"notbob" > wrote in message
...
> On 2017-11-10, cshenk > wrote:
>
>> Wow, I'd not have thought of the goldrush causing mercury issues!
>
> Oh, major!
>
> I ate some CA crawdad tails waaaay back when, long before I knew.
> But, mercury poisoning is a major problem in CA. All the mines (and
> miners)
> used mercury to separate the gold from the tailings (amalgam).
>
> <https://en.wikipedia.org/wiki/Amalgam_(chemistry)#Gold_extraction_.28mining.29>
>
> I recall then they opened the new San Mateo bridge. They left part of
> the old SM bridge standing, fer fishermen. They also put up a buncha
> new "Do Not" signs. The one "Do Not" I mostly recalled was, "Do not
> eat more than one fish per week". This warning later became SF Bay wide,
> due to heavy mercury poisoning in the CA Delta.
>
> nb

Yep, definitely a problem in the Sacramento River, all the do not signs,
especially pregnant women and so forth.

Cheri