Solid wastes being discarded in open dumping grounds or used as land fill in low-lying areas is causing soil run-off and groundwater pollution. The Pollution Control Board has conveyed this to the GHMC on various occasions, but to no avail. Water analyses around these sites have detected heavy elements, high Biological Oxygen Demand and Chemical Oxygen Demand, high hardness and alkalinity. Posing a potential threat to public health, the water has been deemed unfit for domestic use and consumption, the PCB said.