Public Lab Research note

Coal Ash and Citizen Monitoring

by gretchengehrke | October 09, 2015 21:48 09 Oct 21:48 | #12287 | #12287

Photo credit: Living on Earth,

As a resident of North Carolina, which has 14 coal-fired power plants and an additional 50 coal ash impoundments, and just last year was home to the third-largest coal ash spill in US history, coal ash is a major concern to me and my whole community.

Earlier this year, Duke Energy (which is the largest utility company in the US) pled guilty to nine criminal violations of the Clean Water Act. As a result of this plea deal, Duke Energy has to do environmental audits of all of its coal-fired power plants, AND, according to this article, Duke Energy is required to log and investigate citizen concerns about coal ash dumps and resultant air and water quality issues. While we will have to wait and see what sorts of investigations will be conducted, on on what timelines, this is an opportunity for community monitoring to be visible.

Coal ash can have serious negative impacts on air and water quality, and of course, human health. Coal ash is a waste product of coal combustion, where most of the carbon has been burned off, and the residual ash is highly concentrated with metals such as arsenic and selenium (which have a whole host of human health impacts, including diseases like arsenicosis). It also has a high silica content, and airborne silica can lead to silicosis (read more about these issues here). Coal ash can be an airborne problem as it is blown from waste piles, and a waterborne problem as it seeps into groundwater from unlined holding ponds, or breaches impoundments directly into surface waters. Groundwater contamination is not visible, so is hard to detect without laboratory testing for metals (except for maybe by the Whee Stat? What are the detection limits with this instrument, @JSummers?). Surface water contamination through seepage also would be difficult to detect by anything other than laboratory metals analysis, BUT, breaches are obvious because of the mobilization of ash into the waterways, and could be documented by photographs. Airborne coal ash may be monitored as general particulate matter, by instruments such as this one in development, led by @mathew.

Who else is interested in coal ash? Let's start a conversation on what we can do to monitor it (or its consequences) in the environment and advocate for better handling of this nasty stuff.


Hi Gretchen, Really interesting project which you should be able to generate some very interesting metals data with the WheeStat. I have been working with potentiostats/voltammeters for many years and although I have not used this particular instrument, there are official EPA methods for Lead and Arsenic by voltammetry (you can also add zinc, cadmium, and copper to the lead scan - arsenic is run seperately) which the WheeStat should be able to analyze in the sub-ppm range. I would also suggest looking into the EPA SW-846 for leachate digestion methods - but using vinegar from the local market should work just as well. If I can be of any help please let me know. WSG

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would a conductivity reading help indicate the presence of metals? I've only ever done bottle sampling with solvents for metals testing.

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Conductivity readings would indicate the presence of ions, but since there is so much calcium, and also substantial amounts of magnesium etc, it would not indicate whether or not trace metals were leaching. That's the tricky part about trace metals -- the ones you are most worried about generally have concentrations at least two orders of magnitude less than other, less harmful metals.

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