Assessing health risks to occupants following remedial insecticidal treatment of timber in dwellings
R J Orsler, E D Suttie, V Rijckaert
Experiments have been carried out to assess (i) the aerial concentrations of volatile wood preservative constituents, and (ii) the potential for contamination from treated surfaces, following in situ insecticidal treatment of timbers in dwellings. Using white spirit as a model for volatile constituents in the treatment of free-standing, wood-lined chambers indicated that temperature and air exchange rate significantly affect the rate of decrease of aerial concentration, but that the rate of diffusion through the treated wood surface may be the ultimate rate-determining step. A simple mathematical model has been proposed to assist in calculating minimum re-entry times after treatment associated with different wood preservative constituents.
Using lindane as a model compound in different solvent formulations, comparison between measurements of the concentration at the surface of the treated wood and pick-up by direct contact has demonstrated the need for an agreed methodology for assessing risk through contamination from treated surfaces. Both methods demonstrated that the amount of lindane close to or at the surface of the treated wood decreased with time, thus reducing potential for pick-up.
Keywords: REMEDIAL TREATMENT; IN-SITU TREATMENT; WHITE SPIRIT; LINDANE; AIR EXCHANGE RATE; TEMPERATURE; MODELLING; AERIAL CONCENTRATION; SKIN CONTACT