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Advisor(s)
Abstract(s)
The chemical and microbiological quality of drinking-water should be considered within overall public health priorities [1]. A poor quality of drinking-water, due to insufficient disinfection or by human contamination, can be a vehicle for transmitting diseases to consumers. Thus, the quality of both raw water (surface water and groundwater) and the drinking-water has a strong impact on the public health. Among the contaminants, nitrates (NO3-) and faecal indicators (such as thermotolerant coliforms, Escherichia coli and enterococci) represents a major concern because these factors have been associated with adverse health outcomes [1,2].
This study analysed contaminants in drinking-water samples (n=361), including surface water and groundwater in the district of Bragança (during the year 2019), according the standardized protocols [3]. We evaluated the relationship of NO3- concentration with microbial drinking-water parameters (heterotrophic plate count-HPC and faecal indicators), as well as, operational parameter used to assess the performance of a water-treatment process (chlorine residuals and pH) [1].
The nitrate concentration (3.38±5.79 mg/L) presented a significant relation with the presence of the fecal contaminant enterococci (p=0.011). There were significant differences (p<0.001) in regards to nitrate concentration between the water samples according to their provenience, such that groundwater presents higher concentration (mean varying from 4.51 to 6.48 mg/mL) than surface water (mean varying from 1.09 to 1.69 mg/mL). The results also showed that, beyond the presence of enterococci, HPC and coliform bacteria was associated with lower levels of residual chlorine (p= 0.008) and pH (p= 0.004), respectively.
The results suggests the relevance of chemical evaluation of drinking-water and the linking to the microbiological contamination and the operational control of water-treatment process.
Acknowledgements: We acknowledge to Unidade Local de Saúde do Nordeste
[1] World Health Organization, in Developing Drinking-Water Quality Regulations and Standards, World Health Organization, Geneva, 2018.
[2] Mary, H. Ward M. H.; Jones, R. R.; Brender, J. D.; Kok, T. M.; Weyer, P. J.; Nolan, B. T.; Villanueva, C. M.; Breda, S. G. Drinking Water Nitrate and Human Health: An Updated Review. International Journal of Environmental Research and Public Health 2018, 15, 1557.
[3] Standard Methods for the Examination of Water and Wastewater. E.W. Rice, R.B. Baird, A.D. Eaton (23 Eds.), Washington DC, American Public Health Association, 2017.
Description
Keywords
Drinking-water Chemical quality chemical contaminants Faecal contaminats
Citation
Afonso, Andrea F. ; Pires, Bruno; Afonso, Eugénia; Teixeira, Cristina; Nogueira, António José M. (2020). Chemical quality of drinking-water in a Northeast Region of Portugal. In Livro de Resumos do Analítica 2020 – 10º Encontro da Divisão de Química Analítica. ISBN 978-989-8124-30-2
Publisher
Sociedade Portuguesa de Química