**3. Program Genesis**

As far back as the early 20th century, salinity and inorganic constituents have been the primary constituents of concern in the municipal and agricultural beneficial uses of Delta source waters. Federal legislation in the 1970s, including the Clean Water Act of 1972 [27] and the Safe Drinking Water Act of 1974 [28] led to the regulation of a broad range of water quality constituents of concern in drinking water supplies and in treated drinking water. Coincident with this period, researchers demonstrated the formation of THMs during chlorination [29,30], a conventional treatment process for disinfecting drinking water. Later investigations suggested a potential relationship between THM occurrence and increased incidence of cancer among exposed populations [31]. In 1979, the USEPA promulgated a maximum contaminant level (MCL) of 100 μg/L for total THMs [32].
