1. Case Studies Natural Attenuation Assessment at Plattsburgh Air Force Base, New York Shu-Chi Chang, Ph.D., P.E., P.A. Assistant Professor 1 and Division Chief 2 1 Department of Environmental Engineering 2 Division of Occupational Safety and Health, Center for Environmental Protection and Occupational Safety and Health National Chung Hsing University Wednesday, June 06, 2007

2. Outline Bioavailability Case study 1 Case Study 2 Homework assignment will be on line tonight.

3. Bioavailability Assumptions and considerations Microbes are excluded from the smaller microspores of soil and porous media Intrapore diffusion may be retarded due to sorption Only dissolved fraction is available Aging

4. Bioavailability Max flux at part. surface Max diffusive rate Biokinetic control Pore sorption / diffusion control Max Biokinetic rate Flux at particle surface Max Biokinetic rate Max diffusive rate Bulk phase transport control >1 <1 >1 Ramswani A. and Luthy R., 1997, Measuring and modeling physicochemical limitations to bioavailability and biodegradation. In Manual of Environmental Microbiology, Christon et al (Editors) ASM Press, Washington DC, USA.

5. Site description

6. Plattsburgh AFB, New York

9. Electron donors, electron acceptors, by-products

10. Biodegradation rate and transferred electron equivalents

12. Bird-Eye-View of the Site Source

14. Bioavailability estimation

15. Source lifetime Assumption 1. Source pool dim.: 900ftx315ftx1.5ft 2. f oc =0.001, ρ b = 1.7g/cm 3 3. 25% electron transferred to TCE and DCE Results 1. Tracer methods yield the longest lifetime, while Newell the shortest. 2. Order of mag. diff. for BTEX and TCE, two orders of mag diff. for DCE 3. DCE may be a long term problem in source zone since it is easily degraded under anaerobic conditions. 4. No dramatic diff. in source lifetime with or without the consideration of EBCs in source zone. Methods: 1.Tracer methods w/o EBC 2.Tracer methods w/ EBC 3.B&A methods w/o EBC 4.B&A methods w/ EBC 5.Newell Method w/o EBC 6.Newell Method w/ EBC

23. Trend observation

25. Long term monitoring protocol Purpose Monitoring plan Community involvement Institutional control and long term monitoring Well installation Sampling and analysis plan Monitoring period Contingency plan