cd and better constrain mixing processes, fluxes, transport, and phasing out of industrial input in nature.

  19. The toxicity and fate of phenolic pollutants in the contaminated soils associated with the oil-shale industry.

    PubMed

    Kahru, Anne; Maloverjan, Alla; Sillak, Helgi; Põllumaa, Lee

    2002-01-01

    Phenol, cresols, dimethylphenols and resorcinols considered major pollutants in the oil-shale semi-coke dump leachates (up to 380 mg phenols/L) that contaminate the surrounding soils and pose a threat to the groundwater in the North-East of Estonia. However; despite high residual concentrations of polyaromatic hydrocarbons (PAHs) and oil products in these soils, the concentration of phenols (especially their water-extractable fraction) was low, not exceeding 0.7 mg/kg dwt. The aim of the current study was to evaluate the role of biodegradation and aging on the decrease of hazard caused by phenolic pollution. The extractability of phenols (phenol, cresols, dimethylphenols and resorcinols) and their biodegradability by the microbial population was studied in the 13 soils sampled from the Estonian oil-shale region, territories of former gas stations, and from presumably non-polluted areas. Phenol, 5-methylresorcinol, p-cresol and resorcinol could be considered easily degradable in the soils as the microbial populations from majority of the soils studied were able to grow on mineral medium supplemented with these phenols as a single source of carbon. 2,3- and 2,4- and 3,4-dimethylphenols could be considered less easily biodegradable. The semi-coke dump leachate polluted soil (containing no dibasic phenols, 43 mg of monobasic phenols, 1348 mg of oil products and 35 mg of PAHs per g dwt) was analyzed chemically (HPLC) and toxicologically (Flash-Assay using Vibrio fischeri) for the leaching of phenols during shaking of soil-water slurries for 24 h. Only 5.8% of the total concentration of phenols was water-extractable, whereas about 50% of the leached amount was biodegraded by the soil microorganisms. Phenol and cresols were biodegraded by 80%, but the concentration of dimethylphenols practically did not change. The pollutants (measured as total water-extractable toxicity) were desorbed from the soil particles by the 8th h of extraction, whereas the toxicity of the aqueous

  20. Reclamation of DPK hydrocarbon polluted agricultural soil using a selected bulking agent.

    PubMed

    Nwankwegu, Amechi S; Onwosi, Chukwudi O; Orji, Michael U; Anaukwu, Chika G; Okafor, Uchenna C; Azi, Fidelis; Martins, Paul E

    2016-05-01

    In the present study, laboratory scale bioremediation of dual purpose kerosene (DPK) hydrocarbon polluted soil using bulking agent (saw dust) was carried out. The effect of different parameters such as total petroleum hydrocarbon (TPH), dehydrogenase activity (DHase) and pH on bioremediation performance were evaluated. Studied parameters such as microbial dynamics, percentage degradation (95.20%), DHase (8.20 ± 0.43) were found to be higher in saw dust amended system and significantly differed with control at p < 0.05. Experimental data adequately fitted the first order kinetic thus, generated r(2) values (0.966), first order degradation constant (0.659 d(-1)), and degradation half-life t1/2 = ln2/k (1.05 d). Micrococcus luteus, Bacillus sp., Rhizopus arrhizus and Aspergillus sp. were isolated from the study. The use of saw dust as bulking agent greatly increased biodegradation rate and resulted in effective DPK hydrocarbon clean up. Therefore, saw dust could serve as an effective biostimulant towards improved bioremediation of hydrocarbon polluted environment.

  1. Soil organic matter degradation and enzymatic profiles of intertidal and subaqueous soils

    NASA Astrophysics Data System (ADS)

    Ferronato, Chiara; Marinari, Sara; Bello, Diana; Vianello, Gilmo; Trasar-Cepeda, Carmen; Vittori Antisari, Livia

    2017-04-01

    The interest on intertidal and subaqueous soils has recently arisen because of the climate changes forecasts. The preservation of these habitats represents an important challenge for the future of humanity, because these systems represent an important global C sink since soil organic matter (SOM) on intertidal and subaqueous soils undergoes very slow degradation rates due to oxygen limitation. Publications on SOM cycle in saltmarshes are very scarce because of the difficulties involved on those studies i.e. the interaction of many abiotic and biotic factors (e.g., redox changes, water and bio-turbation processes, etc) and stressors (e.g., salinity and anoxia). However, saltmarshes constitute an unique natural system to observe the influence of anoxic conditions on SOM degradation, because the tide fluctuations on the soil surface allow the formation of provisionally or permanently submerged soils. With the aim to investigate the quality of SOM in subaqueous soils, triplicates of subaqueous soils (SASs), intertidal soils (ITSs) and terrestrial soils (TESs) were collected in the saltmarshes of the Baiona Lagoon (Northern Italy) and classified according to their pedogenetic horizons. The SOM quality on each soil horizon was investigated by quantifying SOM, total and water-soluble organic carbon (TOC, WSC) and microbial biomass carbon (MBC). Given the contribution of soil enzymes to the degradation of SOM, some enzymatic assays were also performed. Thereafter, soil classification and humus morpho-functional classification were used to join together similar soil profiles to facilitate the description and discussion of results. Soils were ranked as Aquent or Wassent Entisols, with an A/AC/C pedosequence. SOM, TOC and MBC were statistically higher in A than in AC and C horizons. Among the A horizons, ITSs were those showing the highest values for these parameters (11% TOC, 1.6 mg kg-1 MBC, 0.9 mg kg-1 WSC). These results, combined with the morpho-functional classification

  2. Responses of butachlor degradation and microbial properties in a riparian soil to the cultivation of three different plants.

    PubMed

    Yang, Changming; Wang, Mengmeng; Chen, Haiyan; Li, Jianhua

    2011-01-01

    A pot experiment was conducted to investigate the biodegradation dynamics and related microbial ecophysiological responses to butachlor addition in a riparian soil planted with different plants such as Phragmites australis, Zizania aquatica, and Acorus calamus. The results showed that there were significant differences in microbial degradation dynamics of butachlor in the rhizosphere soils among the three riparian plants. A. calamus displays a significantly higher degradation efficiency of butachlor in the rhizosphere soils, as compared with Z. aquatica and P. australis. Half-life time of butachlor degradation in the rhizospheric soils of P. australis, Z. aquatica, and A. calamus were 7.5, 9.8 and 5.4 days, respectively. Residual butachlor concentration in A. calamus rhizosphere soil was 35.2% and 21.7% lower than that in Z. aquatica and P. australis rhizosphere soils, respectively, indicating that A. calamus showed a greater improvement effect on biodegradation of butachlor in rhizosphere soils than the other two riparian plant. In general, microbial biomass and biochemical activities in rhizosphere soils were depressed by butachlor addition, despite the riparian plant types. However, rhizospheric soil microbial ecophysiological responses to butachlor addition significantly (P < 0.05) differed between riparian plant species. Compared to Z. aquatica and P. australis, A. calamus showed significantly larger microbial number, higher enzyme activities and soil respiration rates in the rhizosphere soils. The results indicated that A. calamus have a better alleviative effect on inhibition of microbial growth due to butachlor addition and can be used as a suitable riparian plant for detoxifying and remediating butachlor contamination from agricultural nonpoint pollution.

  3. The interactions of composting and biochar and their implications for soil amendment and pollution remediation: a review.

    PubMed

    Wu, Haipeng; Lai, Cui; Zeng, Guangming; Liang, Jie; Chen, Jin; Xu, Jijun; Dai, Juan; Li, Xiaodong; Liu, Junfeng; Chen, Ming; Lu, Lunhui; Hu, Liang; Wan, Jia

    2016-10-17

    Compost and biochar, used for the remediation of soil, are seen as attractive waste management options for the increasing volume of organic wastes being produced. This paper reviews the interaction of biochar and composting and its implication for soil amendment and pollution remediation. The interaction of biochar and composting affect each other's properties. Biochar could change the physico-chemical properties, microorganisms, degradation, humification and gas emission of composting, such as the increase of nutrients, cation exchange capacity (CEC), organic matter and microbial activities. The composting could also change the physico-chemical properties and facial functional groups of biochar, such as the improvement of nutrients, CEC, functional groups and organic matter. These changes would potentially improve the efficiency of the biochar and composting for soil amendment and pollution remediation. Based on the above review, this paper also discusses the future research required in this field.

  4. Response of soil microbial activity and biodiversity in soils polluted with different concentrations of cypermethrin insecticide.

    PubMed

    Tejada, Manuel; García, Carlos; Hernández, Teresa; Gómez, Isidoro

    2015-07-01

    We performed a laboratory study into the effect of cypermethrin insecticide applied to different concentrations on biological properties in two soils [Typic Xerofluvent (soil A) and Xerollic Calciorthid (soil B)]. Two kg of each soil were polluted with cypermethrin at a rate of 60, 300, 600, and 1,200 g ha(-1) (C1, C2, C3, and C4 treatments). A nonpolluted soil was used as a control (C0 treatment). For all treatments and each experimental soil, soil dehydrogenase, urease, β-glucosidase, phosphatase, and arylsulphatase activities and soil microbial community were analysed by phospholipid fatty acids, which were measured at six incubation times (3, 7, 15, 30, 60, and 90 days). The behavior of the enzymatic activities and microbial population were dependent on the dose of insecticide applied to the soil. Compared with the C0 treatment, in soil A, the maximum inhibition of the enzymatic activities was at 15, 30, 45, and 90 days for the C1, C2, C3, and C4 treatments, respectively. However, in soil B, the maximum inhibition occurred at 7, 15, 30, and 45 days for the C1, C2, C3, and C4 treatments, respectively. These results suggest that the cypermethrin insecticide caused a negative effect on soil enzymatic activities and microbial diversity. This negative impact was greater when a greater dose of insecticide was used; this impact was also greater in soil with lower organic matter content. For both soils, and from these respective days onward, the enzymatic activities and microbial populations progressively increased by the end of the experimental period. This is possibly due to the fact that the insecticide or its breakdown products and killed microbial cells, subsequently killed by the insecticide, are being used as a source of energy or as a carbon source for the surviving microorganisms for cell proliferation.

  5. Determination of degradation rates of organic substances in the unsaturated soil zone depending on the grain size fractions of various soil types

    NASA Astrophysics Data System (ADS)

    Fichtner, Thomas; Stefan, Catalin; Goersmeyer, Nora

    2015-04-01

    Rate and extent of the biological degradation of organic substances during transport through the unsaturated soil zone is decisively influenced by the chemical and physical properties of the pollutants such as water solubility, toxicity and molecular structure. Furthermore microbial degradation processes are also influenced by soil-specific properties. An important parameter is the soil grain size distribution on which the pore volume and the pore size depends. Changes lead to changes in air and water circulation as well as preferred flow paths. Transport capacity of water inclusive nutrients is lower in existing bad-drainable fine pores in soils with small grain size fractions than in well-drainable coarse pores in a soil with bigger grain size fractions. Because fine pores are saturated with water for a longer time than the coarse pores and oxygen diffusion in water is ten thousand times slower than in air, oxygen is replenished much slower in soils with small grain size fractions. As a result life and growth conditions of the microorganisms are negatively affected. This leads to less biological activity, restricted degradation/mineralization of pollutants or altered microbial processes. The aim of conducted laboratory column experiments was to study the correlation between the grain size fractions respectively pore sizes, the oxygen content and the biodegradation rate of infiltrated organic substances. Therefore two columns (active + sterile control) were filled with different grain size fractions (0,063-0,125 mm, 0,2-0,63 mm and 1-2 mm) of soils. The sterile soil was inoculated with a defined amount of a special bacteria culture (sphingobium yanoikuae). A solution with organic substances glucose, oxalic acid, sinaphylic alcohol and nutrients was infiltrated from the top in intervals. The degradation of organic substances was controlled by the measurement of dissolved organic carbon in the in- and outflow of the column. The control of different pore volumes

  6. Use of phytoremediation and biochar to remediate heavy metal polluted soils: a review

    NASA Astrophysics Data System (ADS)

    Paz-Ferreiro, J.; Lu, H.; Fu, S.; Méndez, A.; Gascó, G.

    2013-11-01

    Anthropogenic activities are resulting in an increase on the use and extraction of heavy metals. Heavy metals cannot be degraded and hence accumulate in the environment having the potential to contaminate the food chain. This pollution threatens soil quality, plant survival and human health. The remediation of heavy metals deserves attention, but it is impaired by the cost of these processes. Phytoremediation and biochar are two sound environmental technologies which could be at the forefront to mitigate soil pollution. This review provides an overview of the current state of knowledge phytoremediation and biochar application to remediate heavy metal contaminated soils, discussing the advantages and disadvantages of both individual approaches. Research to date has attempted only in a limited number of occasions to combine both techniques, however we discuss the potential advantages of combining both remediation techniques and the potential mechanisms involved in the interaction between phytoremediators and biochar. We identified specific research needs to ensure a sustainable use of phytoremediation and biochar as remediation tools.

  7. Evaluation of Ricinus communis L. for the Phytoremediation of Polluted Soil with Organochlorine Pesticides

    PubMed Central

    Rissato, Sandra Regina; Galhiane, Mário Sergio; Fernandes, João Roberto; Gomes, Homero Marques; Ribeiro, Renata; de Almeida, Marcos Vinícius

    2015-01-01

    Phytoremediation is an attractive alternative to conventional treatments of soil due to advantages such as low cost, large application areas, and the possibility of in situ treatment. This study presents the assessment of phytoremediation processes conducted under controlled experimental conditions to evaluate the ability of Ricinus communis L., tropical plant species, to promote the degradation of 15 persistent organic pollutants (POPs), in a 66-day period. The contaminants tested were hexachlorocyclohexane (HCH), DDT, heptachlor, aldrin, and others. Measurements made in rhizosphere soil indicate that the roots of the studied species reduce the concentration of pesticides. Results obtained during this study indicated that the higher the hydrophobicity of the organic compound and its molecular interaction with soil or root matrix the greater its tendency to concentrate in root tissues and the research showed the following trend: HCHs < diclofop-methyl < chlorpyrifos < methoxychlor < heptachlor epoxide < endrin < o,p′-DDE < heptachlor < dieldrin < aldrin < o,p′-DDT < p,p′-DDT by increasing order of log K ow values. The experimental results confirm the importance of vegetation in removing pollutants, obtaining remediation from 25% to 70%, and demonstrated that Ricinus communis L. can be used for the phytoremediation of such compounds. PMID:26301249

  8. Evaluation of Ricinus communis L. for the Phytoremediation of Polluted Soil with Organochlorine Pesticides.

    PubMed

    Rissato, Sandra Regina; Galhiane, Mário Sergio; Fernandes, João Roberto; Gerenutti, Marli; Gomes, Homero Marques; Ribeiro, Renata; de Almeida, Marcos Vinícius

    2015-01-01

    Phytoremediation is an attractive alternative to conventional treatments of soil due to advantages such as low cost, large application areas, and the possibility of in situ treatment. This study presents the assessment of phytoremediation processes conducted under controlled experimental conditions to evaluate the ability of Ricinus communis L., tropical plant species, to promote the degradation of 15 persistent organic pollutants (POPs), in a 66-day period. The contaminants tested were hexachlorocyclohexane (HCH), DDT, heptachlor, aldrin, and others. Measurements made in rhizosphere soil indicate that the roots of the studied species reduce the concentration of pesticides. Results obtained during this study indicated that the higher the hydrophobicity of the organic compound and its molecular interaction with soil or root matrix the greater its tendency to concentrate in root tissues and the research showed the following trend: HCHs < diclofop-methyl < chlorpyrifos < methoxychlor < heptachlor epoxide < endrin < o,p'-DDE < heptachlor < dieldrin < aldrin < o,p'-DDT < p,p'-DDT by increasing order of log K ow values. The experimental results confirm the importance of vegetation in removing pollutants, obtaining remediation from 25% to 70%, and demonstrated that Ricinus communis L. can be used for the phytoremediation of such compounds.

  9. Extreme pollution of soils by emissions of the copper-nickel industrial complex in the Kola Peninsula

    NASA Astrophysics Data System (ADS)

    Kashulina, G. M.

    2017-07-01

    The distribution of the total Ni, Cu, Co, Cd, Pb, and Zn contents was studied in the soil profiles of six catenas in the zone subjected to emissions of the copper-nickel industrial complex, which is the largest source of SO2 and heavy metals in northern Europe. The results show that, at present, the concentrations of Ni and Cu in the upper organic soil horizons in the impact zone reach extreme levels of 9000 and 6000 mg/kg, respectively. Under conditions of the long-term intense multi-element industrial emissions, the modern levels of the accumulation of polluting substances in soils greatly depend on the indirect factors, such as the degree of the technogenic degradation of soils with the loss of a significant part of soil organic matter, the reaching of threshold saturation of the topsoil with polluting metals, and competitive relationships between chemical elements. The state of the ecosystems in the impact zone varied greatly and did not always agree with the contents of the main metals-pollutants in the soils. The moisture conditions determined by the landscape position affected significantly the resistance of the ecosystems to emissions.

  10. Stabilization of microbial biomass in soils: Implications for SOM formation and xenobiotics degradation

    NASA Astrophysics Data System (ADS)

    Miltner, A.; Kindler, R.; Achtenhagen, J.; Nowak, K.; Girardi, C.; Kästner, M.

    2012-04-01

    specific molecular architecture controls carbon mineralization and balance. The process is also involved in the fate of environmental contaminants in soil. This has been demonstrated by studies on the biodegradation of isotope labeled 2,4-D, MCPA and ibuprofen in soil where we quantified the contribution of microbial biomass residues to nonextractable residues (NER) in soil. The high amount of label found in biomolecules (fatty acids, amino acids) indicated that virtually all of the NER was made up by microbial biomass residues. We therefore conclude that stabilization of cell wall residues plays an important role in both SOM formation and pollutant degradation in soil.

  11. The chiral herbicide beflubutamid (II): Enantioselective degradation and enantiomerization in soil, and formation/degradation of chiral metabolites.

    PubMed

    Buerge, Ignaz J; Müller, Markus D; Poiger, Thomas

    2013-07-02

    Beflubutamid is a chiral soil herbicide currently marketed as racemate against dicotyledonous weeds in cereals. Biotests have shown that (-)-beflubutamid is at least 1000× more active than (+)-beflubutamid. Potential substitution of the racemate by (-)-beflubutamid should therefore be further considered. Here, we investigated the degradation behavior in soils and formation and degradation of two chiral metabolites. Laboratory incubation experiments were performed with an alkaline and an acidic soil. The compounds were analyzed by enantioselective GC-MS. Degradation rate constants were determined by kinetic modeling. In the alkaline soil, degradation of beflubutamid was slightly enantioselective, with slower degradation of the herbicidally active (-)-enantiomer. In the acidic soil, however, both enantiomers were degraded at similar rates. In contrast, degradation of a phenoxybutanamide metabolite was highly enantioselective. Chiral stability of beflubutamid and its metabolites was studied in separate incubations with the pure enantiomers in the same soils. In these experiments, (-)-beflubutamid was not converted to the nonactive (+)-enantiomer and vice versa. Significant enantiomerization was, however, observed for the major metabolite, a phenoxybutanoic acid. With regard to biological activity and behavior in soils, enantiopure (-)-beflubutamid definitively has the potential to substitute for the racemic herbicide.

  12. Effect of elevated CO2 on chlorpyriphos degradation and soil microbial activities in tropical rice soil.

    PubMed

    Adak, Totan; Munda, Sushmita; Kumar, Upendra; Berliner, J; Pokhare, Somnath S; Jambhulkar, N N; Jena, M

    2016-02-01

    Impact of elevated CO2 on chlorpyriphos degradation, microbial biomass carbon, and enzymatic activities in rice soil was investigated. Rice (variety Naveen, Indica type) was grown under four conditions, namely, chambered control, elevated CO2 (550 ppm), elevated CO2 (700 ppm) in open-top chambers and open field. Chlorpyriphos was sprayed at 500 g a.i. ha(-1) at maximum tillering stage. Chlorpyriphos degraded rapidly from rice soils, and 88.4% of initially applied chlorpyriphos was lost from the rice soil maintained under elevated CO2 (700 ppm) by day 5 of spray, whereas the loss was 80.7% from open field rice soil. Half-life values of chlorpyriphos under different conditions ranged from 2.4 to 1.7 days with minimum half-life recorded with two elevated CO2 treatments. Increased CO2 concentration led to increase in temperature (1.2 to 1.8 °C) that played a critical role in chlorpyriphos persistence. Microbial biomass carbon and soil enzymatic activities specifically, dehydrogenase, fluorescien diacetate hydrolase, urease, acid phosphatase, and alkaline phosphatase responded positively to elevated CO2 concentrations. Generally, the enzyme activities were highly correlated with each other. Irrespective of the level of CO2, short-term negative influence of chlorpyriphos was observed on soil enzymes till day 7 of spray. Knowledge obtained from this study highlights that the elevated CO2 may negatively influence persistence of pesticide but will have positive effects on soil enzyme activities.

  13. Methyl tert-butyl ether biodegradation by microbial consortia obtained from soil samples of gasoline-polluted sites in Mexico.

    PubMed

    Morales, Marcia; Velázquez, Elia; Jan, Janet; Revah, Sergio; González, Uriel; Razo-Flores, Elías

    2004-02-01

    Microbial consortia obtained from soil samples of gasoline-polluted sites were individually enriched with pentane, hexane, isooctane and toluene. Cometabolism with methyl tert-butyl ether, (MTBE), gave maximum degradation rates of 49, 12, 32 and 0 mg g(-1)protein h(-1), respectively. MTBE was fully degraded even when pentane was completely depleted with a cometabolic coefficient of 1 mgMTBE mg(-1)pentane. The analysis of 16S rDNA from isolated microorganisms in the pentane-adapted consortia showed that microorganisms could be assigned to Pseudomonas. This is the first work reporting the cometabolic mineralization of MTBE by consortium of this genus.

  14. Soil residue analysis and degradation of saflufenacil as affected by moisture content and soil characteristics

    USDA-ARS?s Scientific Manuscript database

    The objective of this study was to evaluate saflufenacil degradation and persistence in soils from rice regions under field capacity (non-flooded) and saturated (flooded) conditions. Saflufenacil dissolved in acetonitrile was added into pre-incubated samples at the rate of 2000 g ha-1. The amount of...

  15. Spontaneous plant colonization of brownfield soil and sludges and effects on substrate properties and pollutants mobility

    NASA Astrophysics Data System (ADS)

    Rocco, Claudia; Agrelli, Diana; Gonzalez, Maria Isabel; Mingo, Antonio; Motti, Riccardo; Stinca, Adriano; Coppola, Ida; Adamo, Paola

    2017-04-01

    This work was done on brownfield soil and sludges from a dismantled steel plant, moderately polluted by heavy metals (mainly Pb and Zn), 1) to analyzed the effects of substrate properties and environmental conditions on spontaneous vegetation; 2) to assess changes in the chemical properties of soils and sludges, with particular reference to the mobility and bioavailability of pollutants, induced by spontaneous plants revegetation. From 2006 to 2011, spontaneous plant colonization was monitored in the presence or absence of acidic peat both inside the degraded brownfield site and after transferal into a nearby Oak Park environment. During the five experimental years the vegetation growth was monitored using phytosociological method and data analyzed statistically. Both substrates, before and after plant growth, were analyzed for main chemical properties. Metals mobility and bioavailability was assessed using single (H2O; DTPA) and sequential extractions (EU-BCR). At the end of the experiment, plant ability to uptake metal was evaluated on selected species. Overall, 57 plant species grew healthily on the substrates. The combination of soil and sludges with peat resulted in an effective revegetation with a sensible increasing of plants biomass. Most of the species were found in the park (91%), showing plant colonization was mainly affected by the immediate environment rather than by substrate properties. Furthermore, after the five years, the substrate properties (pH, O.C.) were slightly affected by plant growth and, although metal pollutants in both substrates are characterized by low water solubility and DTPA availability, after plants growth an increase (even if not significant) of rhizospheric Cu, Fe, Mn and Zn solubility in H2O was detected. Metals speciation indicated a low risk of Pb and Zn mobility being either largely trapped in the mineralogical structure of oxides and silicates and occluded in easily reducible manganese or iron oxides. Restricted metal

  16. Chlorpyrifos degradation in soils with different treatment regimes within Nzoia River Drainage Basin, Kenya.

    PubMed

    Mutua, Gershom Kyalo; Ngigi, Anastasiah Njoki; Getenga, Zachary Moranga

    2015-03-01

    Two organic amendments, filter mud compost and Tithonia diversifolia leaves generated within a sugarcane growing area were used to enhance the degradation of chlorpyrifos in soil. Filter mud compost and T. diversifolia leaves significantly enhanced degradation of chlorpyrifos in soils (p < 0.05) with DT50 values of 21 and 24 days, respectively. Furthermore, field degradation of chlorpyrifos in soil with prior exposure to chlorpyrifos was significantly enhanced (p = 0.034) with DT50 of 21 days compared to 30 days in soil with no previous exposure. Degradation of chlorpyrifos in sterile and non-sterile soils were significantly different (p = 0.023) with DT50 values of 161 and 27 days, respectively. Results show enhanced degradation of chlorpyrifos in organically amended soils and soils with prior exposure to the pesticide. These amendments show promise in a continuing effort to reduce chlorpyrifos concentrations in soils.

  17. Approaches to the Assessment of the Efficiency of Remediation of Oil-Polluted Soils

    NASA Astrophysics Data System (ADS)

    Anchugova, E. M.; Melekhina, E. N.; Markarova, M. Yu.; Shchemelinina, T. N.

    2016-02-01

    Indices characterizing the enzymatic activity of soils and the contents of aliphatic and polycyclic aromatic hydrocarbons have been applied for estimating the efficiency of remediation of oil-polluted soils in the north of European Russia. Oil-polluted test plots treated with the Universal and Roder biopreparations and subjected to the agrochemical reclamation have been examined. The suggested indices can be used to diagnose and monitor the oil-polluted soils and to assess the efficiency of their remediation.

  18. Degradation of environment pollutant dyes using phytosynthesized metal nanocatalysts

    NASA Astrophysics Data System (ADS)

    MeenaKumari, M.; Philip, Daizy

    2015-01-01

    We present for the first time biogenic reduction and stabilization of gold and silver ions at room temperature using fruit juice of Punica granatum. The formation, morphology and crystalline structure of the synthesized nanoparticles are determined using UV-Visible, XRD and TEM. An attempt to reveal the partial role of phenolic hydroxyls in the reduction of Au3+ and Ag+ is done through FTIR analysis. The synthesized nanoparticles are used as potential catalysts in the degradation of a cationic phenothiazine dye, an anionic mono azo dye and a cationic fluorescent dye. The calculated values of percentage removal of dyes and the rate constants from pseudo first order kinetic data fit give a comparative study on degradation of organic dyes in presence of prepared gold and silver nanoparticles.

  19. Efficient degradation of organic pollutants in aqueous solution with bicarbonate-activated hydrogen peroxide.

    PubMed

    Xu, Aihua; Li, Xiaoxia; Xiong, Hui; Yin, Guochuan

    2011-02-01

    Bicarbonate anion is an efficient activator for hydrogen peroxide to generate many active oxygen species including peroxymonocarbonate (HCO(4)(-)), superoxide ion (O(2)(-)) and singlet oxygen ((1)O(2)). This study aims to understand the oxidative degradation of organic pollutants including methyl blue, methyl orange, rhodamine B, and 4-chlorophenol, with H(2)O(2) activated by sodium bicarbonate at room temperature. The obtained results indicate that such a method is apparently efficient in versatile pollutant degradation. Compared with using H(2)O(2) alone under similar pH conditions, the degradation rates of the pollutants were greatly enhanced through adding NaHCO(3). Through LC-MS, FT-IR and the TOC analysis, the degradation of methylene blue was revealed to proceed by the transformation of dimethylamino group in methylene blue to methylamino, aldehyde and nitro group, and the opening of phenyl ring into small molecular compounds and CO(2). The studies using the (1)O(2) scavenger sodium azide and the O(2)(-) indicator nitro blue tetrazolium suggest that the active O(2)(-) intermediate, generated from HCO(4)(-) decomposition, rather than (1)O(2) was involved in the pollutant degradation.

  20. Air pollution: Household soiling and consumer welfare losses

    USGS Publications Warehouse

    Watson, W.D.; Jaksch, J.A.

    1982-01-01

    This paper uses demand and supply functions for cleanliness to estimate household benefits from reduced particulate matter soiling. A demand curve for household cleanliness is estimated, based upon the assumption that households prefer more cleanliness to less. Empirical coefficients, related to particulate pollution levels, for shifting the cleanliness supply curve, are taken from available studies. Consumer welfare gains, aggregated across 123 SMSAs, from achieving the Federal primary particulate standard, are estimated to range from $0.9 to $3.2 million per year (1971 dollars). ?? 1982.

  1. Microbial Hydrocarbon and ToxicPollutant Degradation Method

    SciTech Connect

    Schlueter, Dietrich; Janabi, Mustafa; O'Neil, James; Budinger, Thomas

    2011-08-16

    The goal of this project is to determine optimum conditions for bacterial oxidation of hydrocarbons and long-chain alkanes that are representative of petroleum contamination of the environment. Polycyclic Aromatic Hydrocarbons (PAHs) are of concern because of their toxicity, low volatility, and resistance to microbial degradation, especially under anaerobic conditions. The uniqueness of our approach is to use carbon-11 in lieu of the traditional use of carbon-14.

  2. Contribution of increased mutagenesis to the evolution of pollutants-degrading indigenous bacteria

    PubMed Central

    Ilmjärv, Tanel; Naanuri, Eve; Kivisaar, Maia

    2017-01-01

    Bacteria can rapidly evolve mechanisms allowing them to use toxic environmental pollutants as a carbon source. In the current study we examined whether the survival and evolution of indigenous bacteria with the capacity to degrade organic pollutants could be connected with increased mutation frequency. The presence of constitutive and transient mutators was monitored among 53 pollutants-degrading indigenous bacterial strains. Only two strains expressed a moderate mutator phenotype and six were hypomutators, which implies that constitutively increased mutability has not been prevalent in the evolution of pollutants degrading bacteria. At the same time, a large proportion of the studied indigenous strains exhibited UV-irradiation-induced mutagenesis, indicating that these strains possess error-prone DNA polymerases which could elevate mutation frequency transiently under the conditions of DNA damage. A closer inspection of two Pseudomonas fluorescens strains PC20 and PC24 revealed that they harbour genes for ImuC (DnaE2) and more than one copy of genes for Pol V. Our results also revealed that availability of other nutrients in addition to aromatic pollutants in the growth environment of bacteria affects mutagenic effects of aromatic compounds. These results also implied that mutagenicity might be affected by a factor of how long bacteria have evolved to use a particular pollutant as a carbon source. PMID:28777807

  3. Soil erosion and degradation in Mediterranean Type Ecosystems. The Soil Erosion and Degradation Research Group (SEDER) approach and findings

    NASA Astrophysics Data System (ADS)

    Cerdà, Artemi; Keesstra, Saskia; Pulido, Manuel; Jordán, Antonio; Novara, Agata; Giménez-Morera, Antonio; Borja, Manuel Esteban Lucas; Francisco Martínez-Murillo, Juan; Rodrigo-Comino, Jesús; Pereira, Paulo; Nadal-Romero, Estela; Taguas, Tani; Úbeda, Xavier; Brevik, Eric C.; Tarolli, Paolo; Bagarello, Vicenzo; Parras Alcantara, Luis; Muñoz-Rojas, Miriam; Oliva, Marc; di Prima, Simone

    2017-04-01

    The Soil Erosion and Degradation Reseach Group (SEDER) is developing a research program since 2002 to assess the soil erosion and degradation processes at the Canyoles River watershed in Eastern Spain. The research study site was selected as representative of the environmental changes that take place in the Mediterranean: abandonment of the agriculture land in the mountains, forest fire expansion, intensification of the agriculture, impact of the infraesturctures such as rail and road embankments, and soil sealing due to the urban expansion. The research is based on the continuous measurements in the Montesa and El Teularet research stations and the sampling of the soils, topographical measurements and the use of rainfall simulators, minidisk infiltrometers, ring infiltrometers and Water Drop Penetration Time tests. The research is moving from a pure scientific approach to a more socio-economic view, and the stakeholders are being researched from a perception point of view. SEDER is also moving from pure to applied science, with the objective to design new managements that will satisfy the stakeholders and will achieve the sustainability. The research is being carried out in vineyards and orchards as they show extremely high erosion rates. But also we are interested in the impact of forest fires and the road embankments. In all three research topics, SEDER wish to find the sustainable managements. Acknowledgements The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 603498 (RECARE project) and the CGL2013- 47862-C2-1-R and CGL2016-75178-C2-2-R national research projects. References Bodí, M. B., Martin, D. A., Balfour, V. N., Santín, C., Doerr, S. H., Pereira, P., . . . Mataix-Solera, J. (2014). Corrigendum to "wildland fire ash: Production, composition and eco-hydro-geomorphic effects", earth sci. rev. 130 (2014) [103-127]. Earth-Science Reviews, 138, 503. doi:10

  4. Complete Genome Sequence of Polymorphum gilvum SL003B-26A1T, a Crude Oil-Degrading Bacterium from Oil-Polluted Saline Soil▿

    PubMed Central

    Li, Shu-Guang; Tang, Yue-Qin; Nie, Yong; Cai, Man; Wu, Xiao-Lei

    2011-01-01

    Polymorphum gilvum SL003B-26A1T is a type strain of a newly published novel species in the novel genus Polymorphum. It was isolated from a crude oil-polluted saline soil in Shengli Oilfield, China, and was able to use the crude oil as the sole carbon source. Here we report the complete genome of SL003B-26A1T and the genes likely to be involved in oil degradation and ecological adaption. PMID:21478361

  5. Bacterial degradation of naproxen--undisclosed pollutant in the environment.

    PubMed

    Wojcieszyńska, Danuta; Domaradzka, Dorota; Hupert-Kocurek, Katarzyna; Guzik, Urszula

    2014-12-01

    The presence of non-steroidal anti-inflammatory drugs (NSAIDs) in the environment is an emerging problem due to their potential influence on human health and biocenosis. This is the first report on the biotransformation of naproxen, a polycyclic NSAID, by a bacterial strain. Stenotrophomonas maltophilia KB2 transformed naproxen within 35 days with about 28% degradation efficiency. Under cometabolic conditions with glucose or phenol as a carbon source degradation efficiency was 78% and 40%, respectively. Moreover, in the presence of naproxen phenol monooxygenase, naphthalene dioxygenase, hydroxyquinol 1,2-dioxygenase and gentisate 1,2-dioxygenase were induced. This suggests that degradation of naproxen occurs by its hydroxylation to 5,7,8-trihydroxynaproxen, an intermediate that can be cleaved by hydroxyquinol 1,2-dioxygenase. The cleavage product is probably further oxidatively cleaved by gentisate 1,2-dioxygenase. The obtained results provide the basis for the use of cometabolic systems in the bioremediation of polycyclic NSAID-contaminated environments. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Assessment of potential soil degradation on agricultural land in the czech republic.

    PubMed

    Šarapatka, Bořivoj; Bednář, Marek

    2015-01-01

    Many attempts have been made worldwide to develop methods to identify the areas most threatened by soil degradation. Some soils in afflicted areas may be irreversibly degraded and thus have very little resilience (the ability to restore themselves). For the purpose of assessing the current state of soil degradation in the Czech Republic (CZ) we have developed an overall indicator of land vulnerability to the threat of soil degradation on the basis of individual factors that contribute to soil degradation and are monitored on a long-term basis in various research worksites in the CZ. Individual degradation factors were divided into two groups: chemical and physical degradation. On the basis of principal component analysis, individual degradation factors were assigned a specific weight of influence. With the use of a GIS, the input factors of degradation were combined to create maps of chemical and physical soil degradation, and consequently a map of overall degradation-threatened soils for the CZ, along with a map of areas differentiated according to the prevailing type of degradation. Results showed that, at present, the most important degradation factor in the CZ is water erosion, followed by loss of organic matter. Statistical analysis showed that approximately 51% of agricultural land is moderately threatened in the CZ.

  7. Soil quality degradation processes along a deforestation chronosequence in the Ziwuling Area, China

    USDA-ARS?s Scientific Manuscript database

    Accelerated erosion caused by deforestation and soil degradation has become the primary factor limiting sustainable utilization of soil resources on the Loess Plateau of Northwestern China. We studied the physical, chemical, and microbiological processes of soil degradation along a chronosequence o...

  8. Effects of 2,4-dichlorophenol, pentachlorophenol and vegetation on microbial characteristics in a heavy metal polluted soil.

    PubMed

    Lin, Qi; Zhao, Hong M; Chen, Ying X

    2007-01-01

    The aim of this study was to evaluate the soil microbial characteristics in historically heavy-metal polluted soil, which was also affected by organic co-contaminants, 2,4-dichlorophenol or pentachlorophenol, which often occur due to the conventional use of pesticides. It was observed that the normalized microbial biomass (microbial biomass per unit soil organic C) of the contaminated soil was very low, less than 1% in both non-planted and ryegrass planted soil, and showed a decreasing trend with the treatment of organic co-contaminants. The microbial biomass and substrate-induced respiration (SIR) in the ryegrass planted soil were much larger, as compared with the non-planted soil with or without organic pollutants. The different resistant bacterial community and its physiological diversity in the rhizosphere further suggested that the effect of vegetation on microbial activity was not just a general increase in the mass or activity of pre-existing microorganisms, but rather acted selectively on microbial growth so that the relative abundance of different microbial groups in soil was changed. In sum, high concentrations of organic co-contaminants, especially pentachlorophenol (PCP), could strengthen the deterioration of microbial ecology. The adverse effect of heavy metal-organic pollutants on the soil microbial biomass and activity might be the reason for the slow degradation of PCP that has high chlorinated and high toxicity. Vegetation might be the efficient way to assist in improving and restoring the utilization of agricultural ecosystems. The beneficial microbial effect of vegetation could cause the rapid dissipation of 2,4-dichlorophenol (2,4-DCP) that has less chlorinated and less toxicity in the planted soils.

  9. Effects of nano-sized zero-valent iron (nZVI) on DDT degradation in soil and its toxicity to collembola and ostracods.

    PubMed

    El-Temsah, Yehia S; Joner, Erik J

    2013-06-01

    Nano-sized zero valent iron (nZVI) has been studied for in situ remediation of contaminated soil and ground water. However, little is known about its effects on organisms in soil and aquatic ecosystems. In this study, the effect of nZVI on degradation of DDT and its ecotoxicological effects on collembola (Folsomia candida) and ostracods (Heterocypris incongruens) were investigated. Two soils were used in suspension incubation experiments lasting for 7 and 30 d; a spiked (20 mg DDT kg(-1)) sandy soil and an aged (>50 years) DDT-polluted soil (24 mg DDT kg(-1)). These were incubated with 1 or 10 g nZVI kg(-1), and residual toxicity in soil and the aqueous phase tested using ecotoxicological tests with collembola or ostracods. Generally, addition of either concentration of nZVI to soil led to about 50% degradation of DDT in spiked soil at the end of 7 and 30 d incubation, while the degradation of DDT was less in aged DDT-polluted soil (24%). Severe negative effects of nZVI were observed on both test organisms after 7 d incubation, but prolonged incubation led to oxidation of nZVI which reduced its toxic effects on the tested organisms. On the other hand, DDT had significant negative effects on collembolan reproduction and ostracod development. We conclude that 1 g nZVI kg(-1) was efficient for significant DDT degradation in spiked soil, while a higher concentration was necessary for treating aged pollutants in soil. The adverse effects of nZVI on tested organisms seem temporary and reduced after oxidation.

  10. Analysis of chlorothalonil and three degradates in sediment and soil

    USGS Publications Warehouse

    Hladik, M.L.; Kuivila, K.M.

    2008-01-01

    A method has been developed for the simultaneous extraction of chlorothalonil and three of its degradates (4-hydroxy-2,5,6- trichloroisophthalonitrile, 1-carbamoyl-3-cyano-4-hydroxy-2,5,6- trichlorobenzene, and 1,3-dicarbamoyl-2,4,5,6-tetrachlorobenzene) from soils and sediments; the compounds were extracted using sonication with acetone and isolation of the parent compound and matrix interferences from the degradates by solid phase extraction (SPE). The chlorothalonil fraction underwent further coextracted matrix interference removal with Florisil. The degradates were derivatized with N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) and chlorotrimethylsilane (TMCS). All compounds were analyzed by gas chromatography-mass spectrometry (GC-MS). Recoveries on a spiked (20 and 200 ??g kg-1) sediment ranged from 80% to 91% with calculated limits of detection of 1-5 ??g kg-1 dry weight sediment. An additional 20 sediment samples were collected in watersheds from the Southeastern United States where chlorothalonil is used widely on peanuts and other crops. None of the target compounds were detected. Laboratory fortified recoveries of chlorothalonil and its degradates in these environmental sediment samples ranged from 75% to 89%.

  11. Characteristics of current roadside pollution of soils in Upper Silesia

    NASA Astrophysics Data System (ADS)

    Wawer, M.; Szuszkiewicz, M.; Magiera, T.

    2012-04-01

    The aim of the study was qualitative recognition of contemporary roadside pollutants deposited on topsoils in areas located in close vicinity to roads with high traffic volume (main roads, ring roads). So far, the determination of pollutant content in soil samples has shown only the amount of pollutants deposited on soils over long time period, without the possibility to assess the quality changes in type of deposition and to determine the present structure of roadside pollution. Moreover, in many cases, it is difficult to distinguish roadside pollution from other industrial sources. In order to avoid this issue and recognize currently emergent threats of road traffic origin, three monitoring plots filled with quartz sand had been installed in Zabrze, Gliwice and Opole (Poland) close to arteries with high traffic volume. For installation of monitoring plots 7 cm of topsoil had been removed and replaced by boxes filled with clean quartz sand with known chemical composition and neutral magnetic properties (diamagnetic). This sand was treated as neutral matrix for the accumulation of traffic pollution. Results of chemical analyses of heavy metal contents and magnetic susceptibility measurements of removed topsoils have shown that the highest content of Fe, Mn, Zn, Pb, Cu, Cr and Ni were observed in Zabrze. Amount of Zn and Pb exceeded threshold values. Magnetic susceptibility values were also the highest in Zabrze. In all investigated areas magnetic susceptibility values and heavy metal contents decreased with the distance from the road. Measurements of sand from monitoring plots which were executed after 3, 6 and 12 months of exposure have shown that values of magnetic susceptibility have increased during these time periods. It is visible especially in surface layer of sand. Initially magnetic susceptibility value of quartz sand which was used as matrix after first year of exposure increased from 0,25 - 10-8 m3kg-1 to 300 in Zabrze, 50 in Gliwice and 30- 10-8 m3kg-1

  12. Monitoring Anaerobic TCE Degradation by Evanite Cultre in Column Packed with TCE-Contaminated Soil

    NASA Astrophysics Data System (ADS)

    Ko, J.; Han, K.; Ahn, G.; Park, S.; Kim, N.; Ahn, H.; Kim, Y.

    2011-12-01

    Trichloroethylene (TCE) is a long-term common groundwater pollutant because the compound with high density is slowly released into groundwater. Physical and chemical remediation processes have been used to clean-up the contaminant, but novel remediation technology is required to overcome a low efficiency of the traditional treatment process. Many researchers focused on biological process using an anaerobic TCE degrading culture, dehalococcoides spp., but it still needs to evaluate whether the process can be applied into field scale under aerobic condition. Therefore, in this work we examined two different types (i.e., Natural attenuation and bioaugmentation) of biological remediation process in anaerobic column packed with TCE-contaminated soil. A TCE degradation by indigenous microorganisms was confirmed by monitoring TCE and the metabolites (c-DCE, VC, ETH). However, TCE was transformed and stoichiometry amount of c-DCE was produced, and VC and ETH was not detected. To test bioaugmentation of Evanite culture containing dehalococcoides spp., Evanite culture was injected into the column and TCE degradation to c-DCE, VC, ETH was monitored. We are evaluating the transport of the Evanite culture in the column by measuring TCE and VC reductases. In the result, the TCE was completely degraded to ETH using hydrogen as electron donor generate by hydrogen-production fermentation from formate.

  13. Evidence of laser induced degradation and graphitization of aromatic pollutants

    NASA Astrophysics Data System (ADS)

    Mele, A.; Letardi, T.; di Lazarro, P.

    The laser-induced photodecomposition and graphitization of polynuclear aromatic hydrocarbons is investigated by irradiating solid pollutant samples with an Nd-YAG laser, leaving a carbon-rich, black powder. The irradiation of anthracene and benzopyrene forms the ions Cn(+)-, CnH(+)-, and CnH2(+)- in a wide plume produced by a pulsed-CO2 laser. The tendency of aromatic compounds to fragment is noted, and the notion that ion formation is governed by the mechanism that produces ablation in the laser cloud is suggested. Optical multichannel analyzer emission spectra indicate the production of the Cn species, suggesting applications to the treatment of aromatic product wastes.

  14. Can control of soil erosion mitigate water pollution by sediments?

    PubMed

    Rickson, R J

    2014-01-15

    The detrimental impact of sediment and associated pollutants on water quality is widely acknowledged, with many watercourses in the UK failing to meet the standard of 'good ecological status'. Catchment sediment budgets show that hill slope erosion processes can be significant sources of waterborne sediment, with rates of erosion likely to increase given predicted future weather patterns. However, linking on-site erosion rates with off-site impacts is complicated because of the limited data on soil erosion rates in the UK and the dynamic nature of the source-pathway-receptor continuum over space and time. Even so, soil erosion control measures are designed to reduce sediment production (source) and mobilisation/transport (pathway) on hill slopes, with consequent mitigation of pollution incidents in watercourses (receptors). The purpose of this paper is to review the scientific evidence of the effectiveness of erosion control measures used in the UK to reduce sediment loads of hill slope origin in watercourses. Although over 73 soil erosion mitigation measures have been identified from the literature, empirical data on erosion control effectiveness are limited. Baseline comparisons for the 18 measures where data do exist reveal erosion control effectiveness is highly variable over time and between study locations. Given the limitations of the evidence base in terms of geographical coverage and duration of monitoring, performance of the different measures cannot be extrapolated to other areas. This uncertainty in effectiveness has implications for implementing erosion/sediment risk reduction policies, where quantified targets are stipulated, as is the case in the EU Freshwater Fish and draft Soil Framework Directives. Also, demonstrating technical effectiveness of erosion control measures alone will not encourage uptake by land managers: quantifying the costs and benefits of adopting erosion mitigation is equally important, but these are uncertain and difficult to

  15. Engineering tobacco to remove mercury from polluted soil.

    PubMed

    Chang, S; Wei, F; Yang, Y; Wang, A; Jin, Z; Li, J; He, Y; Shu, H

    2015-04-01

    Tobacco is an ideal plant for modification to remove mercury from soil. Although several transgenic tobacco strains have been developed, they either release elemental mercury directly into the air or are only capable of accumulating small quantities of mercury. In this study, we constructed two transgenic tobacco lines: Ntk-7 (a tobacco plant transformed with merT-merP-merB1-merB2-ppk) and Ntp-36 (tobacco transformed with merT-merP-merB1-merB2-pcs1). The genes merT, merP, merB1, and merB2 were obtained from the well-known mercury-resistant bacterium Pseudomonas K-62. Ppk is a gene that encodes polyphosphate kinase, a key enzyme for synthesizing polyphosphate in Enterobacter aerogenes. Pcs1 is a tobacco gene that encodes phytochelatin synthase, which is the key enzyme for phytochelatin synthesis. The genes were linked with LP4/2A, a sequence that encodes a well-known linker peptide. The results demonstrate that all foreign genes can be abundantly expressed. The mercury resistance of Ntk-7 and Ntp-36 was much higher than that of the wild type whether tested with organic mercury or with mercuric ions. The transformed plants can accumulate significantly more mercury than the wild type, and Ntp-36 can accumulate more mercury from soil than Ntk-7. In mercury-polluted soil, the mercury content in Ntp-36's root can reach up to 251 μg/g. This is the first report to indicate that engineered tobacco can not only accumulate mercury from soil but also retain this mercury within the plant. Ntp-36 has good prospects for application in bioremediation for mercury pollution.

  16. Soil burial method for plastic degradation performed by Pseudomonas PL-01, Bacillus PL-01, and indigenous bacteria

    NASA Astrophysics Data System (ADS)

    Shovitri, Maya; Nafi'ah, Risyatun; Antika, Titi Rindi; Alami, Nur Hidayatul; Kuswytasari, N. D.; Zulaikha, Enny

    2017-06-01

    Lately, plastic bag is becoming the most important pollutant for environment since it is difficult to be naturally degraded due to it consists of long hydrocarbon polymer chains. Our previous study indicated that our pure isolate Pseudomonas PL-01 and Bacillus PL-01 could degrade about 10% plastic bag. This present study was aimed to find out whether Pseudomonas PL01 and Bacillus PL01 put a positive effect to indigenous bacteria from marginal area in doing plastic degradation with a soil burial method. Beach sand was used as a representative marginal area, and mangrove sediment was used as a comparison. Plastics were submerged into unsterile beach sand with 10% of Pseudomonas PL-01 or Bacillus PL-01 containing liquid minimal salt medium (MSM) separately, while other plastics were submerged into unsterile mangrove sediments. After 4, 8, 12 and 16 weeks, their biofilm formation on their plastic surfaces and plastic degradation were measured. Results indicated that those 2 isolates put positive influent on biofilm formation and plastic degradation for indigenous beach sand bacteria. Bacillus PL-01 put higher influent than Pseudomonas PL-01. Plastic transparent was preferable degraded than black and white plastic bag `kresek'. But anyhow, indigenous mangrove soil bacteria showed the best performance in biofilm formation and plastic degradation, even without Pseudomonas PL-01 or Bacillus PL-01 addition. Fourier Transform Infrared (FTIR) analysis complemented the results; there were attenuated peaks with decreasing peaks transmittances. This FTIR peaks indicated chemical functional group changes happened among the plastic compounds after 16 weeks incubation time.

  17. Saccharin and other artificial sweeteners in soils: estimated inputs from agriculture and households, degradation, and leaching to groundwater.

    PubMed

    Buerge, Ignaz J; Keller, Martina; Buser, Hans-Rudolf; Müller, Markus D; Poiger, Thomas

    2011-01-15

    Artificial sweeteners are consumed in substantial quantities as sugar substitutes and were previously shown to be ubiquitously present in the aquatic environment. The sweetener saccharin is also registered as additive in piglet feed. Saccharin fed to piglets was largely excreted and, consequently, found in liquid manure at concentrations up to 12 mg/L, where it was stable during 2 months of storage. Saccharin may thus end up in soils in considerable quantities with manure. Furthermore, other studies showed that saccharin is a soil metabolite of certain sulfonylurea herbicides. Sweeteners may also get into soils via irrigation with wastewater-polluted surface water, fertilization with sewage sludge (1-43 μg/L), or through leaky sewers. In soil incubation experiments, cyclamate, saccharin, acesulfame, and sucralose were degraded with half-lives of 0.4-6 d, 3-12 d, 3-49 d, and 8-124 d, respectively. The relative importance of entry pathways to soils was compared and degradation and leaching to groundwater were evaluated with computer simulations. The data suggest that detection of saccharin in groundwater (observed concentrations, up to 0.26 μg/L) is most likely due to application of manure. However, elevated concentrations of acesulfame in groundwater (up to 5 μg/L) may result primarily from infiltration of wastewater-polluted surface water through stream beds.

  18. Peach leaf responses to soil and cement dust pollution.

    PubMed

    Maletsika, Persefoni A; Nanos, George D; Stavroulakis, George G

    2015-10-01

    Dust pollution can negatively affect plant productivity in hot, dry and with high irradiance areas during summer. Soil or cement dust were applied on peach trees growing in a Mediterranean area with the above climatic characteristics. Soil and cement dust accumulation onto the leaves decreased the photosynthetically active radiation (PAR) available to the leaves without causing any shade effect. Soil and mainly cement dust deposition onto the leaves decreased stomatal conductance, photosynthetic and transpiration rates, and water use efficiency due possibly to stomatal blockage and other leaf cellular effects. In early autumn, rain events removed soil dust and leaf functions partly recovered, while cement dust created a crust partially remaining onto the leaves and causing more permanent stress. Leaf characteristics were differentially affected by the two dusts studied due to their different hydraulic properties. Leaf total chlorophyll decreased and total phenol content increased with dust accumulation late in the summer compared to control leaves due to intense oxidative stress. The two dusts did not cause serious metal imbalances to the leaves, except of lower leaf K content.

  19. Survival in soil of different toluene-degrading Pseudomonas strains after solvent shock.

    PubMed

    Huertas, M J; Duque, E; Marqués, S; Ramos, J L

    1998-01-01

    We assayed the tolerance to solvents of three toluene-degrading Pseudomonas putida strains and Pseudomonas mendocina KR1 in liquid and soil systems. P. putida DOT-T1 tolerated concentrations of heptane, propylbenzene, octanol, and toluene of at least 10% (vol/vol), while P. putida F1 and EEZ15 grew well in the presence of 1% (vol/vol) propylbenzene or 10% (vol/vol) heptane, but not in the presence of similar concentrations of octanol or toluene. P. mendocina KR1 grew only in the presence of heptane. All three P. putida strains were able to become established in a fluvisol soil from the Granada, Spain, area, whereas P. mendocina KR1 did not survive in this soil. The tolerance to organic solvents of all three P. putida strains was therefore assayed in soil. The addition to soil of 10% (vol/wt) heptane or 10% (vol/wt) propylbenzene did not affect the survival of the three P. putida strains. However, the addition of 10% (vol/wt) toluene led to an immediate decrease of several log units in the number of CFU per gram of soil for all of the strains, although P. putida F1 and DOT-T1 subsequently recovered. This recovery was influenced by the humidity of the soil and the incubation temperature. P. putida DOT-T1 recovered from the shock faster than P. putida F1; this allowed the former strain to become established at higher densities in polluted sites into which both strains had been introduced.

  20. Phenanthrene-degrader community dynamics in rhizosphere soil from a common annual grass

    SciTech Connect

    Miya, R.K.; Firestone, M.K.

    2000-04-01

    Enhanced rates of phenanthrene biodegradation were observed in rhizosphere soils planted with slender oat (Avena barbata Pott ex Link) compared with unplanted bulk soil controls. Soil microbial populations were characterized using a modified most probable number (MPN) method to determine quantitative shifts in heterotrophic and phenanthrene degrader communities while principal component analysis (PCA) of fatty acid methyl ester (FAME) data from isolated phenanthrene degraders was used to identify qualitative differences and degrader community diversity. The average heterotrophic bacterial population over time was about three times larger in rhizosphere soil than in bulk soil while phenanthrene degrading populations increased by as much as an order of magnitude between 24 and 28 days after planting (DAP). Thus, phenanthrene degraders were selectively enriched in rhizosphere soil compared with bulk soil. The greatest selection for degraders occurred during the later stages of plant development from 24 to 32 DAP. A PCA plot of the FAME data from phenanthrene degrader isolates indicated that the rhizosphere degraders were less diverse than bulk soil degraders. These results give some insight into the mechanisms responsible for enhanced biodegradation and selective degrader enrichment in Rhizosphere soils.

  1. Temporal changes in soil bacterial diversity and humic substances degradation in subarctic tundra soil.

    PubMed

    Park, Ha Ju; Chae, Namyi; Sul, Woo Jun; Lee, Bang Yong; Lee, Yoo Kyung; Kim, Dockyu

    2015-04-01

    Humic substances (HS), primarily humic acids (HA) and fulvic acids (FA), are the largest constituent of soil organic matter. In microcosm systems with subarctic HS-rich tundra soil (site AK 1-75; approximately 5.6 °C during the thawing period) from Council, Alaska, the HA content significantly decreased to 48% after a 99-day incubation at 5 °C as part of a biologically mediated process. Accordingly, levels of FA, a putative byproduct of HA degradation, consistently increased to 172% during an identical incubation process. Culture-independent microbial community analysis showed that during the microcosm experiments, the relative abundance of phyla Proteobacteria (bacteria) and Euryarchaeota (archaea) largely increased, indicating their involvement in HS degradation. When the indigenous bacteria in AK 1-75 were enriched in an artificial mineral medium spiked with HA, the changes in relative abundance were most conspicuous in Proteobacteria (from 60.2 to 79.0%), specifically Betaproteobacteria-related bacteria. One hundred twenty-two HA-degrading bacterial strains, primarily from the genera Paenibacillus (phylum Firmicutes) and Pseudomonas (class Gammaproteobacteria), were cultivated from AK 1-75 and nearby sites. Through culture-dependent analysis with these bacterial isolates, we observed increasing HS-degradation rates in parallel with rising temperatures in a range of 0 °C to 20 °C, with the most notable increase occurring at 8 °C compared to 6 °C. Our results indicate that, although microbial-mediated HS degradation occurs at temperature as low as 5 °C in tundra ecosystems, increasing soil temperature caused by global climate change could enhance HS degradation rates. Extending the thawing period could also increase degradation activity, thereby directly affecting nearby microbial communities and rhizosphere environments.

  2. Effect of elevated CO2 on degradation of azoxystrobin and soil microbial activity in rice soil.

    PubMed

    Manna, Suman; Singh, Neera; Singh, V P

    2013-04-01

    An experiment was conducted in open-top chambers (OTC) to study the effect of elevated CO2 (580 ± 20 μmol mol(-1)) on azoxystrobin degradation and soil microbial activities. Results indicated that elevated CO2 did not have any significant effect on the persistence of azoxystrobin in rice-planted soil. The half-life values for the azoxystrobin in rice soils were 20.3 days in control (rice grown at ambient CO2 outdoors), 19.3 days in rice grown under ambient CO2 atmosphere in OTC, and 17.5 days in rice grown under elevated CO2 atmosphere in OTC. Azoxystrobin acid was recovered as the only metabolite of azoxystrobin, but it did not accumulate in the soil/water and was further metabolized. Elevated CO2 enhanced soil microbial biomass (MBC) and alkaline phosphatase activity of soil. Compared with rice grown at ambient CO2 (both outdoors and in OTC), the soil MBC at elevated CO2 increased by twofold. Elevated CO2 did not affect dehydrogenase, fluorescein diacetate, and acid phosphatase activity. Azoxystrobin application to soils, both ambient and elevated CO2, inhibited alkaline phosphates activity, while no effect was observed on other enzymes. Slight increase (1.8-2 °C) in temperature inside OTC did not affect microbial parameters, as similar activities were recorded in rice grown outdoors and in OTC at ambient CO2. Higher MBC in soil at elevated CO2 could be attributed to increased carbon availability in the rhizosphere via plant metabolism and root secretion; however, it did not significantly increase azoxystrobin degradation, suggesting that pesticide degradation was not the result of soil MBC alone. Study suggested that increased CO2 levels following global warming might not adversely affect azoxystrobin degradation. However, global warming is a continuous and cumulative process, therefore, long-term studies are necessary to get more realistic assessment of global warming on fate of pesticide.

  3. Influence of pine or oak wood on the degradation of alachlor and metalaxyl in soil.

    PubMed

    Rodríguez-Cruz, M Sonia; Marín-Benito, Jesús M; Ordax, José M; Azejjel, Hanane; Sánchez-Martín, María J

    2012-03-01

    The objective of this work was to study the influence pine or oak wood added to soil as an amendment (5% w/w) had on the degradation rate of two pesticides, alachlor and metalaxyl, with different hydrophobic character. The formation of pesticide metabolites and the soil dehydrogenase activity in non-amended and amended soil samples were also monitored. The degradation of metalaxyl followed first-order kinetics, while the degradation of alachlor followed first-order or biphasic kinetics in the soil samples studied. The results indicated that the degradation rate was slower for metalaxyl than for alachlor, and for both pesticides followed the order: pine amended soil < oak amended soil < non-amended soil. The faster degradation rate in non-amended soil was attributed to the higher sorption of pesticides by wood amended soils. The alachlor ethane sulfonic acid (ESA), and two metalaxyl metabolites (2-[(2,6-dimethylphenyl)-methoxyacetylamino]-propionic acid and N-(2,6-dimethylphenyl)-2-methoxy-acetamide) were detected during the incubation period. Soil dehydrogenase activity recorded close values in non-amended and amended soil treated with alachlor, but it was higher in wood amended soil treated with metalaxyl. Pine and oak wood increase the immobilization of the pesticides studied, but they also limit their bioavailability in soil by decreasing their degradation rate in amended soil. Copyright © 2010 Elsevier Ltd. All rights reserved.

  4. [Environmental geochemical baseline of heavy metals in soils of the Ili river basin and pollution evaluation].

    PubMed

    Zhao, Xin-Ru; Nasier, Telajin; Cheng, Yong-Yi; Zhan, Jiang-Yu; Yang, Jian-Hong

    2014-06-01

    Environmental geochemical baseline models of Cu, Zn, Pb, As, Hg were established by standardized method in the ehernozem, chestnut soil, sierozem and saline soil from the Ili river valley region. The theoretical baseline values were calculated. Baseline factor pollution index evaluation method, environmental background value evaluation method and heavy metal cleanliness evaluation method were used to compare soil pollution degrees. The baseline factor pollution index evaluation showed that As pollution was the most prominent among the four typical types of soils within the river basin, with 7.14%, 9.76%, 7.50% of sampling points in chernozem, chestnut soil and sierozem reached the heavy pollution, respectively. 7.32% of sampling points of chestnut soil reached the permitted heavy metal Pb pollution index in the chestnut soil. The variation extent of As and Pb was the largest, indicating large human disturbance. Environmental background value evaluation showed that As was the main pollution element, followed by Cu, Zn and Pb. Heavy metal cleanliness evaluation showed that Cu, Zn and Pb were better than cleanliness level 2 and Hg was the of cleanliness level 1 in all four types of soils. As showed moderate pollution in sierozem, and it was of cleanliness level 2 or better in chernozem, chestnut soil and saline-alkali soil. Comparing the three evaluation systems, the baseline factor pollution index evaluation more comprehensively reflected the geochemical migration characteristics of elements and the soil formation processes, and the pollution assessment could be specific to the sampling points. The environmental background value evaluation neglected the natural migration of heavy metals and the deposition process in the soil since it was established on the regional background values. The main purpose of the heavy metal cleanliness evaluation was to evaluate the safety degree of soil environment.

  5. Catalytical degradation of relevant pollutants from waters using magnetic nanocatalysts

    NASA Astrophysics Data System (ADS)

    Nadejde, C.; Neamtu, M.; Schneider, R. J.; Hodoroaba, V.-D.; Ababei, G.; Panne, U.

    2015-10-01

    The catalytic efficiency of two magnetically responsive nanocatalysts was evaluated for the degradation of Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84) azo dyes using hydrogen peroxide as oxidant under very mild conditions (atmospheric pressure, room temperature). In order to obtain the nanocatalysts, the surface of magnetite (Fe3O4) nanoparticles, prepared by a co-precipitation method, was further modified with ferrous oxalate, a highly sensitive non-hazardous reducing agent. The sensitized nanomaterials were characterized by X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy and vibrating sample magnetometry, and used in the catalytic wet hydrogen peroxide oxidation (CWHPO) of RB5 and RY84, in laboratory-scale experiments. The effect of important variables such as catalyst dosage, H2O2 concentration, and contact time was studied in the dye degradation kinetics. The results showed that it was possible to remove up to 99.7% dye in the presence of 20 mM H2O2 after 240 min of oxidation for a catalyst concentration of 10 g L-1 at 25 °C and initial pH value of 9.0. CWHPO of reactive dyes using sensitized magnetic nanocatalysts can be a suitable pre-treatment method for complete decolorization of effluents from textile dyeing and finishing processes, once the optimum operating conditions are established.

  6. Estimations of soil fertility in physically degraded agricultural soils through selective accounting of fine earth and gravel fractions

    NASA Astrophysics Data System (ADS)

    Nagaraja, Mavinakoppa S.; Bhardwaj, Ajay Kumar; Prabhakara Reddy, G. V.; Srinivasamurthy, Chilakunda A.; Kumar, Sandeep

    2016-06-01

    Soil fertility and organic carbon (C) stock estimations are crucial to soil management, especially that of degraded soils, for productive agricultural use and in soil C sequestration studies. Currently, estimations based on generalized soil mass (hectare furrow basis) or bulk density are used which may be suitable for normal agricultural soils, but not for degraded soils. In this study, soil organic C, available nitrogen (N), available phosphorus (P2O5) and available potassium (K2O), and their stocks were estimated using three methods: (i) generalized soil mass (GSM, 2 million kg ha-1 furrow soil), (ii) bulk-density-based soil mass (BDSM) and (iii) the proportion of fine earth volume (FEV) method, for soils sampled from physically degraded lands in the eastern dry zone of Karnataka State in India. Comparative analyses using these methods revealed that the soil organic C, N, P2O and K2O stocks determined by using BDSM were higher than those determined by the GSM method. The soil organic C values were the lowest in the FEV method. The GSM method overestimated soil organic C, N, P2O and K2O by 9.3-72.1, 9.5-72.3, 7.1-66.6 and 9.2-72.3 %, respectively, compared to FEV-based estimations for physically degraded soils. The differences among the three methods of estimation were lower in soils with low gravel content and increased with an increase in gravel volume. There was overestimation of soil organic C and soil fertility with GSM and BDSM methods. A reassessment of methods of estimation was, therefore, attempted to provide fair estimates for land development projects in degraded lands.

  7. The use of acute and chronic bioassays to determine the ecological risk and bioremediation efficiency of oil-polluted soils.

    PubMed

    van Gestel, C A; van der Waarde, J J; Derksen, J G; van der Hoek, E E; Veul, M F; Bouwens, S; Rusch, B; Kronenburg, R; Stokman, G N

    2001-07-01

    To compare the effectiveness of acute and chronic bioassays for the ecological risk assessment of polluted soils, soil samples from a site with an historical mineral oil contamination (< 50-3,300 mg oil/kg dry soil) at the Petroleum Harbour in Amsterdam, The Netherlands, were screened for ecological effects using acute and chronic bioassays. A two-step 0.001 M Ca(NO3)2 extraction at a final solution-to-soil ratio of 1:1 was used to prepare extracts for the acute bioassays. Acute bioassays (< or = 5 d) applied to the 0.001 M Ca(NO3)2 extracts from the polluted and reference soils included growth tests with bacteria (Bacillus sp.), algae (Raphidocelis subcapitata), and plants (Lactuca sativa), immobility tests with nematodes (Plectus acuminatus), springtails (Folsomia candida), and cladocerans (Daphnia magna), and the Microtox test (Vibrio fischeri). Chronic bioassays (four weeks) performed on the same soil samples included tests with L. sativa, F. candida, and earthworms (Eisenia fetida) and the bait-lamina test (substrate consumption). The acute bioassays on Microtox showed a response that corresponded with the level of oil pollution. All other acute bioassays did not show such a consistent response, probably because pollutant levels were too low to cause acute effects. All chronic bioassays showed sublethal responses according to the contaminant levels (oil and in some soils also metals). This shows that chronic bioassays on soil samples are more sensitive in assessing the toxicity of mineral oil contamination in soil than acute bioassays on soil extracts. A pilot scale bioremediation study on soils taken from the two most polluted sites and a control site showed a rapid decline of oil concentrations to reach a stable level within eight weeks. Acute bioassays applied to the soils, using Microtox, algae, and D. magna, and chronic bioassays, using plants, Collembola, earthworms, and bait-lamina consumption, in all cases showed a rapid reduction of toxicity, which

  8. Contribution of soil fauna to soil functioning in degraded environments: a multidisciplinary approach

    NASA Astrophysics Data System (ADS)

    Gargiulo, Laura; Mele, Giacomo; Moradi, Jabbar; Kukla, Jaroslav; Jandová, Kateřina; Frouz, Jan

    2016-04-01

    The restoration of the soil functions is essential for the recovery of highly degraded sites and, consequently, the study of the soil fauna role in the soil development in such environments has great potential from a practical point of view. The soils of the post-mining sites represent unique models for the study of the natural ecological succession because mining creates similar environments characterized by the same substrate, but by different ages according to the year of closure of mines. The aim of this work was to assess the contribution of different species of macrofauna on the evolution of soil structure and on the composition and activity of the microbial community in soil samples subjected to ecological restoration or characterized by spontaneous ecological succession. For this purpose, an experimental test was carried out in two sites characterized by different post-mining conditions: 1) natural succession, 2) reclamation with planting trees. These sites are located in the post-mining area of Sokolov (Czech Republic). For the experimental test repacked soil cores were prepared in laboratory with sieved soil sampled from the two sites. The soil cores were prepared maintaining the sequence of soil horizons present in the field. These samples were inoculated separately with two genera of earthworms (Lumbricus and Aporrectodea) and two of centipedes (Julida and Polydesmus). In particular, based on their body size, were inoculated for each cylinder 2 individuals of millipedes, 1 individual of Lumbricus and 4 individuals of Aporrectodea. For each treatment and for control samples 5 replicates were prepared and all samples were incubated in field for 1 month in the two original sampling sites. After the incubation the samples were removed from the field and transported in laboratory in order to perform the analysis of microbial respiration, of PLFA (phospholipid-derived fatty acids) and ergosterol contents and finally for the characterization of soil structure

  9. Enhancing phenanthrene biomineralization in a polluted soil using gaseous toluene as a cosubstrate.

    PubMed

    Ortiz, Irmene; Auria, Richard; Sigoillot, Jean-Claude; Revah, Sergio

    2003-02-15

    Laboratory experiments were conducted to study the potential of adding gaseous toluene, as a readily degradable carbon source, to enhance phenanthrene mineralization in polluted soil (1,000 mg/kg(dry soil)) aged for 400 days. Experiments were conducted in 0.5-L column reactors packed with a mixture of (80:20 w(wet)/w(wet)) spiked soil and vermiculite and fed with 1 g m(-3)reactor h(-1) toluene load in air. Removal efficiencies of 100% for toluene and greater than 95% for phenanthrene were obtained in 190 h. Evolved CO2 showed that phenanthrene mineralization increased from 39% to 86% in columns treated with gaseous toluene. Phthalic acid was identified as the principal soluble intermediate, which accumulated when no toluene was added. Increased phenanthrene uptake and mineralization with toluene can be attributed to increased biomass and the induction of enzymes involved in the intermediate mineralization. In microcosm experiments, phthalic acid mineralization increased from 19% to 81% within 50 h in the presence of toluene. Experiments with 14C-labeled phenanthrene confirmed the enhancement of phenanthrene mineralization from 45% to 83% in 385 h with toluene as a second carbon source. The results indicate thatthe addition of an appropriate gaseous cosubstrate could be an adequate strategy to enhance mineralization of PAHs in soil.

  10. Microbial Degradation of Acetamiprid by Ochrobactrum sp. D-12 Isolated from Contaminated Soil

    PubMed Central

    Wang, Guangli; Chen, Xiao; Yue, Wenlong; Zhang, Hui; Li, Feng; Xiong, Minghua

    2013-01-01

    Neonicotinoid insecticides are one of the most important commercial insecticides used worldwide. The potential toxicity of the residues present in environment to humans has received considerable attention. In this study, a novel Ochrobactrum sp. strain D-12 capable of using acetamiprid as the sole carbon source as well as energy, nitrogen source for growth was isolated and identified from polluted agricultural soil. Strain D-12 was able to completely degrade acetamiprid with initial concentrations of 0–3000 mg·L−1 within 48 h. Haldane inhibition model was used to fit the special degradation rate at different initial concentrations, and the parameters qmax, Ks and Ki were determined to be 0.6394 (6 h)−1, 50.96 mg·L−1 and 1879 mg·L−1, respectively. The strain was found highly effective in degrading acetamiprid over a wide range of temperatures (25–35°C) and pH (6–8). The effects of co-substrates on the degradation efficiency of acetamiprid were investigated. The results indicated that exogenously supplied glucose and ammonium chloride could slightly enhance the biodegradation efficiency, but even more addition of glucose or ammonium chloride delayed the biodegradation. In addition, one metabolic intermediate identified as N-methyl-(6-chloro-3-pyridyl)methylamine formed during the degradation of acetamiprid mediated by strain D-12 was captured by LC-MS, allowing a degradation pathway for acetamiprid to be proposed. This study suggests the bacterium could be a promising candidate for remediation of environments affected by acetamiprid. PMID:24386105

  11. Isolation and Characterization of Phenanthrene Degrading Bacteria from Diesel Fuel-Contaminated Antarctic Soils

    PubMed Central

    Gran-Scheuch, Alejandro; Fuentes, Edwar; Bravo, Denisse M.; Jiménez, Juan Cristobal; Pérez-Donoso, José M.

    2017-01-01

    Antarctica is an attractive target for human exploration and scientific investigation, however the negative effects of human activity on this continent are long lasting and can have serious consequences on the native ecosystem. Various areas of Antarctica have been contaminated with diesel fuel, which contains harmful compounds such as heavy metals and polycyclic aromatic hydrocarbons (PAH). Bioremediation of PAHs by the activity of microorganisms is an ecological, economical, and safe decontamination approach. Since the introduction of foreign organisms into the Antarctica is prohibited, it is key to discover native bacteria that can be used for diesel bioremediation. By following the degradation of the PAH phenanthrene, we isolated 53 PAH metabolizing bacteria from diesel contaminated Antarctic soil samples, with three of these isolates exhibiting a high phenanthrene degrading capacity. In particular, the Sphingobium xenophagum D43FB isolate showed the highest phenanthrene degradation ability, generating up to 95% degradation of initial phenanthrene. D43FB can also degrade phenanthrene in the presence of its usual co-pollutant, the heavy metal cadmium, and showed the ability to grow using diesel-fuel as a sole carbon source. Microtiter plate assays and SEM analysis revealed that S. xenophagum D43FB exhibits the ability to form biofilms and can directly adhere to phenanthrene crystals. Genome sequencing analysis also revealed the presence of several genes involved in PAH degradation and heavy metal resistance in the D43FB genome. Altogether, these results demonstrate that S. xenophagum D43FB shows promising potential for its application in the bioremediation of diesel fuel contaminated-Antarctic ecosystems. PMID:28894442

  12. Isolation and Characterization of Phenanthrene Degrading Bacteria from Diesel Fuel-Contaminated Antarctic Soils.

    PubMed

    Gran-Scheuch, Alejandro; Fuentes, Edwar; Bravo, Denisse M; Jiménez, Juan Cristobal; Pérez-Donoso, José M

    2017-01-01

    Antarctica is an attractive target for human exploration and scientific investigation, however the negative effects of human activity on this continent are long lasting and can have serious consequences on the native ecosystem. Various areas of Antarctica have been contaminated with diesel fuel, which contains harmful compounds such as heavy metals and polycyclic aromatic hydrocarbons (PAH). Bioremediation of PAHs by the activity of microorganisms is an ecological, economical, and safe decontamination approach. Since the introduction of foreign organisms into the Antarctica is prohibited, it is key to discover native bacteria that can be used for diesel bioremediation. By following the degradation of the PAH phenanthrene, we isolated 53 PAH metabolizing bacteria from diesel contaminated Antarctic soil samples, with three of these isolates exhibiting a high phenanthrene degrading capacity. In particular, the Sphingobium xenophagum D43FB isolate showed the highest phenanthrene degradation ability, generating up to 95% degradation of initial phenanthrene. D43FB can also degrade phenanthrene in the presence of its usual co-pollutant, the heavy metal cadmium, and showed the ability to grow using diesel-fuel as a sole carbon source. Microtiter plate assays and SEM analysis revealed that S. xenophagum D43FB exhibits the ability to form biofilms and can directly adhere to phenanthrene crystals. Genome sequencing analysis also revealed the presence of several genes involved in PAH degradation and heavy metal resistance in the D43FB genome. Altogether, these results demonstrate that S. xenophagum D43FB shows promising potential for its application in the bioremediation of diesel fuel contaminated-Antarctic ecosystems.

  13. Mangrove soils in removing pollutants from municipal wastewater of different salinities

    SciTech Connect

    Tam, N.F.Y.; Wong, Y.S.

    1999-03-01

    Soil leaching experiments were conducted to assess the capacity of mangrove soils in purifying synthetic wastewater containing pollutant concentrations four times of that found in local municipal sewage and of two salinities (fresh vs. saline water). Results on leachate nutrient and heavy metal concentrations reveal that the mangrove soils were capable of removing certain amount of pollutants from wastewater, and the removal efficiency varied between pollutants. The soils were most effective in retaining heavy metals such as Cu but were less effective for Mn and Zn. Similarly, the wastewater-borne NH{sub 4}{sup +} was more easily leached than P. The soil data show that most pollutants were accumulated in the top layer of the soil tray, with little downward migration. Differences between treated and control soil nutrient and heavy metal concentrations were not found in the soil masses below the surface 1.5 cm. In the surface layer, the mangrove soils treated with wastewater had significantly higher concentrations of NH{sub 4}{sup +}-N, total and extractable P, total and extractable Cu, Cd, Zn and Mn. On the other hand, there was no significant elevation in total nitrogen content in mangrove soils treated with wastewater when compared with the control. Soils receiving wastewater prepared in deionized water (fresh) had slightly higher pollutant concentrations, and larger enrichment factors than that treated with saline wastewater. These results suggest that mangrove soils could retain pollutants from wastewater but its efficiency would slightly be affected by salinity.

  14. Ecotoxicological assessment of soils polluted with chemical waste from lindane production: Use of bacterial communities and earthworms as bioremediation tools.

    PubMed

    Muñiz, Selene; Gonzalvo, Pilar; Valdehita, Ana; Molina-Molina, José Manuel; Navas, José María; Olea, Nicolás; Fernández-Cascán, Jesús; Navarro, Enrique

    2017-11-01

    An ecotoxicological survey of soils that were polluted with wastes from lindane (γ-HCH) production assessed the effects of organochlorine compounds on the metabolism of microbial communities and the toxicity of these compounds to a native earthworm (Allolobophora chlorotica). Furthermore, the bioremediation role of earthworms as facilitators of soil washing and the microbial degradation of these organic pollutants were also studied. Soil samples that presented the highest concentrations of ε-HCH, 2,4,6-trichlorophenol, pentachlorobenzene and γ-HCH were extremely toxic to earthworms in the short term, causing the death of almost half of the population. In addition, these soils inhibited the heterotrophic metabolic activity of the microbial community. These highly polluted samples also presented substances that were able to activate cellular detoxification mechanisms (measured as EROD and BFCOD activities), as well as compounds that were able to cause endocrine disruption. A few days of earthworm activity increased the extractability of HCH isomers (e.g., γ-HCH), facilitating the biodegradation of organochlorine compounds and reducing the intensity of endocrine disruption in soils that had low or medium contamination levels. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. A simple strategy for investigating the diversity and hydrocarbon degradation abilities of cultivable bacteria from contaminated soil.

    PubMed

    Bučková, Maria; Puškarová, Andrea; Chovanová, Katarína; Kraková, Lucia; Ferianc, Peter; Pangallo, Domenico

    2013-06-01

    The use of indigenous bacterial strains is a valuable bioremediation strategy for cleaning the environment from hydrocarbon pollutants. The isolation and selection of hydrocarbon-degrading bacteria is therefore crucial for obtaining the most promising strains for site decontamination. Two different media, a minimal medium supplemented with a mixture of polycyclic aromatic hydrocarbons and a MS medium supplemented with triphenyltetrazolium chloride, were used for the isolation of bacterial strains from two hydrocarbon contaminated soils and from their enrichment phases. The hydrocarbon degradation abilities of these bacterial isolates were easily and rapidly assessed using the 2,6-dichlorophenol indophenol assay. The diversity of the bacterial communities isolated from these two soil samples and from their enrichment phases was evaluated by the combination of a bacterial clustering method, fluorescence ITS-PCR, and bacterial identification by 16S rRNA sequencing. Different PCR-based assays were performed in order to detect the genes responsible for hydrocarbon degradation. The best hydrocarbon-degrading bacteria, including Arthrobacter sp., Enterobacter sp., Sphingomonas sp., Pseudomonas koreensis, Pseudomonas putida and Pseudomonas plecoglossicida, were isolated directly from the soil samples on minimal medium. The nahAc gene was detected only in 13 Gram-negative isolates and the sequences of nahAc-like genes were obtained from Enterobacter, Stenotrophomonas, Pseudomonas brenneri, Pseudomonas entomophila and P. koreensis strains. The combination of isolation on minimal medium with the 2,6-dichlorophenol indophenol assay was effective in selecting different hydrocarbon-degrading strains from 353 isolates.

  16. A Case Study of Petroleum Degradation in Different Soil Textural Classes.

    PubMed

    Kogbara, Reginald B; Ayotamuno, Josiah M; Worlu, Daniel C; Fubara-Manuel, Isoteim

    2016-01-01

    Patents have been granted for a number of techniques for petroleum biodegradation including use of micro-organisms for degradation of hydrocarbon-based substances and for hydrocarbon degradation in oil reservoirs, but there is a dearth of information on hydrocarbon degradation in different soil textures. Hence, this work investigated the effects of different soil textures on degradation of petroleum hydrocarbons during a six-week period. Five soil textural classes commonly found in Port Harcourt metropolis, Nigeria, namely sand, loamy sand, sandy loam, silty clay and clay, were employed. The soils were contaminated with the same amount of crude oil and then remediated by biostimulation. Selected soil properties were monitored over time. Bacterial numbers declined significantly in the fine soil textures after petroleum contamination, but were either unaffected or increased significantly in the coarser soil textures. Hydrocarbon losses ranged from 42% - 99%; the sandy loam had the highest, while the clay soil had the least total hydrocarbon content (THC) reduction. The total heterotrophic bacterial (THB) counts generally corroborated the THC results. Fold increase in bacterial numbers due to remediation treatment decreased with increasing clay content. The results suggest that higher sand than clay content of soil favours faster hydrocarbon degradation. Hydrocarbon degradation efficiency increased with silt content among soil groupings such as fine and coarse soils but not necessarily with increasing silt content of soil. Thus, there seems to be cut-off sand and clay contents in soil at which the effect of the silt content becomes significant.

  17. Isolation and characterisation of polychlorinated biphenyl (PCB) degrading fungi from a historically contaminated soil

    PubMed Central

    Tigini, Valeria; Prigione, Valeria; Di Toro, Sara; Fava, Fabio; Varese, Giovanna C

    2009-01-01

    Background Polychlorinated biphenyls (PCBs) are widespread toxic pollutants. Bioremediation might be an effective, cost competitive and environment-friendly solution for remediating environmental matrices contaminated by PCBs but it is still unsatisfactory, mostly for the limited biodegradation potential of bacteria involved in the processes. Very little is known about mitosporic fungi potential in PCB bioremediation and their occurrence in actual site historically contaminated soils. In the present study, we characterised the native mycoflora of an aged dump site soil contaminated by about 0.9 g kg-1 of Aroclor 1260 PCBs and its changing after aerobic biotreatment with a commercial complex source of bacteria and fungi. Fungi isolated from the soil resulting from 120 days of treatment were screened for their ability to adsorb or metabolise 3 target PCBs. Results The original contaminated soil contained low loads of few fungal species mostly belonging to the Scedosporium, Penicillium and Aspergillus genera. The fungal load and biodiversity generally decreased throughout the aerobic treatment. None of the 21 strains isolated from the treated soil were able to grow on biphenyl (200 mg L-1) or a mixture of 2-chlorobiphenyl, 4,4'-dichlorobiphenyl and 2,2',5,5'-tetrachlorobiphenyl (20 mg L-1 each) as sole carbon sources. However, 16 of them grew in a mineral medium containing the same PCBs mixture and glucose (10 g L-1). Five of the 6 isolates, which displayed the faster and more extensive growth under the latter conditions, were found to degrade the 3 PCBs apparently without the involvement of ligninolytic enzymes; they were identified as Penicillium chrysogenum, Scedosporium apiospermum, Penicillium digitatum and Fusarium solani. They are the first PCB degrading strains of such species reported so far in the literature. Conclusion The native mycoflora of the actual site aged heavily contaminated soil was mainly constituted by genera often reported as able to biodegrade

  18. [Biological degradation of sticky-gene compositions in different type soils].

    PubMed

    Votselko, S K; Iamborko, N A; Litvinchuk, O A; Dankevitch, L A; Shkatula, Iu N

    2012-01-01

    The ability of native microbial associations from different types of soils to degrade sticky-gene composition which were created on the EPAA basis have been determined. The ecological safety and harmlessness of sticky-gene composition, its slow degradation by soils microorganisms and providing long-term influence (impact) of preparations introduced on plants protection have been shown. The conditions of gray forest and sod podzol soil are the most favorable for the sticky-gene composition degradation. Sticky-gene composition degradation goes slower in sandy soil conditions.

  19. Impact of repeated single-metal and multi-metal pollution events on soil quality.

    PubMed

    Burges, Aritz; Epelde, Lur; Garbisu, Carlos

    2015-02-01

    Most frequently, soil metal pollution results from the occurrence of repeated single-metal and, above all, multi-metal pollution events, with concomitant adverse consequences for soil quality. Therefore, in this study, we evaluated the impact of repeated single-metal and multi-metal (Cd, Pb, Cu, Zn) pollution events on soil quality, as reflected by the values of a variety of soil microbial parameters with potential as bioindicators of soil functioning. Specifically, parameters of microbial activity (potentially mineralizable nitrogen, β-glucosidase and acid phosphatase activity) and biomass (fungal and bacterial gene abundance by RT-qPCR) were determined, in the artificially metal-polluted soil samples, at regular intervals over a period of 26 weeks. Similarly, we studied the evolution over time of CaCl2-extractable metal fractions, in order to estimate metal bioavailability in soil. Different metals showed different values of bioavailability and relative bioavailability ([metal]bio/[metal]tot) in soil throughout the experiment, under both repeated single-metal and multi-metal pollution events. Both repeated Zn-pollution and multi-metal pollution events led to a significant reduction in the values of acid phosphatase activity, and bacterial and fungal gene abundance, reflecting the negative impact of these repeated events on soil microbial activity and biomass, and, hence, soil quality.

  20. Degradation of iprodione by a soil Arthrobacter-like strain.

    PubMed Central

    Athiel, P; Alfizar; Mercadier, C; Vega, D; Bastide, J; Davet, P; Brunel, B; Cleyet-Marel, J C

    1995-01-01

    A bacterial strain able to transform iprodione was isolated from a fast iprodione-degrading soil by enrichment procedures. Transformation was detected through 3,5-dichloroaniline production as measured by a rapid colorimetric method. The strain, MA6, was tentatively identified as an Arthrobacter sp. When it was incubated with MA6 in a minimum mineral medium (pH 6.5), iprodione (8.8 mumol/liter) was transformed into two major metabolites that were identified by high-performance liquid chromatography analysis: 3,5-dichlorophenylcarboximide (metabolite 1) and (3,5-dichlorophenylurea) acetic acid (metabolite 2), which was produced after ring cleavage of the former product. These products were synthesized in the laboratory and compared with metabolites 1 and 2 which were formed during iprodione degradation. Small quantities of 3,5-dichloroaniline also appeared in the bacterial culture but did not substantially increase between the first and second days of incubation. In contrast, in the sterile control medium, iprodione was spontaneously transformed into hydantoic acid and an iprodione isomer. Chemical and biological transformations of iprodione seem to occur through two different pathways. One biological degradation pathway is proposed. PMID:7574630

  1. Degradation of pyridine by Micrococcus luteus isolated from soil

    SciTech Connect

    Sims, G.K.; Sommers, L.E.; Konopka, A.

    1986-05-01

    An organism capable of growth on pyridine was isolated from soil by enrichment culture techniques and identified as Micrococcus luteus. The organism oxidized pyridine for energy and released N contained in the pyridine ring as ammonium. The organism could not grow on mono- or disubstituted pyridinecarboxylic acids or hydroxy-, chloro-, amino-, or methylpyridines. Cell extracts of M. luteus could not degrade pyridine, 2-, 3-, or 4-hydroxypyridines or 2,3-dihydroxypyridine, regardless of added cofactors or cell particulate fraction. The organism had a NAD-linked succinate-semialdehyde dehydrogenase which was induced by pyridine. Cell extracts of M. luteus had constitutive amidase activity, and washed cells degraded formate and formamide without a lag. These data are consistent with a previously reported pathway for pyridine metabolism by species of Bacillus, Brevibacterium, and Corynebacterium. Cells of M. luteus were permeable to pyridinecarboxylic acids, monohydroxypyridines, 2,3-dihydroxypyridine, and monoamino- and methylpyridines. The results provide new evidence that the metabolism of pyridine by microorganisms does not require initial hydroxylation of the ring and that permeability barriers do not account for the extremely limited range of substrate isomers used by pyridine degraders.

  2. Degradation of Pyridine by Micrococcus luteus Isolated from Soil

    PubMed Central

    Sims, Gerald K.; Sommers, Lee E.; Konopka, Allan

    1986-01-01

    An organism capable of growth on pyridine was isolated from soil by enrichment culture techniques and identified as Micrococcus luteus. The organism oxidized pyridine for energy and released N contained in the pyridine ring as ammonium. The organism could not grow on mono- or disubstituted pyridinecarboxylic acids or hydroxy-, chloro-, amino-, or methylpyridines. Cell extracts of M. luteus could not degrade pyridine, 2-, 3-, or 4-hydroxypyridines or 2,3-dihydroxypyridine, regardless of added cofactors or cell particulate fraction. The organism had a NAD-linked succinate-semialdehyde dehydrogenase which was induced by pyridine. Cell extracts of M. luteus had constitutive amidase activity, and washed cells degraded formate and formamide without a lag. These data are consistent with a previously reported pathway for pyridine metabolism by species of Bacillus, Brevibacterium, and Corynebacterium. Cells of M. luteus were permeable to pyridinecarboxylic acids, monohydroxypyridines, 2,3-dihydroxypyridine, and monoamino- and methylpyridines. The results provide new evidence that the metabolism of pyridine by microorganisms does not require initial hydroxylation of the ring and that permeability barriers do not account for the extremely limited range of substrate isomers used by pyridine degraders. PMID:16347070

  3. Effective degradation of organic water pollutants by atmospheric non-thermal plasma torch and analysis of degradation process.

    PubMed

    Bansode, Avinash S; More, Supriya E; Siddiqui, Ejaz Ahmad; Satpute, Shruti; Ahmad, Absar; Bhoraskar, Sudha V; Mathe, Vikas L

    2017-01-01

    The paper reports the use of atmospheric non-thermal plasma torch as a catalyst for degradation of various organic pollutants dissolved in water. A flow of He mixed with air was used to produce the dielectric barrier discharge (DBD), at the tip of the torch, using pulsed electric excitation at 12 kV. The torch, operated at a power of 750 mW/mm(2), was seen to completely degrade the aqueous solutions of the pollutants namely methylene blue (MB), methyl orange (MO) and rhodamine-B (RB), at around 10(-4) M concentrations, the concentration of polluants is one order higher than of routinely used heterogeneous photocatalytic reactions, within 10 min of irradiation time at room temperature. UV Visible spectra of the organic dye molecules, monitored after different intervals of plasma-irradiation, ranging between 1 and 10 min, have been used as tools to quantify their sequential degradation. Further, instead of using He, only air was used to form plasma plume and used for degradation of organic dye which follow similar trend as that of He plasma. Further, Liquid Chromatography Mass Spectroscopy (LCMS) technique has been used to understand degradation pathway of methylene blue (MB) as a representative case. Total organic carbon (TOC) measurements indicates significant decrease in its content as a function of duration of plasma exposure onto methylene blue as a representative case. Toxicity studies were carried out onto Gram negative Escherichia coli. This indicated that methylene blue, without plasma treatment, shows growth inhibition, whereas with plasma treatment no inhibition was observed.

  4. Experimental study on effect of anion surfactant on degradation rate of aldicarb in soil.

    PubMed

    Liu, Guangliang; Dai, Shugui; Qian, Yun; Gan, Quan

    2003-07-01

    Degradation kinetics of aldicarb [2-methyl-2-(methylthio) propionaldehyde O-(methyl carbamoyl) oxime] in surface and subsurface soil containing different levels of sodium dodecylbenzenesulfonate (SDBS) were determined to understand complex effect of SDBS on aldicarb degradation process. The results showed that degradation curves of aldicarb in soil can be described with first order kinetics formula and the degradation rate constant. k (d(-1)), in surface soil was larger than that in subsurface soil. SDBS can accelerate the degradation of aldicarb in soil and there was a good linear relationship between degradation rate constant and the logarithm of SDBS concentration. The possible reasons were that SDBS could change pH value of soil, have solubilization effect on aldicarb, and be used as carbon source of microorganisms. But SDBS had a larger promotion to the degradation of aldicarb in surface than in subsurface soil. When SDBS concentration was 1000 mg/kg of dried soil the first order degradation rate constant of aldicarb could be increased by 56.6 percent in surface soil and by 27.6 percent in subsurface soil, respectively.

  5. Evidence of degradation of polybrominated biphenyls in soil samples from Michigan

    SciTech Connect

    Hill, R.H. Jr.; Patterson, D.G.; Orti, D.L.; Holler, J.S.; Needham, L.L.; Sirmans, S.L.; Liddle, J.A.

    1982-01-01

    Soil samples obtained from the former polybrominated biphenyls (PBB) manufacturing site in Michigan were analyzed by gas chromatography and gas chromatography with mass spectrometric detection. The results indicate significant degradation of the PBB residue in the soil sample. The soil sample with the highest concentration of PBB had the greatest degree of degradation. Principal degradation products include 2,3', 4,4', 5-pentabromobiphenyl, 2,2', 4,4', 5-pentabromobiphenyl and two unidentified tetrabromobiphenyls. The degradation pattern observed supports a photochemical decomposition mechanism. These degraded residues may be more toxic than the original Firemaster residues. The implications of the results are discussed.

  6. Development of a composite soil degradation assessment index for cocoa agroecosystems in southwestern Nigeria

    NASA Astrophysics Data System (ADS)

    Adenrele Adeniyi, Sunday; de Clercq, Willem Petrus; van Niekerk, Adriaan

    2017-08-01

    Cocoa agroecosystems are a major land-use type in the tropical rainforest belt of West Africa, reportedly associated with several ecological changes, including soil degradation. This study aims to develop a composite soil degradation assessment index (CSDI) for determining the degradation level of cocoa soils under smallholder agroecosystems of southwestern Nigeria. Plots where natural forests have been converted to cocoa agroecosystems of ages 1-10, 11-40, and 41-80 years, respectively representing young cocoa plantations (YCPs), mature cocoa plantations (MCPs), and senescent cocoa plantations (SCPs), were identified to represent the biological cycle of the cocoa tree. Soil samples were collected at a depth of 0 to 20 cm in each plot and analysed in terms of their physical, chemical, and biological properties. Factor analysis of soil data revealed four major interacting soil degradation processes: decline in soil nutrients, loss of soil organic matter, increase in soil acidity, and the breakdown of soil textural characteristics over time. These processes were represented by eight soil properties (extractable zinc, silt, soil organic matter (SOM), cation exchange capacity (CEC), available phosphorus, total porosity, pH, and clay content). These soil properties were subjected to forward stepwise discriminant analysis (STEPDA), and the result showed that four soil properties (extractable zinc, cation exchange capacity, SOM, and clay content) are the most useful in separating the studied soils into YCP, MCP, and SCP. In this way, we have sufficiently eliminated redundancy in the final selection of soil degradation indicators. Based on these four soil parameters, a CSDI was developed and used to classify selected cocoa soils into three different classes of degradation. The results revealed that 65 % of the selected cocoa farms are moderately degraded, while 18 % have a high degradation status. The numerical value of the CSDI as an objective index of soil degradation

  7. Early-warning signals for catastrophic soil degradation

    NASA Astrophysics Data System (ADS)

    Karssenberg, Derek

    2010-05-01

    Many earth systems have critical thresholds at which the system shifts abruptly from one state to another. Such critical transitions have been described, among others, for climate, vegetation, animal populations, and geomorphology. Predicting the timing of critical transitions before they are reached is of importance because of the large impact on nature and society associated with the transition. However, it is notably difficult to predict the timing of a transition. This is because the state variables of the system show little change before the threshold is reached. As a result, the precision of field observations is often too low to provide predictions of the timing of a transition. A possible solution is the use of spatio-temporal patterns in state variables as leading indicators of a transition. It is becoming clear that the critically slowing down of a system causes spatio-temporal autocorrelation and variance to increase before the transition. Thus, spatio-temporal patterns are important candidates for early-warning signals. In this research we will show that these early-warning signals also exist in geomorphological systems. We consider a modelled vegetation-soil system under a gradually increasing grazing pressure causing an abrupt shift towards extensive soil degradation. It is shown that changes in spatio-temporal patterns occur well ahead of this catastrophic transition. A distributed model describing the coupled processes of vegetation growth and geomorphological denudation is adapted. The model uses well-studied simple process representations for vegetation and geomorphology. A logistic growth model calculates vegetation cover as a function of grazing pressure and vegetation growth rate. Evolution of the soil thickness is modelled by soil creep and wash processes, as a function of net rain reaching the surface. The vegetation and soil system are coupled by 1) decreasing vegetation growth with decreasing soil thickness and 2) increasing soil wash with

  8. Aquifer microcosms and in situ methods to test the fate and function of pollutant-degrading microorganisms

    SciTech Connect

    Krumme, M.L.; Dwyer, D. . Inst. fuer Biotechnologie); Thiem, S.M.; Tiedje, J.M. ); Smith, R.L. )

    1990-01-01

    Little information is available on groundwater microorganism ecology, and specifically on the distribution and biochemical diversity of pollution degrading microorganisms in the aquifer. While the introduction of nutrients and electron acceptors may stimulate natural populations to degrade certain pollutants, low levels of pollutants and complex mixtures of pollutants may require the modification of natural populations through selective pressure or by means of genetic engineering. This study was designed to address these issues by examining three populations of substituted aromatic compound-degraders: an indigenous population, an introduced degrader, and a genetically engineered microorganism (GEM) in the environmental conditions of a sand and gravel aquifer. The goals of this study are to gain field experience on the fate and function of pollutant-degrading organisms in the aquifer and to evaluate column microcosms and survival chambers as tools for predicting the fate and function of selected and modified bacterial strains as appropriate aquifer bioremediation agents. 6 figs.

  9. Estimating the Pollution Risk of Cadmium in Soil Using a Composite Soil Environmental Quality Standard

    PubMed Central

    Huang, Biao; Zhao, Yongcun

    2014-01-01

    Estimating standard-exceeding probabilities of toxic metals in soil is crucial for environmental evaluation. Because soil pH and land use types have strong effects on the bioavailability of trace metals in soil, they were taken into account by some environmental protection agencies in making composite soil environmental quality standards (SEQSs) that contain multiple metal thresholds under different pH and land use conditions. This study proposed a method for estimating the standard-exceeding probability map of soil cadmium using a composite SEQS. The spatial variability and uncertainty of soil pH and site-specific land use type were incorporated through simulated realizations by sequential Gaussian simulation. A case study was conducted using a sample data set from a 150 km2 area in Wuhan City and the composite SEQS for cadmium, recently set by the State Environmental Protection Administration of China. The method may be useful for evaluating the pollution risks of trace metals in soil with composite SEQSs. PMID:24672364

  10. Estimating the pollution risk of cadmium in soil using a composite soil environmental quality standard.

    PubMed

    Qu, Mingkai; Li, Weidong; Zhang, Chuanrong; Huang, Biao; Zhao, Yongcun

    2014-01-01

    Estimating standard-exceeding probabilities of toxic metals in soil is crucial for environmental evaluation. Because soil pH and land use types have strong effects on the bioavailability of trace metals in soil, they were taken into account by some environmental protection agencies in making composite soil environmental quality standards (SEQSs) that contain multiple metal thresholds under different pH and land use conditions. This study proposed a method for estimating the standard-exceeding probability map of soil cadmium using a composite SEQS. The spatial variability and uncertainty of soil pH and site-specific land use type were incorporated through simulated realizations by sequential Gaussian simulation. A case study was conducted using a sample data set from a 150 km(2) area in Wuhan City and the composite SEQS for cadmium, recently set by the State Environmental Protection Administration of China. The method may be useful for evaluating the pollution risks of trace metals in soil with composite SEQSs.

  11. Comparative Degradation of a Thiazole Pollutant by an Advanced Oxidation Process and an Enzymatic Approach.

    PubMed

    Al-Maqdi, Khadega A; Hisaindee, Soleiman M; Rauf, Muhammad A; Ashraf, Syed Salman

    2017-08-24

    Organic pollutants, especially those found in water bodies, pose a direct threat to various aquatic organisms as well as humans. A variety of different remediation approaches, including chemical and biological methods, have been developed for the degradation of various organic pollutants. However, comparative mechanistic studies of pollutant degradation by these different systems are almost non-existent. In this study, the degradation of a model thiazole pollutant, thioflavin T (ThT), was carried out in the presence of either an advanced oxidation process (ultraviolet (UV) + H₂O₂) or a chloroperoxidase enzyme system (CPO + H₂O₂). The degradation was followed both spectrophotometrically and using liquid chromatography-mass spectroscopy (LC-MS), and the products formed were identified using tandem liquid chromatography-mass spectrometry-mass spectrometry (LC-MS-MS). The results show that the two remediation approaches produced different sets of intermediates, with only one common species (a demethylated form of ThT). This suggests that different degradation schemes were operating in the two systems. Interestingly, one of the major intermediates produced by the CPO + H₂O₂ system was a chlorinated form of thioflavin. Phytotoxicity studies showed that the CPO + H₂O₂-treated ThT solution was significantly (p <0.05) less toxic than the UV + H₂O₂-treated ThT solution. This is the first time that a comparative mechanistic study showing in detail the intermediates generated in chemical and biological remediation methods has been presented. Furthermore, the results show that different remediation systems have very different degradation schemes and result in products having different toxicities.

  12. Natural polymers supported copper nanoparticles for pollutants degradation

    NASA Astrophysics Data System (ADS)

    Haider, Sajjad; Kamal, Tahseen; Khan, Sher Bahadar; Omer, Muhammad; Haider, Adnan; Khan, Farman Ullah; Asiri, Abdullah M.

    2016-11-01

    In this report, chitosan (CS) was adhered on cellulose microfiber mat (CMM) to prepare CS-CMM. This was used as host for copper (Cu) nanoparticles preparation. After adsorption of Cu2+ ions from an aqueous solution of CuSO4, the metal ions entrapped in CS coating layer was treated with sodium borohydride (NaBH4) to prepare Cu nanoparticles loaded CS-CMM (Cu/CS-CMM). Fourier transform infrared spectroscopy, and X-ray diffraction confirmed the formation of Cu/CS-CMM hybrid. Scanning electron microscopy analysis was performed to reveal the morphology of the prepared catalyst. The prepared Cu/CS-CMM was employed as a catalyst for the degradation of nitro-aromatic compounds of 2-nitrophenol (2NP) and 4-nitrophenol (4NP) as well as an organic cresyl blue (CB) dye. Remarkably, the turnover frequency in the case of 2NP and 4NP using Cu/CS-CMM reaches 103.3 and 88.6 h-1, outperforming previously reported Cu nanoparticles immobilized in hydrogel-based catalytic systems. The rate constants for 2NP, 4NP and CB were 1.2 × 10-3 s-1, 2.1 × 10-3 s-1 and, 1.3 × 10-3 s-1, respectively. Besides, we discussed the separation of the catalyst from the reaction mixture and its re-usability.

  13. New Photocatalysis for Effective Degradation of Organic Pollutants in Water

    NASA Astrophysics Data System (ADS)

    Zarei Chaleshtori, M.; Saupe, G. B.; Masoud, S.

    2009-12-01

    The presence of harmful compounds in water supplies and in the discharge of wastewater from chemical industries, power plants, and agricultural sources is a topic of global concern. The processes and technologies available at the present time for the treatment of polluted water are varied that include traditional water treatment processes such as biological, thermal and chemical treatment. All these water treatment processes, have limitations of their own and none is cost effective. Advanced oxidation processes have been proposed as an alternative for the treatment of this kind of wastewater. Heterogeneous photocatalysis has recently emerged as an efficient method for purifying water. TiO2 has generally been demonstrated to be the most active semiconductor material for decontamination water. One significant factor is the cost of separation TiO2, which is generally a powder having a very small particle size from the water after treatment by either sedimentation or ultrafiltration. The new photocatalyst, HTiNbO5, has been tested to determine whether its photocatalytic efficiency is good enough for use in photocatalytic water purification since it has high surface area and relatively large particle size. The larger particle sizes of the porous materials facilitate catalyst removal from a solution, after purification has taken place. It can be separated from water easily than TiO2, a significant technical improvement that might eliminate the tedious final filtration necessary with a slurry. These materials are characterized and tested as water decontamination photocatalysts. The new catalyst exhibited excellent catalytic activity, but with a strong pH dependence on the photo efficiency. These results suggest that elimination of the ion exchange character of the catalyst may greatly improve its performance at various pHs. This new research proposes to study the effects of a topotactic dehydration reaction on these new porous material catalysts.

  14. Electrokinetic delivery of persulfate to remediate PCBs polluted soils: effect of injection spot.

    PubMed

    Fan, Guangping; Cang, Long; Fang, Guodong; Qin, Wenxiu; Ge, Liqiang; Zhou, Dongmei

    2014-12-01

    Persulfate-based in situ chemical oxidation (ISCO) is a promising technique for the remediation of organic compounds contaminated soils. Electrokinetics (EK) provides an alternative method to deliver oxidants into the target zones especially in low permeable-soil. In this study, the flexibility of delivering persulfate by EK to remediate polychlorinated biphenyls (PCBs) polluted soil was investigated. 20% (w/w) of persulfate was injected at the anode, cathode and both electrodes to examine its transport behaviors under electrical field, and the effect of field inversion process was also evaluated. The results showed that high dosage of persulfate could be delivered into S4 section (near cathode) by electroosmosis when persulfate was injected from anode, 30.8% of PCBs was removed from the soil, and the formed hydroxyl precipitation near the cathode during EK process impeded the transportation of persulfate. In contrast, only 18.9% of PCBs was removed with the injection of persulfate from cathode, although the breakthrough of persulfate into the anode reservoir was observed. These results indicated that the electroosmotic flow is more effective for the transportation of persulfate into soil. The addition of persulfate from both electrodes did not significantly facilitate the PCBs oxidation as well as the treatment of electrical field reversion, the reinforced negative depolarization function occurring in the cathode at high current consumed most of the oxidant. Furthermore, it was found that strong acid condition near the anode favored the oxidation of PCBs by persulfate and the degradation of PCBs was in consistent with the oxidation of Soil TOC in EK/persulfate system. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. DDT degradation efficiency and ecotoxicological effects of two types of nano-sized zero-valent iron (nZVI) in water and soil.

    PubMed

    El-Temsah, Yehia S; Sevcu, Alena; Bobcikova, Katerina; Cernik, Miroslav; Joner, Erik J

    2016-02-01

    Nano-scale zero-valent iron (nZVI) has been conceived for cost-efficient degradation of chlorinated pollutants in soil as an alternative to e.g permeable reactive barriers or excavation. Little is however known about its efficiency in degradation of the ubiquitous environmental pollutant DDT and its secondary effects on organisms. Here, two types of nZVI (type B made using precipitation with borohydride, and type T produced by gas phase reduction of iron oxides under H2) were compared for efficiency in degradation of DDT in water and in a historically (>45 years) contaminated soil (24 mg kg(-1) DDT). Further, the ecotoxicity of soil and water was tested on plants (barley and flax), earthworms (Eisenia fetida), ostracods (Heterocypris incongruens), and bacteria (Escherichia coli). Both types of nZVI effectively degraded DDT in water, but showed lower degradation of aged DDT in soil. Both types of nZVI had negative impact on the tested organisms, with nZVI-T giving least adverse effects. Negative effects were mostly due to oxidation of nZVI, resulting in O2 consumption and excess Fe(II) in water and soil.

  16. Influence of solubilizing agents (cyclodextrin or surfactant) on phenanthrene degradation by electro-Fenton process--study of soil washing recycling possibilities and environmental impact.

    PubMed

    Mousset, Emmanuel; Oturan, Nihal; van Hullebusch, Eric D; Guibaud, Gilles; Esposito, Giovanni; Oturan, Mehmet A

    2014-01-01

    One of the aims in soil washing treatment is to reuse the extracting agent and to remove the pollutant in the meantime. Thus, electro-Fenton (EF) degradation of synthetic soil washing solutions heavily loaded with phenanthrene was suggested for the first time. Two solubilising agents hydroxypropyl-beta-cyclodextrin (HPCD) and Tween 80(®) (TW 80) were chosen as cyclodextrin (CD) and surfactant representatives, respectively. In order to reuse HPCD and to degrade the pollutant simultaneously, the following optimal parameters were determined: [Fe(2+)] = 0.05 mM (catalyst), I = 2000 mA, and natural solution pH (around 6), without any adjustment. Only 50% of TW 80 (still higher than the critical micelle concentration (CMC)) can be reused against 90% in the case of HPCD while phenanthrene is completely degraded in the meantime, after only 180 min of treatment. This can be explained by the ternary complex formation (Fe(2+)-HPCD-organic pollutant) (equilibrium constant K = 56 mM(-1)) that allows OH to directly degrade the contaminant. This confirms that Fe(2+) plays an important role as a catalyst since it can promote formation of hydroxyl radicals near the pollutant and minimize HPCD degradation. After 2 h of treatment, HPCD/phenanthrene solution got better biodegradability (BOD5/COD = 0.1) and lower toxicity (80% inhibition of luminescence of Vibrio fischeri bacteria) than TW 80/phenanthrene (BOD5/COD = 0.08; 99% inhibition of V. fischeri bacteria). According to these data, HPCD employed in this integrated (soil washing + EF degradation) approach gave promising results in order to be reused whereas the pollutant is degraded in the meanwhile. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Sensitivity of desert cryptograms to air pollutants: soil crusts and rock lichens

    USGS Publications Warehouse

    Belnap, J.

    1991-01-01

    Parks throughout the West are being faced with increasing air pollution threats from current or proposed industries near their boundaries. For this reason, it is important to understand the effects these industries may have on desert ecosystems. Rock lichens can be excellent biomonitors, acting as early warning systems of impending damage to other components of the desert ecosystem. Cryptogamic crusts, consisting mostly of cyanobacteria and lichens, may not only be excellent bioindicators, but also are an essential part of the desert ecosystem. Their presence is critical for soil stability as well as for the contribution of nitrogen to the ecosystem in a form available to higher plants. Air pollutants, such as emissions from coal-fired power plants, may threaten the healthy functioning of these non-vascular plants. The purpose of this study is to determine if, in fact, air pollutants do have an impact on the physiological functioning of cryptogamic crusts or rock lichens in desert systems and, if so, to what extent. Some results have already been obtained. Both rock lichens and cryptogamic crusts exhibit physiological damage in the vicinity of the Navajo Generating Station in Page, Arizona. Increased electrolyte leakage and chlorophyll degradation, along with reduced nitrogen fixation, have been found. Preliminary studies comparing sensitivity between substrates indicate that crusts on limestone and sandstone substrates may be more sensitive than those on gypsum.

  18. Hydrocarbon-degrading filamentous fungi isolated from flare pit soils in northern and western Canada.

    PubMed

    April, T M; Foght, J M; Currah, R S

    2000-01-01

    Sixty-four species of filamentous fungi from five flare pits in northern and western Canada were tested for their ability to degrade crude oil using gas chromatographic analysis of residual hydrocarbons following incubation. Nine isolates were tested further using radiorespirometry to determine the extent of mineralization of model radiolabelled aliphatic and aromatic hydrocarbons dissolved in crude oil. Hydrocarbon biodegradation capability was observed in species representing six orders of the Ascomycota. Gas chromatography indicated that species capable of hydrocarbon degradation attacked compounds within the aliphatic fraction of crude oil, n-C12-n-C26; degradation of compounds within the aromatic fraction was not observed. Radiorespirometry, using n-[1-14C]hexadecane and [9-14C]phenanthrene, confirmed the gas chromatographic results and verified that aliphatic compounds were being mineralized, not simply transformed to intermediate metabolites. This study shows that filamentous fungi may play an integral role in the in situ biodegradation of aliphatic pollutants in flare pit soils.

  19. Persistence and degradation of metalaxyl, mancozeb fungicides and its metabolite ethylenethiourea in soils.

    PubMed

    Hanumantharaju, T H; Awasthi, M D

    2004-10-01

    The degradation pattern of metalaxyl, mancozeb and its metabolite ethylenethiourea (ETU) residues indicated a close correspondence to first order exponential degradation kinetics in soils. Degradation of fungicides in soils was predominantly biological as well as chemical in nature. Slower degradation ofmetalaxyl was noticed in the soils and their half-life values were higher than mancozeb and ETU as evident by wide range of half-life values from 41.24 to 165.11 days. In case of metalaxyl, Hiriyur soil was found to be superior in degrading the metalaxyl. Lower persistence of mancozeb and ETU was observed in soils resulting in rapid rate of degradation at smaller half-life values as compared to metalaxyl indicating the faster degradation of mancozeb and ETU. In mancozeb applied soils, the ETU formation was increased up to 30 days of incubation and thereafter it declined. Amongsoils, degradation of either mancozeb or ETU is not influenced by soil types. However, mancozeb persistence was higher in Hiriyur soils than Chettalli and Bangalore soils.

  20. Fertilization stimulates anaerobic fuel degradation of antarctic soils by denitrifying microorganisms.

    PubMed

    Powell, Shane M; Ferguson, Susan H; Snape, Ian; Siciliano, Steven D

    2006-03-15

    Human activities in the Antarctic have resulted in hydrocarbon contamination of these fragile polar soils. Bioremediation is one of the options for remediation of these sites. However, little is known about anaerobic hydrocarbon degradation in polar soils and the influence of bioremediation practices on these processes. Using a field trial at Old Casey Station, Antarctica, we assessed the influence of fertilization on the anaerobic degradation of a 20-year old fuel spill. Fertilization increased hydrocarbon degradation in both anaerobic and aerobic soils when compared to controls, but was of most benefit for anaerobic soils where evaporation was negligible. This increased biodegradation in the anaerobic soils corresponded with a shift in the denitrifier community composition and an increased abundance of denitrifiers and benzoyl-CoA reductase. A microcosm study using toluene and hexadecane confirmed the degradative capacity within these soils under anaerobic conditions. It was observed that fertilized anaerobic soil degraded more of this hydrocarbon spike when incubated anaerobically than when incubated aerobically. We conclude that denitrifiers are actively involved in hydrocarbon degradation in Antarctic soils and that fertilization is an effective means of stimulating their activity. Further, when communities stimulated to degrade hydrocarbons under anaerobic conditions are exposed to oxygen, hydrocarbon degradation is suppressed. The commonly accepted belief that remediation of polar soils requires aeration needs to be reevaluated in light of this new data.

  1. Influence of soil frost on the character and degradability of dissolved organic carbon in boreal forest soils

    NASA Astrophysics Data System (ADS)

    Panneer Selvam, B.; Laudon, H.; Guillemette, F.; Berggren, M.

    2016-03-01

    Recent studies suggest that increases in extent and duration of winter soil frost increases dissolved organic carbon (DOC) concentrations in boreal riparian soils and connected aquatic systems during the subsequent spring and summer. However, little is known about the impact of frost on DOC character and its degradability. We applied three experimental treatments to riparian soils in northern Sweden—shallow soil frost (insulated), deep soil frost (snow removed) and control plots—to test the effect of different soil frost regimes on the chemical characteristics and degradability of soil DOC. Soil pore water samples were analyzed using excitation-emission fluorescence (parallel factor analysis) combined with biological and photochemical degradation experiments. We found that the absolute bacterial metabolic rates were significantly lower in samples from the shallow soil frost treatments, compared with the other treatments. Explorative multivariate analyses indicate that increasing soil frost is contributing to increased protein-like fluorescence and to increased biological degradability of the DOC. Our study shows that decreases in riparian soil frost due to climate warming may not only contribute to decreased riparian DOC concentrations but also lead to shifts in the DOC composition, resulting in decreased biodegradability (yet similar photodegradability) of the DOC that is exported from riparian soils to streams.

  2. Characterizing Soil Organic Matter Degradation Levels in Permafrost-affected Soils using Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Matamala, R.; Jastrow, J. D.; Calderon, F.; Liang, C.; Miller, R. M.; Ping, C. L.; Michaelson, G. J.; Hofmann, S.

    2014-12-01

    Diffuse-reflectance Fourier-transform mid-infrared spectroscopy (MidIR) was used to (1) investigate soil quality along a latitudinal gradient of Alaskan soils, and in combination with soil incubations, (2) to assess the relative lability of soil organic matter in the active layer and upper permafrost for some of those soils. Twenty nine sites were sampled along a latitudinal gradient (78.79 N to 55.35 N deg). The sites included 8 different vegetation types (moss/lichen, non-acidic and acidic tundra, shrub areas, deciduous forests, mixed forests, coniferous forests, and grassland). At each site, soils were separated by soil horizons and analyzed for pH, cation exchange capacity (CEC), organic and inorganic C, and total N. Samples were also scanned to obtain MidIR spectra, and ratios of characteristic bands previously suggested as indicators of organic matter quality or degradation level were calculated. Principal component analysis showed that axis 1 explained 70% of the variation and was correlated with the general Organic:Mineral ratio, soil organic C, total N, and CEC, but not with vegetation type. Axis 2 explained 25% of the variation and was correlated with most of the band ratios, with negative values for the condensation index (ratio of aromatic to aliphatic organic matter) and positive values for all humification ratios (HU1: ratio of aliphatic to polysaccharides; HU2: ratio of aromatics to polysaccharides; and HU3 ratio of lignin/phenols to polysaccharides) suggesting that axis 2 variations were related to differences in level of soil organic matter degradation. Active organic, active mineral and permafrost layers from selected tundra sites were incubated for two months at -1, 1, 4, 8 and 16 ⁰C. The same band ratios were correlated with total CO2 mineralized during the incubations. Data from 4⁰C showed that the cumulative respired CO2 from the active organic layer across all sites was negatively correlated with the HU1 humification ratio, suggesting

  3. Growth response of Zea mays L. in pyrene-copper co-contaminated soil and the fate of pollutants.

    PubMed

    Lin, Qi; Shen, Kai-Li; Zhao, Hong-Mei; Li, Weng-Hong

    2008-02-11

    Phytoremediation, use of plants for remediation, is an emerging technology for treating heavy metals or a final polishing step for the high-level organic contamination, and may be suitable for remediation of heavy metal and organic co-contaminated soil. The aim of this study was to investigate the influence of co-contamination on the growth of Zea mays L. and the fate of both heavy metal and organic pollutants, using Cu and pyrene as the model pollutants. Results showed that shoot and root biomass were affected by the copper-pyrene co-contamination, although maize grown in spiked soils showed no outward signs of phytotoxicity. With the initial concentration of 50,100 and 500 mg/kg, pyrene tended to alleviate the inhibition of Cu to Z. mays L. Pyrene in both planted and non-planted soil was greatly decreased at the end of the 4-week culture, accounting for 16-18% of initial extractable concentrations in non-planted soil and 9-14% in planted soil, which indicated that the dissipation of soil pyrene was enhanced in the presence of vegetation probably due to the biodegradation and association with the soil matrix. With the increment of Cu level, residual pyrene in the planted soil tended to increase. The pyrene residual in the presence of high concentration of Cu was even higher in the planted soil than that in the non-planted soil, which suggested that the change of the microbial composition and microbial activity or the modified root physiology under Cu stress was probably unbeneficial to the dissipation of pyrene. A more thorough understanding of the mechanisms by which metals affect the dissipation of organic pollutants in the rhizosphere could provide a much better framework on which to base manipulation. Unlike pyrene, heavy metal copper cannot be degraded. Decontamination of Cu from contaminated soils in this system required the removal of Cu by plants. It was observed that the ability of Cu phytoextraction would be inhibited under co-contamination of high level

  4. Fungicide dissipation and impact on metolachlor aerobic soil degradation and soil microbial dynamics.

    PubMed

    White, Paul M; Potter, Thomas L; Culbreath, Albert K

    2010-02-15

    Pesticides are typically applied as mixtures and or sequentially to soil and plants during crop production. A common scenario is herbicide application at planting followed by sequential fungicide applications post-emergence. Fungicides depending on their spectrum of activity may alter and impact soil microbial communities. Thus there is a potential to impact soil processes responsible for herbicide degradation. This may change herbicide efficacy and environmental fate characteristics. Our study objective was to determine the effects of 4 peanut fungicides, chlorothalonil (2,4,5,6-tetrachloro-1,3-benzenedicarbonitrile), tebuconazole (alpha-[2-(4-chlorophenyl)ethyl]-alpha-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol), flutriafol (alpha-(2-fluorophenyl)-alpha-(4-fluorophenyl)-1H-1,2,4-triazole-1-ethanol), and cyproconazole (alpha-(4-chlorophenyl)-alpha-(1-cyclopropylethyl)-1H-1,2,4-triazole-1-ethanol) on the dissipation kinetics of the herbicide, metolachlor (2-chloro-N-(6-ethyl-o-tolyl)-N-[(1RS)-2-methoxy-1-methylethyl]acetamide), and on the soil microbial community. This was done through laboratory incubation of field treated soil. Chlorothalonil significantly reduced metolachlor soil dissipation as compared to the non-treated control or soil treated with the other fungicides. Metolachlor DT(50) was 99 days for chlorothalonil-treated soil and 56, 45, 53, and 46 days for control, tebuconazole, flutriafol, and cyproconazole-treated soils, respectively. Significant reductions in predominant metolachlor metabolites, metolachlor ethane sulfonic acid (MESA) and metolachlor oxanilic acid (MOA), produced by oxidation of glutathione-metolachlor conjugates were also observed in chlorothalonil-treated soil. This suggested that the fungicide impacted soil glutathione-S-transferase (GST) activity. Fungicide DT(50) was 27-80 days but impacts on the soil microbial community as indicated by lipid biomarker analysis were minimal. Overall study results indicated that

  5. Heavy Metals Phytoextraction from the Polluted Soils of Zakamensk (Russia)

    NASA Astrophysics Data System (ADS)

    Ubugunov, V.; Dorzhonova, V.; Ubugunov, L.

    2012-04-01

    the landscape - Modonkul river flood plain, were transferred by its waters and redeposited in an estuary, forming a cone of carrying out with capacity of up to 2 meters or more. The presence of large number of private houses with garden plots, in which the population grew potatoes, vegetables and fruit-berry trees cultures for food purposes, is the feature of many Siberian towns, including Zakamensk. The biogeochemical assessment of the town territory current status has shown a high level of contamination of soils and plants by heavy metals that poses a threat to the health of townsmen. In this connection search of effective ways of clearing up of the polluted soils by phytoextraction and selection of plants, capable to extract high quantities of heavy metals from soil in concrete ecological conditions, is actual. For this purpose we had been made experiments with 8 species of plants. Modeling of various conditions of pollution carried out by addition of following quantities of TS (%): 0; 25; 33; 50; 67; 75 and 100. In the report results of the experiments and the recommendations on using of plants as extractors on soils polluted by technogenic sand will be presented.

  6. Effect of long-term zinc pollution on soil microbial community resistance to repeated contamination.

    PubMed

    Klimek, Beata

    2012-04-01

    The aim of the study was to compare the effects of stress (contamination trials) on the microorganisms in zinc-polluted soil (5,018 mg Zn kg(-1) soil dry weight) and unpolluted soil (141 mg Zn kg(-1) soil dw), measured as soil respiration rate. In the laboratory, soils were subjected to copper contamination (0, 500, 1,500 and 4,500 mg kg(-1) soil dw), and then a bactericide (oxytetracycline) combined with a fungicide (captan) along with glucose (10 mg g(-1) soil dw each) were added. There was a highly significant effect of soil type, copper treatment and oxytetracycline/captan treatment. The initial respiration rate of chronically zinc-polluted soil was higher than that of unpolluted soil, but in the copper treatment it showed a greater decline. Microorganisms in copper-treated soil were more susceptible to oxytetracycline/captan contamination. After the successive soil contamination trials the decline of soil respiration was greater in zinc-polluted soil than in unpolluted soil.

  7. Degradation kinetics of forchlorfenuron in typical grapevine soils of India and its influence on specific soil enzyme activities.

    PubMed

    Banerjee, Kaushik; Dasgupta, Soma; Oulkar, Dasharath P; Patil, Sangram H; Adsule, Pandurang G

    2008-05-01

    The rate of degradation of forchlorfenuron, a cytokinin-based plant growth regulator (PGR) was explored in typical grapevine soils of India with simultaneous evaluation of its effect on biochemical attributes of the test soils in terms of the activities of specific soil microbial enzymes. In all the test soils, namely clay, sandy-loam and silty-clay, the dissipation rate was faster at the beginning, which slowed down with time, indicating a non-linear pattern of degradation. Degradation in soils could best be explained by two-compartment 1st+1st order kinetics with half-life ranging between 4-10 days. The results suggest that organic matter might be playing a major role in influencing the rate of degradation of forchlorfenuron in soil. The rate of degradation in sandy-loam soil was fastest followed by clay and silty-clay soils, respectively. Comparison of the rate of degradation in natural against sterilized soils suggests that microbial degradation might be the major pathway of residue dissipation. Changes in soil enzyme activities as a consequence of forchlorfenuron treatment were studied for extra-cellular enzymes namely acid phosphatase, alkaline phosphatase and beta -glucosidase and intracellular enzyme-dehydrogenase. Although small changes in enzyme activities were observed, forchlorfenuron did not have any significant deleterious effect on the enzymatic activity of the test soils. Simple correlation studies between degradation percentage and individual enzyme activities did not establish any significant relationships. The pattern and change of enzyme activity was primarily the effect of the incubation period rather than the effect of forchlorfenuron itself.

  8. Degradation of organic pollutants in a photoelectrocatalytic system enhanced by a microbial fuel cell.

    PubMed

    Yuan, Shi-Jie; Sheng, Guo-Ping; Li, Wen-Wei; Lin, Zhi-Qi; Zeng, Raymond J; Tong, Zhong-Hua; Yu, Han-Qing

    2010-07-15

    Photocatalytic oxidation mediated by TiO(2) is a promising oxidation process for degradation of organic pollutants, but suffers from the decreased photocatalytic efficiency attributed to the recombination of photogenerated electrons and holes. Thus, a cost-effective supply of external electrons is an effective way to elevate the photocatalytic efficiency. Here we report a novel bioelectrochemical system to effectively reduce p-nitrophenol as a model organic pollutant with utilization of the energy derived from a microbial fuel cell. In such a system, there is a synergetic effect between the electrochemical and photocatalytic oxidation processes. Kinetic analysis shows that the system exhibits a more rapid p-nitrophenol degradation at a rate two times the sum of rates by the individual photocatalytic and electrochemical methods. The system performance is influenced by both external resistor and electrolyte concentration. Either a lower external resistor or a lower electrolyte concentration results in a higher p-nitrophenol degradation rate. This system has a potential for the effective degradation of refractory organic pollutants and provides a new way for utilization of the energy generated from conversion of organic wastes by microbial fuel cells.

  9. Microwave-induced carbon nanotubes catalytic degradation of organic pollutants in aqueous solution.

    PubMed

    Chen, Jing; Xue, Shuang; Song, Youtao; Shen, Manli; Zhang, Zhaohong; Yuan, Tianxin; Tian, Fangyuan; Dionysiou, Dionysios D

    2016-06-05

    In this study, a new catalytic degradation technology using microwave induced carbon nanotubes (MW/CNTs) was proposed and applied in the treatment of organic pollutants in aqueous solution. The catalytic activity of three CNTs of 10-20nm, 20-40nm, and 40-60nm diameters were compared. The results showed that organic pollutants such as methyl orange (MO), methyl parathion (MP), sodium dodecyl benzene sulfonate (SDBS), bisphenol A (BPA), and methylene blue (MB) in aqueous solution could be degraded effectively and rapidly in MW/CNTs system. CNTs with diameter of 10-20nm exhibited the highest catalytic activity of the three CNTs under MW irradiation. Further, complete degradation was obtained using 10-20nm CNTs within 7.0min irradiation when 25mL MO solution (25mg/L), 1.2g/L catalyst dose, 450W, 2450MHz, and pH=6.0 were applied. The rate constants (k) for the degradation of SDBS, MB, MP, MO and BPA using 10-20nm CNTs/MW system were 0.726, 0.679, 0.463, 0.334 and 0.168min(-1), respectively. Therefore, this technology may have potential application for the treatment of targeted organic pollutants in wastewaters.

  10. Microwaves and their coupling to advanced oxidation processes: enhanced performance in pollutants degradation.

    PubMed

    Nascimento, Ulisses M; Azevedo, Eduardo B

    2013-01-01

    This review assesses microwaves (MW) coupled to advanced oxidation processes (AOPs) for pollutants degradation, as well as the basic theory and mechanisms of MW dielectric heating. We addressed the following couplings: MW/H2O2, MW/UV/H2O2, MW/Fenton, MW/US, and MW/UV/TiO2, as well as few studies that tested alternative oxidants and catalysts. Microwave Discharge Electrodeless Lamps (MDELs) are being extensively used with great advantages over ballasts. In their degradation studies, researchers generally employed domestic ovens with minor adaptations. Non-thermal effects and synergies between UV and MW radiation play an important role in the processes. Published papers so far report degradation enhancements between 30 and 1,300%. Unfortunately, how microwaves enhance pollutants is still obscure and real wastewaters scarcely studied. Based on the results surveyed in the literature, MW/AOPs are promising alternatives for treating/remediating environmental pollutants, whenever one considers high degradation yields, short reaction times, and small costs.

  11. Soil pollution by a pyrite mine spill in Spain: evolution in time.

    PubMed

    Aguilar, J; Dorronsoro, C; Fernández, E; Fernández, J; García, I; Martín, F; Simón, M

    2004-12-01

    Soil pollution was studied after the spill of the Aznalcóllar pyrite mine between 1998 and 2001, analyzing As, Zn, Cd, Cu and Pb both in total concentrations as well as in soluble and bioavailable forms. The main remediation measures were: clean-up of the tailings and polluted soils, plus application of amendment materials (liming). The results indicate that, after three years, 50-70% of the acidic soils and 25-30% of the basic soils are still highly polluted in total arsenic. The limit of 0.04 mg kg(-1) for water-soluble arsenic is exceeded in 15-20% of all soils. The EDTA-extractable arsenic (bioavailable) exceeds the limit of 2 mg kg(-1) only in the acidic sectors. After clean-up, the homogenization of the upper 20-25 cm of the soils appears to be the most recommended measure in the reduction of pollution.

  12. Soil features in rookeries of Antarctic penguins reveal sea to land biotransport of chemical pollutants.

    PubMed

    Santamans, Anna C; Boluda, Rafael; Picazo, Antonio; Gil, Carlos; Ramos-Miras, Joaquín; Tejedo, Pablo; Pertierra, Luis R; Benayas, Javier; Camacho, Antonio

    2017-01-01

    The main soil physical-chemical features, the concentrations of a set of pollutants, and the soil microbiota linked to penguin rookeries have been studied in 10 selected sites located at the South Shetland Islands and the Antarctic Peninsula (Maritime Antarctica). This study aims to test the hypothesis that biotransport by penguins increases the concentration of pollutants, especially heavy metals, in Antarctic soils, and alters its microbiota. Our results show that penguins do transport certain chemical elements and thus cause accumulation in land areas through their excreta. Overall, a higher penguin activity is associated with higher organic carbon content and with higher concentrations of certain pollutants in soils, especially cadmium, cooper and arsenic, as well as zinc and selenium. In contrast, in soils that are less affected by penguins' faecal depositions, the concentrations of elements of geochemical origin, such as iron and cobalt, increase their relative weighted contribution, whereas the above-mentioned pollutants maintain very low levels. The concentrations of pollutants are far higher in those penguin rookeries that are more exposed to ship traffic. In addition, the soil microbiota of penguin-influenced soils was studied by molecular methods. Heavily penguin-affected soils have a massive presence of enteric bacteria, whose relative dominance can be taken as an indicator of penguin influence. Faecal bacteria are present in addition to typical soil taxa, the former becoming dominant in the microbiota of penguin-affected soils, whereas typical soil bacteria, such as Actinomycetales, co-dominate the microbiota of less affected soils. Results indicate that the continuous supply by penguin faeces, and not the selectivity by increased pollutant concentrations is the main factor shaping the soil bacterial community. Overall, massive penguin influence results in increased concentrations of certain pollutants and in a strong change in taxa dominance in the

  13. Soil features in rookeries of Antarctic penguins reveal sea to land biotransport of chemical pollutants

    PubMed Central

    Santamans, Anna C.; Boluda, Rafael; Picazo, Antonio; Gil, Carlos; Ramos-Miras, Joaquín; Tejedo, Pablo; Pertierra, Luis R.; Benayas, Javier

    2017-01-01

    The main soil physical-chemical features, the concentrations of a set of pollutants, and the soil microbiota linked to penguin rookeries have been studied in 10 selected sites located at the South Shetland Islands and the Antarctic Peninsula (Maritime Antarctica). This study aims to test the hypothesis that biotransport by penguins increases the concentration of pollutants, especially heavy metals, in Antarctic soils, and alters its microbiota. Our results show that penguins do transport certain chemical elements and thus cause accumulation in land areas through their excreta. Overall, a higher penguin activity is associated with higher organic carbon content and with higher concentrations of certain pollutants in soils, especially cadmium, cooper and arsenic, as well as zinc and selenium. In contrast, in soils that are less affected by penguins’ faecal depositions, the concentrations of elements of geochemical origin, such as iron and cobalt, increase their relative weighted contribution, whereas the above-mentioned pollutants maintain very low levels. The concentrations of pollutants are far higher in those penguin rookeries that are more exposed to ship traffic. In addition, the soil microbiota of penguin-influenced soils was studied by molecular methods. Heavily penguin-affected soils have a massive presence of enteric bacteria, whose relative dominance can be taken as an indicator of penguin influence. Faecal bacteria are present in addition to typical soil taxa, the former becoming dominant in the microbiota of penguin-affected soils, whereas typical soil bacteria, such as Actinomycetales, co-dominate the microbiota of less affected soils. Results indicate that the continuous supply by penguin faeces, and not the selectivity by increased pollutant concentrations is the main factor shaping the soil bacterial community. Overall, massive penguin influence results in increased concentrations of certain pollutants and in a strong change in taxa dominance in the

  14. Transcriptional profiling of Gram-positive Arthrobacter in the phyllosphere: induction of pollutant degradation genes by natural plant phenolic compounds.

    PubMed

    Scheublin, Tanja R; Deusch, Simon; Moreno-Forero, Silvia K; Müller, Jochen A; van der Meer, Jan Roelof; Leveau, Johan H J

    2014-07-01

    Arthrobacter chlorophenolicus A6 is a Gram-positive, 4-chlorophenol-degrading soil bacterium that was recently shown to be an effective colonizer of plant leaf surfaces. The genetic basis for this phyllosphere competency is unknown. In this paper, we describe the genome-wide expression profile of A.chlorophenolicus on leaves of common bean (Phaseolus vulgaris) compared with growth on agar surfaces. In phyllosphere-grown cells, we found elevated expression of several genes known to contribute to epiphytic fitness, for example those involved in nutrient acquisition, attachment, stress response and horizontal gene transfer. A surprising result was the leaf-induced expression of a subset of the so-called cph genes for the degradation of 4-chlorophenol. This subset encodes the conversion of the phenolic compound hydroquinone to 3-oxoadipate, and was shown to be induced not only by 4-chlorophenol but also hydroquinone, its glycosylated derivative arbutin, and phenol. Small amounts of hydroquinone, but not arbutin or phenol, were detected in leaf surface washes of P.vulgaris by gas chromatography-mass spectrometry. Our findings illustrate the utility of genomics approaches for exploration and improved understanding of a microbial habitat. Also, they highlight the potential for phyllosphere-based priming of bacteria to stimulate pollutant degradation, which holds promise for the application of phylloremediation.

  15. Contribution to the study of pollution of soil and water in Oued El Maleh area (Mohammedia, Morocco)

    NASA Astrophysics Data System (ADS)

    El hajjaji, Souad; Dahchour, Abdelmalek; Belhsaien, Kamal; Zouahri, Abdelmjid; Moussadek, Rachid; Douaik, Ahmed

    2016-04-01

    In Morocco, diffuse ground and surface water pollution in irrigated areas has caused an increase in the risk of water and soil quality deterioration. This has generated a health and environmental risks. The present study was carried out in the Oued El Maleh region located 65 Km to the south of Rabat on the Moroccan Atlantic coast. It covers a surface area of 310 km2 where agriculture constitutes the main activity of the population. This region is considered as a very important agricultural area, known nationally for its high potential for market gardening. This intensification has been accompanied by an excessive use of agrochemical inputs and poor control of irrigation and drainage. Consequently, salinization phenomena and deterioration of soil structure as well as water are about to create an alarming situation. In order to assess the state of pollution of waters and soil in the region, our study focuses on the determination of physicochemical parameters for the quality of water and soil. The obtained results from sampled wells and surface water show relatively higher values of nitrate and conductivity exceeding Moroccan national standards and revealing net degradation of water quality; therefore the water can be considered not suitable for human consumption and can induce a degradation of soil. The results of the studied soil show that the pH of these soils is weakly to moderately basic; they are usually non-saline with organic matter content moderately filled. Moreover, very high concentrations of nutrients (potassium, phosphorus and nitrogen) were recorded, highlighting poor management fertilizing vegetable crops in the region of Oued El Maleh.

  16. Bioremediation of polluted soil through the combined application of plants, earthworms and organic matter.

    PubMed

    Macci, Cristina; Doni, Serena; Peruzzi, Eleonora; Ceccanti, Brunello; Masciandaro, Grazia

    2012-10-26

    Two plant species (Paulownia tomentosa and Cytisus scoparius), earthworms (Eisenia fetida), and organic matter (horse manure) were used as an ecological approach to bioremediate a soil historically contaminated by heavy metals and hydrocarbons. The experiment was carried out for six months at a mesoscale level using pots containing 90 kg of polluted soil. Three different treatments were performed for each plant: (i) untreated planted soil as a control (C); (ii) planted soil + horse manure (20:1 w/w) (M); (iii) planted soil + horse manure + 15 earthworms (ME). Both the plant species were able to grow in the polluted soil and to improve the soil's bio-chemical conditions, especially when organic matter and earthworms were applied. By comparing the two plant species, few significant differences were observed in the soil characteristics; Cytisus scoparius improved soil nutrient content more than Paulownia tomentosa, which instead stimulated more soil microbial metabolism. Regarding the pollutants, Paulownia tomentosa was more efficient in reducing the heavy metal (Pb, Cr, Cd, Zn, Cu, Ni) content, while earthworms were particularly able to stimulate the processes involved in the decontamination of organic pollutants (hydrocarbons). This ecological approach, validated at a mesoscale level, has recently been transferred to a real scale situation to carry out the bioremediation of polluted soil in San Giuliano Terme Municipality (Pisa, Italy).

  17. Nitrification and urea hydrolysis in deciduous woodland soils from a site exposed to heavy atmospheric pollution.

    PubMed

    Nevell, W; Wainwright, M

    1987-01-01

    Laboratory studies of nitrification and urea hydrolysis were performed using soils obtained from sites exposed to pollution from a coking works and from a relatively unpolluted site. No net production of nitrate occurred in either soil when amended with ammonium sulphate alone, or together with CaCO(3) at 0.05% w/w. However, nitrate accumulated in both soils when 5% w/w CaCO(3) was added, with this amount of lime increasing the pH of both soils from around pH4 to pH7. Under these conditions, nitrification in the polluted soil occurred at about half the rate found in the relatively unpolluted soil. Urea hydrolysis occurred at a similar rate in both soils and was not impaired by exposure to coking pollution. Little nitrification of the ammonium liberated by urea hydrolysis occurred in either soil, however, presumably because, although the soil pH increased due to urea hydrolysis, it did not become sufficiently alkaline to support rapid nitrification. The relatively unpolluted soil used here was obtained from an area away from the coking works, but was exposed to generalised atmospheric pollution (wet and dry deposited acidity, greater than 1.0 and 2.4 kg H(+) ha(-1) yr(-1), respectively). Nitrification and urea hydrolysis occurred in these soils, so these processes were not inhibited by exposure to these relatively high background levels of air pollution.

  18. Decision support tool for soil sampling of heterogeneous pesticide (chlordecone) pollution.

    PubMed

    Clostre, Florence; Lesueur-Jannoyer, Magalie; Achard, Raphaël; Letourmy, Philippe; Cabidoche, Yves-Marie; Cattan, Philippe

    2014-02-01

    When field pollution is heterogeneous due to localized pesticide application, as is the case of chlordecone (CLD), the mean level of pollution is difficult to assess. Our objective was to design a decision support tool to optimize soil sampling. We analyzed the CLD heterogeneity of soil content at 0-30- and 30-60-cm depth. This was done within and between nine plots (0.4 to 1.8 ha) on andosol and ferralsol. We determined that 20 pooled subsamples per plot were a satisfactory compromise with respect to both cost and accuracy. Globally, CLD content was greater for andosols and the upper soil horizon (0-30 cm). Soil organic carbon cannot account for CLD intra-field variability. Cropping systems and tillage practices influence the CLD content and distribution; that is CLD pollution was higher under intensive banana cropping systems and, while upper soil horizon was more polluted than the lower one with shallow tillage (<40 cm), deeper tillage led to a homogenization and a dilution of the pollution in the soil profile. The decision tool we proposed compiles and organizes these results to better assess CLD soil pollution in terms of sampling depth, distance, and unit at field scale. It accounts for sampling objectives, farming practices (cropping system, tillage), type of soil, and topographical characteristics (slope) to design a relevant sampling plan. This decision support tool is also adaptable to other types of heterogeneous agricultural pollution at field level.

  19. [Assessment of soil degradation in regions of nuclear power explosions at Semipalatinsk Nuclear Test Site].

    PubMed

    Evseeva, T I; Geras'kin, S A; Maĭstrenko, T A; Belykh, E S

    2011-01-01

    Degree of the soil cover degradation at the "Balapan" and "Experimental field" test sites was assessed based on Allium-test of soil toxicity results and international guidelines on radioactive restriction of solid materials (IAEA, 2004) and environment (Smith, 2005). Soil cover degradation maps of large-scale (1 : 25000) were made. The main part of the area mapped belongs to high-contaminated toxic degraded soil. A relationship between the soil toxicity and the total radionuclide activity concentrations was found to be described by power functions. When the calculated value (equal to 413-415 Bq/kg of air dry soil) increases, the soil becomes toxic for plants. This value is 7.8 times higher than the maximal value for background territories (53 Bq/kg) surrounding SNTS. Russian sanitary and hygienic guidelines (Radiation safety norms, 2009; Sanitary regulations of radioactive waste management, 2003) underestimate the degree of soil radioactive contamination for plants.

  20. Effects of bacterial inoculation and nonionic surfactants on degradation of polycyclic aromatic hydrocarbons in soil

    SciTech Connect

    Madsen, T.; Kristensen, P.

    1997-04-01

    The aim of the study was to examine the effects of introduced bacteria and nonionic surfactants on the degradation of polycyclic aromatic hydrocarbons (PAHs) in soil. Mineralization experiments were conducted with freshly added [{sup 14}C]phenanthrene or [{sup 14}]pyrene, whereas other experiments focused on the degradation of selected PAHs present in a coal tar-contaminated soil. Inoculation of soil samples with phenanthrene-utilizing bacteria stimulated the mineralization of [{sup 14}]phenanthrene. This effect, however, was most notable in soil with a low indigenous potential for PAH degradation, and a large inoculum was apparently required to establish phenanthrene mineralization in the soil. Addition of alcohol ethoxylate and glycoside surfactants to soil samples enhanced the mineralization of [{sup 14}]phenanthrene and [{sup 14}]pyrene. The nonionic surfactants also enhanced the degradation of contaminant PAHs that were present in the soil coal tar. As an example, pyrene, benzo[b,j,k]fluoranthene, and benzo[a]pyrene were resistant to degradation in the absence of surfactants, whereas significant degradation of these PAHs was observed when surfactants were added. The surfactant-related enhancement of the degradation of PAH contaminants was less convincing when a rapidly degradable glycoside surfactant was used. This suggests that surfactants that are mineralized at moderate rates may be more applicable for increasing the availability of PAHs in soil.

  1. Degradation of racemic and enantiopure metalaxyl in tropical and temperate soils.

    PubMed

    Monkiedje, Adolphe; Spiteller, Michael; Bester, Kai

    2003-02-15

    The degradation of the racemic mixture and the enantiomers of metalaxyl in typical soils from Germany and Cameroon has been studied. Formulated and unformulated R-metalaxyl were studied as well as racemic (rac) metalaxyl in controlled incubation experiments. The kinetics of the degradation or transformation were determined by means of reversed phase HPLC, while the enantiomeric ratios were measured by HPLC with a chiral Whelk O1 column. The degradation followed first-order kinetics (R2 > or = 0.96). Higher metalaxyl acid metabolite concentrations were found in German soil than in Cameroonian soil. The enantiomers of the fungicide each had different degradation rates in both soils, with half-lives ranging from 17 to 38 days. All forms of metalaxyl had lower degradation rates in the Cameroonian soil than in the German soil. The degradation. of the R-enantiomer was much faster than the S-enantiomer in the German soil and slower than the S-enantiomer in the Cameroonian soil suggesting that different microbial populations, which may be using different enzymes, have different degradation preferences. The results for the major differences in the degradation of the enantiomers may have some implication for the frequency of use as well as the environmental assessment for chiral pesticides.

  2. An improved method for determination of fumigant degradation half-life in soil

    USDA-ARS?s Scientific Manuscript database

    Using the current approach, measurement of fumigant degradation half-lives under realistic soil conditions is problematic due to the large headspace that is necessary above the soil during incubation. This results in a poor degree of contact between the fumigant and the soil’s degrading surfaces; di...

  3. Biodegradation Ability and Catabolic Genes of Petroleum-Degrading Sphingomonas koreensis Strain ASU-06 Isolated from Egyptian Oily Soil

    PubMed Central

    Mostafa, Yasser M.; Shoreit, Ahmed

    2014-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are serious pollutants and health hazards. In this study, 15 PAHs-degrading bacteria were isolated from Egyptian oily soil. Among them, one Gram-negative strain (ASU-06) was selected and biodegradation ability and initial catabolic genes of petroleum compounds were investigated. Comparison of 16S rRNA gene sequence of strain ASU-06 to published sequences in GenBank database as well as phylogenetic analysis identified ASU-06 as Sphingomonas koreensis. Strain ASU-06 degraded 100, 99, 98, and 92.7% of 100 mg/L naphthalene, phenanthrene, anthracene, and pyrene within 15 days, respectively. When these PAHs present in a mixed form, the enhancement phenomenon appeared, particularly in the degradation of pyrene, whereas the degradation rate was 98.6% within the period. This is the first report showing the degradation of different PAHs by this species. PCR experiments with specific primers for catabolic genes alkB, alkB1, nahAc, C12O, and C23O suggested that ASU-06 might possess genes for aliphatic and PAHs degradation, while PAH-RHDαGP gene was not detected. Production of biosurfactants and increasing cell-surface hydrophobicity were investigated. GC/MS analysis of intermediate metabolites of studied PAHs concluded that this strain utilized these compounds via two main pathways, and phthalate was the major constant product that appeared in each day of the degradation period. PMID:25177681

  4. Combined use of alkane-degrading and plant growth-promoting bacteria enhanced phytoremediation of diesel contaminated soil.

    PubMed

    Tara, Nain; Afzal, Muhammad; Ansari, Tariq M; Tahseen, Razia; Iqbal, Samina; Khan, Qaiser M

    2014-01-01

    Inoculation of plants with pollutant-degrading and plant growth-promoting microorganisms is a simple strategy to enhance phytoremediation activity. The objective of this study was to determine the effect of inoculation of different bacterial strains, possessing alkane-degradation and 1-amino-cyclopropane-1 -carboxylic acid (ACC) deaminase activity, on plant growth and phytoremediation activity. Carpet grass (Axonopus affinis) was planted in soil spiked with diesel (1% w/w) for 90 days and inoculated with different bacterial strains, Pseudomonas sp. ITRH25, Pantoea sp. BTRH79 and Burkholderia sp. PsJN, individually and in combination. Generally, bacterial application increased total numbers of culturable hydrocarbon-degrading bacteria in the rhizosphere ofcarpet grass, plant biomass production, hydrocarbon degradation and reduced genotoxicity. Bacterial strains possessing different beneficial traits affect plant growth and phytoremediation activity in different ways. Maximum bacterial population, plant biomass production and hydrocarbon degradation were achieved when carpet grass was inoculated with a consortium of three strains. Enhanced plant biomass production and hydrocarbon degradation were associated with increased numbers of culturable hydrocarbon-degrading bacteria in the rhizosphere of carpet grass. The present study revealed that the combined use of different bacterial strains, exhibiting different beneficial traits, is a highly effective strategy to improve plant growth and phytoremediation activity.

  5. Biodegradation ability and catabolic genes of petroleum-degrading Sphingomonas koreensis strain ASU-06 isolated from Egyptian oily soil.

    PubMed

    Hesham, Abd El-Latif; Mawad, Asmaa M M; Mostafa, Yasser M; Shoreit, Ahmed

    2014-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are serious pollutants and health hazards. In this study, 15 PAHs-degrading bacteria were isolated from Egyptian oily soil. Among them, one Gram-negative strain (ASU-06) was selected and biodegradation ability and initial catabolic genes of petroleum compounds were investigated. Comparison of 16S rRNA gene sequence of strain ASU-06 to published sequences in GenBank database as well as phylogenetic analysis identified ASU-06 as Sphingomonas koreensis. Strain ASU-06 degraded 100, 99, 98, and 92.7% of 100 mg/L naphthalene, phenanthrene, anthracene, and pyrene within 15 days, respectively. When these PAHs present in a mixed form, the enhancement phenomenon appeared, particularly in the degradation of pyrene, whereas the degradation rate was 98.6% within the period. This is the first report showing the degradation of different PAHs by this species. PCR experiments with specific primers for catabolic genes alkB, alkB1, nahAc, C12O, and C23O suggested that ASU-06 might possess genes for aliphatic and PAHs degradation, while PAH-RHDαGP gene was not detected. Production of biosurfactants and increasing cell-surface hydrophobicity were investigated. GC/MS analysis of intermediate metabolites of studied PAHs concluded that this strain utilized these compounds via two main pathways, and phthalate was the major constant product that appeared in each day of the degradation period.

  6. Soil fertility and plant diversity enhance microbial performance in metal-polluted soils.

    PubMed

    Stefanowicz, Anna M; Kapusta, Paweł; Szarek-Łukaszewska, Grażyna; Grodzińska, Krystyna; Niklińska, Maria; Vogt, Rolf D

    2012-11-15

    This study examined the effects of soil physicochemical properties (including heavy metal pollution) and vegetation parameters on soil basal respiration, microbial biomass, and the activity and functional richness of culturable soil bacteria and fungi. In a zinc and lead mining area (S Poland), 49 sites were selected to represent all common plant communities and comprise the area's diverse soil types. Numerous variables describing habitat properties were reduced by PCA to 7 independent factors, mainly representing subsoil type (metal-rich mining waste vs. sand), soil fertility (exchangeable Ca, Mg and K, total C and N, organic C), plant species richness, phosphorus content, water-soluble heavy metals (Zn, Cd and Pb), clay content and plant functional diversity (based on graminoids, legumes and non-leguminous forbs). Multiple regression analysis including these factors explained much of the variation in most microbial parameters; in the case of microbial respiration and biomass, it was 86% and 71%, respectively. The activity of soil microbes was positively affected mainly by soil fertility and, apparently, by the presence of mining waste in the subsoil. The mining waste contained vast amounts of trace metals (total Zn, Cd and Pb), but it promoted microbial performance due to its inherently high content of macronutrients (total Ca, Mg, K and C). Plant species richness had a relatively strong positive effect on all microbial parameters, except for the fungal component. In contrast, plant functional diversity was practically negligible in its effect on microbes. Other explanatory variables had only a minor positive effect (clay content) or no significant influence (phosphorus content) on microbial communities. The main conclusion from this study is that high nutrient availability and plant species richness positively affected the soil microbes and that this apparently counteracted the toxic effects of metal contamination. Copyright © 2012 Elsevier B.V. All rights

  7. Natural attenuation of zinc pollution in smelter-affected soil.

    PubMed

    Vespa, M; Lanson, M; Manceau, A

    2010-10-15

    Previous synchrotron X-ray microprobe measurements of Zn speciation in contaminated and uncontaminated soils have identified phyllosilicate as the main sequestration phase. The emphasis now is focused on comparing the nature and properties of neoformed and geogenic phyllosilicate species to understand natural attenuation processes. Refined structural characterization of the two types of Zn-containing phyllosilicate in slightly basic smelter-affected agricultural soils were obtained using a so far unprecedented combination of X-ray microscopic techniques, including fluorescence (μ-XRF), absorption (μ-EXAFS), and diffraction (μ-XRD), and X-ray bulk-sensitive techniques, including powder and polarized EXAFS spectroscopy. The unpolluted and polluted species are both dioctahedral smectites, but the first which contains minor Zn (ca. 150 mg/kg) is aluminous and Fe-free, and the second, which contains several hundreds to a few thousands mg/kg Zn depending on the distance to the smelter and wind direction, is ferruginous with an average Fe/Al atomic ratio of 1.1 ± 0.5. The Zn(2+) and Fe(3+) in the neoformed smectite are derived from the weathering of ZnS, ZnO, FeS(2), and ZnFe(2)O(4) particles from the smelter. These cations diffuse away from their particulate mineral sources and coprecipitate with Al and Si in the soil clay matrix. Zinc sequestration in the octahedral sheet of dioctahedral smectite is potentially irreversible, because this type of phyllosilicate is stable over a large pH range, and the neoformed species is analogous to the native species which formed over time during pedogenesis.

  8. Sorption and degradation of four nitroaromatic herbicides in mono and multi-solute saturated/unsaturated soil batch systems

    NASA Astrophysics Data System (ADS)

    Martins, Jean M.; Mermoud, André

    1998-09-01

    This paper presents a study on sorption and degradation processes involved in the fate of nitroaromatic herbicides in an alluvial sandy loam. Particular attention was given to a competitive sorption process and its impact on herbicide biodegradation through bioavailability modification. The main question addressed was the occurrence of antagonistic or synergistic effects in herbicide mixtures. Approaching the problem by using a herbicide combination, it was demonstrated that the more soluble herbicides strongly decreased the sorption of the more hydrophobic ones on the soil organic fraction. Conversely, ionic strength was shown to increase sorption levels dramatically. These results prove that soil solution chemistry is a relevant factor to be taken into account in pesticide behaviour studies. Herbicide biodegradation was studied with the same approach, and the results revealed that degradation of a particular dinitrophenol is affected by the presence of similar molecules. In well-dispersed soil suspensions where herbicide/micro-organism contact is optimal, toxicity was shown to increase herbicide persistence and to be the controlling factor of biodegradation. Conversely, persistence in repacked unsaturated soil batches was strongly decreased in both mono and multi-solute systems. In such solid batches, the soil structure imposed mass transfer kinetics which modify micro-organism/herbicide contact and decreased toxicity effects. Furthermore, the competitive sorption observed in multi-solute systems was supposed to be responsible for the observed increase of herbicide biodegradation presumably by keeping molecules bioavailable for microbial attack. These results support the assumption that soils are divided into two compartments presenting different capacities in regard to chemical sorption and biodegradation, which could be a basis for explaining chemical aging in soil. This study providing new information on physico-chemical control of pollutant biodegradation in

  9. Degradation of vanillin in soil-clay mixtures treated with simulated acid rain

    SciTech Connect

    Bewley, R.J.F.; Stotzky, G.

    1984-06-01

    Significant vanillin degradation occurred only in soil amended with 9% montmorillonite and not in soil amended with 9% kaolinite or in soil without addition of clay minerals. Progressively decreasing amounts of vanillin were mineralized in the montmorillonite-amended soil with increasing acidification with H/sub 2/SO/sub 4/, and complete inhibition of mineralization occurred at a soil pH of 1.6. 16 references, 1 table.

  10. Bacteria Associated to Plants Naturally Selected in a Historical PCB Polluted Soil Show Potential to Sustain Natural Attenuation

    PubMed Central

    Vergani, Lorenzo; Mapelli, Francesca; Marasco, Ramona; Crotti, Elena; Fusi, Marco; Di Guardo, Antonio; Armiraglio, Stefano; Daffonchio, Daniele; Borin, Sara

    2017-01-01

    The exploitation of the association between plants and microorganisms is a promising approach able to boost natural attenuation processes for soil clean-up in vast polluted areas characterized by mixed chemical contamination. We aimed to explore the selection of root-associated bacterial communities driven by different plant species spontaneously established in abandoned agricultural soils within a historical polluted site in north Italy. The site is highly contaminated by chlorinated persistent organic pollutants, mainly constituted by polychlorobiphenyls (PCBs), together with heavy metals and metalloids, in variable concentrations and uneven distribution. The overall structure of the non-vegetated and root-associated soil fractions bacterial communities was described by high-throughput sequencing of the 16S rRNA gene, and a collection of 165 rhizobacterial isolates able to use biphenyl as unique carbon source was assayed for plant growth promotion (PGP) traits and bioremediation potential. The results showed that the recruitment of specific bacterial communities in the root-associated soil fractions was driven by both soil fractions and plant species, explaining 21 and 18% of the total bacterial microbiome variation, respectively. PCR-based detection in the soil metagenome of bacterial bphA gene, encoding for the biphenyl dioxygenase α subunit, indicated that the soil in the site possesses metabolic traits linked to PCB degradation. Biphenyl-utilizing bacteria isolated from the rhizosphere of the three different plant species showed low phylogenetic diversity and well represented functional traits, in terms of PGP and bioremediation potential. On average, 72% of the strains harbored the bphA gene and/or displayed catechol 2,3-dioxygenase activity, involved in aromatic ring cleavage. PGP traits, including 1-aminocyclopropane-1-carboxylic acid deaminase activity potentially associated to plant stress tolerance induction, were widely distributed among the isolates

  11. Identification of a Toluene-Degrading Bacterium from a Soil Sample through H218O DNA Stable Isotope Probing ▿†

    PubMed Central

    Woods, Angela; Watwood, Maribeth; Schwartz, Egbert

    2011-01-01

    DNA stable isotope probing (DNA-SIP) with H218O was used to identify a toluene-degrading bacterium in soil amended with 48 ppm toluene. After quantification of toluene degradation rates in soil, DNA was extracted from soil incubated with H218O, H216O, H216O and 48 ppm toluene, or H218O and 48 ppm toluene. A single DNA band formed along a cesium chloride gradient after isopycnic centrifugation of extracts from soils incubated with H216O. With extracts from soils to which only H218O was added, two distinct DNA bands formed, while three bands formed when DNA extracted from soil incubated with both H218O and toluene was analyzed. We suggest that this third band formed because toluene does not contain any oxygen atoms and toluene-degrading organisms had to transfer oxygen atoms from H218O into metabolic intermediates to form nucleic acids de novo. We extracted the third DNA band and amplified a large fraction of the bacterial 16S rRNA gene. Direct sequencing of the PCR product obtained from the labeled DNA, as well as cloned 16S rRNA amplicons, identified a known toluene degrader, Rhodococcus jostii RHA1. A toluene-degrading bacterial strain was subsequently isolated from soil and shown to be Rhodococcus jostii RHA1. Finally, quantitative real-time PCR analysis showed that the abundance of the 16S rRNA gene of Rhodococcus jostii RHA1 increased in soil after toluene exposure but not in soils from which toluene was withheld. This study indicates that H218O DNA-SIP can be a useful method for identifying pollutant-degrading bacteria in soil. PMID:21742928

  12. Fungal degradation of an acetolactate synthase (ALS) inhibitor pyrazosulfuron-ethyl in soil.

    PubMed

    Sondhia, Shobha; Waseem, Uzma; Varma, R K

    2013-11-01

    Owing to reported phytotoxicity of some sulfonylurea class of herbicides in number of sensitive crops and higher persistence in soil, present study was conducted to isolate and identify pyrazosulfuron-ethyl degrading fungi from soil of rice field. Penicillium chrysogenum and Aspergillus niger, were isolated and identified from rhizospere soil of rice field, as potent pyrazosulfuron-ethyl degrading fungi. Degradation of pyrazosulfuron-ethyl by P. chrysogenum and A. niger, yielded transformation products/metabolites which were identified and characterized by LC/MS/MS. The rate of dissipation of pyrazosulfuron-ethyl was found higher in soil of rice field and soil inoculated with P. chrysogenum. This showed important route of degradation of pyrazosulfuron-ethyl by microbes apart from chemical degradation.

  13. Degradation of zearalenone and ochratoxin A in three Danish agricultural soils.

    PubMed

    Mortensen, Gerda K; Strobel, Bjarne W; Hansen, Hans C B

    2006-03-01

    Degradation of two mycotoxins: zearalenone (ZON) produced by species of Fusarium and ochratoxin A (OTA) produced by species of Penicillium were followed in pot experiments using agricultural topsoils from Danish experimental farms: a sandy soil, a sandy clay soil and a gyttja soil with a high content of silt. Experiments with unplanted soil and pots planted with barley were included. Soil samples were withdrawn during a period of 225 days and analysed for the content of OTA and ZON. The degradation of both toxins consisted of an initial fast degradation followed by a slower transformation step and was described well by a sum of two first-order kinetic equations. The decay first-order rate constants for the first step (k1) were in the range 0.73-2.91 d(-1) for OTA and 0.0612-0.108 d(-1) for ZON, respectively. Half-lives (t0.5) for ZON using data from the first phase were between 6.4 and 11 days, whereas the half-lives for OTA were about 0.2-1 day. The slowest degradation was measured in soil rich in clay. After 225 days, neither OTA nor ZON was detected in any of the soil types. Generally, the degradation of ZON and OTA was faster in planted soil than in unplanted soil, probably due to higher microbial activity. Due to the fast degradation of ZON and OTA in surface soil leaching as soluble substances appears to be limited.

  14. [Variation of soil physicochemical and microbial properties in degraded steppes in Hulunbeir of China].

    PubMed

    Lin, Lu; Wu, Yun-Na; Kenji, Tamura; Huo, Guang-Wei; Luo, Wen-Tao; Lü, Jian-Zhou

    2013-12-01

    To investigate the influence of degradation on grassland, we sampled soil and plants at three sites respectively under light, moderate and severe degradation in Hulunbeir Grassland in northern China and analyzed the differences and relationships among soil physicochemical characters, enzyme activity, soil microorganism quantity and aboveground biomass. The results showed that species richness of the moderately degraded site was highest while the aboveground biomass at the lightly degraded site was significantly higher than at the severely degraded site. Soil moisture content, nutrients (organic matter and total nitrogen) concentrations, soil microorganism quantity and enzyme activity were all decreased significantly in the degraded sites, whereas both the soil hardness and bulk density showed an opposite trend. The soil microbial biomass carbon and nitrogen contents ranged from 128 to 185 g x kg(-1) and from 5.6 to 13.6 g x kg(-1), respectively. The soil dehydrogenase and urease activities negatively correlated with soil bulk density but positively correlated with total nitrogen, organic matter, microbial biomass carbon and nitrogen. The aboveground biomass showed significantly positive correlation with the number of soil bacteria and fungi.

  15. Giant reed growth and effects on soil biological fertility in assisted phytoremediation of an industrial polluted soil.

    PubMed

    Fiorentino, N; Ventorino, V; Rocco, C; Cenvinzo, V; Agrelli, D; Gioia, L; Di Mola, I; Adamo, P; Pepe, O; Fagnano, M

    2017-01-01

    Phytoremediation is a cost-effective "green technology" that uses plants to improve the soil properties of polluted sites, preventing the dispersion of pollutants and reducing the mobility of potentially toxic elements (PTEs) through their adsorption and accumulation by roots or precipitation within the root zone. Being highly tolerant to pollutants and other abiotic stresses, giant reed (Arundo donax L.) is a suitable biomass crop for phytoremediation of contaminated soils. We report the results of a two-year open-air lysimeter study aimed at assessing the adaptability of giant reed to grow on industrial substrates polluted by Pb and Zn and at testing commercial humic acids from leonardite as improvers of plant performance. We evaluated giant reed potential for: 1) biomass production for energy or biomaterial recovery; 2) PTE phytoextraction and 3) soil fertility restoration. Chemical fertility was monitored by measuring soil C while soil biological fertility was estimated by quantifying the abundance of bacterial functional genes regulating nitrogen fixation (nifH) and nitrification (amoA). Giant reed above-ground growth on the polluted soils was slightly lower (-16%) than on a non-polluted soil, with a preferential storage of biomass in the rhizome acting as a survival strategy in limiting growing conditions. Humic acids improved plant stress tolerance and production levels. As aerial biomass (shoots) did not accumulate PTEs, the plant in question can be used for bioenergy or biopolymer production. In contrast, below-ground biomass (rhizomes) accumulated PTEs, and can thus be harvested and removed from soil to improve phytoremediation protocols and also used as industrial biofuel. Giant reed growth increased the abundance of N-cycling bacteria and soil C in the rhizospheric soil, as well as reduced soil Pb and Zn EDTA extractable fraction.

  16. Construction of a chemical ranking system of soil pollution substances for screening of priority soil contaminants in Korea.

    PubMed

    Jeong, Seung-Woo; An, Youn-Joo

    2012-04-01

    The Korean government recently proposed expanding the number of soil-quality standards to 30 by 2015. The objectives of our study were to construct a reasonable protocol for screening priority soil contaminants for inclusion in the planned soil quality standard expansion. The chemical ranking system of soil pollution substances (CROSS) was first developed to serve as an analytical tool in chemical scoring and ranking of possible soil pollution substances. CROSS incorporates important parameters commonly used in several previous chemical ranking and scoring systems and the new soil pollution parameters. CROSS uses soil-related parameters in its algorithm, including information related to the soil environment, such as soil ecotoxicological data, the soil toxic release inventory (TRI), and soil partitioning coefficients. Soil TRI and monitoring data were incorporated as local specific parameters. In addition, CROSS scores the transportability of chemicals in soil because soil contamination may result in groundwater contamination. Dermal toxicity was used in CROSS only to consider contact with soil. CROSS uses a certainty score to incorporate data uncertainty. CROSS scores the importance of each candidate substance and assigns rankings on the basis of total scores. Cadmium was the most highly ranked. Generally, metals were ranked higher than other substances. Pentachlorophenol, phenol, dieldrin, and methyl tert-butyl ether were ranked the highest among chlorinated compounds, aromatic compounds, pesticides, and others, respectively. The priority substance list generated from CROSS will be used in selecting substances for possible inclusion in the Korean soil quality standard expansion; it will also provide important information for designing a soil-environment management scheme.

  17. The remediation of the lead-polluted garden soil by natural zeolite.

    PubMed

    Li, Hua; Shi, Wei-yu; Shao, Hong-bo; Shao, Ming-an

    2009-09-30

    The current study investigated the remediation effect of lead-polluted garden soil by natural zeolite in terms of soil properties, Pb fraction of sequential extraction in soil and distribution of Pb in different parts of rape. Natural zeolite was added to artificially polluted garden soil to immobilize and limit the uptake of lead by rape through changing soil physical and chemical properties in the pot experiment under greenhouse conditions. Results indicated that the addition of natural zeolite could increase soil pH, CEC, content of soil organic matter and promote formation of soil aggregate. The application of zeolite decreased the available fraction of Pb in the garden soil by adjusting soil pH rather than CEC, and restrained the Pb uptake by rape. Data obtained suggested that the application of a dose of zeolite was adequate (>or=10 g kg(-1)) to reduce soluble lead significantly, even if lead pollution is severe in garden soil (>or=1000 mg kg(-1)). An appropriate dose of zeolite (20 g kg(-1)) could reduce the Pb concentration in the edible part (shoots) of rape up to 30% of Pb in the seriously polluted soil (2000 mg kg(-1)).

  18. Decontamination of electronic waste-polluted soil by ultrasound-assisted soil washing.

    PubMed

    Chen, Fu; Yang, Baodan; Ma, Jing; Qu, Junfeng; Liu, Gangjun

    2016-10-01

    Laboratorial scale experiments were performed to evaluate the efficacy of a washing process using the combination of methyl-β-cyclodextrin (MCD) and tea saponin (TS) for simultaneous desorption of hydrophobic organic contaminants (HOCs) and heavy metals from an electronic waste (e-waste) site. Ultrasonically aided mixing of the field contaminated soil with a combination of MCD and TS solutions simultaneously mobilizes most of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and the analyte metal (Pb, Cu, and Ni) burdens. It is found that 15 g/L MCD and 10 g/L TS is an efficient reagent combination reconciling extraction performance and reagent costs. Under these conditions, the removal efficiencies of HOCs and heavy metals are 93.5 and 91.2 %, respectively, after 2 cycles of 60-min ultrasound-assisted washing cycles. By contrast, 86.3 % of HOCs and 88.4 % of metals are removed from the soil in the absence of ultrasound after 3 cycles of 120-min washing. The ultrasound-assisted soil washing could generate high removal efficiency and decrease the operating time significantly. Finally, the feasibility of regenerating and reusing the spent washing solution in extracting pollutants from the soil is also demonstrated. By application of this integrated technology, it is possible to recycle the washing solution for a purpose to reduce the consumption of surfactant solutions. Collectively, it has provided an effective and economic treatment of e-waste-polluted soil.

  19. Degradation of the potato glycoalkaloid alpha-solanine in three agricultural soils.

    PubMed

    Jensen, Pia H; Pedersen, Rasmus B; Svensmark, Bo; Strobel, Bjarne W; Jacobsen, Ole Stig; Hansen, Hans Christian B

    2009-08-01

    The toxic glycoalkaloids produced by the potato plant (Solanum tuberosum L.) have previously been found in upper soil from a potato field during several months. Further insight into the fate of the glycoalkaloids is needed, as only little information about their degradation in soil is available. Degradation of the glycoalkaloid, alpha-solanine, has been followed for 42d in three agricultural soils with common texture and carbon contents. A similar degradation pattern was found in all soils, and the kinetics was well described by a sum of two first-order equations. Overall, degradation rates for the initial first reaction were in the range 0.22-1.64d(-1). Estimated half-lives were in the range 1.8-4.1d for the three top soils at 15 degrees C; the fastest degradation was observed in the sandy soil. The major proportion of alpha-solanine in the sandy soil was degraded by the fast process, while the proportion was lower for the two other soils. Fast degradation appeared to be related to the presence of low amount of sorbents. Additionally, degradation was followed at 5 degrees C in A- and C-horizon soil from the sandy location, and for both horizons the half-lives were of similar length (4.7-8.7d). For the slow process, degradation rates were in the range 0.000-0.123d(-1), and residuals were still present in all soils and all temperatures at the end of the experiment (d 42). Overall, fast degradation was found in both top- and subsoil even at low temperatures, and the risk for alpha-solanine leaching to the groundwater appears to be low.

  20. Residual impact of aged nZVI on heavy metal-polluted soils.

    PubMed

    Fajardo, C; Gil-Díaz, M; Costa, G; Alonso, J; Guerrero, A M; Nande, M; Lobo, M C; Martín, M

    2015-12-01

    In the present study, the residual toxicity and impact of aged nZVI after a leaching experiment on heavy metal (Pb, Zn) polluted soils was evaluated. No negative effects on physico-chemical soil properties were observed after aged nZVI exposure. The application of nZVI to soil produced a significant increase in Fe availability. The impact on soil biodiversity was assessed by fluorescence in situ hybridization (FISH). A significant effect of nZVI application on microbial structure has been recorded in the Pb-polluted soil nZVI-treated. Soil bacteria molecular response, evaluated by RT-qPCR using exposure biomarkers (pykA, katB) showed a decrease in the cellular activity (pykA) due to enhanced intracellular oxidative stress (katB). Moreover, ecotoxicological standardised test on Caenorhabditis elegans (C. elegans) showed a decrease in the growth endpoint in the Pb-polluted soil, and particularly in the nZVI-treated. A different pattern has been observed in Zn-polluted soils: no changes in soil biodiversity, an increase in biological activity and a significant decrease of Zn toxicity on C. elegans growth were observed after aged nZVI exposure. The results reported indicated that the pollutant and its nZVI interaction should be considered to design soil nanoremediation strategies to immobilise heavy metals.