Performance comparison of three methods for detection of Giardia spp. cysts and Cryptosporidium spp. oocysts in drinking-water treatment sludge

Autor(es)

Giglio, Guilherme Lelis ^[1] ; Sabogal-Paz, Lyda Patricia ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sao Carlos Sch Engn, Dept Hydraul & Sanitat, 400 Trabalhador Sao Carlense Ave, BR-13566590 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ENVIRONMENTAL MONITORING AND ASSESSMENT; v. 190, n. 11 NOV 2018.
• Citações Web of Science: 0

Resumo

Detecting pathogenic protozoa in drinking-water treatment sludge is a challenge as existing methods are complex, and unfortunately, there are no specific technical standards to follow. Selecting an efficient analytical method is imperative in developing countries, such as Brazil, in order to evaluate the risk of parasite infection. In this context, three methods to detect Giardia spp. cysts and Cryptosporidium spp. oocysts were tested in sludge generated when water with protozoa and high turbidity was treated. Jar testing was carried out using polyaluminium chloride as a coagulant to generate the residue to be analyzed. The results showed that calcium carbonate flocculation with reduced centrifugation and immunomagnetic separation obtained the highest recoveries in the tested matrix showing 60.2%+/- 26.2 for oocysts and 46.1%+/- 5 for cysts. The other two methods, the first using the ICN 7x cleaning solution and the second considering the acidification of the sample, both followed by the immunomagnetic separation step, also presented high recoveries showing 41.2%+/- 43.3 and 37.9%+/- 52.9 for oocysts and 11.5%+/- 85.5 and 26%+/- 16.3 for cysts, respectively. Evidently, these methods and others should be studied in order to make it possible to detect protozoa in settled residue. (AU)

• Processo FAPESP: 12/50522-0 - Contaminação ambiental pelos protozoários Giardia spp. e Cryptosporidium spp. e por Ascaris suum: desafios de detecção, remoção e inativação das formas infectantes
• Beneficiário: Regina Maura Bueno Franco
• Modalidade de apoio: Auxílio à Pesquisa - Temático