Contaminant Candidate List and Six-Year Drinking Water Review

The Safe Drinking Water Act requires the U.S. EPA to list every 5 years the priority chemical and microbial contaminants that are known or expected to occur in public water systems so they can be ranked for research and possible future regulation. Cadmus provides expertise in chemistry, microbiology, risk analysis, toxicology, and decision analysis to help EPA implement its multistage Contaminant Candidate List (CCL) classification process. Working with EPA and a National Drinking Water Advisory Council workgroup, we:

• Evaluated over 200 data sources to identify thousands of potential drinking water contaminants.
• Developed a relational database to accommodate and link a wide range of data types to support later stages of the classification process.

During the process’ second stage, we helped screen the potential contaminants for health effects and occurrence to create a preliminary CCL. In stage three, we are characterizing the common health effects and occurrence attributes of candidates and using innovative, prototype statistical algorithms to classify and prioritize the preliminary list for consideration for the CCL. We also are helping the EPA Office of Ground Water and Drinking Water:

• Evaluate microbial characteristics — genetic factors, surface proteins, or toxins — to predict the virulence of the pathogens.
• Conduct research using bioinformatics to support future models that might use genomic information to identify emerging waterborne pathogens.