A contaminant fate transport modelling approach to assess the impact of tannery wastewater on groundwater vulnerability in a hard rock terrain

Abstract

The upper Kodaganar basin composed of hard rock terrain is located in Dindigul district South India It has a specific significance and requires great attention because groundwater is the only major source for domestic consumption and irrigation that gets contaminated The groundwater in the basin is alkaline with TDS concentrations that range from 249 19810 mgL in the post monsoon and 283 20120 mgL in the pre monsoon season The concentration of pre monsoon groundwater is higher than that of postmonsoon The chloride concentration ranges from 25 10800 mgL and sulfate concentration ranges from 2 6584 mg L Wells with extreme high concentration are found in the central part of the basin The groundwater in this region is contaminated due to the tannery wastewater in the Sengulam lake The groundwater in about 70 of the wells is unsuitable for drinking The groundwater in about 57 of the wells does not satisfy the irrigation standards and is unsuitable for irrigation With the aid of correlation matrix it is found that electrical conductivity has a good correlation with Ca2 092 Mg2 075 Na 085 K 085 and SO42 089 The scree plot has helped in identifying the Eigen values used to select the appropriate principal components PC1 7 26 and PC2 2 24 that accounted for 73 04 variance in the data are selected for the analysis The components of the parameters and the wells are plotted in a biplot to isolate the contaminated samples newline