Natural gas extraction is associated with several known teratogens. A study published in the journal Environmental Health Perspectives on January 28th by researchers from the Colorado School of Public Health and the Department of Epidemiology of Brown University, USA, finds that for those babies born of mothers living with greater density of natural gas wells within a ten mile radius of their residence, there was an increase in congenital heart defects, and a possible link with increase in neural tube defects. 1
This is significant for current debates about the future of methods to extract shale gas inland in the UK, including the use of hydraulic fracturing (or fracking as it is more commonly known). Fracking involves a method for extracting natural gas from impermeable rocks deep within the earth by deep drilling, firstly vertically, then horizontally, and the injection of a mixture of water, sand and chemicals at high pressure into the wells to cause fissures into the rock (hydraulic fracturing) through which natural gas can escape up to the surface. The aim is that the fracturing will take place beneath the water table so that the water supply is not polluted by the mix of chemicals, methane gas and rock that are produced. The water sand and chemical mix that had been injected into the well is then partially recovered (it is never possible to recover all of it) and this waste fracking fluids, complete with fragments of rock from deep in the earth, must be disposed of. The technology requires that large numbers of wells are drilled in order to extract the gas, and requires the transportation of millions of gallons of water and chemicals to the drill, as well as some method of disposal of the waste. (The precise method of disposal for proposed UK fracking is not yet clear: in the States, evaporation pits are often used, but these are, for good reason, illegal in the EU.)
The debate about the safety of fracking is complex and it is important to tease apart some of the many points that may possibly muddy the debate. One of the difficulties is collating and assessing evidence of harm; another difficulty is in assessing how we extrapolate data of risks and benefits from one situation to another, when there may be variations in geography, geology, techniques used, chemicals used, regulations, and law. There is much to consider, so here I just discuss a couple of points to indicate how complex the debate is. One main lesson should be that simplistic assurances of lack of risk from fracking should be listened to with caution.
Read More »Difficulties in assessing the risks of hydraulic fracturing and shale gas extraction: new study shows correlation between birth defects and proximity to gas wells in Colorado.