Dr. Know

I see a lot of people fishing around the St. Johns industrial area—are the fish safe to eat? (Are any Willamette fish safe to eat?)

—Chester B., Portland

Depends on your definition of "safe." Do they explode when you bite into them? Not usually. But if you're looking for assurances beyond that about the culinary safety of Willamette River fish, I'm afraid you're going to be disappointed.

The Oregon Department of Fish and Wildlife publishes something called a "Fish Advisory: Consumption Guidelines," which begins, rather rosily, "Fish are great sources of omega-3 fatty acids, protein, vitamins, and nutrients," before settling down and more or less acknowledging that they're also great sources of mercury, dioxin and PCBs.

According to Travis Williams, executive director of Willamette Riverkeeper, environmental toxins tend to accumulate in the fish's fatty tissues, and the Fish Advisory includes a helpful diagram showing the reader how to remove the fatty deposits along the fish's back, sides, belly and skin. If this is starting to sound to you like "just eat around the poison," well, I'm not going to argue with you.

That said, not all toxic, glowing mutant fish are created equal. Williams notes that resident species—that is, those that spend their whole lives in the Portland harbor, freebasing dioxin and casting paranoid glances out the window—tend to be higher in toxins than migratory species, who might just huff a little DDT on their way to a party.

This means fish like chinook and sturgeon are sort of OK, while smallmouth bass, crappie and catfish are pretty iffy. While the official word is that up to one serving a month of the latter is OK for "healthy adult males," you'll pardon me if I opt for the chicken instead.

Send them to dr.know@wweek.com.

WWeek 2015