Opponents of hydraulic fracturing point to environmental risks , including contamination of ground water , depletion of fresh water , contamination of the air , noise pollution , the migration of gases and hydraulic fracturing chemicals to the surface , surface contamination from spills and flow-back , and the possible health effects of these .
Opponents point to potential environmental effects , such as contamination of ground water , risks to air quality , the migration of gases and hydraulic fracturing chemicals to the surface , surface contamination from spills and flowback and the health effects of these .