The Environmental Protection Agency's annual "report card" for Boston’s three major rivers the Charles, Mystic and Neponset gave some As and Bs but highlighted some problems areas. Challenges include sewage overflows, stormwater pollution, low water levels and increased heat from climate change.
The annual water quality grades for the three rivers that flow into Boston Harbor the Charles, Mystic and Neponset rivers were released on Thursday, revealing a mix of progress and sliding scores across the region.