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Aquatic oil spill cleanup using natural sorbents Full text
2015
Paulauskienė, Tatjana | Jucikė, Indrė
One of the most popular transportation methods of crude oil is water transport, leading to potential spills of these pollutants in the seas and oceans and water areas of ports, during their extraction, transportation, transhipment and use. The growth of the Lithuanian economy and the expansion of competitiveness were hardly imagined without the development of the Klaipeda seaport. However, the intensity of shipping and the increase in cargo loading volumes at specialised terminals are associated with a higher risk of environmental pollution. To achieve a sustainable development of the seaport, it is necessary not only to ensure the prevention of potential water pollution but also, if necessary, to use environmentally friendly technology for pollution management. The work analyses the possibilities related to the collection of oil products from the water surface using natural sorbents (peat, wool, moss and straw) and their composites.The research of absorbed amount of crude oil and diesel fuel spilled on the water surface, while using sorbents and their composites, determined that sorbents’ composite straw-peat (composition percentage of straw-peat 25–75 %) absorbs the major amount of both crude oil (60 % of the spilled volume) and diesel fuel (69 % of the spilled volume) comparing to single sorbents and sorbents’ composite straw-peat (composition percentage of straw-peat 50–50 %).
Show more [+] Less [-]Winter time chemical characteristics of aerosols over the Bay of Bengal: continental influence Full text
2015
Aryasree, S. | Nair, Prabha R. | Girach, I. A. | Jacob, Salu
As part of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) conducted under the Geosphere Biosphere Programme of Indian Space Research Organisation, ship-based aerosol sampling was carried out over the marine environment of Bay of Bengal (BoB) during the northern winter months of December 2008 to January 2009. About 101 aerosol samples were collected, covering the region from 3.4° to 21° N latitude and 76° to 98° E longitude—the largest area covered—including the south east (SE) BoB for the first time. These samples were subjected to gravimetric and chemical analysis and the total aerosol loading as well the mass concentration of the ionic species namely F⁻, Cl⁻, Br⁻, NO₂ ⁻, NO₃ ⁻, PO₄ ²⁻, SO₄ ²⁻, NH₄ ⁺, etc. and the metallic species, Na, Mg, Ca, K, Al, Fe, Mn, Zn, and Pb were estimated for each sample. Based on the spatial distribution of individual chemical species, the air flow pattern, and airmass back trajectory analysis, the source characteristics of aerosols for different regions of BoB were identified. Significant level of continental pollution was noticed over BoB during winter. While transport of pollution from Indo-Gangetic Plain (IGP) contributed to aerosols over north BoB, those over SE BoB were influenced by SE Asia. A quantitative study on the wind-induced production of sea salt aerosols and a case study on the species dependent effect of rainfall are also presented in this paper.
Show more [+] Less [-]Effect of Zn stresses on physiology, growth, Zn accumulation, and chlorophyll of Phyllostachys pubescen s Full text
2015
Peng, Danli | Shafi, Mian M. | Wang, Ying | Li, Song | Yan, Wenbo | Chen, Junren | Ye, Zhengqian | Liu, Dan
The effects of Zinc (Zn) on lipid peroxidation, antioxidative enzymes, growth, Zn accumulation, and leaf chlorophyll of Phyllostachys pubescens (Pradelle) Mazel ex J.Houz. were investigated in two greenhouse experiments. Hydroponics experiment with Zn application of 0, 20, 100, and 400 μM revealed that lower concentration of Zn in solution led to increased malondialdehyde (MDA) and proline contents but inhibited SOD activity in all treatments. P. pubescens had showed strong ability to accumulate Zn in stems and reached maximum level at 100 μM with 7.91-fold increase compared with control. In pot experiment, treatment with Zn ranged from 0, 200, 400, 800, 1,600, to 3,200 mg kg⁻¹. Application of 800 mg kg⁻¹ revealed 116, 24.6, and 28.3 times increase in Zn concentration of roots, stems, and leaves, respectively. Growth and chlorophyll contents of plants in pots were better promoted at 400 mg kg⁻¹ Zn, with 60.5 and 30.9 % enhanced roots and shoot compared with control. The bioaccumulation factor (BAF) was in the sequence of stem > roots > leaves. The translocation factor (TF) of stem was higher than leaves.
Show more [+] Less [-]Isotherm, kinetic, and thermodynamic studies on Hg(II) adsorption from aqueous solution by silica- multiwall carbon nanotubes Full text
2015
Saleh, Tawfik A.
Silica combined with 2 % multiwall carbon nanotubes (SiO₂-CNT) was synthesized and characterized. Its sorption efficacy was investigated for the Hg(II) removal from an aqueous solution. The effect of pH on the percentage removal by the prepared material was examined in the range from 3 to 7. The adsorption kinetics were well fitted by using a pseudo-second-order model at various initial Hg(II) concentrations with R ² of >0.99. The experimental data were plotted using the interparticle diffusion model, which indicated that the interparticle diffusion is not the only rate-limiting step. The data is well described by the Freundlich isotherm equation. The activation energy (Ea) for adsorption was 12.7 kJ mol⁻¹, indicating the process is to be physisorption. Consistent with an endothermic process, an increase in the temperature resulted in increasing mercury removal with a ∆Hᵒ of 13.3 kJ/mol and a ∆Sᵒ 67.5 J/mol K. The experimental results demonstrate that the combining of silica and nanotubes is a promising alternative material, which can be used to remove the mercury from wastewaters.
Show more [+] Less [-]Succulent species differ substantially in their tolerance and phytoextraction potential when grown in the presence of Cd, Cr, Cu, Mn, Ni, Pb, and Zn Full text
2015
Zhang, Chengjun | Sale, Peter W. G. | Clark, Gary J | Liu, Wuxing | Doronila, Augustine I. | Kolev, Spas D. | Tang, Caixian
Plants for the phytoextraction of heavy metals should have the ability to accumulate high concentrations of such metals and exhibit multiple tolerance traits to cope with adverse conditions such as coexistence of multiple heavy metals, high salinity, and drought which are the characteristics of many contaminated soils. This study compared 14 succulent species for their phytoextraction potential of Cd, Cr, Cu, Mn, Ni, Pb, and Zn. There were species variations in metal tolerance and accumulation. Among the 14 succulent species, an Australian native halophyte Carpobrotus rossii exhibited the highest relative growth rate (20.6–26.6 mg plant⁻¹ day⁻¹) and highest tolerance index (78–93 %), whilst Sedum “Autumn Joy” had the lowest relative growth rate (8.3–13.6 mg plant⁻¹ day⁻¹), and Crassula multicava showed the lowest tolerance indices (<50 %). Carpobrotus rossii and Crassula helmsii showed higher potential for phytoextraction of these heavy metals than other species. These findings suggest that Carpobrotus rossii is a promising candidate for phytoextraction of multiple heavy metals, and the aquatic or semiterrestrial Crassula helmsii is suitable for phytoextraction of Cd and Zn from polluted waters or wetlands.
Show more [+] Less [-]Induction of reactive oxygen species in marine phytoplankton under crude oil exposure Full text
2015
Ozhan, Koray | Zahraeifard, Sara | Smith, Aaron P. | Bargu, Sibel
Exposure of phytoplankton to the water-accommodated fraction of crude oil can elicit a number of stress responses, but the mechanisms that drive these responses are unclear. South Louisiana crude oil was selected to investigate its effects on population growth, chlorophyll a (Chl a) content, antioxidative defense, and lipid peroxidation, for the marine diatom, Ditylum brightwellii, and the dinoflagellate, Heterocapsa triquetra, in laboratory-based microcosm experiments. The transcript levels of several possible stress-responsive genes in D. brightwellii were also measured. The microalgae were exposed to crude oil for up to 96 h, and Chl a content, superoxide dismutase (SOD), the glutathione pool (GSH and GSSG), and lipid peroxidation content were analyzed. The cell growth of both phytoplankton species was inhibited with increasing crude oil concentrations. Crude oil exposure did not affect Chl a content significantly in cells. SOD activities showed similar responses in both species, being enhanced at 4- and 8-mg/L crude oil exposure. Only H. triquetra demonstrated enhanced activity in GSSG pool and lipid peroxidation at 8-mg/L crude oil exposure, suggesting that phytoplankton species have distinct physiological responses and tolerance levels to crude oil exposure. This study indicated the activation of reactive oxygen species (ROS) in phytoplankton under crude oil exposure; however, the progressive damage in cells is still unknown. Thus, ROS-related damage in nucleic acid, lipids, proteins, and DNA, due to crude oil exposure could be a worthwhile subject of study to better understand crude oil toxicity at the base of the food web.
Show more [+] Less [-]Mercury heavy-metal-induced physiochemical changes and genotoxic alterations in water hyacinths [Eichhornia crassipes (Mart.)] Full text
2015
Malar, Srinivasan | Sahi, Shivendra Vikram | Favas, Paulo J. C. | Venkatachalam, Perumal
Mercury heavy metal pollution has become an important environmental problem worldwide. Accumulation of mercury ions by plants may disrupt many cellular functions and block normal growth and development. To assess mercury heavy metal toxicity, we performed an experiment focusing on the responses of Eichhornia crassipes to mercury-induced oxidative stress. E. crassipes seedlings were exposed to varying concentrations of mercury to investigate the level of mercury ions accumulation, changes in growth patterns, antioxidant defense mechanisms, and DNA damage under hydroponics system. Results showed that plant growth rate was significantly inhibited (52 %) at 50 mg/L treatment. Accumulation of mercury ion level were 1.99 mg/g dry weight, 1.74 mg/g dry weight, and 1.39 mg/g dry weight in root, leaf, and petiole tissues, respectively. There was a decreasing trend for chlorophyll a, b, and carotenoids with increasing the concentration of mercury ions. Both the ascorbate peroxidase and malondialdehyde contents showed increased trend in leaves and roots up to 30 mg/L mercury treatment and slightly decreased at the higher concentrations. There was a positive correlation between heavy metal dose and superoxide dismutase, catalase, and peroxidase antioxidative enzyme activities which could be used as biomarkers to monitor pollution in E. crassipes. Due to heavy metal stress, some of the normal DNA bands were disappeared and additional bands were amplified compared to the control in the random amplified polymorphic DNA (RAPD) profile. Random amplified polymorphic DNA results indicated that genomic template stability was significantly affected by mercury heavy metal treatment. We concluded that DNA changes determined by random amplified polymorphic DNA assay evolved a useful molecular marker for detection of genotoxic effects of mercury heavy metal contamination in plant species.
Show more [+] Less [-]Influence of pH, inorganic anions, and dissolved organic matter on the photolysis of antimicrobial triclocarban in aqueous systems under simulated sunlight irradiation Full text
2015
Ding, Shi-Ling | Wang, Xi-Kui | Jiang, Wen-Qiang | Zhao, Ru-Song | Shen, Ting-Ting | Wang, Chen | Wang, Xia
The photolysis of the antimicrobial triclocarban (TCC) in aqueous systems under simulated sunlight irradiation was studied. The effects of several abiotic parameters, including solution pH, initial TCC concentration, presence of natural organic matter, and most common inorganic anions in surface waters, were investigated. The results show that the photolysis of TCC followed pseudo-first-order kinetics. The TCC photolysis rate constant increased with increasing solution pH and decreasing the initial TCC concentration. Compared with the TCC photolysis in pure water, the presence of aqueous bicarbonate, nitrate, humic acids, and its sodium salt decreased the TCC photolysis rate, but fulvic acid increased the TCC photolysis rate. The electron spin resonance and reactive oxygen species scavenging experiments indicated that TCC may undergo two different types of phototransformation reactions: direct photolysis and energy transfer to generate¹O₂. The main degradation products were tentatively identified by gas chromatography interfaced with mass spectrometry (GC-MS), and a possible degradation pathway was also proposed.
Show more [+] Less [-]Remediation of cadmium- and lead-contaminated agricultural soil by composite washing with chlorides and citric acid Full text
2015
Li, Yu-jiao | Hu, Peng-jie | Zhao, Jie | Dong, Chang-xun
Composite washing of cadmium (Cd)- and lead (Pb)-contaminated agricultural soil from Hunan province in China using mixtures of chlorides (FeCl₃, CaCl₂) and citric acid (CA) was investigated. The concentrations of composite washing agents for metal removal were optimized. Sequential extraction was conducted to study the changes in metal fractions after soil washing. The removal of two metals at optimum concentration was reached. Using FeCl₃mixed with CA, 44 % of Cd and 23 % of Pb were removed, and 49 and 32 % by CaCl₂mixed with CA, respectively. The mechanism of composite washing was postulated. A mixture of chlorides and CA enhanced metal extraction from soil through the formation of metal–chloride and metal–citrate complexes. CA in extract solutions promoted the formation of metal–chloride complexes and reduced the solution pH. Composite washing reduced Cd and Pb in Fe–Mn oxide forms significantly. Chlorides and CA exerted a synergistic effect on metal extraction during composite washing.
Show more [+] Less [-]Perfluoroalkyl and polyfluoroalkyl substances in consumer products Full text
2015
Kotthoff, Matthias | Müller, Josef | Jürling, Heinrich | Schlummer, Martin | Fiedler, Dominik
Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are used in a wide range of products of all day life. Due to their toxicological potential, an emerging focus is directed towards their exposure to humans. This study investigated the PFAS load of consumer products in a broad perspective. Perfluoroalkyl sulfonic acids (C₄, C₆–C₈, C₁₀-PFSA), carboxylic acids (C₄–C₁₄-PFCA) and fluorotelomer alcohols (4:2, 6:2; 8:2 and 10:2 FTOH) were analysed in 115 random samples of consumer products including textiles (outdoor materials), carpets, cleaning and impregnating agents, leather samples, baking and sandwich papers, paper baking forms and ski waxes. PFCA and PFSA were analysed by HPLC-MS/MS, whereas FTOH were detected by GC/CI-MS. Consumer products such as cleaning agents or some baking and sandwich papers show low or negligible PFSA and PFCA contents. On the other hand, high PFAS levels were identified in ski waxes (up to about 2000 μg/kg PFOA), leather samples (up to about 200 μg/kg PFBA and 120 μg/kg PFBS), outdoor textiles (up to 19 μg/m² PFOA) and some other baking papers (up to 15 μg/m² PFOA). Moreover, some test samples like carpet and leather samples and outdoor materials exceeded the EU regulatory threshold value for PFOS (1 μg/m²). A diverse mixture of PFASs can be found in consumer products for all fields of daily use in varying concentrations. This study proves the importance of screening and monitoring of consumer products for PFAS loads and the necessity for an action to regulate the use of PFASs, especially PFOA, in consumer products.
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