Analysis of Remediation Techniques for CadmiumContaminated Soils at 62 Street Dump Tampa, FL By: Rosemary Collins Overview Site Background Information Contaminant Review Past Remediation Techniques and Analysis My Remediation Plan 5.5 acres Undeveloped land N & W Mix of Rural Residential and Comm. Businesses S&E EPA.gov, 2012 62 Street Dump Started operations in 1960’s as borrow pit Became industrial disposal site until 1976 Continued as unauthorized disposal site EPA.gov, 2012 Site Contamination • Added to NPL in 1983 • 48,000 cubic yards of waste • Contamination in debris, soil and groundwater • Arsenic, cadmium, chromium, copper, lead, nickel and PCBs Cadmium •Trace Metal, Cd(II) ion •No essential biological functions •Few toxicological properties •Water-soluble http://meganandtehmeedah.blogspot.com/2013 Sources •Natural: underlying bedrock, transported parent material, and atmospheric deposition •Anthropogenic: fertilizers, pesticides, refined petroleum products, batteries, biosolids and industrial wastes. Background Concentrations • Most often occurs in small quantities • Tampa, FL .008-.015ppm (Chen, 1999) • Zinc Cores: 200-14,000 ppm (ICA) • FDEP TCLs: • Residential: 82 ppm • Industrial: 1700 ppm Negative Effects • High toxicity at low exposures • Direct-contact risk • Eating and drinking contaminated water • Breathing contaminated air • Negatively impact metabolic processes/ kidney disfunction Remediation Started in 1993 http://www.idsenvironment.com/environment/us/slurry_wall/192/produc ts.html • Excavated and treated contaminated soil • Constructed a below-ground wall around the site • Placed 4.5 acre vegetative cap over site Site Update • Cleanup actions ended in 1995 • Deleted from NPL in 1999 • Site inspections and GW monitoring are continued annually • Site’s 3rd five year review completed in 2009 In Situ Remediation • 3 Main Strategies: • Removal: Soil Flushing • Isolation: Below-ground wall and Vegetative Cap • Stabilization: Phytoextraction/ Phytostablization Removal: Soil Flushing US EPA, A citizens guide to in situ soil flushing, 1996. http://infohouse.p2ric.org/ref/07/06188/ Soil Flushing • Use of Citrate Solution Reagent, 90% removal (Wasay, McGill Univers., 2000) • Reduce costs by recycling clean water back to environment • Most efficient at sites with soils • Relatively homogeneous & permeable • Areas with high water table • Contaminant that is water-soluble Negatives: Spreading to GW, estimating the completeness of removal Isolation: Slurry Walls and Cap • Soil, bentonite and water mixture • Low permeability and chemical resistance at a low cost • Conjunction with capping: 95% effectiveness (FRTR) • Vegetative Cap Stabilization: Phytoremediation • Phytoextraction: remove contaminant from soil and accumulate in roots • Phytostabilization: decrease mobility and bioavailability by adsorbing to roots/rhizosphere T. caerulescens/ Alpine Pennycress • Study by Sneller et al. • Cadmium hyperaccumulator • High cadmium uptake and uptake rate due to Cd-specific transport channels in root membrane • Final: Harvest plants and smelt • Relatively Cheap Strategy Comparison Excavation In Situ Pro: almost complete removal Con: expensive, dispersal during transport Pro: inexpensive, on site, almost complete removal/isolation Con: long term, trouble determining completeness Conclusion • Small area, soil type and moderate level of cadmium contamination make 62 Street Dump perfect location for In Situ Remediation • Cost effective in removing cadmium from soil over time • Improve environment by bringing vegetation back to site • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • Agency for Toxic Substances and Disease Registry, Cadmium, CAS number 7440-43-9, Atlanta, GA. http://www.epa.gov/osw/hazard/wastemin/minimize/factshts/cadmium.pdf Chen, M., Ma, L., Harris, W., Hornesby, A., 1999, Background concentrations of trace metals in Florida surface soils: Taxonomic and geographic distribution of total-total and total-recoverable concentrations of selected trace metals, Report #99-7, p.2-15 to 2-17, University of Florida, Gainesville, FL. EnviroTools, Soil, Sediment, Bed, Sludge: Steps to Cleanup, http://www.envirotools.msu.edu/remediation/remedisoilsed.shtml Florida Department of Environmental Protection, 2005, Soil Target Cleanup Levels, Table II, p.49 Federal Remediation Technologies Roundtable. Remediation technology screening matrix and reference guide, version 4.0. Tech: Groundwater, Surface Water, and Leachate. http://www.frtr.gov/ International Cadmium Association, www.cadmium.org , Great Falls, VA Lambert, M., Leven, B.A., Green, R.M., New methods for cleaning up heavy metal in soils and water, Environmental Science Technology Briefs for Citizens, Hazardous Substance Research Centers, Manhattan, KS. Lone, M., He, Z., Stofella, P., Yang, X. 2008. Phytoremediation of heavy metal polluted soils and water: progresses and perspective. Journal of Zhejiang University Science B. p.210-220. Martin, T., Ruby, M., 2004, Review of In Situ remediation technologies for lead, zinc, and cadmium in soil. Remediation. Vol 14, Issue 3, P.35-53 McLean, J., Bledsoe, B., 1992, Behavior of metals in soils, Ground Water Issue, EPA Office of Research and Development, Washington, D.C. Mohrherr, C., Liebens, J., Rao, K., 2008, Environmental assessment of sediments and water in Bayou Grande, Pensacola, Fl., University of West Florida, Pensacola, FL. Mulligan, C.N., Yong, R.N., Gibbs, B.F., 2001. Remediation technologies for metal-contaminated soils and groundwater: an evaluation. Engineering Geology. Vol 60, Issues 1-4, p.193-207 United States Environmental Protection Agency, Updated July 31, 2012, Sixty Second Street Dump, National Priorities List- Florida, Tampa, FL. United States Environmental Protection Agency, August 1997, Technology alternatives for the remediation of soils contaminated with As, Cd, Cr, Hg, and Pb, Engineering Bulletin. Wasay, S.A., Barrington, S., Tokunaga, S. 2001. Organic acids for the in situ remediation of soils polluted by heavy metals: soil flushing in columns. McGill University, Ste-Anne-de-Bellevue, Canada Wuana, R., Okieimen, F., 2011, Heavy metals in contaminated soils: A review of sources, chemistry, risks and best available strategy for remediation, ISRN Ecology, Volume 2011.