Here are two articles I'd like you to read. You may need some information from them for your homework.
Mercury Pathways to Fish by EPRI (Electrical Power Research Institute).Text or PDF The pdf file take a little longer to download, but has some neat color pictures and graphs that you don't see on the text version.
The second is Pirate Fear . This is a Scientific American article with hyperlinks to other information.
End Sub-module 12C