HAZARD RANKING SYSTEM (HRS) DOCUMENTATION RECORD COVER SHEET

Name of Site : General Dynamics Longwood

EPA ID No. : FLR000091322

Contact Persons

Documentation Record : Barbara Alfano, Remedial Project Manager U.S. Environmental Protection Agency, Region 4 61 Forsyth Street, S.W., 11 th Floor Atlanta, Georgia 30303 (404) 562-8923

Jennifer Wendel, National Priorities List Coordinator U.S. Environmental Protection Agency, Region 4 61 Forsyth Street, S.W., 11 th Floor Atlanta, Georgia 30303 (404) 562-8799

Pathways, Components, or Threats Not Scored

The surface water migration, soil exposure, and air mi gration pathways were not scored in this Hazard Ranking System (HRS) documentation record because they are not expected to significantly contribute to

the overall site score.

Surface Water Migration Pathway : Between 1988 and 2005, surface water and sediment samples have been collected from the drainage channel (unname d ditch) located between the General Dynamics property and the Sprague Electric Company (SEC) pr operty, as well as Soldier Creek located downstream of the drainage ditch. Surface water and/or sedimen t samples collected from the drainage ditch contained trichloroethylene (TCE) and 1,1-dichloroethylene (DCE ). No constituents were detected in the surface water and sediment sample collected from Soldier Cr eek (Ref. 8, Tables 4-1 and 4-2, Figure 2-2). Surface water runoff from the General Dynamics propert y drains into the east-west trending drainage ditch on the northern boundary of the SEC property. The ditch then flows about 0.5 mile east and northeast, where it discharges into Soldier Creek. So ldier Creek flows about 1.7 miles southeast into Lake Jesup which ultimately drains into the St. Johns River (Ref. 8, p. 3-1, Figure 2-2).

Soil Exposure and Air Migration Pathways : Site-related contaminants have not been detected in surface soil samples collected from 0 to 2 feet below la nd surface (Refs. 8, pp. 4-11, 4-12; 10, pp. 24, 25; 46, Table 1, Figure 1; 49, Figure 3; 65; 77, p. 15; 89). Residential areas are located in the vicinity of the General Dynamics property (Refs. 10, p. 18; 11). Air and residential surface soil contamination has not been documented (Refs. 8, pp. 4-11, 4-12; 10, pp. 24, 25; 46, Table 1, Figure 1; 49, Figure 3; 65). As of June 2007, five people work at the Gould (referred to as General Dynamics in this HRS documentation record) property (Ref. 10, p. 35). The property cons ists of three buildings, paved parking and unpaved grass areas (Ref. 10, pp. 35, 51). The population within one mile is about 5,353 people (Ref. 14, pp. 1, 4). No air samples were collected at the General Dyna mics property during the site inspection (Ref. 10, p. 37). The residential population within 4 radial mil es of the property is about 94,432 people (Ref. 14, pp. 1, 7).1 HAZARD RANKING SYSTEM (HRS) DOCUMENTATION RECORD

Name of Site: General Dynamics Longwood

EPA Region: 4

Date Prepared: March 2009 Date Revised: September 2010

Street Address of Site*: 1333 North US Highway 17/92

City, County, State, Zip: Longwood, Seminole County, Florida, 32750

General Location in the State: Central portion of state, along the eastern coast

Topographic Map: Casselberry, Florida, 1981

Latitude: 28.71662 < North

Longitude: -81.32122 < West

The coordinates above for General Dynamics were me asured at the southeastern corner of Building 3 (Refs. 8, Figure 1-2; 13).

* The street address, coordinates, and contamin ant locations presented in this HRS documentation record identify the general area in which the site is located. They represent one or more locations EPA considers to be part of the site based on the screeni ng information EPA used to evaluate the site for NPL listing. EPA lists its national priorities among the kno wn “releases or threatened releases” of hazardous substances; thus, the focus is on the release, not precisely delineated boundaries. A site is defined where a hazardous substance has been “deposited, stored, placed , or otherwise come to be located.” Generally, HRS scoring and the subsequent listing of a release re present the initial determination that a certain area may need to be addressed under CERCLA. Accordingly, EPA contemplates that the preliminary description of facility boundaries at the time of scori ng will be defined as more information is developed

as to where the contamination has come to be located.

Migration Pathway Pathway Score
Ground Water Migration Pathway 100.00
Surface Water Pathway NS
Soil Exposure Pathway NS
Air Migration Pathway NS

HRS SITE SCORE 50.00

Note:

NS Not scored2 WORKSHEET FOR COMPUTING HRS SITE SCORE

S pathway S 2 pathway
Ground Water Migration Pathway Score (S gw ) 100 10,000
Surface Water Migration Pathway Score (S

sw ) NS NS
Soil Exposure Pathway Score (S

s ) NS NS
Air Migration Score (S

a ) NS NS

S 2

gw + S 2

sw + S 2

s + S 2

a 10,000

(S 2

gw + S 2

sw + S 2

s + S 2

a )/4 2,500

/(S 2

gw + S 2

sw + S 2

s + S 2

a )/4 50.00

Note:

NS = Not scored3 Table 3-1 --Ground Water Migration Pathway Scoresheet Aquifer Evaluated: Interconnected Surficial and Upper Floridan Aquifers

Factor Categories and Factors Maximum Value Value Assigned

Likelihood of Release to an Aquifer:

1. Observed Release 550 550

2. Potential to Release:

2a. Containment 10 NS 2b. Net Precipitation 10 NS 2c. Depth to Aquifer 5 NS

2d. Travel Time 35 NS 2e. Potential to Release [lines 2a(2b + 2c + 2d)] 500 NS 3. Likelihood of Release (hi gher of lines 1 and 2e) 550 550

Waste Characteristics: 4. Toxicity/Mobility (a) 100 5. Hazardous Waste Quantity (a) 10

6. Waste Characteristics 100 6 Targets:

7. Nearest Well 50 20 8. Population:

8a. Level I Concentrations (b) 0.00

8b. Level II Concentrations (b) 0.00

8c. Potential Contamination (b) 6,613.9 8d. Population (lines 8a + 8b + 8c) (b) 6,613.9

9. Resources 5 0

10. Wellhead Protection Area 20 5.00 11. Targets (lines 7 + 8d + 9 + 10) (b) 6,638.9 Ground Water Migration Score for an Aquifer: 12. Aquifer Score [(lines 3 x 6 x 11)/82,500] c 100 100.00 Ground Water Migration Pathway Score: 13. Pathway Score (S gw ), (highest value from line 12 for all aquifers valuated) c 100 100.00

Notes:

NS = Not scored

a = Maximum value applies to waste characteristics category

b = Maximum value not applicable

c = Do not round to nearest integerI01,000500Feet 2009-1-29 \GIS_Workspace\TTEMI-05-003-0038_General_Dynamics_Longwood\Figures\GIS\MXDs\Site Location Maps\GEN DYNAM SITE LOC MAP 1-29-09.mxd TTEMI-KY dale.vonbuschFIGURE 1FACILITY LOCATIONUnited States Environmental Protection AgencyGENERAL DYNAMICS LONGWOODLONGWOOD,SEMINOLE COUNTY,FLORIDATDD No.TTEMI-05-003-0038SEMINOLE COUNTY,FLORIDAMAP SOURCE:Reference 15, pp. 1 through 11.USGS, Casselberry, FLTopographic Quadrangle, 1981.GENERAL DYNAMICS1:12,000LEGENDGeneral DynamicsSprague Electric Company1 7 / 9 2FORMER PAINT ANDLEGENDBuilding/Structure OutlineFormer Structures/FeaturesGeneral Dynamics Property Boundary!.Contaminated SoilSample location

N U S H I G H W A YBUILDING 1PLATING BUILDINGMAINTENANCEBUILDINGSource:References 10, Figures 4, 6, and 7; 15, pp. 1 through 9;16, pp. 8 through 15, Exhibit 1; 17, pp. 18, 19, Exhibit 1;46, Table 1, Figure 1; 49, Figure 3; 50, pp. 15, 16;88, pp. 10, 11, 14, 15. ttemi-ky dale.vonbuschBUILDING 3BUILDING 2!.FORMER SHEDAPPROXIMATE LOCATION OFFORMER AST010050FeetI1:1,200Aerial Photograph: DigitalGlobe/Globe Explorer, 3/08.Note:AST – Above Ground Storage TankAPPROXIMATE LOCATION OFSOURCE #2FORMER VAPORDEGREASERUnited StatesEnvironmental Protection AgencyCONTAMINATED SOILGENERAL DYNAMICS LONGWOODLONGWOOD,SEMINOLE COUNTY,FLORIDATDD No.TTEMI-05-003-0038FIGURE 2SOURCE LOCATION 2009-2-19 \GIS_Workspace\TTEMI-05-003-0038_General_Dynamics_Longwood\Figures\GIS\MXDs\Source Location Maps\GEN DYNAM SOURC LO CS 2-19-08.mxd

# Former general location of Source 1 and associated Observed Release 

# Legend
General Dynamics Longwood Site

SEC Superfund

Alternative Site

Bldg 1

Bldg 2 Bldg 3 

## General location of Source 2 and associated Observed Release General Dynamics Longwood Site

SEC Superfund

Alternative SiteLegend

GENERAL DYNAMICS

FACILITY AREA

SEC FACILITY AREA

MAXIMUM POSSIBLE

BACKGROUND

UPGRADIENT AREA

REVIEWED UPGRADIENT

SAMPLE LOCATION BLDG 1

BLDG 2 BLDG 3

MW-5B 1,700 μg/L of 1,1-DCE

SEC FACILITY

AREA

SOURCE 2 GENERAL DYNAMICS

FACILITY AREA

SOURCE 2

OBSERVED RELEASE

SAMPLE LOCATION
(DPGW-34 26,500 μg/L of 1,1-DCE)

SOURCE 2

OBSERVED RELEASE

BACKGROUND

SAMPLE LOCATION
(DPGW-23)

OBSERVED RELEASE BACKGROUND

SAMPLE LOCATION
(DPGW-26)8 REFERENCES

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50. Southeast Accutest Laboratories. Technical Repor t for URS Corporation, Sampling Date June 8, 2005. February 7, 2007. 102 Pages.

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56. Willard Harms, Project Coordinator, URS Corpora tion. Project Note. Subject: Absence of Liner on the General Dynamics Property. October 9, 2008. 1 Page.

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### SITE DESCRIPTION

The General Dynamics Longwood site consists of a c ontaminated soil source on the eastern portion of the General Dynamics property (Source No. 2) and a rel ease of a hazardous substance (1,1-DCE) to ground water (see Figures 2 and 3 of this HRS documentation record). A significant increase of 1,1-DCE has been documented underlying and downgradient of the c ontaminated soil source (Source No. 2) at the site (see Section 3.1.1 Observed Release of this HRS documentation record).

The General Dynamics Longwood site is located w ithin the General Dynamics property (also known as the Gould property) (Ref. 10, p. 3) (see Figures 2 and 3 of this HRS documentation record). The General Dynamics property is located at 1333 North US Highway 17/92 in Longwood, Seminole County, Florida (Ref. 12, pp. 5, 6) (see Figure 1 of this Hazard Ranking System [HRS] documentation record). More specifically, the geographic coordinates as measured from the southeastern corner of Building 3 are latitude 28.71662o north and longitude -81.32122o west (Refs. 3; 13). The General Dynamics property consists of four parcels covering an area of about 10 .42 acres (Refs. 15, pp. 1 through 9; 19, p. 1 through 5; 20). Located on the eastern portion of this propert y is the scored source (Source No. 2). The western part of this property contains what was originally established as Source 1, and is part of the Sprauge Electric Company (SEC) Superfund Alternative Approach (SAA) site (see Figure 3 of this HRS documentation record).

Land uses surrounding the property are predominately vacant, residential, industrial, and mixed commercial (Refs. 10, pp. 49, 50; 11; 15, pp. 10 through 19; 26, p. 2). The General Dynamics property is bounded by vacant land to the north, Sprague Electri c Company (SEC) to the south, vacant commercial land to the east, and Highway 17-92 to the west (R ef. 15, pp. 10 through 19). The neighboring SEC property is about 12-acres and contains office and production buildings that contain capacitor manufacturing and assembly areas and a machine shop; a loading dock; storage areas; a fire protection well; septic tanks and associated drain fields; a retention pond, and one side of a drainage ditch located along the northern property boundary (Ref. 26, pp. 2, 3). A day care center is located to the east and adjacent to SEC (Ref. 21, p. 23).

The General Dynamics property consists mostly of pa ved parking and unpaved grass areas. Access to the back of the property is restricted by a locked chai n link fence (Ref. 10, p. 35). Structures on the General Dynamics property include three large manufacture build ings (Building Nos. 1, 2, and 3) among smaller buildings (Refs. 3; 10, p. 51; 16, pp. 9 through 13, Exhibit 1) (see Figure 2 of this HRS documentation record). Building Nos. 1, 2, and 3 were built at separate times between 1959 and 1965 (Refs. 3; 47, p. 4). Building 1 contained the lobby, plant manager’s office, and personnel (Refs. 3; 16, p. 12, Exhibit 1). Building 2 contained an engineering drafting and test area (Refs. 3; 16, p. 11, Exhibit 1). Building 3 contained the manufacturing area, PC soldering, storag e area, and a vapor degreaser (Refs. 3; 16, pp. 9, 10, 11, 14, 15, Exhibit 1). A building which containe d a maintenance shop is located to the northeast of Building 1 (Refs. 3; 10, p. 51). A shed was locat ed to the east of Building 3 which held 55 gallon containers of TCE (Ref. 17, pp. 18, 26, Exhibit 1). Painting and plating occurred east of Building 1 (Ref. 3).

From about 1961 to December 1979, the General D ynamics facility (and its predecessors) operated on a larger parcel of land. In December 1979, SEC acqui red a strip of east-west trending land to the south and a rectangular portion to the east (Ref. 8, p. 1-5, Figure 1-2).16 OPERATIONAL AND REGULATORY HISTORY

Limited information exists on the operational history at General Dynamics. According to depositions of former General Dynamics’ employees, General Dy namics (and its predecessors) manufactured printed circuit boards (Ref. 16, pp. 6, 7).

Tenets at the General Dynamics property included Dynatronics (1959 to 1965); General Dynamics Corp. (1966 to 1978); Stromberg-Carlson, a subsidiary of General Dynamics Corp. (1979 to 1982); General Dynamics Land Systems, a subsidiary of General Dy namics Corp. (1983); Lexar Corporation and United Technologies Comm. Co. (1984 to 1985); and Lexar Corporation, UTCC, and Telex Computer Products (1986 to 1988). Gould Publications purchased the property in 1993 (Ref. 18). Gould Publications conducted printing and publicati on operations and, as of 2007, conducts wholesaling and warehouse activities (Ref. 10, p. 3).

General Dynamics manufactured printed circuit boards (R efs. 16, pp. 6, 7; 41, p. 5). Printed circuit

boards are metal clad dielectrics with conductors im printed onto one or both sides of the board. The general assembly process of the printed circuit boards includes placing electrical components on the boards, the boards are then fluxed and components ar e affixed and soldered to the boards. General contaminants include: water insoluble or oily mate rials; water soluble materials including rosin flux activators, sodium chloride, and plating and etching salts; and particulates, such as dust, and machining, drilling, and punching fragments. A cleaning process is needed to remove residues from the board. Chemicals used in the cleaning process include chlori nated solvents such as trichloroethylene (TCE), 1,1,1-trichloroethane (TCA), perchloroethylene (PCE), and 1,1,2-trichloro-1,2,2-trifluorethane, as well as various non-chlorinated solvents, such as acetone and alcohol (Refs. 42, p. II-9; 43, p. 5). According to a previous employee at General Dynamics, the manufacture of printed circuit boards included the use of a liquid resist (KPR). The panels would be placed in a copper roller coder material that would deposit a photo resist on to the boards. The boards would then be baked for several minutes followed by exposure to ultraviolet light. The boards were then placed in a degreaser (Ref. 41, p. 9). The vapor degreaser was about 4 feet wide by 4 feet deep by 5 feet high. The chemical used in the vapor degreaser was TCE (Ref. 41, pp. 10, 11). About 25 to 30 gallons of TCE we re placed into the vapor degreaser a couple times a week (Ref. 41, pp. 11, 12, 13). TCE was stored in 55-gallon drums in a shed located to the east of Building 3 (Ref. 17, pp. 18, 26, Exhibit 1) (see Figure 2 of this HRS documentation record). At an unspecified time, TCE was stored in an above ground storage tank (AST) located outside Building 3 near the vapor degreaser (Ref. 88, pp. 10, 11, 14, 15) ( see Figure 2 in this HRS documentation record). Additional vapor degreasers were located throughout the facility; however, the location of all the degreasers, as well as the solvents used in them, are unknown (Ref. 41, p. 8). Also, an underground storage tank is located near Source No. 2 (Ref. 8, pp. 1-4, 2-2, Figure 1-2)

According to Florida Department of Environmenta l Protection (FDEP) personnel, no regulatory file information exists concerning operations at the Gene ral Dynamics property (Ref. 44, p. 1). However, a hazardous waste compliance inspection was conducted by FDEP in 2003 (Ref. 45, p. 2). Waste found on the property included acetic acid, ammonium thiosulfate, silver chloride, benzyl alcohol, paint, and ink, among others (Ref. 45, pp. 2, 6 through 13).

The adjacent SEC facility manufactured film capac itors on the property from 1959 to 1992. From approximately 1959 to December 1964, a portion of the SEC property was owned by Dearborn Electronics of Delaware, Inc. (Dearborn). Both SEC and Dearborn manufactured film capacitors at the SEC property. Film capacitors were assembled, sold ered, impregnated with wax mineral oil or silicon oil in a pressurized chamber, and then cleaned in a vapor degreaser (Ref. 26, p. 3). The chemicals TCA and TCE were used as cleaning agents in the vapor degreaser (Ref. 8, p. 1-5).

The breakdown products of TCE include 1,1-dichloroet hylene (DCE), cis-1,2-DCE, trans-1,2-DCE, and vinyl chloride. The breakdown products of PCE include TCE, 1,1-DCE, cis-1,2-DCE, trans-1,2-DCE, and vinyl chloride (Ref. 52, p. 24). The breakdown products of 1,1,1-TCA include 1,1-DCE (Ref. 52, p.17 B4-63). Deposition testimony of former General Dynamics employees indicates that TCE and 1,1,1-TCA (referred to in the testimony as “1,1,1-Tric”) were used at the General Dynamics facility (Ref. 41, pp. 9 through 13; 88, pp. 7, 8). Solvents such as TCE, PCE, and 1,1,1-TCA are commonly used in printed circuit board manufacturing processes for metal cleani ng and vapor degreasing (Refs. 43, p. 5; 53, p. 177). 1,1-DCE has been detected in the contamin ated soil source and in ground water underlying and downgradient of the source (see sections 2.2.2 Hazar dous Substances Associated with the Source and 3.1.1 Observed Release of this HRS documentation record).

PREVIOUS INVESTIGATIONS

The majority of investigations which include the General Dynamics property have been performed in conjunction with the SEC property. As a result of c ontaminant delineation efforts, many of the sampling investigations have included the General Dyna mics property (Ref. 8, pp. 4-4 through 4-15).

As a result of a former employee’s allegation that SEC disposed solvents into the septic system located on the SEC property, FDEP’s (then known as Florida Depa rtment of Environmental Regulation, henceforth referred to as FDEP) Operations Response Team conducted a preliminar y ground water investigation at SEC in July and October 1984. Six shallow sandpoi nt well ground water samples were collected and analyzed for volatile organic compounds (VOC) (Ref. 22, pp. 3, 6; 26, p. 3). No VOCs were detected in an upgradient designated background sample. One or more of the following compounds were detected in the downgradient sandpoint wells: chloroethane, 1,1-dichloroethane (DCA), 1,1-DCE, 1,2-DCE, 1,1,1- TCA, and TCE (Ref. 22, p. 9).

In October 1985, E.C. Jordan conducted a prelimin ary assessment (PA) on behalf of FDEP. The PA noted that FDEP had issued a Warning Notice to SEC on January 11, 1985, regarding the high concentration of TCE, 1,1-DCE, and TCE in the ground water underlying the SEC property. During a windshield survey conducted on August 22, 1985, effluent was seen flowing from a polyvinyl chloride (PVC) pipe into the drainage ditch located on the SEC property. It was recommended that the facility be inspected to ensure that illegal di scharges to the septic system were no longer occurring and to sample the discharge to the ditch to ensure that it was not ne gatively impacting surface water quality (Ref. 23, pp. 1, 2).

FDEP issued a consent order (CO) on January 9, 1986 (Ref. 24, Appendix A, p. 1). On February 10, 1986, SEC submitted a preliminary contamination asse ssment plan (PCAP) to FDEP; the plan was approved by FDEP on April 23, 1986 (Ref. 24, Appendix A, p. 2). During the PCAP review period, SEC located an underground storage tank (UST) on the southern portion of the property, and analyzed its contents (Ref. 25, p. 1, Figure 1). The UST contained the following VOCs: 1,1-DCA; 1,1-DCE; 1,1,1- TCA; and TCE (Ref. 25, pp. 11, B-1). In May 1986, sixteen ground water samples were collected on the SEC property. The following hazardous substances were detected in the ground water samples collected: 1,1-DCA; 1,1-DCE; cis-1,2-DCE; methylene chloride; PCE; 1,1,1-TCA; and TCE (Ref. 25, pp. 3, 4, 10). The greatest concentrations of total VOCs, 6,617 milligra ms per liter (mg/L), were detected in the north central portion of the SEC property. No samples we re collected on the General Dynamics property (Ref. 25, pp. 9, 10). The UST and underlying contamin ated soil (from ground surface to 10 feet below land surface [bls]) were removed in 1987, and the excavation was filled with soil transported from off site. Approximately 5,500 pounds of soil were removed from the property (Ref. 24, pp. 2, 3, 104 through 107).

Geraghty & Miller, Inc. collected ground water samp les from newly installed monitoring wells in 1988 and 1989 (Ref. 6, pp. 1, 5, 7, 8). Three mon itoring wells were installed on the General Dynamics property, MW-13, MW-14, and FL-3, with total depths of 40, 15, and 156 feet, respectively. These wells are located on the eastern portion of the General Dynamics property (Refs. 6, Figures 8, 9, and 10; 71, pp. 18, 19, 33). The greatest concentrations of TCE disc overed in monitoring wells were detected in sample MW-5 (total depth of 44 feet bls) in August 1988 and again in November 1989. MW-5 is located on the north central portion of the SEC property (Refs. 6, Tables 6 and 7, Figure 6; 71, p. 10).18 In March 1991, Geraghty & Miller installed two we lls on the western portion of the General Dynamics property (Refs. 27, p. i, Figure 1; 71, pp. 21, 34). Monitoring well MW-16 (MW-16A) was installed to a depth of 16 feet bls and FL-4 (FL-4C) was installed to a depth of 130 feet bls (Refs. 8, Table 2-4; 71, pp. 21, 34). Samples collected in March 1991 from monitoring well MW-16 (MW-16A) contained TCE at a concentration of 380 μg/L. Constitu ents related to the General Dynami cs and/or SEC properties were not detected in the sample collected from FL-4 (Ref. 27, Attachment A, pp. 3, 5).

In October 1995, Great American Financial Resource s, Inc. (GAFRI) (successor in interest to SEC) retained Woodward-Clyde Consultants (now URS Co rporation [URS]) to conduct remediation activities at the SEC property (Ref. 8, pp. ES-1, 4-8). In January 1996, URS submitted a revised interim remedial action plan to FDEP. Three horizontal wells were in stalled in the upper surficial aquifer along the north boundary of the SEC property to capture impacted sh allow ground water and prevent the movement of the shallow volatile organic hydrocarbon (VOH) plume to th e north (Ref. 8, p. 4-8). One recovery well was installed in the lower surficial aquifer to provide so me hydraulic control, recover contaminants from the B-zone (lower surficial aquifer), and to create add itional upward pressure to further reduce the possibility of vertical migration of contaminants into the Florid an aquifer (Ref. 8, pp. 1-9, 4-8). The ground water treatment system began operation in July 1997. Six ad ditional A-zone (upper surf icial aquifer) wells, one B-zone well, and one Floridan aqui fer well were installed in 1996 to support performance monitoring (Ref. 8, pp. 1-9, 4-8).

In 2001, URS, on behalf of GAFRI, conducted add itional contamination assessment activities at the SEC and General Dynamics properties (Refs. 8, pp. 4-10, 7-2; 8a; 46, p. 1; 79). The additional assessment activities were conducted to investigate the cause of increasing levels of halogenated compounds in the A-zone (about 12 to 17 feet bls) and the B-zone (about 20 to 46 feet bls) of the surficial aquifer (Ref. 46, p. 1, Figure 3). Field logbooks from these activities are presented in Reference 93. The “A” zone and “B” zone are separated by a clay layer (A/B) that ex ists at depths ranging from 11 feet to 32 feet bls across the SEC and General Dynamics properties; however, the A/B clay layer is absent in certain areas of both properties (Ref. 8, p. 2-4, Figure 2-3). Soil and direct push ground water samples were collected during the investigation and analyzed for eight haloge nated compounds (Ref. 46, p. 1; 58). TCE and its degradation products were detected in subsurface so il samples collected from the western section of the General Dynamics property (Ref. 46, Table 1, Figure 1; Ref. 52. p. 24; 65).

In November 2003, URS conducted a su pplemental site investigation at the General Dynamics and SEC properties (Ref. 73, pp. Cover-1, 1-1). URS investigat ed the septic tanks in the areas west of Buildings 1 and 2 on the General Dynamics property (Ref. 73, p. 2-1).

In 2005, URS, on behalf of GAFRI , conducted preliminary site characterization activities at the SEC and General Dynamics properties. Activities included the co llection of soil samples, direct push ground water sampling, monitoring well network installation and sampling, as well as septic tank sampling (Refs. 54; 57; 75; 80; 82; 90). All samples were analyzed for chlo rinated solvents (Ref. 49, pp. 1 through 4; 66; 81; 83; 84; 85; 86; 91). A soil sample was collected in th e vicinity of the former vapor degreaser at a depth of 3 feet bls on the General Dynamics property (Refs. 16, pp. 14, 15, Exhibit 1; 49, Figure 3). This sample contained 1,1-DCE at a concentration of 19.2 μg/kg. PCE was also detected in the soil sample, but at a concentration greater than the method detection limit but less than the reporting limit (Refs. 49, Table 1; 77, p. 15). Ground water sampled from a direct-pus h sampling location underlying and downgradient of the contaminated soil contained a significant increas e of 1,1-DCE (greater than 3 times background) (See Section 3.1, Likelihood of Release, of this HRS documentation record).

In 2007, MACTEC conducted a site inspection (SI) at the General Dynamics property on behalf of FDEP. SI activities included the collection of soil and gr ound water samples from eight areas of concern to identify possible source areas on the General Dynamics property (Ref. 10, pp. 19, 20, 21, 22). The samples were analyzed for VOCs and Resource Conservation and Recovery Act (RCRA) metals (Ref. 10, p. 20). Surface and subsurface soil samples collected in the vicinity of the paint and plating building contained cadmium, chromium, lead, and silver at elev ated concentrations (Refs. 3; 10, p. 53, Tables 7 and 9). Surface and subsurface soil samples did not contain site-related or ganic hazardous substances19 (Ref. 10, p. 52, Tables 6 and 8). One ground water sa mple collected in the vicinity of the paint and plating building contained chromium at 52 μg/L (Ref. 10, p. 51, Table 11).

Ground water samples were collected from direct push sample locations and newly installed micro wells located near Source 2 (DPGW03, MW-AOC-1, MW-AOC-A2) at depths ranging from 10 to 42 feet bls (Ref. 10, pp. 21, 22, 56, Tables 3 and 4). The sample s contained PCE, TCE, cis-1,2-DCE, 1,1-DCE, and vinyl chloride (Ref. 10, p. 56, Table 10). The concen trations of PCE, TCE, 1,1-DCE, and vinyl chloride detected in the samples exceeded th eir respective EPA MCLs (Refs. 10, p. 56, Table 10; 48, pp. 2, 4, 5). The greatest concentration of 1,1-DCE was detected at a depth of 20 to 24 feet bls with concentrations of 3,400 μg/L. The greatest concentration of TCE, 8.2 μg/L, was detected at a depth of 38 to 42 feet bls, and the greatest concentration of vinyl chloride, 8.5 μg/L, w as detected at a depth of 15 to 25 feet bls (Ref. 10, p. 56, Table 10).Source No: 2

20 Source Characterization 2.2 SOURCE CHARACTERIZATION

2.2.1 SOURCE IDENTIFICATION

Number of source : 2

Name of source : Contaminated soil in the southeastern corner of Building 3

Source Type : Contaminated soil

Description and Location of Source (with reference to a map of site):

Source No. 2 is contaminated soil containing 1,1-DCE located beneath the southeastern corner of Building 3 (see Figure 2 of this HRS documentation r ecord). In 2005, URS collected a subsurface soil sample (SB-038-03) in the southeast corner of Build ing 3 (Ref. 80, p. 29; 49, Figure 3). The sample contained 1,1-DCE at an elevated concentration (Ref . 77, p. 15) (see Table 3 of this HRS documentation record). 1,1-DCE is a breakdown product of 1,1,1-TC A and TCE (Ref. 52, p. 24, B4-63). Solvents such as 1,1,1-TCA and TCE are indicated to have been used at the General Dynamics facility (Ref. 41, pp. 11, 12, 13; 88, pp. 7 through 11, 14, 15). Solvents were stored in an above ground storage tank located outside Building 3, and used in a vapor degreaser located near Source No. 2 (Ref. 41, pp. 11, 12, 13; 88, pp. 7 through 11, 14, 15). Additionally, an underground storage tank is located near Source 2 (Ref. 8, pp. 1-4, 2-2, Figure 1-2)Source No: 2

21 Source Characterization 2.2.2 HAZARDOUS SUBSTANCES ASSOCIATED WITH THE SOURCE

The subsurface soil samples listed in Table 3 were collected by URS during the June through September 2005 RI (Refs. 8, p. 2-5; 50, p. 44; 75, pp. 13, 20; 76, p. 46; 77, p. 34; 80, pp. 27, 29; 92, p. 43). The subsurface soil samples were collected at 3 feet bls. Subsurface soil samples, SB-006-3, SB-017-3, and SB-037-3, were collected from the General Dynamics a nd SEC properties at the same depth (3 feet bls) and were used to establish background concentrations (Refs. 49, Figure 3; 75, pp. 13, 20; 80, pp. 27, 29). The contaminated subsurface soil sample, SB-038-03 , was collected in the southeastern corner of Building 3 at a depth of 3 feet below the building floo r. The sample was collected inside the building by coring through the concrete using a direct push rig. (Ref s. 16, pp. 14, 15, Exhibit 1; 49, Figure 3; 80, pp. 29, 30). The background subsurface soil samples and contaminated subsurface soil samples were collected from the same soil type (urb an land, 0 to 12 percent slopes), at the same depth, during the same sampling event, and in accordance with the same sampli ng procedures (Refs. 7; 8, p. 2-5; 49, Figure 3; 55, pp. 167, 168, 169; 74, Appendix E, p. E-30; 75, pp. 13, 20; 80, pp. 27, 29; 87, Section 12).

The subsurface soil samples were collected in accord ance with the EPA Region 4, Science and Ecosystem Support Division (SESD) Environmental Investigati ons Standard Operating Procedures and Quality Assurance Manual (EISOPQAM) (Refs. 7; 8, pp. 2-5; 74, Appendix E, p. E-30; 87, Section 12). The samples were analyzed for VOHs (volatile or ganic hydrocarbons) usi ng EPA SW846 Method 8260B (Refs. 8, p. 2-5; 50, p. 7; 59, p. 1, FOUR-15; 76, p. 13; 77, p. 15; 92, p. 18). Data validation was conducted by URS and the data va lidation reports are contained in Reference 51. The URS data validation reports were reviewed to ensure that the National Functional Guidelines were followed.

Analytical data sheets and chain of custody records are contained in References 50, 76, 77, and 92. Logbook notes are provided in Refere nces 75 and 80. The locations of the subsurface soil samples listed in Table 3 are provided in Figure 3 of Reference 49.

TABLE 3: Analytical Results for Source No. 2 – June through September 2005

Sample ID

/Station ID Hazardous

Substance Hazardous

Substance

Concentration MDL References

Background Subsurface Soil Sample

SB-006-3 1,1-DCE 4.5U μg/kg 4.5 μg/kg 28, pp. 1-3; 50, pp. 7, 44; 51, pp. 57 through 61; 75, p. 13

SB-017-3 1,1-DCE 4.7U μg/kg 4.7 μg/kg 28, pp. 1-3; 51, pp. 62 through 66; 75, p. 20; 76, pp. 13, 46

SB-037-3 1,1-DCE 3.2U μg/kg 3.2 μg/kg 28, pp. 1-3; 51, pp. 47 through 51; 80, p. 27; 92, pp. 18, 43

Contaminated Subsurface Soil Sample

SB-038-03 1,1-DCE 19.2 μg/kg 2.5 μg/kg 28, pp. 1-3; 77, pp. 15, 34; 51, pp. 2 through 6; 80, p. 29

Notes:

1,1-DCE 1,1-Dichloroethlyene

ID Identification number μg/kg Microgram per kilogram

MDL Method detection limit SB Subsurface soil sample U Material not detected at or above reporting limitSource No: 2

22 Source Characterization 2.2.3 HAZARDOUS SUBSTANCES AVAILABLE TO A PATHWAY

The subsurface soil sample collected from Source No. 2 contained an elevated concentration of 1,1-DCE (Refs. 49, Figure 3; 77, pp. 15, 34) (also see Table 5 of this HRS documentation record). Source No. 2 consists of an area of contaminated soil located in the southeastern portion of Building 3 on the General Dynamics property (Ref. 16, pp. 14, 15, Exhibit 1). An alytical results for ground water collected in the vicinity of Source No. 2 indicate that a release of hazardous substances has occurred to the ground water migration pathway as documented in Section 3.0 of this HRS documentation record. During the 2005 RI, a liner was not observed during sampling activities (Ref. 56). Therefore, a containment factor value of 10 was assigned for the ground water migration pathway (Ref. 1, Section 3.1.2.1, Table 3-2).

TABLE 4: Containment Factors for Source No. 2

Containment Description Containment

Factor Value References

Gas release to air NS NA

Particulate release to air NS NA

Release to ground water: No liner 10 1, Section 3.1.2.1, Table 3-2; 56

Release via overland migration and/or flood NS NA

Notes:

NA Not applicable

NS Not scoredSource No: 2

23 Source Characterization 2.4.2.1 HAZARDOUS WASTE QUANTITY

2.4.2.1.1 Hazardous Constituent Quantity

The information available is not sufficient to evalua te Tier A, hazardous constituent quantity, as required by Reference 1, Section 2.4.2.1.1.

Hazardous Constituent Quantity Assigned Value: NS

2.4.2.1.2 Hazardous Wastestream Quantity

The information available is not sufficient to evalua te Tier B, hazardous wastestream quantity, as required by Reference 1, Section 2.4.2.1.2.

Hazardous Wastestream Quantity Assigned Value: NS

2.4.2.1.3 Volume

The information available is not sufficient to evalua te Tier C, hazardous volume quantity, as required by Reference 1, Section 2.4.2.1.3.

Volume Assigned Value: 0

2.4.2.1.4 Area

Only one sample was collected from Source No. 2 in the vicinity of the former vapor degreaser (Refs. 16, pp. 14, 15, Exhibit 1; 49, Figure 3). As a result, it is not known whether contamination in Source No. 2 is continuous throughout and the extent of contamina tion is not defined. The area of Source No. 2 is undetermined, but greater than zero (Ref. 1, Section 2.4.2.1.4).

Sum (ft 2 ): >0 Equation for Assigning Value (Table 2-5): Area (A)/34,000 Area Assigned Value: >0

2.4.2.1.5 Source Hazardous Waste Quantity Value

The source hazardous waste quantity (HWQ) value for Source No. 2 is assigned a source HWQ value of greater than zero, but unknown (Ref. 1, Sec. 2.4.2.1.5).

Source HWQ Value: >024 Source Characterization SUMMARY OF SOURCE DESCRIPTIONS

TABLE 5: Summary of Source Descriptions

Containment Factor Value by Pathway

Air

Source

No. Source

Hazardous

Waste Quantity

Value Source

Hazardous

Constituent

Quantity Complete?

(Yes/No) Ground

Water (Ref. 1, Table 3-2) Surface

Water

Overland/

Flood (Ref. 1, Table 4-2) Gas (Ref. 1, Table 6-3) Particulate (Ref. 1, Table 6-9)

2 >0 No 10 NS NS NS

Notes:

> Greater than

NS Not scored

Description of Other Possible Sources

During the 2007 SI conducted by MACTEC, surface and subsurface soil samples were collected from various locations throughout the property surrounding the paint and plating building located in the northeastern portion of the property (Refs. 3; 10, pp. 1, 3, 51, 52, 53, Tables 3, 7, and 9) (see Figure 2 of this HRS documentation record). Sediment samples have also been collected from the drainage ditch that runs between the General Dynamics and SEC proper ties and were found to contain TCE and DCE (Ref. 8, Tables 4-1 and 4-2, Figure 2-2). Surface and subs urface soil samples collected during the SI contained cadmium, chromium, lead, and silver at elevated concentrations (Ref. 10, pp. 52, 53, Tables 7 and 9). One ground water sample collected in the vicinity of the paint and plating building contained chromium at 52 μg/L (Ref. 10, p. 51, Table 11).25 GW-Likelihood of Release 3.0 GROUND WATER MIGRATION PATHWAY

3.0.1 GENERAL CONSIDERATIONS

Ground Water Migration Pathway Description

The General Dynamics property is located in the western section of Seminole County on the Florida Platform section of the Atlantic Coastal Plain province (Ref s. 4, p. 3; 10, p. 48; 67, pp. 2, 3; 69, p. 4). The topography in Seminole County is divided into two types: a flat lowland and hilly uplands (Refs. 68, p. 6; 70, pp. 6, 7). Elevation at the General Dynamics property is about 35 feet above sea level (asl) (see Figure 1 of this HRS documentation record) (Ref. 30) . The General Dynamics property is underlain in descending stratigraphic order by undifferentiated deposits of the Holo cene, Pleistocene, and Pliocene age; the Hawthorn Group of the Miocene age; the Ocala Limestone, Avon Park Formation, and Oldsmar Formation of the Eocene age; and the Cedar Keys Fo rmation of the Paleocene age (Ref. 68, pp. 10, 13).

The undifferentiated deposits of Pliocene to Holocene ag e consist of alluvium, freshwater marl, peats and muds in stream and lake bottoms, quartz, sand, she ll fragments and sandy clay. The deposits range from 0 to 150 feet bls in the vicinity of the General Dynamics property (Ref. 68, p. 13).

Underlying the undifferentiated depos its is the Hawthorn Group. The Hawthorn Group consists of beds of blue to gray, calcareous clay, altering with beds of cream to gray sandy limestone containing numerous grains of black to cream phosphate rack and fragments of chert. The deposits range from 0 to 200 feet in thickness (Refs. 68, p. 13; 70, p. 15).

The Ocala Limestone underlies the Hawthorn Group and is characterized by white-cream to tan-gray soft to hard, granular, porous foraminiferal marine limestones (Refs. 68, p. 13; 70, p. 15). The Ocala Limestone is about 0 to 200 feet thick and overlies the Avon Park Formation, whic h consists of light to brown, soft to hard, porous to dense, granular to chalky, fossiliferous limestone and brown, crystalline dolomite (Refs. 68, p. 13; 70, pp. 13, 14). The Avon Pa rk Formation is about 600 to 1,600 feet thick. Underlying the Avon Park Formation is the Oldsmar Formation which has a thickness of 300 to 1,350

feet. This formation consists of alternating beds of light brown to white, chalky, porous, fossiliferous limestone and porous crystalline dolomite. The Avon Pa rk Formation is underlain by the Cedar Keys Formation, which consists of dolom ite with anhydrite and gypsum and some limestone. The Cedar Keys formation is about 500 to 2,200 feet thick (Ref. 68, p. 13).

Ground water in the Seminole County, Florida area exists in two distinct units: the surficial aquifer and the Floridan aquifer. These aquifers are separate d by a discontinuous inte rmediate confining unit (Hawthorn Group). The surficial aquifer has limited u se due to low yields to wells and the potential for contamination. Water withdrawn from the surficial aqui fer is used mainly for lawn irrigation (Refs. 8, Figure 4-40; 29; 68, pp. 2, 13; 71, p. 32). The Florid an aquifer system is the principal source of ground

water in east-central Florida and is divided into tw o aquifers of relatively high permeability, the Upper Floridan and the Lower Floridan aquifers. These a quifers are separated by a less permeable unit that restricts the downward movement of water (Ref. 68, p. 19).

The surficial aquifer consists of undifferentiated sediments of the Holocene, Pleistocene, and Pliocene ages; the intermediate confining unit consists of pa rt of the Hawthorn Group; and the Floridan aquifer consists of portions of the Hawthorn Group, Ocal a Limestone, the Avon Park Formation, the Oldsmar Formation, and the upper part of the Cedar Keys Fo rmation (Ref. 68, pp. 13, 19). In Seminole County, the surficial aquifer is separated from the Floridan aquifer by the confining bed of the Hawthorn Group; however, the Hawthorn Group is not continuous; and is not present directly north (about 240 feet) of the General Dynamics property (Refs. 8, Figure 4-40; 29; 71, p. 32).

The surficial aquifer is the upper most water bearing unit in Seminole County. The system is unconfined and consists mainly of lenses of fine to medium qua rtz sand with varying amounts of shell and clay. The deposits are discontinuous and their lithology and texture can vary over short distances. The top of the26 GW-Likelihood of Release surficial aquifer is defined by the water table (Ref. 68, p. 14). The base of the surficial aquifer system is characterized by the first persistent beds of Mio cene or Pliocene age containing a significant increase in clay or silt. The altitude at the base of the surficial aquifer system ranges from about 75 feet asl to more than 75 feet below sea level in Seminole County (Ref. 68, p. 16).

Underlying the surficial aquifer is the intermed iate confining unit (Hawthorn Group) containing interbedded quartz, locally highly phosphatic clay, s ilt, sand, and limestone (Ref. 68, pp. 13, 18). The thickness of the confining unit is variable due to past erosional processes and sinkhole formation. In Seminole County, the thickness of the Hawthorne Group ranges from 25 to greater than 100 feet (Ref. 68, p. 18). However, the Hawthorn Group is not continuous in the vicinity of the General Dynamics property. Specifically, the group is absent directly north (about 240 feet) of Source No. 2 on the General Dynamics property; therefore, the surficial and Upper Floridan aquifers are interconnected (Refs. 8, Figure 4-40; 29; 71, p. 32).

The Upper Floridan aquifer is composed of the O cala Limestone and the dolomitic limestones of the upper one-third of the Avon Park Formation (Ref. 68, p. 19). In the vicinity of the General Dynamics property, the top of the Upper Floridan aquifer is encountered at about 50 feet below sea level (about 85 feet bls) (Refs. 30; 68, p. 22). However, accordi ng to the U.S. Geological Survey (USGS) well datacollection sites, the depths of wells installed in the Upper Floridan aquifer in Seminole County range from 90 to 925 feet bls. (Refs. 9, Plates 28 and 29; 30; 68, pp.102 through 107). Also, the depths of municipal wells installed in the Upper Floridan aquifer in Se minole County range from 162 to 925 feet bls (Refs. 31, pp. 1, 2; 32, p.1; 33, pp. 1, 2; 34; 35, pp. 1, 22; 36, p.1; 37, p. 1; 61; 62, p. 2; 63; 94; 97) (see Table 17 of this HRS documentation record). Well logs of m onitoring wells installed in the Upper Floridan aquifer on the SEC and General Dynamics properties display wate r levels indicating that ground water flow is to the north-northeast (Ref. 8, p. 3-4, Figure 3-10).

Ground water flow in the Upper Floridan aquifer sy stem is mostly through porous limestone, and is enhanced by networks of small fractures or solution openings that occur along joints or bedding planes. In some areas, flow may be through large cavernous features of paleokarst, resulting in a dual-porosity flow system (Ref. 68, pp. 19, 21, 23). In addition, Florida Geological Survey well logs to the north and south of the General Dynamics property indicate pin point voids in the limestone units of the Upper Floridan aquifer. Karstic ground water flow occurs in the Upper Floridan aquifer (Refs. 64, pp. 4, 14; 78).

Recharge in the Upper Floridan aquifer is by downward leakage from the surficial aquifer system, through breaches in the intermediate confining unit caused by sinkholes or where the confining unit is thin or missing, by lateral inflow, and through draina ge wells (Ref. 68, p. 29). The highest rates of recharge from the surficial aquifer to the Upper Fl oridan aquifer occur in western Seminole County, which is characterized by karstic sand ridges with re latively deep water tables or an intermediate confining unit that is relatively thin (Ref. 68, p. 29). Karst terrain is also exhibited in Longwood, Florida by numerous sinkholes of various sizes (Refs. 78; 95, pp. 1 through 6).

The middle semiconfining unit separates the Upper and Lower Floridan aquifers and consists of soft micritic limestone and fine-grained dol omitic limestone, both of low porosity (Refs. 9, p. B56; 68, p. 23). The middle semiconfining unit is the leakiest confinin g unit in the Floridan aquifer system (Ref. 9, pp. B3, B56). In Seminole County the middle semiconfining unit ranges in thickness from about 400 to 550 feet (Refs. 9, p. B57; 68, p. 23).

The Lower Floridan aquifer includes the lower one-t hird of the Avon Park Formation and all of the Oldsmar Formation. The aquifer is very productive and is composed of altering beds of limestone and fractured dolomite (Ref. 68, p. 23). The top of the Lo wer Floridan aquifer is encountered at about 900 to 1,000 feet below sea level (which corresponds to about 93 5 to 1,035 feet bls at the site) (Refs. 30; 98, pp. 20, 21; 99, pp. 1, 5, 6). The Lower Floridan aquifer is about 910 to 1,180 feet thick. Therefore, the base of the Lower Floridan Aquifer is estimated to be between 1,810 and 2,180 feet below sea level (which corresponds to about 1,845 to 2,215 feet bls at the site) (Refs. 9, Plates 31 and 33; 30; 98, pp. 20 through27 GW-Likelihood of Release 23). According to USGS well data-collection sites, th e depths of wells installed in the Lower Floridan aquifer in Seminole County range from 984 to 1, 506 feet bls (Ref. 68, pp. 102 through 107).

Previous investigations at the General Dynamics and SEC properties divide the surficial aquifer into two water bearing zones, A-zone and B- zone, and refer to the Upper Floridan aquifer as the C-zone. The Azone (upper surficial aquifer) and B-zone (lower surficial aquifer), are separated by a discontinuous clay layer (A/B clay) (Ref. 8, pp. 3-3, 3-4, Figure 2-3). The A/B clay layer ranges in depth from 13.5 bls to 32 feet bls across the General Dynamics property and is absent in the northwestern portion of the property (Ref. 8, p. 2-4, Figure 2-3, Appendix C, pp. 27 throu gh 49). The ground water flow direction in the A and B zones is north to northeast across the General Dyna mics property (Refs. 8, Figures 3-6 and 3-7; 10, p. 57).

Three horizontal wells were installed in the upper su rficial aquifer along the north boundary of the SEC property to capture impacted shallow ground water and prevent the movement of the shallow volatile organic hydrocarbon (VOH) plume to the north (Ref. 8, p. 4-8; 74, Appendix H, Figure 2, Figure 4). One recovery well was installed in the lower surficial a quifer to provide some hydraulic control, recover contaminants from the B-zone (lower surficial aqui fer), and to create additional upward pressure to further reduce the possibility of vertical migration of contaminants into the Floridan aquifer (Ref. 8, pp. 1- 9, 4-8). The operation of this system does not alter the general northerly movement of ground water in the surficial aquifer (Ref. 8, Figs. 3-6, 3-7, Appendi x D, p. D-105; 10, Fig. 10; 74, Appendix H, Figs. 4, 5).

SUMMARY OF AQUIFERS BEING EVALUATED

TABLE 6: Summary of Aquifers Being Evaluated

Aquifer Name Is Aquifer

Interconnected with Upper Aquifer within 2

Miles? (Yes/No/NA) Is Aquifer

Continuous within

4-mile TDL?

(Yes/No) Is Aquifer

Karst? (Yes/No) References

Surficial Aquifer NA Yes No 78, p. 3

Upper Floridan Aquifer Yes Yes Yes 29; 78, p. 1

Notes:

NA Not applicable TDL Target distance limit28 GW-Likelihood of Release 3.1 LIKELIHOOD OF RELEASE

3.1.1 OBSERVED RELEASE

Aquifer Being Evaluated: Interconnected Surficial and Upper Floridan Aquifer

- Hazardous Substance in Release: 1,1-DCE

Chemical Analysis

Analysis of ground water underlying and downgradient of Source No. 2 shows a significant increase of 1,1-DCE (greater than 3 times) over background le vel (see Table 12 and 14 of this HRS documentation record).

Background Samples

Direct push ground water samples collected from direct push locations 23 and 26 (DPGW-23 and DPGW26) were collected on the northeastern and south centr al portion of the SEC property. These locations are upgradient of Source No. 2 and ground water underlying Source No. 2 (Ref. 8, Figures 3-6 and 3-7) (see Figure 2 of this HRS documentation record). Ther efore, ground water samples collected from DPGW-23 and DPGW-26 are used to represent background concentr ations for the observed release to the surficial aquifer underlying and downgradient of Source No. 2 at the General Dynamics property (Refs. 8, Figures 4-30 and 4-32; 72, p. 74; 75, pp. 55, 56). Backgroun d direct push ground water samples listed in Table 11 were collected at 22 feet bls and are compared to downgradient direct push ground water samples collected at corresponding depths (Ref. 8, Figures 4-30 and 4-32) (see Tables 11 and 13 of this HRS documentation record).

The direct push ground water samples were collected using a truck-mounted direct push rig and smaller track mounted direct push rig to advance stainless steel rods using hydraulic pressure and a hammer technique (Ref. 8, p. 2-7). The background dir ect push ground water samples were collected in accordance with the EPA Region 4 SESD EISOPQAM, dated November 2001 (Refs. 7; 74, Appendix E, p. E-29; 87, Section 7).

The locations of the direct push background ground wa ter samples are provided in Table 11 and depicted in Reference 8, Figures 4-29 through 4-32. Chain of custody records are provided in Reference 72, pp. 74, 76. Logbook notes are contained in Reference 75.

The background direct push and downgradient direct push ground water samples were collected from surficial aquifer wells with similar construction details, at similar depths, during the same sampling event, and in accordance with the same sampling procedures (Ref s. 7; 8, p. 2-7; 72, pp. 74, 76; 74, Appendix E, p. E-29; 77, p. 34; 80, p. 29; 87, Section 7) (see Ta bles 11 and 13 of this HRS documentation record).

TABLE 11: Background for June through September 2005

Sample ID Depth

(feet bls) Screened Interval
(feet bls) Date Sampled Location References

Background Samples for Ground Water Underl ying and Downgradient of Source No. 2

Direct Push Ground Water Sample Collected at 22 Feet bls

DPGW-23(22 ′ ) 22 NA 6/21/2005 Northeastern portion of SEC property 8, Figure 4-30; 75, pp. 55, 56; 72, p. 76

DPGW-26(22 ′ ) 22 NA 6/21/2005 South central portion of SEC property 8, Figure 4-30; 72, p. 7429 GW-Likelihood of Release Notes:

bls Below land surface DP Direct push

GW Ground water

ID Identification NA Not applicable

No. Number

′ Feet (#) Depth of direct push ground water sample in feet30 GW-Likelihood of Release Background Level

The ground water samples listed in Table 12 were collected by URS during the 2005 RI (Refs. 8, Figures 4-30; 72, pp. 74, 76; 75, pp. 55, 56).

These direct push samples were analyzed for VOHs using EPA SW846 Method 8260B (Refs. 8, pp. 4-12; 59, p. 1, FOUR-15; 72, pp. 33, 65). As seen in Table 12 below, 9.2 μg/L was the highest background concentration of 1,1-DCE, and is used as the background level for this evaluation.

Data validation was conducted by URS and the data validation reports are contained in Reference 51. The data validation reports were reviewed to en sure that the National Functional Guidelines were followed (Ref. 28, pp. 1, 2, 3). Method detection lim its, reporting limits, and anal ytical data sheets for the background ground water samples are contained in Reference 72.

TABLE 12: Analytical Results for June through September 2005 RI

Sample ID Hazardous

Substance Concentration RL References

Background Samples For Ground Water Underl ying and Downgradient of Source No. 2

Direct Push Ground Water Sample Collected at 22 Feet bls

DPGW-23(22 ′ ) 1,1-DCE 9.2 μg/L 0.50 μg/L 28, p. 1; 51, pp. 7 through 11; 72, p. 33

DPGW-26(22 ′ ) 1,1-DCE 0.50U μg/L 0.50 μg/L 28, p. 1; 51, pp. 7 through 11; 72, p. 65

Notes:

DCE Dichloroethylene DP Direct push

ID Identification number

GW Ground water

MDL Method detection limit μg/L Microgram per liter

No. Number RI Remedial Investigation RL Reporting limit U Analyte was not detected at or above the detection limit

′ Feet (#) Depth of direct push ground water sample in feet31 GW-Likelihood of Release Contaminated Sample

The contaminated direct push samples listed in Tabl e 13 were collected from direct push borings during the 2005 RI conducted by URS (Refs. 8, pp. 2-7). The contaminated ground water sample was collected from ground water underlying and downgradient of Source No. 2 (Refs. 8, pp. 4-12, Figures 4-29 through 4-32; 77, p. 34; 80, p. 29) (see Figure 2 of this HRS documentation record).

The contaminated ground water sample and its co rresponding depth is provided in Table 13. The contaminated ground water sample underlying and do wngradient of Source No. 2 was compared to upgradient ground water samples at corresponding dept hs (Ref. 8, Figures 4-29 through 4-32) (see Tables 11 and 13 of the HRS documentation record).

The direct push ground water samples were collected using a truck-mounted direct push rig and smaller track mounted direct push rig to advance stainless steel rods using hydraulic pressure and a hammer technique (Ref. 8, p. 2-7).

The contaminated ground water sample was colle cted in accordance with the EPA Region 4 SESD EISOPQAM, dated November 2001 (Refs. 7; 74, Appendix E, p. E-29; 87, Section 7). The location of the ground water sample listed in Table 13 is depicted on Figures 4-30 in Reference 8. Chain of custody records are provided in References 72 and 77. Lo gbook notes are provided in Reference 80.

TABLE 13: June through September 2005 RI

Sample ID Depth

(feet bls) Screened Interval
(feet bls) Date Sampled Location References

Ground Water Underlying or Downgradient of Source No. 2

Direct Push Ground Water Samples Collected at 22 Feet bls

DPGW-34(22 ′ ) 22 NA 9/16/2005 Southeastern Corner of Building No. 3 on General Dynamics

property 3; 8, Figure 4-30; 77, p. 34; 80, p. 29

Notes:

bls Below land surface DP Direct push

GW Ground water

ID Identification NA Not applicable

No. Number

′ Feet (#) Depth of direct push ground water sample in feet32 GW-Likelihood of Release Contaminated Concentration

The direct push ground water sample listed in Table 14 was collected from the General Dynamics property during the June through September 2005 RI conducted by URS (Refs. 8, pp. 4-12, Figures 4-29 through 4-32; 72, p. 75; 77, p. 34; 80, p. 29).

The direct push sample presented in Table 14 w as analyzed for VOH analysis using EPA SW846 Method 8260B (Refs. 8, p. 4-12; 59, p. 1, FOUR-15; 77, pp. 9, 10). Data validati on was conducted by URS and the data validation reports are contained in Reference 51. The URS data validation reports were reviewed

to ensure that the National Functional Guidelin es were followed (Ref. 28, pp. 1, 2, 3).

The method detection limits and reporting limits are cont ained on the analytical data sheets in Reference

77.

TABLE 14: Analytical Results for June through September 2005 RI

Sample ID Hazardous

Substance Concentration RL References

Ground Water Underlying and Downgradient of Source No. 2

Direct Push Ground Water Samples Collected at 22 Feet bls

DPGW-34(22 ′ ) 1,1-DCE 26,500 a μg/L 500 μg/L 28, pp. 1-3; 51, pp. 2 through 6; 77, pp. 9, 10

Notes:

a Result is from Run# 2 DCE Dichloroethylene DP Direct push μg/L Microgram per liter

MDL Method detection limit RL Reporting limit

′ Feet (#) Depth of direct push ground water sample in feet33 GW-Likelihood of Release Attribution

The significant increase of 1,1-DCE can be attributed to the General Dynamics Longwood site. 1,1-DCE is associated with Source No. 2, and a significant increase of 1,1-DCE is detected in ground water underlying and downgradient of Source No. 2 (see sec tions 2.2.2 Hazardous Subs tances Associated with

the Source and 3.1.1 Observed Release of this HRS documentation record). Additionally, upgradient background concentrations of 1,1-DCE indicate that releases from the SEC SAA site did not contribute significantly to the increase in the concentration of 1,1-DCE in the General Dynamics Longwood site observed release sample (see section 3.1.1 Observe d Release of this HRS documentation record).

According to depositions of former General Dy namics’ employees, General Dynamics (and its predecessors) manufactured printed circuit boards (Refs. 10, pp. 3, 4; 16, pp. 6, 7). Gould Publications purchased the property in 1993 and conducted printi ng and publication assembly operations. Currently, the property is used for wholesaling and warehouse activiti es (Refs. 10, p. 3; 18). Solvents such as 1,1,1- TCA and TCE (whose degradation products include 1,1- DCE) are indicated to have been used at the General Dynamics facility (Ref. 41, pp. 11, 12, 13; 52, p. 24, B4-63; 88, pp. 7 through 11, 14, 15). Solvents were stored in an above ground storage tank located outside Building 3, and used in a vapor degreaser located near Source No. 2 (Ref. 41, pp. 11, 12, 13; 88, pp. 7 through 11, 14, 15).

The adjacent SEC facility manufactured film capacitors on the property from 1959 to 1992. From about 1959 to December 1964, a portion of the SEC property was owned by Dearborn. Both SEC and Dearborn manufactured film capacitors at the SEC property. Film capacitors were assembled, soldered, impregnated with wax mineral oil or silicon oil in a pressurized chamber, and then cleaned in a vapor degreaser (Ref. 26, p. 3). The chemicals TCA and TCE were used as cleaning agents in the vapor degreaser, and contamination has been documented in SEC sources and ground water in the surficial and Floridan aquifers underlying the SEC property (Refs. 5, pp. 15, 18; 8, p. 1-5; 22, p. 3; 60). In January 1986 and December 1987, the SEC property entered into a State of Florida Consent Order that was approved and monitored by FDEP. Site assessments ha ve been conducted at the SEC property for over 20 years and have included numerous investigations. In 2003, the lead agency for cleanup activities was transferred to EPA (Refs. 8, p. ES-1). The AOC si gned and approved by EPA in June 2004 also included the General Dynamics property (Refs. 8, p. 1-1, Figure 1-4; 26, p. 3; 60).

In 2005, URS conducted an RI at the SEC property. During the 2005 RI, 1,1-DCE (a degradation product of TCE and 1,1,1-TCA) was detected in a subsurf ace soil sample (Source No. 2) as well as ground water on the General Dynamics property. (sample DPGW-34(22’) (Refs. 8, Figure 4-30; 49, Figure 3; 52, p. 24, B4-63; 77, p. 15) (see Figure 2 of the HRS documenta tion record). Due to this finding, EPA removed the eastern portion of the General Dynamics property fr om the AOC (Ref. 8, pp. 1-1, 1-2).

Although the SEC SAA site located hydraulically upgr adient (south of) of the General Dynamics property is a known source of ground water contamination (Ref. 10, p. 4, 5), upgradient background concentrations of 1,1-DCE indicate that releases from the SEC site di d not contribute significantly to the increase of the concentration of 1,1-DCE in the General Dynamics Longwood site observed release sample (see section 3.1.1 Observed Release of this HRS documentation record) Additionally, analytical results from 1989 to2005 indicate that the concentration of 1,1-DCE detected in direct push ground water sample, DPGW34(22 ′ ), collected from ground water underlying Source No. 2 on the General Dynamics property contained the highest concentration of 1,1- DCE (26,500 μg/L) detected during ground water investigations conducted at the General Dynamics a nd SEC properties (Refs. 8, Figures 4-29 through 4- 32, 4-38, 4-39; 51, pp. 1 through 6; 77, p. 9; 96, Tables 1 through 4).

To highlight this, the analytical and sampling data from 1988 to 2006 available in the references to the

HRS documentation record have been reviewed to ch aracterize the contamination levels in the ground water hydraulically upgradient of the release samp le (see references cited on Figure 4 of this HRS documentation record); these data include historical results for monitoring well samples from the A-zone and B-zone of the surficial aquifer and direct push ground water samples. The sample locations selected for review are from the area depicted in Figure 4 of this HRS documentation record, which presents the34 GW-Likelihood of Release extent of the area considered hydraulically upgrad ient of the release samp le, including approximate locations of the reviewed upgradient samples. As discussed in section 3.0.1 General Considerations, Ground Water Migration Pathway Description, of this HRS documentation record, a generally northern flow direction of ground water has been documented fro m various investigations at the site. The westernmost extent of the upgradient area in Figure 4 was sel ected to be as inclusive as reasonably possible based upon analysis of the ground water flow directi on maps provided in the references to the HRS documentation record (see references cited on Figure 4 of this HRS documentation record). No upgradient occurrence of 1,1-DCE or possible parent compound were found at levels sufficient to explain the concentration found in observed release sample DPGW-34(22’).

In addition to SEC, another source of potential contamination may exist in the area. Continental Circuits, Inc. is located about 1.5 miles northwest of the General Dynamics property (Ref. 12, pp. 1, 2, 3, 4, 9, 10). However, Continental Circuits, Inc. is located hy draulically side gradient to the General Dynamics property and is not expected to impact contaminati on or releases at the General Dynamics property (Refs. 8, Figures 3-6, 3-7 and 3-10; 12, pp. 9, 10).

Hazardous Substance in the Release

1,1-dichloroethylene

Ground Water Observed Release Factor Value: 550.0035 GW-Likelihood of Release 3.1.2 POTENTIAL TO RELEASE

Potential to release was not evaluated for the uppe r and lower surficial aquifers because an observed release has been documented (see Section 3.1.1 of this HRS documentation record). The Hawthorne Formation, which underlies the surficial aquifer, is no t continuous in the vicinity of the General Dynamics property. Specifically, the formation is absent about 240 feet north of the General Dynamics property; therefore, the surficial and upper Floridan aquifers ar e interconnected (Refs. 8, Figure 4-40; 29; 68, p. 18; 71, p. 32).

3.2 WASTE CHARACTERISTICS

3.2.1 TOXICITY/MOBILITY

The toxicity and mobility factor values for the hazardous substance detected in the source sample with a containment factor value of greater than 0 are su mmarized in Table 15. The combined toxicity and mobility factor value is assigned in accordance with Re ference 1, Section 3.2.1. The hazardous substance detected in the observed release to ground water is assi gned a mobility factor value of 1 (Ref. 1, Section 3.2.1.2).

TABLE 15: Ground Water Toxicity/Mobility

Hazardous

Substance Source

No. Toxicity Factor

Value Mobility
Factor Value Does Hazardous

Substance Meet

Observed

Release? (Yes/No) Toxicity/ Mobility (Table 3-9) Reference

1,1-DCE 2 100 1 A Yes 100 2, p. BI-5

Notes:

A Documented in the observed release to ground water. A mobility factor value of 1 is assigned (Ref. 1, Section 3.2.1.2).
DCE Dichloroethylene

No. Number

Toxicity/Mobility Factor Value: 10,000.00 (Reference 1, Table 3-9)36 GW-Waste Characteristics 3.2.2 HAZARDOUS WASTE QUANTITY

TABLE 16: Hazardous Waste Quantity

Source No. Source Type Source Hazardous Waste Quantity

2 Contaminated soil Undetermined, but greater than zero

The hazardous constituent quantity for Source No.2 is not adequately determined. The HWQ is undetermined, but greater than zero. As specified in Reference 1, Section 2.4.2.2, a HWQ factor value of 10 was assigned.

Hazardous Waste Quantity Factor Value: 10 (Reference 1, Sec. 2.4.2.2)

3.2.3 WASTE CHARACTERISTICS FACTOR CATEGORY VALUE

The waste characteristics factor category value w as obtained by multiplying the toxicity/mobility and HWQ factor values, subject to a maximum product of 1 × 10 8 . Based on this product, a value was assigned in accordance with Reference 1, Table 2-7.

Toxicity/Mobility Factor Value: 100.00 Hazardous Waste Quantity Factor Value: 10

Toxicity/Mobility Factor Value × Hazardous Waste Quantity F actor Value: 1,000.00

Waste Characteristics Factor Category Value: 6 (Reference 1, Table 2-7)37 GW-Targets 3.3 TARGETS

Residents in the vicinity of the General Dynamics property are provided drinking water from one of seven municipal systems: Seminole County, Casselberry, Lake Mary, Longwood, Winter Springs, Sanford, and Sanlando Utilities (Ref. 30).

Seminole County operates three water treatment plants (WTP) served by 19 municipal wells, 9 of which are in two distribution systems within a 4-mile radi us of the General Dynamics property. The Greenwood Lakes WTP (five wells) and Country Club WTP (two wells) make up one distribution system and the Heathrow WTP (two wells) makes up the second distribution system. Of the nine wells, four are located within 1 to 2 miles (Greenwood Lakes and Country Cl ub WTPs), three are located within 2 to 3 miles (Greenwood Lakes WTP), and two (Heathrow WTP) ar e located within 3 to 4 miles of the General Dynamics property (Refs. 30; 31, pp. 1, 2, 3, 5, 7) . The depths of the Greenwood Lakes WTP wells range from 480 to 900 feet, the depths of the Country Club WTP wells are 350 feet, and the depths of the Heathrow WTP wells are 325 and 390 feet (Refs. 31, pp. 1, 2; 61). All wells obtain water from the Upper Floridan aquifer (Ref. 31, pp. 1, 2). Water from the Greenwood Lakes and Country Club WTPs is combined into one distribution system and is mixed in the distribution lines. These two WTPs collectively serve about 18,094 people (18,094 ÷ 7 we lls = 2,584.86 people served per well) (Ref. 31, pp. 1, 2). The second distribution system includes the Heathrow WTP along with three other WTPs. The Heathrow WTP operates five wells, two of which are located within 3-4 miles of the General Dynamics property (Ref. 30; 31, pp. 1, 2). The three other W TPs and their seven wells are not located within a 4- mile radius of the General Dynamics property. Wate r from the four WTPs is mixed in distribution lines and serves about 24,439 people collectively (24,439 people ÷ 12 wells = 2,036.58 people served per well). None of the Seminole County wells produces more than 40 percent of the total water supply in the distribution systems (Refs. 30; 31, pp. 1, 2). Wate r from the two distribution systems does not mix in the distribution lines to form one blended system (Ref. 31, p. 9).

The City of Casselberry maintains nine municipal wells and three (N-1, N-2, and N-3) are located within 2 to 3 miles of the General Dynamics property (Refs. 30; 36, pp. 1, 2, 3). Of these three wells, one well obtains water from the Lower Floridan aquifer a nd two wells obtain water from the Upper Floridan aquifer. The depths of the wells ra nge from 377 to 1,200 feet (Ref. 36, pp. 1, 2, 3). None of the City of Casselberry wells produce more than 40 percent of th e total water supply. The water from the wells can be mixed in distribution lines. The City of C asselberry collectively serves 54,800 people or 6,088.89 people per well (54,800 people ÷ 9 wells) (Ref. 36, p. 1).

The City of Lake Mary maintains five municipal wells located within 3 to 4 miles of the General Dynamics property (Refs. 30; 32, p. 1). None of th e Lake Mary wells produce more than 40 percent of the total water supply. All wells obtain water from th e Upper Floridan aquifer and the depths range from

500 to 695 feet. The water from all five wells is mixe d prior to distribution to customers. The City of Lake Mary wells collectively serve 13,496 people (13,496 ÷ 5 = 2,699.20 people served per well) (Ref. 32, pp. 1, 2; 62, pp. i, 1, 2).

The City of Longwood maintains five municipal wells; two of the wells are located within 1 to 2 miles

and 3 are located within 2 to 3 miles of the General Dynamics property (Refs. 30; 33, pp. 1, 4 through 9). None of the City of Longwood wells produce more than 40 percent of the total water supply. All wells obtain water from the Upper Floridan aquifer and the depths range from 300 to 500 feet. The water from all five wells is mixed prior to distribution to custom ers. The City of Longwood wells collectively serve 20,223 people (20,223 people ÷ 5 wells = 4,044.60 pe ople served per well) (Ref. 33, pp. 1 through 10).

The City of Sanford operates 19 municipal wells; six of the wells are located within 3 to 4 miles of the General Dynamics property (Refs. 30; 34, pp. 1, 2, 3). The wells located within the 4-mile radius of the General Dynamics property obtain water from the Uppe r Floridan aquifer and the depths range from 162 to 350 feet. None of the City of Sanford wells produce more than 40 percent of the total water supply. The water from all 19 wells is mixed prior to distri bution to customers. The City of Sanford wells38 GW-Targets collectively serve 61,975 people (61,975 people ÷ 19 we lls = 3,261.84 people served per well) (Refs. 34, pp. 1, 2, 3; 63, pp. 3, 5, 6).

The City of Winter Springs operates eight municipal we lls; four of the wells are located within a 4-mile radius of the General Dynamics property. The wells are distributed as follows: 0.25 to 0.5 mile, one well; 0.5 to 1 mile, 1 well; and 2 to 3 miles, two wells (R efs. 30; 37, p. i). None of the City of Winter Springs wells produce more than 40 percent of the tota l water supply. The depths of the wells range from 290 to 491 feet deep and obtain water from the Upper Fl oridan aquifer. The water from all eight wells is mixed in distribution lines. The City of Winter Springs wells collectively serve 35,983 people (35,983 people ÷ 8 wells = 4,497.88 people served per well) (Refs. 37, p. i, 1, 2; 94).

Sanlando Utilities maintains 11 municipal wells; six ar e located within 3 to 4 miles of the General Dynamics property (Refs. 30; 35, p. 1; 97). Well No . 8, located outside the 4-mile radius, supplies 50 percent of the total water supply (Ref. 35, p. 1). All wells obtain water from the Upper Floridan aquifer and the depths of the wells range from 420 to 925 f eet deep (Ref. 97). The water from all 11 wells is mixed prior to distribution to customers. Sanlando Utilities collectively serves 35,700 people (Refs. 35, pp. 1 through 8). Therefore, the amount of people served by Well No. 8 is 17,850 (35,700 ÷ 2) and the remaining 10 wells, which each contribute equally to the remaining 50 percent of the total water supply, serve 1,785 people served per well (17,850 ÷ 10) (Refs. 35, p. 1; 97).

The service areas for Sanlando Utilities, City of Longw ood, and City of Winter Springs were obtained from their respective contact person (Refs. 33, p. 1; 35, pp. 1, 2; 37, pp. 2, 3). The service areas for the City of Sanford, Seminole County, and the City of Lake Mary were obtained from the St. Johns River Management District Consumptive Use Permits 162, 8213 , and 8284, respectively (Refs. 38, p. 6; 39, pp. 7 through 10; 40, p. 6).

Municipal wells located within a 4-mile radius of the General Dynamics property provide drinking water to about 116,336.52 people. The pop ulation served by these wells per distance ring is distributed as follows: > 0 to 0.25 mile, 0 people; > 0.25 to 0.50 mile, 4,497.88 people; > 0.50 to 1 mile, 4,497.88 people; > 1 to 2 miles, 18,428.64 people; > 2 to 3 miles, 41,061.92 people; > 3 to 4 miles, 47,850.20 people (Refs. 30; 31, pp. 1 through 8; 32, pp. 1, 2; 33, pp. 1 through 8; 34; 35, pp. 1 through 8; 36, pp. 1, 2, 3; 37, pp. i through 11) (also see Table 17 of this HRS documentation record). All of the wells in the area are screened in the Upper Floridan aquifer at a maxi mum depth of 925 feet (Refs. 31, pp. 1, 2, 9; 32, p. 1; 33, pp. 1, 2; 34; 35, p. 1; 36, p. 1; 37, p. 1; 94; 97). Seminole County, Sanlando Utilities, and the cities of Lake Mary, Sanford, and Casselberry have wellhead protection areas (Refs. 31, p. 2; 32, p. 1; 33, p. 1; 34, p. 1; 35, p. 1; 36). Therefore, wellhead protection areas are located within the 4-mile radius of the source at General Dynamics (Ref. 30).39 GW-TargetsTABLE 17: Municipal Drinking Water Wells Within A 4-Mile Radius Of General DynamicsUpper Floridan AquiferDistanceRingMilesWater System NameNumberof WellsWell No. andDepth of Wells(feet bls)Level ICont.(Y/N)Level IICont.(Y/N)PotentialCont.(Y/N)PopulationServedReferences> 0.25 to 0.5City of Winter Springs1Well No. 3 – 491NNY4,497.8830; 37; pp. ithrough 11;94>0.5 to 1City of Winter Springs1Well No. 6 – 400NNY4,497.8830; 37; pp. ithrough 11;94> 1 to 2Seminole County(Greenwood Lakes andCountry Club WTPs)4Well No. 1 – 350Well No. 2 – 350Well No. 5 – 500Well No. 4 – 700NNY10,339.4430; 31, pp. 1through 8; 61> 1 to 2City of Longwood2Well No. 1 – 372Well No. 2 – 390NNY8,089.2030; 33, pp. 1through 10> 2 to 3Seminole County(Greenwood LakesWTP)3Well No. 1 – 480Well No. 2 – 900Well No. 3 – 607NNY7,754.5830; 31, pp. 1through 9; 61> 2 to 3City of Longwood3Well No. 3 – 427Well No. 4 – 400Well No. 5 – 400NNY12,133.8030; 33, pp. 1through 10> 2 to 3City of Casselberry2Well No. N-2 – 377Well No. N-1 – 388NNY12,177.7830; 36, pp. 1,2, 3> 2 to 3City of Winter Springs2Well No. 4 – 423Well No. 5 – 440NNY8,995.7630, 37, pp. ithrough 11> 3 to 4Seminole County(Heathrow WTP)2Well No. 1 – 390Well No. 4 – 325NNY4,073.1630; 31, pp. 1through 8; 61> 3 to 4City of Lake Mary5Well No. 1 – 500Well No. 2 – 500Well No. 4 – 695Well No. 5 – 560Well No. 6 – 552NNY13,496.0030; 32, pp. 1,2; 62, pp. i,1, 2> 3 to 4City of Sanford6Well L – 300NNY19,571.0430; 34, pp. 1,40 GW-TargetTABLE 17: Municipal Drinking Water Wells Within A 4-Mile Radius Of General DynamicsUpper Floridan AquifersDistanceRingMilesWater System NameNumberof WellsWell No. andDepth of Wells(feet bls)Level ICont.(Y/N)Level IICont.(Y/N)PotentialCont.(Y/N)PopulationServed ReferencesWell K – 328Well J – 302Well I – 303Well H – 350Well G – 1622, 3; 63, pp.3, 5, 6> 3 to 4Sanlando Utilities6Well No. 1 – 925Well No. 1A – 500Well No. 2 – 420Well No. 2A – 420Well No. 3 – 830Well No. 4 – 550NNY10,710.0030; 35, pp. 1through 8; 97Notes:> Greater thanbls Below land surfaceCont. ContaminationID Identification numberN NoWTP Water treatment plantY YesSee Section 3.3, Targets of this HRS documentation record forthe method by which the population for the water systems listed in Table 17 were calculated.41 GW -Targets 3.3.1 NEAREST WELL

Well ID: The City of Winter Springs has one well located within 0.25 to 0.5 mile southeast from the source at the General Dynamics Longwood site (Refs. 30; 37, p. 1).

Level of Contamination (I, II, or potential): Potential

If potential contamination, distance from source in miles: 0.25 to 0.5

The nearest well value is also based on karst ground wa ter flow documented in Section 3.0.1 of this HRS

documentation record.

Nearest Well Factor Value: 20.0 (Ref. 1, Section 3.2.1.3)

3.3.2 POPULATION

3.3.2.1 Level of Contamination

3.3.2.2 Level I Concentrations

No Level I wells have been identified.

Level I Concentrations Factor Value: 0.00

3.3.2.3 Level II Concentrations

No Level II wells have been identified.

Level II Concentrations Factor Value: 0.0042 GW -Targets 3.3.2.4 Potential Contamination

Distance-weighted population values for potential contamination ground water targets for the Upper and Lower Floridan aquifer are presented in Table 18. Gr ound water flow in the Floridan aquifer system is mostly through porous limestone, and is enhanced by networks of small fractures or solution openings that occur along joints or bedding planes. In some ar eas, flow may be through large cavernous features of paleokarst, resulting in a dual-porosity flow system (Ref. 68, pp. 19, 21, 23). Karstic ground water flow occurs in the Floridan aquifer within the entire 4- mile radius of the source at the General Dynamics Longwood site (Ref. 78).

TABLE 18: Distance-Weighted Population Values - Karst

Distance Category (Miles) Population Distance-Weighted Population Value (Ref. 1, Table 3-12) References

Greater than 0 to 1/4 0 0 30

Greater than 1/4 to 1/2 4,497.88 3,233 30; 37, pp. i through 11

Greater than 1/2 to 1 4,497.88 2,607 30; 37, pp. i through 11

Greater than 1 to 2 18,428.64 8,163 30; 31, pp. 1 through 8; 33, pp. 1 through 10

Greater than 2 to 3 41,061.92 26,068 30; 31, pp. 1 through 8; 33, pp. 1 through 10; 36, pp. 1, 2; 37, pp. i through 11

Greater than 3 to 4 47,850.20 26,068 30; 31, pp. 1 through 8; 32, pp. 1, 2; 34, pp. 1, 2, 3; 35, pp. 1 through 8

Calculations:

Sum of Distance - Weighted Population Values: 66,139 Sum of Distance - Weighted Population Values ÷ 10: 6,613.9

Potential Contamination Factor Value: 6,613.9

3.3.3 RESOURCES

Wells used for resources were not identified within a 4-mile radius of the General Dynamics property.

Resources Factor Value: 0.00

3.3.4 WELLHEAD PROTECTION AREA

Seminole County, Sanlando Utilities, and the cities of Lake Mary, Sanford, and Casselberry have wellhead protection areas (Refs. 31, p. 2; 32, p. 1; 33, p. 1; 34, p. 1; 35, p. 1; 36, pp. 1, 2). Therefore, wellhead protection areas are located within the 4-mile radius of the source at General Dynamics (Ref. 30).

The closest wells with wellhead protection areas ar e operated by the Seminole County and are located

between 1 and 2 miles of the source at the General Dynamics Longwood site (Refs. 30; 31, pp. 1, 2).

Wellhead Protection Area Factor Value: 5.00