Years ago living in So Calif. a good friend calls me up, and wants to go fishing in the Salton Sea, famous for big Corvina and Tilapia, there are days where every cast is a pretty big fish. However we had late winter storms and flooding occurred breaching the Mexicali tiny dam. Mexicali is south of the US/Mex boarder, the Salton Sea is a basin below sea level, thus instead of like the Colorado river which runs south, the river from Mexicali drained into the Salton Sea. Due to the flooding raw sewage from not only Mexican residential but also industrial sewage was flowing into the Salton Sea. The lower end of the Salton Sea was closed for a couple of months (SS is 35 mi long). In addition the way the Salton Sea gets its water is from Imperial Valley irrigation run off which is heavy in fertilizer chemicals, (high in Selenium and other salts). In fact the Salton Sea is saltier than the ocean.
I thought I would call Imperial Valley public health dept. I got lucky and actually talked to the guy responsible for reports, and was involved in the testing. At first he would only give me the official skinny, that the Salton Sea by Gov. standards was now safe. Then I asked him specific question about toxicity levels on certain chemicals, and especially at the lower end of the lake. The story revealed a public health hazard, but because of recreation and local politics, the readings were averaged with the other half of lake making it overall safe. He confirmed that fish were dying and that feces and toilet paper were floating on the surface, that the bottom of the lake at from the river entrance out about 5 miles was one giant sludge muck of contaminated waste build up. The final question, "How many kids do you have? A: 3. Would you take them swimming in the Salton Sea? Would you feed fish caught in the Salton Sea to your children? NO!
I called my buddy and told him what I found out. The Sport Fishing News paper we both subscribed too had fantastic stories of 20-30 lb Corvina being caught. He couldn't resist he was going, he called 2 days later, they had a huge catch almost all the fish over 10 lbs, he wanted to give me about 50 lbs of fish. I thanked him but gave him a firm NO.
About a 6 months later 60 Minutes did a piece on the Salton Sea