Final answer:
The chemical contaminant commonly found in local water supplies near fracking sites is methane, which can present health risks if it enters the drinking water.
Step-by-step explanation:
In reference to the chemical contaminants found in local water supplies near fracking sites, the correct answer is methane. This is a common issue associated with hydraulic fracturing, which is the process used to extract natural gas and oil from deep underground. One of the primary concerns with fracking is the potential for chemicals to seep into the water supply, and methane is often cited as a contaminant of concern. Methane is an explosive gas and can present significant health risks if it contaminates drinking water. In addition to methane, other chemicals and substances such as heavy metals, brine, and fracking fluids may also be found in water supplies near fracking sites, raising concerns about water quality and safety.