Question

A small town in New Mexico discovers that a chemical plant outside of town recently learned that one of their underground pipelines had broken without their knowledge and had been leaking a toxic organic compound for over a month. The spill occurred 5m below the surface in a sandstone above a thin shale bed in the local bedrock. The beds are flat lying and this shale crops out 200m from the chemical plant. The town gets is water from deep wells, about 300m deep. What should the town worry about from this spill?

Answer 1

The major concern for the town in the described scenario is that the freshwater they use from the wells may get polluted by toxic organic compounds that will make the water unsafe and dangerous for usage. The toxic organic compounds have been released for a whole month bellow the surface in a sandstone layer. The sandstone is very easy to penetrate through, so the toxic matter will easily go down through it. As it reaches the lower layers, the shale bedrock comes as the only barrier between it and the freshwater used from the wells. The shale is a soft sedimentary rock, so with enough accumulation of the toxic organic compound it will soon have cracks and the toxic matter will reach the water. Once it mixes with the water, it will pollute it, thus making the deep wells unusable, and the people from the town will be left without their primary source of freshwater which can turn into a catastrophe.