SULPHUR AND HYDROGEN SULPHIDE
Tar sands bitumen contains huge amounts of sulphur. The sulphur must be removed before the bitumen can eventually become refined oil, but there is a glut on the world market and nowhere to send it. Already the mounds of raw sulphur extracted from tar sands bitumen are larger than the pyramids of Egypt and there’s more of it produced every day.
One “solution” is to convert the sulphur to hydrogen sulphide (H2S) and inject it underground into old oil wells, a process referred to as acid gas disposal. Hydrogen sulphide is extremely toxic. One breath over 1000 ppm can kill instantly while lower concentrations can cause permanent health damage. Oil wells will weaken over time and allow the stored H2S to leak, with deadly effect. Zama Lake, Alberta is a disposal site with sulphur accumulations much smaller than the tar sands; a study found that if a leak occurred there, an area 600 kms in radius could be unlivable for over 1,000 years because of poisoned air and water. That’s equivalent to an area of land around Winnipeg reaching from Regina in the west, all the way east to Lake Nipigon, north to The Pas and south to Sioux Falls, South Dakota.
As the mountains of sulphur grow larger, another “solution” to the problem is to leave sulphur in the bitumen when it is mixed with the diluent for transport to refineries, so that sulphur disposal becomes someone else’s problem. Many scientists consider this poses an additional danger, because the relatively large amount of sulphur in the dilbit can form hydrogen sulphide inside the pipeline. Thermal decomposition (a chemical decomposition caused by heat) and microbes in the pipeline act on sulphur to form H2S. This increases the concentration of H2S as the dilbit moves down the line.There’s no data in the Energy East submission to indicate the maximum temperature of dilbit in the line, however the five natural gas lines parallel to the dilbit line have been reported to reach 50 C in the summer. The dilbit line would be even hotter due to the higher viscosity.
In some cases, H2S is present at point of entry in the tar sands . In Cold Lake, for instance, the hydrogen sulphide content of dilbit is reported to be 300 ppm. (Interestingly, Enbridge, in the United States, has put worker safety policies in place that ban a higher than 5 ppm H2S content in the oil transported through their pipelines.)
Sulphur and hydrogen sulphide are right there in the pipelines and trains carrying dilbit across farmers’ fields, aquifers, rivers and through our communities. Where there’s a pipeline leak, there will be hydrogen sulphide released; and where there is hydrogen sulphide there is significant risk to life and health for people, animals, air and water.
There are many economic and environmental reasons to say NO to the pipeline. Sources and more information can be found in the recently released report, “Potential Impacts of the Energy East Pipeline On Winnipeg.”
Contributor: Mary Robinson – Council of Canadians Winnipeg Chapter Chair