“…Although encouraging treatment efficiency has been documented (Gu et al, 1998;Morrison et al, 2001;Su and Puls, 2003), reactions between ZVI and groundwater constituents causing ZVI corrosion and subsequent secondary mineral precipitation contribute to long term performance reduction of ZVI PRBs (Liang et al, 2003;Slater and Binley, 2003;Wilkin et al, 2003;Jin Suk et al, 2009). Carbonate minerals (often precipitated concurrent with iron oxides (Mackenzie et al, 1999;Phillips et al, 2000;Liang et al, 2003)), are known to significantly impact ZVI reactivity and hydraulic efficiency in systems with frequently encountered high carbonate groundwater conditions through surface passivation and pore clogging (Agrawal and Tratnyek, 1996;Phillips et al, 2000;Liang et al, 2003;Slater and Binley, 2003;Wilkin et al, 2003;Jeen et al, 2006;Jeen et al, 2007;Jin Suk et al, 2009). …”