不同城镇功能区岩溶地下水化学敏感因子识别

随着西南地区城镇化进程的不断推进,西南城市区岩溶地下水环境压力迅猛增加,水质恶化显著。采集西南岩溶区四个典型城市（遵义市、桂林市、贵阳市和娄底市）的86组地下水样,运用描述性统计分析、变异系数分析及主成分分析法,综合研究了不同城镇功能区岩溶地下水化学特征及易受人类活动影响的敏感因子。结果表明,工业区岩溶地下水中电导率、总硬度、TDS、Na+、Mg2+、Cl -、SO2-4、NO-2、Mn这9项指标的含量均最高,商业住宅区次之,城乡结合处最低;而K+、NH+4和NO-3三者浓度表现为商业住宅区最高。研究区各地下水化学组分普遍具有较高的空间变异性,其中工业区易受人类活动影响的敏感因子为SO2-4、I-、Fe,商业住宅区易受人类活动影响的敏感指标为Na+、NO-2、NO-3,城乡结合处的主要敏感指标为Na+、Mg2+、NO-2。      

黄河源区阿尼玛卿山耶和龙冰川表层雪化学组成

2005年9月底, 在黄河源区阿尼玛卿山耶和龙冰川随海拔变化采集89个雪样, 分析了微粒和主要可溶无机离子(Na , K , Mg2 , Ca2 , NH 4, Cl-, NO-3, SO2-4)浓度以及δ18 O, 研究了各种物理化学指标在冰川中的时空分布特征. 结果表明: 大多数样品中主要阴、 阳离子当量摩尔浓度顺序为: NO-3>SO2-4>Cl-;Ca2 >NH 4>Na >Mg2 >K , 碳酸盐类物质是化学离子主要来源. 各种主要可溶离子有着明显的季节变化过程. 但由于融化再凝结过程, 不是所有离子在污化层浓度最大. 在所采样区域的表层雪中化学离子没有明显变化趋势, 指示局地物质的输入有限. 受降水量效应影响, 暖季δ18 O值低, 冷季高. 样品中, 9种离子被分为: 1)Ca2 , Mg2 和HCO-3～CO2-3;2)NH 4, SO2-4和Cl-;3)NO-3;4)Na , K 四个群组.     

湘西峒河流域水化学特征及无机碳通量计算

为了掌握亚热带季风气候岩溶地区流域水化学变化特征及量化流域内岩石化学风化过程对吸收大气CO2的贡献,文章选取湘西峒河流域作为研究对象,于2016年7—8月对研究区干流和7个子流域进行了水样采集与分析。结果表明:河水pH平均值为8.31,总体呈偏碱性。EC与TDS的变化范围较大,这主要与流域内岩性的分布有关。水中离子以Ca2+、HCO-3为主,水化学类型为HCO3—Ca型,岩性控制水化学的组成。HCO-3、Ca2+和Mg2+主要来源于碳酸盐岩的风化,其余离子来源多受人为活动影响。峒河流域干流的主要离子中,HCO-3、Ca2+和Mg2+浓度从上游至下游总体下降,反映了河流从碳酸盐岩区流向碎屑岩为主地层的过程。NO-3、K+、Na+、F-、Cl-和SO2-4呈增长趋势,说明峒河受人为污染影响较大,反映出人为活动的密集程度。通过子流域的划分可知流域上游主要受灰岩以及白云岩控制,中游以灰岩控制为主,下游受砂岩、泥岩及碎屑岩控制为主。收集流域最终出口吉首观测站一个水文年的数据并运用水化学—径流法估算出峒河流域无机碳通量为60 477.33 tCO2/a,碳汇强度为71.15 tCO2/（km2·a）。     

典型岩溶槽谷区地下水化学特征及地球化学敏感性分析

利用2012年4月—2013年3月的水化学数据研究了重庆老龙洞地下河流域地下水系统地球化学敏感性。结果表明,研究区表层岩溶泉和地下河水化学阳离子分别以Ca2+、Mg2+和Ca2+、Na+为主,阴离子以HCO3-、SO42-为主;表层岩溶泉雨季Mg2+/ Ca2+摩尔比和地下河雨季Na+/ Ca2+摩尔比旱季大于雨季,表层岩溶泉和地下河雨季 HCO3-/SO42- 摩尔比分别为3.428～6.524、3.122～5.966,旱季HCO3-/SO42-摩尔比分别为5.693～8.664、3.428～6.524,表现出低SO42-、高HCO3-的特征,主要受农业活动影响的表层岩溶泉主量元素地球化学敏感性依次为HCO3-> SO42->Ca2+> NO3-> Mg2+> Na+> K+>Cl-,而受农业活动、工业活动、城镇建设活动等多种因子共同影响下的地下河主量元素地球化学敏感性有所变化,依次为HCO3->Na+> Ca2+> K+> Cl-> Mg2+> NO3-> SO42-,随着人类影响的加剧,离子敏感指数将会有增加的趋势。      

大沽河流域上游水化学特征及其控制因素研究

大沽河流域是青岛市、烟台市重要的供水源区,为研究大沽河流域水化学特征及成因机制,选取大沽河流域上游补给区开展研究,采集35个地下水样品和5个地表水样品。综合运用描述性统计分析、Piper三线图、Gibbs图以及离子比值等方法,结合水文地质条件,分析研究区水化学特征,探索其水化学组成的成因机制。结果表明,大沽河流域地下水为弱碱性水,占优势的阴、阳离子分别为HCO-3、SO2-4和Ca2+、Mg2+。水化学类型共分多种,其中以HCO-3·SO2-4—Ca2+·Mg2+为主。大沽河流域水化学特征受水—岩作用、阳离子交换作用的影响,岩石风化溶解是水化学特征的主要控制因素,且阳离子交换作用活跃。Na+、K+、Cl-、偏硅酸主要来源于硅酸盐岩的溶解,Ca2+、Mg2+和SO2-4主要来源于碳酸盐岩的溶解,显著高于来自蒸发盐岩风化溶解的贡献。人类活动对地下水化学特征有较大影响,农业种植、养殖业等人类活动导致水中NO-3浓度普遍偏高,同时人类活动加剧了硅酸盐矿物的风化溶解,使得偏硅酸浓度升高,超过74%的水样偏硅酸质量浓度达到了25 mg/L。     

大沽河流域上游水化学特征及其控制因素研究

大沽河流域是青岛市、烟台市重要的供水源区,为研究大沽河流域水化学特征及成因机制,选取大沽河流域上游补给区开展研究,采集35个地下水样品和5个地表水样品。综合运用描述性统计分析、Piper三线图、Gibbs图以及离子比值等方法,结合水文地质条件,分析研究区水化学特征,探索其水化学组成的成因机制。结果表明,大沽河流域地下水为弱碱性水,占优势的阴、阳离子分别为HCO-3、SO2-4和Ca2+、Mg2+。水化学类型共分多种,其中以HCO-3·SO2-4—Ca2+·Mg2+为主。大沽河流域水化学特征受水—岩作用、阳离子交换作用的影响,岩石风化溶解是水化学特征的主要控制因素,且阳离子交换作用活跃。Na+、K+、Cl-、偏硅酸主要来源于硅酸盐岩的溶解,Ca2+、Mg2+和SO2-4主要来源于碳酸盐岩的溶解,显著高于来自蒸发盐岩风化溶解的贡献。人类活动对地下水化学特征有较大影响,农业种植、养殖业等人类活动导致水中NO-3浓度普遍偏高,同时人类活动加剧了硅酸盐矿物的风化溶解,使得偏硅酸浓度升高,超过74%的水样偏硅酸质量浓度达到了25 mg/L。     

贵州威宁窑上组沉积物物源特征及沉积控制因素分析

根据威宁草海第四纪窑上组沉积物主量元素和REE特征,探讨沉积物物源特征、气候演变情况、沉积物堆积控制因素。结果表明:Al、Mg、Ca、K、Na和Ti的含量变化在剖面上一致,它们的相关系数很高(0.522~0.985)。Fe含量和Mn含量呈正相关形式,与Al、Mg、Ca、K、Na和Ti呈负相关。Fe2O3含量在土黄色粘土的铁质层很高(42.86%~50.57%)。样品中REE球粒陨石标准化配分模式与贵州土壤、贵州碳酸盐岩风化壳配分模式很相似,与峨眉山玄武岩配分模式不一致,但其含量略低于贵州碳酸盐岩风化壳的含量;沉积物主要来源于碳酸盐岩,且碳酸盐岩强烈风化成土作用使REE超常富集,在剖面上呈现高ΣREE(平均219.38μg/g)。通过Mg/Ca、MgO/Al2O3、(CaO+K2O+Na2O)/Al2O3、(Fe2O3+Al2O3)/(MgO+CaO)、(K+Na+Ca+Mg)/(Fe+Mn)、(Al+Fe+Mn)/(K+Ca+Mg)和(MgO+Na2O+CaO)/Al2O3等气候指标研究,表明在草海窑上期为湖泊沉积时期,气候经历了由温暖湿润向冷干的转变。同时,认为物源性质、构造运动、气候等共同控制该区沉积物形成。     

黑龙江东宁金厂金矿土壤离子电导率异常特征、离子成份及找矿预测

为了解黑龙江东宁金厂金矿体土壤离子的电导率异常特征,查明金矿体中土壤离子电导率成分的离子组成以及不同种类离子的含量变化关系对电导率的贡献大小,初步探讨矿区土壤离子电导率异常的形成机理,本文对金厂金矿开展了土壤离子电导率测量,取得以下认识:(1)发现多个具有成矿远景的离子电导率异常区,经深部工程验证具有隐伏的金矿体;(2)组成土壤离子电导率异常的离子成分主要是HCO-3、SO2-4、Ca2+、Cl-、K+、Na+、F-、Mg2+、Mn2+等一套水可溶性离子,经过相关分析得出金矿电导率异常与各离子的相关系数为HCO-3>Ca2+>SO2-4>Cl->K+>Na+>F->Mg2+>Mn2+。     

矿井充水水源识别的EW-UCA模型及应用

迅速准确地识别矿井充水水源是防治矿井水害事故的重要保证。对未确知聚类方法进行优化,综合考虑水化学指标对水源识别的重要性,选取Na++K+、Mg2+、Ca2+、HCO-3、Cl-、SO2-4、TH等7项水化学指标作为水源识别的判别指标,以新庄孜煤矿22组水样数据作为训练样本,建立了矿井充水水源识别的EW-UCA模型。随后利用该模型对5组测试样本水样进行识别检验并与实际情况作了对比分析。为进一步检验识别模型的可靠度,利用该模型对谢一矿充水水源进行了识别研究。结果表明,EW-UCA水源识别模型具有较高的精确度和较强的适用性,可以在工程实际中推广应用。     

保定平原区地下水化学特征及演化

为揭示保定平原地下水水化学特征及演化规律,本文以保定平原为研究对象,对216组地下水样水化学特征进行了分析。综合运用Piper三线图、Gibbs图、相关离子分析等方法,研究了保定平原区深浅层地下水化学组成及水化学类型空间分布特征,识别了水化学形成机制与控制作用,在此基础上分析了水化学演化的成因。结果表明：沿地下水径流方向,浅层地下水与深层地下水主要离子含量呈现明显的递变规律,TDS、Na+、Mg2+、Cl-、SO2-4、HCO-3含量逐渐升高,K+、Ca2+逐渐降低,地下水优势阳离子Ca2+主导地位逐渐被Na+代替,优势阴离子HCO-3主导地位逐渐向Cl-过渡。地下水化学特征主要受水岩作用、阳离子交替吸附作用以及人类活动共同影响,水岩作用以碳酸盐岩和铝硅酸盐岩共同溶滤作用为主;浅层地下水受人类活动影响较大,影响离子主要为NO-3,集中分布于补给区,除了与农业活动相关外,主要与山前平原岩性颗粒粗,具有较强的渗透性有关。     

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.     

再生水入渗区典型抗生素分布特征与地下水微生物群落影响因素研究

再生水入渗携带的抗生素污染是地下水污染的来源之一,已经成为城市地下水资源的安全中不可忽视的问题。抗生素对复杂和脆弱地下水环境中的微生物群落及其功能的影响值得关注。本研究基于利用16S rRNA基因高通量测序方法,对3月和9月两个月份再生水渗入区城市地下水中微生物群落结构进行分析。结合现场调查测试和室内分析,测得样品中离子(K~+、Na~+、Ca²⁺、Mg²⁺、NH~+₄、F~-、Cl~-、SO■、NO~-₃、NO~-₂、HCO~-₃、CO■)浓度,并采用超高效液相色谱-串联质谱技术测得主要的抗生素浓度(环丙沙星、诺氟沙星、氧氟沙星、莫西沙星、磺胺吡啶和磺胺醋酰),对研究区地下水环境中微生物群落结构及与环境因子的响应规律进行探讨。结果表明：(1)研究区内3月份地下水中抗生素浓度要高于9月份整体抗生素浓度,以磺胺醋酰和环丙沙星为主,此外除了季节因素外,人类活动可能是影响抗生素分布的又一因素;(2)微生物群落主要由变形菌门(Proteobacteria,81.0...     

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.     

多种矿物流体包裹体中液相阴阳离子的同时测定

地质流体研究是地球科学领域的研究热点,矿物流体包裹体中成分是认识地质流体的关键。群体包裹体液相成分分析的传统方法大多采用单通道离子色谱分析阴离子,原子吸收光谱或电感耦合等离子体原子发射光谱分析阳离子,分析方法适用矿物种类少,单矿物需要量大（3g以上）。本文使用双通道离子色谱仪,经过大量条件实验,优化了样品爆裂、提取等前处理分析条件,确认了不同矿物可检测的离子,并采用富集方法将样品需要量由常规的3.00g减少到300mg,实现了石英、方解石、萤石、闪锌矿、石榴子石、磁铁矿和黄铁矿等多种矿物流体包裹体液相成分中Li⁺、Na⁺、K⁺、Mg²⁺、Ca²⁺、F^-、Cl^-、Br^-、NO₂^-、NO₃^-、SO₄^2-等阴阳离子的同时分析。所建立的离子色谱同时分析矿物流体包裹体液相微量成分分析方法简便、快速,成本低,用样量少,扩大了矿物种类的分析范围,为成矿流体研究提供了更加直接、有效的信息。     

Major ion composition and seasonal variation in the Lesser Himalayan lake: case of Begnas Lake of the Pokhara Valley, Nepal

The Begnas Lake in the Pokhara Valley is one of the threatened habitats in Nepal. The major ion chemistry explains the status of most of the inorganic nutrients and their possible sources. However, the earlier studies mostly cover limnological investigations, and phytoplankton and zooplankton diversity. Thus, the present study has been conducted to investigate the geochemical processes and to examine the seasonal variation of chemical composition within Begnas Lake. The results showed that SO ₄ ^2- , PO ₄ ^3- , and NO ₃ ^- increased compared with the previous values. The domination of Ca²⁺, Mg²⁺, and HCO ₃ ^- explains the influence of carbonate weathering on the major ion concentration. In general, pH and dissolved oxygen decreased with the depth of water-column, while electric conductivity, total dissolved solids, HCO ₃ ^- , Cl^-, H₄SiO₄, K⁺, Mg²⁺, Ca²⁺, Mn²⁺, and Fe increased. Among the cations, the predominance of Ca²⁺ and Mg²⁺ as characterized by high (>0.6) (Ca²⁺ + Mg²⁺)/(Tz⁺) and (>0.8) (Ca²⁺ + Mg²⁺)/(Na⁺ + K⁺) equivalent ratios, also suggests prevalence of carbonate weathering. The low value of (Na⁺ + K⁺)/Tz⁺ ratio shows deficiency of Na⁺ and K⁺, suggesting low contribution of cations via aluminosilicate weathering. The C-ratio suggests a proton source derived both from oxidation of sulfide and dissolution and dissociation of atmospheric CO₂ during different seasons. Though the major hydro-chemical parameters are within permissible limit, the increase in trophic state of the lake suggests that inherent biogeochemical processes make the limiting nutrients available, rendering eutrophic effect. Therefore, further comprehensive studies incorporating sediment–water interaction ought to be carried out to explain the ongoing phenomena and curb the eutrophication process in the lake.     

Geochemical Characterization and Controlling Factors of Chemical Composition of Spring Water in a Part of Eastern Himalaya

This paper focuses on the suitability of spring water for drinking and irrigation purposes in a part of eastern Himalaya, south Sikkim. There are many anthropogenic and geogenic factors contributing as a source of major cations and anions in the spring water. The spring water chemistry show a variation in EC, pH, TDS, Temperature, Na⁺, K⁺, Mg²⁺, Ca²⁺, Fe²⁺, Pb, Mn, Cu, HCO₃^-, Cl^-, PO₄^3-, NO₃^-, F^- and SO₄^2-. Mainly two types of water quality indexing has been used, one for suitability of spring water for drinking purposes and the other for irrigation purposes. For drinking purposes, Piper diagram used for determination of water type, water quality index (WQI) for quality monitoring and saturation index for mineral dissolution in water. % Na, RSC (Residual Sodium Carbon) and SAR (sodium absorption ratio) have been used for irrigation suitability. Piper diagram shows that CaHCO₃ type of water was dominant in the study area. The WQI depicted excellent category and SAR, percent sodium and RSC (Residual Sodium Carbon) depict excellent, good and permissible category for irrigation purposes. Principle component analysis (PCA) was used to determine the major influencing factor responsible for the variability in the parameters analysed of spring water.     

河北汤泉地热流体水文地球化学特征及其成因

提要：汤泉位于河北省遵化市西北部,为山前丘陵地貌,地热资源丰富。本文通过对该地区地热流体研究发现：Na⁺、Ca²⁺、K⁺、Mg²⁺与SO^2-₄、HCO^-₃、Cl^-、NO^-₃是该地区地下热水的主要成分,水化学类型主要为SO^2-₄-Na⁺型,属于未污染的天然弱碱性水;流体中F^-含量平均为9.36 mg/l,远高于国家地下水质量标准ⅴ级;可溶性SiO₂的含量可作为地热温标;地热流体总矿化度平均为782.33 mg/l,属于淡水;为中等腐蚀型水,不结碳酸钙垢,无CaSO₄?2H₂O垢和SiO₂垢生成的可能;地热流体属于含岩盐地层溶滤的陆相沉积水;根据氢氧稳定同位素可知,河北汤泉地热流体主要来源于大气降水。     

天山乌鲁木齐河源1号冰川融水径流水化学特征研究

2006年和2007年的整个消融期内,在天山乌鲁木齐河源1号冰川末端水文控制点逐日定时采集融水径流样品,对样品的主要可溶离子、pH、电导率EC、总溶解固体TDS和悬移质颗粒物SPM进行了分析. 结果表明：天山乌鲁木齐河源1号冰川融水径流离子类型为Ca²⁺-HCO₃^--SO₄^2-,呈弱碱性. 融水径流中TDS变化受日径流量调节显著,表现为消融初期和末期浓度较高,消融强烈时浓度较低;SPM以细颗粒物质为主,各粒度组分含量变化幅度较大,且质量浓度SSC年内变化与TDS呈相反的变化趋势. 融水径流中离子组成主要受岩石风化作用影响,离子摩尔比值和Piper图分析表明,控制冰川径流离子组成的主要过程是碳酸盐、黄铁矿和长石类矿物风化作用.     

Study of precipitation chemistry over an industrial city

The growing trend of industrialization has marked impact on the atmospheric chemistry around the globe. Such impacts are also predicted for developing countries like India. Acid precipitation due to secondary pollutants is one of them. The present investigation was conducted with an aim of studying the precipitation chemistry over Asansol city, India during the monsoon season. The rain water samples, collected on event basis during the period of June to September 2006, were analyzed for HCO₃ ^?, Cl^?, SO₄ ^2?, NO₃ ^?, NH₄ ⁺, K⁺, Na⁺, Mg²⁺, Ca²⁺ and pH using standard procedures. The study revealed that the precipitation was alkaline in nature with mean pH value of 6.08. Dominant anion in rain water samples was HCO₃ ^? (36 %), whereas Ca²⁺ was highest among the cations (53 %). The observed acidic events, based on pH value, were only 17 %, indicating the alkaline components effectively neutralize rain water over the area. This was also supported by the total alkaline to acid ion ration of 1.05. The ratio of (NO₃-^?+Cl^?) and SO₄ ^2? was >1, indicating that acidic properties were influenced by HNO₃ and HCl. In the ratio between (Ca²++NH₄ ⁺) and (NO₃ ^?+SO₄ ^2?), values >1 were obtained, indicating significant alkaline influence, which effectively prevented acid depositions in the area.     

Hydrogeochemical evaluation of groundwater quality and seasonal variation in East Bokaro coalfield region,Jharkhand

Groundwater samples collected from the East Bokaro coalfield of Jharkhand state, India during the dry and rainy seasons of the year 2012. Samples were analyzed for the assessment of groundwater quality in the study area. The results of the chemical analysis indicate that the pH values were found alkaline in nature during both the season. The major cations in groundwater was in the order of Na⁺>Ca²⁺>Mg²⁺>K⁺ during the dry season while Ca²⁺>Na⁺>Mg²⁺>K⁺ during the rainy season. The abundance of the major anions was of HCO₃^->SO₄^2->Cl^->NO₃^->F^- did not change on the seasonal basis. The average NO₃^-concentration was exceeded the desirable limit for drinking water as per Indian standard in the rainy season. Silicate weathering was inferred to be a dominant process, controlling the groundwater chemistry in both seasons, with lesser contributions by carbonate weathering and ion exchange. Leaching of salts from the unsaturated zone also has a major impact on groundwater quality during the rainy season. The water quality data indicate that groundwater is generally suitable for irrigation. However, higher salinity and residual sodium carbonate values at some sites may limit groundwater use and therefore an adequate drainage and water management plan for the study area is required.