Climate change earth is our love… As water is universal solvent, the cause of it’s contamination vary greatly at different locations. You have mentioned few rightly such as the composition of host rock, the contamination from surface including both artificial and natural, saline intrusion, the water budget (in/out of water in system) etc.

موسمیاتی تبدیلی اور اور ھماری سوچ کیا ھم آنے مصیبت کا سامنا کر پائیں گے

It needs the research to figure out the causes of poor water quality at different location Climate change is biggest threat to life and livelihood. Not only the developing countries but the developed countries are reluctant to realize  adapt accordingly. So the alarm bell is ringing but we are failing ourselves gravelly. It is mainly, most probably due to over usage of groundwater as compared to its recharge. The corresponding channel or stream of your particular area is major reason means when it is flowing with good budget of water the adjacent water table is recharged with fresh water and wise versa

I mean usage of those low profile or unauthorized ones having inappropriate composition which may damage soil as well as contaminate groundwater

Conclusion to Climate change earth is our love…

 Our bigger adversary is the economic interests and unimaginable self comfort. From country to individual no body wants to compromise on economic well being and comfort level at the cost of climate.

Mark my words we are heading towards worst times ahead.