Communities along the shores of the Merrimack River, and the health of the people who live in them, are the focus of a new study by a research team at Boston University. The study focuses on "combined sewer overflows", events that are triggered by heavy rains and severe weather that send thousands of gallons of harmful bacteria and sewage into the river. Dr. Beth Haley, a BU URBAN Trainee, joins Nichole this week to talk about the impact of these overflows on residents and what can be done to mitigate this problem.