Afonso, Andrea Luísa FernandesPires, BrunoGonçalves, CátiaTeixeira, CristinaNogueira, António José M.2023-02-242023-02-242021Afonso, Andrea; Pires, Bruno; Gonçalves, Cátia; Teixeira, Cristina; Nogueira, António José M. (2021). Relevance of iron content for Escherichia coli growth in drinking water. In 7th Portuguese Young Chemists Meeting: Book of Abstracts. Bragança978-989-8124-31-9http://hdl.handle.net/10198/27164The chemical and microbiological quality of drinking-water should be considered within overall public health priorities. The chemical contaminants of drinking-water may have different sources, including agricultural activities (e.g. nitrate), geological origin, and as a result of corrosion reactions in the distribution systems (e.g. heavy metals) [1]. In public water system of drinking water, the presence of iron (Fe) could be related to increased bacterial activity including Escherichia coli growth [2,3], an indicator of faecal contamination and the potential presence of pathogenic bacteria, protozoa or viruses [1]. On the other hand, phylogenetically different species of bacteria can promote the oxidation of ferrous iron [Fe(II)] coupled to nitrate (NO3 -) reduction, often referred to as nitrate-dependent iron oxidation [4]. Aim: This research evaluated the relation between the iron (μg/L) and nitrate (mg/L) concentration and the E. coli colony-forming units (CFUs) persistence in drinking water distribution systems. Methods: The samples of drinking water (n=464) were analyzed according the standardized protocols [5]. The proportion of samples with high number of E.coli CFUs (>80) were estimated according to the concentration of iron (<50 or >=50 μg/L) and nitrates (<1 or >=1 mg/L). By including only positive samples for E.coli (n=22), we estimated the Spearman’s correlation coefficients (rs) and the respective p-value (p < 0.05) between iron concentration, nitrate concentration and number of E. coli CFU. Results: There were higher proportion of >80 E.coli CFUs among samples with high iron concentration (p=0.049) while no significant differences were observed by nitrate concentration (p=0.059). When analyses were restricted to positive samples for E.coli (CFUs > 0) we observed a significant correlation between iron concentration and E. coli CFUs; rs=0.497 (p=0.019), while no correlation was observed between nitrate concentration and E. coli CFUs; rs=0.335 (p=0.126). Conclusion: The results emphasizes the iron role in the E. coli persistence in drinking water of public network, rising some concerns in the field of public healthengE. coliResearch Subject Categories::TECHNOLOGY::Bioengineeringconference object