A Integrated Studies of the Dynamics of Arsenic Release and Exposure From CCA-Treated

Public health concern has increased greatly in the past few years regarding arsenic (As) exposure from direct and indirect contact with CCA lumber due to the realization that As is a far more potent human carcinogen than previously extrapolated from laboratory animal studies. Various national field survey and laboratory studies currently in progress at the Environmental Quality Institute (EQI) do not find a statistically significant relationship between CCA lumber service age and As dislodgement after the first few months of use. Various treatments reduce As dislodgement; however, the effectiveness of water sealants or water-proofing materials appear to last for only about six months, while stains and paints exhibit As-reduction properties through about two years of outdoor exposure. Clearly, there is a need for CCA lumber treatments which will contain As within the wood for much longer time periods. Several candidate materials are currently under investigation at the EQI using an outdoor accelerated aging set-up involving mirror-intensified sunlight and heat, frequent simulated rainfall and intensive foot traffic. Based on preliminary experimental results and extensive direct observation, we believe that the most effective treatments must include both a penetrant/water repellent material as well as a surface crack sealant