Extraction using hydraulic fracturing - fracking - has made North America the world's largest producer of oil and gas, while US CO2 emissions from energy have dropped back to early 1990s levels and the most offensive producer, coal, has been pushed back to 1980s levels. Despite those benefits, there have endless protests from environmentalists that fracking is worse for pollution. 

Does drilling for natural gas really cause pollution levels to skyrocket, the way activists claim? 

A team of geochemistry researchers affiliated with Concordia University, l'Université du Québec à Montréal, l'Institut national de la recherche scientifique, and the GEOTOP research group created a study to examine the natural quality of groundwater prior to fracking and they say their report provides a benchmark for naturally occurring levels of pollution.

They did this by establishing the concentrations of methane, ethane, propane, helium and radon found in the groundwater in a location where fracking has yet to occur — the low-lying areas surrounding the St. Lawrence River, between Montréal and Québec.

The challenges

Yves Gélinas, study co-author and professor in Concordia University's Department of Chemistry explains: "In several cases in the US where very high concentrations of methane were found in the vicinity of fracking sites, energy companies could not be held legally responsible for the contamination simply because there was no record of pre-exploitation gas levels in the groundwater. This study is the first to document natural gas levels, plus their sources, so that those levels can be compared to those at fracking sites."

That means that if the government allows the exploitation of natural shale gas resources at some point in the near future, scientists will be able to link any eventual contamination to mining activities.

The research

For this study, 130 residential and municipal wells were sampled in a region covering approximately 14,000km2 between Montreal, Leclercville and Trois-Rivières, as well as the foothills of the northern Appalachians.

Out of these wells, 14% per cent exhibit concentrations of methane greater than seven milligrams per litre — the acceptable threshold of methane in groundwater specified by the Government of Quebec. In the majority of the wells, the methane occurs naturally; that is, the gas is a by-product of bacteria emitted by surface sediments.

The most highly elevated concentrations of helium, which is an inert gas often observed in association with methane, were seen in the low-lying areas surrounding the St. Lawrence Seaway. These resulted from a particular geological formation in which important concentrations of naturally occurring methane are also observed.

No concentration of radon — a harmful gas that is both colorless and odourless — exceeded the level of permissible radioactivity established by Health Canada (2,000 becquerels per litre (Bq/L). However, in 4.6 per centof the wells, concentrations exceeded the levels recommended by the World Health Organization (100 Bq/L).

Gélinas cautions that, "radon is easily dispersed into the atmosphere and, consequently, there is an increased risk of breathing it in in poorly ventilated locations."

That's important to note because fracking has been linked by some to an increase in radon — which, in turn, has been linked to greater instances of cancer. Says Gélinas, "Now that we have established the normal levels of harmful chemicals like radon that naturally occur within a given area, we can carefully monitor whether these levels increase when big energy companies come in to mine for shale gas — and then hold those companies accountable if we do see pollution levels go up, as is widely believed."