According to ths gov report, we've seen a massive reduction in toxic metals and other unwanted chemicals since the 80s, with the sole exception of Nitrates which peaked in 1998 and have been in the downhill since.
This does not jell very well with what I've been hearing about water companies dumping into the river, so I wonder if the gov is protecting itself with a false report, or that the report is true but the recent dumping is not significant but alarming as a general trend that might balloon into something serious?