I believe that there are...I haven't gotten sick but with all of the pollution being pumped from and running off into the rivers (and eventually the ocean) there's bound to be...one example, we know all to well that mercury accumulates in higher concentrations as you move up the chain and never dissipates...DDT (also cumulative) was a problem for a while and other countries may still be using it without regard...as long as there is big industry, lawn chemicals, etc. there will be toxins in our food chain