Residential Exposures to Arsenic and Hexavalent Chromium from CCA Wood

Abstract

Residential Exposures to Arsenic and Hexavalent Chromium from CCA WoodAbstract Number:1551 Ky Gress* and Lena Ma Ky Gress* University of Florida, United States, E-mail Address: [email protected] Search for more papers by this author and Lena Ma University of Florida, United States, E-mail Address: [email protected] Search for more papers by this author AbstractArsenic exposure from wood treated with chromated copper arsenate (CCA) remains a concern due to its presence around homes. These studies explored exposure to arsenic (As) and hexavalent chromium (CrVI) from CCA wood in several settings, including children’s exposure outside apartment buildings, homeowner’s exposure from power-washing CCA decking and animal exposure from living in zoo enclosures made from CCA wood. Children’s exposure to As from 2-story staircases was estimated through determination of bioaccessible soil As and wipe sampling of dislodgeable arsenic (DA) on hand railings, steps and surfaces of objects stored under staircases. Total As concentrations in soil samples ranged from 1.2–66.6 mg/kg. Lifetime average daily doses from ingestion of DA and soil ranged from 8.1 × 10-6 to 3.0 × 10-5 mg/kg/day. In Florida, homeowners typically powerwash CCA wood using bleach solutions, which can oxidize CrIII to CrVI, a known carcinogen. This study evaluated potential exposures to As and Cr(VI) on the wood surface, in rinsate and in nearby soil, finding concentrations of As in rinsate up to 1.6 mg/L. CCA wood is commonly found on farms and in zoos. Captive animals living in enclosures made from CCA wood can be in constant contact with arsenic-contaminated soil. Soil sampling inside animal enclosures at a zoo in Florida found widespread arsenic contamination, with concentrations up to 9 times higher than allowed at industrial sites. This study is ongoing and includes biomonitoring of animals, including endangered species in a captive breeding program.