Hierarchical cluster analysis (HCA)
A Q-mode HCA was performed in the study area to understand the chemical
composition of groundwater. It is the most efficient tool for data
classification and useful graphical methods to identifying the source of
contamination in groundwater (MarĂn Celestino et al., 2018). HCA
analysis was carried out in the study area based on the water quality
parameters and sample stations. Also, the Wards linkage method with a
square Euclidean distance classification method for comparison
measurement is used to produces the most distinctive groups in the
dendrogram (Prajapati et al., 2020). The result of HCA in the study
area, cluster 1, comprises CO32-,
F-, pH, K+, Na+,
NO3-, Mg2+,
SO42-, Ca2+,
HCO3-, and Cl- are
jointly associated with together. Cluster 2 shows that TH associated
with cluster 1, and it indicates geogenic source, weathering of calcite
and dolomite rocks, and anthropogenic activities. Cluster 3 represents
the EC and TDS associated with clusters 1 and 2 (Fig.17a). It shows that
the reverse ion exchange process is highly influencing the nature of
groundwater in the study area (Table.9a). In addition, HCA was performed
based on the sample location and shown in fig. 16b. It shows that, three
different types of groups are group1 comprises sample locations
1,3,17,18 and 20, group 2 represents 4,5,7,10,14,22,24 and 27 and group
3 comprises 2,6,8,9,11,12,13,15, 16,19,21,23,25,26,28,29 and 30
(Table.9b). A partial number of sample locations are having the same
characteristic of groundwater and less contamination (Fig.17b). The
results of the HCA variable and sample locations are reveals that
geogenic and reverse ion exchange and anthropogenic activities such as
waste disposal, sewage intrusion and excess utilization of synthetic
fertilizers are high influencing the nature of groundwater.