On the subject of hydraulic fracturing of shale gas formations (fracking if you must), one of the main objections seems to be the possibility of groundwater contamination from the chemicals involved in the water injection process. Whilst the proportion of chemical additive to water is very low, there are large amounts of water involved – many thousands of tonnes meaning a few hundred litres of chemicals albeit some quite innocuous ones that are often found in foodstuffs such as guar gum, salt and a few others.

With that slight aside out of the way, having read a little on the subject, the following quote came to mind this morning when reading a BBC article (quote from US DOE report – opens pdf) :

A typical fracture treatment will use very low concentrations of between 3 and 12 additive chemicals depending on the characteristics of the water and the shale formation being fractured.

The piece in the BBC article which prompted that thought? Well, I think you will agree that this has a somewhat different slant on it :

Fracking – short for “hydraulic fracturing” – involves drilling deep under ground and releasing a high-pressure mix of water, sand and hundreds of chemicals to crack rocks and release gas stored inside.

Interestingly, I grabbed that specific quote this morning but the article has now been amended to read :

Fracking – short for “hydraulic fracturing” – involves drilling deep underground and releasing a high-pressure mix of water, sand and chemicals to crack rocks and release gas stored inside.

I wonder where the “hundreds” disappeared to? It is still available here for example.

As for it’s origin, I suspect some BBC research wonk did a bit of googling and blundered over the list at  this wiki link which gives the 750 or so recognised additives used in various operations.