Principal component analysis Cluster analysis 32 Heavy metals 17 Water quality 12 Factor analysis 10 Groundwater 9 Water quality index 9 more ... Heavy metal 6 Metals 5 Trace metals 5 Arsenic 4 Discriminant analysis 4 Geoaccumulation index 4 Hierarchical cluster analysis 4 Physicochemical parameters 4 Pollution load index 4 Polycyclic aromatic hydrocarbons (PAHs) 4 Sediment 4 Sequential extraction 4 Soil 4 Support vector machine 4 Trace elements 4 Carcinogenic risk 3 Enrichment factor 3 Hazard quotient 3 India 3 Multivariate analysis 3 Multivariate statistics 3 Pakistan 3 Soil pollution 3 less ...