The Origin of Hexavalent Chromium as a Critical Parameter for Remediation of Contaminated Aquifers

Two different cases of Cr(VI) contaminated ophiolitic aquifers are presented herein. The first is located at Vergina (Northern Greece), where the maximum Cr(VI) concentration measured was 64 μg/L, being one of the highest geogenic concentrations recorded globally in areas with similar geological background. The second case is located at Inofyta (Central Greece), a makeshift industrial area, where the maximum detected Cr(VI) concentration exceeds 10,000 μg/L, indicating clearly anthropogenic activities as the main source. Although for the Vergina aquifer, area-wide institutional measures and in some cases pump and treat systems might be sufficient to ensure a safe water supply for domestic and agricultural use, this is not the case for the contaminated aquifer of Inofyta. There a comprehensive remediation scheme should be properly implemented adopting, however, realistic remediation targets, that should also take into account the geogenic contribution to the high Cr(VI) groundwater concentrations measured.