On Friday May 30th, Ms. Fernanda Mokdessi Auada presented an account of the joint salvage effort undertaken by the Nucleus for Conservation of Public Files of São Paulo (APESP) and the Nucleus of Restoration-Conservation Edson Motta, Laboratory del National Service for Industrial Apprenticeship (NUCLEM-SENAI) following the 2010 flooding of São Luiz do Paraitinga, Brazil. Collective gasps went up from the audience as Auada showed photographs of the devastated city. Among the images was the city all but subsumed by the Paraitinga river, and shots of devastating structural damage to the city’s principal church (São Luiz de Tolosa) and its municipal library.
Thousands of documents, over 15 linear meters in total, were immersed in the flood waters for over 20 days. The papers related primarily to the population’s citizenship and legal identity, making it vital for conservators to save the information contained in the wet and moldy files. Despite the grave condition of the documents–and the challenge of having virtually no money or trained support staff–the overall salvage was a success, Ms. Auada said.
The documents arrived for salvage in three allotments. The first two allotments were treated manually, using traditional flood damage salvage procedures. First, the documents were separated and air dried flat on top of absorbent paper. The documents were then individually documented and inventoried during dry cleaning, these steps carried out in a dedicated cleaning area. Documents that could not be separated mechanically after drying were separated while immersed in an aqueous bath. Papers soiled with heavy accretions of dirt and mud were washed to recover legibility. The papers were then mended, flattened and rehoused in paper folders and corrugated polypropylene boxes. Incredibly, 95% of the documents in the first and second allotments were recovered.
The third allotment, from the Public Ministry, proved to be more problematic, calling for radical treatment. These documents arrived at the APESP three months following the flood, after having been stored wet and housed in garbage bags. Upon drying the materials, it was determined that the extensive mold damage would be impossible to treat using traditional methods. Representing a “worst-case” scenario, this allotment of 176 files was submitted to decontamination by gamma irradiation. The moldy documents were packed in corrugated cardboard boxes and sent to the Radiation Technology Centre for Nuclear and Energy Research Institute (CTR-IPEN) at the University of São Paulo. While still within the cardboard storage boxes, the documents were dosed for disinfection (not sterilization) at 11kGy. This was the first time this type of salvage procedure had been carried out in Brazil.
Following irradiation, the papers were separated and dry cleaned using brushes. The dry removal of the mold spores proved easier and faster than the first two non-irradiated allotments, with sheets separating easily. Perhaps most importantly, the biohazard was eliminated, eliminating the need to quarantine the documents during documentation and dry cleaning. Ms. Auada described the costs of the treatment as acceptable, even within the project’s meager budget. The irradiated documents will be monitored for long term effects of the radiation, with polymerization of the cellulose being of primary concern.