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Accumulation of Major and Trace Elements in Spider Webs Texte intégral
2015
Rybak, Justyna
The spider webs of Malthonica ferruginea (Panzer, 1804) from the Agelenidae family were used for the evaluation of heavy metal contamination, and major and trace elements presence in the air of Wrocław, Poland. The concentrations of 16 elements were determined (Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, W, Pt, and Pb). Samples of webs were collected from six different locations with low, moderate, and high pollution level (urban of low and high traffic, residential, and postindustrial sites) after 60 days of exposure. Samples collected from high traffic sites and postindustrial site were found to have high contents of elements than residential sites and one of low traffic urban site. The principle component analysis (PCA) and correlation analysis provide important information about the potential sources of the elements in spider webs. Two contamination sources were identified: road traffic emissions and industrial. This was a first-time ever attempt to use webs for biomonitoring of small-scale distribution of airborne major and trace elements in the city of Wrocław.
Afficher plus [+] Moins [-]Analysis of a Study of Lead Wheel Weight Deposition and Abrasion in New Jersey Texte intégral
2015
Root, Robert A.
This paper analyzes the implications for children’s health of shortcomings in the methods and results of a study of lead in the environment, “Quantity of Lead Released to the Environment in New Jersey in the Form of Motor Vehicle Wheel Weights,” by the New Jersey Department of Environmental Protection (Aucott and Caldarelli, Water, Air, & Soil Pollution, 223, 1743–1752, 2012). The study significantly understates the amount of lead deposited in New Jersey streets as 12 metric tons per year and incorrectly concludes that only 40 kg per year of the lead from wheel weights is abraded into small particles. The 2012 New Jersey Department of Environmental Protection (NJDEP) study misleads regulators and the public into believing that little toxic particulate lead from abraded wheel weights occurs on the streets of New Jersey and by implication that little occurs elsewhere in the United States, thus minimizing the potential health risk that lead wheel weights may have to our nation’s children and indeed all of us.
Afficher plus [+] Moins [-]Deployment of Microbial Biosensors to Assess the Performance of Ameliorants in Metal-Contaminated Soils Texte intégral
2015
Maletić, Snežana P. | Watson, Malcolm A. | Dehlawi, Saad | Diplock, Elizabeth E. | Mardlin, David | Paton, Graeme I.
The remediation of metal-impacted soils requires either the enhanced mobility (and capture) of the target analytes or their effective complexation/immobilisation. In this study, a range of ameliorants (activated carbon, bonemeal, bentonite and CaSx (calcium polysulphide)) were compared to assess their effectiveness in immobilising metals in soils. In addition to chemical analysis (pH and trace element analysis), microbial biosensors were used to assess changes in the water-soluble biotoxicity of metals as a consequence of ameliorant dosing. Management of soil ameliorants requires an enhancement of K d (solid/solution partition coefficient) if soil leachate is to meet predefined environmental quality standards. Of the ameliorants tested, CaSx was the most effective per unit added for both laboratory-amended and historically contaminated soils, regardless of the metal tested. At the ameliorant concentrations used to effectively immobilise the metals, the biosensor performance was not impaired. Microbial biosensors offered a rapid and relevant screening tool to validate the reduced toxicity associated with the ameliorant dosing and could be calibrated to complement chemical analysis. While laboratory-amended soils were a logical way to evaluate the performance of the ameliorants, they were generally associated with K d values an order of magnitude lower than those of historically contaminated soils.
Afficher plus [+] Moins [-]Concentrations of 18 Elements in Muscle, Liver, Gills, and Gonads of Sichel (Pelecus cultratus), Ruffe (Gymnocephalus cernua), and European Perch (Perca fluviatilis) in the Danube River near Belgrade (Serbia) Texte intégral
2015
Subotić, S. | Višnjić-Jeftić, Ž | Spasić, S. | Hegediš, A. | Krpo-Ćetković, J. | Lenhardt, M.
The analysis of 18 elements in muscle, liver, gills, and gonads of sichel (Pelecus cultratus), ruffe (Gymnocephalus cernua), and European perch (Perca fluviatilis), caught at a polluted segment of the Danube River near Belgrade, was carried out with the aim to expand the knowledge about the ecotoxicology of these species for monitoring purposes and the possible impact on human health. Generally, the elemental concentration significantly differed between species and tissues (p < 0.0001), and a statistical interaction between these two factors was observed (p < 0.0001). In muscle and liver, concentrations of Hg and Se were statistically higher in ruffe than in sichel and European perch. In gills, statistically highest concentrations of Mn, Sr, and Zn were found in sichel, and of Fe in European perch. In gonads, statistically highest concentrations of As were detected in sichel, of Zn in ruffe, and of Mn and Mo in European perch. The highest number of coefficients of partial correlations between fish weight and element levels was found in sichel (11 in total). Of all analyzed elements, Al and B had the highest number of partial correlations in tissues. The levels of Hg exceeded the maximum acceptable concentration (0.5 mg kg⁻¹) in all muscle samples, which can pose a risk for human consumption. Different diet preferences of the investigated fish species resulted in a different accumulation of elements in tissues, and ruffe (as a species that consume mainly benthic macroinvertebrates) accumulated the highest level of Hg, which makes it suitable for monitoring of this element in water bodies.
Afficher plus [+] Moins [-]Characterisation of Prolonged Deposits of Organic Matter in Infiltration System Inlets and Their Binding with Heavy Metals: a PARAFAC Approach Texte intégral
2015
Aryal, Rupak | Furumai, Hiroaki | Nakajima, Fumiyuki | Beecham, Simon | Kandasamy, Jaya
This study investigated and characterised organic matter present in sediment particles deposited in infiltration facilities using an excitation-emission matrix method combined with parallel factor analysis (EEM-PARAFAC). The organic fluorophore identified was correlated with sediment bound metals. The PARAFAC analysis identified three major components. The fluorophore in each of the three components appeared in different locations with different spectral shapes. The maximum fluorescence intensity (F ₘₐₓ) observed for each fluorescent component was correlated with seven heavy metals (Cr, Mn, Co, Ni, Cu, Zn and Pb). F ₘₐₓ of component 1 displayed a negative relationship with all the metals (correlation coefficient = −0.28 to −0.72), and F ₘₐₓ of component 3 showed a positive relationship (0.20 to 0.62), and among them, Cu, Ni and Zn had higher correlation. Our results demonstrate that a PARAFAC approach can help to further elucidate organic matter species, thereby allowing a better understanding of the mobility of elemental species in the deposited sediment.
Afficher plus [+] Moins [-]Speciation in Application Environments for Dissolved Carbon Dioxide Sensors Texte intégral
2015
Bhatia, Sonja | Risk, David
Measurement of the concentration of dissolved carbon dioxide in ground and surface aqueous environments is needed for a wide variety of scientific and industrial applications. These environments can be fresh, saline, or transitional in nature and can be hydrochemically complex. A next generation of sensors, like fiber-optic sensors, offer real-time, direct, distributed sensing of dissolved carbon dioxide and are an improvement over current technology for many applications; however, these sensors may be susceptible to signal disturbance when deployed in hydrochemically complex, natural environments. This complexity can best be characterized using hydrochemical modeling techniques. The modeling software, phreeqc 2.18, was used to conduct a comprehensive review to gain perspective on published data of natural water samples. Freshwater, saltwater, and transitional environments were characterized in terms of the distribution of carbonate and non-carbonate species present. Saline, transitional, and deep freshwater environments had the broadest range of carbonate distribution and species that may cross-interfere with sensor response. These data should be used to build complex laboratory test solutions that mimic the natural environment for use in sensor development. In some cases, specially engineered membranes may be required to mitigate the potentially cross-interfering effect of these ions.
Afficher plus [+] Moins [-]An Assessment of Morphological, Physiological and Biochemical Biomarkers of Industrial Air Pollution in the Leaves of Brachylaena discolor Texte intégral
2015
Areington, Candyce Ann | Varghese, Boby | Ramdhani, Syd | Sershen,
Bioindicators are useful in monitoring air pollution. This study assessed the efficacy of various tree leaf morphological, physiological and biochemical biomarkers in reflecting different intensities of air pollution. Leaves from Brachylaena discolor trees growing 0, 2.5, 6 and 11 km from an industrial hub (pollution source) in eThekwini, South Africa, were analysed for leaf area, chlorophyll (Chl) content, superoxide and hydrogen peroxide (H₂O₂) production, electrolyte leakage, total antioxidant activity and concentration of selected minerals. B. discolor saplings grown under greenhouse conditions served as an ex situ control. Surface SO₂ and NOₓ levels which were measured at the in situ and control sites declined significantly with increasing distance from the source but were below detectable limits at the control site. At the site closest to the source, leaf area was significantly lower and Chl, electrolyte leakage, and copper (Cu) and phosphorous (P) levels were significantly higher than the control. Leaf area was significantly positively, and Chl content significantly negatively, correlated with distance from the source, while H₂O₂ production, electrolyte leakage and Cu and P concentrations were all significantly negatively correlated with distance from the source. The aforementioned parameters represent potential biomarkers of air pollution in B. discolor and in some cases (e.g., H₂O₂ and electrolyte leakage; leaf area and leaf Chl content) should be measured in conjunction with each other to accommodate for interactive effects. Using B. discolor leaves as bioindicators of air pollution may represent a more viable option for monitoring air pollution than monitoring stations.
Afficher plus [+] Moins [-]Sunlight-Assisted Photo-Fenton Degradation of Pesticide in Wastewater: Ecotoxicological Impact on Nostoc sp. Algae Texte intégral
2015
Dutta, Amrita | Cakrabartī, Īśitā | Sarkar, Debasish | Chakrabarti, Sampa
Solar Photo-Fenton reaction, using FeSO₄ and H₂O₂, is an effective and energy-efficient advanced oxidation process (AOP) for degradation of pesticides. However, a major environmental concern is whether the net toxicity after the photo-Fenton process is within the tolerance limit of the aquatic plants and animals, since the unreacted pesticide and Fenton’s reagent may impart additional toxicity to the treated water. Here, we report the oxidative removal of dichlorvos pesticide in wastewater by solar photo-Fenton reaction along with the residual toxicity analysis of the treated water on an aquatic alga. It was found that at pH 3, dichlorvos, with an initial concentration of 6.9 × 10⁻⁵ mol L⁻¹, was observed to be fully degraded within a batch time of 120 min, though the corresponding reduction of chemical oxygen demand (COD) was about 53 % signifying incomplete mineralisation. In order to predict the transient concentration profiles of dichlorvos under different initial concentrations, a four-parameter mathematical model was formulated. Additionally, the resultant toxicity was also examined using a model blue-green alga Nostoc sp. Compared to the raw wastewater, the net biomass of chlorophyll-a was found to increase significantly. Respective estimate of the protein concentration also indicated the same trend. Therefore, sunlight-assisted photo-Fenton process may be regarded as an effective and safe technique for the treatment of pesticide-contaminated agricultural wastewater.
Afficher plus [+] Moins [-]Arsenic Accumulation in Panax notoginseng Monoculture and Intercropping with Pteris vittata Texte intégral
2015
Lin, L. Y. | Yan, X. L. | Liao, X. Y. | Zhang, Y. X. | Ma, X.
Panax notoginseng is a well-known phytomedicine used all over the world. In recent years, a certain As contamination of the herb appeared in its planting area due to elevated soil As concentration. We investigated the feasibility of intercropping with Pteris vittata, an As hyperaccumulator, on the reduction of As accumulation in Panax notoginseng and As transfer and transformation in soil-plant system. Results showed that, intercropping could decrease the As concentrations of Panax notoginseng by 9.1–54.3 and 30.9–54.3% and increase the biomasses by 40.7–211.6 and 2.1–153.3 %, respectively, in the H-As (soil As 400.4 mg/kg) and M-As (soil As 85.3 mg/kg) treatments. Compared to the monoculture, the ratio of the nonspecifically adsorbed As in soil was decreased by 17.8 and 34.3 %, and the As transfer factor of Panax notoginseng was increased by 22.2 and 66.3 %, respectively, in H-As and M-As treatments. For As speciation, As(III) and As(V) could be detected at the same time only in root and xylem sap of Panax notoginseng in the H-As treatment, and intercropping could increase the ratios of As(III) by 97.8 and 72.4 %, respectively. In summary, intercropping with Pteris vittata is an applicable approach to reduce the As accumulation in Panax notoginseng.
Afficher plus [+] Moins [-]The Treatment Performance and the Bacteria Preservation of Anammox: A Review Texte intégral
2015
He, Shilong | Niu, Qigui | Ma, Haiyuan | Zhang, Yanlong | Li, Yu-You
Because of the low energy costs in the absence of the need for aeration, the non-requirement of a carbon source and alkali, and the reduced production of excess sludge, anaerobic ammonia oxidation (Anammox) has been extensively studied as an alternative to the conventional nitrification–denitrification pathway for biological nitrogen removal from wastewater. However, many challenges remain which need to be overcome to prepare the process for engineering application. These include the long doubling time of Anammox bacteria/autotrophic ammonia-oxidizing bacteria (AAOB), the low tolerance capacity to substrate concentration, and high sensitivity to various environmental factors. This review article focuses on the main drawbacks of the Anammox process and evaluates the progress made to date with regard to the enrichment of AAOB and the treatment performance of the Anammox process itself. The factors affecting the nitrogen removal performance of the Anammox process, such as substrate concentration, organic matters, and variation of temperature, are also reviewed and discussed. Finally, the need for the development of long-term storage methods for AAOB is addressed.
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