WASHINGTON, July 1 -- Sen. Jeff Merkley issued the following press release:

Congressman Raja Krishnamoorthi (D-IL), Congresswoman Janelle Bynum (D-OR), Senator Jeff Merkley (D-OR), and Senator Cory Booker (D-NJ) on Tuesday led a bicameral letter, joined by 53 of their colleagues, urging Environmental Protection Agency Administrator Lee Zeldin to add microplastics to the agency's recently published Sixth Unregulated Contaminant Monitoring Rule (UCMR 6). The lawmakers argue that EPA should begin monitoring microplastics in America's drinking water, citing a growing body of research linking the emerging contaminant to serious adverse health effects.

In their letter, the lawmakers note that emerging research has found microplastics throughout...