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Adsorption of Remazol Red 198 onto magnetic N-lauryl chitosan particles: equilibrium, kinetics, reuse and factorial design
2012
PURPOSE: The discharge of colored effluents from industries is an important environmental issue and it is indispensable to remove the dyes before the water gets back to the rivers. The magnetic adsorbents present the advantage of being easily separated from the aqueous system after adsorption by positioning an external magnetic field. METHODS: Magnetic N-lauryl chitosan (L-Cht/γ-Fe2O3) particles were prepared and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, and vibrating sample magnetometry. Remazol Red 198 (RR198) was used as a reactive dye model for adsorption on L-Cht/γ-Fe2O3. The adsorption isotherms were performed at 25°C, 35°C, 45°C, and 55°C and the process was optimized using a 23 factorial design (analyzed factors: pH, ionic strength, and temperature). The desorption and regeneration studies were performed in a three times cycle. RESULTS: The characterization of the material indicated that the magnetic particles were introduced into the polymeric matrix. The pseudo-second order was the best model for explaining the kinetics and the Langmuir–Freundlich was the best-fitted isotherm model. At room temperature, the maximum adsorption capacity was 267 mg g−1. The material can be reused, but with a decrease in the amount of adsorbed dye. CONCLUSIONS: L-Cht/γ-Fe2O3 is a promising material to remove RR198 and probably other similar reactive dyes from aqueous effluents.
Show more [+] Less [-]Exposure assessment of pesticides in a shallow groundwater of the Tagus vulnerable zone (Portugal): a multivariate statistical approach (JCA)
2012
Silva, Emília | Mendes, Maria Paula | Ribeiro, Luis | Cerejeira, Maria José
PURPOSE: To assess groundwater exposure to pesticides, in agricultural areas of ‘Ribatejo’ region (Portugal), and the influence of some key factors in that exposure, field, laboratory and modelling studies were carried out. METHODS: The study was performed in maize, potato, sugar beet, tomato and vegetables agricultural areas, located in a shallow aquifer, with pesticides use and, in most cases, with irrigation practices. Pesticides used in the studied agricultural areas and having leaching potential were selected, being considered also other pesticides included in priority lists, defined in Europe. Evaluation of groundwater exposure to pesticides was carried out by successively: (1) groundwater sampling in seven campaigns over the period 2004–2006; (2) pesticide analysis [including isolation and concentration from the groundwater samples and further determination by gas chromatography–mass spectrometry (GC–MS) of 14 herbicides, four insecticides and two metabolites]; and (3) analysis and discussion of the results by applying joint correspondence analysis (JCA). RESULTS: From the 20 pesticides and metabolites selected for the study, 11 were found in groundwater. Pesticides and metabolites most frequently detected were atrazine, alachlor, metolachlor, desethylatrazine, ethofumesate, α-endosulfan, metribuzine, lindane and β-endosulfan. The results showed that groundwater exposure to pesticides is influenced by local factors—either environmental or agricultural, as precipitation, soil, geology, crops and irrigation practices. Spring and autumn were more associated with the detection of pesticides being more likely to observe mixtures of these compounds in a groundwater sample in these transition seasons. CONCLUSIONS: This work evidences the importance of models, which evaluate pesticides environmental behaviour, namely their water contamination potential (as Mackay multicompartimental fugacity model) and, specially, groundwater contamination potential (as GUS and Bacci and Gaggi leaching indices), in pesticide selection. Moreover, it reveals the importance to adapt proper statistical methods according to level of left-censored data. Using JCA was still possible to establish relations between pesticides and their temporal trend in a case study where there were more than 80% of data censored. This study will contribute to the Tagus river basin management plan with information on the patterns of pesticide occurrence in the alluvial aquifer system.
Show more [+] Less [-]Natural attenuation is enhanced in previously contaminated and coniferous forest soils
2012
Kauppi, Sari | Romantschuk, Martin | Strömmer, Rauni | Sinkkonen, Aki
PURPOSE: Prevalence of organic pollutants or their natural analogs in soil is often assumed to lead to adaptation in the bacterial community, which results in enhanced bioremediation if the soil is later contaminated. In this study, the effects of soil type and contamination history on diesel oil degradation and bacterial adaptation were studied. METHODS: Mesocosms of mineral and organic forest soil (humus) were artificially treated with diesel oil, and oil hydrocarbon concentrations (GC-FID), bacterial community composition (denaturing gradient gel electrophoresis, DGGE), and oil hydrocarbon degraders (DGGE + sequencing of 16S rRNA genes) were monitored for 20 weeks at 16°C. RESULTS: Degradation was advanced in previously contaminated soils as compared with pristine soils and in coniferous organic forest soil as compared with mineral soil. Contamination affected bacterial community composition especially in the pristine mineral soil, where diesel addition increased the number of strong bands in the DGGE gel. Sequencing of cloned 16S rRNA gene fragments and DGGE bands showed that potential oil-degrading bacteria were found in mineral and organic soils and in both pristine and previously contaminated mesocosms. Fast oil degradation was not associated with the presence of any particular bacterial strain in soil. CONCLUSIONS: We demonstrate at the mesocosm scale that previously contaminated and coniferous organic soils are superior environments for fast oil degradation as compared with pristine and mineral soil environments. These results may be utilized in preventing soil pollution and planning soil remediation.
Show more [+] Less [-]Effects of perinatal exposure to bisphenol A and di(2-ethylhexyl)-phthalate on gonadal development of male mice
2012
Xi, Wei | Wan, H. T. | Zhao, Y. G. | Wong, M. H. | Giesy, John P. | Wong, Chris K. C.
PURPOSE: In this study, we investigated the effects of maternal transfer of bisphenol A (BPA) and di(2-ethylhexyl) phthalate (DEHP) during gestational and weaning periods on gonadal development of male offspring. METHODS: Pregnant CD-1 mice were administered by gavages in corn oil with 0.1, 1, or 10 mg/kg/day of BPA and DEHP from gestational days (GD1–21) to the weaning period (postnatal days (PND) 1–21). RESULTS: Our data indicated that the exposure significantly reduced the male-to-female sex ratio and the sizes of the gonads of male pups as recorded at PND15. The testes of the perinatally exposed male pups were developed less and the expression levels of testicular anti-mullerian hormone, androgen receptor, cyclin A, and StAR were significantly lesser than the control male pups. The less developed testes were accompanied with significant reductions in the expression levels of Gnrh and Fsh at the hypothalamic–pituitary levels. The negative effects were found to be persistent in the sexually mature pups at PND42. CONCLUSION: Our data reveal that the maternal transfer of BPA and DEHP may impose negative influence on the development and functions of the reproductive system of male pups.
Show more [+] Less [-]Polychlorinated biphenyls and their hydroxylated metabolites in placenta from Madrid mothers
2012
Gómara, Belén | Athanasiadou, Maria | Quintanilla-López, Jesús Eduardo | González, María José | Bergman, Åke
INTRODUCTION: Concentrations and congener profiles of polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs) in placenta samples from a Madrid population (Spain) are reported. Structure dependent retentions of OH-PCBs are known to occur in both humans and wildlife, making it of interest to assess placental transfer of both parent compounds and their metabolites to the developing foetus. RESULTS: The ΣPCB concentrations found in placenta samples were in the range 943–4,331 pg/g fresh weight (f.w.), and their hydroxylated metabolites showed a 20-time lower concentration level (53–261 pg/g f.w.). The PCB profiles were surprisingly dominated by CB-52 and CB-101 accounting for more than 44% of the total PCB concentration. This is indicating a source of exposure that is not yet identified. The OH-PCB profiles were dominated by 4-OH-CB187 and 4-OH-CB146, representing >50% of the ΣOH-PCB concentration of the placenta samples. Statistical analysis of the data revealed strong correlations between the PCB congeners, among some OH-PCBs, and between OH-PCB metabolites with a meta- and para- substitution pattern. Both PCB and OH-PCB concentrations presented homogeneous distribution, what allowed the establishment of a partial least squares model that correlated the concentrations of OH-PCB with those of PCBs in placenta samples. In addition, causal correlations were observed between the concentrations of OH-PCBs and those of their corresponding PCB precursors.
Show more [+] Less [-]Perfluorooctanoic acid (PFOA) acts as a tumor promoter on Syrian hamster embryo (SHE) cells
2012
Jacquet, N. | Maire, M. A. | Rast, C. | Bonnard, M. | Vasseur, P.
Perfluorooctane sulfonate (PFOS) (C₈F₁₇SO₃) and perfluorooctanoic acid (PFOA) (C₈HF₁₅O₂) are synthetic chemicals widely used in industrial applications for their hydrophobic and oleophobic properties. They are persistent, bioaccumulative, and toxic to mammalian species. Their widespread distribution on earth and contamination of human serum raised concerns about long-term side effects. They are suspected to be carcinogenic through a nongenotoxic mode of action, a mechanism supported by recent findings that PFOS induced cell transformation but no genotoxicity in Syrian hamster embryo (SHE) cells. In the present study, we evaluated carcinogenic potential of PFOA using the cell transformation assay on SHE cells. The chemical was applied alone or in combination with a nontransformant concentration of benzo[a]pyrene (BaP, 0.4 μM) in order to detect PFOA ability to act as tumor initiator or tumor promoter. The results showed that PFOA tested alone in the range 3.7 × 10⁻⁵ to 300 μM did not induce SHE cell transformation frequency in a 7-day treatment. On the other side, the combination BaP/PFOA induced cell transformation at all PFOA concentrations tested, which revealed synergistic effects. No genotoxicity of PFOA on SHE cells was detected using the comet assay after 5 and 24 h of exposure. No significant increase in DNA breakage was found in BaP-initiated cells exposed to PFOA in a 7-day treatment. The whole results showed that PFOA acts as a tumor promoter and a nongenotoxic carcinogen. Cell transformation in initiated cells was observed at concentrations equivalent to the ones found in human serum of nonoccupationally and occupationally exposed populations. An involvement of PFOA in increased incidence of cancer recorded in occupationally exposed population cannot be ruled out.
Show more [+] Less [-]Possible use of Serratia marcescens in toxic metal biosorption (removal)
2012
Cristani, Mariateresa | Naccari, Clara | Nostro, Antonia | Pizzimenti, Alessia | Trombetta, Domenico | Pizzimenti, Francesco
BACKGROUND, AIM AND SCOPE: Metal pollution is a serious problem for environmental safety and programmes of monitoring and bioremediation are needed. Among the processes of bioremediation, the use of microbes to remove and degrade contaminants is considered a biotechnological approach to clean up polluted environments. AIM: The aim of this study was to evaluate the ability of Serratia marcescens in Pb, Cd and Cr removal and the potential use of these bacteria in toxic metal bioremediation from polluted environments. METHODS: A short-term study (120 min) was carried out to study the bacterial growth in the presence of sub-inhibitory concentrations of each metal analysed and the kinetics of metal biosorption in S. marcescens strain. In addition, metal influence on the biosynthesis of the red pigment ‘prodigiosina’ by S. marcescens was monitored. RESULTS: The results obtained in this study show metals biosorption by S. marcescens (range: 0.0133–0.213 μg/g for Pb; 0.097–0.1853 μg/g for Cd; and 0.105–0.176 μg/g for Cr) and confirm the possible use of this bacterium to realize bioremediation processes, especially for Pb removal, and as a bioindicator of metal pollution.
Show more [+] Less [-]Fine and ultrafine particles emitted from laser printers as indoor air contaminants in German offices
2012
Tang, Tao | Hurraß, Julia | Gminski, Richard | Mersch-Sundermann, Volker
PURPOSE: Various publications indicate that the operation of laser printers and photocopiers may be associated with health effects due to the release of gaseous components and fine and ultrafine particles (UFP). However, only sparse studies are available that evaluate the possible exposure of office workers to printer emissions under real conditions. Therefore, the aim of our study was to assess the exposure of office workers to particulate matter released from laser printers and photocopiers. METHODS: Concentrations of fine particles and UFP were measured before, during, and after the operation of laser printing devices in 63 office rooms throughout Germany. Additionally, the particles were characterized by electron microscopy and energy-dispersive X-ray spectroscopy. RESULTS: A significant increase of fine particles and UFP was identified in ambient workplace air during and after the printing processes. Particle fractions between 0.23 and 20 μm emitted by the office machines significantly affect particle mass concentrations while printing 500 pages, i.e., during the printing process, PM0.23–20, PM2.5, and PM10 concentrations increased in 43 out of the evaluated 62 office rooms investigated. Additionally, a significant increase was observed in submicrometer particles, with median particle number concentrations of 6,503 particles/cm3 before and 18,060 particles/cm3 during the printing process. CONCLUSIONS: Our data indicate that laser printers and photocopiers could be a relevant source of fine particles and particularly UFP in office rooms.
Show more [+] Less [-]Large-scale spatial pollution patterns around the North Sea indicated by coastal bird eggs within an EcoQO programme
2012
Dittmann, Tobias | Becker, Peter H. | Bakker, Joop | Bignert, Anders | Nyberg, Elisabeth | Pereira, M Glória | Pijanowska, Ursula | Shore, Richard F. | Stienen, Eric | Toft, Geir Olav | Marencic, Harald
To categorize the marine environmental health status, the Oslo and Paris commissions have recently formulated Ecological Quality Objectives (EcoQOs) for many ecological features including the contamination of coastal bird eggs with mercury and organochlorines. In this study, we describe spatial and temporal patterns of egg contamination around the North Sea and compared them to the EcoQOs. Concentrations of mercury, polychlorinated biphenyl (ΣPCB) congeners, dichlorodiphenyltrichloroethane (ΣDDT) and derivatives, hexachlorobenzene (HCB) and hexachlorocyclohexane (ΣHCH) isomers were analysed in two tern species (Sterna hirundo and Sterna paradisaea) and Oystercatcher (Haematopus ostralegus) eggs collected between 2008 and 2010 in a total of 21 sites in seven countries surrounding the North Sea. Hg, ΣPCB and HCB were highest in the southern sites, while ΣDDT and ΣHCH concentrations were greatest in eggs from the western North Sea and the Elbe estuary. There were rarely any consistent decreases over time for any compounds. In the terns, Hg, HCB and ΣHCH increased at most sites, ΣPCB and ΣDDT in Sweden and Norway. In the Oystercatcher, HCB and ΣHCH increased at more than the half of the sites, ΣPCB, ΣDDT and Hg at several German sites. In the terns, Hg, ΣPCB and ΣDDT exceeded the EcoQO in all, HCB in most years and sites. At most sites, ΣHCH fulfilled the EcoQO in some study years. In the Oystercatcher, Hg, ΣPCB and ΣDDT exceeded the EcoQO in all or most years and sites. HCB and ΣHCH fulfilled the EcoQO in some or all years at most sites. The EcoQO was exceeded most frequently in estuaries. We conclude that EcoQOs are suitable for drawing contamination patterns of the coastal North Sea in an easily understandable manner, offering the opportunity to harmonize the EcoQOs with coordinated environmental monitoring programmes.
Show more [+] Less [-]Biosorption of strontium from aqueous solution by fungus Aspergillus terreus
2012
Khani, M. H. | Pahlavanzadeh, H. | Alizadeh, K.
INTRODUCTION: The biosorption characteristics of strontium ions using fungus Aspergillus terreus were investigated. Experimental parameters affecting the biosorption process such as pH, contact time, initial metal concentration, and temperature were studied. MATHEMATICAL DESCRIPTION: Fungus A. terreus exhibited the highest strontium uptake capacity at 15°C at an initial strontium ion concentration of 876 mg L−1 and an initial pH of 9. Biosorption capacity increased from 219 to 308 mg g−1 with a decrease in temperature from 45°C to 15°C at this initial strontium concentration. The equilibrium data fitted very well to the Langmuir adsorption model in the concentration range of strontium ions and at all the temperatures studied. CONCLUSION: Evaluation of the experimental data in terms of biosorption dynamics showed that the biosorption of strontium onto fungus followed the pseudo-second-order dynamics well (R2 > 0.985). The calculated thermodynamics parameters (−1.64 < ∆G° < −1.93 kJ mol−1 at temperatures of 45–15°C, ∆H° = −4.83 kJ mol−1 and ∆S° = −0.01 kJ mol−1 K−1) showed that the biosorption of strontium ions were feasible, spontaneous, and exothermic at the temperature ranges of 15–45°C.
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