Groundwater quality assessment using multivariate statistical technique and hydro-chemical facies in Birbhum District, West Bengal, India

The assessment of quality of groundwater is an important issue in the present era of population growth, massive agricultural development, industrialization and urbanization. As the demand of groundwater increases, the quality becomes deteriorated. In this background, the study of groundwater quality in Birbhum District is very much important as this area has been characterized by diversified rock formations. For the analysis purpose, 14 parameters regarding the hydro-chemical data of groundwater, viz. PH, electrical conductivity, total hardness, calcium, magnesium, sodium, potassium, bicarbonate, chloride, sulfate, fluoride, silicon dioxide, phosphate and iron, were selected. The present study has been carried out using multivariate statistical method, viz. principle component analysis (PCA) and cluster analysis. In addition, different hydro-chemical facies in terms of hydro-chemical diagrams have been used to show the present status of groundwater quality in the concerned area. The result of PCA, a multivariate statistical technique, reveals that it extracts five major factors accounting for 80% of the total variance. Fluoride has been extracted as first factor. It is because the western part of the district has been characterized by highly fluoride contaminated area where basaltic terrain is present. The study also shows concentration of cation and anion that are present in the order of Na+ > Ca2+ > Mg2+ > K+ = Cl− > HCO3− > SO42−. Two clusters have been prepared: one for sample villages and another for chemical components. Sample village-wise cluster reveals that Baidyanath, Muluk, Khayrasole, Md Bazaar, Patel Nagar, etc. bear same chemical characteristics, while chemical component cluster shows the homogeneous grouping among PH, PO4, Sio2, Fe. Diagrammatic presentation of chemical parameters is also an important aspect in this study. Here application of Wilcox diagram basically depicts the nature of water for the suitability of irrigation. It shows that about 50% samples out of total sample have been characterized by excellent to good, the rest 25% samples present in good to permissible category, 20% are under the category of permissible to doubtful and 5% belong to the category of doubtful to unsuitable, while Gibbs mechanism displays 68% samples belonging to the category of rock dominance and the rest 32% in precipitation dominance category. This kind of study obviously demand an important space as groundwater quality is directly related to human health. So, for the sustainable development of human health, this type of study opens a new dimension for the betterment of the society and the concerned region.