Abstract 183 groundwater samples were collected from Birbhum district (a semi-arid region) of West Bengal, India to assess their irrigational suitability. Cations were found in the order of Ca2⁺>Mg2⁺>Na⁺>K⁺ whereas, anions were HCO3‾>Cl‾>SO42−. The average values of trace metals were recorded in the order as Total Fe>Zn2+>Cu2+>Ni2+>Pb2+>Co2+>Cd2+. Water quality for irrigation purpose was assessed through a newly developed Integrated Irrigation Water Quality index (IIWQI) and other existing indices such as sodium adsorption ratio (SAR), residual sodium carbonate (RSC), sodium percentage (Na%), salinity and Wilcox diagram, magnesium hazard (MH), permeability index (PI) and Kelly index (KI), which indicated that groundwater were suitable for irrigation purpose. The sensitivity and uncertainty analysis by Monte Carlo Simulation indicated that Cd2+, TDS, Cl‾ and HCO3‾ were the most influential parameter, which controlled the water chemistry with 83.99% probability of water quality certainty in the range of 0.4–0.6. The GIS distribution maps with Empirical Bayesian Kriging (EBK) modelling through predicted vs measured and semivariograms plots, described the accuracy and robustness of various water quality models. Major hydrochemical facies were normal earth alkaline of Ca2⁺-Mg2⁺-HCO3‾ type and Ca2⁺-Mg2⁺-SO42−-Cl‾ type. Groundwater chemistry of the study area was mainly influenced by the local geological setting and rock weathering. Reverse ion exchange, silicate weathering and rock weathering such as dissolution of aragonite, calcite, dolomite, fluorite, halite governed the hydrochemistry. The study demonstrated the application potential of IIWQI and EBK in groundwater quality studies with potential advantages. The outcome of the study will provide a new insight for effective management of groundwater for irrigation purposes.

中文翻译：

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综合地下水质量指数的空间和敏感性分析对灌溉适宜性调查

摘要 从印度西孟加拉邦Birbhum 区（半干旱地区）采集了183 个地下水样本，以评估其灌溉适宜性。发现阳离子的顺序为 Ca2⁺>Mg2⁺>Na⁺>K⁺，而阴离子为 HCO3‾>Cl‾>SO42−。痕量金属的平均值按总Fe>Zn2+>Cu2+>Ni2+>Pb2+>Co2+>Cd2+的顺序记录。通过新开发的综合灌溉水质指数 (IIWQI) 和其他现有指标，如钠吸附率 (SAR)、残留碳酸钠 (RSC)、钠百分比 (Na%)、盐度和威尔科克斯图，评估灌溉用水的水质、镁危害（MH）、渗透指数（PI）和凯利指数（KI），表明地下水适合灌溉。蒙特卡罗模拟的敏感性和不确定性分析表明，Cd2+、TDS、Cl‾ 和 HCO3‾ 是最有影响的参数，其控制水化学的概率为 83.99%，在 0.4-0.6 范围内。通过预测与测量和半变异函数图使用经验贝叶斯克里金 (EBK) 建模的 GIS 分布图描述了各种水质模型的准确性和稳健性。主要水化学相为Ca2⁺-Mg2⁺-HCO3‾型和Ca2⁺-Mg2⁺-SO42--Cl‾型的正碱土。研究区地下水化学主要受当地地质环境和岩石风化作用的影响。逆离子交换、硅酸盐风化和岩石风化如文石、方解石、白云石、萤石、岩盐的溶解控制了水化学。该研究证明了 IIWQI 和 EBK 在地下水质量研究中的应用潜力，具有潜在优势。该研究的结果将为有效管理用于灌溉目的的地下水提供新的见解。