Pesticides that kill salmon in minute quantities. Most will wash down to the ocean. but many won't break down.

Not to mention the likelihood of these poisons being inadvertently consumed by humans.

It would be interesting to find out which pesticides are being used in Washington DC, or Texas. Many of the pesticides do not break down and Persistent Organic Pollutants accumulate, in the environment and the food chain. The higher in the food chain, the more POPs accumulate. The Authorities have banned them for this reason. Just test marine life or humans for dioxins, and other similar chemicals.. The results can be frightening. (Any relationship between pollutants and popularity, is completely co-incidental-Unless discussing Poliutics.