It's Portland's dirty little secret, but one that shouldn't be much of a surprise to anyone who's spent any time on the Eastbank Esplanade: The Willamette River is a filthy, environmental disaster. Next week, a state senate committee could move forward with a plan to clean it up—or objections from polluters could bog it down.

For decades, the Willamette River has served as a convenient dump for industrial companies and mills, sewers for the cities that dot its banks, and a runoff destination for agricultural water. The result: A nearly six-mile stretch of the Willamette through the north half of Portland is a designated Superfund toxic waste site, and chemicals like mercury show up in river sediment and fish tissue. Such unpleasantness landed the Willamette in the number-three spot on advocacy group American Rivers' most endangered rivers in 2006.

In the 1970s, a little thing called the Clean Water Act was implemented to curb the problems. But Oregon's state government managed to find a way around it, by allowing for "toxic mixing zones"—areas along the river where polluters can dump to their hearts' content, with the idea that the river itself will dilute the chemicals down to "acceptable levels."

"The mixing zones don't meet the original intent of the Clean Water Act," says Willamette Riverkeeper's Travis Williams. "We want to prevent putting chemicals into waterways, but then the Department of Environmental Quality says, 'But here are sections of the river where you can!'"

In response, the Oregon Senate Committee on the Environment and Natural Resources is considering Senate Bill 737, which would phase those toxic mixing zones out over several years, putting an end to the loophole that allows cities and businesses to continue polluting the river.

But, as with all things in Salem, political realities may get in the way of that goal. A work group has been formed between environmental groups, representatives from industries (like paper mills), and the League of Oregon Cities to find a compromise on the bill. The group is expected to deliver its recommendations later this week, in advance of a public hearing in Salem on Tuesday, April 24.

Ultimately, the group may "gut and stuff" SB737, replacing it with something else entirely. Until then, it's difficult to gauge how effective the effort will be.

"The use of toxic mixing zones looks to most people like a method for dumping chemicals into the water," says State Senator Brad Avakian, chair of the committee. "But it's more complicated than that. If you want to really clean up the river, you need a bill that will work."

At what point, then, do lawmakers push for a remedy, regardless of what the industry thinks?

"That all depends on whether the work group gets its work done," Avakian says.