I would not eat anything caught around Ruston. Smelter ring a bell? 
Being as efficient as a crabs filtering system is - I dont think It really matters where its caught.
True but can they filter arsenic and such? Alot of hidden buried toxins around there. Did you see the EPA in their white suits on lookout towers???
People can jump to all kinds of conclusions. Its really nothing that concerns me. Ive never even got an upset stomach from things ive harvested. When I do at that point I may start to care buut probably not. If i was worried about everything in the world like that I probably wouldnt be able to eat anything. Pesticides on fruits plants and veggies, mad cow in beef, chicken thats poorly raised and dispatched by smashing against walls. Meh not really concerned lol