Displaying publications 1 - 20 of 36 in total

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  1. Fulltext Cryptic footprints of rare earth elements on natural resources and living organisms
    Adeel M, Lee JY, Zain M, Rizwan M, Nawab A, Ahmad MA, et al.
    Environ Int, 2019 06;127:785-800.
    PMID: 31039528 DOI: 10.1016/j.envint.2019.03.022
    BACKGROUND: Rare earth elements (REEs) are gaining attention due to rapid rise of modern industries and technological developments in their usage and residual fingerprinting. Cryptic entry of REEs in the natural resources and environment is significant; therefore, life on earth is prone to their nasty effects. Scientific sectors have expressed concerns over the entry of REEs into food chains, which ultimately influences their intake and metabolism in the living organisms.

    OBJECTIVES: Extensive scientific collections and intensive look in to the latest explorations agglomerated in this document aim to depict the distribution of REEs in soil, sediments, surface waters and groundwater possibly around the globe. Furthermore, it draws attention towards potential risks of intensive industrialization and modern agriculture to the exposure of REEs, and their effects on living organisms. It also draws links of REEs usage and their footprints in natural resources with the major food chains involving plants, animals and humans.

    METHODS: Scientific literature preferably spanning over the last five years was obtained online from the MEDLINE and other sources publishing the latest studies on REEs distribution, properties, usage, cycling and intrusion in the environment and food-chains. Distribution of REEs in agricultural soils, sediments, surface and ground water was drawn on the global map, together with transport pathways of REEs and their cycling in the natural resources.

    RESULTS: Fourteen REEs (Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sm, Tb, Th and Yb) were plighted in this study. Wide range of their concentrations has been detected in agricultural soils (<15.9-249.1 μg g-1) and in groundwater (<3.1-146.2 μg L-1) at various sites worldwide. They have strong tendency to accumulate in the human body, and thus associated with kidney stones. The REEs could also perturb the animal physiology, especially affecting the reproductive development in both terrestrial and aquatic animals. In plants, REEs might affect the germination, root and shoot development and flowering at concentration ranging from 0.4 to 150 mg kg-1.

    CONCLUSIONS: This review article precisely narrates the current status, sources, and potential effects of REEs on plants, animals, humans health. There are also a few examples where REEs have been used to benefit human health. However, still there is scarce information about threshold levels of REEs in the soil, aquatic, and terrestrial resources as well as living entities. Therefore, an aggressive effort is required for global action to generate more data on REEs. This implies we prescribe an urgent need for inter-disciplinary studies about REEs in order to identify their toxic effects on both ecosystems and organisms.

    Matched MeSH terms: Soil Pollutants/chemistry*
  2. The impact of biochars on sorption and biodegradation of polycyclic aromatic hydrocarbons in soils--a review
    Anyika C, Abdul Majid Z, Ibrahim Z, Zakaria MP, Yahya A
    Environ Sci Pollut Res Int, 2015 Mar;22(5):3314-41.
    PMID: 25345923 DOI: 10.1007/s11356-014-3719-5
    Amending polycyclic aromatic hydrocarbon (PAH)-contaminated soils with biochar may be cheaper and environmentally friendly than other forms of organic materials. This has led to numerous studies on the use of biochar to either bind or stimulate the microbial degradation of organic compounds in soils. However, very little or no attention have been paid to the fact that biochars can give simultaneous impact on PAH fate processes, such as volatilization, sorption and biodegradation. In this review, we raised and considered the following questions: How does biochar affect microbes and microbial activities in the soil? What are the effects of adding biochar on sorption of PAHs? What are the effects of adding biochar on degradation of PAHs? What are the factors that we can manipulate in the laboratory to enhance the capability of biochars to degrade PAHs? A triphasic concept of how biochar can give simultaneous impact on PAH fate processes in soils was proposed, which involves rapid PAH sorption into biochar, subsequent desorption and modification of soil physicochemical properties by biochar, which in turn stimulates microbial degradation of the desorbed PAHs. It is anticipated that biochar can give simultaneous impact on PAH fate processes in soils.
    Matched MeSH terms: Soil Pollutants/chemistry*
  3. Fulltext Chemical speciation and potential mobility of heavy metals in the soil of former tin mining catchment
    Ashraf MA, Maah MJ, Yusoff I
    ScientificWorldJournal, 2012;2012:125608.
    PMID: 22566758 DOI: 10.1100/2012/125608
    This study describes the chemical speciation of Pb, Zn, Cu, Cr, As, and Sn in soil of former tin mining catchment. Total five sites were selected for sampling and subsequent subsamples were collected from each site in order to create a composite sample for analysis. Samples were analysed by the sequential extraction procedure using optical emission spectrometry (ICP OES). Small amounts of Cu, Cr, and As retrieved from the exchangeable phase, the ready available for biogeochemical cycles in the ecosystem. Low quantities of Cu and As could be taken up by plants in these kind of acidic soils. Zn not detected in the bioavailable forms while Pb is only present in negligible amounts in very few samples. The absence of mobile forms of Pb eliminates the toxic risk both in the trophic chain and its migration downwards the soil profile. The results also indicate that most of the metals have high abundance in residual fraction indicating lithogenic origin and low bioavailability of the metals in the studied soil. The average potential mobility for the metals giving the following order: Sn > Cu > Zn > Pb > Cr > As.
    Matched MeSH terms: Soil Pollutants/chemistry*
  4. Degradation of chlorpyrifos in humid tropical soils
    Chai LK, Wong MH, Bruun Hansen HC
    J Environ Manage, 2013 Aug 15;125:28-32.
    PMID: 23632002 DOI: 10.1016/j.jenvman.2013.04.005
    The insecticide chlorpyrifos is extensively used in the humid tropics for insect control on crops and soils. Chlorpyrifos degradation and mineralization was studied under laboratory conditions to characterize the critical factors controlling the degradation and mineralization in three humid tropical soils from Malaysia. The degradation was fastest in moist soils (t1/2 53.3-77.0 days), compared to dry (t1/2 49.5-120 days) and wet soils (t1/2 63.0-124 days). Degradation increased markedly with temperature with activation energies of 29.0-76.5 kJ mol(-1). Abiotic degradation which is important for chlorpyrifos degradation in sub-soils containing less soil microbial populations resulted in t½ of 173-257 days. Higher chlorpyrifos dosages (5-fold) which are often applied in the tropics due to severe insects infestations caused degradation and mineralization rates to decrease by 2-fold. The mineralization rates were more sensitive to the chlorpyrifos application rates reflecting that degradation of metabolites is rate limiting and the toxic effects of some of the metabolites produced. Despite that chlorpyrifos is frequently used and often in larger amounts on tropical soils compared with temperate soils, higher temperature, moderate moisture and high activity of soil microorganisms will stimulate degradation and mineralization.
    Matched MeSH terms: Soil Pollutants/chemistry*
  5. Degradation and mineralization kinetics of acephate in humid tropic soils of Malaysia
    Chai LK, Wong MH, Mohd-Tahir N, Hansen HC
    Chemosphere, 2010 Apr;79(4):434-40.
    PMID: 20189217 DOI: 10.1016/j.chemosphere.2010.01.046
    Acephate is poorly sorbed to soil, thus the risk of leaching to the aquatic environment is high if it is not quickly degraded. The effect of soil moisture, temperature, microbial activity and application rate on acephate degradation has been studied in three Malaysian soils to examine and identify critical variables determining its degradation and mineralization kinetics. First-order kinetics could be used to describe degradation in all cases (r(2)>0.91). Acephate degraded faster in air-dry (t((1/2)) 9-11 d) and field capacity (t((1/2)) 10-16d) soils than in the wet soils (t((1/2)) 32-77 d). The activation energy of degradation was in the range 17-28 kJ mol(-1) and significantly higher for the soil with higher pH and lower clay and iron oxide contents. Soil sterilization caused a 3- to 10-fold decrease in degradation rates compared to non-sterile soils (t((1/2)) 53-116 d) demonstrating that acephate degradation is mainly governed by microbial processes. At 5-fold increase in application rates (25 microg g(-1)), half-life increased slightly (t((1/2)) 13-19 d) or was unaffected. Half-life from acephate mineralization was similar to those from degradation but much longer at the 5-fold increase in acephate application rates (t((1/2)) 41-96 d) demonstrating that degradation of metabolites is rate limiting. Thus, application of acephate should be restricted or avoided during wet seasons with heavy rainfall and flooded soil as in paddy cultivation. Sandy soils with low microbial activity are more prone to acephate leaching than clay soils rich in humic matter.
    Matched MeSH terms: Soil Pollutants/chemistry
  6. Effect of different oxytetracycline addition methods on its degradation behavior in soil
    Chen GX, He WW, Wang Y, Zou YD, Liang JB, Liao XD, et al.
    Sci Total Environ, 2014 May 1;479-480:241-6.
    PMID: 24561929 DOI: 10.1016/j.scitotenv.2014.01.124
    The degradation behavior of veterinary antibiotics in soil is commonly studied using the following methods of adding antibiotics to the soil: (i) adding manure collected from animals fed with a diet containing antibiotics, (ii) adding antibiotic-free animal manure spiked with antibiotics and (iii) directly adding antibiotics. No research simultaneously comparing different antibiotic addition methods was found. Oxytetracycline (OTC) was used as a model antibiotic to compare the effect of the three commonly used antibiotic addition methods on OTC degradation behavior in soil. The three treatment methods have similar trends, though OTC degradation half-lives show the following significant differences (P<0.05): manure from swine fed OTC (treatment A)soil. Because the main entry route for veterinary antibiotics into soil is via the manure of animals given with antibiotics, the most appropriate method to study the degradation and ecotoxicity of antibiotic residues in soil may be to use manure from animals that are given a particular antibiotic, rather than by adding it directly to the soil.
    Matched MeSH terms: Soil Pollutants/chemistry*
  7. Growth kinetics of a diesel-degrading bacterial strain from petroleum-contaminated soil
    Dahalan SF, Yunus I, Johari WL, Shukor MY, Halmi MI, Shamaan NA, et al.
    J Environ Biol, 2014 Mar;35(2):399-406.
    PMID: 24665769
    A diesel-degrading bacterium was isolated from a diesel-contaminated site in Selangor, Malaysia. The isolate was tentatively identified as Acinetobacter sp. strain DRY12 based on partial 16S rDNA molecular phylogeny and Biolog GN microplate panels and Microlog database. Optimum growth occurred from 3 to 5% diesel and the strain was able to tolerate as high as 8% diesel. The optimal pH that supported growth of the bacterium was between pH 7.5 to 8.0. The isolate exhibited optimal growth in between 30 and 35 degrees C. The best nitrogen source was potassium nitrate (between 0.6 and 0.9% (w/v)) followed by ammonium chloride, sodium nitrite and ammonium sulphate in descending order. An almost complete removal of diesel components was seen from the reduction in hydrocarbon peaks observed using Solid Phase Microextraction Gas Chromatography analysis after 10 days of incubation. The best growth kinetic model to fit experimental data was the Haldane model of substrate inhibiting growth with a correlation coefficient value of 0.97. The maximum growth rate- micromax was 0.039 hr(-1) while the saturation constant or half velocity constant Ks and inhibition constant Ki, were 0.387% and 4.46%, respectively. MATH assays showed that 75% of the bacterium was found in the hexadecane phase indicating that the bacterium was hydrophobic. The characteristics of this bacterium make it useful for bioremediation works in the Tropics.
    Matched MeSH terms: Soil Pollutants/chemistry
  8. Study on the downward movement of carbofuran in two Malaysian soils
    Farahani GH, Sahid IB, Zakaria Z, Kuntom A, Omar D
    Bull Environ Contam Toxicol, 2008 Sep;81(3):294-8.
    PMID: 18587522 DOI: 10.1007/s00128-008-9468-8
    The downward movement of carbofuran in two Malaysian soil types was studied using soil columns. The columns were filled with disturbed and undisturbed soils of either the Bagan Datoh soil (clay) or the Labu soil (sandy clay). The average total percentage of carbofuran in the leachate of the undisturbed Labu soil after 14 days of watering (80.8%) was approximately similar to that of the total amount from the disturbed soil (81.4%). However, carbofuran leaching was observed in the disturbed soil after the fourth day of watering whereas for the undisturbed soil, leaching occurred after the first watering. A similar trend was observed in the Bagan Datoh soil where the residue of carbofuran was detected after the first day of watering in the undisturbed soil column but only at the eighth day of watering in the disturbed soil column. The total percentage carbofuran in the leachate of disturbed and undisturbed soil columns from Bagan Datoh after 14 days of watering was 3.6% and 41.7%, respectively. The study showed that less leaching occurred in soil columns with high organic content such as the Bagan Datoh soil and especially so in disturbed soils where the organic matter was homogeneously mixed in all layers.
    Matched MeSH terms: Soil Pollutants/chemistry
  9. Investigation of the impacts of ethyl lactate based Fenton treatment on soil quality for polycyclic aromatic hydrocarbons (PAHs)-contaminated soils
    Gan S, Yap CL, Ng HK, Venny
    J Hazard Mater, 2013 Nov 15;262:691-700.
    PMID: 24121640 DOI: 10.1016/j.jhazmat.2013.09.023
    This study aims to investigate the impacts of ethyl lactate (EL) based Fenton treatment on soil quality for polycyclic aromatic hydrocarbons (PAHs)-contaminated soils. Accumulation of oxygenated-polycyclic aromatic hydrocarbons (oxy-PAHs) was observed, but quantitative measurement on the most abundant compound 9,10-anthraquinone (ATQ) showed lower accumulation of the compound than that reported for ethanol (ET) based Fenton treatment. In general, as compared to conventional water (CW) based Fenton treatment, the EL based Fenton treatment exerted either a lower or higher negative impact on soil physicochemical properties depending on the property type and shared the main disadvantage of reduced soil pH. For revegetation, EL based Fenton treatment was most appropriately adopted for soil with native pH >/~ 6.2 in order to obtain a final soil pH >/~ 4.9 subject to the soil buffering capacity.
    Matched MeSH terms: Soil Pollutants/chemistry*
  10. Remediation of soils contaminated with polycyclic aromatic hydrocarbons (PAHs)
    Gan S, Lau EV, Ng HK
    J Hazard Mater, 2009 Dec 30;172(2-3):532-49.
    PMID: 19700241 DOI: 10.1016/j.jhazmat.2009.07.118
    Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic micropollutants which are resistant to environmental degradation due to their highly hydrophobic nature. Concerns over their adverse health effects have resulted in extensive studies on the remediation of soils contaminated with PAHs. This paper aims to provide a review of the remediation technologies specifically for PAH-contaminated soils. The technologies discussed here include solvent extraction, bioremediation, phytoremediation, chemical oxidation, photocatalytic degradation, electrokinetic remediation, thermal treatment and integrated remediation technologies. For each of these, the theories are discussed in conjunction with comparative evaluation of studies reported in the specialised literature.
    Matched MeSH terms: Soil Pollutants/chemistry*
  11. Fulltext Degradation of Triazine-2-(14)C Metsulfuron-Methyl in Soil from an Oil Palm Plantation
    Ismail BS, Eng OK, Tayeb MA
    PLoS One, 2015;10(10):e0138170.
    PMID: 26437264 DOI: 10.1371/journal.pone.0138170
    Triazine-2-(14)C metsulfuron-methyl is a selective, systemic sulfonylurea herbicide. Degradation studies in soils are essential for the evaluation of the persistence of pesticides and their breakdown products. The purpose of the present study was to investigate the degradation of triazine-2-(14)C metsulfuron-methyl in soil under laboratory conditions. A High Performance Liquid Chromatograph (HPLC) equipped with an UV detector and an on-line radio-chemical detector, plus a Supelco Discovery column (250 x 4.6 mm, 5 μm), and PRP-1 column (305 x 7.0 mm, 10 μm) was used for the HPLC analysis. The radioactivity was determined by a Liquid Scintillation Counter (LSC) in scintillation fluid. The soil used was both sterilized and non-sterilized in order to observe the involvement of soil microbes. The estimated DT50 and DT90 values of metsulfuron-methyl in a non-sterile system were observed to be 13 and 44 days, whereas in sterilized soil, the DT50 and DT90 were 31 and 70 days, respectively. The principal degradation product after 60 days was CO2. The higher cumulative amount of (14)CO2 in (14)C-triazine in the non-sterilized soil compared to that in the sterile system suggests that biological degradation by soil micro-organisms significantly contributes to the dissipation of the compound. The major routes of degradation were O-demethylation, sulfonylurea bridge cleavage and the triazine "ring-opened."
    Matched MeSH terms: Soil Pollutants/chemistry*
  12. Investigation of ethyl lactate as a green solvent for desorption of total petroleum hydrocarbons (TPH) from contaminated soil
    Jalilian Ahmadkalaei SP, Gan S, Ng HK, Abdul Talib S
    Environ Sci Pollut Res Int, 2016 Nov;23(21):22008-22018.
    PMID: 27539472
    Treatment of oil-contaminated soil is a major environmental concern worldwide. The aim of this study is to examine the applicability of a green solvent, ethyl lactate (EL), in desorption of diesel aliphatic fraction within total petroleum hydrocarbons (TPH) in contaminated soil and to determine the associated desorption kinetics. Batch desorption experiments were carried out on artificially contaminated soil at different EL solvent percentages (%). In analysing the diesel range of TPH, TPH was divided into three fractions and the effect of solvent extraction on each fraction was examined. The experimental results demonstrated that EL has a high and fast desorbing power. Pseudo-second order rate equation described the experimental desorption kinetics data well with correlation coefficient values, R (2), between 0.9219 and 0.9999. The effects of EL percentage, initial contamination level of soil and liquid to solid ratio (L/S (v/w)) on initial desorption rate have also been evaluated. The effective desorption performance of ethyl lactate shows its potential as a removal agent for remediation of TPH-contaminated soil worldwide.
    Matched MeSH terms: Soil Pollutants/chemistry*
  13. Effective remediation of phenol,2,4-bis(1,1-dimethylethyl) and bis(2-ethylhexyl) phthalate in farm effluent using Guar gum--A plant based biopolymer
    Kee YL, Mukherjee S, Pariatamby A
    Chemosphere, 2015 Oct;136:111-7.
    PMID: 25966329 DOI: 10.1016/j.chemosphere.2015.04.074
    This study was carried out to evaluate the efficiency of Guar gum in removing Persistent Organic Pollutants (POPs), viz. phenol,2,4-bis(1,1-dimethylethyl) and bis(2-ethylhexyl) phthalate (DEHP), from farm effluent. The removal efficiency was compared with alum. The results indicated that 4.0 mg L(-1) of Guar gum at pH 7 could remove 99.70% and 99.99% of phenol,2,4-bis(1,1-dimethylethyl) and DEHP, respectively. Box Behnken design was used for optimization of the operating parameters for optimal POPs removal. Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy studies were conducted on the flocs. SEM micrographs showed numerous void spaces in the flocs produced by Guar gum as opposed to those produced by alum. This indicated why Guar gum was more effective in capturing and removal of suspended particles and POPs as compared to alum. FTIR spectra indicated a shift in the bonding of functional groups in the flocs produced by Guar gum as compared to raw Guar gum powder signifying chemical attachment of the organics present in the effluent to the coagulant resulting in their removal. Guar gum is highly recommended as a substitute to chemical coagulant in treating POPs due to its non-toxic and biodegradable characteristics.
    Matched MeSH terms: Soil Pollutants/chemistry*
  14. Extraction agents for the removal of polycyclic aromatic hydrocarbons (PAHs) from soil in soil washing technologies
    Lau EV, Gan S, Ng HK, Poh PE
    Environ Pollut, 2014 Jan;184:640-9.
    PMID: 24100092 DOI: 10.1016/j.envpol.2013.09.010
    Polycyclic aromatic hydrocarbons (PAHs) in soil have been recognised as a serious health and environmental issue due to their carcinogenic, mutagenic and teratogenic properties. One of the commonly employed soil remediation techniques to clean up such contamination is soil washing or solvent extraction. The main factor which governs the efficiency of this process is the solubility of PAHs in the extraction agent. Past field-scale soil washing treatments for PAH-contaminated soil have mainly employed organic solvents or water which is either toxic and costly or inefficient in removing higher molecular weight PAHs. Thus, the present article aims to provide a review and discussion of the alternative extraction agents that have been studied, including surfactants, biosurfactants, microemulsions, natural surfactants, cyclodextrins, vegetable oil and solution with solid phase particles. These extraction agents have been found to remove PAHs from soil at percentages ranging from 47 to 100% for various PAHs.
    Matched MeSH terms: Soil Pollutants/chemistry*
  15. Colloid mobilization and heavy metal transport in the sampling of soil solution from Duckum soil in South Korea
    Lee S, Ko IW, Yoon IH, Kim DW, Kim KW
    Environ Geochem Health, 2019 Feb;41(1):469-480.
    PMID: 29574658 DOI: 10.1007/s10653-018-0099-7
    Colloid mobilization is a significant process governing colloid-associated transport of heavy metals in subsurface environments. It has been studied for the last three decades to understand this process. However, colloid mobilization and heavy metal transport in soil solutions have rarely been studied using soils in South Korea. We investigated the colloid mobilization in a variety of flow rates during sampling soil solutions in sand columns. The colloid concentrations were increased at low flow rates and in saturated regimes. Colloid concentrations increased 1000-fold higher at pH 9.2 than at pH 7.3 in the absence of 10 mM NaCl solution. In addition, those were fourfold higher in the absence than in the presence of the NaCl solution at pH 9.2. It was suggested that the mobility of colloids should be enhanced in porous media under the basic conditions and the low ionic strength. In real field soils, the concentrations of As, Cr, and Pb in soil solutions increased with the increase in colloid concentrations at initial momentarily changed soil water pressure, whereas the concentrations of Cd, Cu, Fe, Ni, Al, and Co lagged behind the colloid release. Therefore, physicochemical changes and heavy metal characteristics have important implications for colloid-facilitated transport during sampling soil solutions.
    Matched MeSH terms: Soil Pollutants/chemistry*
  16. Adsorption, desorption and mobility of cyfluthrin in three Malaysian tropical soils of different textures
    Lsmail BS, Choo LY, Salmijah S, Halimah M, Tayeb MA
    J Environ Biol, 2015 Sep;36(5):1105-11.
    PMID: 26521552
    The sorption and desorption of cyfluthrin mixture isomers were determined using batch equilibration method and mobility was studied under laboratory conditions, using packed soil column. The soil types used in the study were clayey, clay loam and sandy clay loam obtained from three tomato farms in Cameron Highlands. A low Freundlich adsorption distribution coefficient K(ads(f)) for cyfluthrin was observed for clayey, clay loam and sandy clay loam soils (95.69, 21.64 and 8.99 l/kg, respectively). Results showed that cyfluthrin had high Freundlich organic matter (OM) distribution coefficient K(oc) values of 5799, 2278 and 1635 lkg(-1) for clayey, clay loam and sandy clay loam soils, respectively. These values indicate that cyfluthrin is considered immobile in Malaysian soils with different textures, based on the value of K(oc) by McCall. Adsorption of cyfluthrin was significantly (P < 0.05) affected with soil pH, fertilizer NPK, organic matter content and temperature. It was observed that approximately 95.8%, 93.8% and 91.8% of the adsorbed cyfluthrin remained sorbed after four successive rinses for clayey, clay loam and sandy clay loam soils. Soil column test showed that cyfluthrin was not detected in leachate. Cyfluthrin was detected in topsoil and its concentration decreased with depth. The downward movement of cyfluthrin in sandy clay loam soil was more than that in clay loam and clayey soils. Approximately, 80.9%, 77.8% and 67.3% cyfluthrin was observed at the depth of 0-5 cm (rainfall 350 mm) for clayey, clay loam and sandy clay loam soils respectively. Mobility of cyfluthrin showed that the percentage of cyfluthrin leached into soil was not affected by the amount of rainfall. The result clearly showed that cyfluthrin molecules were bound strongly to all the three Malaysian soil types.
    Matched MeSH terms: Soil Pollutants/chemistry*
  17. Ex-situ bioremediation of crude oil in soil, a comparative kinetic analysis
    Mohajeri L, Aziz HA, Isa MH, Zahed MA, Mohajeri S
    Bull Environ Contam Toxicol, 2010 Jul;85(1):54-8.
    PMID: 20577869 DOI: 10.1007/s00128-010-0058-1
    Weathered crude oil (WCO) removals in shoreline sediment samples were monitored for 60 days in bioremediation experimentation. Experimental modeling was carried out using statistical design of experiments. At optimum conditions maximum of 83.13, 78.06 and 69.92% WCO removals were observed for 2, 16 and 30 g/kg initial oil concentrations, respectively. Significant variations in the crude oil degradation pattern were observed with respect to oil, nutrient and microorganism contents. Crude oil bioremediation were successfully described by a first-order kinetic model. The study indicated that the rate of hydrocarbon biodegradation increased with decrease of crude oil concentrations.
    Matched MeSH terms: Soil Pollutants/chemistry
  18. Soil chemistry and pollution study of a closed landfill site at Ampar Tenang, Selangor, Malaysia
    Mohd Adnan SN, Yusoff S, Piaw CY
    Waste Manag Res, 2013 Jun;31(6):599-612.
    PMID: 23528999 DOI: 10.1177/0734242X13482031
    A total of 20 landfills are located in State of Selangor, Malaysia. This includes the Ampar Tenang landfill site, which was closed on 26 January 2010. It was reported that the landfill has been upgraded to a level I type of sanitary classification. However, the dumpsite area is not being covered according to the classification. In addition, municipal solid waste was dumped directly on top of the unlined natural alluvium formation. This does not only contaminate surface and subsurface soils, but also initiates the potential risk of groundwater pollution. Based on previous studies, the Ampar Tenang soil has been proven to no longer be capable of preventing pollution migration. In this study, metal concentrations of soil samples up to 30 m depth were analyzed based on statistical analysis. It is very significant because research of this type has not been carried out before. The subsurface soils were significantly polluted by arsenic (As), lead (Pb), iron (Fe), copper (Cu) and aluminium (Al). As and Pb exceeded the safe limit values of 5.90 mg/kg and 31.00 mg/kg, respectively, based on Provincial Sediment Quality Guidelines for Metals and the Interim Sediment Quality Values. Furthermore, only Cu concentrations showed a significantly decreasing trend with increasing depth. Most metals were found on clay-type soils based on the cluster analysis method. Moreover, the analysis also differentiates two clusters: cluster I-Pb, As, zinc, Cu, manganese, calcium, sodium, magnesium, potassium and Fe; cluster II-Al. Different clustering may suggest a different contamination source of metals.
    Matched MeSH terms: Soil Pollutants/chemistry*
  19. Adsorption study of 14C-paraquat in two Malaysian agricultural soils
    Muhamad H, Ismail BS, Sameni M, Mat N
    Environ Monit Assess, 2011 May;176(1-4):43-50.
    PMID: 20582739 DOI: 10.1007/s10661-010-1565-6
    The adsorption equilibrium time and effects of pH and concentration of (14)C-labeled paraquat (1,1(')-dimethyl-4,4(')-bipyridylium dichloride) in two types of Malaysian soil were investigated. The soils used in the study were clay loam and clay soils from rice fields. Equilibrium studies of paraquat in a soil and pesticide solution were conducted. Adsorption equilibrium time was achieved within 2 h for both soil types. The amount of (14)C-labeled paraquat adsorbed onto glass surfaces increased with increasing shaking time and remained constant after 10 h. It was found that paraquat adsorbed by the two soils was very similar: 51.73 (clay loam) and 51.59 μ g g(-1) (clay) at 1 μ g/ml. The adsorption of paraquat onto both types of soil was higher at high pH, and adsorption decreased with decreasing pH. At pH 11, the amounts of (14)C-labeled paraquat adsorbed onto the clay loam and clay soil samples were 4.08 and 4.05 μ g g(-1), respectively, whereas at pH 2, the amounts adsorbed were 3.72 and 3.57 μ g g(-1), respectively. Results also suggested that paraquat sorption by soil is concentration dependent.
    Matched MeSH terms: Soil Pollutants/chemistry*
  20. Application of colloidal gas aphron suspensions produced from Sapindus mukorossi for arsenic removal from contaminated soil
    Mukhopadhyay S, Mukherjee S, Hashim MA, Sen Gupta B
    Chemosphere, 2015 Jan;119:355-362.
    PMID: 25061940 DOI: 10.1016/j.chemosphere.2014.06.087
    Colloidal gas aphron dispersions (CGAs) can be described as a system of microbubbles suspended homogenously in a liquid matrix. This work examines the performance of CGAs in comparison to surfactant solutions for washing low levels of arsenic from an iron rich soil. Sodium Dodecyl Sulfate (SDS) and saponin, a biodegradable surfactant, obtained from Sapindus mukorossi or soapnut fruit were used for generating CGAs and solutions for soil washing. Column washing experiments were performed in down-flow and up flow modes at a soil pH of 5 and 6 using varying concentration of SDS and soapnut solutions as well as CGAs. Soapnut CGAs removed more than 70% arsenic while SDS CGAs removed up to 55% arsenic from the soil columns in the soil pH range of 5-6. CGAs and solutions showed comparable performances in all the cases. CGAs were more economical since it contains 35% of air by volume, thereby requiring less surfactant. Micellar solubilization and low pH of soapnut facilitated arsenic desorption from soil column. FT-IR analysis of effluent suggested that soapnut solution did not interact chemically with arsenic thereby facilitating the recovery of soapnut solution by precipitating the arsenic. Damage to soil was minimal arsenic confirmed by metal dissolution from soil surface and SEM micrograph.
    Matched MeSH terms: Soil Pollutants/chemistry*
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