By Shelley Levin, Middle School Faculty

In science, the 6^th graders have been studying ecology through the case study of the Southern Resident orca population.

This population, which lives locally year-round in the Salish Sea, are in decline due to boat disturbance, biomagnification of toxins like PCBs, and lack of their primary prey, Chinook salmon. To better understand how wastewater and stormwater affect the orcas, recently the 6^th grade visited Brightwater, a King County Wastewater treatment plant and education center.

On the field trip, the girls got to experiment as microbiologists and chemical engineers to see how we humans can—and can’t—clean up our wastewater, which is eventually returned to the Puget Sound. We also toured the wastewater treatment plant and saw firsthand how trash, organics, and microbes are removed in the treatment process. Unfortunately, the treatment process does not remove chemicals, like the PCBs affecting orcas and their prey. The solution our 6th-grade engineers determined? Avoid putting chemicals down the drain in the first place and clean up our streets to avoid toxic runoff in stormwater.

Next in science class, the 6^th graders will finish up letters to their state legislators advocating for an action that will help our Southern Resident orcas. Not surprisingly, many are choosing to write about ways to reduce toxins entering the Salish Sea!