A few years ago I had a call from a woman wanting to know about mercury in
fish as she was eating no meat but lots of fish. So I went to the library to
see what I could find.

Most of the information I could find (just two or three articles) were about
methylmercury.

One case study article I found at the medical library was about a, was it
Pakistani?, woman who had toxic levels with neurological consequences. Her
infant went to the hospital with her, continuing to breastfeed, showed no
signs of the toxicity.  The child was breastfed well into her second year of
life, if my recall can be trusted.

Mardrey Swenson

I think it was published in the '80s.