Date of Award
Master of Science (MS)
Civil and Environmental Engineering
Every 5 years the USEPA is responsible to publish a list of unregulated contaminants that are known or expected to occur in public water systems in the United States that may pose a risk on public health. This list is known as a contaminant candidate list (CCL). This year it is expected that the USEPA is to publish the 4th such list of the CCL or CCL4. Candidacy to be on the CCL4 is based on a compound’s occurrence in the environment, public health toxicity and recommendation from expert opinion. Methods to qualitatively determine occurrence and toxicity for compounds were developed in this research and based off USEPA methods. This process involved looking at a large range of chemicals/compounds found in the environment from varying groups such as: disinfection bi‐products, pharmaceuticals, pesticides, inorganics, volatile organic compounds, industrial and cyanotoxins. These compounds may have been included on previous CCL lists or are contaminants of concern currently found in the drinking water industry. Data approaches such as the creation of a master sheet, space diagrams and numerical algorithms ranked compounds based on occurrence and toxicity. These data approaches, along with others, were then provided to an expert panel (TAW) that considered all of these tools, in addition to others, to develop expert opinions about the top candidates for the CCL4. Results from this approach categorized the compounds and binned them into 4 groups. Of the 122 studied compounds, recommendations for the USEPA are as followed: Group 1. Top priority for inclusion in CCL4 (7 compounds and super‐group DBPs). Group 2. Recommend inclusion on CCL4 but insufficient data currently for regulatory determination (10 compounds). Group 3. Recommend inclusion on CCL4 based on sufficient data for negative regulatory determinations (33 compounds). Group 4. Recommend not to include in CCL4 (56 compounds).
Bench, Ryan Worth, "Development of AWWA Recommendations for CCL4 Prioritization and Process" (2015). All Graduate Plan B and other Reports. 500.
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