Nitrogen pollution in Casco Bay is coming from land-based sources, says conservation group

MAINE PUBLIC • April 27, 2023

Nitrogen levels in Portland Harbor and Casco Bay indicate that land-based nitrogen sources need to be regulated, according to the Friends of Casco Bay. They said water samples taken during a rainy day resulted in higher nitrogen levels due to storm runoff than those taken during last summer's dry spell. The data are being used to help the state create threshold values of nitrogen for wastewater discharge licensing.