Day 12: Toluene
Toluene is an aromatic hydrocarbon that when consumed in drinking water can cause severe problems with the nervous system, liver and kidneys. It is highly soluble in water, and although there is ongoing debate about its carcinogenic potential, it is highly regulated. The current EPA maximum content guideline is 1 part per million, where the WHO sideline is .7 parts per million.
The compound was first discovered in 1837 by Polish chemist, Filip Walter, by distilling pine oil. It has been found to be naturally occurring in low levels in crude oil, and is used today in chemical reactions that refine fuels, often to remove impurities from goal, and in the production of gasoline. More recently it has been acknowledged as a key ingredient in fracking fluids, and has been discovered in groundwater supplies in areas where the safety and proper maintenance of natural gas excavation rigs has come under criticism.