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A preliminary hydrogeochemical investigation of groundwater quality for spatially distributed habitations of Chandel district of Manipur was carried out with an objective to assess the suitability of groundwater for different anthropogenic uses. Altogether, eighteen (18) physico-chemical parameters including in situ parameters and major ions were analysed for classification and hydrogeochemical characterisation of groundwater resources of the study area. Some of the anions such as Cl− and SO42− were found in exceeding concentrations. Similarly, 23.1% samples exceed fluoride (F−) concentration beyond the permissible limit of 1.5 mg/l. The water quality index of the groundwater samples of the habitations was found to be influenced by the elevated concentrations of water quality parameters such as F−, EC, TDS, salinity, Cl− and SO42−. The geochemical analysis reveals that the majority of geochemical facies of the groundwater samples are dominated by Na+–Ca2+–Mg2+–Cl−–HCO3−–SO42− type of water resulting from rock-weathering geochemical process. Bivariate and multivariate analysis indicates the influences of hydrogeochemical interactions in the aquifer on the overall water quality. The irrigational water quality indices demonstrate that the water qualities of most of the sources are within the acceptable range except for few samples with high salinity and alkali hazards.

Hydrogeochemical evaluation and assessment of groundwater quality was carried for selected areas of Bishnupur district of Manipur to ensure its suitability for drinking and irrigational uses. Twenty physico-chemical parameters of groundwater samples from thirty-one spatially distributed areas were assesed including major geogenic contaminants such as Fe3+, As3+ and F- to ensure public health safety. In-situ parameters such as temperature, pH, EC, DO, salinity, ORP, TDS were determined using field sensors and other parameters were analysed using standards methods. The suitability of groundwater for potable use was assessed using drinking water quality index based on World Health Organisation standards. Groundwater quality indices exhibit very poor results due to presence of high dissolved solids, higher values of EC, excessive hardness and presence of geogenic contaminants in the groundwater samples. Irrigational water quality of groundwater resources showed satisfactory results according to the various irrigational water quality parameters and indices. Geochemical evaluation showed most of the groundwater sources are dominated by Ca-Mg-Na-HCO3−-Cl− type of water mainly originated from silicate and carbonate rock-weathering or dissolutions processes.

Hydrogeochemical and multivariate assessment of groundwater samples of the Churachandpur sub-division of the state of Manipur was carried out to study its suitability for potable and irrigational uses. The study extensively discusses the underlying hydro-geochemistry using multivariate geostatistical tools for physicochemical parameters of 35 spatially distributed groundwater samples during pre- and post-monsoon seasons. In situ parameters (pH, TDS, DO, EC, salinity, ORP) were assessed in field conditions, and it was found that few samples exceed concentration than the prescribed standards. Both positive and negative ORP values and low DO levels of the samples indicate oxidizing and reducing aquifers due to recent unstable geologic formations. Although the concentration of Cl−, SO42−, and NO3− is well within desirable levels, the concentration of F− and As3+ of a few samples exceeds the prescribed standard. The water quality index of the groundwater samples signifies that more than 50% of samples are unsuitable for potable uses for both seasons. The geochemical analysis indicates that most of the water is Ca–Mg–Cl–HCO3 type followed by Mg–Ca–Cl–HCO3 types in both the seasons and dominated by the rock-weathering geochemical process. Multivariate analysis and geostatistical mapping highlight the spatial variability of water quality parameters and possibilities of the occurrence of geogenic contaminants in the aquifers of the study area.

A comprehensive assessment was conducted to evaluate the accumulation of selected heavy metals and nutrients in 10 dominant macrophyte species growing in the Loktak Lake, a Ramsar site, and to assess the potential health risks associated with the consumption of the edible plants. The concentrations of nutrients such as total phosphorus (TP), total nitrogen (TN), potassium (K), calcium (Ca), magnesium (Mg), and heavy metals such as copper (Cu), manganese (Mn), zinc (Zn), and iron (Fe) were measured, and found to be present in the order of plant > sediment > water. The bioaccumulation factors (BAFs) revealed high efficiency of most plants to accumulate heavy metals and nutrients in their tissues from the lake water and sediments, indicating their potential to be used as phytoremediators. Translocation factors (TFs) were also estimated to determine the efficiency of the plants to translocate elements from root to shoot. Colocasia esculenta and Polygonum perfoliatum were found to exhibit the highest BAF and TF values for most of the parameters. Target hazard quotients (THQs) revealed potential health risk associated with one or more heavy metals in the plants, except for Zn whose THQ values were below the level of concern in all the edible plant species. The hazard index (HI) signifying potential non-carcinogenic health risk from the combined effects of all the heavy metals was found to be highest for Polygonum perfoliatum, indicating a potentially higher risk to health if this edible macrophyte is regularly consumed in higher quantities and may pose long-term health effects to the exposed population.