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Khan BI, Jambeck J, Solo-Gabriele HM, Townsend TG, Cai Y: Release of arsenic to the environment from CCA-treated wood. 2. Environ Sci Technol. 2006 Feb 1;40(3):994-9.
Leaching and speciation during disposal.. Wood treated with chromated copper arsenate (CCA) is primarily disposed within construction and demolition (C&D;) debris landfills, with wood monofills and municipal solid waste (MSW) landfills as alternative disposal options. This study evaluated the extent and speciation of arsenic leaching from landfills containing CCA-treated wood. In control lysimeters where untreated wood was used, dimethylarsinic acid (DMAA) represented the major arsenic species. The dominant arsenic species differed in the lysimeters containing CCA-treated wood, with As (V) greatest in the monofill and C&D; lysimeters and As (III) greatest in the MSW lysimeters. In CCA-containing lysimeters, the organoarsenic species monomethylarsonic acid (MMAA) and DMAAwere virtually absent in the monofill lysimeter and observed in the C&D; and MSW lysimeters. Overall arsenic leaching rate varied for the wood monofill (0.69% per meter of water added), C&D; (0.36% per m), and MSW (0.84% per m) lysimeters. Utilizing these rates with annual disposal data, a mathematical model was developed to quantify arsenic leaching from CCA-treated wood disposed to Florida landfills. Model findings showed between 20 and 50 t of arsenic (depending on lysimeter type) had leached prior to 2000 with an expected increase between 350 and 830 t by 2040. Groundwater analysis from 21 Florida C&D; landfills suspected of accepting CCA-treated wood showed that groundwater at 3 landfills was characterized by elevated arsenic concentrations with only 1 showing impacts from the C&D; waste. The slow release of arsenic from disposed treated wood may account for the lack of significant impact to groundwater near most C&D; facilities at this time. However, greater impacts are anticipated in the future given that the maximum releases of arsenic are expected by the year 2100. |
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