DOVER, N.H. — A group of New Hampshire municipalities says it’s going to sue the U.S. Environmental Protection Agency over the details of efforts to control nitrogen pollution in the Great Bay estuary.

The Great Bay Municipal Coalition, including the mayors of Dover, Portsmouth, Rochester and other official officials held a news conference Monday in Dover to discuss what they believe are pollution control requirements that are too demanding and expensive.

Nitrogen discharges act as fertilizer that causes plant growth in waterways.

Fosters Daily Democrat quotes Portsmouth attorney E. Tupper Kinder as saying the communities are spending hundreds of millions of dollars to ensure wastewater treatment plants are running efficiently. The dispute is over whether the EPA and New Hampshire officials are burdening the communities with requirements that have no environmental benefit.