Field study to investigate the leaching and dislodgeability of copper, chromium and arsenic residues from CCA-C treated lumber and to evaluate means for reducing environmental contamination and user exposure
This study was carried out to investigate and measure the amounts of copper, chromium and arsenic residues being leached or dislodged from the surfaces of CCA-C pressure treated lumber in outdoor test structures exposed to natural weathering conditions. Pressure treated lumber purchased locally was used to construct a test structure, consisting of various horizontal, vertical and diagonal components, as well as fence sections. These structures were located at the site of Forintek Canada Corp.'s Ottawa laboratory. Various sections or components of these structures were coated with different types of wood finishes, including paint, varnish, stain and sealer, in order to evaluate their effect on reducing leaching and dislodgeability.
A leaching study was done to determine the leachates of didecyldimethylammonium chloride (DDAC) and borates produced from F2 treated, hem-fir lumber, subjected to simulated rainfall. Taking into account a 1:10 reduction factor, to relate leachate results from single packages to lumber storage yards, the results suggest that the amounts of DDAC and borates would be below those toxic to rainbow trout after 30-120 minutes following onset of heavy rain.
Recently, many forest companies, especially those located on the BC coast, have become interested in the possible danger that the runoff from log accumulations (log yards) may pose to the local flora and fauna and, ultimately, to humans. This info note attempts to put together practical information about how harmful runoff from log yards is created, how it can be prevented and give a brief overview of mitigation options. In creating this info note, a literature review was completed and a list of useful documents can be found near the end.
Sodium borate is a leachable preservative and wood treated with it must be protected from continuous exposure to liquid water. This report evaluates the effectiveness of water repellents in minimising the loss of boron during inadvertent exposure to rainfall during transport and storage.
