Pre-ozonation of source water: Assessment of efficacy against Giardia duodenalis cysts and effects on natural organic matter

Autor(es)

Kondo Nakada, Liane Yuri ^[1] ; Bueno Franco, Regina Maura ^[2] ; da Silva Fiuza, Vagner Ricardo ^{[1, 3]} ; dos Santos, Luciana Urbano ^{[1, 4]} ; Branco, Nilson ^[2] ; Guimaraes, Jose Roberto ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Sch Civil Engn Architecture & Urban Design, Dept Sanitat & Environm, Ave Albert Einstein, 951 Cidade Univ, BR-13083852 Campinas, SP - Brazil

^[2] Univ Estadual Campinas, Inst Biol, Dept Anim Biol, Rua Monteiro Lobato 255, BR-13083862 Campinas, SP - Brazil

^[3] Fundacao Univ Fed Mato Grosso Sul, Inst Biosci, Fed Univ Mato Grosso Sul, BR-79070900 Campo Grande, MS - Brazil

^[4] Padre Anchieta Univ Ctr, Rua Born Jesus Pirapora Ate 848-849, BR-13207270 Jundiai, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Chemosphere; v. 214, p. 764-770, JAN 2019.
• Citações Web of Science: 2

Resumo

The protozoan Giardia duodenalis is one of the parasites of primary concern in drinking water treatment plants, due to its resistance to chlorination. Another matter of concern regarding chlorination of drinking water is the formation of disinfection by-products in the presence of precursors such as natural organic matter (NOM). In this study, the effects of ozonation (5 mg L-1) on G. duodenalis cysts in raw surface water from a drinking water treatment plant were evaluated, and the presence and alteration of NOM were assessed, as an indicative of the potential to prevent total organic halogen (TOX) formation during post-chlorination. Following ozone treatment, the presence of damaged cysts was observed by direct immunofluorescence assay (IFA) and confirmed by the molecular approach propidium monoazidepolymerase chain reaction (PMA-PCR). Using an animal model, analysis of the intestinal tissues revealed that 80% of the animals inoculated with ozonated water were positive for trophozoites. This study shows that analysis of intestinal fragments is imperative to accurately assess animal infection following inoculation of treated cysts. More importantly, considering the low infective dose of Giardia cysts in susceptible hosts, an ozone dosage usually applied in drinking water treatment plants did not completely inactivate G. duodenalis cysts in surface water. Nonetheless, the results suggest that competitive reactions with NOM have occurred, and the applied ozone dosage has proven useful to remove NOM reactivity, and thus prevent halogenated DBP formation during post-chlorination. (C) 2018 Elsevier Ltd. All rights reserved. (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