Facade eluates affect active and total soil microbiome.

The application of biocides in building materials has become a prevalent practice to mitigate the growth of microorganisms such as algae, fungi, and bacteria on the façades. These can leach out from the material and reach the nearby soil environment. This study aimed to characterize the effect of façade eluates generated within different leaching experiments on total and metabolic active soil microbial community composition and functions. Façade eluates were produced by immersion testing DIN EN 16105 and a natural weathering experiment. Afterward, soil microcosms were treated with the respective façade eluate and incubated for 29 days. Subsequently, the active and total soil microbial community compositions were investigated. Fungal internal transcribed spacer region gene and bacterial 16S rRNA gene were sequenced for active (bromodeoxyuridine labeled DNA) microbial community and total community. Façade eluates reduced total bacterial and fungal gene copy numbers. Overall, active bacterial and fungal richness was reduced and altered in community composition in comparison to the total richness and composition, respectively. Façade eluates retrieved of façade samples without biocides did alter the soil microbial communities to the same extent as façade eluates with biocides. Additionally, members of the active microbiome that benefit from the presence of façade eluates and omitted ones could be identified. Our result demonstrated that façade eluates affect active and total soil microbial community composition and function regardless of the leaching procedure and biocides addition.