A 3-D finite element model (Feflow) has been used for regional groundwater flow modelling of Upper Chaj Doab in Indus Basin, Pakistan. The thematic layers of soils, landuse, hydrology, infrastructure and climate were developed using Geographic Information System (GIS). The numerical groundwater flow model is developed to configure the groundwater equipotential surface, hydraulic head gradient and estimation of the groundwater budget of the aquifer. Integration of GIS with groundwater modelling and satellite remote sensing capabilities has provided an efficient way of analysing and monitoring groundwater status and its associated land conditions. The Arcview GIS software is used as additive tool to develop supportive data for numerical groundwater modelling, integration and presentation of image processing and modelling results. The groundwater behaviour of the regional model shows a gradual decline in watertable from year 1999 onward. The persistent dry condition and high withdrawal rates play an influential role in lowering down the groundwater levels. Different scenarios were developed to study the impact of extreme climatic conditions (drought/flood) and variable groundwater abstraction on the regional groundwater system. The results of the study provide useful information regarding the behaviour of aquifer in order to organize management schemes on local and regional basis to monitor future groundwater development in the area. 相似文献
In agricultural production, specific elements in soil and plants are very important for the soil quality and plant productivity. Trace elements and rare earth elements enter in agri-environment by the application of fertilizers and, through anthropogenic activities, pose important health impacts even at low concentration due to non-biodegradable nature with long half-life. The micro nutrients are essential for human body in a quantity most of less than 100 mg/day. The nutritional element uptake by plants is regulated by availability of the required elements and element accumulation ability of the plants. Therefore, this study was aimed to investigate the accumulation of trace and rare earth elements after long-term application of different fertilizers in soil and soybean uptake. The inorganic fertilizers (NKP) and pig manure were applied to maize-maize-soybean rotation in Alfisols (brown) soil since 1979. Atomic emission spectrometry along with inductively coupled plasma technique was applied to determine trace and rare earth elements. The accumulation pattern of trace elements (TEs) observed in soil was Ni > Co > Se > Mo and rare earth elements (REEs) was found as La > Nd > Tb > Y > Pr > Gd > Er > Yb > Lu. In soybean stem, the TE and REE concentrations were Se > Ni > Co > Mo and Pr > Gd > Er > Yb > Tb > Nd > Lu > La > Y, respectively. Elemental concentrations in the seed samples were Ni > Se > Mo > Co and Pr > Gd > Er > Yb > Tb > Nd > Lu > Y > La. The seed of soybean accumulated Co, Mo, Ni, Gd, Pr, Er, Lu, and Tb more than the stem. Higher concentrations of Se, Nd, Y, and Yb were found in soil. These elements were higher in soybean stem followed by the seed. However, these elements are within safe toxic level and light pollution level. 相似文献
This paper provides for the first time an experimental study where the impact of sea‐level fluctuations and inland boundary head‐level variations on freshwater–saltwater interface toe motion and transition zone dynamics was quantitatively analysed under transient conditions. The experiments were conducted in a laboratory flow tank where various (inland and coastal) head changes were imposed to the system and the response of the key seawater intrusion parameters was analysed with high spatial and temporal resolution. Two homogeneous aquifer systems of different grain size were tested. The numerical code SEAWAT was used for the validation. The results show that in cases of sea‐level variations, the intruding wedge required up to twice longer time to reach a new steady‐state condition than the receding wedge, which thereby extend the theory of timescale asymmetry between saltwater intrusion and retreat processes in scenarios involving sea‐level fluctuations. The intruding and receding rates of the saltwater wedge were respectively similar in the scenario involving sea‐level and the freshwater‐level changes, despite change in transmissivity. The results show that, during the intrusion phase, the transition zone remains relatively insensitive, regardless of where the boundary head change occurs (i.e., freshwater drop or sea‐level rise) or its magnitude. By contrast, a substantial widening of the transition zone was observed during the receding phase, with almost similar amplitude in the scenario involving a rise of the freshwater level compared with that caused by a drop of the saltwater level, provided that an equivalent absolute head change magnitude was used. This transition zone widening (occurring during saltwater retreat) was greater and extended over longer period in the low hydraulic conductivity aquifer, for both freshwater‐level rise and sea‐level drop scenarios. The concentration maps revealed that the widening mechanism was also enhanced by the presence of some freshwater sliding and into the wedge during saltwater retreat, which was thereafter sucked upward towards the interface because of density difference effects. 相似文献
Textile wastewater contains huge quantities of nitrogen (N)‐containing azo‐dyes. Irrigation of crops with such wastewater adds toxic dyes into our healthy soils. One of the ways to prevent their entry to soils could be these waters after the dyes' biodegradation. Therefore, the present study was conducted to evaluate the impact of textile dyes on wheat growth, dye degradation efficiency of bacteria‐fungi consortium, and alleviation of dye toxicity in wheat by treatment with microbial consortium. Among dyes, Red‐S3B (3.19% N) was found to be the most toxic to germination and growth of seven‐day‐old wheat seedlings. Shewanella sp. NIAB‐BM15 and Aspergillus terreus NIAB‐FM10 were found to be efficient degraders of Red‐S3B. Their consortium completely decolorized 500 mg L?1 Red‐S3B within 4 h. Irrigation with Red‐S3B‐contaminated water after treatment with developed consortium increased root length, shoot length, root biomass, and shoot biomass of 30‐day‐old wheat seedlings by 47, 18, 6, and 25%, respectively, than untreated water. Moreover, irrigation after microbial treatment of dye‐contaminated water resulted in 20 and 51% increase in shoot N content and N uptake, respectively, than untreated water. Thus, co‐inoculation of bacteria and fungi could be a useful bioremediation strategy for the treatment of azo‐dye‐polluted water. 相似文献
Natural Hazards - Successful management of the water resources directly depends on our understanding of the heterogeneity of changing climate and consequent response of annual and seasonal... 相似文献
This study was conducted to evaluate the effect of replacing soybean meal (SBM) by low protein floc meal (LPFM; 24% CP) in tilapia diets on growth performance, feed utilization and fish chemical composition. Three isonitrogenous and isocaloric diets were formulated; control diet (C; without LPFM), FM 25 (25% of SBM protein was substituted by LPFM) and FM 50 (50% of SBM protein was substituted by LPFM). Nine 55l circular plastic tanks were stocked by 12 fish to form three experimental groups. No differences in tilapia performance were observed between the control and the FM 25 diet. Chemical composition of fish did not differ significantly among treatments except for protein and selenium contents where the highest values were recorded in the control treatment. The highest mineral content was recorded in floc collected from the control tanks, while calcium content showed its highest value in floc collected from FM 50 effluent. These data indicate that replacing soybean meal with LPFM up to 25%, had no negative effect on growth performance and potentially may improve the system sustainability. Meanwhile, the adverse effect of more inclusion of LPFM in tilapia diet may be attributed to the higher content of ash. In other word, minerals seem to cause more energy utilization in fish fed floc meal since it is needed to maintain osmotic homeostasis.
The Wadi Watir delta in the Wadi Watir watershed is a tourist area in the arid southeastern part of the Sinai Peninsula, Egypt, where development and growth of the community on the delta are constrained by the amount of groundwater that can be withdrawn sustainably. To effectively manage groundwater resources in the Wadi Watir delta, the origin of groundwater recharge, groundwater age, and changes in groundwater chemistry in the watershed needs to be understood. Mineral identification, rock chemistry, water chemistry, and the isotopes of hydrogen, oxygen, and carbon in groundwater were used to identify the sources, mixing, and ages of groundwater in the watershed and the chemical evolution of groundwater as it flows from the upland areas in the watershed to the developed areas at the Wadi Watir delta. Groundwater in the Wadi Watir watershed is primarily from recent recharge while groundwater salinity is controlled by mixing of chemically different waters and dissolution of minerals and salts in the aquifers. The El Shiekh Attia and Wadi El Ain areas in the upper Wadi Watir watershed have different recharge sources, either from recharge from other areas or from different storm events. The downgradient Main Channel area receives groundwater flow primarily from the El Shiekh Attia area. Groundwater in the Main Channel area is the primary source of groundwater supplying the aquifers of the Wadi Watir delta. 相似文献
An alternative iron removal treatment method using liquid-liquid extraction with the room-temperature ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, as a solvent medium was studied. The chelating agent 1,10-phenanthroline was used as the extractant. The extraction of Fe(III) and Fe(II) was influenced significantly by the pH of the aqueous phase. The successful removal of iron was achieved; more than 95 % of the initial iron concentration was removed from the groundwater samples. However, detailed research is needed before the ionic liquid method can replace the conventional groundwater treatment protocol because the recovery rate was very low upon reuse (approximately 25–60 %). This low recovery was due to the ion exchange process; the appearance of anions from ionic liquids was also detected in groundwater samples. 相似文献