In Jaipur and its agglomerate we have studied different parameters like TDS,pH ,TH,Fluoride , Nitrate,Potassium , Sodium Electrical Conductivity and more.
How Toxicity appears to human being can be correlated.
Kindly prepare the distributions of those parameters TDS, pH ,TH, Fluoride , Nitrate, Potassium , Sodium, Electrical Conductivity by using GIS software. Classify those distributions based on the concentration (here you have to follow BIS or WHO standard).
Chemical distribution of water in the study area you can refer follow the paper;
Anbazhagan, S., Das, M.K., and Balamurugan, G., (2006). Hydrogeochemical Studies in Precambrian Hard Rock Aquifer System, Hosur. Indian Journal of Geochemistry. 21(2), pp. 519- 535.
Related to the toxicity appears to human you have to conduct the field survey. however, if you are going to to do some sample collection (health issues, skin diseases, other issues) kindly follow the norms.