9 results on '"Environmental parameters"'
Search Results
2. Cascaded reservoirs promote phosphorus bioavailability of surface sediments in the Upper Mekong River.
- Author
-
Yang, Zhengjian, Min, QiFeng, Guo, Xiaojuan, Wang, Congfeng, Yan, Bi''e, Li, Xiaoling, Liu, Defu, Ma, Jun, and Lorke, Andreas
- Published
- 2024
- Full Text
- View/download PDF
3. Environmental impact assessment on the stone decay in the archaeological site of Hierapolis (Denizli, Turkey).
- Author
-
Vettori, Silvia, Cabassi, Jacopo, Cantisani, Emma, and Riminesi, Cristiano
- Abstract
Abstract The archaeological site of Hierapolis (Denizli province, Turkey) is unique in terms of the conservation of marbles and travertines. Environmental factors (i.e. interaction with thermal waters, high thermal stress, CO 2 degassing) and geological aspects (presence of seismic faults, frequent earthquakes, formation of travertine) play a fundamental role in the durability and conservation state of the stone materials. This paper presents a multi-analytical approach aimed to identify the phenomena and causes of stone decay related to environmental conditions. The analyses of alteration and decay phenomena are discussed together with the monitoring of the main environmental parameters and with analyses of waters and gases present in the archaeological site. Finally, the need of a continuous monitoring of the environmental parameters affecting the archaeological site is stressed. Graphical abstract Unlabelled Image Highlights • A multi-analytical approach allows a huge data acquisition regarding the state of conservation of an archaeological site. • The phenomena and causes of stone decay related to environmental conditions were evaluated. • Monitoring of environmental parameters (T and RH) and analyses of water and gas chemical composition were performed. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
4. Normalizing land surface temperature for environmental parameters in mountainous and urban areas of a cold semi-arid climate.
- Author
-
Weng, Qihao, Firozjaei, Mohammad Karimi, Kiavarz, Majid, Alavipanah, Seyed Kazem, and Hamzeh, Saeid
- Abstract
Abstract Normalization of land surface temperature (LST) relative to environmental factors is of great importance in many scientific studies and applications. The purpose of this study was to develop physical models based on energy balance equations for normalization of satellite derived LST relative to environmental parameters. For this purpose, a set of remote sensing imagery, meteorological and climatic data recorded in synoptic stations, and soil temperatures measured by data loggers were used. For modeling and normalization of LST, a dual-source energy balance model (dual-EB), taking into account two fractions of vegetation and soil, and a triple -source energy balance model (triple-EB), taking into account three fractions of vegetation, soil and built-up land, were proposed with either regional or local optimization strategies. To evaluate and compare the accuracy of different modeling results, correlation coefficients and root mean square difference (RMSE) were computed between modeled LST and LST obtained from satellite imagery, as well as between modeled LST and soil temperature measured by data loggers. Further, the variance of normalized LST values was calculated and analyzed. The results suggested that the use of local optimization strategy increased the accuracy of the normalization of LST, compared to the regional optimization strategy. In addition, no matter the regional or local optimization strategy was employed, the triple-EB model out-performed consistently the dual-EB model for LST normalization. The results show the efficiency of the local triple-EB model to normalize LST relative to environmental parameters. The correlation coefficients were close to zero between all of the environmental parameters and the normalized LST. In other words, normalized LST was completely independent of the environmental parameters considered by this research. Graphical abstract Unlabelled Image Highlights • Normalization of LST relative to environmental parameters is significant in climate. • Triple-EB model f\or modeling LST increased the accuracy over the Dual-EB model. • Local optimization was more efficient than regional optimization to normalize LST. • The developed protocol was applicable both to mountainous and urban areas. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
5. Photocatalytic degradation of carbamazepine and three derivatives using TiO2 and ZnO: Effect of pH, ionic strength, and natural organic matter.
- Author
-
Haroune, Lounes, Salaun, Maria, Ménard, Alain, Legault, Claude Y., and Bellenger, Jean-Philippe
- Subjects
- *
PHOTOCATALYTIC oxidation , *PHOTOCATALYSIS , *CARBAMAZEPINE , *TITANIUM dioxide , *ZINC oxide , *CHEMICAL derivatives , *PHOTODEGRADATION - Abstract
Abstract: Removal of pharmaceuticals (PhCs) by photocatalysis is a promising avenue in water treatment. The efficiency of these treatments on PhC derivatives compared to their parent molecules remains poorly documented. The present study investigates the efficiency of photodegradation catalyzed by TiO2 and ZnO nanoparticles on the removal of carbamazepine (CBZ) and three of its derivatives; carbamazepine epoxide (CBZ-E), acridine (AI), and acridone (AO). The effects of environmental parameters such as pH, ionic strength, and natural organic matter content on photodegradation efficiency (transformation after 6h and kinetics) were tested. We report that the efficiency of the catalysts (TiO2 and ZnO) can be very different when comparing CBZ and its derivatives (CBZ-E, AI and AO). TiO2 was more efficient than ZnO at degrading CBZ and CBZ-E. For AI and AO, no significant differences were observed between the two catalysts. We also report that environmental parameters have contrasting effects on the efficiency of the photodegradation of CBZ compared to its derivatives. Changing pH and organic matter content had the most contrasted effects; the photodegradation of CBZ and CBZ-E was significantly affected by pH (especially in presence of TiO2 NPs) and by the presence of natural organic matter. In contrast, the photodegradation of AI and AO was not affected by pH and organic matter. Only the photodegradation of CBZ was clearly affected by IS and solely at very high IS (1M). Overall, our results highlight that TiO2 and ZnO catalysts present contrasted efficiency on the removal of CBZ when compared to its derivatives (CBZ-E, AI and AO). Our results also show that the effect of environmental parameters on the efficiency of the photodegradation of CBZ derivatives cannot be predicted based on the behavior of the parent molecule (CBZ). [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
6. Impact of mixed land-use practices on the microbial water quality in a subtropical coastal watershed
- Author
-
Liang, Zhanbei, He, Zhenli, Zhou, Xuxia, Powell, Charles A., Yang, Yuangen, He, Li Ming, and Stoffella, Peter J.
- Subjects
- *
LAND use , *ENVIRONMENTAL impact analysis , *WATER quality , *WATERSHEDS , *RUNOFF & the environment , *AQUATIC microbiology , *BODIES of water , *DISSOLVED organic matter - Abstract
Abstract: Surface runoff water is an important non-point source of fecal pollution to downstream water; however, there is a lack of systematic studies on the microbial quality of surface runoff water from watersheds with mixed land uses. In this study water samples from 12 surface runoff holding water bodies (SRW), which collected runoff from various patterns of land use within the St. Lucie watershed along the southeastern coastline of Florida, were collected monthly for 22months. The concentration of fecal indicator bacteria (FIB) and frequency of detection of Salmonella and host specific markers (HF183, CF128, CF193, and HS-esp) were determined, and their associations with land use, rainfall, and water physico-chemical parameters were investigated. Higher FIB concentrations were observed from urban land and cattle ranch sites. Within the same primary land use pattern, different sub-patterns did not have the same level of FIB: golf communities contributed less to fecal pollution than residential areas, and plant nursery sites contained relative higher FIB concentrations than other agricultural sites. Salmonella, CF128, and CF193 markers were more frequently detected from the cattle ranch sites. In contrast the frequency of detecting human specific markers (HF183 and HS-esp) was much higher in residential sites. Rainfall positively affected the concentration of FIB and occurrence of Salmonella, possibly by providing more inputs or mobilizing the sources from sediments. Water temperature, dissolved organic carbon (DOC), and nutrient levels were positively correlated with FIB concentrations and occurrence in SRW, possibly by promoting their growth and survival. This study indicated the need for site specific mitigation strategies to improve SRW and downstream water quality. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
7. Comparison of mercury speciation and distribution in the water column and sediments between the algal type zone and the macrophytic type zone in a hypereutrophic lake (Dianchi Lake) in Southwestern China
- Author
-
Wang, Shaofeng, Zhang, Mingmei, Li, Biao, Xing, Denghua, Wang, Xin, Wei, Chaoyang, and Jia, Yonfeng
- Subjects
- *
LAKE sediments , *HEAVY metal content of water , *MERCURY & the environment , *ALGAL blooms , *EUTROPHICATION , *WATER temperature - Abstract
Abstract: During a heavy algal bloom in 2009, we collected lake water, surface sediment, sediment cores and porewater samples from Dianchi Lake to investigate the effect of eutrophication and different aquatic habitats (algal and macrophytic) on mercury (Hg) distribution and speciation in hypereutrophic lake. The total Hg (THg) concentration in the sediment and lake water was substantially elevated compared to uncontaminated lakes and reservoirs. The spatial distribution of THg pointed to waste water discharged from Kunming City as the dominant source of Hg in Dianchi Lake. Despite the high concentration of THg, the concentration of methyl mercury (MeHg) was relatively low compared to other deep water lakes and reservoirs, and the ratio of MeHg/THg was generally lower than 1% in lake water and sediments, implying the low potential of Hg methylation. No significant relationship was found between the total organic carbon (TOC) and MeHg in either surface sediment or sediment cores. This result is different from previous conclusions that an increase of organic material load in sediment can enhance the potential of Hg methylation in sediments. A significant relationship between the total S and MeHg in the two cores indicated that sulfur played an important role in Hg methylation. However, because of similar concentrations of MeHg and distinct differences in the S concentration in the two cores, the total S should not be a limiting factor for Hg methylation in sediment. The most important limiting factors controlling Hg methylation were high pH and Eh induced by heavy algal blooms and shallow water depth in Dianchi Lake because Hg methylation will be inhibited and the demethylation of MeHg may be accelerated under alkaline and oxic conditions. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
8. Biomarker versus environmental factors: Seasonal variations and modelling multixenobiotic defence (MXD) transport activity in transplanted zebra mussels
- Author
-
Pain, Sandrine, Devin, Simon, and Parant, Marc
- Subjects
- *
MARINE pollution monitoring , *ZEBRA mussel , *BIOMARKERS , *AQUATIC ecology , *LINEAR statistical models , *POLLUTION - Abstract
The occurrence of biomarker temporal variations linked to environmental factors makes it difficult to distinguish the specific effect of pollution. The present work aims to investigate the seasonal variations of the transport activity of the multixenobiotic defence (MXD), which is used as a biological tool for the monitoring of pollution in aquatic ecosystems. The MXD transport activity was monitored monthly from August 2001 to October 2002 in zebra mussels (Dreissena polymorpha) transplanted to three sites in the Moselle River. The ‘efflux method’ was used to evaluate functional activity of MXD by assessing rhodamine B efflux with or without an inhibitor (verapamil). Environmental parameters were provided by a French regulatory agency (Water Agency) that monitors river water quality. The results of a principal components analysis describe the seasonal cycle of water characteristics and demonstrate that MXD activity is subjected to significant temporal variations. These data were described with a generalised linear model that enables it to link MXD variability to the seasonal variations of environmental parameters such as temperature or levels of organic contamination. This work proposes a modelling approach and highlights that the occurrence of seasonal variations in MXD response has to be taken into account in the interpretation of in situ monitoring studies. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
9. Photocatalytic degradation of carbamazepine and three derivatives using TiO₂ and ZnO: effect of pH, ionic strength, and natural organic matter.
- Author
-
Haroune L, Salaun M, Ménard A, Legault CY, and Bellenger JP
- Subjects
- Osmolar Concentration, Photolysis, Ultraviolet Rays, Water Purification methods, Carbamazepine chemistry, Titanium chemistry, Water Pollutants, Chemical chemistry, Zinc Oxide chemistry
- Abstract
Removal of pharmaceuticals (PhCs) by photocatalysis is a promising avenue in water treatment. The efficiency of these treatments on PhC derivatives compared to their parent molecules remains poorly documented. The present study investigates the efficiency of photodegradation catalyzed by TiO₂ and ZnO nanoparticles on the removal of carbamazepine (CBZ) and three of its derivatives; carbamazepine epoxide (CBZ-E), acridine (AI), and acridone (AO). The effects of environmental parameters such as pH, ionic strength, and natural organic matter content on photodegradation efficiency (transformation after 6h and kinetics) were tested. We report that the efficiency of the catalysts (TiO2 and ZnO) can be very different when comparing CBZ and its derivatives (CBZ-E, AI and AO). TiO₂ was more efficient than ZnO at degrading CBZ and CBZ-E. For AI and AO, no significant differences were observed between the two catalysts. We also report that environmental parameters have contrasting effects on the efficiency of the photodegradation of CBZ compared to its derivatives. Changing pH and organic matter content had the most contrasted effects; the photodegradation of CBZ and CBZ-E was significantly affected by pH (especially in presence of TiO₂ NPs) and by the presence of natural organic matter. In contrast, the photodegradation of AI and AO was not affected by pH and organic matter. Only the photodegradation of CBZ was clearly affected by IS and solely at very high IS (1M). Overall, our results highlight that TiO₂ and ZnO catalysts present contrasted efficiency on the removal of CBZ when compared to its derivatives (CBZ-E, AI and AO). Our results also show that the effect of environmental parameters on the efficiency of the photodegradation of CBZ derivatives cannot be predicted based on the behavior of the parent molecule (CBZ)., (Copyright © 2013 Elsevier B.V. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.