Occurrence of Cryptosporidium and Giardia in raw and finished drinking water in north-eastern Spain

Ramo, A. (Universidad de Zaragoza) ; Del Cacho, E. (Universidad de Zaragoza) ; Sánchez-Acedo, C. (Universidad de Zaragoza) ; Quílez, J. (Universidad de Zaragoza)

Resumen: This paper collects the first large-sample-size study on the presence of Cryptosporidium oocysts and Giardia cysts in drinking water plants at the 20 most populated towns in Aragón (north-eastern Spain). Samples of influent raw water and effluent finished water were collected from each plant during different seasons and processed according to USEPA Method 1623. Cryptosporidium oocysts and Giardia cysts were detected in samples collected from 55% and 70% plants, respectively, with nine plants being positive for both protozoa and only four plants being negative over the study period. Both parasites were identified in the raw water throughout the year, with a lower frequency in autumn and a peak in winter, at a mean concentration of 67 ± 38 oocysts per 100 l and 125 ± 241 cysts per 100 l. The turbidity of raw water was not related to the presence or concentration of (oo)cysts, and the (oo)cyst removal efficiency was not related to the type of water treatment. One or both pathogens were identified in the finished water in 7 out of 11 plants with a conventional treatment process (coagulation, flocculation, sedimentation, filtration, and disinfection processes) compared to 4 out of 9 plants that did not apply one of the pre-chlorination treatment steps. Protozoa were detected in the finished water of positive plants at a mean concentration of 88 ± 55 oocysts per 100 l and 37 ± 41 cysts per 100 l, and most of them excluded propidium iodide so were considered potentially viable. The ubiquity of these parasites in the drinking water sources and the inefficiency of conventional water treatment in reducing/inactivating them may present a serious public health issue in this geographical area.

Idioma: Inglés

DOI: 10.1016/j.scitotenv.2016.12.055

Año: 2017

Publicado en: Science of the Total Environment 580 (2017), 1007-1013
ISSN: 0048-9697

Factor impacto JCR: 4.61 (2017)

Categ. JCR: ENVIRONMENTAL SCIENCES rank: 27 / 241 = 0.112 (2017) - Q1 - T1

Factor impacto SCIMAGO: 1.546 - Environmental Chemistry (Q1) - Waste Management and Disposal (Q1) - Pollution (Q1) - Environmental Engineering (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/B82
Financiación: info:eu-repo/grantAgreement/ES/MINECO/AGL2012-32138

Tipo y forma: Article (PostPrint)

Área (Departamento): Área Sanidad Animal (Dpto. Patología Animal)
Área (Departamento): Área Administrativa (Dpto. Ing.Quím.Tecnol.Med.Amb.)