Comparing the Efficacy of Chlorine, Chlorine Dioxide, and Ozone in the Inactivation of Cryptosporidium parvum in Water from Parana State, Southern Brazil

Appl Biochem Biotechnol (2008) 151:464473

DOI 10.1007/s12010-008-8214-3

Juliana Tracz Pereira & Adriana Oliveira Costa & Mrcia Benedita de Oliveira Silva & Wagner Schuchard & Silvia Cristina Osaki & Edilene Alcntara de Castro & Rosangela Clara Paulino & Vanete Thomaz Soccol

Received: 13 December 2007 /Accepted: 6 March 2008 /

Published online: 23 May 2008# Humana Press 2008

Abstract In the present work, assays were performed to compare the efficacy of hypochlorous acid, chlorine dioxide, and ozone in the inactivation of Cryptosporidium oocyst in public water supply from Brazilian South conditions. Experiments were carried out in samples containing 2104 oocysts/ml of C. parvum purified from feces of experimentally contaminated calves. An in vitro excystation method was used to evaluate oocysts viability and to determine the inactivation rates of hypochlorous acid at 2 ppm, chlorine dioxide at 1, 2, and 5 ppm, and ozone at the doses of 0.18, 0.24, 0.36, 0.48, and1.44 mg/l. By using hypochlorous acid, the maximum inactivation rate obtained was49.04% after 120 min. Chlorine dioxide at 5 ppm inactivated 90.56% of oocysts after 90 min of contact. Ozone was the most effective product, rendering an inactivation of 100% with the concentration of 24 mg/l. Resistance of Cryptosporidium to the usual disinfectants and the need for more effective water treatments to prevent waterborne diseases in Brazil are discussed in this manuscript.

Keywords Chlorine dioxide . Cryptosporidium parvum . Disinfection methods . Hypochlorous acid . In vitro excystation . Ozone

J. T. Pereira : A. O. Costa : E. A. de Castro : R. C. Paulino : V. T. Soccol (*)

Setor de Cincias Biolgicas, Departamento de Patologia Bsica, Centro Politcnico, Jardim das Amricas, Universidade Federal do Paran, CEP 81531-990 Curitiba, PR, Brazil e-mail: [email protected]

M. B. de Oliveira Silva

Departamento de Cincias Biolgicas, Disciplina de Parasitologia,Universidade Federal do Tringulo Mineiro, Rua Frei Paulino, 30-CEP 38025-180 Uberaba, MG, Brazil

W. Schuchard

Companhia de Saneamento do Paran, SANEPAR, Curitiba, Paran, Brazil

S. C. Osaki

Programa de Ps Graduao em Processos Biotecnolgicos, Universidade Federal do Paran, Curitiba, Paran, Brazil

Comparing the Efficacy of Chlorine, Chlorine Dioxide, and Ozone in the Inactivation of Cryptosporidium parvum in Water from Parana State, Southern Brazil

Appl Biochem Biotechnol (2008) 151:464473 465

Introduction

Among the protozoan that causes waterborne diseases, Cryptosporidium spp....