Blues Frog

I'm curious about parts of the American west where there were gold mines that used mercury to separate gold in the 1800s. Is there still lots of mercury in the mountain streams below the old mines? I have heard that the gold panned from some streams these days was silver in color due to the remaining mercury. Maybe I am mixing something up here. But the water filters I see for sale don't say they will remove all the chemicals. It makes that a concern to me. TIA

Mr. Embrey

Damn, now I'm curious too.

Bekologist

mercury is quite heavy. don't dig when you're filtering and you'll be fine.

jamawani 

You have more to worry about from the cattle upstream - -
And the hikers.

cyccommute 

Mercury metal is heavy but mercury ions aren't. The amount of mercury in the water would depend on a number of factors such as the acidity of the water near mining activity, the amount used, temperature of the water, etc. If, as Blues Frog says, the gold is silver, that means that there is a huge amount if mercury present. I doubt, highly, that anywhere has that much mercury around. Not disturbing the sediment would help but the mercury that you have to worry about is the stuff that is dissolved.

But mercury would be the least of your worries in mining districts. There are, roughly, 20 heavy metals that cause problems in mining districts. Many are far more reactive and far easier to get into the water than mercury is. Arsenic, for example, forms salts readily and then can dissolve to fairly high concentrations making it more toxic than mercury which is less reactive and less soluble.

With a proper filter, biological hazards are easy to deal with...it's simply a matter of particles and filter size. Heavy metals can't be filtered out because the particles are far too small to filter. If you had a filter small enough to trap heavy metal salts, you couldn't pass water through it.

The rule of thumb I use is that if the waters have trout* in them...and/or fishermen trying to catch the fish...the stream is probably alright to filter from. If, on the other hand, the stream is rusty looking,



flowing out of an obvious mine or hasn't got trout in it, you might want to look for another source.

*I pick trout because trout are damned delicate. Catfish, carp and bass can tolerate much higher levels of nasties and still survive. If the waters have a healthy population of trout, the water is pretty good. The Arkansas River in Colorado, for example, has a very health trout population even with a small amount of mine drainage. Clear Creek below Central City/Black Hawk has almost no fish (and hasn't for years) because of mine drainage.

curbtender

I'd say mercury would be more of a problem in the delta area. The winter flows tend to scour the mountains out pretty well. There are some hydralic strip mines that have some nasty looking ponds around them, but most people wouldn't be filling thier canteens there. As stated above, just collect from the fast moving water and don't dredge up the sediments.

fietsbob

use Municipal water, bring it from town, the west is pretty well settled by now.

caloso

Y' c'n turn the radiator on
Whenever you want some heat.
With ev'ry kind o' comfort
Ev'ry house is all complete.
You c'n walk to privies in the rain
And never wet your feet!
They've gone about as fur as they c'n go,

Men:
Yes sir!
They've gone about as fur as they c'n go!

positron

good background info:

https://www.groundtruthtrekking.org/I...eDrainage.html

I steer clear of most creeks in the rockies unless there are fish/plants etc.

cyccommute 

The article seems to be only concerned with acid drainage and, I believe, is completely wrong about the levels of acid. Battery acid is around 30% sulfuric acid by weight (70% water). For a mine to produce acid concentrations of that amount, it would have to make unbelievable amounts of acid per minute for even a trickle of water from the mine. If, for example, the mine leaked out 10 gallons of water a minute, it would have to produce 43 pounds of sulfuric acid each and every minute to reach those levels. You might be able to produce that amount of sulfuric acid in an industrial process but natural weathering of rock just can do it. 30% sulfuric acid would be highly toxic too.

The acid in acid mine drainage is the least of the problem. The acid mobilizes heavy metals by dissolving and reacting with them. At 30% sulfuric acid concentrations produced at the amounts of water flow these mines can discharge, it would eat a mountain down to stubs in a matter of days.

Don't get me wrong, mine acid drainage is a problem but it's not as big a problem as the article suggests. Certainly not 1000 times as concentrated as battery acid.

Mr. Embrey

Wow, thanks for the info. My grandfather used to go to some of the old mine areas in Colorado and Nevada and pan the streams. He still has all of his old equipment. I've been tyring to get him to go back with me and show me a few things.

jayr

You don't really have to worry about Acid mine drainage in the Gold country streams. There are very high levels of Hg. in the Sierra foothills however it is not readily available for uptake in the solid form and levels of dissolved Hg. even in very highly polluted streams isn't anything to worry about. Hg. has to be methylated to become bioavailable for uptake into an organism. That generally happens in anoxic environments. Streams are not normally anoxic, and if they are you would look at them and not want to drink out of them anyway. The fish on the other hand, including trout can be something to worry about. Methyl Hg bioaccumulates in organisms so what you take in is with you your whole life and given enough uptake can cause nervous system damage. Fish, especially high trophic level fish (Bass, Catfish, Brown trout, large rainbow trout) can and do in the mother load area lakes and streams contain Hg at levels that far surpass human health guidelines and still look fine. Even then if your an adult male (not a woman of child bearing age, child etc). a meal or two every so often is probably not much to worry about, though we do have some waters where it is not recommended that anyone eat any of the fish. A side note to that is the hatchery fish that are planted in the area have very low Hg. levels so they are safe to eat.
Bottom line is you don't have to worry about Hg. in the water. It's not available for uptake in that compartment. Fertilizers and pesticides from the wine grapes, cattle grazing, and leaky septic systems to a lesser extent should be something that concerns you more.

mycoatl

I spent a few weeks on an archaeology dig at an old mining town in Washington's North Cascades. The only concern about drinking water there was arsenic, but the stream had been tested and was OK for the length of time we would be there. As snowmelt and rainwater percolated through all of the mining tailings, it kept dissolving arsenic so even 100 years after commercial mining ceased, it was still a concern.

cyccommute 

Fertilizers and pesticides as well as dissolved chemicals are a concern because you can't filter them out easily. Biological materials from the south end of a north bound organism...including the stuff from the back of a cow or the end of a septic tank...shouldn't be a concern if you are using a water filter.

The Impossipede

cyccommute,

You seem to really be on top of this stuff. Would an activated charcoal component to a filter do anything to address pesticides, fertilizers, and metals?

cyccommute 

Maybe for the organics...but it has it limits. There's not much quantity of activated charcoal in the filters and it could get overwhelmed quickly if the concentration of organics is high.

The charcoal might trap some metals but it does poorly with many other substances like alcohols ,strong acids and bases, metals and most inorganics, such as lithium, sodium, iron, lead, arsenic, fluorine, and boric acid. It can be made to bind with mercury but that takes special treatments which you probably won't find in hiking filtration units.

I don't think I'd filter water from streams that are too far downstream from the source because of all the stuff that could accumulate. While I might drink water from the headwaters of the Platte River here in Colorado, I don't thing I'd drink water filtered with a hiking filter from the same river when it dumps into the Missouri in Nebraska. Too much icky stuff has been put into it by then and the water needs more than a small filter to get it out.

The Impossipede

Good tips, thanks. I've always kinda suspected this, but it's good to hear it from someone who knows the science.

Blues Frog

Yhanks. Blues Frog