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1.
Hany El-Gamal M. El-Azab Farid A. I. Abdel Mageed M. Hasabelnaby Hassanien M. Hassanien 《Environmental science and pollution research international》2013,20(12):8700-8708
The natural radioactivity of soil samples from Assiut city, Egypt, was studied. The activity concentrations of 28 samples were measured with a NaI(Tl) detector. The radioactivity concentrations of 226Ra, 232Th, and 40K showed large variations, so the results were classified into two groups (A and B) to facilitate the interpretation of the results. Group A represents samples collected from different locations in Assiut and characterized by low activity concentrations with average values of 46.15?±?9.69, 30.57?±?4.90, and 553.14?±?23.19 for 226Ra, 232Th, and 40K, respectively. Group B represents samples mainly collected from the area around Assiut Thermal Power Plant and characterized by very high activity concentrations with average values of 3,803?±?145, 1,782?±?98, and 1,377?±?78 for 226Ra, 232Th, and 40K, respectively. In order to evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity (Raeq), the absorbed dose rate (D), the annual effective dose rate (E), the external hazard index (H ex), and the annual gonadal dose equivalent (AGDE) have been calculated and compared with the internationally approved values. For group A, the calculated averages of these parameters are in good agreement with the international recommended values except for the absorbed dose rate and the AGDE values which are slightly higher than the international recommended values. However, for group B, all obtained averages of these parameters are much higher by several orders of magnitude than the international recommended values. The present work provides a background of radioactivity concentrations in the soil of Assiut. 相似文献
2.
Introduction
This study collected long-term airborne lead concentrations in the Korean peninsula and analyzed their temporal, spatial, and cancer risk characterization.Methods
Approximately, 12,000 airborne samples of total suspended particulate (TSP) were collected from 30 ambient air monitoring stations in inland (Daegu, Daejeon, Gwangju, and Seoul) cities and portal cities (Incheon, Busan, and Ulsan) over a period of 7?years (2004?C2010). High volume air samplers were employed to collect daily TSP samples during the second week of the consecutive months throughout the entire study period. The concentrations of Pb extracted from the TSP samples were analyzed using either inductively coupled plasma-atomic emission or flame atomic absorption spectrometry.Results
The long-term high mean Pb concentrations were observed in the port cities including Incheon (88?±?18?ng/m3), Ulsan (61?±?7?ng/m3), and Busan (58?±?6?ng/m3). In the temporal analysis, seasonal mean Pb levels were relatively higher in winter and spring than those in summer and fall. In the spatial analysis, the mean Pb levels in spring, winter, and fall from Incheon, which showed the highest seasonal concentrations except summer, were 110?±?19, 101?±?18, and 76?±?23?ng/m3, respectively. In summer, the highest seasonal mean Pb level was observed in the largest industrial city and the second port city, Ulsan (78?±?15?ng/m3), followed by Incheon (65?±?13?ng/m3).Conclusion
The estimated excess cancer risk analysis showed that inhalation of Pb could result in cancer for one or two persons per million of population in the Korean peninsula. 相似文献3.
Li X Zhou Q Wei S Ren W 《Environmental science and pollution research international》2012,19(5):1773-1780
Purpose
Screening out cadmium (Cd) excluding cultivars of a crop in agricultural production is an effective way to prohibit Cd entering into food chain.Methods
A judging criterion for Cd-excluding cultivars based on food safety was suggested and used in the identification of Cd-excluding welsh onion (Allium fistulosum L.) cultivars. A pot culture experiment was carried out to screen out Cd-excluding cultivars, of which the results were confirmed by plot experiments. The relevant factors of Cd accumulation in the pseudostem were analyzed and used in the correlation analysis aiming to study the low Cd accumulation mechanisms.Results
The concentration of Cd in the pseudostem of welsh onions was 0.08?C0.20, 0.18?C0.41, and 0.26?C0.61?mg/kg fresh weight (FW) under three treatments (1.0, 2.5, and 5.0?mg/kg), respectively. The significant (p?0.05) difference in the concentration of Cd in the pseudostem was observed among 25 welsh onion cultivars, but Cd contamination in soil had little influence on biomass and the contents of soluble sugar, NO 3 ? ?CN, and eight other elements in the tested welsh onion cultivars. Two cultivars were identified as Cd-excluding cultivars, mainly because the accumulation of Cd in their pseudostem was only 0.041?±?0.003 and 0.046?±?0.002?mg/kg FW, and 0.054?±?0.001 and 0.066?±?0.011?mg/kg FW, when growing in plots with Cd concentration of 0.49 and 0.99?mg/kg, respectively.Conclusions
Ribentiegancongwang and Wuyeqi could be identified as Cd-excluding cultivars. Low bioaccumulation factor of the roots was the main mechanism of Cd-excluding welsh onion cultivars. 相似文献4.
Murati M Oturan N Aaron JJ Dirany A Tassin B Zdravkovski Z Oturan MA 《Environmental science and pollution research international》2012,19(5):1563-1573
Introduction
The degradation and mineralization of two triketone (TRK) herbicides, including sulcotrione and mesotrione, by the electro-Fenton process (electro-Fenton using Pt anode (EF-Pt), electro-Fenton with BDD anode (EF-BDD) and anodic oxidation with BDD anode) were investigated in acidic aqueous medium.Methods
The reactivity of both herbicides toward hydroxyl radicals was found to depend on the electron-withdrawing effect of the aromatic chlorine or nitro substituents. The degradation of sulcotrione and mesotrione obeyed apparent first-order reaction kinetics, and their absolute rate constants with hydroxyl radicals at pH?3.0 were determined by the competitive kinetics method.Results and discussion
The hydroxylation absolute rate constant (k abs) values of both TRK herbicides ranged from 8.20?×?108 (sulcotrione) to 1.01?×?109 (mesotrione) L?mol?1?s?1, whereas those of the TRK main cyclic or aromatic by-products, namely cyclohexane 1,3-dione , (2-chloro-4-methylsulphonyl) benzoic acid and 4-(methylsulphonyl)-2-nitrobenzoic acid, comprised between 5.90?×?108 and 3.29?×?109?L?mol?1?s?1. The efficiency of mineralization of aqueous solutions of both TRK herbicides was evaluated in terms of total organic carbon removal. Mineralization yields of about 97?C98% were reached in optimal conditions for a 6-h electro-Fenton treatment time.Conclusions
The mineralization process steps involved the oxidative opening of the aromatic or cyclic TRK by-products, leading to the formation of short-chain carboxylic acids, and, then, of carbon dioxide and inorganic ions. 相似文献5.
Jaiswal M Chauhan D Sankararamakrishnan N 《Environmental science and pollution research international》2012,19(6):2055-2062
Purpose
Removal of malathion from agricultural runoff was studied using novel copper-coated chitosan nanocomposite (CuCH)??a biopolymeric waste obtained from marine industry.Methods
Synthesis and characterization of the adsorbent using different spectral techniques like Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer, Emmett, and Teller surface analyzer have been carried out. Equilibrium studies have been carried out to optimize the dose rate, pH, and the reaction time. Parathion and methyl parathion removal were also evaluated by CuCH in the batch mode. Using gas chromatography?Cmass spectrometry (GC?CMS) and FTIR studies suitable mechanism for adsorption has been suggested.Results
The particle size of the adsorbent ranged from 700 to 750?nm. The surface area was found to be 20?m2?g-1 with a pore volume of 0.11?cc?g-1. The maximum adsorption capacity of malathion by CuCH was found to be 322.6?±?3.5?mg?g-1 at an optimum pH of 2.0. Presence of copper ions enhanced the adsorption capacity of the adsorbent. The reaction was found to follow pseudo second-order kinetics with a rate constant of 0.53?g?mg-1?min-1. Evidence from FTIR indicated that copper ions form a dithionate complex with malathion during the adsorption stage. The adsorbent was found to remove malathion completely from spiked concentration of 2?mg?l-1 in the agricultural run-off samples. It was also found that CuCH removed other organophospurous pesticides like methyl parathion and parathion under prevailing conditions.Conclusions
The results indicated that CuCH could be applied for the removal of organophosphorous pesticides. 相似文献6.
Bakircioglu D 《Environmental science and pollution research international》2012,19(6):2428-2437
Purpose
An online cloud-point extraction (CPE) coupled with flow injection method is developed for the separation and preconcentration of palladium and lead from various matrices using flame atomic absorption spectrometry (FAAS).Method
The method employs the formation of complexes of the metallic species with dimethylglyoxime, which are subsequently entrapped in the micelles of the surfactant Triton X-114, upon increase of the solution temperature to 60°C and loaded into the flow injection system at a flow rate of 4.6?mL?min?1. The surfactant rich-phase was retained in a minicolumn packed with animal wool at pH?6 and eluted with 1.0?mol?L?1 nitric acid in methanol at a flow rate of 1.1?mL?min?1 directly into the nebulizer of the FAAS. The CPE variables and flow injection conditions affecting the analytical performance of the combined methodology was studied and optimized.Results
Under the optimized conditions for 25?mL of preconcentrated solution, the enrichment factors were 51 and 44, and the limit of detections were 1.0 and 1.4?ng?mL?1 for palladium and lead, respectively. Finally, the developed method was applied for the determination of palladium and lead in street dust, soil, radiology waste, catalytic converter, and urban aerosol samples.Conclusions
Cloud-point extraction coupled with flow injection-FAAS was proposed as an effective preconcentration and separation method for Pd and Pb determination in radiology waste, road dust, soil, and urban aerosol samples. The most favorable feature of this method is its much higher selectivity, sensitivity, rapidity, good extraction efficiency, and employs the green chemistry concept, as it does not require the addition of toxic chemicals. In addition, this proposed method gives very low detection limits and good relative standard. 相似文献7.
Dragun Z Krasnići N Strižak Z Raspor B 《Environmental science and pollution research international》2012,19(6):2088-2095
Purpose
To examine if chronic exposure of feral fish to elevated Pb concentrations in the river water (up to 1???g?L?1), which are still lower than European recommendations for dissolved Pb in surface waters (7.2???g?L?1; EPCEU (Official J L 348:84, 2008)), would result in Pb accumulation in selected fish tissues.Methods
Lead concentrations were determined by use of HR ICP-MS in the gill and hepatic soluble fractions of European chub (Squalius cephalus) caught in the Sutla River (Croatia?CSlovenia).Results
At the site with increased dissolved Pb in the river water, soluble gill Pb levels (17.3???g?L?1) were approximately 20 times higher compared to uncontaminated sites (0.85???g?L?1), whereas the ratio between contaminated (18.1???g?L?1) and uncontaminated sites (1.17???g?L?1) was lower for liver (15.5). Physiological variability of basal Pb concentrations in soluble gill and hepatic fractions associated to fish size, condition, sex, or age was not observed, excluding the possibility that Pb increase in chub tissues at contaminated site could be the consequence of studied biotic parameters. However, in both tissues of Pb-exposed specimens, females accumulated somewhat more Pb than males, making female chubs potentially more susceptible to possible toxic effects.Conclusions
The fact that Pb increase in gill and hepatic soluble fractions of the European chub was not caused by biotic factors and was spatially restricted to one site with increased dissolved Pb concentration in the river water points to the applicability of this parameter as early indicator of Pb exposure in monitoring of natural waters. 相似文献8.
9.
Evaluation of hexachlorocyclohexane contamination from the last lindane production plant operating in India 总被引:3,自引:3,他引:0
Jit S Dadhwal M Kumari H Jindal S Kaur J Lata P Niharika N Lal D Garg N Gupta SK Sharma P Bala K Singh A Vijgen J Weber R Lal R 《Environmental science and pollution research international》2011,18(4):586-597
Purpose
??-Hexachlorocyclohexane (HCH), ??-HCH, and lindane (??-HCH) were listed as persistent organic pollutants by the Stockholm Convention in 2009 and hence must be phased out and their wastes/stockpiles eliminated. At the last operating lindane manufacturing unit, we conducted a preliminary evaluation of HCH contamination levels in soil and water samples collected around the production area and the vicinity of a major dumpsite to inform the design of processes for an appropriate implementation of the Convention.Methods
Soil and water samples on and around the production site and a major waste dumpsite were measured for HCH levels.Results
All soil samples taken at the lindane production facility and dumpsite and in their vicinity were contaminated with an isomer pattern characteristic of HCH production waste. At the dumpsite surface samples contained up to 450?g?kg?1 ?? HCH suggesting that the waste HCH isomers were simply dumped at this location. Ground water in the vicinity and river water was found to be contaminated with 0.2 to 0.4?mg?l?1 of HCH waste isomers. The total quantity of deposited HCH wastes from the lindane production unit was estimated at between 36,000 and 54,000?t.Conclusions
The contamination levels in ground and river water suggest significant run-off from the dumped HCH wastes and contamination of drinking water resources. The extent of dumping urgently needs to be assessed regarding the risks to human and ecosystem health. A plan for securing the waste isomers needs to be developed and implemented together with a plan for their final elimination. As part of the assessment, any polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF) generated during HCH recycling operations need to be monitored. 相似文献10.
Kaisarevic S Hilscherova K Weber R Sundqvist KL Tysklind M Voncina E Bobic S Andric N Pogrmic-Majkic K Vojinovic-Miloradov M Giesy JP Kovacevic R 《Environmental science and pollution research international》2011,18(4):677-686
Purpose
Combinatorial bio/chemical approach was applied to investigate dioxin-like contamination of soil and sediment at the petrochemical and organochlorine plant in Pancevo, Serbia, after the destruction of manufacturing facilities that occurred in the spring of 1999 and subsequent remediation actions.Materials and methods
Soil samples were analyzed for indicator polychlorinated biphenyls (PCBs) by gas chromatography/electron capture detection (GC/ECD). Prioritized soil sample and sediment samples from the waste water channel were analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). Microethoxyresorufin o-deethylase (Micro-EROD) and H4IIE?Cluciferase bioassays were used for monitoring of dioxin-like compounds (DLC) and for better characterization of dioxin-like activity of soil samples.Results
Bioanalytical results indicated high dioxin-like activity in one localized soil sample, while the chemical analysis confirmed the presence of large quantities of DLC: 3.0?×?105 ng/g d.w. of seven-key PCBs, 8.2 ng/g d.w. of PCDD/Fs, and 3.0?×?105 ng/g d.w. of planar and mono-ortho PCBs. In the sediment, contaminant concentrations were in the range 2?C8 ng/g d.w. of PCDD/Fs and 9?C20 ng/g d.w. of PCBs.Conclusions
This study demonstrates the utility of combined application of bioassays and instrumental analysis, especially for developing and transition country which do not have capacity of the expensive instrumental analysis. The results indicate the high contamination of soil in the area of petrochemical plant, and PCDD/Fs contamination of the sediment from the waste water channel originating from the ethylene dichloride production. 相似文献11.
J Chen X Zhou Y Zhang Y Zi Y Qian H Gao S Lin 《Environmental science and pollution research international》2011,19(7):2528-2536
Purpose
The interaction between triclosan (TCS) and human serum albumin (HSA) was investigated in order to obtain the binding mechanism, binding constant, the type of binding force, the binding distance between the donor and acceptor, and the effect of TCS on the conformation change of HSA.Methods
A HSA solution was added to the quartz cell and then titrated by successive addition of TCS. The fluorescence quenching spectra and synchronous spectra were recorded with the excitation and emission slits of the passage of band set at 10 and 20 nm. Three-dimensional fluorescence spectra of HSA were recorded before and after the addition of TCS. The capillary electrophoresis was conducted with the pressure injection mode at 0.5 psi for 5 s, separation under 25 kV, and detection at 214 nm.Results
Fluorescence data indicated the fluorescence quenching of HSA by TCS was static quenching, and the quenching constants (K a ) were 1.14?×?105, 8.75?×?104, 6.67?×?104, and 5.00?×?104 at 293, 298, 303, and 309 K, respectively. The thermodynamic parameters, enthalpy change (??H) and entropy change (??S) for the interaction were calculated to be ?37.9 kJ mol?1 and 32.6 J?mol?1 K?1. The binding distance between TCS and tryptophan residues of HSA was obtained to be 1.81 nm according to F??rster nonradioactive energy transfer theory. The UV-Vis absorption spectroscopy, the synchronous fluorescence spectroscopy, three-dimensional fluorescence spectroscopy, and circular dichroism spectroscopy revealed the alterations of HSA secondary structure in the presence of TCS. Finally, the interaction between TCS and HSA was further confirmed by capillary electrophoresis.Conclusions
TCS was bound to HSA to form the TCS-HSA complex, with the binding distance of 1.81 nm. Hydrophobic interaction and hydrogen bond were dominated in the binding. TCS could change the secondary conformation of HSA. This work provides an insight into noncovalent interaction between emerging pollutants and protein, helping to elucidate the toxic mechanism of such pollutants. 相似文献12.
Ozden O Döğeroğlu T 《Environmental science and pollution research international》2012,19(8):3200-3209
Introduction
This study presents the performance evaluation of a tailor-made passive sampler developed for the monitoring of tropospheric ozone.Methods
The performance of the passive sampler was tested in the field conditions in terms of accuracy, precision, blank values, detection limit, effects of some parameters such as sampling site characteristics and sampling period on the field blanks, self-consistency, experimental and theoretical uptake rates, shelf life and comparison with commercial passive samplers.Results
There was an agreement (R 2?=?0.84) between the responses of passive sampler and the continuous automatic analyser. The accuracy of the sampler, expressed as percent relative error, was obtained lower than 15%. Method precision in terms of coefficient of variance for three simultaneously applied passive samplers was 12%. Sampler detection limit was 2.42???g?m?3 for an exposure period of 1?week, and the sampler can be stored safely for a period of up to 8?weeks before exposure. Satisfactory self-consistency results showed that extended periods gave the same integrated response as a series of short-term samplers run side by side. The uptake rate of ozone was found to be 10.21?mL?min?1 in a very good agreement with the theoretical uptake rate (10.32?mL?min?1). The results of the comparison study conducted against a commercially available diffusion tube (Gradko diffusion tube) showed a good linear relationship (R 2?=?0.93) between two passive samplers.Conclusions
The sampler seems suitable to be used in large-scale measurements of ozone where no data are available or the number of existing automated monitors is not sufficient. 相似文献13.
Devi Prasad Mishra Patitapaban Sahu Durga Charan Panigrahi Vivekanand Jha R. Lokeswara Patnaik 《Environmental science and pollution research international》2014,21(3):2305-2312
This paper presents a comparative study of 222Rn emanation from the ore and backfill tailings in an underground uranium mine located at Jaduguda, India. The effects of surface area, porosity, 226Ra and moisture contents on 222Rn emanation rate were examined. The study revealed that the bulk porosity of backfill tailings is more than two orders of magnitude than that of the ore. The geometric mean radon emanation rates from the ore body and backfill tailings were found to be 10.01?×?10?3 and 1.03 Bq m?2 s?1, respectively. Significant positive linear correlations between 222Rn emanation rate and the 226Ra content of ore and tailings were observed. For normalised 226Ra content, the 222Rn emanation rate from tailings was found to be 283 times higher than the ore due to higher bulk porosity and surface area. The relative radon emanation from the tailings with moisture fraction of 0.14 was found to be 2.4 times higher than the oven-dried tailings. The study suggested that the mill tailings used as a backfill material significantly contributes to radon emanation as compared to the ore body itself and the 226Ra content and bulk porosity are the dominant factors for radon emanation into the mine atmosphere. 相似文献
14.
Tongyan Ren Ping He Weiling Niu Yanjun Wu Lunhong Ai Xinglong Gou 《Environmental science and pollution research international》2013,20(1):155-162
Purpose
Nanomaterials such as iron oxides and ferrites have been intensively investigated for water treatment and environmental remediation applications. The purpose of this work is to synthesize α-Fe2O3 nanofibers for potential applications in removal and recovery of noxious Cr(VI) from wastewater.Methods
α-Fe2O3 nanofibers were synthesized via a simple hydrothermal route followed by calcination. The crystallographic structure and the morphology of the as-prepared α-Fe2O3 nanofibers were characterized by X-ray diffraction, scanning electron microscope, and transmission electron microscope. Batch adsorption experiments were conducted, and Fourier transform infrared spectra were recorded before and after adsorption to investigate the Cr(VI) removal performance and adsorption mechanism. Langmuir and Freundlich modes were employed to analyze the adsorption behavior of Cr(VI) on the α-Fe2O3 nanofibers.Results
Very thin and porous α-Fe2O3 nanofibers have been successfully synthesized for investigation of Cr(VI) removal capability from synthetic wastewater. Batch experiments revealed that the as-prepared α-Fe2O3 nanofibers exhibited excellent Cr(VI) removal performance with a maximum adsorption capacity of 16.17 mg g?1. Furthermore, the adsorption capacity almost kept unchanged after recycling and reusing. The Cr(VI) adsorption process was found to follow the pseudo-second-order kinetics model, and the corresponding thermodynamic parameters ΔG°, ΔH°, and ΔS° at 298 K were calculated to be ?26.60 kJ?mol?1, ?3.32 kJ?mol?1, and 78.12 J?mol?1 K?1, respectively.Conclusions
The as-prepared α-Fe2O3 nanofibers can be utilized as efficient low-cost nano-absorbents for removal and recovery of Cr(VI) from wastewater. 相似文献15.
Purpose
Lack of focus on the treatment of wastewaters bearing potentially hazardous pollutants like 1,1,2 trichloroethane and 1,1,2,2 tetrachloroethane in anaerobic reactors has provided an impetus to undertake this study. The objective of this exercise was to quantify the behavior of upflow anaerobic sludge blanket reactors and predict their performance based on the overall organic substrate removal.Methods
The reactors (wastewater-bearing TCA (R2), and wastewater-bearing TeCA (R3)) were operated at different hydraulic retention times (HRTs), i.e., 36, 30, 24, 18, and 12?h corresponding to food-to-mass ratios varying in the range of 0.2?C0.7?mg chemical oxygen demand (COD) mg?1 volatile suspended solids day?1. The process kinetics of substrate utilization was evaluated on the basis of experimental results, by applying three mathematical models namely first order, Grau second order, and Michaelis-Menten type kinetics.Results
The results showed that the lowering of HRT below 24?h resulted in reduced COD removal efficiencies and higher effluent pollutant concentrations in the reactors. The Grau second-order model was successfully applied to obtain the substrate utilization kinetics with high value of R 2 (>0.95). The Grau second-order substrate removal constant (K 2) was calculated as 1.12 and 7.53?day?1 for reactors R2 and R3, respectively.Conclusion
This study demonstrated the suitability of Grau second-order kinetic model over other models, for predicting the performance of reactors R2 and R3, in treating wastewaters containing chlorinated ethanes under different organic and hydraulic loading conditions. 相似文献16.
Ljubica Župunski Vesna Spasić-Jokić Mirjana Trobok Vojin Gordanić 《Environmental science and pollution research international》2010,17(9):1574-1580
Purpose
The purpose of this paper is to assess fatal cancer risk after external and internal (inhalation and ingestion) exposure from natural radionuclides in soil like 238U, 232Th, 40K, and 226Ra on the territory of Bela Crkva, Serbia. Although receiving doses are low from sources like natural radionuclides in soil, because of stochastic effects of ionizing radiation, risk for developing cancer exists and can be quantified. 相似文献17.
Huang C Chen X Liu T Yang Z Xiao Y Zeng G Sun X 《Environmental science and pollution research international》2012,19(5):1416-1421
Introduction
The suitability of the application of ultrafiltration (UF) to harvest Chlorella sp. from the culture medium was examined. We investigated the effects of two improved UF system, forward air?Cwater flushing and backwash with permeate, on the concentration process.Materials and methods
Backwash with permeate was selected as an optimization of the improved UF system, which was more effective for permeate flux recovery. Moreover, the hollow fiber UF system by adding periodical backwash with permeate was examined for Chlorella sp. harvesting.Results and discussion
It was found that Chlorella sp. could be concentrated with high recovery in a lab-scale experiment. An overall algal biomass recovery of above 90% was achieved when the volume concentration factor was 10. For an original biomass of 1.3?±?0.05?g/L, 1?min backwash followed by 20?min forward concentrating was more effective, which resulted in a recovery of 94% and a high average flux of 30.3?L/m2/h. In addition, the algal recovery was highly correlated to the volume concentration factor and the initial biomass. A high concentration factor or a high initial biomass resulted in a low biomass recovery. 相似文献18.
Testolin RC Tischer V Lima AO Cotelle S Férard JF Radetski CM 《Environmental science and pollution research international》2012,19(6):2186-2194
Background, aim and scope
Agrochemicals could reach aquatic ecosystems and damage ecosystem functionality. Natural formicide could be an alternative to use in comparison with the more toxic formicides available on the market. Thus, the objective of this study was to assess the ecotoxicity of the new natural formicide Macex? with a battery of classical aquatic ecotoxicity tests.Material and methods
Bacteria (Aliivibrio fischeri), algae (Pseudokirchneriella subcapitata), hydra (Hydra attenuata), daphnids (Daphnia magna), and fish (Danio rerio) tests were performed in accordance with international standardized methodologies.Results
In the range of formicide concentrations tested (0.03 to 2.0?g?L?1) EC50 values varied from 0.49 to >2.0?g?L?1, with P. subcapitata being the most sensitive species and H. attenuata and D. rerio the most tolerant species to this product in aqueous solutions.Conclusions
This new formicide preparation can be classed as a product of low toxicity compared to the aquatic ecotoxicity of the most common commercialized formicides. 相似文献19.
Introduction
This study relates to use of zerovalent iron to generate hydroxyl free radicals and undergo subsequent oxidation to destroy 4-nonylphenol (NP) by mild process in aqueous solution and activation of oxygen gas (O2) at room temperature. This technology is based on a novel oxidative mechanism mediated by zerovalent iron rather than commonly used reduction mechanism.Materials and methods
A laboratory scale device consisting of a 250?ml pyrex serum vials fixed to a Vortex agitator was used. Different amounts of zerovalent iron powder (ZVI; 1, 10, and 30?g/l) at pH?4 and room temperature with bubbling of oxygen gas were investigated.Results and conclusion
Experiments showed an observed degradation rate k (obs) directly proportional to the amount of iron. 4-Nonylphenol degradation reactions demonstrated first-order kinetics with a half-life of about 10.5?±?0.5 and 3.5?±?0.2?min when experiments were conducted at [ZVI]?=?1 and 30?g/l respectively. Three analytical techniques were employed to monitor 4-nonylphenol degradation and mineralization: (1) spectrofluorimetry; (2) high-performance liquid chromatography; (3) total organic carbon meter (TOC meter). Results showed a complete disappearance of 4-nonylphenol after 20?min of contact with ZVI. The intermediate by-products of the reaction were not identified but the disappearance of NP was monitored by the three above-mentioned techniques. 相似文献20.
Başak S Cokgör EU Insel G Orhon D 《Environmental science and pollution research international》2012,19(8):3412-3420