The filthiest waterway in Brooklyn isn’t the Gowanus Canal — it is Newtown Creek! So says the only man who could possibly know for sure: Christopher Swain, the one person in history to successfully swim both toxin-filled inlets.
http://www.brooklynpaper.com/stories/39/1/dtg-newtown-creek-swim-complete-2015-01-01-bk.html