1. Arsenic Speciation of Runoff from CCA-Treated Decks

2. Motivation Does the profile imply that all As is captured by upper soil layers?

3. Experimental Set-up sandy soil, 2 ft deck gravel rainwater runoff collection vessel Infiltrating rainwater precipitation

4. Avg. As Conc. 0.73 mg/L (CCA-treated deck) 0.002 mg/L (untreated deck) Runoff

5. Soil Below Deck Soil below untreated deck < 1 mg/kg Primary As Species in Soil were As(V) ~ 95% As(III) ~ 5%

6. 0 2 4 6 8 10 12 14 16 18 20 31223284482121142204259269276287294311339346353360 Day As species concentration (ug/L) As(III) As(V) Total As untreated deck, 2 – 3 ug/L Infiltration

7. Summary  As was found in deck runoff at an average of 730 ug/L. Maximum of 8000 ug/L.  As was found in predominantly surface soil layers.  Soil concentrations increase with age of deck.  As was found at elevated levels in waters that infiltrate below 2 feet of sand.