Only a Matter of Time
by D. Barrie Clarke, Adjunct, Department of Earth Sciences Dalhousie University

1. Most people, including politicians and resource-sector executives, consider issues on time-scales of hours to years, but earth scientists routinely deal with natural processes that occur over decades to millions of years. The issue, and consequences, of hydraulic fracturing properly belong in the latter category.

2. A time-bomb is a device that is set to cause destruction to people or property at some time in the future, after the agent that set the device is remote, in space and/or time, from its destructive effects. Conventional time-bombs have fuses that are hours to days in length, but environmental time-bombs have “fuses” that are decades to millennia in length.

3. Arsenic poisoning of the groundwater in Waverley, NS, in the 1970s, for example, was the unanticipated legacy of the gold-mining time-bomb set in the 1870s. Its arsenic- and mercury-contaminated mine tailings still constitute present-day environmental problems and future clean-up costs (Parsons et al. 2012). Those human-health and remediation costs are borne by people today, not the gold-mining companies of yesteryear. Fool us once, resource-extraction industry – shame on you.

4. Naturally occurring, deep-seated, low-viscosity materials (e.g., gas, petroleum, brine) always migrate upwards to lower pressure. The toxic cocktail of man-made fracking fluids will behave in exactly the same way. This migration of fluids is subject only to D’Arcy’s Law, which states that the fluid flow rate is directly proportional to the permeability (k), the hydraulic pressure gradient (dh/dL), and the cross-sectional area of the flow (A), and not to unscientific claims of safety by the petroleum industry.

5. Fracking deliberately destroys the impermeability (k=0) of rocks containing oil and gas; once their permeability is greater than zero (k>0), all fluids, both natural and synthetic, begin their upward migration, even if the well casing is properly sealed. In the absence of any stratigraphically higher impermeable horizons, those fluids will have hydraulic connectivity with the surface and must eventually reach the groundwater system (Vengosh et al. 2013).

6. “The complexities of contaminant transport from hydraulically fractured shale to near-surface aquifers render estimates uncertain, but a range of interpretive simulations suggest that transport times could be decreased from geologic time scales to as few as tens of years. Preferential flow through natural fractures [and] fracking-induced fractures could further decrease the travel times…” (Myers, 2012).

7. For balance, Flewelling and Sharma (2014) offer the expected, contrary, dismissive, industry-funded view.

8. Fluid migration times are longer than the history of fracking in relatively shallow horizontal wells, but it’s only a matter of time until the fracking fluids reach the groundwater system. What goes down, must come up. The petroleum industry already knows this. How else to explain the Bush-Cheney “Halliburton exemption” from the anti-pollution provisions of the Safe Drinking Water Act in the USA?

9. Poisoning of the groundwater again in Nova Scotia could, therefore, become the undesirable 2114 legacy of a fracking time-bomb set in 2014, but by that time the frackers will be long gone with their environmentally untaxed profits, and future generations will be left to pay in terms of their health and their taxes again. Fool us twice, resource-extraction industry – shame on us.

10. Humans can, and eventually must, live without fossil fuels, but never without water. So, where will the people of North Dakota, Pennsylvania, Texas, and New Brunswick migrate when their groundwater becomes irretrievably contaminated by fracking fluids, except to pristine places such as Nova Scotia, which had the prudence and good sense to reject hydraulic fracturing in 2014?

D. Barrie Clarke, Adjunct, Department of Earth Sciences Dalhousie University, Halifax, NS B3H 4R2

Much of the objective scientific information that the Hydraulic Fracturing Panel needs to consider is available on-line in places such as the Council of Canadian Academies panel website:
and (in English) from Germany’s premier geological research institute (GeoForschungsZentrum-Potsdam): http:// /
Also, because the shale gas issue should not be considered in isolation, I highly recommend Energy for Future Presidents by Richard A. Muller (W. W. Norton & Company, 2012, ISBN 978-0-393-34510-0) as a comprehensive and highly readable account of all current and future energy options.

Flewelling, S. A. and Sharma, M., 2014. Constraints on upward migration of hydraulic fracturing fluid and brine. Groundwater 52, 9-19. doi: 10.1111/gwat.12095
Myers, T. 2012. Potential contaminant pathways from hydraulically fractured shale to aquifers. Groundwater 50, 872-882. doi: 10.1111/j.1745-6584.2012.00933
Parsons, M.B., LeBlanc, K.W.G., Hall, G.E.M., Sangster, A.L., Vaive, J.E., and Pelchat, P., 2012. Environmental geochemistry of tailings, sediments and surface waters collected from 14 historical gold mining districts in Nova Scotia; Geological Survey of Canada, Open File 7150. doi:10.4095/291923
Vengosh, A., Warner, N., Jackson, R., and Darrah, T., 2013. The effects of shale gas exploration and hydraulic fracturing on the quality of water resources in the United States. Procedia Earth and Planetary Science 7, 863-866. doi: 10.1016/j.proeps.2013.03.213

Acknowledgements: I wish to thank G.B., J.C., J.D., A.F., A.M., D.P., M.P., and J.W. for their constructive comments on this document.
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