Water samples taken overnight confirmed that chemicals leaked into the river when a 900,000-gallon tank containing caustic “white liquor” ruptured. LONGVIEW, Wash. — The Columbia River was contaminated by chemicals from the tank rupture at the Nippon Dynawave Packaging facility in Longview, officials confirmed Wednesday. The extent of the contamination is unknown. Water samples taken overnight confirmed that chemicals leaked into the river when a 900,000-gallon tank of “white liquor” ruptured, with an estimated 25,000 gallons of the highly caustic solution still inside, officials said at a Wednesday briefing. Officials estimated that the tank was about 60% full at the…