Andy, You are really on to something by highlighting some of the ecological issues with the lower Raritan. Try to garner some support from the American Littoral Society. They do beach and other ecological clean ups.
Tim@LittoralSociety.org
Bill@LittoralSociety.org
Maybe they have some resources or might be looking for a project for next year. All things float downstream so eventually all that you discovered will make their way into the bay and beyond. It's worth an email.