Inadvertent exposure to chemical residues in textile conservation - A risk assessment methodology

Abstract

A range of chemical compounds has historically been used on textiles to prevent and cure insect attack. This presents several problems to conservators working with historical textiles today. Documentation of the treatments was seldom done. Several of the used compounds are persistent and can be retained in materials. Furthermore, some of the substances have been classified as carcinogenic, mutagenic or reprotoxic. The residual contamination can present a health risk to people handling the objects. The character of occupations involved in collections care encompass work tasks carried out in close proximity to objects, and extended periods of exposure is likely. The aim of this explorative study was to gather and present information about pesticide residues in museum textiles in Sweden as well as on how the exposure among textile conservators might take place. This thesis adopted a case study methodology to assess contamination in a folk dress collection. The case explored how a pesticide use history for a museum collection can be created by using different methods. Both hazards and exposure were investigated to enable risk assessments. Hazards in the folk dress collection were assessed through a document review and analytical techniques. Occurrence of organic pesticides were analysed in objects, dust and air using gas chromatography/ mass spectrometry (GC/MS), used qualitatively to screen for a large variety of pesticides. Non-invasive and micro-invasive sampling methods were applied. Volatile organic compounds were collected with solid phase microextraction and TenaxTM sorbent tubes. Wipe sampling was conducted to collect particulate matter. The innovative method “TD-vacuuming” was used to sample for volatile, semi-volatile and non-volatile compounds. Presence of inorganic contaminants in objects was assessed using X-ray fluorescence spectroscopy. Quantitative data was collected but the assessment semiquantitative. To assess exposure scenarios and routes of exposure in textile conservation, interviews and a questionnaire were posed to textile conservators, and dust formation was measured with Particles Plus® in a dust exposure experiment. The study found that textile conservators are exposed to hazardous substances in their work and that some work tasks pose elevated exposure risk. Semi-volatile pesticide compounds can spread throughout collection rooms. Contamination varies between objects and can be due to other factors apart from pesticide residues, such as manufacturing processes. Further, failure to perceive hazards can lead to inadvertent exposure to chemical residues. The results from this study indicate that since hazards cannot be fully controlled, the focus of risk management for conservators should be on limiting exposure. There is a need for future studies on long-term exposure to low levels of chemicals and on chronic health effects among conservators.