# North Boeing Field/ Georgetown Steam Plant Site Remedial Investigation/Feasibility Study

Expanded Stormwater Sampling Interim Data Report

Prepared for

Washington State Department of Ecology Toxics Cleanup Program Northwest Regional Office Bellevue, WA

Prepared by

Science Applications International Corporation 18912 North Creek Parkway, Suite 101 Bothell, WA 98011

September 2010LIMITATIONS

SAIC’s investigation was restricted to co llection and analysis of a limited number of environmental samples, visual observations, and field data, in add ition to summarizing available information from previous site documents. Because the current investigation consisted of evaluating a limited supply of information, SAIC may not have identified all potential items of concern. This report is intended to be used in its entirety; taking or using excerpts from this report is discouraged.Expanded Stormwater Sampling Interim Data Report



# Table of Contents
Page

1.0 Introduction .................................................................................................................. ......1 1.1 Site Description ................................................................................................................2 1.2 Project Scope and Study Objectives ................................................................................2 1.3 Document Organization ...................................................................................................3

2.0 Data Collection and Analytical Methods .........................................................................4 2.1 Flow Measurements .........................................................................................................5 2.2 Sample Collection ............................................................................................................5 2.2.1 Filtered Suspended Solids Samples .........................................................................6 2.2.2 Whole Water Samples ..............................................................................................7 2.2.3 Base Flow Samples ..................................................................................................8 2.2.4 Particle Size Fractionation Samples .........................................................................8 2.2.5 Parking Lot Surface Solids Samples ........................................................................8 2.3 Chemical Analysis ...........................................................................................................9 2.3.1 Filtered Suspended Solids Samples .........................................................................9 2.3.2 Whole Water Samples ..............................................................................................9 2.3.3 Particle Size Fractionation Samples .........................................................................9 2.3.4 Surface Solids Samples ..........................................................................................10

3.0 Flow Measurement Results .............................................................................................11 3.1 Flow Measurements and Precipitation ...........................................................................11 3.1.1 Precipitation ...........................................................................................................11 3.1.2 Tide ........................................................................................................................11 3.1.3 Stormwater Flow Records......................................................................................11 3.1.4 Event Summaries ...................................................................................................14

4.0 Chemistry Results ............................................................................................................1 5 4.1 Filtered Suspended Solids Sampling .............................................................................15 4.1.1 Physical Parameters ...............................................................................................15 4.1.2 Chemical Analysis .................................................................................................16 4.2 Whole Water Sampling ..................................................................................................19 4.2.1 Physical Parameters ...............................................................................................19 4.2.2 Chemical Analysis .................................................................................................20 4.3 Particle Size Fractionation .............................................................................................21 4.4 Surface Solids Samples ..................................................................................................21

5.0 Quality Assurance/Quality Control................................................................................23

6.0 Summary ....................................................................................................................... ....24

7.0 References .................................................................................................................... .....25

Appendix A Totalizer Logs Appendix B Monthly Precipitation Summaries Appendix C Laboratory Data Reports Appendix D Data Validation Report

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### Figures
Figure 1. Overview of NBF-GTSP Location Figure 2. NBF Storm Drain Lines Figure 3. Expanded Stormw ater Sampling Locations Figure 4. Parking Lot Surface Solids Sampling Locations Figure 5. Runoff Volume Versus Precipitation Figure 6. Mercury Concentrations in Filtered Suspended Solids Figure 7. Total PCB Concentrations in Filtered Suspended Solids Figure 8. HPAH Concentrations in Filtered Suspended Solids Figure 9. TSS Concentrations in Whol e Water and Filtered Suspended Solids Figure 10. Total PCB Concentrations in W hole Water and Filtered Suspended Solids



### Tables
Table 1. Samples Collected and Issues Enc ountered During Stormwater Sampling Events Table 2. Samples Collected and Issues Enc ountered During Base Flow Sampling Events Table 3. Chemical and Physical An alysis of Filtered Solids Samples Table 4. Summary of Results for Filte red Suspended Solids Samples at MH108 Table 5. Summary of Results for Filte red Suspended Solids Samples at LS431 Table 6. Summary of Results for Filtered Susp ended Solids Samples for Other SD Lines Table 7. Summary of Results for Filtered Suspe nded Solids Samples in the North Lateral SD Line Table 8. Summary of Results fo r Whole Water Samples at MH108 Table 9. Summary of Results fo r Whole Water Samples at LS431 Table 10. Summary of Results for An alysis by Grain Size Fractionation Table 11. Summary of Results for Parking Lot Surface Solids Samples

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# List of Acronyms

μg microgram μm micron 2LAET second lowest apparent effects threshold ARI Analytical Resources, Inc. CSL Cleanup Screening Levels DOC dissolved organic carbon EAP Environmental Assessment Program Ecology Washington State Department of Ecology EOF emergency overflow EPA U.S. Environmental Protection Agency FC freshwater criteria ft/s feet per second
g gram gpm gallons per minute GTSP Georgetown Steam Plant HHO human health for consumption of organisms HPAH high molecular weight polycyclic aromatic hydrocarbon KBFI Seattle Boeing Field-King County International Airport rain gauge KC King County KCIA King County International Airport kg kilogram L liter LAET lowest apparent effects threshold LDW Lower Duwamish Waterway LPAH low molecular weight po lycyclic aromatic hydrocarbon LS lift station m/s meters per second mg milligram MH manhole mL milliliter MLLW mean lower low water mm millimeter MWC marine water criteria NBF North Boeing Field NOAA National Oceanic and A tmospheric Administration PAH polycyclic aromatic hydrocarbon PCB polychlorinated biphenyl pg picogram QAPP Quality Assurance Project Plan RI/FS Remedial Investigation/Feasibility Study SAIC Science Applications International Corporation

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Page iv September 2010 

# List of Acronyms (continued)

SAP sampling and analysis plan SD storm drain SIM Selective Ion Monitoring SMS Sediment Management Standards SOP standard operating procedure SQS Sediment Quality Standard SVOC semi-volatile organic compound TEF toxic equivalency factor TEQ toxic equivalent quotient TOC total organic carbon TSS total suspended solids USEPA U.S. Environmental Protection Agency VOC volatile organic compound WAC Washington Administrative Code WHO World Health OrganizationExpanded Stormwater Sampling Interim Data Report



## 1.0 Introduction

Stormwater discharge from the North Boeing Fiel d-Georgetown Steam Plant (NBF-GTSP) Site is a potential source of contamin ants to Slip 4 on the Lower Duwamish Waterway (LDW). The Washington State Department of Ecology (Ecolo gy) and the U.S. Environmental Protection Agency (USEPA) identified cleanup of contaminated sediment in Slip 4 as a high priority for the LDW Superfund Site. Cleanup of Slip 4 has been delayed because of concerns about the potential recontamination of sedime nts in Slip 4 from releases of contaminants from this site. A Remedial Investigation/Feasibility Study (RI/FS) a nd cleanup of this site is necessary to allow sediment cleanup in Slip 4 to proceed. Because of the long time frame associated with completing the RI/FS, USEPA asked Ecology to i nvestigate options that might allow the cleanup of Slip 4 to proceed.
To facilitate this process, Ecology tasked Scien ce Applications Internati onal Corporation (SAIC) with the collection of stormwater and continuous flow measurements from the storm drain (SD) line upstream of the King County International Airport (KCIA) SD#3/PS44 emergency overflow (EOF) outfall to Slip 4. In September 2009, stormwater sampling systems were installed at two locations on the NBF-GTSP site: a manhole on the downstream side of the King County lift station (LS431), and manhole MH108 on the north lateral SD line. Whole water and f iltered suspended solids samples were collected at both locations during five storm events as part of the preliminary stormwater sampling task. Sampli ng results were documented in a Preliminary Stormwater Sampling Interi m Data Report (SAIC 2010a).
Based on a preliminary conceptual site m odel (SAIC 2010b) and input from Ecology, USEPA, Boeing, the City of Seattle, and King County, additional sampling needs were identified. The original stormwater sampling task was expanded to include an additional five storm events at these two locations, plus sampling at new locations in the north lateral SD line and in each of the other lateral SD lines at NBF. Base flow sampling was also incl uded to assess the contribution of contaminants in base flow to discharges from the KCIA SD#3/PS44 EOF outfall. Additional samples were collected to determine the concen trations of various chemicals of concern in different particle size fracti ons, in support of Slip 4 sedi ment recontamination modeling.
This report includes the chemical analysis resu lts for filtered suspended solids and whole water samples collected at 13 locations during the cour se of the expanded stormwater sampling phase (February through July 2 010). Results from the Preliminary Stormwater Sampling Interim Data Report (SAIC 2010a) are included to present a co mprehensive account of stormwater data collected at NBF-GTSP.
In addition, continuous flow measurements colle cted over the duration of sampling are reported. These measurements will be used in conjunction with the chemistry data to calculate contaminant loadings to Slip 4. These loadings will be reported in a separate technical memorandum. Sampling was conducted following th e study design and methods described in the August 2009 Sampling and Analysis Plan and Quality As surance Project Plan for Preliminary Stormwater and Filtered Suspended Solids Sampling (SAIC 2009a) and the April 2010 Work Plan and SAP/QAPP Addendum Expanded Stormwater Monitoring (SAIC 2010b).

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### 1.1 Site Description

The NBF-GTSP Site is located east of Slip 4 and approximately 4 miles south of downtown Seattle. NBF is located at 7500 East Marginal Way S and occupies approximately 130 acres primarily within the Seattle and Tukwila city lim its (Figure 1). The site is leased by Boeing from King County, with the exception of a few acres on e ither side of the former GTSP flume, which is leased from the City of Seattle, and Buildi ng 3-390 and an adjacent parcel used for parking, which are owned by Boeing. The head of Slip 4 is approximately 150 feet from the northwestern boundary of NBF.
The NBF SD system drains a total area of a pproximately 328 acres; this includes stormwater flow from 171 acres of KCIA, wh ich enters the site from the nor th and east at four locations (SAIC 2009b). Most areas of NBF drai n to one of four lateral SD lines (the north, north-central, south-central, and south lateral SD lines), which are directed to a trunk line that passes through a King County (KC) lift station, under East Marginal Way S, and to the 60-inch KCIA SD#3/PS44 EOF outfall at Slip 4 (Figure 2) . Stormwater from a smaller ar ea near Building 3-380 (which previously discharged to Slip 4 via a separate SD line) and a parking area downstream of the lift station also drain to Slip 4.



### 1.2 Project Scope and Study Objectives

The purpose of the expanded stormwater sampling e ffort was to collect samples of whole water and filtered suspended solids during five stor m events at LS431 and MH108. During three of these events, filtered solids were collected near the downstream end of each lateral SD line and from up to six locations in the north lateral SD line. Filtered solids and whole water were collected from base flow during two time peri ods near the beginning a nd end of the expanded sampling task. Specific objectives for sampling are as follows:

• Obtain a larger data set for whole water a nd filtered solids at LS431 and MH108 to allow for a better determination of the relationship between these two sample types. Continued sample collection at these two locations will allow for a more accurate calculation of contaminant loadings from the north lateral SD line relative to the entire site.

• Conduct base flow sampling at LS431 and MH108 to assess contaminant loadings due to infiltration of groundwater to the SD system.

• Collect filtered solids samples from the north -central SD line, south-central SD line, south SD line, Building 3-380 drainage, a nd parking lot area to assess contaminant contribution (polycyclic aromatic hydro carbons [PAHs], metals, polychlorinated biphenyl [PCBs], dioxins/furans) from areas out side the north lateral SD area, to assess whether PCB source control actions taken in the north lateral SD line are sufficient to reduce the potential for Slip 4 sediment recontamination.

• Collect filtered solids at six locations upgradie nt of MH108 in the north lateral SD line to identify and trace sources of PCBs in the north lateral SD line and allow any needed interim actions to focus on speci fic sub-drainages of concern.

• Determine concentrations of PCB Aroclors, me tals, and PAHs in four different particle size fractions.

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• Compare chemistry results from all SD lines to relevant surface water or sediment criteria.



### 1.3 Document Organization

The primary purpose of this report is to summ arize and evaluate the results of the expanded phase of the NBF-GTSP stormwat er investigation. Results from the preliminary stormwater investigation have been incorpor ated into this document for ov erall comparisons of results. Section 1.0 describes the NBF-GTSP site and document organization. Section 2.0 describes sampling methods that differed from the prelimin ary stormwater investig ation or the SAP/QAPP Addendum (SAIC 2010b). Flow measurement data are summarized in Section 3.0. Analytical results for filtered suspended solids and whole water are pres ented in Section 4.0. Section 5.0 summarizes the data validation reports. A summary of findings is presented in Section 6.0. References are listed in Section 7.0. The appe ndices include totalizer logs, event flow and precipitation summaries, laboratory re sults, and data validation reports.

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## 2.0 Data Collection and Analytical Methods

This section describes the collect ion of flow measurement data and the sampling and analytical methods associated with filtered suspended soli ds, whole water, and base flow samples.
Samples were collected at 13 loca tions described below (Figure 3):

• LS431, located on the discharge (southwest) side of the KC lift station. All four major SD lines plus the Building 3-380 line drain to th e lift station prior to entering Slip 4.

• MH356, located on the southwestern corner of Building 3-369, approximately 45 meters (150 feet) upgradient of the lift station. This location is near the downstream end of the south lateral SD line.

• MH369, located at the north end of the small pa rking lot on the northwest side of Building 3- 390. This location is 210 meters (700 feet) upgradient of the lift station on the south central lateral SD line.

• MH226, located in a flight apr on 58 meters (190 feet) north of MH369. MH226 is on the north central lateral SD line, 107 mete rs (350 feet) upgradien t of the junction with the north lateral SD line.

• MH108, located along the north lateral SD line, north of Building 3-380 and near the corner of Building 3-350. MH108 was selected to repres ent stormwater drainage from the north lateral SD line. MH108 is located 85 meters (275 feet) upstream of the connection between the north and north-central SD lines.

• CB423, located between Building 3-380 and the lift station. Flow through CB423 is representative of the Building 3-380 drainage.

• MH434, located 23 meters (75 feet ) downstream of the lift station. MH434 is representative of flow from a section of parking lot border ing East Marginal Way S and additional parking spaces within NBF. MH434 was the only drainage ar ea sampled that does not drain to the lift station.

• MH133D, on an extension of the north late ral SD line southwest of Building 3-315.

• MH178 and CB173, in the parking lot west of Bu ilding 3-323 and about 23 meters (75 feet) southwest of the GTSP boundary. These locations are the farthest upgradient structures sampled as part of the expanded stormwater sampling program. CB173 drains NBF property. Flow at MH178 enters from off site.

• CB165 is northwest of Building 3-322. This location was adjacent to the March 2010 soil excavation area near Buildings 3-322 and 3-302.

• MH152 and MH138 are southwest of Building 3-626.

Two locations proposed in the SAP/QAPP A ddendum (SAIC 2010b) could not be sampled. Proposed sampling at MH160 was not possible due to insufficient stormwater flow. MH169 is within the fuel test area. Sampling at this lo cation would have required explosion proof sampling equipment. Designing and implementing th is equipment was co st prohibitive.

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There were two other substant ial deviations from the SAP/ QAPP Addendum. Up to 20 grab samples were to have been collected at vari ous locations. Between March and May 2010, Landau collected grab samples at all NBF SD structures , which contained sufficien t material to sample (Landau 2010). Boeing subsequently cleaned out all catch basins in the north lateral SD line. Additional grab sampling locations were not identif ied. In place of the grab samples, six parking lot surface solids samples were collected to address potential data gaps associated with filtered solids collection at MH434.

Tidal inflow was a frequent problem at MH434. All samples collected at MH434 consisted of tidal water co-mingled with stormwater. Filtered solids results may not be representative of the sampled event. Surface solids samples were collected near Drain 283A and Drain 436A, two samples were collected from an area south of Drain 435B, and two samples were collected from an area south of Drain 434A (Figure 4). The surf ace solids samples represent material in the parking lot that is adjacent to the SD trench dr ains and could therefore enter the SD system and be transported to Slip 4.



### 2.1 Flow Measurements

All stormwater flow measurements were collect ed using Teledyne Isco (Isco; Lincoln, NE) equipment leased from Whitney Equipment, Both ell, WA. Clearcreek Contractors performed all confined space entry necessary for the Isco installation at each of these locations.
Sampling equipment at MH108 and LS431 was installed as part of the preliminary stormwater sampling (SAIC 2010a). Continuous flow measurements at LS431 were collected using an Isco 6712 stormwater sampler equipped with a Model 750 area velocity flow module. AC power from the east side of the lift station was available to power the Isco unit. Due to the short cycling time of the lift station pumps, the flow sampler was programmed to collect da ta every 1 minute.

Continuous flow measurements at MH108 were co llected using an Isco Model 4250 flow meter run off a 12-volt marine battery. Th e battery was replaced on a biw eekly basis for the duration of the sampling period. The flow meter was progr ammed to collect data every 15 minutes.

Continuous flow measurements at MH226, MH356, MH369, MH423, and MH434 were collected using Isco Model 2150 flow meters. Each unit was powered by two internal 6-volt lantern batteries. MH356 and MH434 were set to collect data at 1- minute intervals. The unit at MH369 was briefly set to 1-minute intervals, but was switched to 15-minute intervals when the sensor was moved (Section 3.1.3). MH226 and MH423 were set to collect data at 15-minute intervals.



### 2.2 Sample Collection

Expanded stormwater sample collection efforts be gan in February and ended in July 2010. Storm event-based whole water and filtered suspended solids were collected at up to 13 sample locations during a given storm event (Table 1). Base flow samples were collected at LS431 and MH108 (whole water and filtered suspended solid s) and at CB173 (filtered suspended solids) (Table 2).

September 2010 Page 5Interim Data Report Expanded Stormwater Sampling

A total of six storm events were sampled. Whole water and filtered solids were collected during Events 6 through 10. Event 9b involved filte red suspended solids sampling at MH434 and CB423 due to previous sampling difficulties at these locations. LS431 was also sampled during Event 9b to provide a constant lo cation between events. Base flow samples were collected during three time periods. During the first base flow event, whole water was collected at LS431 and whole water and filtered solids we re collected at MH108. Filtered solids were missed at LS431 due to sampling error. Filtered solids were collected at LS431 during a second base flow event, (Base Flow Event 1b in Table 2). A third base flow event was sampled at the completion of expanded stormwater sampling to obtain a whol e water and filtered solids sample at both locations during the same time frame.
Sample equipment for each location was stored in a polypropylene garden shed for protection. When not in operation, the sheds were moved to a nearby storage location to prevent interference with Boeing operations. During samp ling, vehicles were parked in front of the flight line sample units to provide a buffer in the event of jet blasts.
The start and end time for each sampling event are based on the times listed on the totalizer log sheets (Appendix A). These times are listed separately for each lo cation, and may vary slightly between locations depending on when each sample unit was activated.



### 2.2.1 Filtered Susp ended Solids Samples
The collection of filtered suspended solids at the expanded stormwater sampling locations was performed in a manner consistent with prelimin ary filtered suspended solids sample collection methods, as outlined in the preliminary stor mwater sampling SAP/QAPP (SAIC 2009a). Events and locations where filtered suspended solid s were collected are listed in Table 1.
Prior to each sampling event, clean, pre-weighed f ilters were installed in each filter housing and the beginning totalizer readi ng was recorded on the totalizer field form (Appendix A). A 50- gallon per minute (gpm) pump was positioned in the SD beneath the manhole cover. A float switch on the pump was set to trigger sampling when SD water depth exceeded a pre-determined depth. Once triggered, water was pumped up through the intake line and split into parallel filter housings. Each filter housing contained a 20-inch long, 4-inch diameter filter bag. All filter bags were constructed of 5 micron (μm) polypropylene fe lt. The outflow from ea ch filter housing was piped into a totalizer to measure flow. Outflo w from both totalizers was combined and piped back into the SD. When possible, discharge pi pes were installed downstream of the effluent pump, avoiding the potential for re -circulating water. After sampli ng, the final totalizer readings were recorded, filter housings were drained, and filters were removed. Residual water was gently squeezed from the filter bags. Filter samples we re placed in clean, labeled, Ziploc bags and stored on ice for delivery to the analytical laboratory.
Exceptions to this method are described below:
MH133D, MH138, MH178, and MH423. Field observations made during Event 8 indicated that stormwater was not deep enough to trigger continual fl oat switch activation at these locations. The periodic activation of the float sw itch and pump allowed for excess air to enter the system, causing air lock and pr eventing further sampling.

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Prior to Event 9, pre-washed silica sand was tr iple bagged inside polypropylene sand bags and placed slightly downstream of the effluent pump to increase the water depth. All sand bags were tightly secured. During subsequent events, stor mwater flows successfully triggered the float switches and activated sample equipment at all locations except MH178, which required the installation of a second sandbag after Event 9.

CB165. The float switch was inconsistently activat ed during Event 8 due to the small vault volume and low flow of stormwat er. The pump was plugged into an automated timer and set to 15-minute intervals to prevent the pump from ov erheating. Prior to Event 9, the discharge pipe was removed from the system and stormwater wa s allowed to continuously re-circulate during sampling.

CB173. No additional modifications were made to this location. It is important to note that the SD leaving this structure was engineered to be inverted. During a storm, discharge water from the filtration system would flow backwards into the CB173 vault. An unknown quantity of stormwater was likely re-circulated though the sample unit during sampling.

MH434. Stormwater flow during Event 8 inconsistently activated the float switch due to low flows. During Event 9, a high tide obscured the stormwater flow. Prior to Event 9b, a weir was constructed to allow the stormwater to accumulate to a depth that could be sampled. The weir consisted of a 0.15-meter (6-inch) tall piece of wood cut to fit the wi dth of the drain. Ten sandbags were secured and positioned to hold the weir in place.
Several days after Event 9b, field personal notic ed the weir had been dislodged and several sandbags had moved. It is believed a combination of high velocity flow from the lift station and a high tide blocking the flow to Slip 4 resulted in water being diverted toward MH434. Sample results collected at this location may not be re presentative of actual stor mwater runoff from the parking lot. They are likely a mi x of parking lot runoff, tidal wa ter from Slip 4, and stormwater discharged from the lift station.



### 2.2.2 Whole Water Samples
Whole water samples were collected using Isco 6712 stormwater sampling units at MH108 and LS431. The inlet for the Isco samplers and the fl ow sensors were mounted adjacent to each other on stainless steel scissors brackets. As outlined in the preliminary stormwater sampling SAP (SAIC 2009a), the flow sensor and Isco inlet we re installed upstream of the filtered solids effluent pump at MH108. However, the large vault-like drain configuration at the lift station prevented upstream installation of the bracket at LS431. Instead, the flow sensor and inlet were installed about 1.5 meters (5 feet) downstream of the effluent pump. The output from the filtered solids sampler was designed to discharge an ad ditional 0.6 meter (2 feet) farther downstream.
Flow weighted sampling programs were selected for each Isco unit prior to a sampling event. Flow weighting consists of collecting equal vol ume aliquots at predetermined volume intervals. The aliquot volume was constant at 500 milliliters (mL) for all sampled events. The volume interval was calculated using forecasted rainfall totals and the relations hip between rainfall and stormwater flow established from previous rain events.
All samples were collected in 5-gallon glass carboys. During sampling, the carboy and collected water were stored on ice in the base of the Isco unit. After sampling, the carboy was delivered to

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the analytical laboratory, where the sample was split for analysis. The laboratory was responsible for decontamination of the carboy as speci fied in the SAP/QAPP Addendum (SAIC 2010b). Additional information regarding whole water sample events is listed in Table 1.



### 2.2.3 Base Flow Samples

The methods described above for filtered suspended solids and w hole water sampling were also used to collect base flow samples from MH 108 and LS431. During dry periods, the lift station pumps are active for less than an hour per day. Base flow sampling spanned a multiple day dry period to in order to collect e nough solids at the lift station. At the lift station, the Isco sampler was set to collect an aliquot every lift station pump cycle. At MH108, the Isco was set to collect an aliquot every 4 hours. The filtered solids pump at MH108 was set on a timer at a rate of onehalf hour on, one-half hour off to avoid damage to the pump. A base flow sample was collected at CB173 during the second base flow event. The pump ran for one day without a timer. A timer was installed on the second day for the remainder of sampling. Table 2 lists the dates of the base flow samples.



### 2.2.4 Particle Size Fractionation Samples
Three composite samples were collected for anal ysis of PCBs, metals, and PAHs by grain size fraction. Each sample was split into four si ze categories: <63 μm, 63 to 250 μm, 250 to 500 μm, and >500 μm. A large filtration system consisting of four parallel filter ba gs was constructed in order to obtain enough material for analysis. The sy stem was installed in th e lift station vault to avoid the intermittent flow at the downstream side of the lift station.
The sampler was only activated durin g periods of continuous precipita tion in an effort to collect solids from stormwater rather than base flow . Precipitation events for these samples did not follow the event-based criteria of the regular st orm events (Section 3.1.4). Each sample consisted of four filters from three events.
Filters for the first sample were collecte d between March 26 and March 30, 2010. The second sample was collected between April 27 and May 5. The third sample was a composite of two different time periods. The first set of filters wa s collected April 3, the second on April 9, and the third on May 20.



### 2.2.5 Parking Lot Surface Solids Samples

Filtered solids collected from the MH434 SD are not representative of stormwater runoff. To better evaluate the parking lot as a potential so urce of contaminated sediment to Slip 4, six surface solids samples were collected on July 13, 2010 (Figure 4).

The channel drains in the parking lot were sa mpled for surface material. Because drains D434A and D435B are long, samples were collected from the north and south ends of both of these structures. Additional samples were collected from channel drains D283A and D436A located southeast of Building 3-370. Composite samples were obtained from each of these areas to create a representative sample of sufficient size for analysis. These composite samples were collected from empty parking spaces within several lateral feet of each structure. A separate push broom was used at each location. Surface sweepings incl uded surface material such as fragments of pavement, vehicle debris, soil, gravel, other fine particulate debris, and organic matter from each

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area. Cigarette butts were removed from the sample . Areas of liquid oily ma terial or sheen were avoided when collecting surface solids.
Material collected for each sample was combin ed and homogenized in a clean stainless-steel bowl using a clean stainless-steel spoon. The material was placed in to appropriately sized sample jars, labeled, and stored on ice. Material grea ter than 6 millimeters (1/4 inch) was removed by the sampler prior to filling the sample jars.



### 2.3 Chemical Analysis

All chemical and physical analyti cal procedures were performed by subcontracted laboratories in accordance with Ecology guidelines as outli ned in the SAP/QAPP Addendum (SAIC 2010b).



### 2.3.1 Filtered Susp ended Solids Samples
After collection, all filters were delivered to Analytical Resources, Inc. (ARI), of Tukwila, WA, for processing and analysis. Table 3 lists the fi ltered suspended solids samples selected for analysis. Filtered solids from the “A” filter of the parallel filter setup were first scraped to obtain material for analysis of metals and grain size. Approximately 10 grams of material were needed for metals analysis, and approximately 20 grams fo r grain size. If insufficient sample material was obtained, mercury was analyzed first, fo llowed by other metals, then grain size. The remainder of the filter bag was dried to determine the dry weight of material captured during filtration. The dry filter bag was extrac ted and analyzed for PCB Aroclors.
The “B” filters from Events 6, 7, 8, and 10 were analyzed for PAHs. Due to the volatility of PAHs, the filter was not dried prio r to extraction. The “B” filters from Events 9, 9b, Base Flow Event 1, and Base Flow Event 2 (pending) were dried and weighed by ARI and sent to Axys Analytical Services, Ltd (Axys) of Sidney, BC, fo r analysis of dioxin/furan congeners by Method E1613. Dioxin/furan extracts from Event 9 and 9b were combined for CB423 to ensure enough material for analysis.
Analytical methods are listed in the ch emistry summary (Tables 4 through 7).



### 2.3.2 Whole Water Samples
The carboys containing whole water samples were delivered to ARI for splitting and analysis. Samples from LS431 and MH108 were analyzed fr om Storm Events 6, 7, 8, 9, and 10 and Base Flow Events 1 and 2 for conventional parameters (hardness, pH, alkalinity , anions, total organic carbon [TOC], dissolved organic carbon [DOC], total suspended solids [TSS]), volatile organic compounds (VOC), semi-volatile organic carbon (SVOC), SVOC by Sele ctive Ion Monitoring (SIM), low level PCBs, and total and dissolved metals.
Due to instrument problems at AR I, analysis of metals for Event 6 and Base Flow Event 1 were sub-contracted to Fremont Analytical, Seattle, WA. All analytical methods are listed in the chemistry summary Tables 8 and 9.



### 2.3.3 Particle Size Fractionation Samples
After sampling a precipitation event, filters were delivered to ARI. ARI scraped and composited solids from each filter. Solids were archived un til a sufficient volume was collected. Total mass

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for each sample ranged from 2,500 to 4,300 grams. ARI passed the composited sample through appropriately sized sieves for separation into particle size fractions. During processing, filters and other equipment were rinsed with stormwater collected from the filter housings at the lift station vault.
Samples were alternatively analy zed for PCBs, metals, and PAHs. Analytical methods are listed in Table 10.



### 2.3.4 Surface Solids Samples
Six surface solids samples were delivered to ARI fo r analysis. All samples were analyzed for TOC, grain size, SIM SVOC, PCB Aroclors, and metals . Analytical methods are listed in Table 11.

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## 3.0 Flow Measurement Results

This section presents a summary of flow measurements collected from the NBF lateral SD lines. Measured values for flow are compared to the tota l area in each of the lateral line drainage areas.



### 3.1 Flow Measurements and Precipitation
Flow data logged by the Isco equipment was ma naged using the Isco program Flowlink (Version 5.10.206). All data incorporated into Flowlink are stored in a Mi crosoft Access database. Local precipitation and tide height data were added to the Access database to aid interpretation of the storm hydrographs.



### 3.1.1 Precipitation
Precipitation data from the Seattle Boeing Fiel d-King County Internationa l Airport rain gauge (identified as “KBFI”) was used to represent rainfall at NBF- GTSP (Figure 1). Trace amounts of precipitation are reported as “T”, and were replaced with 0.0254 millimet er (mm) (0.001 inch) when added to the Access database. Precipita tion data from March through July 2010 were added to the database. There were no gaps or other obvious recording issues during this time period.



### 3.1.2 Tide

Validated tidal data from the Seattle tide sta tion (Station ID 9447130) were used to determine tidal inflow at MH434 and LS431. Tide data between October 1, 2009, and June 30, 2010, were downloaded from the National Oceanic and Atmospheric Administration (NOAA) website ( http://coops.nos.noaa.gov/data_menu.shtml ?stn=9447130%20Seattle,%20Puget%20Sound,%20 WA,%20WA&type=Tide%20Data ). All data were added to th e Access database in units of meters above mean lower low water (MLLW).
The heights of the sensors at MH434 and LS 431 were determined by comparing the level measurements made by the Isco flow sensors with the NOAA tide height. The sensor at MH434 sits at 3.32 meters MLLW (10.9 feet). The se nsor at LS431 sits at 3.84 meters MLLW (12.6 feet). Figures showing total flow, tidal height, and rainfall for each event at LS431 and MH434 are presented in Appendix B. The tide was above the level of the sensor at LS431 during Events 5, 7, and 8. The tide was above the level of the se nsor at MH434 during Events 8, 9, 9B, and 10.



### 3.1.3 Stormwater Flow Records

This section summarizes the flow measurements co llected from mid-Februa ry through early July, 2010. A regression between volume of stormwater (l iters) and precipitati on amount (mm) for all recorded rain events was created for each loca tion. The intercept of each regression was set to zero to prevent negative flow volumes at low pr ecipitation amounts. The sl ope of each regression is a constant representing runoff from each of the lateral line drainages.

LS431. Flow through the lift station is described in the preliminary stormwater sampling data report (SAIC 2010a). Briefly, stor mwater runoff from NBF drains to the lift station where it collects in an underground storage vault. Up to four pumps are activated to lift the water above sea level for discharge to Slip 4. Errors with th e flow sensor’s level measurements resulted in

September 2010 Page 11Interim Data Report Expanded Stormwater Sampling

flows from the lift station bei ng underreported. The or iginal flow was m odified by adding a 0.2- meter (8-inch) correction factor to the level data. Volume versus precipitation regressions for both the original (Figure 5a) and mo dified flow (Figure 5b) were ca lculated to show the range of possible values. As in the preliminary data report, the modified flows are used in the report text and figures to describe cond itions at the lift station.

Lift station flow remained between 0.8 and 0.95 m 3 /s (12,700 to 15,000 gpm) through March. Beginning in early April, flows became more vari able between pump cycles. Discussions with the county revealed that the indivi dual pumps rotate activation. The variable flow is either due to calibration issues with the flow sensor or the fa ct that the lift station pumps need servicing.
Base flow through LS431 decreased over the dura tion of expanded stormwater sampling. In midFebruary, base flow was approximately 2,300,000 lit ers (590,000 gal) per day, equating to an average of five pump cycles. Base flow had decr eased to just over four pump cycles per day in early March. By late June, the pumps we re only activated three times per day.
Figures 5a and 5b show the volume versus precip itation relationships between the original and modified flows at LS431. The slope of the original regression is 213,880 lite rs of stormwater per millimeter of precipitation. The slope of the modifi ed relationship is over three times higher at 722,689 L/mm rain (r 2 = 0.923).
There were three periods where measurements at the lift station were not recorded. The first spanned February 5 through February 19. The second spanned March 12 through March 17. The third spanned May 20 through June 1.

MH356. The portion of the south latera l SD line between the lift st ation and MH353 is part of the storage capacity of the lift station. The water le vel in this area is dictated by the cycling of the lift station. As a result, the flow profile at MH 356 is similar to that of LS431 (see Appendix B).
During base flow conditions, one lift station pum p is activated when the water level at MH356 reaches 0.9 meter (3 feet). Over the course of the 8–10-minute pump cycle, the water level drops to 0.35 meter (1.1 feet). After the lift station pump shuts off, the water level rapidly increases to about 0.6 meter (2 feet). The velocity and flow ar e negative during this peri od of rapid level rise. This implies that water is flowing backward over the sensor from elsewhere in the water storage area behind the lift station. The wate r level continues to rise to 0.9 me ter. Velocity is too slow to measure during this period of slow level rise.
The same general pattern is obs erved during precipitation events. However, the large amount of water coming through the south lateral SD line during storm events prevents much of the backward flow of water over the sensor. Given the complexities of the sensor location, it is difficult to determine if there is any base flow input from the south lateral line.
Figure 5c shows the relationship between volume and precipitation at MH356. The slope of the regression is 152,279 L/mm rain (r 2 = 0.912). Flow at MH356 is 21 percent of the modified flow at LS431.
There were gaps in data colle ction at MH356 between April 21 and May 4, and between June 2 and June 10.

MH369. The flow sensor at MH369 wa s installed in a 1.52-meter (5-foot) diameter SD that serves as part of the lift station’s storage overf low in the south-central lateral line. During base

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flow, water level at MH369 varied with the activ ation of the lift stati on. The lift station pump was activated when the water level reached 0.78 meter (2.6 feet). The level dropped to 0.44 meter (1.5 feet) after the pump turned off. Ther e was no negative flow of water over the sensor like that observed at MH356.
During base flow, velocity readings were appr oximately 0.06 m/s (0.2 ft/s) when the lift station was activated. During storm flow, the water near the sensor was agitated due to input from an elevated SD line and from an upstream bend in the south-central SD line. As a result, velocity readings during storm flow were variable and frequently nega tive. Total flows could not be measured during storm events.
When the flow sensor was installed, it was mist akenly believed the only input to MH369 were two 0.3-meter (1-foot) surface drains located 1.2 meters (4 feet) beneath the surface. On May 7, the flow sensor was moved from the 1.52-meter dr ain to the only one of these drains with stormwater flow. The intent was to measure at least a portion of flow entering MH369.
The volume versus precipitation relationship at this location has a slope of 11,045 L/mm rain (r 2 = 0.899). This slope is only 1.5 percent of the m odified LS431 flow. This is much smaller than the expected amount of runoff from this area . Flow from the small drain at MH369 was not representative of total flow in the south-central SD line. Close inspection of the CAD files showed that the larger and deep er line where the sensor was orig inally installed was the correct location for flow through the south-central SD li ne. This location was not suitable for flow measurements due to th e conditions noted above.

None of the flow data from MH369 is considered usable.

MH226. There were no major issues with data co llection at MH226. Flow data spanning the entire time period were successfully measure d. Maximum level readings were 0.21 meter (0.7 feet) and velocity reached a maximum of 1 m/s (3 ft/s). Between precipitation events, level and velocity were slow to reach zero, although th e impact this had on flow was negligible.
The volume versus precipitation relationship is shown in Figure 5d. The slope is 63,569 L/mm rain (r 2 = 0.964).

MH108. The most persistent issue encountered at MH108 during the preliminary stormwater sampling was errors in the ve locity measurements while sa mpling (SAIC 2010a). Velocity readings would increase as the firs t flush of stormwater hit the se nsor, and then remain elevated after the stormwater flow wa s reduced. This issue was present for Events 1 through 5.
The problem was less severe, but not solved, for the expanded stormwater sampling. Flow data from Events 6 and 10 were impacted the most. As a precaution, flow from these two events has been calculated from the volume versus precipit ation regression. Event 7 did not seem to be impacted by this problem. Events 8 and 9 had some issues with velocity, but the velocity profile was still a good match with the storm hydrograph. Flow from Events 7 through 9 is usable as measured.
With the exception of the velocity measuremen t problems during sampling events, there were no issues at MH108. All measurements were succes sfully collected through the end of June. Maximum water levels at MH108 were close to 0.5 meter (1.5 feet), and maximum velocities

September 2010 Page 13Interim Data Report Expanded Stormwater Sampling

approached 0.9 m/s (2.95 ft/s). The slope of th e relationship between volume and precipitation was 111,562 L/mm rain (r 2 = 0.940) (Figure 5e).

CB423. There were no major issues with data collec tion at CB423. Data spa nning the entire time period was successfully measured. Maximum le vel readings were 0.09 meter (0.3 feet) and velocity reached a maximum of 0.55 m/s (1.8 ft/s). As with MH226, level and velocity were slow to reach zero between precipitation events.
Figure 5f shows the volume and precipitation regression for CB423. The slope is 8,335 L/mm rain (r 2 = 0.919). CB423 drains the ar ea around Building 3-380 and is the smallest area draining to the lift station. It represents about 1.2 percent of the total modified flow fr om the lift station.

MH434. Flow data from storm events was not suc cessfully measured at MH434. Tides entered MH434 with a frequency that made it difficult to isolate flows associated with precipitation events. There were a few instances where there was precipitation and no tide. During these times, level readings from the flow sensor did not exceed 0.04 meter (1.5 inches). By comparison, tidal depths ranged up to 0.5 meter (1.5 feet).



### 3.1.4 Event Summaries
The same precipitation criteria we re applied to Storm Events 6 th rough 10 as for the preliminary stormwater sampling (SAIC 2010a). The goal of each storm event was to meet criteria established by Ecology’s Environmental Assessm ent Program’s (EAP) standard operating procedures (SOPs) for stormwater monitoring (Ecology 2009). All sample event figures are presented in Appendix B.
A qualifying storm event was defined as follows:

• At least 3.8 mm (0.15 inch) of rainfall;

• Event duration of at least 5 hours;

• No more than 1 mm (0.04 inch) of rainfall during the preceding 24 hours;

• Sampling duration that includes at least 75% of the storm event hydr ograph, or at least 75% of the first 24 hours of the storm if the storm lasted more than 24 hours;

• Collection of at least 10 sample aliquots , with a minimum volume of 200 mL.
All sampled events had at least 3.8 mm of precipita tion and lasted for at least 5 hours. For Events 7 and 9, 4.6 mm (0.11 inch) and 2.8 mm (0.11 inch) fe ll in the preceding 24 hours, respectively. Less than 1 mm fell before all other events. Dete rmination of storm hydrographs was difficult for many of the events due to the inconsistent nature of spring rainfall. For Event 8, the entire storm hydrograph was sampled. A period of at least 20 hours was sampled for all other events. Nine aliquots were sampled at LS431 for Event 10. A su fficient number of aliquots were collected for all other events.
The only criteria for the baseflow sampling were to avoid precipitation and make sure enough aliquots were collected to be representative of the sampling period. At le ast ten aliquots were collected for each of the base flow events. During the first base flow sa mpling, a trace amount of precipitation fell during the last hour of sampling. During the second full base flow event, a trace amount of precipitation fell midway through sampling.

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## 4.0 Chemistry Results

This section presents and summa rizes analytical results for th e expanded stormwater sampling. Results from the preliminary stormwater sampling are included in the discussion as relevant. The particle size fractionation results and parki ng lot surface solids samples are summarized separately. Chemical data validation results are summarized in Section 5.0.



### 4.1 Filtered Suspended Solids Sampling

Filtered suspended solids sampling results from MH108 and LS431 are summarized in Tables 4 and 5, respectively. Results from sampling of additional lateral lines are presented in Table 6. Results from the additional locations on the no rth lateral SD line are presented in Table 7. Included in each table are the mass of solids from each filter bag, the flow through each totalizer, and if available, the total volum e of stormwater at each location. Laboratory data summaries are available in Appendix C.



### 4.1.1 Physical Parameters

Two measures of filtered solids mass are included in the tables. “Total extracted solids” represents the dried mass of the sample filter (a fter wet weight splits we re removed for grain size and metals) minus the pre-weighed mass of the filte r. In other words, total extracted solids are the mass of material extracted for PCB Aroclor and dioxin/furan congener analysis. “Estimated total solids” represents the total extracted solid s mass plus an assumed dry weight of the grain size and metals splits.

The calculated TSS is the estimated total solid s mass divided by flow through the totalizer. However, the filtration system design likely resu lted in inflated totalizer flows relative to collected solids. One problem was the variable velocity of water thr ough the filtration system over the course of an event. As solids were co llected on the filter, the flow through the filter became restricted. The decrease in flow decreased the line velocity and may have resulted in the settling of some of the larger suspende d solids prior to reaching the filter.
A second problem was related to the seal between the filter bag and the t op of the filter housing. A felt gasket on top of the filter bag formed a seal between the filter bag and the filter housing during sampling. As the filter bag collected solids, the pressure on the bag increased. It is possible that the pressure became high enough dur ing sampling to separate the seal and bypass the filter. This allowed water to flow through the totalizer with out contributing solids to the filter. TSS as measured by the filtration system should be used with reservations. Filtered solids and whole water TSS measurements are compared in Section 4.2.

Because neither of these issues occurred unt il a sufficient amount of solids had accumulated on the filter, the physical and chemical data analyzed from the collected solids are believed to be representative of stormwater solids.
Grain size analysis was conducted when sufficient material could be scraped from the filter bag. Eight samples each were analyzed from the st orm events at MH108 and LS431, plus the two base flow events. There was no consistent partic le size distribution at LS431. Events 4, 7, and 8

September 2010 Page 15Interim Data Report Expanded Stormwater Sampling

had percent fines at 97.4 percen t, 99.6 percent, and 99.3 percen t, respectively. In contrast, percent fines in Events 1, 2, 6, and 9 range d between 13.8 percent a nd 65.9 percent.
The particle size distribution at MH108 was more uniform across storm events. Percent fines for Events 1 through 6 and Events 8 and 9 ranged be tween 37.7 and 66.6 percent. Most of the coarse material for these events was in the sand frac tion. Event 7 differed from the rest with 99.9 percent fines. The particle si ze distribution between silt and cl ay was similar between LS431 and MH108 for Event 7. Both were near 66 percent silt and 33 percent clay.
Percent fines for base flow events were expected to be high. Fines for Base Flow Event 1 (March 20, 2010) at LS431 was 92.4 percent, and 99.9 per cent at MH108 (February 23, 2010). Percent fines for Base Flow Event 2 at LS431 were 99.9 percent. Fines for Base Flow Event 2 at MH108 were 57.9 percent, with 26.2 percent of the particle size distributi on consisting of coarse sand.

Grain size was measured in two other locations representing NBF drainages. Two samples were analyzed from MH434, containing 97.5 and 99 pe rcent fines. Both events were tidally influenced, suggesting river water as the source of the fines. One sample was analyzed from CB423. It contained 81.7 percent fines and 17.2 pe rcent sand. There was visible sand at the bottom of the catch basi n at this location.
Seven grain size samples from four locations we re collected from the north lateral SD line locations. Percent fines ranged betwee n 73.6 and 100 percent for all samples.



### 4.1.2 Chemical Analysis

Metals
Metals results were compared to the Washingt on State Sediment Manage ment Standards (SMS) numeric Sediment Quality Standards (SQS) and Cleanup Screening Levels (CSL) criteria (Washington Administrative Code [WAC] 173-204). PCBs and PAHs were compared to the lowest apparent effects threshold (LAET) and the second LAET (2LAET) (PTI 1988). The LAET and 2LAET are functionally equivalent to the SMS/CSL values, but are not organic carbon normalized. Collection of TOC data from the filters was not possible due to interference from the organic polypropylene filter bag.
Metals were analyzed in all of the filtered soli ds samples collected as part of the expanded stormwater sampling. Silver and arsenic were frequently not detect ed. Of the detected concentrations of silver, onl y one exceeded the SQS/CSL. During Event 9 at CB165, silver concentrations were 160 milligrams per kilogram (m g/kg). Arsenic was detected in about half of the filtered solids samples. Undetected samples frequently exceeded the SQS and CSL criteria due to elevated reporting limits. Detected arseni c concentrations exceeded the criteria at MH369, MH133, and MH138 (Tables 4 through 7).
Chromium and lead had one exceedance each. Chromium exceeded the CSL at MH133 during Event 10 with a concentration of 274 mg/kg. The only exceedance for lead occurred at MH108 during Event 4 of the preliminary stormwater sampling. Copper exceeded the SQS/CSL criteria in a total of six samples. Five of these exceedan ces were from locations in the north lateral SD line. The only other exceedance was Event 10 at MH226 in the nor th central lateral line.

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With the exception of one exceedance at LS431, all exceedances for mercury occurred in the north lateral line (Figure 6). MH133, CB173, and CB165 had the highest average concentrations. Both CB165 and CB173 had indivi dual measurements of mercury over 10 mg/kg (Figure 6c). Average concentrations at MH152 and MH108 were also elevated at levels above 0.7 mg/kg. Unlike other locations in the north SD line, concentrations at MH178 and MH138 were below the SQS. Stormwater at MH178 ente rs from off site at the north end of the drainage. MH138 is at the downstream end of a small dr ainage within the north SD line. Concentrations at LS431 averaged 0.4 ± 0.6 mg/kg. Combined concentratio ns at all remaining drainage lines averaged 0.23 ± 0.09 mg/kg.

Zinc and cadmium were detected at levels that exceed the SQS and CSL criteria at nearly all locations. The highest cadmium concentrations were 78 mg/kg and 102 mg/kg from Events 9 and 10 at CB133, respectively. These were the only two samples collected at CB133. Measured concentrations of cadmium at all other site s ranged between 3.0 and 31.2 mg/kg. Zinc exceeded the CSL in at least one sample at all locations except MH369 and MH178.
Base flow filtered solids samples were an alyzed for metals at MH108, LS431, and CB173. At CB173, base flow concentrations were comparab le to those found during storm events. At LS431 and MH108, base flow concentrations were lower than during storm events with two exceptions. The highest lead concentration at LS431 was measured during Base Flow Event 1. The second highest mercury concentration at MH108 (2.29 mg /kg) was also measured during Base Flow Event 1.
Many of the metals show a pattern where concentr ations are lowest at LS431. This is true for cadmium, chromium, copper, lead, and zinc. It is not clear what could ha ve resulted in higher concentrations in the individua l lateral lines than in the co mbined output. Though not directly comparable, the concentrations of metals from samples collected for size fractionation from the lift station vault (Section 4.3) do ap pear to be higher than con centrations from the downstream side of the lift station.

PCBs
Total PCB concentrations were reported as mi crograms (μg)/filter and converted to μg/kg by dividing by the mass of total extrac ted solids. Total PCBs were calcu lated as the sum of detected Aroclors 1221, 1232, 1242, 1016, 1248, 1254, and 1260. Total PCBs exceeded the LAET or 2LAET in all samples with the exception of Event 9 at MH178.
Average total PCB concentrations at LS431 over 11 events (plus Event 9b) were 1.3 ± 0.8 mg/kg, compared with 6.4 ± 5.9 mg/kg at MH108. MH108 had the highest average PCB concentration of the major lateral lines. Total PCBs exceeded the 2LAET in every sample collected at MH108. Average concentr ations in the other three latera l SD lines were closer to 0.5 mg/kg (Figure 7b).
The base flow samples had some of the highest PCB concentrations measured in this study (Figure 7a and 7c). Base Flow Event 1 and 2 at MH108 had concentrations of 25 mg/kg and 22 mg/kg, respectively. One base flow sample was collected at CB173. The concentration in this sample was 43 mg/kg. There is some question as to whether this sample was representative of base flow or stormwater holdover. The structur e CB173 is lower than the exiting SD. Boeing has observed no base flow entering th e structure from upstream, but ha s indicated that base flow

September 2010 Page 17Interim Data Report Expanded Stormwater Sampling

from downstream may be flowing into this locati on. Two base flow samples were also collected at LS431. Both samples fell within the range of concentrations measured during the storm events. These results indicate that base flow is responsible for higher PCB concentrations in the north lateral SD line, but that these higher concentrations do not have a significant impact at LS431, possibly due to dilution with cleaner ba se flow from other areas of the site.

There were also differences in the Aroclor di stribution between storm event and base flow samples. Aroclors 1254 and 1260 were most commonl y detected in the storm events. Aroclors 1242 and 1254 were detected in the base flow samples.
PCBs in the north lateral SD line were higher th an in other locations. The locations with the highest concentrations were those on the main branch of the north lateral SD line. Concentrations at CB165 averaged 3.8 ± 3.2 mg/kg over the course of three events, while concentrations at CB173 averaged 14.2 ± 3.7 mg/kg. MH178 is locat ed next to CB173. However, unlike CB173, much of the stormwater flow at MH178 comes fr om off site. Concentrations at MH178 were over an order of magnitude lower than those at CB173 (Table 7, Figure 7c).
There is a small positive correlation (r 2 = 0.666) between MH108 and LS431 PCB concentrations, suggesting that elevated c oncentrations at LS431 are influenced by MH108. While there is no overall correlation between rain fall (stormwater volume) and concentration, the two events with the lowest rainfall at both MH108 and LS431 had the highest PCB concentrations.

PAHs

PAHs were measured in filters from Events 3, 6, 7, 8, and 10. Total high molecular weight PAHs (HPAHs) were calculated as the sum of the detected compounds fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k) fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, dibenz(a,h) anthracene, and benzo(g,h,i)per ylene. Total low molecular weight PAHs (LPAHs) are the sum of detect ed compounds of naphtha lene, acenaphthylene, acenapthene, fluorene, phenanthrene, and anthracene.
Phenanthrene frequently exceeded the LAET or 2LAET criteria. Other LPAHs were often not detected. Total LPAH concentrations were typi cally about one-tenth as high as total HPAH concentrations.

Total HPAH concentrations were variable be tween LS431 and MH108 (Figure 8a). However, the average concentration of HPAH across the five events was similar at both locations, at 17.8 mg/kg for MH108 and 18.8 mg/kg for LS431. MH369 had the lowest concentrations found in the main lateral lines, while MH226 and MH356 had the highest (Figure 8b).

Locations in the north lateral SD line were just as variab le. HPAH ranged between 3.8 and 7.0 mg/kg at CB173 and CB165. The concentration fr om the lone sample collected from MH133 was 97.8 mg/kg.

Dioxins/Furans
Dioxin/furan congeners were analyzed from Even ts 2, 4, and 9, with select samples analyzed from Event 9b. The first base flow sample fr om MH108 was also analyzed for dioxin/furan congeners. Results are pending from Base Flow Event 2 for LS431, MH108, and CB173.

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Concentrations of each congener were nor malized to the toxicity of 2,3,7,8-TCDD (tetrachlorodibenzodioxin) using toxic equivalency factors (TEF s) updated by the World Health Organization (WHO) in 2005 (Van den Berg et al . 2006). The toxic equivalent quotient (TEQ) is equal to the sum of the concen trations of individual congene rs multiplied by their TEF. Though all congeners were detected, TEQ values are reported as 0 and 1⁄2 times the method detection limits.
TEQ concentrations at both LS431 and MH108 were much higher for Events 2 and 4 than for Event 9. At MH108, Event 2 and 4 concentrations were 144 and 157 picograms per gram (pg/g) TEQ, respectively. For Event 9, the concentr ation was 10.7 pg/g TEQ. There was a similar decrease at LS431.
All locations were sampled as part of Event 9 or 9b. Of the lateral line locations, MH356 was most similar to the lift station with a c oncentration of 6.57 pg TEQ/g. MH369 and MH226 had concentrations of 17.3 and 44.6 pg TEQ/g, respectivel y. As with the metals, it is not clear why the dioxin/furan concentration at LS431 is lower than those at the other lateral lines. MH343 in the parking lot drainage had a TEQ of 65.5 pg/g.
Samples from the north drain line during Even t 9 ranged from 14.2 to 48.9 pg/g TEQ. There is no clear pattern to the concentrations (Table 7).



### 4.2 Whole Water Sampling

Whole water sampling results from MH108 and LS431 are summarized in Tables 9 and 10, respectively. Concentrations are compared to the lower of the chronic marine water or freshwater criteria (WAC 173-201A-240). Contaminants lacking marine or freshwater criteria are compared to the human health water quality criteria fo r consumption of organisms (HHO) (USEPA 2006). Laboratory data summaries ar e presented in Appendix C.



### 4.2.1 Physical Parameters
Conventional parameters including pH, alkalinity, hardness, TSS, chloride, nitrate, sulfate, DOC, and TOC were measured in each of the whole water samples. pH was consistently higher at LS431, although all events at both locations ranged between pH values of 6.7 and 7.7. Correspondingly, alkalinity was also higher at LS 431. At both locations, alkalinity was highest during the two base flow samples. Chloride varied over the course of 10 events, particularly at LS431. There was no relationship between chlori de and tidal influx into LS431 (Section 3.1.2).
TOC ranged between 6.5 and 21.2 mg/L and averaged 8.7 mg/L at LS431. TOC ranged between 4.3 and 31.8 mg/L and averaged 7.2 mg/L at MH108.
Figure 9 presents whole water TSS for all st orm and base flow events at LS431 and MH108. Calculated TSS from the filtered solids are in cluded for comparison. As stated, TSS from the filtered solids collection are biased low due to excess water flow through the totalizer (Section 4.1.1). Given the problems with calculating TSS fr om the filtration system, whole water TSS are considered more representative of stormwat er conditions. Sampling a nd analytical methods support this. The whole water samples analyzed for TSS were volume weighted over the course of a storm event and were sampled using a consis tent pump flow and velo city. In the laboratory, a known volume of water was passed through a 0.45-micron filter.

September 2010 Page 19Interim Data Report Expanded Stormwater Sampling

The relationship between the whole water a nd filtered solids TSS at LS431 and MH108 can hopefully be extrapolated to the sampling locations in the other drainage basins to allow for better loading estimates.
Average TSS concentrations were 27.5 mg/L at LS431 and 24.2 mg/L at MH108. There was some variability around these averages. Concentrations ra nged between 3.3 and 75.9 mg/L. There was a positive correlation between TSS at the two locations (r 2 = 0.678).



### 4.2.2 Chemical Analysis
Cadmium, copper, lead, and zinc were all detect ed at levels above the marine water criteria (MWC). Copper had more exceedances than the other metals. Average total copper concentrations were 8.5 μg/L at LS431 and 15.7 μg /L at MH108 for all 10 storm events. Base flow concentrations were lower than those for storm events, although tota l copper did exceed the MWC for Base Flow Event 2 at MH108. Dissolved copper concentrations were usually about one half that of total copper.

Total cadmium was detected above the MWC in Event 6 at MH108 and Base Flow Event 1 at both LS431 and MH108. Total lead exceeded the MW C in one storm event at LS431, and three at MH108. Both cadmium and lead were rarely de tected in the dissolved phase. Total zinc was detected at the highest concentration in the w hole water samples. There were two exceedances at LS431 and four at MH108. Base flow concentrations of zinc were four to seven times lower than those found in stormwater.
Mercury was analyzed in all samples but never detected. The reporting limits for mercury are higher than the freshwater criteria (FC) of 0.012 μg/L.
Total PCB concentrations for each event are pres ented in Figure 10. Total PCBs from filtered solids are included for comparis on. PCBs were detected in all samples analyzed from MH108, with concentrations ranging fr om 0.016 to 0.145 μg/L for the stormwater events. Base flow concentrations were higher, at 0.22 μg/L a nd 0.27 μg/L for Base Flow Events 1 and 2, respectively.

Total PCB concentrations at LS431 were lower than MH108. PCBs were undetected in Events 1, 2, and 10. Event 4 was below the FC. All other even ts exceeded the criteria. Using the reporting limit in place of undetected values, the av erage PCB concentration at LS431 was 0.029 for stormwater events. The concentrations from th e base flow samples were lower, at 0.014 and 0.016 μg/L. The conclusion drawn from the base flow samples for filtered solids is the same for whole water: base flow is respons ible for higher concentrations in the north drain lin e, with little impact at the lift station.

There is no direct correlation between PCBs in filtered solids and in whole water at either location (Figure 10). If whole water PCBs are nor malized to mg/kg using the TSS, there is a slight correlation at MH108 (r 2 = 0.553) for all 10 storm events. The same correlation is not present at LS431. TSS normalized whole water con centrations are similar in magnitude to total solids concentrations at both locations.
HPAHs were detected more frequently than LPAHs. Several HPAHs, including benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k) fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, and dibenz (a,h)anthracene, have a water quality criterion (HHO) of

Page 20 September 2010Expanded Stormwater Sampling Interim Data Report

0.018 μg/L. These compounds frequently exceeded the HHO at LS431. HPAH concentrations were typically higher at LS431. The HHO criterion wa s exceeded with about half this frequency at MH108 (Tables 9 and 10).
Average HPAH was 2.1 μg/L at LS431 and 1.9 μg/L at MH108. Base flow concentrations were an order of magnitude lower. PAHs in stor mwater are likely a result of surface runoff.
Additional SVOCs were analyzed but seldom det ected. Bis(2-ethylhexyl)ph thalate was detected at levels that exceeded the HHO criteria during Events 4 and 7 at MH108. Additional phthalates, including di-n-octyl phthalate, di ethylphthalate, and di-n-butyl pht halate, were detected at both locations.
VOCs detected as part of the preliminary stormw ater sampling were also present in Events 6 through 10. Methylene chloride, acetone, and 2-butanone were detected in most samples. Each of these VOCs was detected in at least one of the base flow samples at each location at concentrations comparable to the stormwater samples.



### 4.3 Particle Size Fractionation

Results of the particle size fractionation anal ysis are described in the Slip 4 Sediment Recontamination Modeling Report (SAIC 2010c). Br iefly, the highest total PCB concentrations were found in the finest (<63 μ m) and coarsest (>500 μ m) fractions in all three samples. Concentrations in both of these fractions we re similar, ranging from 7.7 to 13.6 mg/kg. The concentrations in the medium two size fractions were 20 to 50 percent of th ese values (Table 10).
The metals cadmium, chromium, copper, lead, me rcury, and zinc were detected in all size fractions from Composite 1. The highest concentrations of metals were found in the fine fraction and the second highest concentrations in th e coarsest fraction.

Both LPAHs and HPAHs were detected in a ll fractions analyzed. Again, the greatest concentrations were in the fine and coarse frac tions. In Composite 4, the coarsest fraction (>500
μ m) contained LPAHs and HPAHs an order of magnitude higher than other fractions.
The percentage of each grain size fraction in th e total composites is unknown. As such, sample concentrations cannot be reconstructed. This pr events a direct comparison of filtered solids between the lift station vault and down stream side of the lift station.



### 4.4 Surface Solids Samples

Parking lot sweep samples are summarized in Table 12. Grain size anal ysis was conducted on each of the six samples. Total fines ranged from 7.9 to 17.2 percent. Total sand was the dominant fraction in all samples, falling in the narrow range of 75.7 to 84.2 percent. The sweep samples consist of a much coarser grain size distribut ion than the TSS samples collected by the filter bags.
PCBs, metals, and PAHs were analyzed in each of the samples. Concentrations were similar across the six locations for all analytes. The results were compared to the LAET and 2LAET criteria on the assumption that a po rtion of these solids may end up in the SD system (Table 12).

September 2010 Page 21Interim Data Report Expanded Stormwater Sampling

Aroclors 1254 and 1260 were detect ed at all locations, and Aroclo r 1248 was detected at four of the locations. Total PCB concentrations ranged between 0.116 and 0.34 mg/kg, with five of the locations exceeding the LAET.

Concentrations of most metals were lower than those found in the filt ered solids. Lead and chromium were exceptions. Concentrations of th ese two metals were toward the high end of the range of concentrations from the filtered solids. PAH concentrations were lower than in the filtered solids. Total HPAH ranged between 1.02 and 6.34 mg/kg. None of the PAH or metal concentrations exceeded the LAET.

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## 5.0 Quality Assurance/Quality Control

A Level IV data validation was re quested on all data. The data va lidation report is still pending. All tables will be updated with qualified values upon receip t of the report.

September 2010 Page 23Interim Data Report Expanded Stormwater Sampling



## 6.0 Summary

Expanded stormwater sampling was a continuation of the preliminary sampling at NBF-GTSP. As part of this effort, the collection of filtered suspended solids and whole water samples continued at LS431 and MH108 for five more stor m events and two base flow events. Sampling of filtered suspended solids was added at the downstream end of the other lateral SD lines, and at select locations in the north SD line. Continuous flow measurements were collected at the lift station and at each of the onsite drainages.

Sufficient flow measurements were co llected from LS431, MH108, MH226, CB423, and MH356 to characterize the relationship between precipitation amount and the volume of stormwater runoff for each location. In addition, the presen ce of the flow mete rs in each lateral line helped to determine the extent of the st orage capacity of the lif t station. Both MH369 and MH356 were affected by the activat ion of the lift station pumps.

Concentrations of metals in f iltered suspended solids were variable. Cadmium and zinc exceeded the LAET criteria at nearly all locations, while me rcury concentrations were highest in the north lateral SD line. Concentrations of most metals in base flow were lower than the stormwater samples.

PCB concentrations for both filtered solids and whol e water were highest in the north lateral SD line. Base flow concentrations from the north SD line had higher concentrations than the storm events. However, base flow concentrations at LS431 were within the same range as the storm event samples, suggesting the inflow of PCBs in the north drain line were not enough to alter base flow concentrations at th e lift station. The Aroclor distri bution of PCBs varied between storm events and base flow. Aroclors 1254 and 1260 were most commonly detected in stormwater, while Aroclors 1242 and 1254 were most common in base flow.
Additional parameters were analyzed in the whole water samples. Phthalates were detected occasionally, but only bis(2-et hylhexyl)phthalate exceeded the HHO criteria. Methylene chloride, acetone, and 2-butanone continued to be detected in whole water samples. Base flow concentrations of these VOC were sim ilar to the storm event concentrations.
Filtered solids samples from MH434 were not repr esentative of parking lot runoff due to tidal intrusion. Six surface sweep samples were collected to determine the poten tial of the parking lot as a source to Slip 4. PCBs exceeded the LAET in five of the samples, but concentrations were lower than those in the lateral SD lines. No metals or PAHs exceeded the LAET criteria.

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## 7.0 References

Ecology. 2009. Standard Operating Procedure for Automatic Sampling for Stormwater Monitoring. Washington State Departme nt of Ecology. Draft Version 1.0.
Landau. 2010. Revised Work Plan, Storm Drain System Catch Basin, Manhole, and Oil/Water Separator Sampling and Storm Drain System Cleaning, North Boeing Field, Seattle, Washington. Prepared for The Boeing Co mpany by Landau Associ ates, Edmonds, WA. March 26, 2010.
PTI. 1988. Sediment Quality Va lues Refinement: 1988 Update and Evaluation of Puget Sound AET. Volume I. Final Report. Prepared for Tetra Tech, Inc., Bellevue, WA, and the U.S. Environmental Protection Agency, Regi on 10, Seattle, WA. Prepared by PTI Environmental Services, Bellevue, WA.
SAIC. 2009a. North Boeing Field/Georgetown Steam Plant Site Remedial Investigation/ Feasibility Study: Sampling and Analysis Plan and Quality Assurance Project Plan for Preliminary Stormwater and Filtered Susp ended Solids Sampling. Prepared for Toxics Cleanup Program, Northwest Regional Office, Washington State Depa rtment of Ecology, by SAIC, Bothell, WA. August 2009.
SAIC. 2009b. North Boeing Field and Georgeto wn Steam Plant, Supplemental Report: Summary of Existing Information and Identifi cation of Data Gaps. Prepared for Toxics Cleanup Program, Northwest Regional Office, Washington State Depa rtment of Ecology, by SAIC, Bothell, WA. August 2009.
SAIC. 2010a. North Boeing Field/Georgetown Steam Plant Site Remedial Investigation/ Feasibility Study: Preliminary Stormwater Sampling Interim Data Report. Prepared for Toxics Cleanup Program, Northwest Regional Office, Washington State Department of Ecology, by SAIC, Bothell, WA. May 2010.
SAIC. 2010b. North Boeing Field/Georgetown St eam Plant Site Remedial Investigation/ Feasibility Study: Work Plan and SA P/QAPP Addendum Expanded Stormwater Monitoring. Prepared for Toxics Clea nup Program, Northwest Regional Office, Washington State Department of Ec ology, by SAIC, Bothell, WA. March 2010.
SAIC. 2010c. North Boeing Field/Georgetown Steam Plant Site Remedial Investigation/ Feasibility Study: Slip 4 Sediment Recont amination Modeling Report. Prepared for Toxics Cleanup Program, Northwest Regional Office, Washington State Department of Ecology, by SAIC, Bothell, WA. July 2010.
USEPA. 2006. National Recommended Water Qual ity Criteria. Prepared by United States Environmental Protection Agency, Office of Water, Office of Science and Technology. 2006.

September 2010 Page 25Interim Data Report Expanded Stormwater Sampling

Page 26 September 2010 Van den Berg, M., L.S. Bimbaum, M. Denison, M. De Vito, W. Farland, M. Feeley, H. Fiedler, H. Hakansson, A. Hanberg, L. Haws, M. Ro se, S. Safe, D. Schrenk, C. Tohyama, A. Tritscher, J. Tuomisto, M. Tysklind, N. Walker, and R. Peterson. 2006. The 2005 World Health Organization Re-Evaluation of Human and Mammalian Toxic Equivalency Factors for Dioxins and Di oxin-like Compounds. Prepared for the World Health Organization (WHO). ToxSci Advance A ccess published July 7, 2006. Published by Oxford University Press on behalf of the Society of Toxicology.