== Why Safe Water Drinking Act is relevant to PWD article. == 

 The Safe Water Drinking Act (and it's Halliburton loophole) is relevant to PWD article because it prevents the investigation and regulation of the contents of fracking fluid, including the radionuclides used as tracers. One of the most commonly used ones, iodine-131, is showing up in drinking water in Philadelphia. They have tracked it to water treatment facility effluent, and found it in some rivers, but have not conclusively determined its sources. They have ruled out nuclear facilities and hospitals. There is a new approach to tracking such substances which uses a form of chemical "fingerprinting" to identify the sources of contaminants. A similar technology has allowed researchers to identify the source of methane leaks in Denver as well. In any event, the regulation is very relevant to Philadelphia's issues, especially since there is a history of fracking wastewater disposal in the eastern half of the state, including in Montgomery and Buck's counties.