Passive Reactive Berm (PRBerm ) to Provide Low Maintenance Lead Containment at Active Small Arms Firing Ranges

Transcription

1 Passive Reactive Berm (PRBerm ) to Provide Low Maintenance Lead Containment at Active Small Arms Firing Ranges W. Andy Martin U.S. Army Corps of Engineers Engineer Research and Development Center Environmental Laboratory (ERDC-EL) May 24, 2007

2 Agenda Introduction SAFR Soil Amendment Studies Static Lysimeters Live Fire Lysimeters Field Demonstration Summary Questions?

3 Introduction Small Arms Firing Range (SAFR) Not all berm materials are the same Geographic locations Soil types Corrosion caused by Bullet Impacts Weather Soil properties ph

4 SAFR Soil Properties Regulatory Issue Non-Issue Regulatory Issue High CEC Small Particle Size High Suspendability Significant Turbidity High Sorption Capacity for Pb (High Kd) High Hydraulic Permeability Extreme Soil Acidity or Alkalinity Natural or Artificial Chelation Low Sorption Capacity for Pb (Low Kd) Surface Water Lead Transport Well Draining Soil Lead Corrodes Slowly Lead Sorbs to Amendment Transport to Groundwater Via Leachate

5 Amphoteric Properties of Metals Metals solubility: Metal complexes Hydroxides Phosphates ph range Metal Complex solubility constants of formations are important (ability to stay as that metal complex)

6 Clean SAFR Soil Sandy Clay Soil SEM / BSED Monitor electron energy from sample to determine the sample composition, e.g. here is a clean sand with trace / background metals content Si SEM Scanning Electron Microscope BSED Backscattered Electron Detector

7 SAFR Soil with Pb Sandy Clay Soil SEM / BSED Si Here is sand with a chunk of lead from a fragmented bullet Pb

8 SAFR Soil with Pb Sandy Clay Soil SEM / BSED Here is sand with a small chunk of Pb from a fragmented bullet Si Pb

9 Generating Berm Sand Homogenizing Berm Sand Amendment Studies Static Lysimeter Sieve Analysis of Berm Sand

10 Amendment Studies Predominant Pb minerals at SAFRs Cerussite (PbCO 3 ) Hydrocerussite (Pb 3 (CO 3 )(OH) 2 Litharge/ Massicot (PbO) Goal of Amendments: Contain metals within SAFR impact area Potential to pass TCLP post range use Mineral Chemical Formula logk 1 sp Lead chloride PbCl Anglesite PbSO Cerussite PbCO Fluoropyromorphite Pb 5 (PO 4 ) 3 F Hydroxypyromorphite Pb 5 (PO 4 ) 3 OH Bromopyromorphite Pb 5 (PO 4 )Br Pyromorphite Pb 5 (PO 4 ) 3 Cl Hindsdalite PbAl 3 (PO 4 )(SO 4 )(OH) Plumbogummite PbAl 3 (PO 4 ) 2 (OH) 5 (H 2 O) Corkite PbFe 3 (PO 4 )(SO 4 )(OH) Solubility product at 25 C (Traina and Laperche, 1999)

11 Fired M-16 rounds into well graded sand Generated ~5000 ppm Pb Conducted sieve analysis Digested Samples Used in column and lysimeter studies Amendment Studies: Berm Sand Generation M16 Bullets Bullet Fragments

12 Amendment Studies: Static Lysimeter Cells 6 Amended Sand Static Lysimeter Cells ~5,000 ppm Pb sand & amendment Control, Buffer Block, SulfiTech A/T, and Apatite II Rain on cells for 16 weeks ~2.94 inches per week Equates to ~47 inches per year Analyzed: Runoff and Leachate water Sand / Amendment samples Soil for Pre and Post TCLP Study Goals: Release ph between 6 to 9 Lead < ppm Copper < ppm TOC < 50 ppm

13 Amendment Studies: Static Lysimeter Study I Results 4 Week Average Leachate Values (green highlighting indicates met study goals, red highlighting indicates that goals not met) Amendment Avg. Lead (mg/l) n=4 Avg. Copper (mg/l) n=4 Filtered Total Filtered Total DOC (mg/l) n=2 ph n=2 Study Goals Control No Amendment < <0.050 < % Mechanical Apatite II % Mechanical Apatite II % Mechanical Apatite II % Buffer Block # < ICP Machine Report Limit of 0.05 mg/l used in calculations for values with <. 2 The average leachate ph for the control soil elevated to 8.21 by the end of 16 rain events.

14 Amendment Studies: Static Lysimeter Study II Results 16 Week Average Leachate Values (green highlighting indicates met objective criteria, red highlighting indicates that goals not met) Average Value (n=16) Amendment Pb (mg/l) Cu (mg/l) Filtered Total Filtered Total DOC (mg/l) ph Study Goals to 9 Control No amendment < <0.022 <0.011 < % Baked Apatite II < <0.021 < % Enzymatic Apatite II % Mechanical Apatite II % SulfiTech A/T <0.018 <0.028 <0.093 < % Buffer Block #5 <0.013 <0.021 <0.020 < ICP Machine Report Limit of 0.01 mg/l used in calculations for values with <. Static Lysimeters do not account for loading of bullets into impact area

15 Amendment Studies: Static Lysimeter Cell Study I Pre and Post TCLP Amendment Pre TCLP Pb (mg/l) Avg (n=3) Post TCLP Pb (mg/l) Avg (n=3) % Reduction [Increase] Un-amended Sand % Baked Apatite II % Enzymatic Apatite II % Mechanical Apatite II % SulfiTech A/T [>99] 5% Buffer Block # TCLP done on whole sample (i.e. no seiving) Initial TCLP did not always reflect final TCLP May work well in lysimeter and column studies, but not well for TCLP Additional TCLP studies planned

16 Amendment Studies: Column vs. Lysimeter Cell Study Saturated Column Soluble Pb / Mass Pb in System (10^6) Berm Sand 5% Mechanical Apatite II 237 5% Enzymatic Apatite II 26 5% Baked Apatite II Intermittent Column Lysimeter Leachate 5% Buffer Block # % Sulfitech A/T Small volume of soil in the column studies did not accurately represent soluble Pb loss in leachate as compared to the lysimeter cells

17 Amendment Studies: Live Fire Lysimeter (LFL) Dynamic Loading Events 150 (5.56mm) rounds per week Over 10 weeks Control and amended sand Potentially worst case scenario for bullet loading Simulated Rain Events 10 L of simulated rain water per week per cell ~1.8 in/week (28.8 in/year) Collected / analyzed leachate Metals TSS ph DOC LFL shooting event

18 Amendment Studies: Live Fire Lysimeter (LFL) Rain Event Bullet Fragment

19 Amendment Studies: Live Fire Lysimeter Study Results 10 Week Average Leachate Values (green highlighting indicates met objective criteria, red highlighting indicates that goals not met) Average Value (n=16) Amendment Pb (mg/l) Cu (mg/l) Filtered Total Filtered Total TSS (mg) ph Study Goals None Set 6 to 9 Control No amendment < < % Buffer Block #5 < <0.080 < TRAPPS 1 <0.050 <0.053 <0.050 < TRAPPS 2 <0.050 <0.058 <0.050 < ICP Machine Report Limit of 0.05 mg/l used in calculations for values with <. Firing into soil changes things Buffer Block #5 did not work as well in dynamic LFL testing DOC averaged < 50 ppm for all but last two rain events

20 Amendment Studies: Live Fire Lysimeter Study Results Total Pb (mg) y = 0.205x R 2 = Leachate 20 Linear (Leachate) Measured TSS (mg) per 0.2 L sub-sample More TSS therefore higher total metals, similar results with static lysimeter study

21 Amendment Studies: Summary Amendment Un-amended Sand Post Static Lysimeter TCLP vs. TCLP Std (5ppm) Post LFL TCLP vs. TCLP Std (5 ppm) Static Lysimeter Avg Total Pb vs. Goal (0.150 ppm) 5% Baked Apatite II n.d. n.d. 5% Enzymatic Apatite II n.d. n.d. 5% Buffer Block #5 5% TRAPPS 1 5% TRAPPS 2 n.d. n.d. n.d. n.d. n.d. n.d. Avg LFL Total Pb vs. Goal (0.150 ppm) 5% Mechanical Apatite II n.d. 5% SulfiTech A/T n.d. TCLP analysis using seived fractions of berm material Additional Live Fire Lysimeter (LFL) Studies

22 Field Demonstration Charleston AFB, S.C. Active Range More than 100,000 rounds per year Fire M-249 (5.56mm) and M240B (7.62mm) from three fixed positions Annual rainfall ~51inches per year, similar to that used in lysimeter studies Field demonstration this summer M-60 range at Charleston AFB, S.C.

23 Field Demonstration Large Scale LFL for use at Active Range

24 Summary Not necessary at all ranges Properly applied Well graded sand and proper amendment results in immobilized metals Improved range sustainment operations Field demonstration (proof of concept) will be conducted at Charleston AFB, S.C. over the next months

25 Questions?