>>Tom Bridgeland wrote: I read somewhere once that some scientist measured
the mercury in fish before the industrial age (I don't recall how) and found
no difference.

Back in 1972 the state of New York issued a warning about mercury
contamination in the food fish caught in Lake Champlain. They (If I remember
correctly) banned the eating of some species and recommended limitations on
others. A few years later they rescinded everything. Seems that newer more
sensitive tests were skewing the data. When they tested dinosaur bones at
the Museum of Natural History they found high concentrations of mercury.

Tom Barber