Release of arsenic to the environment from CCA-treated wood. 2. 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.
Khan
Bernine I
BI
Department of Civil, Architectural, and Environmental Engineering, University of Miami, P.O. Box, 248294, Coral Gables, Florida 33124-0630, USA.
Jambeck
Jenna
J
Solo-Gabriele
Helena M
HM
Townsend
Timothy G
TG
Cai
Yong
Y
D001149:Arsenates / Q000737:chemistry*; D001151:Arsenic / Q000032:analysis / Q000737:chemistry*; D004784:Environmental Monitoring; D008962:Models, Theoretical; D012037:Refuse Disposal; D018570:Risk Assessment; D012989:Soil Pollutants / Q000032:analysis; D012995:Solubility; D014873:Water Pollutants / Q000032:analysis; D014934:Wood
D001149:Arsenates; D012989:Soil Pollutants; D014873:Water Pollutants; C040890:chromated copper arsenate; D001151:Arsenic