Water quality in Pennsylvania hasn't been affected by hydraulic fracturing in the state, a report from state's conservation department said.

The Pennsylvania Department of Conservation and Natural Resources published a 265-page document on the ecological and environmental impacts of hydraulic fracturing in the state.

Part of the lucrative Marcellus shale natural gas reserve basin lies under Pennsylvania. The basin is one of the top natural gas producers in the country.

The DCNR's report said water quality is often cited as the area were most people have expressed concern about hydraulic fracturing, a drilling practice known also as fracking.

"Although incidents have occurred, the monitoring data show that water quality has not been affected due to this activity," the report said.

Some of the chemicals used in the practice are seen by fracking opponents as a threat to groundwater supplies.

The DCNR said invasive plant species and pests have been able to take advantage of the ecological and environmental disturbances caused by drilling. This "clearly shows" energy companies need to carefully manage their activity to control the spread of invasive species.

The report added more than 1,400 acres of forest were exploited for natural gas development through 2012, though that number is lower than it could've been because of management decisions.