Fracking not to blame for tainted water

Fracking is the controversial technique using high pressured water to extractnatural gasses from deep below the earth's surface. Many have voiced worries that fracking can contaminate local water supplies with gasses like methane. A recent study has suggested this might not be down to fracking itself, but to poorly built wells at the sites. Science writer Mark Peplow told Chris Smith the details of the study...

Mark - The point is, this means that the fracking process isn't to blame for any methane contamination. It's the result of poor workmanship at the borehole. And then that borehole is lined with steel and concrete to stop the gas escaping as it rises through the pipe. The key thing is, that suggests that it should be possible to eliminate the leakage by simply doing a proper job. What it does highlight is that you need really strong regulations to insure that the wells are constructed properly.

Chris - How did they do this sort of methane post-mortem?

Mark - It's absolutely fantastic. They used a really clever bit of chemical analysis to work out where the methane in their samples have come from. So, the first step is to look at the ratio with methane and ethane in the water to see if it matches the gas in the shale.

Chris - So, ethane and methane are both found underground, are they?

Mark - Yes, they are. Natural gas that comes through your cooker is methane, but in gas deposits, you tend to get some heavier hydrocarbons as well which are still gases, such as ethane. What you do is you just see if it matches up. But the trouble is, those ratios can be altered by microbes or by chemical reactions with oxygen, so you need another way of looking at this. So, they looked at the ratios of gases like helium and neon, and argon. Now, these are noble gases - so-called because they're very unreactive, so they're not altered by biological chemical processes. Each shale region has a characteristic makeup with all these gases, its chemical fingerprint. Crucially, that fingerprint does change in a predictable way at various stages of the process as the gas is dissolved in fracking fluid, as it moves through the borehole, and as it gets into aquifers. So, you look at these fingerprints and you can effectively map out where the gas just flowed before it got into the water wells. And they looked at 130 wells in Pennsylvania and Texas and found 8 clusters of wells near shale gas sites where there had been leakage through the borehole casing, but not directly from the fracked shale beneath.

Chris - Good grief, so you can actually tell at what point in the underground journey the gas is taking it has exited from the fracking operation and actually got into the groundwater supply.

Mark - Yeah, that's right.

克里斯,很让人印象深刻。显然now fingers that particularly bit of engineering so, a.) is there a blame attached to this now, are we looking at legal cases? And b.) can this be remedied or rectified, now the fracking operations in those places are in situ?

Mark - There is a legal case ongoing in Texas that this might have some impact on. in terms of rectifying it, yes, they can be rectified. But obviously, what needs to be done is to have the proper regulations in place to make sure that this is done properly in the first instance.

Chris - Would the regulations in place here in Britain have stopped that sort of poor infrastructure being used which is causing this problem in America?

Mark - I think that's impossible to know. Certainly, advocates for fracking, say, that "of course, nothing like that would happen over here". It's very difficult to know because things are moving more slowly over here than they did do in the US, and because there's such a focus of public attention on the issue, I suspect that any regulator would be down on dodgy operators like a ton of bricks. So in a sense, the public furore about it, may actually help to insure that if fracking does move forward, regulators keep a very careful eye on it to make sure that these wells are created in the right way.

Chris - And worst case scenario, say it does happen. The presence of methane and a bit of ethane in people's water, does it pose a threat to people?

Mark - Probably not, but there really isn't enough literature yet out there to know for sure. Of course, it's something that naturally concerns people. When you're losing methane out of your well, it's actually a major problem if it's escaping into the atmosphere. There's been a lot of talk actually about how shale gas is a good thing for tackling climate change because it burns cleaner than coal, it doesn't produce as much carbon dioxide emissions. But if you're allowing methane to leak from your well, methane is a much, much more powerful greenhouse gas than carbon dioxide. So, if you've got a leaky shale gas operation, that could actually be worse in terms of climate change than burning coal.