Sturgeon migrate so they are not considered "resident". They eat the recently dead, often the remains of other migratory fish, They are transitory through the areas with toxin issues.
Resident fish such as bass, carp, pan fish, cat fish and such pose a great danger as they reside in the contaminated zones.
The serous problems are in the sediments of both the Willamette and lower Columbia. Most of the PCBs, Dioxin, Arsenic, and heavy metals contamination are a legacy of the Liberty ship construction and the Kaiser ship yards of WWII.
It's in the goo on the bottom and the best safety measure is to not disturb it.
Our grand parents faced a world in crisis, they did what they had to do; the contamination is the legacy our region is left with. It's impossible to dredge the length of the problem with out huge environmental and economic costs.
It may well take another Missoula Lake flood to scour all the crap out....
Glacial Lake Missoula and the Ice Age Floods
So IMHO....... Yes they are safe to eat, as with anything; in moderation.