SNOQUALMIE, Wash.—Out in the Snoqualmie forests of eastern King County, on the west side of the Cascades, the ground is black and mucky. It's an unnatural scene with a toilet-bowl stench.
And it comes from tons upon tons— about 120,000 tons a year—of sewage sludge that King County, home of Seattle and more than 2 million people, disposes of annually in these forests and on farms and rangelands of central and eastern Washington.
This sludge, known euphemistically as "biosolids," consists of semi-liquid waste obtained from the processing of municipal sewage. The goal of this process is to obtain clean water to release into the environment, and thus, the cleaner the water, the more toxins and contaminants are retained in the sludge. This sludge used to be dumped into the ocean, but because of its toxicity this process is banned. Instead we now spread it in our forests and on our agricultural lands.
The spreading of this sludge carries considerable risk and should be stopped. As scientists, we are increasingly concerned with this reckless practice.