1. Microbial and Disinfection Byproducts (MDBP) Rules Revision Update
EPA is seeking input and information to inform potential regulatory revisions of eight National Primary Drinking Water Regulations (NPDWRs) included in five Microbial and Disinfection Byproducts (MDBP) rules following the third Six-Year Review. EPA hosted an initial virtual public meeting in October 2020 to solicit input on further improving public health protection from MDBPs in drinking water. Throughout 2021, EPA sought input relevant to any potential rule revisions through additional public meetings focusing on topics identified through public comments and information. EPA has requested the National Drinking Water Advisory Council (NDWAC or Council), a Federal Advisory Committee (FAC) established under the Safe Drinking Water Act (SDWA) of 1974, to provide the agency with advice and recommendations on potential revisions to the MDBP Rules. In addition, to support the work of the Council, EPA asked the NDWAC to form a working group to explore specific issues and identify potential MDBP rule revision options for the Council to consider in making recommendations to EPA. This presentation will provide an overview of the regulatory process, summary of public engagements, topics under consideration, and timeline with next steps.
2. Challenges and Perspectives of Studying Water Storage Tank Ecosystems in Distribution Systems
Finished water storage facilities are tanks or reservoirs used to store water that will undergo no further treatment. Storage tanks are vulnerable to contamination, and excess water retention time may cause depletion of disinfectant residual which creates an environment favorable for microbial contamination. The current presentation evaluated the use of a field-based sampling and a pilot-scale experimental approach to understand the ecosystem of water storage tanks. An integrative approach was utilized to characterize the storage tank ecosystem and their microbiome. Adaptive traits that allow microbes to persist and respond to environmental changes, virulence and antimicrobial-associated genes are encoded at a genetic level. It is important to understand the biotic and abiotic characteristics of these systems which amplify the potential public health risk relative to the distribution system.