The Northwest and Middle branches of the Patapsco  River, which form Baltimore's harbor, are littered with trash, unfit to swim in and plagued by algae blooms and fish kills. In places, the water is dirty enough to make you ill if it gets into a cut or you touch it and then touch your nose or mouth. The bottom is a toxic wasteland that makes many fish caught in the harbor unsafe to eat.
And even though the harbor is not as polluted as it was in the 19th and early 20th centuries, when factories spewed untreated waste into the water, conditions are nothing to brag about. The Patapsco and Back rivers, which drain much of the metro area, received failing grades on last year's report card on the Chesapeake Bay's  health. Baltimore's harbor is arguably the most polluted spot along the estuary — and, by some accounts, the most neglected.
Now, though, pressure is building to do something about it. Drawn by the real estate renaissance along the waterfront during the past 30 years, stretching from Canton and Fells Point  around the Inner Harbor  to Locust Point , a new generation of residents and workers is agitating to clean up the harbor."