Ion exchange properties of oceanic ferromanganese nodules and enclosing pelagic sediments

Results of the experimental study of ion exchange properties of deep-sea pelagic sediments and related ferromanganese nodules (FMN) are considered. The exchange complex of sediments and nodules includes Na⁺, K⁺, Ca²⁺, and Mg²⁺ cations. The FMNs also include Mn²⁺ cations. Series of reactivity of metal cations during exchange reactions in different types of pelagic clayey sediments and diagenetic-sedimentary FMN are compiled. Series of exchange capacity of the sediments and FMN for alkali and heavy metal cations are also presented. The exchange capacity of FMN is always higher than that of enclosing sediments. Sediments are characterized by reversible equivalent sorption of cations of both alkali and heavy metals. Irrespective of the mineral composition, the FMNs are characterized by the reversible equivalent sorption of alkali metal cations, whereas sorption of heavy metal cations is only partly reversible. More over, alkali metal cations do not replace heavy metal cations. The results obtained refine the role of ion exchange processes in the redistribution of heavy metal cations at the water-bottom sediment interface during the diagenetic-sedimentary formation of ferromanganese nodules.     

Groundwater chemistry and occurrence of arsenic in the Meghna floodplain aquifer,southeastern Bangladesh

Dissolved major ions and important heavy metals including total arsenic and iron were measured in groundwater from shallow (25–33 m) and deep (191–318 m) tube-wells in southeastern Bangladesh. These analyses are intended to help describe geochemical processes active in the aquifers and the source and release mechanism of arsenic in sediments for the Meghna Floodplain aquifer. The elevated Cl⁻ and higher proportions of Na⁺ relative to Ca²⁺, Mg²⁺, and K⁺ in groundwater suggest the influence by a source of Na⁺ and Cl⁻. Use of chemical fertilizers may cause higher concentrations of NH₄⁺ and PO₄³⁻ in shallow well samples. In general, most ions are positively correlated with Cl⁻, with Na⁺ showing an especially strong correlation with Cl⁻, indicating that these ions are derived from the same source of saline waters. The relationship between Cl⁻/HCO₃⁻ ratios and Cl⁻ also shows mixing of fresh groundwater and seawater. Concentrations of dissolved HCO₃⁻ reflect the degree of water–rock interaction in groundwater systems and integrated microbial degradation of organic matter. Mn and Fe-oxyhydroxides are prominent in the clayey subsurface sediment and well known to be strong adsorbents of heavy metals including arsenic. All five shallow well samples had high arsenic concentration that exceeded WHO recommended limit for drinking water. Very low concentrations of SO₄²⁻ and NO₃⁻ and high concentrations of dissolved Fe and PO₄³⁻ and NH₄⁺ ions support the reducing condition of subsurface aquifer. Arsenic concentrations demonstrate negative co-relation with the concentrations of SO₄²⁻ and NO₃⁻ but correlate weakly with Mo, Fe concentrations and positively with those of P, PO₄³⁻ and NH₄⁺ ions.     

Nature of Co-bearing ferromanganese crusts of the Magellan Seamounts (Pacific Ocean): Communication 2. Ion exchange properties of ore minerals

The results of experimental studies of ion exchange properties of Co-bearing ferromanganese crusts in the Magellan Seamounts (Pacific Ocean) are discussed. Maximum reactivity in reactions with the participation of manganese minerals (Fe-vernadite, vernadite) is typical of Na⁺, K⁺, and Ca²⁺ cations, whereas minimum activity is recorded for cations Pb²⁺ and Co²⁺. The exchange complex of ore minerals in crusts is composed of Na⁺, K⁺, Ca²⁺, Mg²⁺, and Mn²⁺ cations. The exchange capacity of manganese minerals increases from the alkali metal cations to rare and heavy metal cations. Peculiarities of the affiliation of Co²⁺, Mn²⁺, and Mg²⁺ cations in manganese minerals of crusts are discussed. In manganese minerals, Co occurs as Co²⁺ and Co³⁺ cations. Metal cations in manganese minerals occur in different chemical forms: sorbed (Na⁺, K⁺, Ca²⁺, Mn²⁺, Co²⁺, Cu²⁺, Zn²⁺, Cd²⁺, and Pb²⁺); sorbed and chemically bound (Mg²⁺, Ni²⁺, Y³⁺, La³⁺, and Mo⁶⁺); and only chemically bound (Co³⁺). It is shown that the age of crust, its preservation time in the air-dry state, and type of host substrate do not affect the ion exchange indicators of manganese minerals. It has been established that alkali metal cations are characterized by completely reversible equivalent sorption, whereas heavy metal cations are sorbed by a complex mechanism: equivalent ion exchange for all metal cations; superequivalent, partly reversible sorption for Ba²⁺, Pb²⁺, Co²⁺, and Cu²⁺ cations, relative to exchange cations of manganese minerals. The obtained results refine the role of ion exchange processes during the hydrogenic formation of Co-bearing ferromanganese crusts.     

Characterization of PM10 in the ambient air during Deepawali festival of Rajnandgaon district, India

Deepawali is one of the main festivals for Hindu religion which falls in the period October–November every year with great fireworks display. In this study, we investigated the levels of water soluble ions and heavy metals—during the fireworks festival in Rajnandgaon, Central India. The chemical compositions and noise level distributions are reported from the sampling site. First time during Deepawali, air quality was studied in this area, The Aerosol samples of PM₁₀ (particle aerodynamic diameter <10 μm) are collected in October 24–28, 2011. Aims of the present studies are (1) To describe the particulate concentrations and associated chemical species during Deepawali festival, (2) To recognize the noise level in Deepawali festival. For study, the samples were collected in glass fiber filter paper and analyzed for the major water soluble ions F^?, Cl^?, NO₃ ^?, SO₄ ^2?, Na²⁺, NH₄ ⁺, K⁺, Ca²⁺, and Mg²⁺ employing ion chromatograph. Concentration of heavy metals was analyzed by ICP-MS and was observed to occur in order Fe > Zn > Pb > Ni > Cr > Cd. The result revels that all concentration are above the permissible limit fixed by CPCB, USPEA, and WHO standard. It is concluded that the burning of fireworks during Deepawali festival was the main source of heavy metals and ion.     

Water soluble components of PM10 Chongqing, China

The concentrations of water soluble ions (Na⁺, NH₄ ⁺, K⁺, Mg²⁺, Ca²⁺, NO₃ ^-, Cl^-, and SO ₄ ^2- ) in PM₁₀ samples collected on cellulose filters by a medium-volume cascade impactor were determined, which were obtained from three kinds of areas in Chongqing: industrial area (Jiulongpo district), commercial and residential area (Jiangbei district) and background area (Jinyun Mountain in the Beibei district). The results showed that except for the background site, the annual average values of PM₁₀ are 23% – 61% higher than the national air quality standard (GradeII) (0.1 mg/m³), even that the value of the control site is still 20% higher than American standard (0.05 mg/m³). This implied that serious pollution of fine particles occurred in Chongqing. Nine kinds of soluble ions in water of PM₁₀ were analyzed by ion chromatography (IC) and the annual average concentrations follow the order of [SO ₄ ^2- ] > [NO³ _-] > [Cl^-] > [F^-], and [Ca²⁺] > [NH₄ ⁺] > [K⁺] > [Na⁺] > [Mg²⁺]. Their values were different in these areas: the industrial area > the commercial and living area > the control area. As for NH_{4 +}, K⁺, Ca²⁺, NO₃ ^- and SO ₄ ^2- , their seasonal average concentrations show a similar variation trend: the values in spring and fall were higher than those in summer and winter. The seasonal average concentrations of [Cl^-], [F^-], [Na⁺] and [Mg²⁺] are much lower than those of other ions. However, the concentrations of [Na⁺] changed more greatly in different seasons than those of the other three ions. Correlation coefficients showed that the three areas have been polluted by coal smoke and dust to different extents, while some local resources of pollution should be taken into consideration as well.     

Hydrogeochemical investigation and groundwater quality assessment of Pratapgarh district,Uttar Pradesh

Hydogrochemical investigation of groundwater resources of Paragraph district has been carried out to assess the solute acquisition processes and water quality for domestic and irrigation uses. Fifty-five groundwater samples were collected and analyzed for pH, electrical conductivity, total dissolved solids, hardness, major anions (F^?, Cl^?, NO₃, HCO₃ ^?, SO₄ ^2?) and cations (Ca²⁺, Mg²⁺, Na⁺, K⁺). Study results reveal that groundwater of the area is alkaline in nature and HCO₃ ^?, Cl^?, Mg²⁺, Na⁺ and Ca²⁺ are the major contributing ions to the dissolved solids. The hydrogeochemical data suggest that weathering of rock forming minerals along with secondary contributions from agricultural and anthropogenic sources are mainly controlling the groundwater composition of Pratapgarh district. Alkaline earth metals (Ca²⁺+Mg²⁺) exceed alkalis (Na⁺+K⁺) and weak acid (HCO₃ ^?) dominate over strong acids (Cl^?+SO₄ ^2?) in majority of the groundwater samples. Ca-Mg-HCO₃ and Ca-Mg-Cl-HCO₃ are the dominant hydrogeochemical facies in the groundwater of the area. The computed saturation indices demonstrate oversaturated condition with respect to dolomite and calcite and undersaturated with gypsum and fluorite. A comparison of groundwater quality parameters in relation to specified limits for drinking water shows that concentrations of TDS, F^?, NO₃ ^? and total hardness exceed the desirable limits in many water samples. Quality assessment for irrigation uses reveal that the groundwater is good for irrigation. However, values of salinity, sodium adsorption ratio (SAR), residual sodium carbonate (RSC), %Na and Kelley index are exceeding the prescribed limit at some sites, demanding adequate drainage and water management plan for the area.     

Major ions chemistry of groundwater in the arid region of Zhangye Basin, northwestern China

As one of the most arid regions in the world, the study area, Zhangye Basin is located in the middle reaches of the Heihe River, northwest China. Besides aridity, rapid social and economic development also stimulates greater demand for water, which is gradually fulfilled by groundwater extraction. In this study, the conventional hydrochemical techniques and statistical analyses were applied to examine the major ions chemistry and hydrochemical processes of groundwater in the Zhangye Basin. The results of chemical analysis indicate that no one pair of cations and anions proportions is more than 50% in the groundwater samples of the study area. High-positive correlations were obtained among the following ions: HCO₃ ^?–Mg²⁺, SO₄ ^2?–Mg²⁺, SO₄ ^2?–Na⁺ and Cl^?–Na⁺. TDS depends mainly on the concentration of major ions such as HCO₃ ^?, SO₄ ^2?, Cl^?, Mg²⁺ and Na⁺. The hydrochemical types in the area can be divided into two major groups: the first group includes Mg²⁺–Na⁺–HCO₃ ^?, Mg²⁺–Na⁺–Ca²⁺–HCO₃ ^?–SO₄ ^2? and Mg²⁺–Ca²⁺–Na⁺–SO₄ ^2?–HCO₃ ^? types. The second group comprises Mg²⁺–Ca²⁺–SO₄ ^2? type, Mg²⁺–Ca²⁺–SO₄ ^2?–Cl^? type and Mg²⁺–Na⁺–SO₄ ^2?–Cl^? type. The ionic ratio plot and saturation index calculation suggests that the silicate weathering, to some extent, and evaporation are dominant factors that determine the major ionic composition in the study area.     

离子色谱法同时测定铀矿浸出液中的阳离子

对铬铁矿中亚铁的测定方法进行了探讨。首先对已有方法进行了验证和筛选,然后对Li2SO4助熔剂的助溶作用及其反应机理进行了研究,从而推荐了H2SO4-H3PO4-V2O5-V(Ⅳ)-Li2SO4和H2SO4-H3PO4-Ce(SO4)2-Li2SO4两种改进型的溶剂体系用于铬铁矿试样中亚铁的测定,所得结果具有良好的重现性。     

ZH型重金属螯合纤维对水溶液中Sr2+的吸附行为

研究了ZH型重金属螯合纤维对水溶液中Sr~(2+)的吸附行为,考察了pH值、纤维加入量、Sr~(2+)初始浓度、作用时间等对吸附行为的影响,并采用SEM、EDS和FTIR等现代分析测试手段探讨了ZH型重金属螯合纤维对Sr~(2+)的吸附机制。结果表明,在pH值为7.0、纤维加入量为2.0 g/L、Sr~(2+)初始质量浓度为50 mg/L的条件下,纤维对Sr~(2+)的吸附在4 h左右基本达到平衡。实验条件下ZH型重金属螯合纤维对Sr~(2+)的最大吸附量可达26.22 mg/g。等温吸附拟合结果表明,ZH型重金属螯合纤维对Sr~(2+)的吸附可能是以单分子层为主的单分子层和多分子层吸附共同作用的结果。纤维对Sr~(2+)的动力学吸附过程符合准二级动力学模型。红外光谱分析表明Sr~(2+)与纤维上—NH_2和—COOH等基团进行配位络合从而吸附在纤维表面,—CH_2—和C=CH_2等基团参与此吸附过程。能谱分析表明Sr~(2+)与纤维上Na~+和Ca~(2+)还存在着离子交换作用。     

Modelling Zn(II) sorption onto clayey sediments using a multi-site ion-exchange model

In environmental studies, it is necessary to be able to predict the behaviour of contaminants in more or less complex physico-chemical contexts. The improvement of this prediction partly depends on establishing thermodynamic models that can describe the behaviour of these contaminants and, in particular, the sorption reactions on mineral surfaces. In this way, based on the mass action law, it is possible to use surface complexation models and ion exchange models. Therefore, the aim of this study is (i) to develop an ion-exchange model able to describe the sorption of transition metal onto pure clay minerals and (ii) to test the ability of this approach to predict the sorption of these elements onto natural materials containing clay minerals (i.e. soils/sediments) under various chemical conditions. This study is focused on the behaviour of Zn(II) in the presence of clayey sediments. Considering that clay minerals are cation exchangers containing multiple sorption sites, it is possible to interpret the sorption of Zn(II), as well as competitor cations, by ion-exchange equilibria with the clay minerals. This approach is applied with success to interpret the experimental data obtained previously in the Zn(II)–H⁺–Na⁺–montmorillonite system. The authors’ research team has already studied the behaviour of Na⁺, K⁺, Ca²⁺ and Mg²⁺ versus pH in terms of ion exchange onto pure montmorillonite, leading to the development of a thermodynamic database including the exchange site concentrations associated with montmorillonite and the selectivity coefficients of Na⁺, K⁺, Ca²⁺, Mg²⁺, and Zn²⁺ versus H⁺.     

Chemistry and source identification of wet precipitation in a rural watershed of subtropical China

South China is one of the regions severely suffering from acid rain in the world.However,few systematic studies of rural precipitation chemistry have been performed in comparison with the extensive studies on their urban counterparts of this region.In order to characterize the current acid rain status and identify its possible sources in the rural area of South China,we analyzed precipitation collected event by event from a rural forested watershed in southern Anhui Province between March 2007 and February 2010.The results showed that the concentrations of major ions within precipitation in the studied rural area were significantly lower than those reported for the urban areas of the same latitude in China.Nevertheless,the precipitation acidity(with an average pH value of 4.49) and the frequency of acid rain(95%) were considerably high.The relatively high ratio of(SO42+ NO 3)/(Ca2+ +NH4+) was the main cause of acid rain in this rural area,as SO 2 and NO x were the main precursors of acid rain,while Ca2+ and NH4+acted as the dominant neutralizers to the acidity.Source identification indicated that Ca2+ and Mg2+ mainly were derived from alkaline dust,SO42,NO 3 and NH4+originated mainly from anthropogenic sources such as industrial and agricultural activities,most Na +,Cl,K + and some of Mg2+ were derived from the sea.The results suggested that the major ions within precipitation in the rural area of South China were related to the meso-scale and long-range transport of particles and aerosols in the air.     

Interstitial solutions and diagenesis in deeply buried marine sediments: results from the Deep Sea Drilling Project

Through the Deep Sea Drilling Project samples of interstitial solutions of deeply buried marine sediments throughout the World Ocean have been obtained and analyzed. The studies have shown that in all but the most slowly deposited sediments pore fluids exhibit changes in composition upon burial. These changes can be grouped into a few consistent patterns that facilitate identification of the diagenetic reactions occurring in the sediments.Pelagic clays and slowly deposited (<1 cm/10³yr) biogenic sediments are the only types that exhibit little evidence of reaction in the pore waters.In most biogenic sediments sea water undergoes considerable alteration. In sediments deposited at rates up to a few cm/10³ yr the changes chiefly involve gains of Ca²⁺ and Sr²⁺ and losses of Mg²⁺ which balance the Ca²⁺ enrichment. The Ca-Mg substitution may often reach 30 mM/kg while Sr²⁺ may be enriched 15-fold over sea water. These changes reflect recrystallization of biogenic calcite and the substitution of Mg²⁺ for Ca²⁺ during this reaction. The Ca-Mg-carbonate formed is most likely a dolomitic phase. A related but more complex pattern is found in carbonate sediments deposited at somewhat greater rates. Ca²⁺ and Sr²⁺ enrichment is again characteristic, but Mg²⁺ losses exceed Ca²⁺ gains with the excess being balanced by SO₄^{post staggered2?} losses. The data indicate that the reactions are similar to those noted above, except that the Ca²⁺ released is not kept in solution but is precipitated by the HCO₃^{post staggered?} produced in SO₄^{post staggered2?} reduction. In both these types of pore waters Na⁺ is usually conservative, but K⁺ depletions are frequent.In several partly consolidated sediment sections approaching igneous basement contact, very marked interstitial calcium enrichment has been found (to 5.5 g/kg). These phenomena are marked by pronounced depletion in Na⁺, Si and CO₂, and slight enhancement in Cl^?. The changes are attributed to exchange of Na⁺ for Ca²⁺ in silicate minerals forming from submarine weathering of igneous rocks such as basalts. Water is also consumed in these reactions, accounting for minor increases in total interstitial salinity.Terrigenous, organic-rich sediments deposited rapidly along continental margins also exhibit significant evidences of alteration. Microbial reactions involving organic matter lead to complete removal of SO₄^{post staggered2?}, strong HCO₃^{post staggered?} enrichment, formation of NH₄^{post staggered+}, and methane synthesis from H₂ and CO₂ once SO₄^{post staggered2?} is eliminated. K⁺ and often Na⁺ (slightly) are depleted in the interstitial waters. Ca²⁺ depletion may occur owing to precipitation of CaCO₃. In most cases interstitial Cl^? remains relatively constant, but increases are noted over evaporitic strata, and decreases in interstitial Cl^? are observed in some sediments adjacent to continents.     

Geochemistry and quality of groundwater of Gummanampadu sub-basin, Guntur District, Andhra Pradesh, India

Groundwater survey has been carried out in the area of Gummanampadu sub-basin located in Guntur District, Andhra Pradesh, India for assessing the factors that are responsible for changing of groundwater chemistry and consequent deterioration of groundwater quality, where the groundwater is a prime source for drinking and irrigation due to non-availability of surface water in time. The area is underlain by the Archaean Gneissic Complex, over which the Proterozoic Cumbhum rocks occur. The results of the plotting of Ca²⁺ + Mg²⁺ versus HCO₃ ^? + CO₃ ^2?, Ca²⁺ + Mg²⁺ versus total cations, Na⁺ + K⁺ versus total cations, Cl^? + SO₄ ^2? versus Na⁺ + K⁺, Na⁺ versus Cl^?, Na⁺ versus HCO₃ ^? + CO₃ ^2?, Na⁺ versus Ca²⁺ and Na⁺: Cl^? versus EC indicate that the rock–water interaction under alkaline condition is the main mechanism in activating mineral dissociation and dissolution, causing the release of Ca²⁺, Mg²⁺, Na⁺, K⁺, HCO₃ ^?, CO₃ ^2?, SO₄ ^2? and F^? ions into the groundwater. The ionic relations also suggest that the higher concentrations of Na⁺ and Cl^? ions are the results of ion exchange and evaporation. The influences of anthropogenic sources are the other cause for increasing of Mg²⁺, Na⁺, Cl^?, SO₄ ^2? and NO₃ ^? ions. Further, the excess alkaline condition in water accelerates more effective dissolution of F^?-bearing minerals. Moreover, the chemical data plotted in the Piper’s, Gibbs’s and Langelier–Ludwig’s diagrams, computed for the chloro-alkaline and saturation indices, and analyzed in the principal component analysis, support the above hypothesis. The groundwater quality is, thus, characterized by Na⁺ > Ca²⁺ > Mg²⁺ > K⁺: HCO₃ ^? + CO₃ ^2? > Cl^? > SO₄ ^2? > NO₃ ^? > F^? facies. On the other hand, majority of groundwater samples are not suitable for drinking with reference to the concentrations of TDS, TH, Mg²⁺ and F^?, while those are not good for irrigation with respect to USSL’s and Wilcox’s diagrams, residual sodium carbonate, and magnesium hazard, but they are safe for irrigation with respect to permeability index. Thus, the study recommends suitable management measures to improve health conditions as well as to increase agricultural output.     

Ion exchange properties of manganese and iron minerals in oceanic micronodules

The results of experimental studies of ion exchange properties of manganese and iron minerals in micronodules (MN) from diverse bioproductive zones of the World Ocean are considered. It was found that the sorption behavior of these minerals is similar to that of ore minerals from ferromanganese nodules (FMN) and low-temperature hydrothermal crusts. The exchange complex of minerals in the MN includes the major (Na⁺, K⁺, Ca²⁺, Mg²⁺, and Mn²⁺) and the subordinate (Ni²⁺, Cu²⁺, Co²⁺, Pb²⁺, and others) cations. Reactivity of theses cations increases from Pb²⁺ and Co²⁺ to Na⁺ and Ca²⁺. Exchange capacity of MN minerals increases from the alkali to heavy metal cations. Capacity of iron and manganese minerals in the oceanic MN increases in the following series: goethite < goethite + birnessite < todorokite + asbolane-buserite + birnessite < asbolane-buserite + birnessite < birnessite + asbolane-buserite < birnessite + vernadite Fe-vernadite + Mn-feroxyhyte. The data obtained supplement the available information on the ion exchange properties of oceanic ferromanganese sediments and refine the role of sorption processes in the redistribution of metal cations at the bottom (ooze) water-sediment interface during the MN formation and growth.     

Evaluation of trace-metal enrichments from the 26 December 2004 tsunami sediments along the Southeast coast of India

The tsunami sediments deposited after the December 2004 tsunami were sampled immediately in the coastal environment of Tamil Nadu State on the southeast coast of India. Fifty-four sediment samples were collected and 14 representative samples were selected to identify the level of metal contamination in tsunami sediments. The results indicate that the sediments are mainly of fine to medium-grained sand and contain significantly high contents of dissolved salts in sediments (Na⁺, K⁺, Ca⁺², Mg⁺², Cl⁻) in water-soluble fraction due to seawater deposition and evaporation. Correlation of acid leachable trace metals (Cr, Cu, Ni, Co, Pb, Zn) indicate that Fe-Mn oxyhydroxides might play an important role in controlling their association between them. Enrichment of trace metals is observed in all the locations with reference to the background samples. High values of trace metals in the southern part of the study area are due to the large-scale industries along the coast, and they are probably anthropogenic in nature and of marine origin, which could cause serious environmental problems.     

Major ion chemistry and metal distribution in coal mine pit lake contaminated with industrial effluents: constraints of weathering and anthropogenic inputs

Ion chemistry of mine pit lake water reveals dominance of alkaline earths (Ca²⁺ and Mg²⁺) over total cation strength, while SO₄ ^2? and Cl^? constitute the majority of total anion load. Higher value of Ca²⁺?+?Mg²⁺/Na⁺?+?K⁺ (pre-monsoon 5.986, monsoon 8.866, post-monsoon 7.09) and Ca²⁺?+?Mg²⁺/HCO₃ ^??+?SO ₄ ² (pre-monsoon 7.14, monsoon 9.57, post-monsoon 8.29) is explained by weathering of Ca?CMg silicates and dissolution of Ca²⁺-bearing minerals present in parent rocks and overburden materials. Silicate weathering supposed to be the major geological contributor, in contrast to bicarbonate weathering does a little. Distribution coefficient for dissolved metals and sorbed to surface sediments is in the order of Cd?>?Pb?>?Fe?>?Zn?>?Cu?>?Cr?>?Mn. Speciation study of monitored metals in surface sediments shows that Fe and Mn are dominantly fractionated in exchangeable-acid reducible form, whereas rest of the metals (Cr, Pb, Cd, Zn, and Cu) mostly in residual form. Cd, Pb, and Zn show relatively higher recalcitrant factor that indicates their higher retention in lake sediments. Factor loading of monitored physico-chemical parameters resembles contribution/influences from geological weathering, anthropogenic inputs as well as natural temporal factors. Ionic load/strength of lake water accounted for geochemical process and natural factors, while pollutant load (viz BOD, COD and metals, etc.) is associated with anthropogenic inputs through industrial discharge.     

Hydrogeochemical investigation and qualitative assessment of surface water resources in West Bokaro coalfield,India

A hydrogeochemical study of surface water of the West Bokaro coalfield has been undertaken to assess its quality and suitability for drinking, domestic and irrigation purposes. For this purpose, fourteen samples collected from rivers and ponds of the coalfield were analysed for pH, conductivity, total dissolved solids (TDS), major cations (Ca²⁺, Mg²⁺, Na⁺ and K⁺), major anions (HCO₃^-, F^-, Cl^-, SO₄^2- and NO₃^-) and trace metals. The pH of the analysed water samples varied from 7.3 to 8.2, indicating slightly alkaline in nature. The electrical conductivity (EC) value varied from 93 μs cm^-1 to 906 μs cm^-1 while the TDS varied from 76 mg L^-1 to 658 mg L^-1. HCO₃^- and SO₄^2- are the dominant anion and Ca²⁺ and Na⁺ the cation in the surface water. The concentration of alkaline earth metals (Ca²⁺ + Mg²⁺) exceed the alkali metals (Na⁺ + K⁺) and HCO₃^- dominates over SO₄^2- + Cl^- concentrations in the majority of the surface water samples. Ca²⁺ -Mg²⁺ -HCO₃^- and Ca²⁺ -Mg²⁺ -Cl^- are the dominant hydrogeochemical facies in the surface water of the area. The water chemistry is mainly controlled by rock weathering with secondary contribution from anthropogenic sources. For quality assessment, analyzed water parameter values compared with Indian and WHO water quality standard. In majority of the samples, the analyzed parameters are well within the desirable limits and water is potable for drinking purposes. However, concentrations of TDS, TH, Ca²⁺, Mg²⁺ and Fe are exceeding the desirable limits in some water samples and needs treatment before its utilization. The calculated parameters such as sodium absorption ration, percent sodium, residual sodium carbonate, permeability index and magnesium hazard revealed good to permissible quality and suitable for irrigation purposes, however, higher salinity, permeability index and Mg-ratio restrict its suitability for irrigation at few sites.     

玉龙雪山地区大气降水中粉尘颗粒物特征研究

以在玉龙雪山地区采集的大气降水样品为主要研究载体,分析了大气降水中粉尘颗粒物随时间的变化特征和影响大气降水中粉尘含量的潜在因素. 结果表明：大气降水中颗粒物浓度和典型粉尘特征化学离子含量的变化具有很好的一致性,且季风期末大气降水中的微粒含量显著升高,显示了明显的季节性变化特征. 丽江市和甘海子盆地大气降水中粉尘化学离子含量(SO₄^2-,Mg²⁺,Ca²⁺,K⁺,NH₄⁺,NO₃^-,粉尘浓度)之间具有较好的相关性,反映了这些离子共同的来源. 降水中pH值和电导率的变化很大程度上受到粉尘活动的影响,海盐气溶胶粒子对玉龙雪山地区大气降水中典型粉尘微粒(除Cl^-和部分Na⁺之外)的沉降没有贡献. 此外,降水化学和微粒分析表明,丽江市区的大气环境不排除人为活动的影响.     

Assessment of groundwater quality of Lokoja basement area, North-Central Nigeria

The hydrochemical characteristics and quality of groundwater in Lokoja basement area have been evaluated based on different indices for assessing groundwater for drinking and irrigation purposes. Twenty groundwater samples were collected and analyzed for physicochemical parameters, major ions and heavy metals. The results revealed that the groundwater is slightly alkaline, with little variations in chemical composition. For example, electrical conductivity (EC) ranges from 242μS/cm to 1835μS/cm. The abundance of the major ions is in the order of Ca²⁺ >Na⁺>Mg²⁺>K⁺> Fe^2+/3+ = HCO₃ >Cl^? >NO₃ >SO₄ >PO₄. Based on the hydrochemical data, four hydrochemical facies were identified namely, Ca-Mg-HCO₃, Na-K-HCO₃, Na-K-Cl-SO₄ and Ca-Mg-Cl-SO₄ and these facies depict groundwater recharge zone, transition flow zone, deep flow zone and mixed water zone respectively. Groundwater from the area is unsuitable for drinking and domestic purposes as some of the ions and heavy metals of health concerns are well above the stipulated guideline values. Irrigation water quality indicators (salinity, Na % and Mg %), reveal that the groundwater is unsuitable for irrigation purposes. Interpreted statistical analysis reveals that the groundwater chemical compositions are controlled predominantly by weathering of litho units of the basement rocks and by drainage from domestic wastes.     

Hydrogeochemical processes and quality assessment of groundwater in Dumka and Jamtara districts, Jharkhand, India

The hydrogeochemical study of groundwater in Dumka and Jamtara districts has been carried out to assess the major ion chemistry, hydrogeochemical processes and groundwater quality for domestic and irrigation uses. Thirty groundwater samples were collected and analyzed for pH, electrical conductivity, total dissolved solids (TDS), total hardness, anions (F^?, Cl^?, NO₃ ^?, HCO₃ ^?, SO₄ ^2?) and cations (Ca²⁺, Mg²⁺, Na⁺, K⁺). The analytical results show the faintly alkaline nature of water and dominance of Mg²⁺ and Ca²⁺ in cationic and HCO₃ ^? and Cl^? in anionic abundance. The concentrations of alkaline earth metals (Ca²⁺?+?Mg²⁺) exceed the alkali metals (Na⁺?+?K⁺) and HCO₃ ^? dominates over SO₄ ^2??+?Cl^? concentrations in the majority of the groundwater samples. Ca?CMg?CHCO₃ is the dominant hydrogeochemical facies in 60?% of the groundwater samples, while 33?% samples occur as a mixed chemical character of Ca?CMg?CCl hydrogeochemical facies. The water chemistry is largely controlled by rock weathering and ion exchange processes with secondary contribution from anthropogenic sources. The inter-elemental correlations and factor and cluster analysis of hydro-geochemical database suggest combined influence of carbonate and silicate weathering on solute acquisition processes. For quality assessment, analyzed parameter values were compared with Indian and WHO water quality standards. In majority of the samples, the analyzed parameters are well within the desirable limits and water is potable for drinking purposes. Total hardness and concentrations of TDS, Cl^?, NO₃ ^? _, Ca²⁺ and Mg²⁺ exceed the desirable limits at a few sites, however, except NO₃ ^? all these values were below the highest permissible limits. The calculated parameters such as sodium adsorption ratio, percent sodium (%Na) and residual sodium carbonate revealed excellent to good quality of groundwater for agricultural purposes, except at few sites where salinity and magnesium hazard (MH) values exceeds the prescribed limits and demands special management.