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A coal-bed methane drilling rig in Wyoming. Water containing compounds such as sodium bicarbonate is often extracted from the ground as companies produce oil and gas.Jordan Edgcomb/The Associated Press

Companies discharging water produced from certain types of natural gas wells may be harming – and even killing – aquatic wildlife in the United States, leaving scientists warning the same may hold true for other types of oil and gas operations.

The U.S. Geological Survey, working in concert with other agencies including the U.S. Environmental Protection agency, released results of an eight-year study Thursday, concluding salty water from coal-bed natural gas production that ends up in streams and rivers is adversely affecting fish and other organisms.

While the scientists did not provide any regulatory recommendations, the study's results could affect energy laws around the globe should the United States crack down on water rules. Controversy around hydraulic fracturing, which is an important and prolific oil and gas extraction method, already has green groups and landowners upset, and concerns raised in the USGS report will further stir emotions.

Water containing compounds such as sodium bicarbonate is often extracted from the ground as companies produce oil and gas. Select jurisdictions allow energy companies to dispose of this so-called produced water by discharging it directly into watersheds, treating it and then sending it to watersheds, putting it in injection wells, or by other methods.

USGS scientists studied the effects of discharging produced water into the Tongue and Powder river basins in Montana and Wyoming. They took water samples from small tributaries that feed these rivers and then mimicked the chemical composition of those samples in the lab.

Aquatic life placed in tanks with the water "had difficulty surviving" depending on the salt concentration, the USGS said.

"Though this investigation focuses on the Tongue and Powder river basins, the information is applicable to other watersheds where sodium bicarbonate is a principal component of product water either from [coal-bed natural gas] or from traditional or unconventional oil and gas development," the agency said in its report.

Even though these tributaries involved in the experiments feed the Tongue and Powder rivers, the scientists ruled wildlife in these rivers were not threatened because the larger waterways sufficiently diluted the produced water, David Harper, a fishery biologist with the USGS said.

Given that the USGS indicated the problem could extend beyond coal-bed natural gas wells, the effect on the industry could be widespread. But some jurisdictions have already taken action.

For example, Encana Corp., North America's second-largest natural gas company, does not operate in any areas where energy companies are permitted to discharge produced water – even after being treated – to the surface, said Jay Averill, a spokesperson for the Calgary-based company.

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