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Evaluation of PCDD/F pollution in surface sediments of Izmit Bay Полный текст
2013
Karademir, Aykan | Ergül, Halim Aytekin | Telli, Bircan | Kılavuz, Seda Aslan | Terzi, Mine
This study evaluates PCDD/F pollution in the surface sediments of Izmit Bay (Turkey) and assesses the possible sources of PCDD/F inputs to the bay. The results showed that concentrations of toxic PCDD/F congeners in the sediments varied between 0.45 and 255 ng WHO2005-TEQ/kg dry weight. Pollution mapping shows that PCDD/F levels in the central section of Izmit Bay are much higher than those in the eastern and the western sections. Sediments collected from the northern part of the central section showed very high PCDD/F concentrations. The samples reveal three different congener profiles dominated by OCDF, 1,2,3,4,6,7,8-HpCDF, and OCDD respectively. The dominance of OCDF in the sediment samples taken from the central section was attributed to the former production of vinyl chloride monomer in the area, while that of 1,2,3,4,6,7,8-HpCDF was attributed to the (previously unknown) use of a chlorophenol-based fungicide in the region. The OCDD dominated group was explained by the use of pentachlorophenol. The results indicate that historic industrial discharges are the main contributor to the PCDD/F pollution in the sediments.
Показать больше [+] Меньше [-]Water quality modelling of Lis River, Portugal Полный текст
2013
Vieira, Judite | Fonseca, André | Vilar, Vítor J. P. | Boaventura, Rui A. R. | Botelho, Cidália M. S.
The aim of the study was to predict the impact of flow conditions, discharges and tributaries on the water quality of Lis River using QUAL2Kw model. Calibration of the model was performed, based on data obtained in field surveys carried out in July 2004 and November 2006. Generally the model fitted quite well the experimental data. The results indicated a decrease of water quality in the downstream area of Lis River, after the confluence of Lena, Milagres and Amor tributaries, as a result of discharges of wastewaters containing degradable organics, nutrients and pathogenic organisms from cattle-raising wastewaters, domestic effluents and agricultural runoff. The water quality criteria were exceeded in these areas for dissolved oxygen, biochemical oxygen demand, total nitrogen and faecal coliforms. Water quality modelling in different scenarios showed that the impact of tributaries on the quality of Lis River water was quite negligible and mainly depends on discharges, which are responsible by an increase of almost 45, 13 and 44 % of ultimate carbonaceous biochemical oxygen demand (CBODᵤ), ammonium nitrogen and faecal coliforms, for winter simulation, and 23, 33 and 36 % for summer simulation, respectively, when compared to the real case scenario.
Показать больше [+] Меньше [-]Competitive biosorption of lead, cadmium, copper, and arsenic ions using algae Полный текст
2013
Sulaymon, Abbas H. | Mohammed, Ahmed A. | Al-Musawi, Tariq J.
The present study aims to evaluate the competitive biosorption of lead, cadmium, copper, and arsenic ions by using native algae. A series of experiments were carried out in a batch reactor to obtain equilibrium data for adsorption of single, binary, ternary, and quaternary metal solutions. The biosorption of these metals is based on ion exchange mechanism accompanied by the release of light metals such as calcium, magnesium, and sodium. Experimental parameters such as pH, initial metal concentrations, and temperature were studied. The optimum pH found for removal were 5 for Cd²⁺ and As³⁺ and 3 and 4 for Pb²⁺ and Cu²⁺, respectively. Fourier transformation infrared spectroscopy analysis was used to find the effects of functional groups of algae in biosorption process. The results showed that Pb²⁺ made a greater change in the functional groups of algal biomass due to high affinity to this metal. An ion exchange model was found suitable for describing the biosorption process. The affinity constants sequence calculated for single system was K Pb > K Cᵤ > K Cd > K Aₛ; these values reduced in binary, ternary, and quaternary systems. In addition, the experimental data showed that the biosorption of the four metals fitted well the pseudo-second-order kinetics model.
Показать больше [+] Меньше [-]Heavy metal accumulation by poplar in calcareous soil with various degrees of multi-metal contamination: implications for phytoextraction and phytostabilization Полный текст
2013
Hu, Yahu | Nan, Zhongren | Su, Jieqiong | Wang, Ning
The object of this study was to assess the capacity of Populus alba L. var. pyramidalis Bunge for phytoremediation of heavy metals on calcareous soils contaminated with multiple metals. In a pot culture experiment, a multi-metal-contaminated calcareous soil was mixed at different ratios with an uncontaminated, but otherwise similar soil, to establish a gradient of soil metal contamination levels. In a field experiment, poplars with different stand ages (3, 5, and 7 years) were sampled randomly in a wastewater-irrigated field. The concentrations of cadmium (Cd), Cu, lead (Pb), and zinc (Zn) in the poplar tissues and soil were determined. The accumulation of Cd and Zn was greatest in the leaves of P. pyramidalis, while Cu and Pb mainly accumulated in the roots. In the pot experiment, the highest tissue concentrations of Cd (40.76 mg kg(-1)), Cu (8.21 mg kg(-1)), Pb (41.62 mg kg(-1)), and Zn (696 mg kg(-1)) were all noted in the multi-metal-contaminated soil. Although extremely high levels of Cd and Zn accumulated in the leaves, phytoextraction using P. pyramidalis may take at least 24 and 16 years for Cd and Zn, respectively. The foliar concentrations of Cu and Pb were always within the normal ranges and were never higher than 8 and 5 mg kg(-1), respectively. The field experiment also revealed that the concentrations of all four metals in the bark were significantly higher than that in the wood. In addition, the tissue metal concentrations, together with the NH4NO3-extractable concentrations of metals in the root zone, decreased as the stand age increased. P. pyramidalis is suitable for phytostabilization of calcareous soils contaminated with multiple metals, but collection of the litter fall would be necessary due to the relatively high foliar concentrations of Cd and Zn.
Показать больше [+] Меньше [-]Population characteristics of young African women influencing prenatal exposure to DDT (Manhiça, Mozambique) Полный текст
2013
Manaca, Maria N. | Grimalt, Joan O. | Sunyer, Jordi | Guinovart, Caterina | Sacarlal, Jahit | Menendez, Clara | Alonso, Pedro L. | Dobaño, Carlota
Population characteristics of young African women influencing prenatal exposure to DDT (Manhiça, Mozambique) Полный текст
2013
Manaca, Maria N. | Grimalt, Joan O. | Sunyer, Jordi | Guinovart, Caterina | Sacarlal, Jahit | Menendez, Clara | Alonso, Pedro L. | Dobaño, Carlota
The concentrations of dichlorodiphenyltrichloroethane (DDT) compounds in cord blood of 214 children born between 2003 and 2006 in Manhiça (Mozambique) have been determined. In this time interval, corresponding to the period before DDT reintroduction for indoor residual spraying, the observed values averaged 0.8 and 0.4 ng/ml for 4,4′-dichlorodiphenyldichloroethylene (4,4′-DDE) and 4,4′-DDT, respectively, and were similar to those found in western countries. However, the 4,4′-DDT/4,4′-DDE ratio was high indicating that the inputs of these compounds arriving to children in utero originated from recent uses of the insecticide. The strongest factor affecting DDT concentration was parity. A well-defined decreasing concentration trend was observed for the cord blood concentrations in the period of study. The trend was also observed for multiparae and primiparae mothers independently. Children from multiparae women showed much lower concentrations than primiparae women. Children from mothers with secondary school level exhibited lower concentrations of these pesticides than mothers with lower degree of education.
Показать больше [+] Меньше [-]Population characteristics of young African women influencing prenatal exposure to DDT (Manhiça, Mozambique) Полный текст
2013
Manaca, María N. | Grimalt, Joan O. | Sunyer, Jordi | Guinovart, Caterina | Sacarlal, Jahit | Menéndez, Clara | Alonso, Pedro L. | Dobaño, Carlota
The concentrations of dichlorodiphenyltrichloroethane (DDT) compounds in cord blood of 214 children born between 2003 and 2006 in Manhiça (Mozambique) have been determined. In this time interval, corresponding to the period before DDT reintroduction for indoor residual spraying, the observed values averaged 0.8 and 0.4 ng/ml for 4,4′-dichlorodiphenyldichloroethylene (4,4′-DDE) and 4,4′-DDT, respectively, and were similar to those found in western countries. However, the 4,4′-DDT/4,4′-DDE ratio was high indicating that the inputs of these compounds arriving to children in utero originated from recent uses of the insecticide. The strongest factor affecting DDT concentration was parity. A well-defined decreasing concentration trend was observed for the cord blood concentrations in the period of study. The trend was also observed for multiparae and primiparae mothers independently. Children from multiparae women showed much lower concentrations than primiparae women. Children from mothers with secondary school level exhibited lower concentrations of these pesticides than mothers with lower degree of education. | We thank all the families for their participation in the study and the staff of the Manhiça Health Research Center for their support during data and cord blood sample collection, particularly Cleofé Romagosa and Azucena Bardají. MNM is funded by a Ph.D. Scholarship from Fundació Marfà, CD is supported by the Spanish Ministry of Science and Innovation (MICINN; RYC-2008-02631), and CG was supported by the Spanish Ministry of Health (Fondo de Investigaciones Sanitarias, Instituto de Salud Carlos III; CM04/00028). Funding was received from MICINN (INMA G03/176, Consolider Ingenio GRACCIE, CSD2007-00067), CSIC (PIF06-053), and ArcRisk EU Project (FP7-ENV-2008-1-226534). The CISM receives core support from the Spanish Agency for International Cooperation and Development (AECID). This paper was also sponsored by research group 2009SGR1178 from Generalitat de Catalunya. | Peer reviewed
Показать больше [+] Меньше [-]Solar photocatalysis for treatment of Acid Yellow-17 (AY-17) dye contaminated water using Ag@TiO₂ core–shell structured nanoparticles Полный текст
2013
Wastewater released from textile industries causes water pollution, and it needs to be treated before discharge to the environment by cost effective technologies. Solar photocatalysis is a promising technology for the treatment of dye wastewater. The Ag@TiO nanoparticles comprising of Ag core and TiO shell (Ag@TiO) have unique photocatalytic property of inhibition of electron-hole recombination and visible light absorption, which makes it a promising photocatalyst for use in solar photocatalysis and with higher photocatalytic rate. Therefore, in the present work, the Ag@TiO nanoparticles synthesized by one pot method with postcalcination step has been used for the degradation of Acid Yellow-17 (AY-17) dye under solar light irradiation. The Ag@TiO nanoparticles were characterized using thermogravimetric-differential thermal analysis, X-ray diffraction, transmission electron microscopy, selected area electron diffraction, and energy dispersive X-ray analysis. The catalyst has been found to be very effective in solar photocatalysis of AY-17, as compared to other catalysts. The effects of pH, catalyst loading, initial dye concentration, and oxidants on photocatalysis were also studied. The optimized parameters for degradation of AY-17 using Ag@TiO were found to be pH 3, dye/catalyst ratio of 1:10 (g/g), and 2 g/L of (NH)SO as oxidant. Efficient decolorization and mineralization of AY-17 was achieved. The kinetics of color, total organic carbon, and chemical oxygen demand removal followed the Langmuir-Hinshelwood model. Ag@TiO catalyst can be reused thrice without much decline in efficiency. The catalyst exhibited its potential as economic photocatalyst for treatment of dye wastewater.
Показать больше [+] Меньше [-]Core–shell magnetite-silica dithiocarbamate-derivatised particles achieve the Water Framework Directive quality criteria for mercury in surface waters Полный текст
2013
Lopes, C. B. | Figueira, P. | Tavares, D. S. | Lin, Z. | Daniel-da-Silva, A. L. | Duarte, A. C. | Rocha, J. | Trindade, T. | Pereira, E.
Core–shell magnetite-silica dithiocarbamate-derivatised particles achieve the Water Framework Directive quality criteria for mercury in surface waters Полный текст
2013
Lopes, C. B. | Figueira, P. | Tavares, D. S. | Lin, Z. | Daniel-da-Silva, A. L. | Duarte, A. C. | Rocha, J. | Trindade, T. | Pereira, E.
The sorption capacity of nanoporous titanosilicate Engelhard titanosilicate number 4 (ETS-4) and silica-coated magnetite particles derivatised with dithiocarbamate groups towards Hg(II) was evaluated and compared in spiked ultra-pure and spiked surface-river water, for different batch factors. In the former, and using a batch factor of 100 m(3)/kg and an initial Hg(II) concentrations matching the maximum allowed concentration in an effluent discharge, both materials achieve Hg(II) uptake efficiencies in excess of 99 % and a residual metal concentration lower than the guideline value for drinking water quality. For the surface-river water and the same initial concentration, the Hg(II) uptake efficiency of magnetite particles is outstanding, achieving the quality criteria established by the Water Framework Directive (concerning Hg concentration in surface waters) using a batch factor of 50 m(3)/kg, while the efficiency of ETS-4 is significantly inferior. The dissimilar sorbents' Hg(II) removal efficiency is attributed to different uptake mechanisms. This study also highlights the importance of assessing the effective capacity of the sorbents under realistic conditions in order to achieve trustable results.
Показать больше [+] Меньше [-]Core-shell magnetite-silica dithiocarbamate-derivatised particles achieve the Water Framework Directive quality criteria for mercury in surface waters Полный текст
1000 | 2013
Lopes, C. B. | Figueira, P. | Tavares, D. S. | Lin, Z. | Daniel-da-Silva, A. L. | Duarte, A. C. | Rocha, J. | Trindade, T. | Pereira, E.
The sorption capacity of nanoporous titanosilicate Engelhard titanosilicate number 4 (ETS-4) and silica-coated magnetite particles derivatised with dithiocarbamate groups towards Hg(II) was evaluated and compared in spiked ultra-pure and spiked surface-river water, for different batch factors. In the former, and using a batch factor of 100 m(3)/kg and an initial Hg(II) concentrations matching the maximum allowed concentration in an effluent discharge, both materials achieve Hg(II) uptake efficiencies in excess of 99 % and a residual metal concentration lower than the guideline value for drinking water quality. For the surface-river water and the same initial concentration, the Hg(II) uptake efficiency of magnetite particles is outstanding, achieving the quality criteria established by the Water Framework Directive (concerning Hg concentration in surface waters) using a batch factor of 50 m(3)/kg, while the efficiency of ETS-4 is significantly inferior. The dissimilar sorbents' Hg(II) removal efficiency is attributed to different uptake mechanisms. This study also highlights the importance of assessing the effective capacity of the sorbents under realistic conditions in order to achieve trustable results.
Показать больше [+] Меньше [-]An assessment of dioxin contamination from the intermittent operation of a municipal waste incinerator in Japan and associated remediation Полный текст
2013
Takeda, Nobuo | Takaoka, Masaki
Significant dioxin (polychlorinated dibenzo-para-dioxins (PCDDs)/polychlorinated dibenzo-furans (PCDFs)) pollution from a municipal solid waste incinerator was discovered in 1997 in Osaka prefecture/Japan. The cause and mechanism of pollution was identified by a detailed assessment of the environment and incinerator plant. The primary sources of PCDD/PCDF pollution were high dioxin releases from an intermittently operated waste incinerator with PCDD/PCDF emissions of 150 ng-TEQ/Nm³. PCDD/PCDF also accumulated in the wet scrubber system (3,000 μg TEQ/L) by adsorption and water recirculation in the incinerator. Scrubber water was air-cooled with a cooling tower located on the roof of the incinerator. High concentrations of dioxins in the cooling water were released as aerosols into the surrounding and caused heavy soil pollution in the area near the plant. These emissions were considered as the major contamination pathway from the plant. Decontamination and soil remediation in and around the incinerator plant were conducted using a variety of destruction technologies (including incineration, photochemical degradation and GeoMelt technology). Although the soil remediation process was successfully finished in December 2006 about 3 % of the waste still remains. The case demonstrates that releases from incinerators which do not use best available technology or which are not operated according to best environmental practices can contaminate their operators and surrounding land. This significant pollution had a large impact on the Japanese government’s approach toward controlling dioxin pollution. Since this incident, a ministerial conference on dioxins has successfully strengthened control measures.
Показать больше [+] Меньше [-]Photocatalytic degradation of chlorophenols in soil washing wastes containing Brij 35. Correlation between the degradation kinetics and the pollutants–micelle binding Полный текст
2013
Davezza, M. | Fabbri, Donata | Pramauro, E. | Prevot, A Bianco
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.
Показать больше [+] Меньше [-]Synthesising acid mine drainage to maintain and exploit indigenous mining micro-algae and microbial assemblies for biotreatment investigations Полный текст
2013
Orandi, Sanaz | Lewis, David M.
Synthesising acid mine drainage to maintain and exploit indigenous mining micro-algae and microbial assemblies for biotreatment investigations Полный текст
2013
Orandi, Sanaz | Lewis, David M.
The stringent regulations for discharging acid mine drainage (AMD) has led to increased attention on traditional or emerging treatment technologies to establish efficient and sustainable management for mine effluents. To assess new technologies, laboratory investigations on AMD treatment are necessary requiring a consistent supply of AMD with a stable composition, thus limiting environmental variability and uncertainty during controlled experiments. Additionally, biotreatment systems using live cells, particularly micro-algae, require appropriate nutrient availability. Synthetic AMD (Syn-AMD) meets these requirements. However, to date, most of the reported Syn-AMDs are composed of only a few selected heavy metals without considering the complexity of actual AMD. In this study, AMD was synthesised based on the typical AMD characteristics from a copper mine where biotreatment is being considered using indigenous AMD algal-microbes. Major cations (Ca, Na, Cu, Zn, Mg, Mn and Ni), trace metals (Al, Fe, Ag, Na, Co, Mo, Pb and Cr), essential nutrients (N, P and C) and high SO₄ were incorporated into the Syn-AMD. This paper presents the preparation of chemically complex Syn-AMD and the challenges associated with combining metal salts of varying solubility that is not restricted to one particular mine site. The general approach reported and the particular reagents used can produce alternative Syn-AMD with varying compositions. The successful growth of indigenous AMD algal-microbes in the Syn-AMD demonstrated its applicability as appropriate generic media for cultivation and maintenance of mining microorganisms for future biotreatment studies.
Показать больше [+] Меньше [-]Synthesising acid mine drainage to maintain and exploit indigenous mining micro-algae and microbial assemblies for biotreatment investigations Полный текст
2013
Orandi, S. | Lewis, D.
The stringent regulations for discharging acid mine drainage (AMD) has led to increased attention on traditional or emerging treatment technologies to establish efficient and sustainable management for mine effluents. To assess new technologies, laboratory investigations on AMD treatment are necessary requiring a consistent supply of AMD with a stable composition, thus limiting environmental variability and uncertainty during controlled experiments. Additionally, biotreatment systems using live cells, particularly micro-algae, require appropriate nutrient availability. Synthetic AMD (Syn-AMD) meets these requirements. However, to date, most of the reported Syn-AMDs are composed of only a few selected heavy metals without considering the complexity of actual AMD. In this study, AMD was synthesised based on the typical AMD characteristics from a copper mine where biotreatment is being considered using indigenous AMD algal-microbes. Major cations (Ca, Na, Cu, Zn, Mg, Mn and Ni), trace metals (Al, Fe, Ag, Na, Co, Mo, Pb and Cr), essential nutrients (N, P and C) and high SO(4) were incorporated into the Syn-AMD. This paper presents the preparation of chemically complex Syn-AMD and the challenges associated with combining metal salts of varying solubility that is not restricted to one particular mine site. The general approach reported and the particular reagents used can produce alternative Syn-AMD with varying compositions. The successful growth of indigenous AMD algal-microbes in the Syn-AMD demonstrated its applicability as appropriate generic media for cultivation and maintenance of mining microorganisms for future biotreatment studies. | Sanaz Orandi, David M. Lewis
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