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1.
As investigations carried out in an immersion basin of a sauna, with rinsed-off sweat and in indoor and outdoor swimming-baths have shown, from the total of 702 ± 529 mg/urea released per bather there are released 37.06 ± 24.75 mg through the skin into water; hence a urine introduction of 30 … 35 ml per bather resulting. The urea concentration in the bathing water does not show any correlation with the NH+4-concentration and the COD-Mn. Although urea-degrading bacteria are present with concentrations of up to 1 ± 105 colonies/ml, there does not occur any enzymatic decomposition of urea in the bathing water. Nitrification was not detected in the bathing water, either. The use of urea as a hygienic quality criterion for bathing water is not regarded as necessary: the determination of the NH+4-concentration suffices as an indicator of the pollution with faecal matter and the bound effective chlorine. 相似文献
2.
Thermokarst lakes play a key role in the hydrological and biogeochemical cycles of permafrost regions. Current knowledge regarding the changes caused by permafrost degradation to the hydrochemistry of lakes in the Qinghai-Tibet Plateau (QTP) is limited. To address this gap, a systematic investigation of thermokarst lake water, suprapermafrost water, ground ice, and precipitation was conducted in the hinterland of the QTP. The thermokarst lake water in the QTP was identified to be of the Na-HCO3-Cl type. The mean concentrations of HCO3− and Na+ were 281.8 mg L−1 (146.0–546.2 mg L−1) and 73.3 mg L−1 (9.2–345.8 mg L−1), respectively. The concentrations of Li+, NH4+, K+, F−, NO2−, and NO3− were relatively low. Freeze-out fractionation concentrated the dissolved solids within the lake water during winter, which was deeply deepened on lake depth and lake ice thickness. Owing to solute enrichment, the ground ice was characterized by high salinity. Conversely, repeated replenishment via precipitation led to lower solute concentrations in the ground ice near the permafrost table compared to that within the permafrost. Although lower solute concentration existed in precipitation, the soil leaching and saline ground ice melting processes enhanced the solute load in suprapermafrost water, which is considered an important water and solute resource in thermokarst lakes. The influencing mechanism of permafrost degradation on thermokarst lake hydrochemistry is presumably linked to: (1) the liberation of soluble materials sequestered in ground ice; (2) the increase of solutes in suprapermafrost water and soil pore water; and (3) the changes in lake morphometry. These results have major implications on the understanding of the effects of ground ice melting on ecosystem functions, biogeochemical processes, and energy balance in a rapidly changing climate. 相似文献
3.
Fawzia AI-Ruwaih 《Ground water》1984,22(4):412-417
Chemical studies have been carried out on a number of water wells from the Dibdiba Formation northeast of Kuwait. Water salinity of this formation ranges between 3,300 mg/l to 7,000 mg/l, increasing with depth. The water entrapped in Dibdiba Formation is mainly sodium chloride type which can be differentiated into three different groups according to the ranges of concentration of the main cations and anions. These groups are: (3331113) sodium chloride water type in which Cl > Na, group (3333113) sodium chloride water type in which Na > Cl. In both groups the sequence of dominant cations is Na > Ca > Mg. Group (3333111) sodium chloride water type has Na > Cl and the sequence of dominant cations is Na > Mg > Ca. Chemical ratios of Ca/Mg, Na/Cl, and C1/HCO3 were worked out for Dibdiba ground water. The ratio of Ca/Mg Dibdiba Formation ranges from 0.4 to 8.58, the ratio of Na/Cl ranges between 0.98 to 1.33, and the ratio of C1/HCO3 is 232. A plot of chemical analysis on a trilinear diagram shows that Dibdiba Formation ground-water chemical properties are dominated by alkalies (Na > Ca) and strong acid (Cl > SO4). Water chemistry may reflect the history of the flow path, indicating regional flow as shown by increasing Na+, Cl-, SO–4 and where Ca+, Mg+ achieve equilibrium. 相似文献
4.
曝气充氧对城市污染河道内源铵态氮释放的控制 总被引：3，自引：1，他引：2
以城市污染河道沉积物和上覆水为研究对象,利用模拟实验方法,探讨不同曝气充氧方式(水曝气EW、底泥曝气ES)对污染河道內源铵态氮(NH4+-N)释放的影响.研究结果发现:从间隙水和沉积物中NH4+-N的削减效果来看,底泥曝气均要优于水曝气;实验结束后,底泥曝气组沉积物与间隙水中NH4+-N含量分别减少63.39%和43.33%,水曝气组分别减少了7.54%和13.98%;从沉积物-水界面NH4+-N的扩散通量变化来看,水曝气组界面通量高于对照组,其变化规律与对照组相似;底泥曝气组沉积物-水界面NH4+-N扩散通量变化过程完全不同于其它两组,在整个试验周期内(除第5 d以外),底泥曝气组的通量低于水曝气组,在第15 d最低,为13.73 mg/(m2.d),仅为水曝气组和对照组的14.68%和19.93%,表明底泥曝气组沉积物NH4+-N的释放潜力低于水曝气组沉积物. 相似文献
5.
城市污染河道沉积物可提取态氮的提取方式比较 总被引：4，自引：0，他引：4
以城市污染河道——南京仙林大学城九乡河表层沉积物为研究对象,探讨沉积物常用提取剂(1 mol/L KCl、2 mol/L KCl、4 mol/L KCl和0.01 mol/L CaCl2)在不同液土比(5∶1、10∶1、50∶1和100∶1)条件下,对城市污染河道沉积物可提取态氮(NH4+-N、NO3--N)测定的影响.结果表明:KCl的提取效果要优于CaCl2,二者NH4+-N提取量分别为312.17～479.23、177.52～339.31 mg/kg,NO3--N提取量分别为4.49～21.56、4.25～8.53 mg/kg;可提取态氮提取量随液土比增高而增大,其中1 mol/L KCl组,液土比100∶1时NH4+-N和NO3--N提取量分别比液土比5∶1时增加41.97%和187.08%;NH4+-N提取量随提取剂浓度增高而增大,NO3--N随提取剂浓度增高而降低;采用1 mol/L KCl提取剂、液土比100∶1的组合联合提取城市污染河道沉积物中的NH4+-N、NO3--N,提取效果较好. 相似文献
6.
太湖草源性"湖泛"水域沉积物营养盐释放估算 总被引：22，自引：12，他引：10
于太湖草源性"湖泛"暴发期,采集柱状沉积物并应用peeper被动采样装置获得"湖泛"区原位沉积物间隙水.泥水样品分析表明:"湖泛"发生水域表层(0~7 cm)沉积物的含水率、孔隙度和有机质含量均明显高于对照区,其中有机质含量更是对照区样品的4倍左右,沉水植物残体促使表层沉积物物化性质改变的作用明显;"湖泛"发生水域表层沉积物间隙水中铵态氮(NH+4-N)、溶解性反应磷(SRP)及Fe2+含量远高于未发生区,植物残体降解对沉积物厌氧环境的营造显著.运用分子扩散模型对沉积物释放通量估算:"湖泛"发生区沉积物NH+4-N、SRP和Fe2+的释放速率分别是对照区的49.8、15.3和123.1倍.研究认为,草源性"湖泛"水体氮、磷等营养物含量升高的主要原因是沉积物的释放,而"湖泛"所营造的厌氧环境是氮、磷释放急剧增加的主要驱动因素. 相似文献
7.
Xiao Lin Mark J. McCarthy Stephen A. Carini Wayne S. Gardner 《Continental Shelf Research》2011,31(2):120-128
A new approach, combining 15NH4+ isotope dilution and continuous-flow techniques, provided estimates of “actual” and “net” NH4+ flux and sediment NH4+ demand (SAD) at the sediment-water interface (SWI) of sites in the northern Gulf of Mexico (NGOMEX). The sites included a hypoxic site (C6), two sites with intermediate oxygen levels (B7 and F5), and a normoxic site (CT). Control cores without isotope addition and other cores from the same site treated with 15NH4+ labeled overflowing water differentiated between net and actual regeneration flux and actual vs. potential uptake flux of NH4+. Experiments were conducted in 2008 before (July) and after (September) two successive hurricanes (Gustav and Ike) and in January and August, 2009. Actual regeneration was significantly higher than net flux at most sites. Net flux did not differ significantly in most sites/dates, but the actual regeneration, and the actual and potential uptake, showed temporal and spatial variation; the flux at the hypoxic site was more active than non-hypoxic sites. SAD, the difference between potential and actual NH4+ uptake flux, was higher at the hypoxic site than at non-hypoxic sites before and after the hurricanes in 2008 and during the hypoxia season in 2009. SAD related negatively to bottom water DO values. Conclusions: (1) net flux often underestimated actual regeneration, (2) hurricane activity decreased N dynamics, and (3) microbial N limitation status at the hypoxic site related to NH4+ removal processes that were independent of oxygen (e.g., anaerobic heterotrophic uptake or anammox). These results indicate a rather consistent NH4+ demand at the SWI during the hypoxic season and suggest that reduced nitrogen may limit microbial dynamics in the region. 相似文献
8.
《Physics and Chemistry of the Earth》2004,29(1):91-103
Pore water has been extracted from Boom Clay by mechanical squeezing. Clay cores were obtained from various boreholes, all drilled at the SCK·CEN domain (Mol, Belgium).In contrast to pore water collected from piezometers, high sulphate concentrations are measured in the squeezed pore water. The lowest sulphate concentrations (<60 mg/l) were measured in pore waters squeezed immediately after drilling. Higher sulphate concentrations were often measured in the pore water when the clay cores were preserved for some time (generally <500 mg/l SO42−, but sometimes up to 20,000 mg/l SO42−). Nevertheless, a relation between preservation time and sulphate content could not be retrieved. However, major ion concentrations were obviously correlated with the sulphate content in the squeezed waters. The observed evolution in chemical composition were explained by water–rock interactions considering the pyrite oxidation and the subsequent ion exchange and mineral dissolution reactions. 相似文献
9.
Materials of long-term studies of the concentration and distribution of N forms (NH4+, NO3−, NO2−, Norg) in precipitation, surface water and groundwater are generalized. Precipitation was found to be the main source of N compounds
input into these waters. The effect of anthropogenic factors is local and does not influence the concentration and distribution
of N forms in most water bodies that serve as wastewater recipients. The N forms dominating in precipitation are NO3− and N H4+; Norg dominates in most surface water bodies, and NO3− dominates in groundwater. The median concentrations of Ntot in clear surface and subsurface waters are similar. The obtained characteristics of the concentrations and distribution of
N forms in natural waters of Karelia can be used for other water bodies in the humid zone. 相似文献
10.
The effect of the overlying water velocity on ammonium (NH4+) uptake by benthic biofilms was studied in a recirculating laboratory flume (260 cm long, 29 cm wide), packed with 5 cm of silica sand arranged into bedforms. NH4+ uptake was determined as the reduction in NH4+ concentration in the water at average overlying water velocities of 0.8, 2, 4 and 8 cm s?1. NH4+ uptake was relatively constant under laminar flow conditions but increased when the flow regime became turbulent (>4 cm s?1). This pattern was observed for two biofilms differing in their total biomass and in the abundance of the ammonia‐oxidizing bacteria, thus indicating that NH4+ uptake was strongly controlled by mass‐transfer processes. The near stoichiometric relationship between the rates of NH4+ uptake and nitrate (NO3?) accumulation suggests that aerobic nitrification was the main route for NH4+ uptake. Microelectrode measurements showed a sharp decline of oxygen concentrations and pH values within the biofilms, thus supporting strong nitrification activity within the surficial section of the benthic biofilms. The results of this study highlight the key role of hydrodynamic conditions in regulating NH4+ uptake in the transition from laminar to turbulent flow conditions. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
11.
The persistence of inorganic nitrogen is assessed in a set of 21 septic system plumes located in Ontario, Canada, that were studied over a 31-year period from 1988 to 2019. In the plume zones underlying the drainfields, site mean NO3− values averaged 34 ± 27 mg N/L and exceeded the nitrate drinking water limit (DWL) of 10 mg N/L at 16 of 21 sites. In plume zones extending up to 30 m downgradient from the drainfields, site mean NO3− values averaged 24 ± 20 mg N/L and exceeded the DWL at 9 of 13 sites. Site mean total inorganic nitrogen (TIN; NH4+ + NO3− − N) removal averaged 34 ± 26% in the drainfield zones and 36 ± 44% in the downgradient plume zones, indicating that much of the removal occurred within the drainfields. Removal was much higher at nine sites where drainfield TIN included >10% NH4+ (62 ± 25% removal). TIN removal was not correlated with wastewater loading rate, system age, or sediment carbonate mineral content, but was correlated with water table depth, where shallower water table sites had generally less complete wastewater oxidation. At many of these sites, both NO3− and NH4+ were present together in the plumes and were lost concomitantly, suggesting that the anammox reaction was making an important contribution to the observed TIN loss. When groundwater nitrate contamination is a concern, considering on-site treatment system designs that lead to a lesser degree of wastewater oxidation, could be a useful approach for enhancing N removal. 相似文献
12.
This study analysed the importance of precipitation events from May 2003 to April 2004 on surface water chemistry and solute export from a 696 ha glaciated forested watershed in western New York State, USA. The specific objectives of the study were to determine: (a) the temporal patterns of solutes within individual storm events; (b) the impact of precipitation events on seasonal and annual export budgets; and (c) how solute concentrations and loads varied for precipitation events among seasons as functions of storm intensity and antecedent moisture conditions. Analysis of solute trajectories showed that NH4+, total Al and dissolved organic nitrogen (DON) peaked on the hydrograph rising limb, whereas dissolved organic carbon (DOC) concentrations peaked following the discharge peak. Sulphate and base‐cations displayed a dilution pattern with a minimum around peak discharge. End‐member mixing analysis showed that throughfall contributions were highest on the rising limb, whereas valley‐bottom riparian waters peaked following the discharge peak. The trajectories of NO3? concentrations varied with season, indicating the influence of biotic processes on the generation, and hence flux, of this solute. Storm events had the greatest impact on the annual budgets for NH4+, K+, total dissolved Al, DON and DOC. Storm events during summer had the greatest impact on seasonal solute budgets. Summer events had the highest hourly discharges and high concentrations of solutes. However, NO3? and DOC exports during a spring snowmelt event were considerably more than those observed for large events during other periods of the year. Comparisons among storms showed that season, precipitation amount, and antecedent moisture conditions affected solute concentrations and loads. Concentrations of solutes were elevated for storms that occurred after dry antecedent conditions. Seven of the largest storms accounted for only 15% of the annual discharge, but were responsible for 34%, 19%, 64%, 13%, 39% and 24% of the annual exports of NH4+, K+, Al, NO3?, DON and DOC respectively. These results suggest that the intense and infrequent storms predicted for future climate‐change scenarios will likely increase the exports of solutes like DOC, DON, NH4+, Al and K+ from watersheds. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
13.
不同水生植物对富营养化水体无机氮吸收动力学特征 总被引：3，自引：2，他引：1
采用浓度梯度法,研究了鸢尾(Iris louisiana)、狐尾藻(Myriophyllum verticillatum)、茭白(Zizania latifolia)和水芹(Oenanthe clecumbens)对硝态氮(NO3--N)和铵态氮(NH4+-N)吸收动力学特征.结果表明:4种水生植物对水体NO3--N和NH4+-N吸收可用Michaelis-Menten酶动力学方程描述,随溶液NO3--N和NH4+-N浓度增加,植物吸收NO3--N和NH4+-N速率增加,当溶液NO3--N和NH4+-N浓度接近于2.0 mmol/L时,吸收速率增加趋缓;4种水生植物对NO3--N和NH4+-N的Vmax值大小为水芹 >茭白 >鸢尾 >狐尾藻,对NO3--N的Km值大小为水芹 >鸢尾=茭白=狐尾藻,对NH4+-N的Km值大小为水芹 >狐尾藻 >茭白=鸢尾.根据吸收动力学参数(Vmax,Km)判断水芹适宜于净化NO3--N和NH4+-N浓度较高的水体,茭白、鸢尾和狐尾藻适合净化NO3--N和NH4+-N浓度较低水体;4种水生植物对NO3--N、NH4+-N表现出不同的吸收偏好性,鸢尾吸收NO3--N的潜力大于吸收NH4+-N的,但对NH4+-N的亲和力大于NO3--N,表明能在NO3--N浓度较高环境中优先吸收NH4+-N.狐尾藻和水芹对NO3--N和NH4+-N能均衡吸收.茭白对NH4+-N具有较高的吸收潜力与亲和力. 相似文献
14.
Wayne S. Gardner Mark J. McCarthy Stephen A. Carini Afonso C. Souza Hou Lijun Karen S. McNeal Mary Keith Puckett Jack Pennington 《Continental Shelf Research》2009,29(18):2207-2213
Settled particles of fresh, labile organic matter may be a significant source of oxygen demand and nutrient regeneration in seasonally-hypoxic regions caused by nutrient inputs into stratified coastal zones. Studying the dynamics of this material requires sediment sampling methods that include flocculent organic materials and overlying water (OLW) at or above the sediment–water interface (SWI). A new coring device (“HYPOX” corer) was evaluated for examining nitrogen- (N) and oxygen-dynamics at the SWI and OLW in the northern Gulf of Mexico (NGOMEX). The HYPOX corer consists of a “Coring Head” with a check-valve, a weighted “Drive Unit,” and a “Lander,” constructed from inexpensive components. The corer collected undisturbed sediment cores and OLW from sediments at NGOMEX sampling sites with underlying substrates ranging from sand to dense clay. The HYPOX corer could be deployed in weather conditions similar to those needed for a multi-bottle rosette water-sampling system with 20 L bottles. As an example of corer applicability to NGOMEX issues, NH4+ cycling rates were examined at hypoxic and control sites by isotope dilution experiments. The objective was to determine if N-dynamics in OLW were different from those in the water column. “Ammonium demand,” as reflected by potential NH4+ uptake rates, was higher in OLW than in waters collected from a meter or more above the bottom at both sites, but the pattern was more pronounced at the hypoxia site. By contrast, NH4+ regeneration rates were low in all samples. These preliminary results suggest that heterotrophic activity and oxygen consumption in OLW in the hypoxic region may be regulated by the availability of NH4+, or other reduced N compounds, rather than by the lack of sufficient labile organic carbon. 相似文献
15.
Thermal springs of the Boundary Creek hydrothermal system in the southwestern part of Yellowstone Park outside the caldera boundary vary in chemical and isotopic composition, and temperature. The diversity may be accounted for by a combination of processes including boiling of a deep thermal water, mixing of the deep thermal water with cool meteoric water and/or with condensed steam or steam-heated meteoric water, and chemical reactions with surrounding rocks. Dissolved-silica, Na+, K+ and Ca2+ contents of the thermal springs could result from a thermal fluid with a temperature of 200 ± 20°C. Chloride-enthalpy and silica-enthalpy mixing models suggest mixing of 230°C, 220 mg/l Cl− thermal water with cool, low-Cl− components. A 350 to 390°C component with Cl− ≥ 300 mg/l is possibly present in thermal springs inside the caldera but is not required to fit observed spring chemical and isotopic compositions. Irreversible mass transfer models in which a low-temperature water reacts with volcanic glass as it percolates downward and warms, can account for observed pH and dissolved-silica, K+, Na+, Ca2+ and Mg2+ concentrations, but produces insufficient Cl− or F− for measured concentrations in the warm springs. The ratio of aNa/aH, and Cl− are best accounted for in mixing models. The water-rock interaction model fits compositions of acid-sulfate waters observed at Summit Lake and of low-Cl− waters involved in mixing.The cold waters collected from southwestern Yellowstone Park have δD values ranging from −118 to −145 per mil and δ18O values of −15.9 to −19.4 per mil. Two samples from nearby Island Park have δD values of −112 and −114 per mil and δ18O values of −15.1 and −15.3 per mil. All samples of thermal water plot significantly to the right of the meteoric water line. The low Cl− and variable δD values of the thermal waters indicate isotopic compositions are derived by extensive dilution with cold meteoric water and by steam separation on ascent to the surface. Many of the hot springs with higher δD values may contain in addition a significant amount of high-D, low-Cl−, acid-sulfate or steam-heated meteoric water. Mixing models, Cl− content and isotopic compositions of thermal springs suggest that 30% or less of a deep thermal component is present. For example, the highest-temperature springs from Three Rivers, Silver Scarf and Upper Boundary Creek thermal areas contain up to 70% cool meteoric water and 30% hot water components, springs at Summit Lake and Middle Boundary Creek spring 57 are acid-sulfate or steam-heated meteoric water; springs 27 and 48 from Middle Boundary Creek and 49 from Mountain Ash contain in excess of 50% acid-sulfate water; and Three Rivers spring 46 and Phillips could result from mixing hot water with 55% cool meteoric water followed by mixing of acid-sulfate water. Extensive dilution by cool meteoric water increases the uncertainties in quantity and nature of the deep meteoric, thermal component. 相似文献
16.
Jean-François Maguer Stéphane L'HelguenJulien Caradec Cécile Klein 《Continental Shelf Research》2011,31(15):1620-1631
The effect of light on nitrate (NO3−) and ammonium (NH4+) uptake by natural communities was investigated in relation to cell size (<10 and >10 μm) in the well-mixed coastal waters of the English Channel. Nitrogen (N) uptake kinetics as a function of irradiance were assessed using 15N tracer techniques, for a seasonal cycle of populations collected at 50% and 1% light penetration depth. The nitrogen uptake responses to irradiance can be represented by the formulation used to describe the photosynthesis versus irradiance relationships and modified by the addition of a dark uptake parameter. The response curves of two size fractions of phytoplankton collected at 50% and 1% of incident light did not differ significantly, which suggested that the physiological characteristics of N uptake were not affected by the light intensity at which the phytoplankton assemblages were sampled. The kinetics parameters indicated that the NO3− uptake system was more strongly dependent on light than the NH4+ uptake system. They also showed that N uptake was less limited by the light intensity in the small size fraction than it was in the large size fraction. At the mean light intensity in the water column, kinetics analysis predicted a NH4+ uptake that was on average 1.8 (±0.6) and 2.4 (±1.0) times greater than the NO3− uptake, for <10 and >10 μm size fractions, respectively. The kinetics also predicted, at the in situ mean light intensity, that the mean ability to take up nitrogen was twice as high (1.8±0.5) for the small than for the large cells when the N substrate was NH4+ and more than twice as high (2.6±1.5) when the substrate was NO3−. These results added to our understanding of the light effect on N uptake processes in well-mixed waters, and can largely explain the phytoplankton production, mainly regenerated and dominated by small cells, that has been observed in these waters. 相似文献
17.
Elin Almroth Anders Tengberg Johan H. Andersson Svetlana Pakhomova Per O.J. Hall 《Continental Shelf Research》2009,29(5-6):807-818
The effect of resuspension on benthic fluxes of oxygen (O2), ammonium (NH4+), nitrate (NO3?), phosphate (PO43?), silicate (Si(OH)4), dissolved inorganic carbon (DIC), total dissolved iron (Fe) and total dissolved manganese (Mn) was studied at three different stations in the Gulf of Finland (GoF), Baltic Sea during three cruises in June–July 2003, September 2004 and May 2005. The stations were situated on different bottom types in the western, central and eastern part, respectively, of the open GoF. The fluxes were measured in-situ using the autonomous Göteborg benthic lander. To simulate resuspension events, the stirring speed was increased in two of the four chambers of the lander after approximately half of the incubation time. The other two chambers were used as control chambers. Clear effects of resuspension were observed on the oxygen fluxes where an increase of the consumption was observed in 88% of the cases and on average with 59% (stdev=53). The NH4+ fluxes were affected in 50% of the cases (4 out of 8 incubations) at stations with low bottom water oxygen concentrations, but in no cases where the bottom water was oxygenated (0 out of 9 incubations). The NH4+ fluxes decreased by 26±27% in 2005 and by 114±19% in 2003. There was no clear effect of resuspension on the fluxes of any of the other solutes in this study. Thus, resuspension events did not play a significant role in release/uptake of NO3?, PO43?, Si(OH)4, DIC, Fe and Mn in GoF sediments. However, increased oxygen consumption as a result of resuspension may lead to spreading of anoxic/suboxic bottom water conditions, and thus indirectly to increased benthic release of phosphate, ammonium and iron. 相似文献
18.
天津中心城区河网氮磷污染与富营养化特征 总被引：1，自引：0，他引：1
2013年底天津中心城区河道全部连通,形成中心城区河网.为了掌握河网形成后的水质状况,于2014年3月-2015年2月进行了为期1年的定点水质监测,并对其水体氮、磷时空分布及富营养化特征进行分析.结果表明,河网水体氮污染严重,以铵态氮(NH+4-N)为主;磷污染程度较轻,主要形态为磷酸盐(PO3-4-P);河网水体中氮、磷浓度顺水流方向均呈上游高、下游低的空间分布特征;氮、磷各项指标浓度时间变化趋势基本一致,3月均最高,10月均最低,冬季处于相对较低水平;与河网形成前相比,海河干流NH+4-N、总磷(TP)和PO3-4-P浓度年平均值分别下降6.5%、14.7%和16.4%,津河总氮、NH+4-N、硝态氮、TP和PO3-4-P浓度年平均值分别降低18.6%、34.5%、12.9%、31.6%和32.5%,表明河网形成后氮、磷污染程度较之前有所改善,其中津河改善较为明显;河网水体全年处于中度富营养状态,主要为磷限制性状态;河网富营养化防治应遵循以控制营养盐为主的控源、截污、水环境增容和生态补水策略. 相似文献
19.
高效净化氮磷污水的湿地水生植物筛选与组合 总被引：14，自引：2，他引：12
抚仙湖流域未进行生态修复的磷矿废弃地面积142×10^4m^2,对磷矿废弃地污染物流失量和区域内径流污染物含量进行调查观测,并提出磷矿废弃地水污染防治对策．富磷矿石剖面和堆土场在风化作用和降雨淋溶作用下,大量氟、磷等元素释放,造成磷矿区内地表径流和地下渗流污染结合实测的磷矿废弃地面积和土柱淋溶实验得到的污染物淋溶量,估算得到磷矿废弃地每年F和TP的淋溶流失量为60．65t／a和2734t／a,随地表径流迁移进入抚仙湖的F和TP分别为22．58t／a和7．27t／a由此可见,磷矿开采是抚仙湖的一个持久污染源,对湖泊营养化演变进程起了推动作用。 相似文献
20.
2010年10月-2011年9月在太湖梅梁湾围隔内研究了改性当地土壤絮凝除藻及其对水质改善的应急和长期效果,并结合室内实验研究了该技术防控底泥再悬浮和减少底泥二次污染的长效机制.现场围隔实验结果表明,改性当地土壤除藻30 min后,TN、NO3--N、NH4+-N、TP、PO34--P和Chl.a的去除率分别为66%、57%、60%、93%、92%和98%;长期监测结果表明,与对照区域相比,围隔内的TN、NH4+-N、NO3--N、TP和PO34--P在处理后11个月内的平均值分别降低了39.83%、52.30%、48.53%、18.75%和60.00%.室内再悬浮实验结果表明,改性土壤和沙子抗再悬浮能力较未改性土壤分别提高了3和5倍.室内柱培养结果表明改性土壤絮凝除藻和沙土覆盖相结合可有效提高表层沉积物-水界面的氧化还原电位和溶解氧,使沉积物向水体的TP和TN通量从源逆转成汇,PO34--P和NH4+-N通量大幅度降低.改性土壤技术在利用絮凝除藻快速改善水质后,可通过改性沙/土分层底泥调控分别达到对藻絮体再悬浮的物理控制和营养盐再释放的化学控制,通过将亚表层底泥中的藻细胞分解并被沉水植物根系吸收,可实现对底泥中水华蓝藻复苏和水体富营养化的长效生态控制. 相似文献