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1.
Through systematic sampling and analysis of water and soil in the planning area of Langfang City, employing national environmental quality standards, the qualities of groundwater and surface-water was overall evaluated. On the whole, the quality of deep-level groundwater was better and hazardous substances were not superstandard, F is higher, Fe and Mg was superstandard in several sites. The quality of shallow groundwater was general worse and COD, Fe, Mn, NH4^+-N, F, total hardness, total dissolved solids etc. overstep drinking water standard; the quality of surface water was worst and many indices were evidently higher, which was very worst in the east of downtown. Main pollution way of water body was lixiviation type of primary pollution groundwater and infiltration type of secondary pollution groundwater. Environmental quality assessment of plough layer soil indicated that it was better in the northwest and worse in the southeast, furthermore from Xiwu, Daguanzhang, Zhougezhuang to Pengzhuang, Dazhaolin and the north of Jingshan railroad, the environmental quality is worst.  相似文献   

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The small and medium-sized river basins along southeast coast of China hold comparatively abundant water resources. However, the rapid resources urbanization in recent years has produced a series of water problems such as deterioration of river water quality, water shortage and exacerbated floods, which have constrained urban economic development. By applying the principle of triple supply-demand equilibrium, this paper focuses on the estimation of levels of water supply and demand in 2030 at different guarantee probabilities, with a case study of Xiamen city. The results show that water shortage and inefficient utilization are main problems in the city, as the future water supply looks daunting, and a water shortage may hit nearly 2 × 108 m3 in an extraordinarily dry year. Based on current water supply-demand gap and its trend, this paper proposes countermeasures and suggestions for developing and utilizing groundwater resources and improving the utilization rate of water resources, which can supply as a reference for other southeast middle-to-small-sized basin cities in terms of sustainable water resources and water environment protection.  相似文献   

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Water samples from precipitation, glacier melt, snow melt, glacial lake, streams and karst springs were collected across SE of Kashmir Valley, to understand the hydrogeochemical processes governing the evolution of the water in a natural and non-industrial area of western Himalayas. The time series data on solute chemistry suggest that the hydrochemical processes controlling the chemistry of spring waters is more complex than the surface water. This is attributed to more time available for infiltrating water to interact with the diverse host lithology. Total dissolved solids (TDS), in general, increases with decrease in altitude. However, high TDS of some streams at higher altitudes and low TDS of some springs at lower altitudes indicated contribution of high TDS waters from glacial lakes and low TDS waters from streams, respectively. The results show that some karst springs are recharged by surface water; Achabalnag by the Bringi stream and Andernag and Martandnag by the Liddar stream. Calcite dissolution, dedolomitization and silicate weathering were found to be the main processes controlling the chemistry of the spring waters and calcite dissolution as the dominant process in controlling the chemistry of the surface waters. The spring waters were undersaturated with respect to calcite and dolomite in most of the seasons except in November, which is attributed to the replenishment of the CO2 by recharging waters during most of the seasons.  相似文献   

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The arrested, prograde amphibolite- to granulite-facies transition at Kabbaldurga, south India, overprints Archacan amphibolite-facies nebulitic gneisses and the late Archaean Closepet granite. Previous studies have shown that this facies transition was controlled by a channelled influx of a dehydrating fluid, assumed to be CO2, at 750°C and 5.5 kbar confining pressure. The effect of this type of prograde transition on zircon U–Pb isotopic systematics and whole-rock geochemistry has been studied using 1 kg amphibolite-facies, transitional and granulite-facies domains from a single block of gneiss. The zircon populations from all three domains have essentially similar morphology and U–Pb systematics. This similarity shows that at the conditions under which the prograde granulite-facies transition took place via fluid influx, the zircon U–Pb systematics were not disturbed by the process. Using the pooled data from all three domains, it is concluded that the protolith of the gneiss formed at 2965±4 Ma (2), and that zircons also grew during an anatectic event common to all domains at 2528±5 Ma. The granulite-facies metamorphism has not been dated directly due to the lack of response to the zircon U–Pb isotopic systematies to it. However, field and petrographic criteria dictate that its maximum age is 2528±5 Ma, the age of the anatectic event common to each domain in the gneiss block, which was overprinted during the granulite-facies event. For most major and trace elements, consistent enrichment or depletion trends associated with the transition to granulite facies cannot be identified with confidence. However, the granulite-facies portion is LREE (light-rare-earth-element)-enriched and H (heavy) REE-depleted compared with the amphibolite-facies domain, and the transitional domain is at intermediate values. The isotopic and geochemical evidence presented supports the conclusion that the granulite-facies charnockitic rocks at Kabbaldurga were not formed by removal of an anatectic melt, but that they formed later by simple metamorphic overprint of amphibolite-facies rocks.  相似文献   

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Following complaints about water shortages in some areas of Gweru, the paper assessed the availability of enabling capacities to efficiently and sufficiently deliver water to the residents of Gweru in line with the existing level of demand. The key inspected capacity aspects were infrastructure, human resources, finances and physical availability of raw water at source. Purposively selected informants from Zimbabwe National Water Authority (ZINWA) and Gweru city council (GCC) provided data on the infrastructural, financial and human resources situation of GCC. Dam levels data for Gweru’s three supply dams were obtained from ZINWA records through the assistance of Sanyati Catchment Hydrologist. The raw water availability was assessed with the aid of Mann–Kendall test using a 10 years period data set from 2003 to 2012 for trend analysis. Findings revealed that the water sources were not experiencing major changes in water levels, to be precise, the changes were insignificant. However, given the increase in population and demand, any slightest negative change in the supply chain would further widen the gap between supply and demand. The study also uncovered that GCC had challenges in terms of the infrastructure, mainly due to financial constraints. Notably, GCC was not experiencing high staff turnover, but it was however, seriously under staffed and failing to effectively monitor water use in the city. Therefore, strong financial injection is required to support staff and resuscitate the reticulation system. Given the perpetual water shortages in Gweru and the status quo in the supply chain, water demand management strategies, wastewater use and consumer education are consequently proposed as measures that would ensure continuous water supply for all needs in the city.  相似文献   

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Background: With development of intensive agriculture in the agricultural regions of the Northern provinces (Caspian Sea coasts), which involves frequent pesticide use in highly mechanized cash-crop cultures. To investigate and provide information on pest…  相似文献   

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Although numerous papers have been published on nutrients in Great Lakes, estuaries, continental shelf areas and marines in the aspects of determination, sediment-water-interface exchange, fluxes and budget estimation, eutrophication and microbial processes as well as modeling study, the knowledge of river condition (especially urban river) is uncertain and simply considered as a contributor to eutrophication of estuary. After a series of determinations of nitrogen species corresponding to ammonia-N (AN), Kjeldahl-N (K-N), and total nitrogen (TN) by means of National Standards for China, the nitrate & nitrite (Nitr-N) and org-N were obtained by the difference of TN with K-N, and K-N with AN, respectively. Therefore, the behaviors of vertical distributions in overlying waters and porewaters in the Fu and Nan Rivers located in Chengdu City were achieved.  相似文献   

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The paper presents original authors' data on the O, H, C, S, and Sr isotopic composition of water and sediments from the basins into which the Aral Sea split after its catastrophic shoaling: Chernyshev Bay (CB), the basin of the Great Aral in the north, Lake Tshchebas (LT), and Minor Sea (MS). The data indicate that the δ18О, δD, δ13C, and δ34S of the water correlate with the mineralization (S) of the basins (as of 2014): for CB, S = 135.6‰, δ18О = 4.8 ± 0.1‰, δD = 5 ± 2‰, δ13C (dissolved inorganic carbon, DIC) = 3.5 ± 0.1‰, δ34S = 14.5‰; for LT, S = 83.8‰, δ18О = 2.0 ± 0.1‰, δD =–13.5 ± 1.5‰, δ13C = 2.0 ± 0.1‰, δ34S = 14.2‰; and for MS, S = 9.2‰, δ18О =–2.0 ± 0.1‰, δD =–29 ± 1‰, δ13C =–0.5 ± 0.5‰, δ34S = 13.1‰. The oxygen and hydrogen isotopic composition of the groundwaters are similar to those in MS and principally different from the artesian waters fed by atmospheric precipitation. The mineralization, δ13С, and δ34S of the groundwaters broadly vary, reflecting interaction with the host rocks. The average δ13С values of the shell and detrital carbonates sampled at the modern dried off zones of the basins are similar: 0.8 ± 0.8‰ for CB, 0.8 ± 1.4‰ for LT, and –0.4 ± 0.3‰ for MS. The oxygen isotopic composition of the carbonates varies much more broadly, and the average values are as follows: 34.2 ± 0.2‰ for CB, 32.0 ± 2.2‰ for LT, and 28.2 ± 0.9‰ for MS. These values correlate with the δ18O of the water of the corresponding basins. The carbonate cement of the Late Eocene sandstone of the Chengan Formation, which makes up the wave-cut terrace at CB, has anomalously low δ13С up to –38.5‰, suggesting origin near a submarine methane seep. The δ34S of the mirabilite and gypsum (11.0 to 16.6‰) from the bottom sediments and young dried off zone also decrease from CB to MS in response to increasing content of sulfates brought by the Syr-Darya River (δ34S = 9.1 to 9.9‰) and weakening sulfate reduction. The 87Sr/86Sr ratio in the water and carbonates of the Aral basins do not differ, within the analytical error, and is 0.70914 ± 0.00003 on average. This value indicate that the dominant Sr source of the Aral Sea is Mesozoic–Cenozoic carbonate rocks. The Rb–Sr systems of the silicate component of the bottom silt (which is likely dominated by eolian sediments) of MS and LT plot on the Т = 160 ± 5 Ma, I0 = 0.7091 ± 0.0001, pseudochron. The Rb–Sr systems of CB are less ordered, and the silt is likely a mixture of eolian and alluvial sediments.  相似文献   

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The Quaternary Aquifer of the North China Plain is one of the worlds largest aquifer systems and supports an enormous exploitation of groundwater, which has reaped large socio-economic benefits in terms of grain production, farming employment and rural poverty alleviation, together with urban and industrial water-supply provision. Both population and economic activity have grown markedly in the past 25 years. Much of this has been heavily dependent upon groundwater resource development, which has encountered increasing difficulties in recent years primarily as a result of aquifer depletion and related phenomena. This paper focuses upon the hydrogeologic and socio-economic diagnosis of these groundwater resource issues, and identifies strategies to improve groundwater resource sustainability.
Resumen El acuífero cuaternario de la Llanura Septentrional de China es uno de los mayores sistemas acuíferos del mundo y soporta una enorme explotación de su agua subterránea, las cuales han originado grandes beneficios socioeconómicos en términos de producción de grano, empleo en agricultura y mitigación de la pobreza rural, además de proveer agua para abastecimiento urbano e industria. Tanto la población como la actividad económica han crecido mucho en los últimos 25 años con una gran dependencia de las aguas subterráneas, que ha encontrado dificultades recientes por la explotación intensiva del acuífero y fenómenos relacionados. Este artículo se centra en la diagnosis hidrogeológica y socioeconómica de los problemas relacionados con las aguas subterráneas e identifica estrategias para mejorar la sustentabilidad de este recurco.

Résumé Laquifère Quaternaire de la Plaine du Nord de la Chine est lun des plus grands systèmes aquifères du monde; il permet une exploitation énorme deau souterraine, qui a permis des très importants bénéfices socio-économiques en terme de production de céréales, demplois ruraux et de réduction de la pauvreté rurale, en même temps que lapprovisionnement en eau potable et pour lindustrie. La population comme lactivité économique ont remarquablement augmenté au cours de ces 25 dernières années. Elles ont été sous la forte dépendance du développement de la ressource en eau souterraine, qui a rencontré des difficultés croissantes ces dernières années, du fait du rabattement de laquifère et des phénomènes associés. Cet article est consacré aux diagnostiques hydrogéologique et socio-économique des retombées de cette ressource en eau souterraine; il identifie les stratégies pour améliorer la pérennité des ressources en eau souterraine.
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Petrographic and geochemical data on the sandstones of the Proterozoic intracratonic Kaladgi–Badami basin, southern India are presented to elucidate the palaeoweathering pattern, and composition and tectonics of their provenance. The Kaladgi–Badami basin, hosting the Kaladgi Supergroup, occupies an E–W trending area. The Supergroup unconformably overlies Archaean basement TTG gneisses, granites and greenstones, comprises a cyclic arenite–pelite–carbonate association and is divided into the Bagalkot and Badami Groups. The immature arkosic character of the basal Saundatti Quartzite Member (Bagalkot Group) containing fresh and angular feldspars, along the northern margin of the basin, suggests that during the initial stage of deposition, this part of the basin received sediments from a restricted, uplifted and less weathered source dominated by K-rich granites occurring to the north. In contrast, the Saundatti Quartzite along the southern margin displays a mostly mature, quartz-rich character with less abundant but severely weathered feldspars, and higher SiO2 and CIA but lower Al2O3, TiO2, Rb, Sr, Ba, K2O, K2O/Na2O, Zr/Ni and Zr/Cr. This is interpreted in terms of a tectonically stable, considerably weathered mixed source (Archaean gneisses, granites and greenstones) along the southern fringe of the basin. The highly mature (quartz arenite) Muchkundi Quartzite Member (also of the Bagalkot Group), occurring higher up in the succession, exhibits minor but severely altered feldspars, and higher SiO2, Na2O, CIA, Cr and Ni with lower K2O, Al2O3, TiO2 and K2O/Na2O. This reflects that with the passage of time the source evolved to a uniform, extensively weathered, tectonically stable peneplained provenance which consisted of less evolved TTG gneisses and greenstones. This was followed by closure, deformation and upliftment of the basin hosting the Bagalkot Group and subsequent deposition of the Badami Group. Sandstone Members of this younger Group (Cave-Temple Arenite and Belikhindi Arenite) range widely in mineralogy (quartz arenite to arkose) and chemistry (including CIA), and point to a source that varied from uplifted, less weathered K-rich granites to less evolved, peneplained TTG gneisses and greenstones or even Bagalkot sediments. Variable alteration of feldspars in the Kaladgi sandstones and severe depletion of Ca, Na and Sr in the associated shales indicate a humid tropical (tropical and subtropical) climate facilitating chemical weathering.  相似文献   

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Water inrush into coal mines from aquifers underlying coal seams often causes serious casualties and economic losses. The key to preventing the disaster is to discover a water inrush mechanism suitable for specific geological and hydrogeological conditions and apply reasonable control measures. A case of the Chensilou mine is studied in this paper. Complex geological and hydrogeological conditions, such as 12 aquifers in the floor and small distance between coal seam and aquifer, make the mining face in the synclinal basin have a great risk of water inrush. In addition, as an important way to prevent the disaster, grouting will aggravate the risk of water inrush from the floor. The slurry will drive groundwater in the limestone aquifers L8, even L7 and L6 along the horizontal (fracture zone in L11~L8) and vertical (Fs1 ~Fd1) water flow channel into the mining face and synclinal basin. A new water inrush mechanism driven by grouting is formed. In order to prevent this disaster, based on statistical law of hole deviation, the relative error of vertical depth and the angle between the borehole and the rock formation are obtained. Finally, an improved grouting method is proposed, which is useful to ensure the safe production of coal mine and reduce the cost of grouting.  相似文献   

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As the diversion dike of the Middle Route of the South to North Water Transfer Project (MRSNWTP), the water quality and water quantity of Danjiangkou Reservoir is critical to the project. At present, the rates of industrial wastewater treatment and sewage discharge, which belongs to Chinese State Standard in the districts near the reservoir except Shiyan city, are less than 60% and 40% respectively. The point source pollutants will be controlled because of the project after some time, but the non-point source pollutants caused by vegetation degradation and water-soil erosion will not be controlled effectively in a long time. Water samples were collected from the Danjiangkou Reservoir during 2004 and 2005 and analyzed for trace metals, i.e., silver (Ag), aluminum (Al), arsenic (As), barium (Ba), bismuth (Bi), calcium (Ca), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), potassium (K), lithium (Li), magnesium (Mg), manganese (Mn), molybdenum (Mo), sodium (Na), nickel (Ni), lead (Pb), antimony (Sb), selenium (Se), silicon (Si), strontium (Sr), vanadium (V), zinc (Zn), chemicophysical parameters and nutrients, i.e., temperature (T), pH, dissolved oxygen (DO), turbidity, total suspended solid (TSS), nitrate/ammonia/ammonium-nitrogen (NO3^-/NH3/NH4^+-N), total nitrogen (TN), dissolved inorganic nitrogen (DIN), total phosphorus (TP), potassium permanganate index (IMn), biochemical oxygen demand (BOD), dissolved inorganic carbon (HCO3^-). Our results are water quality belongs to Chinese standard level II, trace metals are low, but they are accumulating, and many of which, i.e., As, Pb, will endanger reservoir water security.  相似文献   

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The Everglades (Florida, USA) is one of the world’s larger subtropical peatlands with biological communities adapted to waters low in total dissolved solids and nutrients. Detecting how the pre-drainage hydrological system has been altered is crucial to preserving its functional attributes. However, reliable tools for hindcasting historic conditions in the Everglades are limited. A recent synthesis demonstrates that the proportion of surface-water inflows has increased relative to precipitation, accounting for 33% of total inputs compared with 18% historically. The largest new source of water is canal drainage from areas of former wetlands converted to agriculture. Interactions between groundwater and surface water have also increased, due to increasing vertical hydraulic gradients resulting from topographic and water-level alterations on the otherwise extremely flat landscape. Environmental solute tracer data were used to determine groundwater’s changing role, from a freshwater storage reservoir that sustained the Everglades ecosystem during dry periods to a reservoir of increasingly degraded water quality. Although some of this degradation is attributable to increased discharge of deep saline groundwater, other mineral sources such as fertilizer additives and peat oxidation have made a greater contribution to water-quality changes that are altering mineral-sensitive biological communities.  相似文献   

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The stable hydrogen and oxygen of lake, river, rain and snow waters were investigated to understand the water cycle characteristics of the drainage basin of Manasarovar Lake in Tibet. Both δD and δ 18O of river water are larger than those of lake water and the effect of altitude on both δD and δ 18O is not very significant. This phenomenon was suggested to occur because Manasarovar basin is located in Qinghai–Tibet Plateau which has low latitude, high altitude, abundant glaciers, thin air and intensive solar radiation, resulting in higher evaporation in lake water.  相似文献   

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