Is there any interest in monitoring DFW’s water supplies for heavy metals, bacteria, and estrogenizing chemicals? I once googled the meaning of my last name and was told that it means “caretaker of the well” so this project would have some silly sentimental value for me. Makers could either drop off water samples or test their water themselves after maybe 40 mins of training for sample prep and 20-30 mins of training on the Raman spectrometer. I’m guessing less than $100 could fund hundreds of samples for heavy metal analysis and I’m unsure about how much the other stuff might cost to prep for analysis.
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Actually I was wondering just the other day how much chlorine was in my water so…yes, there’s interest.
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As a person who works in drinking water regulatory compliance, can I just put out the disclaimer that there are standard methods that should be used to evaluate drinking water quality to get accurate, reliable results. Disinfectant (chlorine or chloramine) levels, in particular, should be tested in the field rather than collecting a sample and waiting long periods to take it to a lab and test it. And I’ve never heard of a spectroscopy type method to test for bacteriological quality. In drinking water, coliform bacteria is tested for as an indicator of possible pathogens in the water. Would this allow you to identify the absence or presence of coliform bacteria specifically?
I don’t mean to discourage learning about the topic, really I’d love to talk about water quality standards, treatment technologies, and all things water with anyone interested, but I’d hate for someone to get misleading results if maybe proper sample collection/preservation/analysis procedures aren’t followed.
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I think it would just detect what’s in the water with the given spectra. But yes I’m really interested in water purification methods. Do you know where I could find more info about it?
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Hey Merissa, good post. Good science is achieved by demanding to see the evidence and reasoning put forth behind claims. Nullius in verba. Also, it’s a lot easier to gain knowledge from an expert than digging through esoteric publications. Will you explain why water should be tested in the field for chlorine and chloramine? I’ll venture a guess that it evaporates out of the sample during transport before testing -hope this isn’t a dumb guess. Are there types of containers made specifically for transporting water for analysis - still, point taken that best analysis is done in the field? Maybe this first or the second Raman build can be made to be transported to areas of suspected contamination. I put this post out there as a feeler for interest and am not claiming to be an expert in water analysis, but if enough interest exists I’ll gladly learn about water testing techniques. I Googled “Raman of Coliform bacteria”, skimmed the highlights, and I feel 99% confident that Raman can be used to identify coliform bacteria,though in this case I’d be very surprised to learn that it’s a simple as shining a laser on the sample. I’d hate for somebody to get misleading results too, but I’d hate even more for DMS members only option to be taking someone’s word.
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Is a Raman spectrometer portable? We could possibly do a brief theory & lab demo session at DMS followed right away by a “field trip” to McInnish Park in Carrollton which is nearby with access to the Elm Fork of the Trinity River. Then we could compare the results of Raman spectroscopy with that of traditional water evaluation methods.
We might as well do this sooner rather than later; before we know it, all this rain will have dried up. 
That’s exactly right. Chlorine off gasses from the water, so if you have a long hold time you’ll get a lower result than what’s truly in the water when it comes out of your faucet. Public water systems have to maintain a minimum disinfectant residual in their distribution system, so it’s normally tested in the field using a colorimetric method and a DPD reagent. (Here’s an example of a commonly used test kit)
As far as sampling containers, there are some specific kinds to use and preservatives to use depending on what you’re testing for. Like for bacteriological sampling, for standard methods I’m familiar with accepted by the EPA, about 100 mLs of water is collected into a sterile container with sodium thiosulfate to remove the chlorine. The faucet where the sample was collected should also be flamed or swabbed with bleach to make sure it’s sanitary (since you’re assessing whether there’s bacteria in the water and not just growing on the faucet). Samples should then be kept on ice and analyzed within 24 hours.
I totally understand what you’re saying about not having to take someone’s word for something, but drinking water is what I do every day so that’s why I wanted to speak up and offer thoughts. Granted… I’m also really unfamiliar with the raman spectroscopy you’re proposing so take that for what you will 
For surface water quality monitoring, maybe folks would be interested in learning/participating in the Texas Stream Team.
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Oh goodness, there are lots of resources! I guess it depends on if there’s a specific type of treatment you’re interested in… like point of use filters/treatment that people install in their homes or the treatment at municipal water systems. Then at municipal water systems, they may have conventional surface water treatment (sedimentation and filtration) or more innovative treatment like membrane filtration or reverse osmosis. EPA, states, and the American Water Works Association set the standards that water systems have to follow, and there’s a lot of information available through those sources, but there’s a lot more out there. I particularly like these Tech Briefs for general overviews on different drinking water topics. If there’s something specific I can guide you to I will do my best to help
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Ahhh nice! Will definitely look more into it. Do you know much about ocean water purification?
Most definitely Raman spectrometers can be portable if designed for this purpose: http://sciaps.com/portable-raman-spectrometers/
But with portability I’d think there’s almost certainly going to be a trade off with signal. I definitely want to do this experiment though so we’ll see what we can come up with for this first build.
Thanks for speaking up and chiming in! It hadn’t even occurred to me that faucets would need to be treated this way (though I hope I’d be diligent enough in my upcoming research to discover this). But like I said, it’s much easier to learn from an expert than to research.
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Can this machine determine ion concentrations? Specifically, if I knew the Calcium (Ca+2), Magnesium (Mg+2), Bicarbonate (HCO3-1) and Sulfate (SO4-2). Sodium (Na+1), Chloride (Cl-1) and Sulfate (SO4-2) ion levels in ppm, I could adjust the water chemistry to suit the beer I’m trying to make on brew days at DMS.
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Let me look into each of these in a little detail and get back to you in a few to several days. I found this link with a quick Google of “Raman Ca2+”. http://pubs.acs.org/doi/abs/10.1021/jf503602n There might need to be a little analysis prep for some, most, or all of these. Cool application!
Also, I think we will likely be able to discern information about the concentration and state of the hops, wort, yeast (i’m fuzzy in my knowledge of what goes on in the brewing process)… with more advance Raman systems we can do so without disturbing the brew.
Not so much ocean water, but smaller scale desalination of brackish ground and surface water. Reverse osmosis treatment is a common treatment for those. The Texas Water Development Board might be a good source of information to check out.
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Could such an instrument be used to detect a depleted anode from a sample of water from the hot tap?
Can you tell me a little bit more about the application? Metals can be usually be detected by Raman if they’re complexed with some other molecular group. What is the anode made of? What’s the lifetime and usage of the anode?
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Water heaters contain a sacrificial copper anode to protect the tank from corrosion. A common way to detect that it has been used up is a sulfurous odor in the water.
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My guess is the copper anode will be oxidized to some form of copper oxide or copper sulfide/sulfate based on Bill’s comment. All forms of copper oxide or copper sulfide/sulfate have Raman active peaks so just depending on the Raman system specs and concentration of copper whatever I think it’s doable but might require long signal acquisition times (maybe hours).
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