http://www.jrn.columbia.edu/studentwork/cns/2002-07-07/696.asp

Here's a little excerpt to peak your interest
Between 1947 and 1977, General Electric dumped an estimated 1.3 billion pounds of polychlorinated biphenyls (PCBs), a carcinogen, into the Hudson River. In 1976, the Department of Environmental Conservation banned all fishing on the river, and it wasn't until 1995 that a catch-and-release program was allowed