Runoff carries all sorts of things into waters, and I think the issue is particularly bad when you have large denser areas like Seattle, since the concentration

Runoff carries all sorts of things into waters, and I think the issue is particularly bad when you have large denser areas like Seattle, since the concentration of unwanted chemicals in local waters can be huge. For example opioids from Seattle’s street level drug abuse can be found in local marine life: https://www.npr.org/sections/thetwo-way/2018/05/25/614593382/traces-of-opioids-found-in-seattle-area-mussels https://www.npr.org/sections/thetwo-way/2018/05/25/614593382...