More than 30 tons of toxic PCBs will be dredged from 19 miles of Wisconsin’s Fox River if a cleanup plan announced yesterday wins public support. To atone for decades of dumping the toxins, a consortium of seven paper companies would pick up the $308 million price tag for the cleanup of the Fox, which is the leading source of PCBs flowing into the Great Lakes. Enviros said the plan would be a good first step, but they pointed out that only parts of the river would be dredged. Portions of the river and adjacent Green Bay not covered by the plan would be on their own to recover from the more than 75 tons of PCBs that would remain after the cleanup. The state Department of Natural Resources will take public comment on the plan through early December.