Presentation on theme: "Phosphate-Based Treatment of Contaminated Land in Jasper County, Missouri Missouri Department of Natural Resources –David E. Mosby, RG"— Presentation transcript:
Phosphate-Based Treatment of Contaminated Land in Jasper County, Missouri Missouri Department of Natural Resources –David E. Mosby, RG –firstname.lastname@example.org –573/751-3356
Two Separate EPA Grants Bioavailability of Lead Contaminated Residential Soil treated using In Situ Phosphate Abandoned or Former Lead/Zinc Mine Reclamation Demonstration
1994 lead exposure study done by the Missouri Department of Health and Senior Services 14% of the children had elevated blood lead 25% of the children near the smelter had elevated blood lead EPA began Lead Strategy - started sampling thousands of homes all over Joplin Residential Soil Background
Lead Contamination in surface soils over 800 ppm in Joplin, MO
EPA ROD on Residential Soils Excavate soil above 800 ppm Pb Replace garden soils above 500 ppm Pb Provide loaner HEPA Vacs Soil Repository covering mill waste Long-term Health Education and blood-Pb screening Phosphate treatment above 500 ppm Pb, if proven effective.
5 Pb 2+ + 3 H 2 PO 4 - + Cl - ----> Pb 5 (PO 4 ) 3 Cl + 6H + log K = -25.05 PHOSPHATE TREATMENT Working Hypothesis Addition of phosphoric acid to Pb contaminated Joplin soil will result in formation of chloropyromorphite and reduce the Pb bioavailability and solubility.
Bioavailability Testing Using Immature Swine Pigs fed soil + feed by hand after fasting 15 pigs dosed per soil at 3 different dose ranges Pigs dosed for 15 days 12 Blood Pb at various times + femur, kidney, liver samples analyzed per pig Bioavailability value combination of tissues, but heavily weighted toward blood-Pb
Study Design I. A. Soil Characterization and Bench Treatment of Smelter Soils I. B. Dosing of Treated and Untreated Bench Soils to Immature Swine to Determine Bioavailability II. A. Field Treat Soils and Characterize Pb and Distribution II. B. Dosing of Treated and Untreated Field Treated Soils
Study Design cont. III. A. Incubation of Bench Soils III. B. Dosing of Incubated Soils IV. Dosing of Field Soils Over Time to Pigs V. Analyze Plant Tissue in Field Plots Over Time
Plans for Implementation Intend to implement at ~500 residential properties in Jasper County Will apply to properties with soil between 400 - 800 ppm Pb Should take 3-4 days per property Costs estimated between 1/2-1/3 soil removal= $4000-$5000/yard MDNR hopes to implement as part of state match
Former and Abandoned Pb/Zn Mine Demonstration Project
Project Description Jasper County Site Revegetation Using Biosolids Enhanced Wetland Close mine shafts