Guam EPA updates risk-assessment guidance; public comment period open through Dec. 17

Agency staff reported that the Guam EPA risk-assessment document has been revised to clarify monitoring and notification procedures for treated water systems and to align some language with U.S. EPA pesticide guidance. The update specifically amends sections 5 and 6 to provide more flexible criteria for lifting a "do not drink without treatment" order that previously required a running annual average, which could have delayed lifting advisories for multiple quarters.

Staff said the draft was released for public comment on Nov. 26 and will remain open through Dec. 17; a public hearing is scheduled for Dec. 17 at 1500 hours. The document and a summary were made available on the agency website and sent directly to public-water-system operators on the island.

The agency also briefed the board on ongoing site-investigation activity at the site referred to as "Old 1". Staff said they have met with U.S. EPA and the Guam Waterworks Authority, engaged hydrologists to better target sampling, and requested a Brownfields assessment (described in the meeting record as under review at U.S. EPA headquarters) to support a more thorough investigation. Staff said they plan additional sampling focused around an area labeled Y-15 and are coordinating with public health and the Agency for Toxic Substances and Disease Registry to consider epidemiological approaches appropriate for community needs.

Staff cautioned that epidemiologic studies often fail to show clear correlations and said the agency is trying to design studies and data collection that will be useful to the community. Staff invited board members to review compiled public comments and indicated the board would discuss the item again after the comment period and any revisions.