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Advisor(s)
Abstract(s)
The 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 health
Description
Keywords
E. coli Research Subject Categories::TECHNOLOGY::Bioengineering
Citation
Afonso, 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. Bragança
Publisher
Sociedade Portuguesa de Química