As the effects of climate change are more keenly felt and the demand for renewable energy increases, the fossil fuel industry is estimated to have a lifespan measured in just a few decades. The world’s food supply needs to last much longer. Ensuring our food security into the distant future will require an abundance of fertile, productive, uncontaminated cropping and grazing land.
Soil can be contaminated by chemical spills and other industrial accidents. Events like gas well blow outs, illegal dumping of fracking waste, and natural disasters like floods that can disperse contaminants across the land surface and into waterways have all occurred on the mainland.
The NSW EPA issued fines and warnings to two CSG operators for pollution of the Pilliga state forest. Testing of samples taken from areas near CSG developments in the Pilliga detected heavy metals up to 37 times higher than natural levels.
Early in 2015 scientists in the US found that fracking could lead to greater levels of soil contamination than had been previously understood. They discovered that certain chemicals in fracking wastewater trigger the release of particles known as colloids from within soil. Colloids bind pollutants and heavy metals to sand and soil particles.
The same properties that make frack fluid effective at extracting gas from shale also makes it hyper-effective at releasing colloids. The researchers found that when they flushed sand with de-ionised water about 5 per cent of colloids were released, but flushing with flowback fluid caused a release of between 32 and 36 per cent. Increasing the flow rate mobilised an additional 36 per cent of colloids.
When the wastewater surges back to the surface after a high pressure injection and spills occur, this enables pollutants that are bound to colloids to leach out and contaminate the surrounding soil. The researchers noted that wastewater spills are quite common.
Intensive, invasive fracking infrastructure also destroys farmland. A gas well pad takes up between 3 and 5 hectares. Wastewater pits or damns constructed to hold flowback, the toxic blend of chemicals that include hazardous substances, heavy metals and radioactive materials, have an extensive surface footprint. Once destroyed by compaction, once eroded or mined, soil that was previously arable farming land cannot be easily brought back to production.