Southern Maryland Wood Treating
US Army Corps
Post-closure Monitoring Report
Quarter 3, September 2002
Southern Maryland Wood Treating
- Prepared for
- United States Army Corp of Engineers
- Prepared by
- Resource Management Concepts, Inc.
Lexington Park, Maryland 20653
Table of Contents
- List of Figures
- List of Tables
- List of Acronyms
- Purge and Sampling Method
- Monitoring Well Results
- QA/QC Samples
- Groundcover Monitoring Results
- Wetland Areas
- Upland Areas
- Appendix A: Field Sampling Forms
- Appendix B: Wetland/Upland Areas Formal Monitoring Field Forms
- Appendix C: Laboratory Data Reports
- Appendix D: Data Validation Reports
List of Figures
- Post Closure Monitoring Well Locations [PDF, 1 page, 109 kb, PDF info]
- Shallow Groundwater Contours [PDF, 1 page, 168 kb, PDF info]
- Deep Groundwater Contours [PDF, 1 page, 167 kb, PDF info]
- Formal Upland Monitoring Transects [PDF, 114 page, kb, PDF info]
- Formal Stream Monitoring Transects [PDF, 36 page, kb, PDF info]
List of Tables
- Water Level Measurements
- Well Inventory
- Drinking Water MCLs and RBCs for Compounds Reported Above the LDL
- Monitoring Well Results [Appendix C]
- Laboratory Performance Criteria [Appendix D]
- Surrogate Recovery Analysis [Appendix D]
- Laboratory Performance Criteria [Appendix D]
- Surrogate Recovery Analysis [Appendix D]
- Laboratory Performance Criteria [Appendix D]
- Surrogate Recovery Analysis [Appendix D]
List of Acronyms
|LCS||Laboratory Control Standard|
|LDL||Lower Detection Limit|
|MCL||Maximum Contaminant Level|
|MCLG||Maximum Contaminant Level Goal|
|MDE||Maryland Department of the Environment|
|MDL||Method Detection Limit|
|MPE||Measuring Point Elevation|
|MS/MSD||Matrix Spike/Matrix Spike Duplicate|
|MSL||Mean Sea Level|
|PAH||Polynuclear Aromatic Hydrocarbon|
|RBC||Risk Based Concentration|
|redox||Oxidation/Reduction potential to standard calomel electrode|
|%RSD||Percent Relative Standard Difference|
|SAP||Sampling and Analysis Plan|
|SMWT||Southern Maryland Wood Treating Site|
|SOP||Standard Operating Procedure|
|SVOC||Semivolatile Organic Compound|
|TDS||Total Dissolved Solids|
|TDU||Thermal Disorption Unit|
|USACE||United States Army Corps of Engineers|
|USEPA||United States Environmental Protection Agency|
Resource Management Concepts, Inc. (RMC, Inc.) sampled 11 groundwater monitoring wells and monitored the upland and stream areas at the Southern Maryland Wood Treating (SMWT) site located in Hollywood, Maryland, on September 9-13, 2002. This sampling fulfilled the requirements for Post-Closure Monitoring, as authorized under Contract # DACW31-01-C-0018 with the US Army Corps of Engineers (USACE), Baltimore District.
The SMWT site was used for treating wood with creosote and pentachlorophenol (PCP) from 1965 to 1978. IT Corporation (formerly ICF Kaiser Engineers, Inc.) began site remediation activities in the spring of 1998; these remediation activities were completed in December 2000.
Three principal tasks are associated with post-closure monitoring at SMWT:
- 1. Sampling and maintaining the monitoring well network
- Monitoring and maintaining the restored wetland areas
- Monitoring and maintaining the ground cover placed on the former excavation pit areas and site construction activity areas
The purpose of the Post-Closure Monitoring effort is to determine the effectiveness of the site remediation.
This sampling effort included four deep wells (MW20D, MW21D, MW34D, and MW37D) and nine shallow wells (MW13, MW14, MW17R, MW27R, MW32, MW33, MW35, MW36, and MW38). A map of the site depicting the post closure monitoring well network is included as Figure 1.
Purge and Sampling Method
Water levels of all the groundwater monitoring wells were measured between 0600 and 0700 on September 9, 2002, before sampling commenced. Table 1 shows the groundwater elevations; Figure 2 and Figure 3 show the shallow and deep groundwater elevation contours. The shallow and deep-water contour maps were based on the most recent survey map (Flora Surveying, March 27, 2001). The blue dashed lines indicate an approximation of groundwater contours based on interpolation among known control points and interpretation of previously published maps.
Table 1: Water Level Measurements
|Well ID||Depth to Water from MPE* (ft)||Water Elevation (ft above MSL**)|
* MPE: Measuring Point Elevation
** MSL: Mean Sea Level
All wells were purged using a Grundfos 2-inch Redi-Flo submersible pump. As specified in the Post-Closure Monitoring Plan (November 2000), each well was purged under low-flow conditions until a minimum subset of parameters (pH, conductivity, temperature, dissolved oxygen (DO), turbidity, and redox) stabilized to within 10% over three consecutive readings. Purge water was not drummed. Table 2 provides physical well data. Appendix A contains the groundwater monitoring field data collection forms.
During field monitoring for low-flow purging, elevated turbidity readings were encountered in MW20D, 34D, and 35. The work plan requires that the turbidity be stable (10% for 15 minutes) before a sample is collected. If this is not achieved before analyzing the sample, the analytical laboratory will filter it. The laboratory filtered the samples for MW20D, 34D, and 35 since the turbidity of the water in these wells did not stabilize. This observation is noted on the groundwater monitoring field data collection forms. MW14 and MW27R were not sampled because the water levels were detected at the bottom of the screened interval. Sampling water below the screened interval would not have been a representative sample of the aquifer. Monitoring wells MW14 and MW27R's depth-to-water levels were checked daily. MW14 and MW27R's groundwater monitoring field data collection form, located in Appendix A, provides technical data for these wells. The water levels were lower in this round as compared to the June 2002 sampling round.
Groundwater samples were collected from each well and analyzed for semivolatile organic compounds (SVOCs) using US Environmental Protection Agency (USEPA) SW-846 Method 8270C, for polynuclear aromatic hydrocarbons (PAHs) using USEPA SW-846 Method 8310, and for pentachlorophenol (PCP) using USEPA SW-846 Method 8151A. SVOC, PAH and PCP samples were collected in three 1-L amber glass bottles without preservative. All samples were packed on ice in coolers and submitted to Severn Trent Laboratories in Pittsburgh, Pennsylvania, for analysis.
Monitoring Well Results
Of the 13 wells being monitored, only samples from 11 were analyzed using USEPA Methods 8270C, 8310, and 8151A. Samples were not drawn from MW14 and MW27R due to low water levels. The samples for MW17R and MW32 were inadvertently filtered by the laboratory but had no adverse impact on the reported results. Two of the three 1-liter samples taken from the equipment rinsate arrived at the laboratory broken and, therefore, could not be analyzed. The remaining sample was analyzed by USEPA Method 8310 only as per the direction of the USACE, the analysis for USEPA Methods 8270C and 8151A were not analyzed.
Laboratory data reports are included in Appendix C. The MW17R report indicated bis(2-Ethylhexyl)phthalate above the lower detection limit (LDL) of 10 µg/L at a concentration of 20 µg/L. The MW20D report indicated bis(2-Ethylhexyl)phthalate above the LDL of 10 µg/L at a concentration of 15 µg/L. An intralab method blank also detected bis (2-Ethylhexyl) phthalate above the reporting limit at a concentration of 20 µg/L. The analyzing laboratory reports this as a common laboratory contaminant. Because the result is less than five times the reporting limit, all sample results for this compound are reported. The results for any sample associated with this blank that have bis (2-Ethylhexyl) phthalate detected are qualified with a "B."
The compound bis (2-Ethylhexyl) phthalate has been detected in samples from the Southern Maryland Wood Treating site before, as reported in the Post Closure Monitoring Report for June 2002. Results above the reporting limit were detected for MW33 (52 µg/L), MW35 (12 µg/L), as well as an equipment rinsate (25 µg/L). The results for the equipment rinsate, however, were qualified because the associated intralab method blank was also detected above the method detection limit (MDL). The remaining samples did not contain any USEPA Method 8270C, 8310 or 8151A target compounds in concentrations above the LDL, as shown in Appendix C, Table 4 (Laboratory Data Reports).
Several compounds were reported to be below the LDL, but above the method detection limit (MDL). Compounds between the LDL and MDL represent a 99% laboratory confidence level that they are present in the sample. However, the reported concentrations are not as accurate or precise as the concentrations at or above the LDL. Reported concentrations flagged "J" are estimated to have a measurement of error between 80% and 150% of the reported concentration.
Testing for matrix interference samples revealed that all surrogate recoveries were within the limits. Surrogates are pure analytes, which are extremely unlikely to be found in any sample; they are added to a sample aliquot in known amounts before extraction and are measured using the same procedures used to measure other sample components. A surrogate behaves similarly to the target analyte and is most often used with organic analytical procedures. The purpose of a surrogate analyte is to monitor performance with each sample. Matrix interferences are those chemical/or physical interferences that impede the analytical instrumentation in detecting the true value concentration of the target analyte within a sample. One possible source of matrix interference may be contaminants that are co-extracted from the sample and result in a positive or negative bias. The extent of matrix interferences will vary considerably from the sample and result in a positive or negative bias. The extent of matrix interferences will vary considerably from source to source, depending on the nature and diversity of the sample matrix. Samples that experienced matrix interference are reviewed with extra scrutiny to verify their data validity and the possible effects of such interference on target analytes.
Table 2: Well Inventory
|Well ID||Install Date||Total Well Depth (ft bgs)||Screen Length (ft)||Well Diameter (in)||Measuring Point Elevation (ft above MSL)||Ground Surface Elevation (ft above MSL)||Screen Interval (ft bgs)|
Note: Wells MW20D, MW34D, MW21D, and MW37D are screened in the deep aquifer. All are double-cased.
bgs = below ground surface
MPE = measuring point elevation (top of riser)
MSL = mean sea level
For comparison purposes, Table 3 lists the drinking water maximum contaminant levels (MCLs) and risk-based concentrations (RBCs) for compounds reported above LDL in Appendix C.
Table 3: Drinking Water MCLs and RBCs for Compounds Reported Above the LDL
|Chemical (a)||Federal Drinking Water Standards (b) µg/L||USEPA Region 3 Tap Water RBCs (c) µg/L|
|MCL||MCLG||Non-carcinogen||Carcinogen 1x10-6||Carcinogen 1x10-4|
MCLG = Maximum Contaminant Level Goal
MCL = Maximum Contaminant Level
RBC = Risk Based Concentration
— = No value available
(a) Note: chemicals without guidance values are presented in this table.
(b) USEPA (1996a)
(c) USEPA from Region III RBCs May 8, 2002
(d) Note: bis(2Ethylhexyl) phthalate is a common laboratory contaminant
With the exception of bis(2Ethylhexyl)phthalate in MW17R, as noted in Section 3.1, none of the shallow wells had detectable concentrations of USEPA Method 8270C, 8310, or 8151A target compounds above the LDL.
The only deep well with detectable concentrations of USEPA Method 8270C, 8310, or 8151A target compounds above the LDL was MW20D. As noted in Section 3.1, none of the deep wells had contamination. The 2001, March 2002, and June 2002 sampling efforts (Figure 3: Deep Groundwater Contour Map) show a westerly flow direction. Sampling efforts conducted by the IT Corporation in October 2000 and December 2000 also revealed a westerly deep groundwater flow direction. Prior to the installation of MW34D and MW37D, as well as the removal of MW19, historical deep groundwater maps have shown a southeastern flow direction. Compared to historical deep groundwater data, recent studies indicate that deep groundwater flow direction has shifted from southeast to west. However, the lack of adequate data points (deep groundwater monitoring wells) precludes the conclusiveness of the proposed flow direction shift.
Matrix spike/matrix spike duplicate (MS/MSD) quality assurance (QA) samples from MW37D were analyzed for SVOC, PAH, and PCP. In addition, the laboratory ran method blanks and laboratory control standards (LCSs) for SVOC, PAH, and PCP analyses. Three rinse blanks (equipment rinsate blanks) were also collected during the sampling event; however, they were only analyzed for PAH because two of the three 1-liter sample jars were broken in transport, as noted in Section 3.1. The data were validated using a combination of method-specific criteria and the Innovative Approaches to Data Validation for USEPA Region III (June 1995). The data that did not comply with quality control specifications and that directly impacted project data were qualified in accordance with USEPA Region III specifications. Criteria evaluated (where applicable) included holding times, blank analysis, initial calibration, continuing calibration, system monitoring compounds, MS/MSD, LCS, and quantitation verification. Data validation reports are located in Appendix D. Any necessary lab data report qualifiers developed from the validation are presented in Table 4 (Appendix C) in the column labeled "Q."
The quality of SVOC data was considered acceptable. No additional qualifiers were applied.
Many of the continuing calibrations performed on instrument GC7 had a %D outside of the +/- 15%D criteria. No qualifiers were applied. The calibrations are further explained in Appendix D in the PAH Review.
Pentachlorophenol was analyzed using USEPA Method 8151A (Chlorinated Herbicides by Gas Chromatograph). Method 8151A is a capillary gas chromatographic (GC) method for determining certain chlorinated herbicides. Pentachlorophenol is the only analyte determined for this report.
Groundcover Monitoring Results
Formal inspection of the wetland area, concurrent with the monitoring well sampling effort, showed no signs of erosion. All wetland disturbed areas have stabilized. Formal stream monitoring field data collection forms and photos are located in Appendix B.
Specific sampling locations within the disturbed areas were selected based on the best professional judgment of personnel experienced in wetland studies. Undisturbed plots were also selected in the same manner.
Figure 5 shows the wetland areas where sources of contamination were removed. Disturbed areas also include those areas between the source areas where heavy equipment traversed the wetland to reach and remove the contamination.
One-meter square plots were placed in disturbed and representative undisturbed areas. Seven disturbed and three undisturbed plots were selected; each stake has been labeled for identification purposes using the naming convention SMD (Stream Monitoring Disturbed) and SMU (Stream Monitoring Undisturbed). A Global Positioning System (GPS) point of each stake was taken. A Garmin, Inc. (model #GPS ColorTrak 00-12015-000) unit was used for GPS data collection. The relative accuracy of this unit is approximately 100 meters. The values reported may not be sufficiently accurate to locate the field points. Points have been field located using the survey stakes. Permanent photographic points were also established in the field to further document the success of the vegetation in each of the sampling plots and are located in Appendix B (Formal Wetland Monitoring). From the head stake of each transect, an up-slope permanent point was established and photographed during this formal monitoring event.
The goal is to normalize the total herbaceous cover of the restored areas by comparing the disturbed areas to baseline plots or undisturbed areas with similar characteristics, and to determine the overall success of the seeding.
The ongoing monitoring program provides evidence of the success of the herbaceous species, both planted and volunteer, within the restored wetlands. Areal cover was estimated by measuring the area that would be covered by projecting aboveground plant structures (stems and leaves) perpendicularly onto the ground. The monitored area used is a one-meter square plot. Cover measurements were made from a point of view directly above each plot. Within each plot, the pooled coverage of all herbaceous species was estimated and recorded to the nearest five percent. The percent cover and wetland frequency indicator value of each species was recorded.
Research of non-desirable species, such as common reed (Phragmites australis), an invasive weed, and purple loosestrife (Lythrum salicaria), was conducted; invasive species coverage was compared to the coverage of such species present in the reference plot. Invasive species were not detected. Information concerning local noxious (invasive) weeds was obtained from the Maryland Department of Agriculture and the Maryland Native Plant Society. The references can be found at the end of this report.
The overall wetland area has a re-growth of 90%. Haul Road has complete ground cover and the wetland boundaries are almost completely filled. A regulatory goal of 85 percent total herbaceous areal coverage had been set for the monitoring program for the wetland seeding area. The 85 percent goal was based on the coverage of all herbaceous plants existing within the plot. In the undisturbed wetland area, the dominant species were the Virginia chain fern (Woodwardia virginica) and the halberd-leaved tearthumb (Polyginum arifolium). Small seedlings of American beech (Fagus grandifolia) are also present. Different species are found throughout the disturbed areas with no clearly defined dominant species. Tree saplings were found throughout the disturbed area, with the dominant variety being the maple (Acer rubrum). Other saplings found in the disturbed area could not be identified. Very few similarities are found between the undisturbed areas and the disturbed areas, possibly due to the break in the canopy, which can cause more sunlight to reach the ground cover. Numerous deer and possible raccoon tracks are evidence of wildlife.
General health of the wetland area can be assessed through monitoring of the benthic communities. Baseline conditions of the streams' macrofauna prior to any remediation activities were established by the United States Fish and Wildlife Service in 1990 with the publication of Biota Investigation of Freshwater Streams Possibly Affected by Southern Maryland Wood Treating Superfund Site. Per the request of the EPA and the USACE, four (4) sampling points were selected for monitoring stream health post remediation, two at the SMWT site (sites #1 and #2) and two on Morgan Road at the man-made pond (sites #3 and #4). Monitoring activities at these points were to include the following parameters: physical characteristics, invertebrate sampling, fish and amphibian survey, wetland delineation, and general observations. Given the significant county and state drought conditions in 2002, the EPA has concluded that it would not be appropriate to conduct a benthic study at the SMWT site because the benthic life would not recover for at least a year. Even with rain, it would not produce a realistic result. These conditions were verified during a site visit on September 17, 2002 and documented in photographs of the benthic sampling points. Those photographs and sampling forms are located in Appendix B.
The annual formal upland area monitoring began in September 2001. The inspection of the upland areas, concurrent with the monitoring well sampling effort, showed no erosion. The uplands disturbed areas are currently stabilized with grass, and the overall upland area is showing 95 percent total herbaceous coverage. Formal upland monitoring field data collection forms and photos are located in Appendix B.
Upland monitoring and reporting is conducted at the same frequency and duration as wetland mitigation monitoring. A regulatory goal of 85 percent total herbaceous areal coverage has been set for the monitoring program for the upland seeding area. The 85 percent goal is based on the coverage of all herbaceous plants existing within the plot.
Figure 4 shows the upland areas where transect stakes were positioned. Transects were created across the disturbed upland areas of the site. Transects bisect Pit 1, Pit 2, Pit 3, Pit 4, Pit 5, and the decon/Thermal Disorption Unit (TDU) areas. One-meter square plots were staked at 100-foot intervals along each transect. This yielded 22 plots for the entire site. Percent areal coverage of all herbaceous species was visually quantified from each plot; each stake has been labeled for identification purposes using the naming convention (e.g., Transect A1, A2, A3).
The intent for selection of transect alignment was to get overall coverage through a significant portion of remedial work areas. The selection resulted in the following four transects:
- Transect A consists of plots A1 through A6. Plot A1 is located near MW38 and the remaining five plots continue north toward MW20D and MW17R, transecting Pit 4, Pit 5, and the former pole barn area.
- Transect B consists of plots B1 through B8. Plots B1, B2, and B3 are located in Pit 1 and continue northeast just south of the access road. Plots B4 through B8 continue northeast, intersecting Pit 2 and the former treated soil area.
- Transect C consists of plots C1 through C8. Plots C1 and C2 are positioned just southeast of the pathway leading to MW13 and MW21D. Plot C2 stops just short of the access road heading down to the stream area; plots C3 through C8 are positioned north of the access road located in Pit 4 and continue across Pit 5 and the decon/TDU areas.
- Transect D consists of plots D1 and D2. Plot D1 is located in the Pit 2 area and plot D2 is located in Pit 3 near MW33.
A Global Position System (GPS) point at each stake was taken. One-meter square plots were placed to provide aerial coverage over Pits 1, 2, 3, 4, 5, and decon/TDU areas. Areal cover was estimated by measuring the area that would be covered by projecting above ground plant structures (stems and leaves) perpendicularly onto the ground. The monitored area used is a one-meter square plot. Cover measurements were made from a point of view directly above each plot. Within each plot, the pooled coverage of all herbaceous species was estimated and recorded to the nearest five percent. The percent cover of each species was recorded.
Permanent photographic points were also established in the field to further document the success of the vegetation in each of the sampling plots and are also located in Appendix B (Upland Formal Monitoring). From the head stake of each transect, an up-slope permanent point was established and photographed during this annual monitoring event and will be used annually thereafter.
Invasive species were not detected. This information is noted on each log sheet.
The overall herbaceous coverage of the upland area is very dense and is dominated by rye (Secale Cereale) species. No invasive weeds were found within the selected reference plots. Both animal (e.g., deer, turtle, squirrel, and rabbit) and plant species are thriving in the upland area.
The regulatory goal of 85 percent total herbaceous area coverage has been met or exceeded in all sampled locations. Informal visual observations indicate the unsampled disturbed areas have reached and exceeded the goal.
Knobel, Edward. Field Guide to the Grasses, Sedges and Rushes of the United States. Rev. ed. Mildred E. Faust. New York: Dover Publications, Inc., 1980.
McKenny, Margaret and Roger Tory Peterson. A Field Guide to Wildflowers of Northeastern and Northcentral North America. Boston: Houghton Mifflin Company, 1968.
Taylor, Norman. A Guide to the Wild Flowers: East of the Mississippi and North of Virginia. Cleveland, OH: The World Publishing Company, 1928.
United States Department of Agriculture. Natural Resources Conservation Service. Plants Database. November 2001. http://plants.usda.gov/java/.
United States Fish and Wildlife Service. Biota Investigation of Freshwater Streams Possibly Affected by Southern Maryland Wood Treating Superfund Site, 1995.