Effect of large-scale reservoir and river regulation/reclamation on saltwater intrusion in Qiantang Estuary

By using field salinity data recorded in the Qiantang Estuary for the nearly forty years (which covers the periods before and after the erection of a large-scale reservoir in the watershed and river regulation/reclamation in the estuary) and one-dimensional salt water intrusion modeling, it is shown that the salt water intrusion decreases caused by increased low water discharge for the reservoir, while the intrusion increases for the increased tidal range because of the river regulation/reclamation. The integrate result is that the saltwater intrusion decreases.

     

氯盐溶液中甲烷水合物高压分解条件及影响因素

向水合物储层注入盐类溶液是水合物常规开采技术之一,所以必须掌握储层压力条件下盐类溶液中水合物分解条件及其影响因素.本文研究了NaCl、MgCl2、CaCl2氯盐溶液中甲烷水合物分解条件,结果表明NaCl(2.0、1.0、0.5 mol·L-1)、MgCl2 (1.0、0.5 mol·L-1)和CaCl2 (1.0、0.5 mol·L-1)溶液中甲烷水合物的分解温度比纯水中分别降低了(4.8、2.4、1.0 K (NaCl))、(5.3、1.5 K (MgCl2))和(4.3、1.8 K (CaCl2)).以van der Waals 和Platteeuw 热力学模型为基础,结合电解质溶液中水的活度方程(Pitzer-Mayorga 方程),给出了氯盐溶液中水合物分解条件热力学模型,进而比较了模型计算值与实验值,结果显示两者非常吻合.分析表明,氯盐溶液中离子静电作用产生的水分子溶剂化效应和盐析效应降低了水的活度而导致水合物分解温度降低.     

Dispersive liquid–liquid microextraction with little solvent consumption combined with gas chromatography–mass spectrometry for the pretreatment of organochlorine pesticides in aqueous samples

Dispersive liquid–liquid microextraction with little solvent consumption (DLLME-LSC), a novel dispersive liquid–liquid microextraction (DLLME) technique with few solvent requirements (13 μL of a binary mixture of disperser solvent and extraction solvent in the ratio of 6:4) and short extraction time (90 s), has been developed for extraction of organochlorine pesticides (OCPs) from water samples prior to gas chromatography/mass spectrometry analysis. In DLLME-LSC, much less volume of organic solvent is used as compared to DLLME. The new technique is less harmful to environment and yields a higher enrichment factor (1885–2648-fold in this study). Fine organic droplets were formed in the sample solution by manually shaking the test tube containing the mixture of sample solution and extraction solvent. The large surface area of the organic solvent droplets increases the rate of mass transfer from the water sample to the extractant and produces efficient extraction in a short period of time. DLLME-LSC shows good repeatability (RSD: 4.1–9.7% for reservoir water; 5.6–8.9% for river water) and high sensitivity (limits of detection: 0.8–2.5 ng/L for reservoir water; 0.4–1.3 ng/L for river water). The method can be used on various water samples (river water, tap water, sea water and reservoir water). It can be used for routine work for the investigation of OCPs.     

Electrokinetic transport of a spherical gel-layer model particle: inclusion of charge regulation and application to polystyrene sulfonate

An electrokinetic gel-layer model of a spherical, highly charged colloid particle developed previously [S. Allison, J. Colloid Interface Sci. 277 (2004) 248], is extended in several ways. The charge of the particle is assumed to arise from deprotonation of acidic groups that are present, in uniform concentration, over a portion (or all) of the gel layer. Free energy considerations coupled with Poisson-Boltzmann theory are used to estimate how the local electrostatic environment of a charged gel layer alters the local pK(a) of the acidic groups. This modulation of the charge of the colloidal particle, or "charge regulation," can be significant even for colloidal particles with strongly acidic groups at moderate pH if the ambient salt concentration is low. The methodology is applied to the viscosity and electrophoretic mobility data of a particular polystyrene sulfonate latex over a broad range of monovalent salt (NaCl) concentration [M.J. Garcia-Salinas, F.J. de las Nieves, Langmuir 16 (2000) 715]. The experimental data can be accounted for by a gel layer model that decreases in thickness, but does not vanish, as the salt concentration is increased. Viscosity data provides valuable information about the degree of solvation of the colloidal particle and the thickness of the gel layer. The mobility data is best explained by a model in which only the outermost portion of the gel layer is charged. Charge regulation is significant at a monovalent salt concentration of 3 x 10(-3) mol/l and increases as the salt concentration decreases.     

Temporal evolution of the3H levels in the surface waters around the Almaraz Nuclear Power Plant

We have quantified the evolution during 1994 of the impact on the Tagus river of liquid releases of³H (51.3 TBq in the cited year), originating from the functioning of the Almaraz Nuclear Power Plant, and conditioned by the management of the cooling reservoir water. Taking into account, on the one hand, that tritiated water is hydrodynamically indistinguishable from untritiated water when both form part of the same mass of liquid, and, on the other, the practically null stratification and forced circulation of the water in the cited cooling reservoir, together with the hydrological fluxes interchanged between the said reservoir and the Tagus river (which is entirely regulated in the section under study and, because of prolonged drought, had a relatively small flow during the study period), we were able to model satisfactorily the temporal evolution of the³H activity in the cooling reservoir.     

Types of saltwater intrusion of the Changjiang Estuary

The Changjiang Estuary is characterized by multi-order bifurcations, unsteady sub-merged sandbars, mid-channel sandbars, creeks and riffles. The following four types of saltwater intrusion are found: (1) direct intrusion from the sea; (2) intrusion during tidal flooding; (3) intrusion from tidal flats overflow; and (4) salt water coming upstream through other waterways. These result in a complicated temporal and spatial salinity distribution. A high chlorinity concentration zone exists from the Liuhekou to the Sidongkou along the South Branch. The salinity during neap tide or ordinary tide is higher than during spring tide.     

Types of saltwater intrusion of the Changjiang Estuary

The Changjiang Estuary is characterized by multi-order bifurcations, unsteady submerged sandbars, mid-channel sandbars, creeks and riffles. The following four types of saltwater intrusion are found: (1) direct intrusion from the sea; (2) intrusion during tidal flooding; (3) intrusion from tidal flats overflow; and (4) salt water coming upstream through other waterways. These result in a complicated temporal and spatial salinity distribution. A high chlorinity concentration zone exists from the Liuhekou to the Sidongkou along the South Branch. The salinity during neap tide or ordinary tide is higher than during spring tide.     

Analysis of aquatic‐phase natural organic matter by optimized LDI‐MS method

The composition and physiochemical properties of aquatic‐phase natural organic matter (NOM) are most important problems for both environmental studies and water industry. Laser desorption/ionization (LDI) mass spectrometry facilitated successful examinations of NOM, as humic and fulvic acids in NOM are readily ionized by the nitrogen laser. In this study, hydrophobic NOMs (HPO NOMs) from river, reservoir and waste water were characterized by this technique. The effect of analytical variables like concentration, solvent composition and laser energy was investigated. The exact masses of small molecular NOM moieties in the range of 200–1200 m/z were determined in reflectron mode. In addition, spectra of post‐source‐decay experiments in this range showed that some compounds from different natural NOMs had the same fragmental ions. In the large mass range of 1200–15 000 Da, macromolecules and their aggregates were found in HPO NOMs from natural waters. Highly humic HPO exhibited mass peaks larger than 8000 Da. On the other hand, the waste water and reservoir water mainly had relatively smaller molecules of about 2000 Da. The LDI‐MS measurements indicated that highly humic river waters were able to form large aggregates and membrane foulants, while the HPO NOMs from waste water and reservoir water were unlikely to form large aggregates. Copyright © 2014 John Wiley & Sons, Ltd.     

顶空固相微萃取-气相色谱-质谱联用测定饮用水中的2-甲基异莰醇和土臭素

2-甲基异莰醇(2-methylisoborneol, 2-MIB)和土臭素(geosmin, GSM)在水源水中大量分泌排放是造成饮用水土霉异味突发事件、引发居民用水恐慌的重用因素之一。使用顶空固相微萃取(HS-SPME)与气相色谱-质谱联用技术(GC-MS)建立了水库水、水库附近土壤、居民自来水中2-MIB和GSM的测定方法。结合正交分析优化了加盐量、萃取温度、萃取时间条件,在电子轰击(EI)-选择离子扫描(SIM)模式下进行了目标物的定性定量分析。结果表明:在5~1000 ng/L范围内,2-MIB和GSM的色谱峰面积与其质量浓度的线性关系良好(r²≥0.998), 2-MIB与GSM的检出限分别为0.72 ng/L和0.34 ng/L,定量限分别为2.40 ng/L和1.13 ng/L;目标物加标水平为10~600 ng/L时,平均回收率为93.6%~107.7%,相对标准偏差(RSD)≤6.1%(n=6)。基于上述方法,对辽宁省某地区水库水、水库附近土壤、居民自来水中的目标物进行检测,结果表明:水库水目标物质量浓度范围为3.0~3.6 ng/L,水库附近土壤中提取的2-MIB为8.1 ng/L、提取的GSM为17.8 ng/L,居民自来水中的目标物未检出。该方法操作简便、准确可靠,灵敏度高,无需有机溶剂,适合于饮用水中2-MIB和GSM的分析检测。     

Dispersive liquid–liquid microextraction using an in situ metathesis reaction to form an ionic liquid extraction phase for the preconcentration of aromatic compounds from water

A novel microextraction method is introduced based on dispersive liquid–liquid microextraction (DLLME) in which an in situ metathesis reaction forms a water-immiscible ionic liquid (IL) that preconcentrates aromatic compounds from water followed by separation using high-performance liquid chromatography. The simultaneous extraction and metathesis reaction forming the IL-based extraction phase greatly decreases the extraction time as well as provides higher enrichment factors compared to traditional IL DLLME and direct immersion single-drop microextraction methods. The effects of various experimental parameters including type of extraction solvent, extraction and centrifugation times, volume of the sample solution, extraction IL and exchanging reagent, and addition of organic solvent and salt were investigated and optimized for the extraction of 13 aromatic compounds. The limits of detection for seven polycyclic aromatic hydrocarbons varied from 0.02 to 0.3 μg L⁻¹. The method reproducibility produced relative standard deviation values ranging from 3.7% to 6.9%. Four real water samples including tap water, well water, creek water, and river water were analyzed and yielded recoveries ranging from 84% to 115%.      

A rapid, sensitive and effective quantitative method for simultaneous determination of cationic surfactant mixtures from river and municipal wastewater by direct combination of single-drop microextraction with AP-MALDI mass spectrometry

A rapid, simple, sensitive, and effective quantitative method for simultaneous determination of cationic surfactants (CS(+)) from river and municipal wastewater by direct combination of single-drop microextraction (SDME) with atmospheric pressure (AP)-MALDI mass spectrometry has been successfully demonstrated without the requirements of tedious sample pre- or post-treatment or separation by high-performance liquid chromatography (HPLC), gas chromatography (GC), and capillary electrophoresis (CE). This quantitative method can greatly enhance the signal-to-noise ratio for analysis of small molecules of CS(+) owing to the strong suppression of matrix ions by the analytes. In addition, SDME assisted in the isolation and preconcentration of CS(+) from water samples, which could effectively reduce the background interferences from the matrices present in waste and river water. The SDME conditions were optimized for achieving high extraction efficiency of CS(+) from aqueous samples, in terms of solvent selection, stirring speed, extraction time, exposure volume of acceptor phase, and salt addition. The enrichment factors for CS(+) were found to be 40-64-folds for 7 min of extraction time with no salt addition and at room temperature. This method was found to yield a linear calibration curve in the concentration range from 50 to 1500 microg/l CS(+) with a limit of detection (LOD) of 10 microg/l. The relative recoveries in river and municipal wastewater were found to be 93.8-103.6% and 91.0-98.7%, respectively. These results indicate that the combination of SDME with AP-MALDI/MS is effective for the simultaneous determination of CS(+) from river and municipal wastewater. In addition, a comparison of enrichments and LOD values for this method with hollow-fiber liquid phase microextraction (HF-LPME) was also demonstrated. The present approach is easy to operate, rapid, sensitive, and suitable for high-throughput of analysis.     

Simultaneous determination of triclosan,triclocarban, and transformation products of triclocarban in aqueous samples using solid‐phase micro‐extraction‐HPLC‐MS/MS

The presence of triclosan and triclocarban, two endocrine‐disrupting chemicals and antimicrobial agents, and transformation products of triclocarban, 1,3‐di(phenyl)urea, 1,3‐bis(4‐chlorophenyl)urea and 1,3‐bis(3,4‐dichlorophenyl)urea, in tap water, treated household drinking water, bottled water, and river water samples were investigated using solid‐phase micro‐extraction coupled with‐HPLC‐MS/MS, a rapid, green, and sensitive method. Factors influencing the quantity of the analytes extracted onto the solid‐phase micro‐extraction fiber, such as addition of salt, sample pH, extraction time, desorption time, and sample volume, were optimized using solid‐phase micro‐extraction‐HPLC‐MS/MS. The results showed that the method gave satisfactory sensitivities and precisions for analyzing sub‐part‐per‐trillion levels of triclosan, triclocarban, and transformation products of triclocarban in samples collected locally. The recoveries of analytes ranged from 97 to 107% for deionized water samples, and 99 to 110% for river water samples, and limits of detection were in the range of 0.32–3.44 and 0.38–4.67 ng/L for deionized water and river water samples, respectively. On average, the daily consumption of triclosan and triclocarban by an adult by consuming 2 liters of different types of drinking water were estimated to be in the range of 6.13–425 ng/day as a result of the concentrations of triclosan and triclocarban measured in this study.     

Polyelectrolyte conductivity

Using the de Gennes scaling model for the configuration of a polyelectrolyte chain in semidilute solution, we construct a simple model of AC conductivity for semidilute solutions of strongly charged polyelectrolytes without added salt. We compare the predictions of this model with literature data and new data on two polyelectrolytes with very different affinities for water. The sodium salt of sulfonated polystyrene in water is a hydrophobic polyelectrolyte (the uncharged monomer does not dissolve in water), where the chain is locally collapsed. The sodium salt of poly(2-acrylamido-2-methylpropanesulfonate), is a much more hydrophilic polyelectrolyte, making the chain quite expanded locally. The model describes the conductivity of both cases reasonably for concentrations below 10⁻² M (mol of monomer per liter). Deviations between experiment and theory at higher concentrations lead us to conclude that counterion condensation decreases as concentration is increased. This is qualitatively consistent with the experimental observation that the dielectric constant of the polyelectrolyte solution increases as polyelectrolyte is added. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2951–2960, 1997     

Application of a Cation-Exchange Membrane to Determine Cations of Trace Metals in River Water

Donnan-membrane-equilibrium graphite-furnace atomic-absorption spectrophotometry (DME-GFAAS) has been developed to determine cations of trace metals in river water. The method employs a cation-exchange membrane to separate metal cations from their complexes; both total and cationic forms of metals were determined by means of GFAAS. The sensitivity of the method for the measurement of trace metal cations is determined by the detection limits of GFAAS for the metals of interest. Comparable concentrations of metal cations in water from NBS and from the Erhjen river were obtained between the DME-GFAAS and calculated (WATEQ4F) methods, indicating that the developed method is promising for natural fresh waters. The effect of pH on the distribution of metal cation in the NBS river water is significant for Cu and Pb; concentrations of these cations increase with decreasing pH. However, the concentrations of Cd and Zn cations do not vary with pH except that the concentration of the Zn cation decreases significantly as the pH value increases beyond 9. The method was applied to measure the capacity of complexing Cu in Chung-Lu river water, which was estimated to be 2.3 μM.     

Sequence comparison and environmental adaptation of a bacterial endonuclease

The periplasmic/extracellular bacterial enzyme endonuclease I was chosen as a model system to identify features that might be responsible for temperature- and salt adaptation. A statistical study of amino acid sequence properties belonging to endonuclease I enzymes from three mesophilic habitats (non-marine, brackish water and marine), and three marine temperature groups (psychrophile, intermediate and mesophile) has been conducted. Ten new endonuclease I genes have been sequenced in order to increase the sample size. A bioinformatical method of property dependent statistical analysis of alignments has been applied. To our knowledge this is the first time these methods have been used in order to investigate environmental adaptation of enzymes. Adaptation to low temperature seems to involve increased surface isoelectric point and hydrophobicity in contrast to salt adaptation in which the isoelectric point and hydrophobicity at the surface decreases. Redistribution of charge and hydrophobicity might be the most important signature for cold adaptation and salt adaptation of this enzyme class. The results indicate that general trends of adaptation are possible to elucidate from the amino acid sequences. Also in this paper a new scale of stratified B-factors, derived from the Protein Data Bank, is presented.     

Salt water bathing prior to UVB irradiation leads to a decrease of the minimal erythema dose and an increased erythema index without affecting skin pigmentation

The combination of salt water baths and solar radiation is known as an effective treatment for patients with psoriasis and atopic dermatitis. To determine whether increased susceptibility to UVB radiation may contribute to this therapeutic effect we have studied the effect of bathing the skin in salt water prior to UVB irradiation. Twelve subjects were phototested on the volar aspects of their forearms with increasing doses of UVB radiation. One forearm was exposed to 5% salt water prior to irradiation. The minimal erythema dose (MED) was determined and the erythema index and skin pigmentation were assessed by photometric measurement. The combination of salt water bath and irradiation yielded a significant decrease of the MED when compared to UVB alone (median 90 mJ/cm2 vs 130 mJ/cm2, P < 0.01). Analysis of variance showed a significant influence of salt water bath on erythema (P < 0.05) but not on skin pigmentation. Within the MED test area the erythema index of the salt water exposed forearms was elevated significantly (P < 0.05) while skin pigmentation was not affected. Thus, bathing the skin in salt water leads to a decreased threshold level for the elicitation of UVB-induced erythema and a selective increase of the erythemal response. This sensitization to the effects of shortwave UVB radiation may increase immunosuppressive effects of UVB radiation and may lead to an increased efficacy of UVB phototherapy. However, there is also an increased sunburn risk when salt water baths are followed by exposure to UV radiation.     

耐温抗盐驱油聚合物溶液黏弹性

对3种不同结构类型的耐温抗盐驱油聚合物〔高分子量聚丙烯酰胺(HPAM)、磺化聚丙烯酰胺(S-HPAM)和疏水缔合聚丙烯酰胺(A-HPAM)〕的溶液黏弹性能进行了研究。在温度85℃下,通过稳态剪切和动态剪切试验,考察了质量浓度和矿化度对聚合物溶液黏弹性的影响。结果表明,随剪切速率增加,溶液表观黏度逐渐降低。质量浓度越高,溶液的储能模量(G')和损耗模量(G″)越大。由动态剪切实验数据,计算得到第一法向应力差(N1)。随质量浓度增加,聚合物溶液的N1逐渐增大;随矿化度增加,聚合物溶液的N1出现不同盐敏感区域,说明不同结构类型的驱油聚合物溶液对矿化度的弹性响应不同。研究结果为高温高盐油藏聚合物驱剂的选择及开发提供了理论参考。     

Heavy-metal pollution and its state in algae in Kakehashi river and Godani river at the foot of Ogoya mine, Ishikawa Prefecture.

Alga as Achnanthes minutissima among diatoms is a widely adaptable taxon on the state of an aquatic environment. In this study, it was found that diatom had a specific tolerance to heavy metals (Cu, Zn, Pb, and Cd etc.) in river water samples, because the diatom assemblage consisted of almost only Achnanthes minutissima in Kakehashi river and Godani river, which were polluted with waste water from Ogoya copper mine. The relationship between the concentrations of heavy metals (Cu, Zn, Pb and Cd) in river water and the attached substances (algae and silt etc.) and the relative abundances of diatom taxa were investigated in detail. The results indicated that the higher is the concentration of heavy metals in the river environment, the higher is only the relative abundances of Achnanthes minutissima. Thus, the taxon can be used as a bioindicator of heavy metal pollution. The relative rates of toxic chemical forms of copper in algae were 61 - 92% in the attached substances and 49-70% in the sediment on the river bed, respectively. Therefore, it was found that diatom as Achnanthes minutissima had a tolerance to heavy metals in river water, being able to live in such an environment. Since the water treated with calcium hydroxide from the deposition reservoir of Ogoya mine enters in Godani river, the river is polluted by heavy metals (Cu, Zn, Pb and Cd etc.). From the viewpoint of both biological and chemical analyses, Godani river is still polluted with heavy metals, because their concentrations in the river samples were very high. On the other hand, in Kakehashi river, the concentrations of heavy metals were very low and the distributions of some diatoms appeared in an unpolluted Nishimata river were observed. Therefore, Kakehashi river seems to be considerably recovered from heavy-metal pollution after closing the Ogoya mine.     

Effect of sodium salicylate and other electrolytes on the partition of 1-pentanol between sodium dodecylsulfate micelles and water: A gas-chromatographic study

The salt effect of sodium salicylate (NaS) on the micellization and micellar solubilization of sodium dodecylsulfate (NaDS) has been studied. The experimental and theoretical conditions for the determination of the thermodynamic partition coefficient P of 1-pentanol between the micellar pseudo-phase and water in presence of added salt is discussed in the case of a precise gas-chromatographic method. In Particular, it is shown that P decreases with solute concentration in aqueous NaDS and sodium perfluorooctanoate surfactant solutions in opposition to the classical behavior in water-organic immiscible phases. As a reference salt effect, it is shown that P is constant with added NaCl in a large salt concentration domain where NaDS micelles are known to undergo dranatic structural changes. In the case of added NaS, P decreases slightly at very high salt concentration. It is suggested that this behavior might be the consequence of partial mixed micelle formation between the salicylate ion and NaDS micelles.     

Photometric determination of dissolved oxygen with iron(II) cacotheline oxalate blue

Iron (II)-cacotheline-oxalate blue solution is used as reductometric reagent for the estimation of dissolved oxygen. By titrating the blue complex solution photometrically, the dissolved oxygen in water samples can be accurately determined in the range of 2 to 8 mg/l. The stoichiometry of the reaction between dissolved oxygen and the blue complex was found to be 1:0.8 or 5:4. The applicability of this method to distilled water, river water and reservoir water was tested.The Winkler's method [1] and its various modifications and adaptations, widely used for the determination of dissolved oxygen, are laborious and time consuming. Therefore a new method using iron (II)-cacotheline-oxalate (ICO) blue solution was developed for this purpose.