Evaluation of a Fenton reaction–based fungicide for disinfection of moldy houses in the evacuation zone of the Great East Japan Earthquake: Lab and field tests

Abstract

Houses damaged by the Great East Japan Earthquake that have severe mold problems should be disinfected before or immediately after residents are allowed to return permanently. In this study, the efficacy of a fungicide based on the Fenton reaction was evaluated in lab and field tests. Use of Fenton’s reagent successfully disinfected aqueous solutions containing five species of fungi (Aspergillus niger, Aspergillus penicillioides, Aspergillus restrictus, Cladosporium sphaerospermum, and Wallemia sebi). Spraying Fenton’s reagent solutions (ferrous ions [pH = 3] and hydrogen peroxide [pH = 3]) onto the surface of wood samples inoculated with C. sphaerospermum significantly suppressed fungal growth (mold cover = 12–27%) compared with spraying distilled water (82–97%) or a hydrogen peroxide solution (73–80%). Field tests were performed in two houses in the evacuation area in Fukushima, Japan to evaluate fungicidal activity in a home environment. The airborne fungal counts of C. sphaerospermum, Penicillium, Aspergillus westerdijkiae, Alternaria, Fusarium, Aspergillus versicolor, and Eurotium were strongly decreased by spraying the Fenton’s reagent solutions (except for C. sphaerospermum in House B) (median disinfection rate = 99%). Fungi growing on floor and sink surfaces were inactivated by spraying with Fenton’s reagent solutions (except for Cladosporium spp. in House A and Aspergillus restrictus in House B) (median disinfection rate = 50–98%). Thus, Fenton reaction–based fungicides may be effective for remediation of mold problems in houses.