Friday, May 05, 2006

Cheap, natural solution to heavy metals in water

Arielle Garrett of Stellys Secondary School, Saanichton, British Columbia has discovered a cheap, natural way to remove heavy metals from water. The following is a summary of her findings:
Sphagnum moss could be used as a cheap, reusable filter for poor families with metal-contaminated water. I used a Scanning Electron Microscope and Energy Dispersion X-Ray spectrometer, to learn where Sphagnum stores the metals it absorbs. Is it possible to remove metals from Sphagnum cristatum after absorption? I tested this by placing Sphagnum in an acid solution after allowing it to absorb copper. To find out if Sphagnum could remove trace amounts of dissolved arsenic I prepared moss-filtered and control solutions for analysis in an Inductively Coupled Plasma-Mass Spectrometer. Finally, I applied it as a filter for contaminated water, using metal-rich water from my family’s well. I found that copper bound itself all over the surfaces of moss cells, and was easy to remove by soaking in a low pH solution. Sphagnum could be reused as a filter if it was dried between uses, and would remain effective. Sphagnum wasn’t very effective at removing arsenic, but it did remove other metals at low concentrations. Sphagnum is very cheap and transportable, and by showing that Sphagnum is reusable, it makes it even more cost effective; a single filter could last for years. For many places in the world, where people can’t afford the water filters they need, Sphagnum could save lives. Also, Sphagnum reusablility means people wouldn’t need to continually harvestit and harm the environment to obtain filters.
Arielle, thanks for this great piece of research. I'm sure the permaculture community will put the information to good use.


Scott A. Meister said...

Wicked...absolutely wicked. Now I need to go find out how simple it is to propagate sphagnum for it being cheap, that's relative and depends on where you are. It tends to be rather expensive here in Tokyo.

Unknown said...

It is truly amazing what the youth of today are able to do with scanning electron microscopes! I'm hoping that I can get in touch with Arielle after her run on Team Canada in the Intel International Science & Engineering Fair is over. I'd love to get a look at the data and spread it further around the permaculture world where it can be put into use. I could think of quite a few places where it would eb useful.

Ian Graham said...

Our eco-village at Caledon Ontario ( has sulphur tainted water in the communal house water supply. could sphagum moss filter that out? How to find out more about this?
Ian in ON

Unknown said...

Hello again, Ian.

The short answer is that I don't know. One way to find out is to try it out and run a test (formal or otherwise). You could try and track down Arielle Garrett (something I've been meaning to do for a long time).

To avoid all that, you could harvest rain water. Water is usually cleanest when not filtered through 20 cm of bacteria and worm droppings. I doubt the local inspectors would agree, but what the don't know, won't hurt them. The key is proper collection and storage. Millions of Australian alimentary canals agree: rain water is perfectly safe for human consumption. Canada needs to play catch-up with regards to this knowledge.

Unknown said...

Whoa. You have absolutely no idea how creepy this was to suddenly come across! It's really nice to know that someone is interested in my work, despite the fact I haven't yet been able to heavily promote it yet. To tell you the truth, much of my data is rather rough, as when I did this work I only had a very basic grasp of chemistry. However, I am planning to pursue it in a much more formal setting soon (as in 2 or 3 years, as I still have another year to university).
The cultivation of Sphagnum for commercial purposes is something I have been meaning to do some work on, as most of the current work focuses on regrowth after peat harvesting.
The effectiveness of Sphagnum on Sulphur would depend on its placement on the Elemental reactivity scale (which I don’t have handy at the moment sorry). But, honesty, in the form I have been using, it is probably not the best thing for anybody who can afford not too to use except as a last resort. The main draw back is that the moss will need to soak in the water you are intending to use for at least an hour. It’s not exactly viable for the ‘attach to the tap and go’ type of filter. And, if you’re willing to spend, you can probably get much better ones on the market in the developed world. That is why I was proposing using it as a relief measure for third world families. It is far from perfect, but it is affordable and will improve the situation somewhat, but it’s not a miracle fix.
If you’re interested in seeing my full report or even more detailed data, give me an email.
Arielle Garrett

Unknown said...

It's an honor to hear from you!

Permaculturists often find themselves working in dire situations which literally are life and death for the people involved (e.g. a self-sponsored aid project in sub-Saharan Africa). Your findings are a sustainable solution to one of many serious problems that might be encountered. In short, it's extremely useful information.

As for your data, I know of one world-renowned permaculturist who has asked me if I could get it. I would love to get my hands on it. Just click on the contact address on the righthand menu.


Drake said...

As far as filtering water in streams or from runoff sources Paul Stammets Author of How Mushrooms Can Help Save the World used bales of Hay inoculated with Oyster Mushrooms. This helped a bacterial problem in a water retention pond below it. Straw bale filter.

Unknown said...

Thanks, Drake! Stamets also included woodchips as well. And I seem to recall that the mushroom species was Stropharia rugosa annulata, but I'll look it up when I get home and have access to my library (being on a job site now). In the case in the book, Paul was trying to meet EPA standards for E. coli off of his cattle yard. The dense hyphae of the Stropharia worked and he cut his E. coli down to below the limit required.