Zero-Valent Iron Filtration Reduces Microbial Contaminants in Irrigation Water and Transfer to Raw Agricultural Commodities.

Groundwater depletion is a critical agricultural irrigation issue, which can be mitigated by supplementation with water of higher microbiological risk, including surface and reclaimed waters, to support irrigation needs in the United States. Zero-valent iron (ZVI) filtration may be an affordable and effective treatment for reducing pathogen contamination during crop irrigation. This study was performed to determine the effects of ZVI filtration on the removal and persistence of , and pepper mild mottle virus (PMMoV) in irrigation water. Water was inoculated with TVS 353, filtered through a ZVI filtration unit, and used to irrigate cucurbit and cruciferous crops. Water ( = 168), leaf ( = 40), and soil ( = 24) samples were collected, the were enumerated, and die-off intervals were calculated for bacteria in irrigation water. Variable reduction of PMMoV was observed, however levels were consistently and significantly ( < 0.05) reduced in the filtered (9.59 lnMPN/mL), compared to unfiltered (13.13 lnMPN/mL) water. The die-off intervals of the remaining bacteria were significantly shorter in the filtered (-1.50 lnMPN/day), as compared to the unfiltered (-0.48 lnMPN/day) water. transfer to crop leaves and soils was significantly reduced ( < 0.05), as expected. The reduction of in irrigation water and its transfer to crops, by ZVI filtration is indicative of its potential to reduce pathogens in produce pre-harvest environments.