Tear gas residue is not significantly impacting Willamette River, Portland report concludesBy Monica Samayoa (OPB)Sept. 11, 2020 4:29 p.m.The study was based on samples from stormwater and sediment from downtown Portland storm drains.📨 Daily news in your inboxSign up today for OPB’s “First Look” – your daily guide to the most important news and culture stories from around the Northwest.EmailPlease leave this field blankSign up