HNSE-P1-4. The Potential Health Effects of Bacterial Use in Self-Healing Concrete: A Systematic Literature Review

Brandon Polimeni¹
Faculty Mentor: Moses Karakouzian, Ph.D.^2
1College of Sciences, School of Life Sciences
²Howard R. Hughes College of Engineering, Department of Civil and Environmental Engineering and Construction

ABSTRACT
In due course, structures developed from concrete create microcracks exposing it to degradation via the reinforcement steel’s formation of ferric oxide. The aforementioned declines the loading capacity and lessens durability. A corrective technique used to counteract the effects above is bio-mineralization, self-healing the crevices with microorganisms’ metabolic processes. Literature has explored some specific organisms used, and the research strongly supports that the existing bacteria used positively strengthen the concrete’s durability. This literature analysis examines if the selected microorganisms: Sporosarcina pasteurii, Lysinibacillus sphaericus, Bacillus cereus, and Bacillus subtilis used in some current constructional methods will harm the health of consumers or those employees that have potential contact with those elements. Until this point, those strains used in this research appear to be nonpathogenic and safe to use with appropriate biosafety standards. Urease production was of concern due to its virulence factors, but the strains revealed no pathogenic outcomes within this review. After further examination, the concern for human health focused on the biological process that generates ammonium and carbonate via the urease enzyme within these bacteria. During the procedure of self-healing concrete, there is also a concern for ammonium exposure to employees and populations that live near these production sites. Ammonia exposure can cause bronchiolar and alveolar edema, depending on the amount consumed and the duration of human exposure. Sporosarcina pasteurii, Lysinibacillus sphaericus, Bacillus cereus, and Bacillus subtilis exhibit no apparent harm to healthy humans within the analyzed studies.

This research was funded by the Southern Nevada Northern Arizona (SNNA) Louis Stokes Alliance for Minority Participation (LSAMP), which is housed within UNLV’s Center for Academic Enrichment and Outreach and supported by a grant (HRD – 1712523) from the National Science Foundation (NSF). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF.