Geochemical Impacts of ISCO: A Field-Scale Assessment

    In this month’s Peroxygen Talk, Kelly Moore and Michelle Crimi, PhD discuss the long term impacts on groundwater quality due to the introduction of an oxidant into the subsurface.  
    Ms. Moore is a graduate student in the Department of Envrionmental Health at East Tennessee State University.   Dr. Crimi is an assistant professor in the Environmental Health Science and Environmental Science and Policy Programs in the Department of Biology at Clarkson University.  She earned her PhD in Environmental Science and Engineering from the Colorado School of Mines, and has ten years of experience in remediation science and engineering, focusing primarily on in situ chemical oxidation for groundwater remediation and its impacts on human health risk and aquifer quality. 

Please find their article on the Geochemical Impacts of ISCO below.

Goechemical Impact of ISCO.pdf

As an addendum to the article by Moore and Crimi, extension of their conclusions to the in situ application of activated persulfate can be applied to the following results from the field application described below. This data is kindly supplied by Susanne Borchert of CH2M Hill for a site in Virgina. Klozur persulfate was applied in a novel barrier approach as seen in the figure. Klozur persulfat injection points are shown in yellow, and the blue treatment zones each represent two rows of off-set injections.  For reference, the distance between well MW-01-09 to well RD5-MW-01 is 150 feet.



Site layout plan

Metals Data:

	Chromium	(ug/L)
		Months post injection
Well	Pre-Injection Baseline	2	4	7	10	13
MW-01-18	ND	25	5	ND	5.63	ND
MW-01-23	ND	5	ND	ND	--	--
MW-01-24	ND	5	20	18	--	13
MW-01-25	ND	27	36	31	30.9	22
RD5-MW-01	ND	5	ND	ND	--	ND

	Cadmium	(ug/L)
		Months post injection
Well	Pre-Injection Baseline	2	4	7	10	13
MW-01-18	ND	5	ND	ND	ND	ND
MW-01-23	ND	5	ND	ND	--	--
MW-01-24	ND	5	ND	ND	--	ND
MW-01-25	ND	5	ND	ND	ND	ND
RD5-MW-01	ND	5	ND	ND	--	ND

	Mercury	(ug/L)
		Months post injection
Well	Pre-Injection Baseline	2	4	7	10	13
MW-01-18	ND	0.2	--	ND	ND	ND
MW-01-23	ND	0.2	ND	ND	--	--
MW-01-24	ND	0.79	0.675	0.4	--	0.27
MW-01025	ND	0.41	0.312	ND	ND	ND
RD5-MW-01	ND	0.2	ND	ND	--	ND

From the data, it can be seen that in most cases, metal concentrations are seen to increase immediately post application, but reduce in concentrations in subsequent monitoring events.