title: Evaluating the potential for environmental pollution from chromated copper arsenate (CCA)-treated wood waste: a new mass balance approach.
abstract: The potential for pollution from arsenic, chromium and copper in chromated copper arsenate (CCA) treated wood waste was assessed using two lysimeter studies. The first utilised lysimeters containing soil and CCA wood waste mulch exposed to natural conditions over a five month period. The second study used the same lysimeter setup in a regulated greenhouse setting with a manual watering regime. Woodchip, soil and leachate samples were evaluated for arsenic, chromium and copper concentrations. Resultant concentration data were used to produce mass balances, an approach thus far unused in such studies. This novel analysis revealed new patterns of mobility and distribution of the elements in the system. The results suggest that CCA wood waste tends to leach on initial exposure to a leachant and during weathering of the wood. When in contact with soil, metal(loid) transport is reduced due to complexation reactions. With higher water application or where the adsorption capacity of the soil is exceeded, the metal(loid)s are transported through the soil column as leachate. Overall, there was an unexplained loss of metal(loid)s from the system that might be attributed to volatilisation of arsenic and plant uptake. This suggests a hitherto unidentified risk to both the environment and human health.
authors.affiliation: Department of Environmental Science and Technology, School of Applied Sciences, Cranfield University, Bedfordshire MK43 0AL, UK. Electronic address: T.Mercer@cranfield.ac.uk.
authors.forename: T G
authors.initials: TG
authors.lastname: Mercer
authors.affiliation: Department of Geography, Environment and Earth Sciences, University of Hull, Cottingham Road, Yorkshire HU6 7RX, UK. Electronic address: L.E.Frostick@hull.ac.uk.
authors.forename: L E
authors.initials: LE
authors.lastname: Frostick
mesh_terms: D001149:Arsenates / Q000633:toxicity*; D004785:Environmental Pollutants / Q000633:toxicity*; D014934:Wood
chemical_list: D001149:Arsenates; D004785:Environmental Pollutants
keywords: CCA-treated wood mulch; Leaching; Mass balance