The pivot point of delta in Tarbela dam has reached at about 10.6 km from the dam face which may result in blocking of tunnels. Tarbela delta was modeled from 1979 to 2060 using hec-6 model. Initially, the model was calibrated for year 1999 and validated for years 2000, 2001, 2002, and 2006 by involving the data of sediment concentration, reservoir cross sections (73 range lines), elevation-area capacity curves, and inflows and outflows from the reservoir. Then, the model was used to generate future scenarios, i.e., run-1, run-2, and run-3 with pool levels; 428, 442, and 457 m, respectively, till 2060. Results of run-1 and run-2 showed advancement to choke the tunnels by 2010 and 2030, respectively. Finally, in run-3, the advancement was further delayed showing that tunnels 1 and 2 will be choked by year 2050 and pivot point will reach at 6.4 km from the dam face. 相似文献
Numerous contaminants in huge amounts are discharged to the environment from various anthropogenic activities. Waterbodies are one of the major receivers of these contaminants. The contaminated water can pose serious threats to humans and animals, by distrubing the ecosystem. In treating the contaminated water, adsorption processes have attained significant maturity due to lower cost, easy operation and environmental friendliness. The adsorption process uses various adsorbent materials and some of emerging adsorbent materials include carbon- and polymer-based magnetic nanocomposites. These hybrid magnetic nanocomposites have attained extensive applications in water treatment technologies due to their magnetic properties as well as combination of unique characteristics of organic and inorganic elements. Carbon- and polymer-related magnetic nanocomposites are more adapted materials for the removal of various kinds of contaminants from waterbodies. These nanocomposites can be produced via different approaches such as filling, pulse-laser irradiation, ball milling, and electro-spinning. This comprehensive review is compiled by reviewing published work of last the latest recent 3 years. The review article extensively focuses on different approaches for producing various carbon- and polymer-based magnetic nanocomposites, their merits and demerits and applications for sustainable water purification. More specifically, use of carbon- and polymer-based magnetic nanocomposites for removal of heavy metal ions and dyes is discussed in detail, critically analyzed and compared with other technologies. In addition, commercial viability in terms of regeneration of adsorbents is also reviewed. Furthermore, the future challenges and prospects in employing magnetic nanocomposites for contaminant removal from various water sources are presented.
We investigated the impacts of warming and elevated pCO2 on newly settled Amphibalanus improvisus from Kiel Fjord, an estuarine ecosystem characterized by significant natural pCO2 variability. In two experiments, juvenile barnacles were maintained at two temperature and three pCO2 levels (20/24 °C, 700–2,140 μatm) for 8 weeks in a batch culture and at four pCO2 levels (20 °C, 620–2,870 μatm) for 12 weeks in a water flow-through system. Warming as well as elevated pCO2 hardly affected growth or the condition index of barnacles, although some factor combinations led to temporal significances in enhanced or reduced growth with an increase in pCO2. While warming increased the shell strength of A. improvisus individuals, elevated pCO2 had only weak effects. We demonstrate a strong tolerance of juvenile A. improvisus to mean acidification levels of about 1,000 μatm pCO2 as is already naturally experienced by the investigated barnacle population. 相似文献
Recently, although dynamic approaches have been used increasingly to describe metal bioaccumulation in aquatic organisms, the validation of such laboratory-derived modelling is rarely assessed under environmental conditions. The present study aims to evaluate and verify statistical and mathematical models for the bioaccumulation of cadmium (Cd) and to evaluate the suitability of Gammarus pulex as a biomonitor for Cd. To optimise Cd2+ ion bioaccumulation conditions a Box–Behnken design was used and whether G. pulex can be used as an estimated tool to assess aquatic quality was investigated. A Box–Behnken experimental design combined with response surface modelling (RSM) was employed for Cd2+ bioaccumulation in G. pulex. Independent variables including temperature, contact time and Cd2+ ion concentration significance and their interactions were tested using analysis of variance. The selected variables’ optimum values were obtained by solving the quadratic regression model along with by analysing the response surface contour plots. Based on Box–Behnken design, the applied model is significant because model F-value and R2 were obtained as 5121.49, 0.9998, respectively. Bioaccumulation of Cd amount was analysed using electrothermal atomic absorption spectrophotometer. The obtained data suggest that G. pulex can be evaluated as Cd biomonitor. 相似文献
The extracellular extract obtained from 3 weeks incubation of the soil isolate cyanobacterium strain Nostoc piscinale GT-319 in BG-11 broth medium showed cytotoxic activity against Chinese Hamster Ovary (CHO) cells. Based on comet assay, a concentration of 333 µg mL?1 (IC50) produced DNA breakages in CHO cells. The concentration of 481 mg kg?1 (LD50) produced acute toxicity in mice at 48 h. 相似文献
The trophic state of the Anzali wetland was determined by nutrient analysis, indicating an alarming hypertrophic state. The Anzali wetland is environmentally and economically one of the most important ecosystems that is located in north-west Iran. This wetland was registered as a Ramsar site in September 1975, but due to many problems, particularly eutrophication created by excessive amounts of nutrients, it was registered in the Montreux record. This study was conducted for a year on 21 stations in three zones including receiving rivers, surface water and exiting rivers. Geographic information systems were used to better understand the prevailing situation. Analysis was conducted according to international standards and classification of OECD for freshwaters. The indicators used were levels of total nitrogen (TN) and total phosphorous (TP), and the trophic state index (TSI). Data showed an increase of excess nutrients from domestic and agricultural sources, leading to human, cultural eutrophication processes rather than natural eutrophication. 相似文献
Boswellia papyrifera and Boswellia carterii released from smoke contaminate indoor environment and consequently adversely affect humans as evidenced by respiratory disturbances. The aim of this study was to determine the effects of these plants on pathological and biochemical changes in vas deferens of albino rats. Animals were administered 4 g/kg body weight B. papyrifera and B. carterii daily for 120 days along with controls. Significant changes were observed in epithelial cell types and some cells showed signs of degeneration. The ultrastructural studies revealed marked changes in cytoplasmic organelles. Microvilli were missing and lysosomes were found in the cytoplasm. In addition, all treated groups plasma fructose and other biochemical parameters were decreased indicating reduced energy necessary for motility and contractility of spermatozoa. Many spermatozoa were disorganized and agglomerated. Data suggest that smoke from these plants adversely affects vas deferens. 相似文献
Medicinal plants play a crucial role in maintaining human health. Kalanchoe pinnata has been used for treatment of different ailments like infections, rheumatism, and inflammation. Data showed that Kalancho pinnata methanolic extract (100 or 1000 μg/ml) significantly inhibited growth of shoots (hypocotyls) and roots (radicals) of rice compared to control after 3 or 7 days treatment. Further, the Kalancho pinnata methanolic extract (50–1000 μg/ml) exhibited antioxidant properties and scavenged free radicals in dose-dependent manner compared with a standard antioxidant (ascorbic acid). Kalancho pinnata methanolic extract also possesses antifungal property that inhibited approximately 76% and 51% growth of Aspergillus flavous and Aspergillus niger, respectively, using the extract at 200 μg/ml. 相似文献
The fate of key species, such as the barnacle Amphibalanus improvisus, in the course of global change is of particular interest since any change in their abundance and/or performance may entail
community-wide effects. In the fluctuating Western Baltic, species typically experience a broad range of environmental conditions,
which may preselect them to better cope with climate change. In this study, we examined the sensitivity of two crucial ontogenetic
phases (naupliar, cypris) of the barnacle toward a range of temperature (12, 20, and 28°C) and salinity (5, 15, and 30 psu)
combinations. Under all salinity treatments, nauplii developed faster at intermediate and high temperatures. Cyprid metamorphosis
success, in contrast, was interactively impacted by temperature and salinity. Survival of nauplii decreased with increasing
salinity under all temperature treatments. Highest settlement rates occurred at the intermediate temperature and salinity
combination, i.e., 20°C and 15 psu. Settlement success of “naive” cyprids, i.e., when nauplii were raised in the absence of
stress (20°C/15 psu), was less impacted by stressful temperature/salinity combinations than that of cyprids with a stress
history. Here, settlement success was highest at 30 psu particularly at low and high temperatures. Surprisingly, larval survival
was not highest under the conditions typical for the Kiel Fjord at the season of peak settlement (20°C/15 psu). The proportion
of nauplii that ultimately transformed to attached juveniles was, however, highest under these “home” conditions. Overall,
only particularly stressful combinations of temperature and salinity substantially reduced larval performance and development.
Given more time for adaptation, the relatively smooth climate shifts predicted will probably not dramatically affect this
species. 相似文献