خيارات البحث
النتائج 4131 - 4140 من 5,153
Benzo(a)pyrene parallel measurements in PM1 and PM2.5 in the coastal zone of the Gulf of Gdansk (Baltic Sea) in the heating and non-heating seasons النص الكامل
2018
Lewandowska, Anita Urszula | Staniszewska, Marta | Witkowska, Agnieszka | Machuta, Magdalena | Falkowska, Lucyna
Parallel measurements of PM₁ and PM₂.₅ aerosols were conducted in the urbanized coastal zone of the southern Baltic Sea. The main aim of the research was to assess and determine annual, seasonal (heating and non-heating), and daily concentration variability of benzo(a)pyrene in aerosols, these being the most dangerous constituents to human health. The average annual concentration of benzo(a)pyrene (B(a)P) was equal to 2.6 ng·m⁻³ in PM₁ and 4.6 ng·m⁻³ in PM₂.₅, and both values were several times higher than the level of 1 ng·m⁻³ which was set out in the CAFE Directive. High mean daily concentrations of B(a)P persisted for 50 and 65% of the study period in PM1 and PM2.5, respectively. In order to determine the sources of B(a)P in both aerosol fractions, organic (OC) and elemental (EC) carbon concentrations were examined. The highest concentrations of all carbon species were reported during the heating season under local or regional land advection and at low air temperatures. The origin of pollutants was the same and was primarily related to the combustion of fossil fuels in the communal-utility sector. During the non-heating period, the role of transportation, both land and marine, increased and may have been significant in creating higher concentrations of carbon compounds in PM₁ and PM₂.₅. Regardless of the size of the aerosol fractions, B(a)P loads introduced into the Baltic coastal zone were several times higher during the heating period compared to the non-heating season. Graphical abstract ᅟ
اظهر المزيد [+] اقل [-]Converting environmental risks to benefits by using spent coffee grounds (SCG) as a valuable resource النص الكامل
2018
Stylianou, Marinos | Agapiou, Agapios | Omirou, Michalis | Vyrides, Ioannis | Ioannides, Ioannis M. | Maratheftis, Grivas | Fasoula, Dionysia
Coffee is perhaps one of the most vital ingredients in humans’ daily life in modern world. However, this causes the production of million tons of relevant wastes, i.e., plastic cups, aluminum capsules, coffee chaff (silver skin), and spent coffee grounds (SCG), all thrown untreated into landfills. It is estimated that 1 kg of instant coffee generates around 2 kg of wet SCG; a relatively unique organic waste stream, with little to no contamination, separated directly in the source by the coffee shops. The produced waste has been under researchers’ microscope as a useful feedstock for a number of promising applications. SCG is considered a valuable, nutrients rich source of bioactive compounds (e.g., phenolics, flavonoids, carotenoids, lipids, chlorogenic and protocatechuic acid, melanoidins, diterpenes, xanthines, vitamin precursors, etc.) and a useful resource material in other processes (e.g., soil improver and compost, heavy metals absorbent, biochar, biodiesel, pellets, cosmetics, food, and deodorization products). This paper aims to provide a holistic approach for the SCG waste management, highlighting a series of processes and applications in environmental solutions, food industry, and agricultural sector. Thus, the latest developments and approaches of SCG waste management are reviewed and discussed.
اظهر المزيد [+] اقل [-]Upscaling the pollutant emission from mixed recycled aggregates under compaction for civil applications النص الكامل
2018
Galvín, Adela P. | Ayuso, Jesús | Barbudo, Auxi | Cabrera, Manuel | López-Uceda, Antonio | Rosales, Julia
In general terms, plant managers of sites producing construction wastes assess materials according to concise, legally recommended leaching tests that do not consider the compaction stage of the materials when they are applied on-site. Thus, the tests do not account for the real on-site physical conditions of the recycled aggregates used in civil works (e.g., roads or embankments). This leads to errors in estimating the pollutant potential of these materials. For that reason, in the present research, an experimental procedure is designed as a leaching test for construction materials under compaction. The aim of this laboratory test (designed specifically for the granular materials used in civil engineering infrastructures) is to evaluate the release of pollutant elements when the recycled aggregate is tested at its commercial grain-size distribution and when the material is compacted under on-site conditions. Two recycled aggregates with different gypsum contents (0.95 and 2.57%) were used in this study. In addition to the designed leaching laboratory test, the conventional compliance leaching test and the Dutch percolation test were performed. The results of the new leaching method were compared with the conventional leaching test results. After analysis, the chromium and sulphate levels obtained from the newly designed test were lower than those obtained from the conventional leaching test, and these were considered more seriously pollutant elements. This result confirms that when the leaching behaviour is evaluated for construction aggregates without density alteration, crushing the aggregate and using only the finest fraction, as is done in the conventional test (which is an unrealistic situation for aggregates that are applied under on-site conditions), the leaching behaviour is not accurately assessed.
اظهر المزيد [+] اقل [-]Thunderstorm asthma outbreak, a rare phenomenon in southwest Iran: patients’ perspectives النص الكامل
2018
Rabiee, Shohreh | Mousavi, Hassan | Khafaie, Morteza Abdullatif
Previous studies that described thunderstorm asthma, which is a rare event, are not being well explained. This study was conducted, to describe the patient perspective on their asthma attack experience during Ahvaz post-rain phenomenon. We have interviewed patients present in the Naft clinic of Ahvaz, during 28th October and the first week of November 2015. Recruitment was continued as saturation ensued by 33 participants. An inductive content analysis was used to evaluate the interviews. The key finding indicated a climatic condition, direct or indirect contact with rain, history of allergy, and physical conditions are the main categories. The patient emphasized the importance of dust, humidity, first autumn rainfall, and environmental air pollution in occurrences of the event. When exposed to further rains (third rainfall onward), they were less likely to experience dyspnea or shortness of breath. However, being indoor or out at the time of rainfall reported not to be related to the onset of asthma exacerbation. This study yielded that patients’ asthma outbreak is a climate-related health impact and many individual factors triggering this issue. Patients concerns need future investigation and public health emergency planning and response arrangements.
اظهر المزيد [+] اقل [-]Effects of compost and technosol amendments on metal concentrations in a mine soil planted with Brassica juncea L النص الكامل
2018
Forján, Rubén | Rodríguez-Vila, Alfonso | Cerqueira, Beatriz | Covelo, Emma F.
Mining activities often cause important impacts on soil and water quality. The main objective of this study was to evaluate the effect of amendments (compost and technosol made from waste) on metal concentrations in a mine soil planted with Brassica juncea. A greenhouse experiment with cylinder pots was carried out during 11 months. The mine soil was collected from the settling pond of the depleted copper mine of Touro (Galicia, Northwest Spain). A series of characteristics were analysed including soil pseudototal metal concentrations, soil CaCl₂-extractable (phytoavailable) metal concentrations and metal concentrations in soil pore water. The results showed that at depth 0–15 cm SCP (mine soil + compost, grown with B. juncea) had a significantly lower CaCl₂-extractable Cu, Pb, Ni and Zn concentration than STP (mine soil + technosol, grown with B. juncea) over the time (P < 0.05). At depths 15, 30 and 45 cm, STP and SCP had lower Cu pore water concentration than S over the time. The highest translocation factor (TF) values for all metals (Cu, Pb, Ni and Zn) were observed at time 1 (3 months) in the settling pond soils treated with technosol and B. juncea L. The conclusions of this experiment revealed that SCP compared to STP caused a higher reduction on Cu, Pb, Ni and Zn phytoavailable concentrations in the first depths.
اظهر المزيد [+] اقل [-]In situ pilot test for bioremediation of energetic compound-contaminated soil at a former military demolition range site النص الكامل
2018
Jugnia, Louis B. | Manno, Dominic | Drouin, Karine | Hendry, Meghan
Bioremediation was performed in situ at a former military range site to assess the performance of native bacteria in degrading hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4-dinitrotoluene (2,4-DNT). The fate of these pollutants in soil and soil pore water was investigated as influenced by waste glycerol amendment to the soil. Following waste glycerol application, there was an accumulation of organic carbon that promoted microbial activity, converting organic carbon into acetate and propionate, which are intermediate compounds in anaerobic processes. This augmentation of anaerobic activity strongly correlated to a noticeable reduction in RDX concentrations in the amended soil. Changes in concentrations of RDX in pore water were similar to those observed in the soil suggesting that RDX leaching from the soil matrix, and treatment with waste glycerol, contributed to the enhanced removal of RDX from the water and soil. This was not the case with 2,4-DNT, which was neither found in pore water nor affected by the waste glycerol treatment. Results from saturated conditions and Synthetic Precipitation Leaching Procedure testing, to investigate the environmental fate of 2,4-DNT, indicated that 2,4-DNT found on site was relatively inert and was likely to remain in its current state on the site.
اظهر المزيد [+] اقل [-]Performance assessment of laboratory and field-scale multi-step passive treatment of iron-rich acid mine drainage for design improvement النص الكامل
2018
Rakotonimaro, Tsiverihasina V. | Neculita, Carmen Mihaela | Bussière, Bruno | Genty, Thomas | Zagury, Gérald J.
Multi-step passive systems for the treatment of iron-rich acid mine drainage (Fe-rich AMD) perform satisfactorily at the laboratory scale. However, their field-scale application has revealed dissimilarities in performance, particularly with respect to hydraulic parameters. In this study, the assessment of factors potentially responsible for the variations in performance of laboratory and field-scale multi-step systems was undertaken. Three laboratory multi-step treatment scenarios, involving a combination of dispersed alkaline substrate (DAS) units, anoxic dolomitic drains, and passive biochemical reactors (PBRs), were set up in 10.7-L columns. The field-scale treatment consisted of two PBRs separated by a wood ash (WA) reactor. The parameters identified as possibly influencing the performances of the laboratory and field-scale experiments were the following: AMD chemistry (electrical conductivity and Fe and SO₄²⁻ concentrations), flow rate (Q), and saturated hydraulic conductivity (kₛₐₜ). Based on these findings, the design of an efficient passive multi-step treatment system is suggested to consider the following: (1) Fe pretreatment, using materials with high kₛₐₜ and low HRT. If a PBR is to be used, the Fe load should be < 26 g/m³ substrate/day (Fe < 200 mg/L) and SO₄²⁻ < 110 g/m³ substrate/day; (2) PBR/DAS filled with a mixture with at least 20% of neutralizing agent; (3) include Q and kₛₐₜ (> 10⁻³ cm/s) in the long-term prediction. Finally, mesocosm testing is strongly recommended prior to construction of full-scale systems for the treatment of Fe-rich AMD.
اظهر المزيد [+] اقل [-]Sedimentary chronology reinterpreted from Changshou Lake of the Three Gorges Reservoir Area reveals natural and anthropogenic controls on sediment production النص الكامل
2018
Anjum, Raheel | Tang, Qiang | Collins, Adrian L. | Gao, Jinzhang | Long, Yi | Zhang, Xinbao | He, Xiubin | Shi, Zhonglin | Wen, Anbang | Wei, Jie
Sedimentary archives preserved in geomorphic sinks provide records of historical sediment dynamics and its related natural and anthropogenic controls. This study reinterpreted sedimentary processes in Changshou Lake of the Three Gorges Reservoir Area in China by combining a rainfall erosivity index with multiple tracing proxies, and the impacts of natural and anthropogenic drivers on sediment production were also explored. Erosive rainfalls with low frequency and large magnitude in the rainy season contribute to a substantial proportion of annual total rainfall, which thus can be used to infer erosion and sediment yield events. The sedimentary chronology was determined by comparing rainfall erosivity index with depth distribution of ¹³⁷Cs and absolute particle size, which revealed annual sedimentation rates ranging from 1.1 to 2.3 cm a⁻¹. The multi-proxy dating index and variation of sedimentation rate divided the sediment profile into three major periods. The reference period (1956–1982) displays low variability of TOC, TN, trace metal concentrations, and mean sedimentation rate. In the stressed period (1982–1998), industrial and sewerage discharge led to input and deposition of TOC, TN, and trace metals (e.g., Cd, Co, Cu, Cr, and Ni). The highest annual sediment accumulation rate of 2.3 cm a⁻¹ may be ascribed to the 1982 big flood event. In the present period (1998–2013), increased TOC, TN and decreased trace metals in the top layers of the sediment core indicated changes in lake ecology. Fish farming promoted algal growth and primary productivity which caused eutrophication until 2004–2005. The reduced mean sedimentation rate of 1.7 cm a⁻¹ between 1998 and 2004, and thereafter, may be attributed to soil and water conservation and reforestation policies implemented in the Longxi catchment. Human activities such as deforestation, cultural and industrial revolution, and lake eutrophication associated with fish farming since 1989, therefore led to appreciable limnological variations. Overall, the dated sedimentary profile from Changshou Lake displays high consistency with archived historical events and reflects the impact of both natural and anthropogenic controls on sediment production.
اظهر المزيد [+] اقل [-]Correction to: Formation of brominated and chlorinated dioxins and its prevention during a pilot test of mechanochemical treatment of PCB and PBDE contaminated soil النص الكامل
2018
Lu, Mengnan | Lv, Tianwu | Li, Ying | Peng, Zheng | Cagnetta, Giovanni | Sheng, Shouxiang | Huang, Jun | Yu, Gang | Weber, Roland
The destruction of persistent organic pollutants(POPs) is a large challenge in particular in developing and emerging economies.
اظهر المزيد [+] اقل [-]The content of the potentially toxic elements, iron and manganese, in the grapevine cv Tamjanika growing near the biggest copper mining/metallurgical complex on the Balkan peninsula: phytoremediation, biomonitoring, and some toxicological aspects النص الكامل
2018
Alagić, Slađana Č | Tošić, Snežana B. | Dimitrijević, Mile D. | Nujkić, Maja M. | Papludis, Aleksandra D. | Fogl, Viktorija Z.
Plants growing in areas polluted by heavy metals represent excellent models for the investigations related to their potentials for hazardous metals accumulation which further may help in the estimation of plant practical biomonitoring and phytoremediation potentials. In this study, the potentials of the grapevine cultivar Tamjanika from a highly polluted region in Eastern Serbia, with intensive copper mining and metallurgical activities, were estimated in regard to the potentially toxic elements such as iron and manganese; the potential danger from these metals through fruit consummation is also considered. Used methods were the following: ICP-OES analysis, calculation of biological coefficients, the Pearson correlation study, one-way ANOVA, and hierarchical cluster analysis. The results revealed that a great majority of the recorded concentrations in different plant organs were in the range of normal concentrations, as well as that the calculated accumulation rates for both metals were very low. The data also pointed to generally minimal to moderate enrichment by these metals which represents totally dissimilar situation in comparison with other heavy metals detected in the very same plant samples. The results of this study suggested that the investigated plants of the grapevine cv Tamjanika assimilated iron and manganese predominately according to their individual needs, and confirmed that the utilization of this plant species can be very effective in different biomonitoring procedures and also in the phytoremediation procedure known as phytostabilization. At the same time, it was obvious that even in aggressive circumstances its fruit was protected from some serious contamination and kept pretty safe for consummation.
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