Month: October 2007

Environmental Chemistry Field Trip – Day 1, part 2

Our next stop was Appolinaris Spring, which seems to be an uncommon thing in Yellowstone National Park: ordinary springwater. No sulfuric acid, no steam, just plain old water that sinks into the ground and then comes back up later. For most of the park’s history, it seems like this used to be a popular place to stop to get a drink of water.

water emerging from small copper pipes
Although the signs around the spring now all suggest that you really shouldn’t drink it, at least not without filtering it first, I’m kind of kicking myself now for not having tasted it. Perhaps I’ll have to go back on my own time and try it.

Our on-site tests showed a pH of 5.9 (slightly acidic: milk is normally around 6.8 or so, Root Beer somewhere around a more acidic 4.0, cola beverages around 3.0, for reference…), relatively low TDS of about 100ppm, coming out of the ground cool (about 7°C, or 43°F), with very little dissolved Oxygen (about 6.0ppm) and faintly carbonated (300ppm CO2). It reportedly didn’t taste too good, but having foolishly missed out on tasting it, I don’t know why.

There were hints that perhaps contamination from surface water – like rain trickling through bison poo – but quite some time ago they sealed the spring up to protect it from that kind of thing. This is the actual spring now:

Appolinaris Spring is a concrete box in the ground with locked metal tops...
Even so, the signs still try to discourage people from drinking the water coming from the pipes that lead out of the spring, which I take to be the park service covering themselves just in case someone claims to get sick from it. (“Hey, we TOLD you not to drink it!”).

Appolinaris: This spring water has been used by visitors since early days of the park. However modern water tests show periodic contamination. Park waters, even though clear and running are subject to pollution by wildlife. As with all untreated water, purify before drinking.
Periodic pollution by wildlife? What the…

The northern end of a south-bound bisonOh, right. Natural bottled-spring-water flavor. Hey, it’s natural, it’s got to be good for you, right?

And to end this post on a complete and totally baffling non-sequitur: the student lounge I’m sitting in right now has a television constantly tuned to some cheesy mass-media channel. Today it’s “E!®”. I overheard something on it just now that made me sit up and take notice: Evidently “Leprechaun” made a profit. Wow.

One never knows what kind of amazing things one might learn at college…

Environmental Chemistry Field Trip – Day 1, part 1

I can think of a number of things to complain about with regards to living where I do. However, it is nice that we live near enough to Yellowstone to day-trip there. In fact, it’s close enough for my local college to take field-trips there – which we did.

Environmental Chemistry spent the weekend there, examining the area, discussing the chemistry of the natural waters and geothermal features, and collecting samples (yes, we had a permit for this…).

We started with a stop by the side of the Madison River to collect a sample of the surface water. Clear, cool (12°C, or about 55°F), mildly basic (pH of about 8.0), and a TDS reading of about 300ppm, which is roughly the same as mildly to moderately hard tapwater, I suppose.

sampling water from the Madison river

The sampling device -seen being hurled over the water here – is kind of interesting – it’s a hollow tube (a bit of plastic pipe) with two spring-loaded balls that slam shut on either end to trap the water inside when you tug on the string. That lets you throw the device out and trigger it when it gets to the precise spot that you want to take a sample from.

We made a brief stop at Beryl Spring afterwards. We didn’t do any sampling here, but we did talk about acid-sulfate water systems. “Reduced” sulfur – as Hydrogen Sulfide gas – comes boiling out from underground along with steam, and ends up being oxidized by oxygen from the air to become sulfate in the end – combining with the water and forming sulfuric acid.

Sulfur-encrusted pipe at Beryl Spring

Of course, it doesn’t go from sulfide to sulfate all at once. There’s a stop along the way as elemental sulfur. The whitish-yellow stuff here is crystals of elemental sulfur. The black stuff you see is…also crystals of elemental sulfur. The difference is just how the atoms of sulfur collect together. The black form is actually a little less stable than the yellow, so it tends to form first, but then slowly convert to the yellow form over time as the sulfur atoms settle into a more stable arrangement. Being a chemistry class, we didn’t really discuss the possible microbial activity that might be involved here. Note the small patch of dark-green there. I suppose this could be a “Green Sulfur Bacteria“, which does something like photosynthesis except that it makes sulfur instead of oxygen in the process. These are normally anaerobic but perhaps the concentration of hydrogen sulfide (H2S) and carbon dioxide gas coming out of the ground right there is enough to crowd out the oxygen. Alternatively, it could just be a heat-loving cyanobacterium or something.

I really wish I wasn’t too poor to buy a good field microscope to go along with the good lab microscope that I am also too poor to buy…

The last two stops of the day – Appolinaris Spring and Narrow Gauge Spring – will be in the next post…