10.1021/es404512a.s001 Nora B. Sutton Nora B. Sutton Mariusz Kalisz Mariusz Kalisz Janusz Krupanek Janusz Krupanek Jan Marek Jan Marek Tim Grotenhuis Tim Grotenhuis Hauke Smidt Hauke Smidt Jasperien de Weert Jasperien de Weert Huub H. M. Rijnaarts Huub H. M. Rijnaarts Pauline van Gaans Pauline van Gaans Thomas Keijzer Thomas Keijzer Geochemical and Microbiological Characteristics during in Situ Chemical Oxidation and in Situ Bioremediation at a Diesel Contaminated Site American Chemical Society 2014 Microbiological Characteristics impact Situ Bioremediation treatment area metal sulfides sequential extraction persulfate application soil samples soil structure Diesel Contaminated SiteWhile baseline levels persulfate injection events chemical oxidation pilot scale treatment alkane degradation capacity bioremediation 3 months groundwater characteristics alkB gene gene copy numbers 225 day experiment Situ Chemical Oxidation groundwater parameters Molecular analysis 2014-02-18 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Geochemical_and_Microbiological_Characteristics_during_in_Situ_Chemical_Oxidation_and_in_Situ_Bioremediation_at_a_Diesel_Contaminated_Site/2322208 While in situ chemical oxidation with persulfate has seen wide commercial application, investigations into the impacts on groundwater characteristics, microbial communities and soil structure are limited. To better understand the interactions of persulfate with the subsurface and to determine the compatibility with further bioremediation, a pilot scale treatment at a diesel-contaminated location was performed consisting of two persulfate injection events followed by a single nutrient amendment. Groundwater parameters measured throughout the 225 day experiment showed a significant decrease in pH and an increase in dissolved diesel and organic carbon within the treatment area. Molecular analysis of the microbial community size (16S rRNA gene) and alkane degradation capacity (<i>alkB</i> gene) by qPCR indicated a significant, yet temporary impact; while gene copy numbers initially decreased 1–2 orders of magnitude, they returned to baseline levels within 3 months of the first injection for both targets. Analysis of soil samples with sequential extraction showed irreversible oxidation of metal sulfides, thereby changing subsurface mineralogy and potentially mobilizing Fe, Cu, Pb, and Zn. Together, these results give insight into persulfate application in terms of risks and effective coupling with bioremediation.