Wetlands Restoration at a Small Arms Firing Range – A Case StudyN. Shetty, P.E., K. Durocher, W. Doucette, R. Wyrick, & D. Klinch – ENSR

J.P. Messier – U.S. Coast Guard

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OUTLINE

– Introduction

– Extent of Impacted Soils

– Risk Assessment

– Proposed Remediation Plan

– Wetland Excavation & Restoration

– Post-Restoration Monitoring

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Introduction

– Small arms firing range operation containing14 firing lanes

– Used earthen berm as bullet backstop– Storm sewer line, currently capped, located

upgradient of the backstop conveyed storm water to wetlands

– Craney Island Creek is bound north of the wetlands

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Site Layout – SAFR, USCG, Portsmouth, VA

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Site Assessment

– Site was registered under the VDEQ Voluntary Program– Conducted Site Assessment in 2003 and 2004

• Indicated the presence of lead and copper in forested wetlands and estuarine marsh

• Sediment• Hydric Soil• Surface Water

– Performed ecological risk assessment to establish site-specific cleanup goals

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Site Plan and Sampling Location

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Extent of Impacted Soils

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Extent of Impacted Soils

– Performed wetland survey

– Used XRF to field screen surface soils before collecting laboratory soil samples

– Soil samples collected from forested & marsh wetlands at different depths

– Total lead in soil samples ranged from 12 to 6,300 mg/kg

– Total copper in soil samples ranged from 3 to 710 mg/kg

– Additional soil data collected to perform ecological risk assessment

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Extent of Impacted Soils

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Risk Assessment

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Ecological Risk Assessment – Problem Formulation

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Ecological Risk Assessment – First Tier

– Direct contact screening• Surface water compared to VA WQS• Sediment compared to ER-L and ER-M• Hydric soil compared to ER-L/ER-Ms and Eco-SSLs

– Bioavailability evaluation of sediments/hydric soils• Simultaneously extracted metals and acid volatile sulfide

SEM:AVS

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Ecological Risk Assessment – Lead

– Forested Wetland• Total Lead in Hydric Soil

All > ER-L of 46.7 mg/kg; range 110 – 6,300 mg/kg

• SEM:AVS All > 1; range 1.2 - 405

• Surface Water4:4 > chronic, 2:4 > acute WQS

– Estuarine Marsh• Total Lead in Sediment

All > ER-L of 46.7 mg/kg; range 54 – 1,600 mg/kg

• SEM:AVS2:8 > 1; range 0.04 – 1.9

• Surface WaterLess than chronic WQS

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Ecological Risk Assessment – Copper– Forested Wetland

• Total Copper in Hydric SoilRange 30 – 220 mg/kg16:18 > ER-L of 34 mg/kg;

• SEM:AVS All > 1; range 1.2 - 405

• Surface Water4:4 exceed acute WQS

– Estuarine Marsh• Total Copper in Sediment

Range 20 – 710 mg/kg 3:4 > ER-L of 34 mg/kg & ER-M of 270 mg/kg;

• SEM:AVS2:8 > 1; range 0.04 – 1.9

• Surface WaterExceed acute WQS

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Ecological Risk Assessment – Second Tier

– Development of Site-Specific Cleanup Values• Copper not as toxic and concentrations co-vary with lead – cleanup

for lead protective of copper • Human health standard of 400 mg/kg lead for

unrestricted/residential use• Food chain evaluation in forested wetland

Marsh wren most sensitive species (80 mg/kg)Removal of 400 mg/kg area yielded average exposure < 80 mg/kg

– Consideration given to bioavailability evaluation of sediments/hydric soils• Generally SEM:AVS < 1 in estuarine marsh• Human contact not major issue due to accessibility• Minimal excavation required

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Proposed Remediation Plan

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Remediation Plan

– Remedial Action: Soil excavation and Wetland Restoration

– Remediation Goals: Clean up lead and copper impacted wetlands to VDEQ Tier II SSL Residential/Unrestricted Use• Lead – 400 mg/Kg• Copper – 310 mg/Kg

– Estimated area of lead and copper impacted soils proposed for removal was 3,600 square feet

– Depth of excavation ~6 to 18 inches in forested wetlands and ~6 to 12 inches in marsh

– Estimated volume was 82 cubic yards (cy) of which 12 cy was characteristically hazardous soils for lead

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Proposed Excavation Plan

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Wetland Excavation and Restoration

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Wetland Excavation

– February 2005• Nation Wide Permit # 38 for wetland disturbance• Sediment and erosion control permit from the City of Portsmouth

– June 2005• Stormwater Management Plan and Stormwater Pollution

Prevention Plan approved by Virginia Department of Conservation– July 2005

• Land Disturbance Permit• VDEQ approval of the remediation work plan

– Late July 2005• Removed 22 tons of hazardous soils and 74 tons of non-hazardous

soils

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Wetland Excavation and Restoration Area

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Wetland Excavation

– Excavation of forested wetlands and loading of hazardous soils in to roll-offs

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Confirmation Sampling and Restoration

– Total of 17 confirmation samples collected

– Sampling grid 25’ x 25’ in forested wetlands

– Sampling 50’ along excavation boundary in marsh

– Lead below remedial goal• 2.3 to 206.6 mg/Kg

– Copper below remedial goal• 1.8 to 32.1 mg/Kg

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Wetlands Restoration

– 50 native shrubs • Silky dogwood (Cornus amomum), arrowood

(Viburnum recognitum), elderberry (Sambucus canadensis), & black willow (Salix nigra)

– Woody trees• Tree species included red maple (Acer

rubrum) and Greenash (Fraxinuspennsylvanica)

– Wetland seed mix (25 lbs/acre)

– Marsh grass plugs (Spartina spp) – 1 plug/square foot

– Pit & mound topography

August 2005

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Groundwater Investigation

– Installed two 2-inch diameter PVC shallow monitoring wells (10’ deep)

– Collected groundwater samples for analysis of lead and copper

– Lead and copper were not detected (below VRP Tier II screening levels)

Monitoring Well in Forested Wetland

Monitoring Well in Estuarine Marsh

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Post-Restoration Monitoring

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Post-Restoration Monitoring

– Three years of annual monitoring and reporting per NWP#38 requirements

– First annual monitoring performed in July/August 2006• Visual inspection • Evaluation of survivorship & plant

health• Inspection of invasive species &

treatment (Habitat)– Increase in density of vegetation

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Post-Restoration Monitoring

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Post-Restoration Monitoring

– Additional confirmation sample in marsh collected outside the excavation area in August – September, 2006

– Sediment analyzed for SEM:AVS• SEM:AVS < 1 (0.04) for both samples

– Surface water samples• Dissolved copper and lead not detected

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End Results….

– On December 11, 2006

– Received closure certification from VDEQ

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End Results…. Marsh restored

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Acknowledgement and Thanks

– Ron Holcomb, USCG ISC Portsmouth Environmental Branch Chief

– Captain Thomas Cahill, USCG ISC Portsmouth

– GMC Scott Fisher, Atlantic Area Armory Portsmouth Supervisor

– Dave Hails, Ecological Restoration

– Virginia DEQ VAP Team: Ahmet Bulbulkaya, Patricia McMurray

– ENSR Team: David Cohn, Nicole Cowand, Seth Ryan, Todd Wilson