The Columbia River has been contaminated with radioactive waste from Hanford for decades. No one is saying how much waste has contaminated the river since the nuclear site was first developed, but an EPA official recently admitted that radioactive waste was flooding river:
Karina Brown. June 8, 2017. Radioactive Waste Still Flooding Columbia River, EPA Says. Courthouse News, https://www.courthousenews.com/radioactive-waste-still-flooding-columbia-river-epa-says/The Columbia River is surrounded by agriculture at various points in its course, as you can see in this map http://www.lpi.usra.edu/publications/slidesets/humanimprints/slide_23.html
KENNEWICK, Wash. (CN) – Groundwater contaminated with radioactive waste from the decommissioned Hanford nuclear facility in Washington state is still “flowing freely” into the Columbia River, a program manager with the U.S. Environmental Protection Agency said at a meeting of the Hanford Advisory Board.
The announcement came as part of a five-year review of cleanup measures taken at the Superfund site. Officials with the EPA and the Department of Energy said at a meeting Wednesday that the review showed most of the cleanup actions at Hanford were properly “protective,” meaning the public was shielded from the worst of the site’s estimated 500 million gallons of potentially radioactive waste.
Risk assessments have been inadequate, as you can read here:
Russell Stewart. The Effect of Weapon Production at the Hanford Nuclear Reservation. Stanford, http://web.stanford.edu/class/e297c/war_peace/atomic/heffect.htmlIs it safe to eat food irrigated with Columbia River water?