|Train lines have created historical contamination|
It has long been known that contamination doesn’t necessarily stay where it was originally placed. Those unlined trenches across the country where coal tar and other pollutants were casually discarded during an era of ignorance, eventually released their volatile contaminants to the surrounding soils, and ultimately to the ground water.
Then too, as commenters to some of the posts here have noted, the structures of the earth itself act as vectors to carry the contaminants deeper and many times in illogical directions. Highly fractured rock below the soil surface will allow substances to travel in certain paths acting almost like pipes. But what about pipes?
Playing out right now in St. Clair Shores, Michigan, is an investigation into the ways utility lines might be helping to channel contaminants. Polychlorinated biphenyls (PCB) contamination was found there 10 years ago, but the source has been difficult to discover. So the Environmental Protection Agency is taking soil samples along the routes of utility lines to see if it can discover the source. A certain amount of compaction happens as utility pipes are laid and when they are backfilled the exterior surfaces of the pipes don’t blend with the surrounding soil. This creates a place where fluids can easily travel.
Of course, following the utility lines can work both ways. It can be used to find the contamination source and also to offer clues as to where it is going next.