Transport of microbial tracers in clean and organically contaminated silica sand in laboratory columns compared with their transport in the field

► Organic carbon could lead to an increase in transport of microbial pathogens due to decreased removal. ► In the presence of increased organic carbon the removal of the microbial tracers E. coli and MS2 phage. ► MS2 phage showed a decreased removal in the presence of low concentrations of organic carbon (1% DOC).