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Orientador(es)
Resumo(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
Descrição
Palavras-chave
E. coli Research Subject Categories::TECHNOLOGY::Bioengineering
Contexto Educativo
Citação
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
Editora
Sociedade Portuguesa de Química