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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Giardia spp. cysts and Cryptosporidium spp. oocysts in drinking water treatment residues: comparison of recovery methods for quantity assessment

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Author(s):
Sammarro Silva, Kamila Jessie [1] ; Sabogal-Paz, Lyda Patricia [1]
Total Authors: 2
Affiliation:
[1] Univ Sao Paulo, Sao Carlos Sch Engn, Dept Hydraul & Sanitat, Sao Paulo - Brazil
Total Affiliations: 1
Document type: Journal article
Source: ENVIRONMENTAL TECHNOLOGY; v. 42, n. 20, p. 3144-3153, SEP 6 2021.
Web of Science Citations: 5
Abstract

Water treatment plant (WTP) residues, e.g. sludge and filter backwash water (FBW), may contain pathogenic microorganisms, as Giardia spp. and Cryptosporidium spp. However, recovering protozoa from such matrices lacks a formal and precise protocol, which is imperative to improve research in their detection, removal and inactivation. The latter includes a deeper challenge as some recovery methods may compromise viability. This study applied different recovery methods for G. muris cysts and C. parvum oocysts spiked into settled sludge and FBW obtained from a bench treatment. Procedures in sludge involved direct centrifugation, alkaline and acid flocculation, including purification by immunomagnetic separation (IMS). FBW samples were tested for membrane filtration (MF) and heated Tween (R) scrapings followed or not by IMS. Propidium iodide (PI) inclusion was used for oocyst viability evaluation prior and after recovery. Results with purified suspensions lead to higher recovery efficiencies (RE) for C. parvum, which was assumed to relate to poor G. muris fluorescence. Analytical quality assessments were carried out with ColorSeed (R) for the methods that stood out for each matrix and the results indicated lower RE than when organisms from purified suspensions were recovered. Ferric sulphate flocculation and MF, both followed by IMS reached 32.25% and 11.00% RE for Giardia spp. and 19.61% and 2.00% for Cryptosporidium spp., respectively. All of the tested methods affected oocyst viability. These results encourage further research to overcome the matrices complexity explained in this paper and increase RE, taking effects in protozoa viability into consideration. (AU)

FAPESP's process: 12/50522-0 - Environmental contamination by protozoa Giardia spp. and Cryptosporidium spp. and Ascaris suum: challenges of detection, removal and inactivation of infective forms
Grantee:Regina Maura Bueno Franco
Support Opportunities: Research Projects - Thematic Grants