A preliminary investigation of arsenic concentration on surfaces of CCA-treated wood planks in a park

Wood preservatives can protect wood from dry rot, fungi, mold and insect damage, and chromated copper arsenate (CCA) has been used as an inorganic preservative for many years. A portable XRF analyser was used to investigate As... [ view full abstract ]

Wood preservatives can protect wood from dry rot, fungi, mold and insect damage, and chromated copper arsenate (CCA) has been used as an inorganic preservative for many years. A portable XRF analyser was used to investigate As concentration on surfaces of in-service CCA-treated wood planks in a popular park, as well as the influencing field factors of age in-service, immersion and human footfall. With a total of 1207 readings, the observed As concentrations varied from below the detection limit (<10 mg/kg) to 15746 mg/kg with a median of 1160 mg/kg. The oldest planks exhibited high As concentrations, which was related to its original treatment with high retention of CCA preservative. The effect of immersion in the field for about four months was insignificant for As concentration on the surfaces. However, a significant reduction of As was observed for immersion combined with human footfall. Human traffic in general caused slightly reduced and more evenly distributed As concentrations on the wood surfaces. The strong variation, slow aging and relatively weak immersion effects found in this study demonstrate that the in-service CCA-treated wood poses potential health risks to the park users, due to easy dermal contact especially when the wood is wet after rainfall. It is suggested that further comprehensive investigations and risk assessments of CCA-treated wood in residential areas in China are needed, and precautionary measures should be considered to reduce the potential risks to residents and visitors, especially children.