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Experiments were designed (1) to investigate the bioadhesion, biofilm formation, foxing, and micropitting in documentary collections, (2) to assess the risk of biodeterioration, (3) to investigate the environmental microbial concentration, and (4) to study the influence of environmental factors in biodeterioration of documentary heritage in three archives. The importance of this work in the field of biodeterioration of documentary heritage was verified by bioadhesion and biofilm formation by microorganisms isolated from the collections under study. Bacillus sp. and Scopulariopsis sp. isolated from paper books showed considerable evidence of attacking the paper structure and of pigment production, constituting a hazard to the loss of documentary heritage. Fil: Lavin, Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; Argentina Fil: Gómez de Saravia, Sandra Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; Argentina Fil: Guiamet, Patricia Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; Argentina

The efficacy of ozone biocidal action against planktonic and sessile Pseudomonas fluorescens was studied using different contact times and biocide concentrations. Bacterial biofilms were formed on different metallic substrata frequently used as structural materials in industrial installations. The results showed that the biocidal action of ozone against planktonic cells can be represented by a dose‐response relationship in which the contact time factor was more significant than the concentration. The efficacy of ozone against sessile bacteria was lower than that found for planktonic cells. Turbulent flow significantly improved the inactivation rate, suggesting that a diffusional impediment was involved in the mass transfer process. However, diffusional resistance alone cannot explain the observed decrease in biocidal efficacy. Ozone penetration into the biofilm appeared to be a function of simultaneous diffusion and a reaction of the biocide in the biofilm matrix; the latter may be the result of microscal...