16S rDNA amplicon sequencing
groundwater metagenome
No industrial activity and no specific geographical location can be disclosed for the four sites studied due to confidentiality reasons. At each site (B, F, G and H), groundwater samples were collected by SITA Remediation Company (Lyon, France) from the monitoring wells drilled in the deep aquifer i.e. between -20 and -30 m depth for the site B, -7 and -12 m for the site F, -7 and -10 m for the site G and -3 and -6 m for the site H.  Genomic DNA (gDNA) was extracted from all groundwater samples according to the experimental protocol described by Dugat-Bony et al. (2011).