EPA/ROD/R04-95/233
July 1995
EPA Superfund
Record of Decision:
Homestead Air Reserve Base
OU6, Site SS-3, FL
6/22/95
-------
FINAL
RECORD OF DECISION
FOR
OPERABLE UNIT 6, SITE 8S-3,
AIRCRAFT W ASHRACK AREA,
HOMESTEAD AIR RESERVE BASE, FLORIDA
. March 1995
Prepared for:
u.s. Army Corps of ENGINEERS
Missouri River Dvision
Omaha District
Omaha, Nebraska
Prepared by:
Montgomery Watson
3501 North Causeway Boulevard, Suite 300
Metairie, Louisiana 70002
-------
RECORD OF DECISION
Operable Unit 6, Site SS-3,
Aircraft Washrack Area
Homestead Air Reserve Base
Homestead, Florida
FDEP Facility No. 138521996
March 1995
Montgomery Watson appreciates the opportunity to work for the U.S. Army Corps of Engineers,
at the Homestead Air Reserve Base facility in Homestead, Florida. If you have any questions or
comments concerning this report, please contact one of the individuals listed below.
Respectfully submitted,
MONTGOMERY WATSON
J~~L/~~~
Randall S. Luwe, P.G.
P . ect Manager
({L~
Je . Gaccetta, P.G.
Project Engineer
-------
Homestead Air Reserve Base, Florida
Operable Unit 6, Site SS-3
Aircraft Wash rack Area
Declaration for the Record of Decision
-------
DECLARATION STATEMENT
FOR THE
RECORD OF DECISION FOR
OPERABLE UNIT NO.6
HOMESTEAD AIR RESERVE BASE SUPERFUND SITE
SITE NAME AND LOCATION
Homestead Air Reserve Base
Homestead, Dade County, Florida
Operable Unit No.6, Site SS-3,
Aircraft Washrack Area (Former Site SP-7)
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for Aircraft Washrack Area,
Operable Unit No.6 (OU-6), Site SS-3, at Homestead Air Reserve Base (ARB) (formerly
Homestead Air Force Base), in Homestead, Florida. The selected remedial action is chosen
in accordance with CERCLA, as amended by SARA, and, to the extent practicable, the
National Oil and Hazardous Substances Pollution Contingency Plan (NCP). This decision is
based on the administrative record for this site.
The State of Florida, the U.S. Environmental Protection Agency (USEPA), and the U.S. Air
Force (USAF) concur with the selected remedy presented in this.Record of Decision (ROD).
ASSESSMENT OF THE UNIT
Actual or threatened releases of hazardous substances from this site, if not addressed by
implementing the response action selected in this ROD, may present an imminent and
substantial endangerment to public health, welfare, or the environment
-1-
-------
DESCRIPTION OF THE SELECTED REMEDY
Operable Unit No.6 represents the only unit at Homestead ARB to be addressed by this
ROD. This operable' unit addresses the source of contaminated soil and groundwater
(i.e., LNAPL) and the removal of contaminated soil. This action addresses the principal
threat at the site by removing the contaminated soils and the source, LNAPL. The localized
contaminated groundwater is expected to naturally attenuate to within standards protective of
human health and the environment and below acceptable risk soon after the removal of the
contaminated soil and LNAPL.
The major components of the selected remedy include:
.
Excavation of soiVrock from an approximate 125 ft by 75 ft by 6 ft (2,100 cubic
yards) area. The soil is slated for a disposal at a RCRA permitted facility. The
facility will use off-site thermal desorption technology to treat the waste. Fill
material will be brought to the site to return the area to grade.
.
During the excavation a maximum of approximately 5,600 gallons of LNAPL is
expected to be recovered. The LNAPL is slated for energy recovery (Le., recycling)
at a facility to be determined.
.
Groundwater monitoring will be performed at the site for 5 years to show that natural
attenuation will meet performance standards (clean-up levels) applicable to
contaminated groundwater.
.
Five year review to determine whether the site remains protective of human health
and the environment.
.
Institutional controls to avoid contact with contaminated groundwater until protective
levels have been met.
STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the environment, complies with
Federal and State requirements that are legally applicable or relevant and appropriate to the
remedial action, and is cost-effective. This remedy utilizes permanent solutions and
alternative treatment and resource recovery technologies, to the maximum extent practicable,
I
-2-
-------
and satisfies the statutory preference for remedies that employ treatment that reduces
toxicity, mobility, or volume as a principal element.
Because the remedy will result in hazardous substances remaining on-site above health-based
levels (benzene in groundwater), a review will be conducted within five years after
commencement of remedial action to ensure that the remedy continues to provide adequate
protection of human health and the environment. The review will be perfonned every five
years thereafter until protectiveness is achieved.
UNITED STATES AIR FORCE .
HOMESTEAD AIR RESERVE BASE
Date:
By:
-3-
-------
Homestead Air Reserve Base, Florida
Operable Unit No.6, Site SS-3,
Aircraft Washrack Area
(Former Site SP-7)
Decision Summary for the
Record of Decision
-------
TABLE OF CONTENTS
Pa~e
SECfION 1.0 - SITE NAME, LOCATION, AND mSTORICAL DESCRIPTION ........ 1
1.1 Site Description ......... ............... .... ....... ... ....... ... ... ...... ......... .... 2
1.2 Regional Land Use................ . .. . . . . . . . . .. .. .. . . . . . . . . . . . . . .. . . . . . . . . . . . .. . . .. . 2
1.3 Surface Hydrology..... ........., ..... ..... ............ ..... ... ......, ..... ...... .... 3
1.3.1 Regional Hydrogeologic Setting.... ...................... ...... ... ...... ... ....... 3
1.4 Site Geology and Hydrogeology. ... . .... .. ... .. .. ... .. . .. ....... . . . ... .. ... ...... . 5
SECfION 2.0 - SITE mSTORY AND ENFORCEMENT ACTIVITIES.................... 6
Operable Unit No.6 History [[[ 6
2.1.2 Past Site Usage... .... [[[ .... 6
2.2. Enforcement History ......... [[[ 6
2.2.1 CERCLA Regulatory History ....... . ... . .. ... .. .. . . . .. ... . . . . .. . . . . . . ... . . . . ... .. . 6
2.3 Investigation History [[[ 8
2.3.1 IRP Phase I - Record Search ....... .........................,...................... 8
2.3.2 IRP Phase n - Confmnation/Quantification...................................... 8
2.3.3 IRP Phase ill - Technology Base Development........ .......... ............... 9
2.3.4 IRP Phase IV - Additional Investigations......................... . . . . . . .. . . . . .. . 9
2.3.5 1990 and 1991 Remedial Investigation ........................................... 10
2.3.6 1993 Remedial Investigation Addendum............"............................. 10
2.4 Community Relations History.... . ..... ... .. ....... ... .................. . . '.' .. .... 11
2.5 Scope and Role of Response Action... . . . .. . .. . . . . ... .. . .. . . . . .. . . . . . . . . . . . . . . ... 11
2.6 Summary of Site Characteristics................................................ ... 12
2.6.1 Nature and Extent of Contamination.............................................. 12
2.6.2 Soil Investigations .. ....... ..... .... ... ............ ... ......... ......... .......... ... 14
2.6.2.1 Volatile Organic Compounds. . . . . .. .. .. . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . .. . 14
2.6.2.2 Base Neutral/Acid Extractable Compounds... ... ....... ...... ......... 15
2.6.2.3 Organochlorine PesticideslPCBs ........ ......... .... ..... ............. 16
2.6.2.4 Metals and Cyanide.... .. . .. ..... .. ..... ... ... ...... . .... .... ...... ....... 16
2.6.2.5 Summary Section for Soils. ............ .................................. 18
2.6.3 Groundwater Investigations. ...... ... ............ ... .. . .................. .... ...... 19
2.6.3.1 Volatile Organic Compounds ............................................ 20
2.6.3.2 Base Neutrall Acid Extractable Compounds ........................... 21
2.6.3.3 Organochlorine PesticidesIPCBs ..... ... ............................... 22
2.6.3.4 Inorganic Compounds[[[ 23
2.6.3.5 Summary Section for Groundwater .................................... 26
2.6.4 Sediment And Surface Water Investigations........................ ............. 26
2.6.4.1 Volatile Organic Compounds.... '''''''' ....,.... ......... ............. 27
-------
1- ~
TABLE OF CONTENTS
Pa~e
Summary of Site Risk .........,. ...... ...................................,.......... 30
Selection of Chemicals of Potential Concern.. . . . . . . . . . . . . . .. .. . . . . . . . ... . . . .. .. 31
Exposure Assessment.. ...... ... . ..... . .. .... .. . .. '" ....,. ..............,.......... 32
Toxicity Assessment. ... ..,... ......... ... ...... ............... ..... .... ......... .... 33
Risk Characterization. . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . .. . . . ... . ., ... . . . . . .. 34
Development of Remedial Goal Options ......................................... 36
Ecological Risk Assessment. . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . ., .. . . . . . . .. 36
Uncertainties in the Risk Assessment............................................. 37
Description of Alternatives..............................................~... . . ..... 37
Alternative 1 - No Action with Groundwater Monitoring. .. . . . . . . . . . . . . . . . .. .. 38
Alternative 2 - Passive LNAPL Recovery, Institutional
Controls, and Natural Attenuation.............................. . . . . . . . . . . . . . .. . ... 39
2.8.3 Alternative 3 - Passive LNAPL Recovery,
Bioremediationl Air Sparging, and Institutional Controls... . . . .. .. .. . .. . . . . ... 39
2.8.4 Alternative 4 - Excavation and Off-Site Thermal Treatment
Disposal of Contaminated Soils, and Natural Attenuation and
Institutional Controls... ."........... ... .. ........................... ......, ... ....... 40
Summary of Comparative Analysis of Alternatives............................. 41
Overall Protection of Human Health and Environment.............. ... ....... 42
Compliance with Federal/State Standards........................................ 42
Long-term Effectiveness and Permanence..... .. .... ............... ...... ....... 42
Treatment to Reduce Toxicity, Mobility or Volume............................ 43
Short-term Effectiveness...... ........... .,......... "'" ........................... 43
Implementability ................................... .......................,.......... 43
Cost. . . . . . . . . . . . . . ... . . . . . . .. .. . . . . . . . . . . . . . . . . . . . . .. . . ... . .. .. .. . .. . ... . . . . .. .. . .. .. 43
State and Community Acceptance...................... ........................... 43
Selected Remedy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ., ... . . . .. . .. ~ . . . . . . . . . .. .. 44
Statutory Determinations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .. . .. .. . .. . . . .. 44
Documentation of Significant C,hanges . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . .. . . ... . . .... 45
2.7
2.7.1
2.7.2
2.7.3
2.7.4
2.7.5
2.7.6
2.7.7
2.8
2.8.1
2.8.2
2.9
2.9.1
2.9.2
2.9.3
2.9.4
2.9.5
2.9.6
2.9.7
2.9.8
2.10
" 2.11
2.12
11
-------
Figure
No.
1-1
1-2
1-3
2-1
2-2
2-3
LIST OF FIGURES
Title
Follows
Paee
Location of Homestead Air Force Base... . ... .. ... .. ....... ..... ... ...........,.. 1
Base Location Map ...... ............ .............. ...... ............ """""" .,.. 2
Site SS-3, Aircraft Washrack Site Map........................................... 2
Sampling Locations - 1987 Investigation.... . ............................. ....... 9
Sampling Locations - 1990 and 1991 Investigation................"............. 10
Sampling Locations - 1993 Investigation.....:.... ... ........... ....... ... ....,.. 11
ill
-------
\- -
I
Table
No.
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
2-10
2-11
2-12
2-13"
2-14
2-15
2-16
2-17
2-18
2-19
2-20
2-21
2-22
2-23
LIST OF TABLES
Title.
. Follows
Paee
Summary of Soil Analytical Results - 1991 Investigation,
Geraghty & Miller.... . . . . .. .. . . .. . . . . . . . . . . . . .. . . . . . . . .. . . . . . . . .. . . . . . . . . . . . . . . . . . . . 14
Summary of Constituents Detected in Soil Samples - 1993 Investigation,
Montgomery Watson.. ...... .. . . . .. ... .. . . . . . . . . . . .. . . . . . . . . . . . .. .. . . . . . . . . . . . . . . . . . 15
Summary of Constituents Detected in Groundwater Samples Collected
in 1990, Geraghty & Miller.. . . . .. . . . . ... . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . 19
Summary of Constituents Detected in Groundwater Samples Collected
in 1991, Geraghty & Miller... .. . .. . . . . . .. . .. .. .. .. . . .. . .. . . . . . . . . . . .. . .. . . . . . . . . . . . 19
Groundwater Quality Criteria........ ... . .. ... .. . ...,.. .. . .. . . .. . . . . . . ... . . . . . . . . .. 20
Snmmary of Constituents Detected in Groundwater Samples - 1993
Investigation, Montgomery Watson. ... .. ..,. ... ... .. . ... ..,.... . . . .. ... .. . . . . . ... 21
Surface Water Quality Control....... '".. .... ........... ... .. .... ...... ..... . ... .... 26
Summary of Sediment Analytical Results - 1991 Investigation,
Geraghty & Miller[[[ .. . . 26
Summary of Surface Water Analytical Results - 1991 Investigation,
Geraghty & Miller......... .:...................... ..........., ...............,...... 27
Summary of Constituents Detected in Sediment Samples -
1993 Investigation, Montgomery Watson.. . . . . . . . . . . . . . . . .. .. ... ., . . . . . . . .. . . . .. 27
Summary of Constituents Detected in Surface Water Samples, 1993
Investigation, Montgomery Watson. . . . . . . . . . . . . . . . .. . . .. . ., .... . . ., . . .. . . . . .. . ... 27
Chemicals of Potential Concern- Site SS-3 ....................................." 32
Exposure Point Concentrations for Groundwater............... .,. ... ... ....... 33
Exposure Point Concentrations for Soil. . . . . . . . . . . . . . . . . . . . .. . . .. . .. . . . . . . ... . ... 33
Equation and Sample Calculations for Hypothetical Future Potable
Groundwater Exposure at Site SS-3............. ...........................,...... 33
Equations and Sample Calculations for Soil Exposure at
Site SS-3 '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 33
Reference Doses for Chemicals of Potential Concern. . . . . . . . . . . . . . . . . . . . .. . . .. 34
Cancer Slope Factors, Tumor Sites, and USEP A Cancer Classifications
for Chemicals of Potential Concern. . . . . . . . . . . . . . . . .. . . . . .. . . .. ... .,. .. .. .. ... .. .. 34
Risk-Based Remedial Goal Options Hypothetical Future Adult
Resident - Groundwater... .. .. . . . .. . .. . . . . . . . . . . . . . .. . . . . . . . . . .... . . . . . .. . ... . . . . . .. 34
Risk-Based Remedial Goal Options and FDEP Soil Target Levels
Hypothetical Future Adult Resident - Soil .,... ..........., ......... """ ....... 36
Risk-Based Remedial Goal Options and FDEP Soil Target Levels
Hypothetical Future Child Resident - Soil...... ............ ...... .,. ...... ... .... 36
Summary of Screening of Remedial Alternatives for Site SS-3 .. . .....,...... 41
-------
DECISION SUMMARY
FOR THE
RECORD OF DECISION
1.0
SITE NAME, LOCATION, AND IllSTORICAL DESCRIPTION
Homestead Air Reserve Base (ARB) is located approximately 25 miles southwest of Miami
and 7 miles east of Homestead in Dade County, Florida (Figure 1-1). The main Installation
covers approximately 2,916 acres while the surrounding areas are semi-rural. The majority
of the Base is surrounded by agricultural land. The land surface at Homestead ARB is
relatively flat, with elevations ranging from approximately 5 to 10 feet above mean sea level
(msl). The Base is surrounded by a canal that discharges to Military Canal and ultimately
into Biscayne Bay approximately 2 miles east.
The Biscayne Aquifer underlies the Base and is the sole source aquifer for potable water in .
Dade County. Within 3 miles of Homestead ARB an estimated 1,600 people obtain drinking
water from the Biscayne Aquifer while 18,000 acres of farmland are irrigated from aquifer
wells (USEP A, 1990). All recharge to the aquifer is through rainfall;
Homestead Anny Air Field, a predecessor of Homestead Air Reserve Base, was activated in
September 1942, when the Caribbean Wing Headquarters took over the air field previously.
used by Pan American Air Ferries, Inc. The airline had developed the site a few years earlier
and used it primarily for pilot training. Prior to that time, the site was undeveloped. Initially
operated as a staging facility, the field mission was changed in 1943 to training transport
pilots and crews.
In September 1945, a severe hurricane caused extensive damage to the air field. The Base
property was then turned over to Dade County and was managed by the Dade County Port
Authority for the next eight years. During this period, the runways were used by crop dusters
and the buildings housed a few small industrial and commercial operations.
In 1953, the federal government again acquired the airfield, together with some surrounding
property, and rebuilt the Site as a Strategic Air Command (SAC) Base. The Base operated
under SAC until July 1968 when it was changed to the Tactical Air Command (T AC) and the
-1-
-------
.N
J
\
\
\
.~ \
,.I 0 " \
. / \ \
\~. ,0 ~ \ \
'~7 : r~.\ r----------\
~,~! '\ : 0 .(/ \)
~ I: ~
..,~~ ./ I I~ I
"\~ ~ ~ I HENDRY COUNTY I )
\ '~~(".JJ FT. MYERS: : PALM BEACH COUNTY
~" 0. c:::- r-----, I .
~ ~~J\ I I I I
'.':i l 1-- I I
I I I I BOCA RA TONel
'r-~ L_-----r~:~~~:~~:~---(
) I FORTe:
~ COLLIER COUNTY: LAUDERDALE
~ ~-- ~---L______f--~I
~"\-.... - - - -: DADE COUNTY QIAMI
~n.\ '- I r--, '=
~ MONROE COUNTY I / ~
.~ I I I PERRINE.! BISCAYNE
- - r let BAY
. : HO~ESTEAD* HOMESTEAD
EVERGLADES - ~ e ~ ARB
NATIONAL: > ,/
~r .;;g
~6~~~
t ~ ~ .
. . ..
~ .
~
~
I \
\~
'0':'
." .
.
. "
~
~. ~~ ,.."-
~D';:I~
. ~~
,&,J:!
~
O'
I
10Mi
I
APPROX. SCALE
20Mi
I
HOMESTEAD AIR RESERVE BASE
HOMESTEAD, FLORIDA
LOCA nON OF
HOMESTEAD AIR RESERVE BASE
AGURE 1-1
-------
4531 st Tactical Fighterwing became the new host. The Base was transferred to Headquarters
Air Combat Command on June 1, 1992.
In August 1992, Hurricane Andrew struck south Horida causing extensive damage to the
Base. The Base was placed on the 1993 Base Realignment and Closure (BRAC) list and
slated for realignment with a reduced mission. Air Combat Command departed the Base on
March 31, 1994 with Air Force Reservists activated at the Base on April 1, 1994. The 482nd
Reserve Fighter Wing now occupies approximately 1/3 of the Base with the remaining 2/3
slated for use and oversite by Dade County.
1.1
SITE DESCRIPTION
OU-6 is the Aircraft Washrack Area, Site SS-3 (former Site SP-7). OU-6/Site SS-3 is
located in the central portion of Homestead ARB, approximately 720 feet north of Building
720 (Figure 1-2). The site covers an area approximately three acres in size and has
dimensions of approximately 320 feet by 400 feet. The site is bordered on the northwest by a
drainage ditch located parallel to Bikini Boulevard, on the southwest by a low grassy swale,
on the northeast by a ditch, and on the southeast by the asphalt Flight Apron 4047 (Figure 1-
3). Stormwater runoff from the Aircraft Washrack and surrounding area is collected in the
drainage ditch and swale located southwest and northeast of the site. The ditch and swale
flow to the northwest towards the drainage ditch. The drainage ditch, adjacent and parallel to
Bikini Boulevard, flows from southwest to northeast for approximately one mile before
draining into the Boundary canal which borders Homestead ARB. One to two feet of water
are typically present in the drainage ditch.
Prior to Hurricane Andrew, the site consisted of a covered, concrete and asphalt aircraft
washrack structure, a utility building and Building 723. Due to damages experienced during
the hurricane, the cover and frame of the washrack are no longer present. The area
surrounding the washrack is covered with grass. The site is underlain by heavily weathered
limestone bedrock of the Miami Oolite formation, which is typically covered with less than
two inches of soil. Approximately 35% of OU-6/Site SS-3 is covered with asphalt and/or
concrete.
1.2
REGIONAL LAND USE
The area adjacent to Homestead ARB including OU-6/Site SS-3, to the west, east, and south
within a half-mile radius is primarily composed of farmland and plant nurseries. Residential
-2-
-------
,-
j.
HOMESTEAD
AIR FORCE BASE
XJ
,"'
........"
-
LE\oŁE
7
HIGHWAY
. ----------
HOMESTEAD
.
.
l Source: USGS 7.5 minute
.i Topographic Quadrangles
CD Arsenlcker, Homestead
~ GouIds, and Perrine. .
:I:
"'0
l~
N
~
LE\oŁE
1000
o
2000
HOMESTEAD AIR FORCE BASE
HOMESTEAD, FlORIDA
BASE LOCATION MAP
FIGURE 1-2
- -
- -
FEET
-------
I
I
I
i
,
i
./
BIKINI BLVD.
SITESS-3
STUDY ARE~
----------------------
----------------------
---------------
--------------------------------------
------
---------------
D
~
~
~
'0
"
~
o
"
~
~
;;;
'"
~
.<
~
"
'.
~
;;
-
/
~
/
--------------------------------------
,--'"
I I
I I
I I
I J
I I
I I
I I
I I
I I
I I
I I
I I
I J
I I
I I
J W I
I ;;i I
I == I
I en I
I> I
I en' I
J en I
I ~ I
I CJ I
I I
I I
I I
~
I rr--. /
: : u I
I I I I
I I , i
I ,,.--
I I I
I:~:II
I I ) I
U:/~
l
I
I
I
('
BLDG.
~ 720!
~ r
100'
I
o
\
APPROXIMATE SCALE
100'
I
AIRCRAFT W ASHRACK
WlJ
- - 7 /--
/ /
/ /
/ /
/
/
/ /
/ /
/ /
/ /
/ /
/ /
/ /
r~/
o
D UTILITY BLDG
LEGEND
FORMER ABOVE GROUND
STORAGE TANK LOCATION
DITCH
HOMESTEAD AIR RESERVE BASE
FLORIDA
SITE 55-3. AIRCRAFT WASHRACK
SITE MAP
FIGURE 1-3
-------
areas are located within a half-mile to the north and southwest of the Base. Woodlands are
located approximately one-half-mile east of the facility and mangroves and marsh occur
adjacent to Biscayne Bay. The Biscayne National Park is located 2 miles east of Homestead
ARB; the Everglades National park is located 8 miles west-southwest of the Base; and the
Atlantic Ocean is approximately 8 miles east of the Base.
1.3
SURFACE HYDROLOGY
Surface hydrology at Homestead ARB, including OU-6/Site SS-3 is controlled by five main
factors: 1) relatively impermeable areas covered by runways, buildings and roads;
2) generally high infiltration rates through the relatively thin layer of soil cover; 3) flat
topography; 4) generally high infiltration rates through the outcrop locations of the Miami
Oolite Formation; and 5) relatively high precipitation rate compared to evapotranspiration
rate. Infiltration is considered to be rapid through surfaces of oolite outcrop and areas with a
thin soil layer. Infiltration rates are accelerated by fractures within the oolite, as well as
naturally occurring solution channels. Precipitation percolates through the relatively thin
vadose zone to locally recharge the unconfmed aquifer.
Natural drainage is limited because the water table occurs at or near land surface. The
construction of numerous drainage canals on Homestead ARB has improved surface water
drainage and lowered the water table in some areas. Rainfall runoff from within Homestead
ARB boundaries is drained via diversion canals to the Boundary Canal.
A drainage divide occurs within the Homestead ARB facility property, running from the
northern end of the facility, toward the center. Water in the Boundary Canal flows generally
south and east along the western boundary of the property, and south along the eastern
boundary, converging at a storm-water reservoir located at the southeastern corner of the
Base. Flow out of the stormwater reservoir flows into Military Canal, which, in turn, flows
east into Biscayne Bay, approximately 2 miles east of the Base. Water movement is typically
not visible in the canals in dry weather due to the lowered water table and the very low
surface gradient (0.3 feet per mile) that exists at the Base.
1.3.1
Regional Hydrogeologic Setting
The regional hydrogeology in the southeast Florida area consists of two distinct aquifers: the
surficial aquifer system, which consists of the Biscayne Aquifer and the Grey Limestone
Aquifer, and the lower aquifer, the Floridan Aquifer.
-3-
-------
Biscayne Aquifer. The Biscayne Aquifer at Homestead ARB consists of the Miami Oolite,
Fort Thompson Formation, and the 'uppermost part of the Tamiami Formation. In general,
the most permeable parts of the aquifer lie within the Miami Oolite and the Fort Thompson
Formation.
The Biscayne Aquifer underlies all of Dade, Broward, and southeastern Palm Beach
Counties. The Biscayne Aquifer is the sole source of potable water in Dade County and is a
federally-designated sole-source aquifer pursuant to Section 1425 of the Safe Drinking Water
Act (SDW A). The Biscayne Aquifer supplies drinking water to approximately 2.5 million
people within local communities. All recharge to the aquifer is derived from local rainfall,
part of which is lost to evaporation, transpiration, and runoff.
The Biscayne Aquifer has reported transmissivities ranging from approximately 4 to
8 million gallons per day per foot (mgdlft) (Allman et al., 1979).
Water-table contours indicate that under natural conditions, groundwater flows southeasterly
toward Biscayne Bay. The hydraulic gradient is approximately 0.3 ftImile. The water table
at Homestead ARB generally is encountered within 5 to 6 feet of land surface, but may occur
at or near land surface during the wet season (May to October). Fluctuations of groundwater
levels and local variations in the direction of groundwater flow are due to several factors:
(1) differences in infiltration potential, (2) runoff from paved areas, (3) water-level
draw down near pumping wells, (4) significant but localized differences in lithology
(e.g., silt-fIlled cavities) and (5) drainage effects of canals and water-level control structures.
Floridan Aquifer. Underlying the low-permeability sediments of the Tamiami Formation
and Hawthorn Group are the formations which constitute the Floridan Aquifer.
The Floridan Aquifer is made up of limestones and dolomites. It is under artesian pressure
and water levels in deep wells may rise 30 to 40 ft above ground surface. Groundwater
within these Miocene and Eocene age formations tends to contain dissolved constituents at
levels significantly above those recommended for drinking water. In view of the poor water
quality and the depth of water yielding zones (800 to 900 feet bgs), the Floridan Aquifer is of
limited. usefulness as a source of potable water supply in the study area.
-4-
-------
1.4
SITE GEOLOGY AND HYDROGEOWGY
The stratigraphy of the shallow aquifer system as determined from soil borings performed
during site investigations by Geraghty & Miller (G&M) and Montgomery Watson consists of
a surficial weathered Miami Oolite ranging in depth from 2 to 6 feet below ground surface
(bgs). The weathered limestone consists of a white to brown semi-consolidated oolitic
limestone. This strata is underlain by consolidated to semi-consolidated oolitic and coral
limestone interbedded with coarse to fine sand and clayey sand layers and lenses down to the
total depth of borings (approximately 40 feet bgs).
The Biscayne Aquifer is one of the most transmissive aquifers in the world. It underlies
Homestead ARB. A thin vadose zone, nominally less than 5 feet deep, overlays the
groundwater table at the site. As previously stated, the aquifer structure is a calcium
carbonate matrix. This lithology is known to have natural concentrations of target analyte
list (TAL) metals. In descending order by concentration, calcium, aluminum, iron
magnesium, sodium, and potassium can be considered the primary metals of carbonate rock.
The other TAL metals occur in trace concentrations, less than 50 milligrams per kilogram
(mglkg). The range and the standard deviations are not provided at this time. It should be
expected that, as precipitation infiltrates and recharge takes place, leaching of metal ions
from the weathered vadose zone and shallow unsaturated zone occurs. Regional data
.collected suggest that concentrations of trace metals can be expected to be the greatest in the
shallow portion of the aquifer because of the proximity to the source (Le., the weathering
vadose structure) and the decreasing retention time with decreasing depth of the saturated
zone. These observations support a hydrogeologic model in which the shallow portion of the
aquifer has a greater horizontal transmissivity than the vertical component during recharge
events. However, it is not possible, from the available data at the site, to quantitatively
differentiate horizontal and vertical components of the aquifer's hydrologic conductivity.
The possible presence of vertical solution zones is well documented in literature. The site-
specific effects have not been fully investigated. Nevertheless, the available data does not
lead to the immediate conclusion that this is a necessary task. The conceptual model, that the
shallow groundwater is discharging to ditches, provided sufficient detail to arrive at the
remedial decision for Site SS-3.
-5-
-------
2.0
SITE IDSTORY AND ENFORCEl\1ENT ACTIVITIES
2.1
OPERABLE UNIT NO.6 mSTORY
2.1.2
Past Site Usage
Two above ground storage tanks with capacities of 750 and 1,500 gallons were used to store
contaminated oils, hydraulic fluids, spent solvents, and other liquid wastes from the flightline
shops. The tanks were located in the western portion of the site, as illustrated on Figure 1-3.
During storage and removal operations, conducted from 1970 to 1980, frequent spills and
overflows onto the ground occurred. Dumping of liquid wastes in the area of OU-6/Site 5S-3
were also reported during this time. Once liquid waste disposal operations were halted, the
tanks were subsequently removed for off-site disposal in 1980. Soils in the fonner tank area,
which were reportedly discolored at the time of tank removal, have either been removed from
the site or covered, leaving no visible evidence of waste residue.
2.2.
ENFORCEl\1ENT IDSTORY
2.2.1
CERCLA Regulatory History
The Comprehensive Environmental Response, Compensation and Liability Act of 1980
(CERCLA) established a national program for responding to releases of hazardous
substances into the environment. In anticipation of CERCLA, the Department of Defense
(DOD) developed the Installation Restoration Program (lRP) for response actions for
potential releases of toxic or hazardous substances at DOD facilities. Like the Environmental
Protection Agency's (EPA's) Superfund Program, the IRP follows the procedures of the
National Oil and Hazardous Substances Pollution Contingency Plan (NCP). Homestead
ARB was already engaged in the IRP Program when it was placed on the National Priorities
List (NPL) on August 30, 1990. Cleanup of DOD facilities is paid for by the Defense
Environmental Restoration Account (DERA), which is DOD's version of Superfund.
The Superfund Amendment and Reauthorization Act (SARA), enacted in 1986, requires
federal facilities to follow NCP guidelines. The NCP was amended in 1990 (see 40 CPR 300
et seq.) to implement CERCLA under SARA. In addition, SARA requires greater EPA
involvement and oversight of Federal Facility Cleanups. On March 1, 1991, a Federal
Facility Agreement (FFA) was signed by Homestead ARB (formerly Homestead AFB), the
-6-
-------
EPA, and the Florida Department of Environmental Protection (FDEP). The FFA guides the
remedial design/remedial action (RDlRA) process.
The purpose of the FF A was to establish a procedural framework and schedule for
developing, implementing, and monitoring appropriate response actions at Homestead ARB
in accordance with existing regulations. The FFA requires the submittal of several primary
and secondary documents for each of the operable units at Homestead ARB. This ROD
concludes all of the remedial investigation/feasibility study (RIlFS) requirements for
Site SS-3 and selects a remedy for Operable Unit No.6.
As part of the RIlFS process, Homestead ARB has been actively involved in the Installation
Restoration Program (IRP) since 1983 and .has identified 27 Potential Sources of
Contamination (PSCs). Nine sites are in various stages of reporting under the RIlFS stage of
CERCLA; ten sites are being investigated in the Preliminary Assessment/Site Investigation
(P AlSr) stage of CERCLA with three of these sites warranting no further investigation; one
site has been closed under the Resource Conservation and Recovery Act (RCRA) guidelines;
and seven sites are being investigated under the FDEP petroleum contaminated sites criteria
(Florida Administrative Code 17-770). Additionally, a RCRA Facility Investigation (RFI) is
underway to evaluate numerous solid waste management units (SWMUs) identified during a
RCRA Facility Assessment (RFA). The following PSCs are currently being investigated
according to the CERCLA RIlFS gUidelines:
OU-l
OU-2
OU-3
OU-4
OU-5
OU-6
OU-7
OU-8
OU-9
Fire Protection Training Area 2 (FT -5)
Residual Pesticide Disposal Area (OT-II)
PCB Spill C.E. Storage Compound (SS-13)
Oil Leakage Behind the Motor Pool (SS-8)
Electroplating Waste Disposal Area (WP-I)
Aircraft Washrack Area (SS-3)
Entomology Storage Area (SS-7)
Fire Protection Training Area 3 (FT -4)
Boundary Cana1lMilitary Canal (SD-27)
Operable Unit No.3, PCB Spill C.E. Storage Compound, has been closed out with the No
Further Action ROD in June 1994. All other CERCLA sites at Homestead ARB are
currently in various phases of the RIlFS process.
-7-
-------
2.3
INVESTIGATION IDSTORY
2.3.1
IRP Phase I - Record Search
An IRP Phase I - Records Search was performed by Engineering Science, and is summarized
in their report, dated August 1983 (Engineering Science, 1983). During the Phase I study,
sites with the potential for environmental contamination resulting from past waste disposal
practices were identified. Thirteen sites of potential concern were identified by reviewing
available installation records, interviewing past and present Homestead AFB employees,
inventorying wastes generated and handling practices, conducting field inspections, and
reviewing geologic and hydrogeologic data. In general, Phase I studies are used to determine
if a site requires further investigation. .
The thirteen sites identified were ranked using the Hazard Assessment Rating Methodology
(HARM) developed by JRB Associates of McLean, Virginia, for the USEP A. HARM was
later modified for application to the Air Force IRP. The following factors are considered in
HARM: (1) the possible receptors of the contaminants; (2) the characteristics of the waste;
(3) potential pathways for contaminant migration; and (4) waste management practices.
HARM scores for the sites ranked at Homestead AFB ranged from a high of 72 to a low of 7
out of 100. Eight of the 13 sites were determined to have a moderate to high contamination
potential, one of which was the Aircraft Washrack. These eight sites were recommended for
further investigation. The remaining five sites were determined to have low potential to
exhibit environmental contamination.
The IRP Phase I Report evaluated the Aircraft Washrack OU-6/Site SS-3 and assigned a
moderate to high HARM score of 69 based on the history of a moderate quantity of liquid
wastes used and disposed of at the site, the high potential for contaminant migration in
surface andlor groundwaters at the site, the presence of extremely permeable soils and
bedrock in the area, and the proximity of the site to a drainage ditch.
2.3.2
IRP Phase n - Confirmation/Quantification
An IRP Phase II study was performed by Science Applications International Corporation
(SAlC), and was reported on in March 1986 (SAlC, 1986). The objectives of Phase n are to
confirm the presence or absence of contamination, to quantify the extent and degree of
contamination, and to determine if remedial actions are necessary. The Aircraft Washrack
was included in the Phase II investigation.
-8-
-------
A total of three shallow monitoring wells (1-7, 1-8, and 1-9) were installed at the site during
Phase II investigations. Groundwater samples were collected and analyzed for oil and,
grease, total organic halogens (TOX), and total organic carbon (TOC). At the time of
sampling, a floating non-aqueous phase liquid (NAPL) was present in well 1-9. A sample of
the NAPL was collected and submitted for oil and grease analysis.' Although the extent of
the contamination could not be delineated, the Phase II investigation indicated that
contamination at OU-6/Site SS-3 was primarily attributable to oil and grease and elevated
TOC, and the presence of halogenated organic compounds was insignificant. A complete
discussion of the methods and results of this study are presented in the Phase II -
Confirmation/Quantification Report (SAlC, 1986).
2.3.3
IRP Phase ill - Technology Base Development
The IRP Phase ill is a research phase and involves technology development for an
assessment of environmental impacts. There have been no Phase m tasks conducted at the
Base to date.
2.3.4
IRP Phase IV - Additional Investigations
The IRP Phase IV investigations consist of two areas of work activity. Phase IV -A involves
additional site investigations necessary to meet the Phase II objectives, a review of all
management methods and technologies that could possibly remedy site problems, and
preparation of a baseline risk assessment to address the potential hazards to human health and
the environment associated with the constituents detected at the site. Detailed alternatives
are developed and evaluated, and a prefen-ed alternative is selected. The prefen-ed alternative
is then described in sufficient detail to serve as a baseline document for initiation of
Phase IV - B.
During the Phase IV-A investigation in 1987, G&M installed ten piezometers (WP-1 through
WP-lO) to delineate the lateral extent and movement of contamination at OU-6/Site'SS-3
(Figure 2-1). Organic vapor concentrations were monitored in the piezometers. The highest
reading (>9,999 parts per million [ppm]) was recorded in piezometer WP-5, located in the
immediate vicinity of the former above ground storage tank locations. Organic vapor
concentrations from eight of the remaining nine piezometers ranged from 4.6 to 36.2 ppm.
An apparently anomalous reading of 160.3 ppm was recorded at piezometer WP-8.
Groundwater from piezometer WP-8 was subsequently determined to be uncontaminated and
the organic vapor reading was not considered to be related to any source.
-9-
-------
"
)
BIKINI BLVD.
PARKING AREA
~=====~~========~~~===~
~GM.1
i
I
I
/
/
i) WP-8
-------------------------------------------------------------
;0
-c
<5
"
'"
'"
~
..,
~
..,
~
~
'"
]
~
a:
:>
"
"
*
~
1
-
.,
-----------------~::~-----------------------------------~~"--
WP.20 I I 81-9 +WGM.3 OWP-10 //'
I I 81-7" /
I J " "
I I " /
I ,+WGM-4 ///"
I I / "
::~ +;V;M':2
I . I ,,///
I I -
I J WP.Si) 81-8
WP.10 I I
I W$M.S+
: W~M-6m
I W I
I ~ I
I 3: I
I rn I WP-40
I> I
I rn I
I rn I
I ~ I
I CJ I
I I
1 I OWP-3
I I
i ! III
I 11 I
: Jii': I
II I I
li)J I
WGM-9.:.a-WG~
~
o
. .
BLDG. 723
o WP-9
o UTILITY BLDG
AIRCRAFT W ASHRACK
AREA
--...
-.
~ :
BLDG.
720
~
8
o
i)
('.
+
m
.
100'
I
o
,
APPROXIMA TE SCALE
100'
I
o
FLiGHTLINE APRON 4047
LEGEND
FORMER ABOVE GROUND
STORAGE TANK LOCATION
SHALLOW MONITORING WEll, INSTALLED BY
SAIC,1984
TEMPORARY PIEZOMETER, INSTALLED BY
G&M,1987
TEMPORARY PIEZOMETER CONVERTED TO
MONITORING WELL. INSTALLED BY G&M, 1987
SHALLOW MONITORING WELL (= 1S FEET),
INSTALLED BY G&M, 1987
DEEP MONITORING WELL (= 3S FEET)
INSTALLED BY G&M, 1987
DEEP MONITORING WELL (= 6S FEET)
INSTALLED BY G&M, 1987
DITCH
HOMESTEAD AIR RESERVE BASE
FLORIDA
SAMPLING LOCA TlONS - 1987 INVE5T1GA TION
SiTE 55-3 AIRCRAFT WASHRACK
FIGURE 2-1
-------
1-
Three of the piezometers (WP-5, WP-6, and WP-8) were converted to permanent monitoring
wells. Nine additional monitoring wells were also installed during the Phase IV-A
investigation. Six shallow wells were constructed to depths of approximately 13 feet below
land surface (bls) (WGM-l through WGM-5, and WGM-7), two intermediate wells were
constructed to depths of approximately 40 feet bls (WGM-6 and WGM-8), and one deep well
was constructed to a depth of approximately 70 feet bls (WGM-9). Groundwater samples
from these nine newly installed wells and two of the three existing wells (1-7 and 1-8) were
collected in March 1987 and analyzed for VOCs (including xylenes), total recoverable
petroleum hydrocarbons (TRPH), and total and dissolved lead. Samples from wells 1-8 and
WP-5 were also analyzed for base neutral/acid extractable compounds (BNAEs). Monitoring
well 1-9, which contained free product, was not sampled.
Due to an erroneously high field blank, laboratory blank, sampler rinsate concentrations, and
poor duplicate agreement, the TRPH data collected in 1987 was determined to be invalid and
ten of the shallow wells were resampled in May 1987. The May samples were analyzed for
Cg-CZO hydrocarbons. Additionally, three of the ten wells resampled in May were analyzed
for BNAEs (WP-5, WP-6, and 1-9). A complete discussion of the methods and results of the
Phase IV-A investigation is presented in G&M's 1989 report Remedial Action Plan for Oil
Spills at the Aircraft Washrack (SS-3) Homestead Air Force Base, Florida.
2.3.5
1990 and 1991 Remedial Investigation
In 1990 and 1991, additional investigations were conducted at OU-6/Site SS-3 by G&M.
The investigations included the collection of soil vapor data in 15 soil borings and in two
monitoring well borehole locations and the subsequent collection of soil and groundwater
samples. The 1990 and 1991 sampling locations are illustrated on Figure 2-2. Five soil
samples were collected and submitted for laboratory analysis. Groundwater samples were
collected from 20 existing monitoring wells in 1990 and 1991. In addition, sediment and
surface water samples were collected from one location within the drainage ditch north-west
of the site. Results of the 1990 and 1991 RI are presented in G&M's report Remedial
Investigation Report for Site SS-3, Aircraft Washrack Area (Former Site SP-7),
October 1992.
2.3.6
1993 Remedial Investigation Addendum
In 1993, Montgomery Watson Americas, Inc. performed additional RI activities to evaluate
the current soil and groundwater quality with respect to the USEP A target compound
-10-
-------
--------------------------- ----------------------------7/--
,- - -, SP7-DMW-0001,- 6 SP7.SL-0004 / /
I SP7.SL-00036.,,m8Io9 fdWGM'3 ////
I I SP7-MW-0014 81-7 / /
I I / /
I I ~-sL-OGos6 6SP7-SL-OG06 //
I lJOWGM-4 ///
I I 6 SP7-5L-OG07 6SP7-SL-OG08 6SP7-SL-OG12
I I l1 SP7-SL-OG09 ~GMo2
I I ~ .SP7-MW-0016 "////
I ! SP7-MW-0017/
SP7.SL-OG10 II d .
I I WP-Sp SP7-SL-OG11/j, 1-8
I I d I I ~ BLDG. 723
I WGM-5p llSP7-SL-OG13-
I WGM-61B SP7-MW-0018 SP7-SL-OG14
I. I
I W I
I ~ I
: ~ : .6$P7-5L-OG1S
: ~ : AIRCRAFT W ASHRACK AREA
I en I
I ~ I
I CJ I
I I
r I
I I
" : :0/
I I I
I I
: : I I
I Jr" ;
II~-
I' I
I I
, )
I /
I / i
WGM-91 : ~WGM.7
~ BLDG.
720
1
..J
BIKINI BLVD.
--------------------------
D
---
~
~
9
c\i
'"
~
'-
'"
~
~
if
~
~
..
~
if
~
'"
~
"
;;
j
~
100'
I
o
I
APPROXIMATE SCALE
100'
I
.;:
-
~GM.1
;
!
/
/
:
SP7-SD-0001
SP7-SL-OG01 o(WP-8
P7 -sw-OGo1""'"
SP7.MW-0013
SP7-SL-0002
D UTiUTY BLDG
.SP7-MW-001S"
D
~
LEGEND
FORMER ABOVE GROUND
STORAGE TANK LOCATtON
DITCH
.
6
SHALLOW MONITORING WELL
INSTALLED BY SAIC, 1984
SOIL BORING LOCA TtON, COLLECTED
BY G&M, 1991
SURFACE WATER SAMPUNG LOCATtON
COLLECTED BY G&M. 1991
SEDIMENT SAMPUNG LOCA TlON
COLLECTED BY G&M, 1991
ABANDONED MONITORING WELL
CD
~
Jd
13
EB
DEEP MONITORING WELLS:
INSTALLED BY G&M. 1991
INSTALLED BY G&M, 1981
HOMESTEAD AIR RESERVE BASE
FLORIDA
SAMPLING LOCATIONS- 1990AND1991 INVESTIGATION
SITE 55-3 AIRCRAFT WASHRACK
FIGURE 2-2
-------
list/target analyte list (Tcur AL) and to fill data gaps from the previous field investigations.
as well as to evaluate any impacts'due to Hurricane Andrew. The 1993 investigation
included the drilling of five soil borings. groundwater sampling of seven shallow and one
deep monitoring well. and the collection of three sediment and surface water samples.
. Sampling locations are illustrated on Figure 2-3.
2.4
CO~TYRELATIONSHISTORY
The Remedial InvestigationlBaseline Risk Assessment Report and Proposed Plan (PP) for
Homestead AFB. OU-6/Site SS-3 were released to the public in June and November 1994.
respectively. These documents were made available to the public in both the administrative
record and an infonnation repository maintained at the Miami-Dade Community College
Library. A public comment period was held from November 8. 1994 to December 22. 1994
as part of the community relations plan for OU-6/Site SS-3. Additionally. a public meeting
was held on Tuesday. November 29.1994. at 7:00 pm at South Dade High School. A Public
Notice was published in the Miami Herald and South Dade News Leader on Tuesday.
November 22. 1994. At this meeting. the USAF. in coordination with EPA Region IV.
FDEP. and Dade County Environmental Resource Management (DERM). was prepared to
discuss the Remedial Investigation. the Baseline Risk Assessment. Feasibility Study. and the
Preferred Alternative as described in the PP. A response to the comments received during
this period is included in the Responsiveness Summary. which is part of this ROD. This
decision document presents the selected remedial action for OU-6/Site SS-3 at Homestead
ARB. chosen in accordance with CERCLA. as amended by SARA and. to the extent
practicable. the National Contingency Plan. The decision for this site is. based on the
administrative record.
2.5
SCOPE AND ROLE OF RESPONSE ACTION
As with many Superfund sites. the problems at OU-6/Site SS-3 are complex.. The
contamination at the site is considered to exist as three media:
One:
Two:
an immiscible layer (LNAPL) in soil/rock pore space
contaminated soil/rock
dissolved constituents in groundwater (contaminant plume)
Three:
The response action authorized by this ROD actively addresses the contamination in two of
the three media; the LNAPL and the contaminated soil/rock. It is anticipated that excavation
-11-
-------
/
/
SITE BOUNDARY ~
;
!
j
BIKINI BLVD.
- - - - - - .5P7.SW-0004 -n\- -- -- - -- --------- -------SP7-SD-0003
- - - - - - - - - - - 'Cf -~ - - - - - - - - - - - - - - - - - - - - - - - - 'SP7:SW-0003 I
I en' 1
I en 1
1 ~ I
I CJ '
1 I
1 I
I I
I
I I
I I
I I
I I
I I
I I
I I
I' I
I I
1 )
I /
I /
/
1/
:-;
D
UTILITY BLDG
. AIRCRAFT WASHRACK
AREA
)l(SP7-MW-0015
I
D
DI
I ,
~
LEGEND
~ FORMER ABOVE GROUND
~ STORAGE TANK LOCATION
DITCH
SURFACE WATER SAMPLING LOCATION
COLLECTED BY M.W., 1993
SOIL BORING LOCATION COLLECTED
BY M.W., 1993
SEDIMENT SAMPUNG LOCATION
COLLECTED BY M.W~ 1993
SHALLOW MONITORING WELLS:
. INSTALLED BY SAIC, 1984
. INSTALLED BY G&M. 1987
)I( INSTALLED BY G&M, 1991
DEEP MONITORING WELLS:
IE INSTALLED BY G&M, 1987 (= 3S FEET)
o INSTALLED BY G&M, 1991
l
BLDG.
720
-------
and disposal of the contaminated soil and extraction of the LNAPL will allow for rapid
attenuation of the localized contaminant plume.
The site poses the principal threat to human health and the environment because of the
possible. but unlikely, ingestion of contaminated groundwater. The source of the
groundwater contamination is suspected to be the LNAPL and the contaminated soil/rock.
The purpose of this response is to eliminate the sources and allow the groundwater to
naturally attenuate at an anticipated rapid pace. This alternative offers a pennanent solution
for the site.
2.6
SUMMARY OF SITE CHARACTERISTICS
The Aircraft Washrack Area used to have aboveground storage tanks with capacities of 750
and 1.500 gallons that were used to store used oils, hydraulic fluids, spent solvents, and other
liquid wastes from the flightline shops. During storage and removal operations conducted
from 1970 to 1980, spills and overflows onto the ground occurred. Dumping of liquid waste
in the area of OU-6/Site. S5-3 was also reported during this time. The total quantity of
organic fluids released to the soil is unknown. Liquid waste disposal operations were halted
in 1980; and the tanks were removed for off-site disposal.
Soils in the fonner tank area, which were reportedly discolored at the time of tank removal,
have either been removed from the site or covered, leaving no visible evidence of w~te
residue.
2.6.1 Nature and Extent of Contamination
The following subsections summarize the five previous investigations conducted at OU-
6/Site SS-3 and the nature and extent of contamination identified during these investigations.
Subsurface investigations at the site were initiated by SAlC in 1986 (SAlC, 1986). Further
soil and groundwater investigations were conducted by G&M in 1987, 1990, and 1991. The
results of the 1987 investigation are reported in Remedial Action Plan for Oil Spills at the
AircraftWashrack (SS-3), Homestead Air Force Base, Florida (G&M, 1989). Results of
work perfonned in 1990 and 1991 are reported in Remedial Investigation Report for Site
SS-3, Aircraft Washrack Area (Former Site SP-7) (G&M, 1992). Additional data were
collected at the site by Montgomery Watson in 1993. The additional Montgomery Watson
investigation was conducted in accordance with the approved Facility Work Plan and Work
-12-
-------
Plan Addenda (G&M, 1991 a,b,c). A sununary of the scope of previous investigations, the
current investigation, and a discussion of data collected to date at QU-6/Site SS-3 is
presented below. .
The initial investigation conducted by SAlC in 1986 included the installation of three
groundwater monitoring wells (1-7, 1-8, and 1-9) in the locations shown on Figure 2-1. No
soil samples were collected during the well installation; results for groundwater samples are
discussed in Section 2.6.3.
Based on the presence of groundwater contamination identified by the SAlC investigation,
G&M performed an investigation in 1987 that included the installation of ten temporary
piezometers (WP-l through WP-lO) and the collection of soil vapor samples at each
piezometer. The temporary piezometers were located in the vicinity of the suspected source
area (the former above ground storage tank location), as well as both up- and down-gradient
of the suspected source area, as illustrated on Figure 2-1. The piezometers were constructed
such that the screened intervals intercepted the groundwater surface. Thus, organic vapors
measured in the piezometers reflected off-gassing of volatile organic contaminants in
groundwater as well as soil vapor. The highest organic vapor concentrations were identified
in piezometers WP-8 (160.3 ppm) and WP-5 (>9,999 ppm). Based on the results of the
vapor survey, piezometers WP-5, WP-6, and WP-8 were converted from temporary
piezometers to permanent monitoring wells. Nine additional monitoring wells (WGM-l
through WGM-9) were also installed during this sampling event. Six of the monitoring wells
(WGM-l through WGM-5 and WGM-7) were completed to depths of approximately 15 feet
'bls, two wells (WGM-6 and WGM-8) were completed to depths of approximately 35 feet bls, ,
and one well (WGM-9) was completed to a depth of 65 feet bls. No soil samples were
collected for laboratory analysis during installation of the nine additional monitoring wells.
Results of 1987 groundwater sampling are discussed in Section 2.6.3.
Based on the results of groundwater sampling, additional investigations were conducted by
G&M in 1990 and 1991. The G&M investigations included the collection of soil organic
vapor monitoring in 15 boring locations and two monitoring well borehole locations, and the
subsequent collection of soil and groundwater samples. The 1990 and 1991 sampling
locations are illustrated on Figure 2-2. Soil samples were collected from depths of 4 to 6 feet
bls at locations SP7-SL-0002, SP7-SL-0005, SP7-SL-0007, SP7-SL-0008, and SP7-SL-0011.
Location SP7 -SL-0002 was identified as a background location for the site. Groundwater
samples were collected from a total of 20 existing monitoring wells in 1990 and 1991. In
addition, sediment and surface water samples were collected from one location within the
-13-
-------
1-
drainage ditch northwest of the site. Results for soil, groundwater, and sediment and surface
water samples are discussed in Sections 2.6.2, 2.6.3, and 2.6.4, respectively.
In 1993, Montgomery Watson performed additional investigation of soil, sediment, surface
water and groundwater at OU-6/Site SS-3 to fill data gaps and evaluate impacts of Hurricane
Andrew. The Montgomery investigation included the drilling of five soil borings, sampling
of seven shallow and one deep monitoring well, and collection of three additional sediment
and surface water samples. Results for soil, groundwater, and sediment and surface water
samples collected during the Montgomery Watson investigation are discussed in Sections
2.6.2,2.6.3, and 2.6.4, respectively. Sampling locations are illustrated on Figure 2-3.
2.6.2
Soil Investigations
This section summarizes data for soils analysis as compiled by G&M in the 1991
investigation (G&M, 1992). Results of soil analyses for the current investigation are
discussed for each analytical group (i.e., VOCs, metals, etc.).
2.6.2.1 Volatile Organic Compounds. 1991 Investigation. Laboratory analytical results
for the 1991 soils investigation are summarized in Table 2-1; complete analytical results are
presented in G&M (1992). The VOCs acetone, ethylbenzene, methylene chloride, styrene,
. and xylenes were detected in the 1991 soil samples collected from the 4 to 6 feet bls depth
interval. Acetone was detected in only the background sample (SP7-SL-0002) at a
concentration of 26 micrograms per kilogram (Jiglkg). This result was qualified because the
reported concentration was less than ~e practical quantitation limit (PQL). Acetone was not
detected in the site samples; however, the detection limit for all site samples was above the
average background concentration of 713 ug/kg for acetone. The fuel constituent,
ethylbenzene, was detected in samples SP7 -SL-0007, SP7 -SL-0008, and SP1SL-OO 11 at
concentrations of 14,000,42,000, and 2,400 Jlglkg, respectively. All samples were qualified
as indicated on Table 4-2. Xylenes, also a fuel constituent, were detected in samples SP7,.
SL-0005 and its duplicate SP7-SL-9005, SP7-SL-0008, and SP1SL-0011. The maximum
concentration of xylene, 71,000 Jlglkg, was detected in sample SP7-SL-0005. The borings
that contained fuel constituents are located in the vicinity of the former above ground storage
tank location where waste fuels and oil were stored (Figure 2-2).
1993 Investigation. One sample, collected from a depth of 1 foot bls in boring
SP7-SL-0017, was analyzed for VOCs in the current investigation. Two VOCs, acetone and
methyl ethyl ketone (MEK), were detected. Acetone was reported at concentrations of
-14-
-------
TABLE 1-1
SUMMARY OF SOIL ANALYTICAL RESULTS
SITE SS-3 AI RCRAFf WASHRACK
GERAGHTY & MILLER, 1991
G&M Sample 1.0. Average Average SP7-SL-0001 SM-SL-0005 SM-SL-9005 SM-SL-0007 SM-Sr..0008 SI'7-SI..-OOll
Sampling Date Carbonate Homestead ARB 9/12191 9/13191 9/13191 9/13/91 9/13/91 9/13/91
ComposItion Background (Background
(tlem.1989) 4-6 n bls Sample)
VOLATILE ORGANIC COMPOUNDS (uglkw dw):
. Acetone 713 [261 J < 17000 <18000 < 17000 <17000 < 16000
Ethylbenzene ND <6.7 <7000 <3400 14000 J 42000J (2400)
Methylene chloride 47.7 [5.31 [210011 36001 <3400 <3400 (3000)
Styrene ND <6.7 <3400 <3400 13000 1 <3400 <3300
Xylenes ND <6.7 71000J 50000 J <3400 21000 J (11000)
BASEINEUTRAL AND ACID EXTRACTABLE
ORGANIC COMPOUNDS (u\:IkW dw):
bis(2-Ethylhexyl) phthalate 480 (30) [5001 U [9201U <4400 <9000 (790)U
2-Methylnaphthalene ND <440 26000 63000 8900 27000 250(X)U
Naphthalene ND <440 15000 36000 4800 17000 11000
METALS (mglk~
Aluminum 8970 425 240 670 610 1900 160 1600
Barium 30 5 4.3 5.2 5.6 6.9 4.9 4.0
Calcium 272000 400000 4 I 0000 350000 360000 400000 360000 400000
Chromium 7.1 3.9 3.1 5.2 5.1 <60 <32 <64
Iron 8190 260 <160 UJ 2001 1801 690J < 170 UJ 910J
Lead 16 1.4 1.4 3.2 <1.4 <0.64 2.5 4.1
Magnesium 45300 875 840 750 710 690 500 980
Manganese 842 5.4 2.3J 7.71 7.5J 201 1.5J 10J
Mercury 0.046 ND <0.013 <0.013 0.016 <0.013 <0.013 0.016
Sodium . 393 910 850 1000 1100 960 1000 600
Vanadium 13 2.3 1.7 2.0 2.0 <60 <32 <64
Zinc 16 ND <63 3.1 <2.7 <120 <65 <130
TOTAL RECOVERABLE
PETROLEUM HYDROCARBONS (mglkg dw) ND <13 5500 4800 860 5900 2400
IIUU6I1UW.C'J.1
Source - Geraghty & Miller, Inc., 1992
mglkg dw - milligrams per kilogram dry weight
uglkg dw - micrograms per kilogram dry welghl
< Analyte was nol detected at or above the Indicated concentration.
[J Value Is greater than Instrument detection Umlt but less than practical quantltatlon Umlt.
J Positive result has been classified as quaUtative.
UJ Analyte was not detected. Classified as quaUtative.
U Result has been classified as undetected.
-------
5,200 and 9,800 J.1g/kg, in the soil sample and its duplicate, respectively. The acetone
detected during the current investigation has been identified as an artifact of the degradation
of pesticide-grade isopropanol used during field decontamination procedures.
Isopropanol samples were analyzed and found to contain acetone at concentrations up to
120,000 J.1g/L. Results of the isopropanol analyses are discussed in the Quality Control
Summary Report (QCSR). MEK, detected at a concentration of 900 J.1g/kg, is a common
laboratory contaminant and was not present in the soil sample in excess of 5 times the
detection limit. It is thus considered to be potentially related to laboratory contamination.
MEK was not detected in the duplicate sample. Details of the data validation process and
subsequent data qualification are presented in the QCSR for the RI. which will be submitted
under separate cover. A summary of VOCs detected in soillbedrock samples during the 1993
investigation is provided in Table 2-2.
2.6.2.2 Base NeutraVAcid Extractable Compounds. 1991 Investigation. Three
BNAs. bis(2-ethylhexyl)phthalate, 2-methyl-naphthalene, and naphthalene, were identified in
the 1991 soil samples. Bis(2-ethylhexyl) phthalate was detected in the background sample at
a concentration of 30 J.1glkg; the result was qualified because it is below the PQL.
Concentrations of bis(2-ethy1hexyl)phthalate detected in site soil samples were qualified as
undetected based on associated quality control data. The polynuclear aromatic hydrocarbon
(P AH) compounds, 2-methylnaphthalene and naphthalene. were detected in all four site-
samples and the duplicate sample. These P AHs were not identified in the background
sample (SP7-SL-0002). Concentrations of 2-methylnaphthalene ranged from 8,900 J.1g1kg in
sample SP7-SL-0007 to 63,000 J.1glkg in the duplicate of sample SP7-SL-0005. PAH
compounds were not detected in the Site SS-3 background sample (SP7-SL-0002) or in
samples from the five locations used to establish average background concentrations for
Homestead AFB. The summary of BNAs detected during the 1991 investigation are
included in Table 2-1
1993 Investigation. Of the soil samples collected. only the soil sample SP7-SL-OO 17 and its
duplicate were analyzed for BNAs. A total of twenty BNAs (sixteen PAH compounds. two
phthalates. and the petroleum products dibenzofuran and carbazole) were identified (Table 2-
2) in both the soil sample and its duplicate collected from boring SP7-SL-0017. Nineteen of
the compounds detected in soil sample (SP7-SL-0017) were qualified because they were
detected at concentrations less than the contract required quantitation limit (CRQL).
Reported concentrations ranged from 11 J.1g1kg to 430 J.1g1kg in the sam~le and from 14 J.1g1kg
to 840 J.1g1kg in the duplicate. The maximum concentration detected in both samples was for
-15-
-------
Analyte
VOA TCL Compounds (uglq) (1)
Aa:umc
- Mt:dJy!!lhyl K.cumc (2-B UW>Oz]C)
PestlcJcJeIPCB TCL Compounds (uWkg) (1)
EndamIf... Sulfate
p,p'-DDD
p,p'-DDE
p,p'.DDr
BNA TCL Compounds (uWkg) (1)
AntIn.cc:nc
Accmplllhcnc
Bcazo(a)Amhnccnc
Bcazo(a)Pyrcnc
Bcmo(b)FWonnIhene
Bcmo(a.b,i)Pc:rylenc
Bczrzo(k)Fluoraclhcnc
Bis(2-E:hylhe1y1) PbtJW.ate
Cmbazdc
o.r,sa.c
!)i'D-Butyl PIuba1ate
Dibcm(A,H)Anthraccnc
Dibcmafuran
Fbxnmhcnc
Fluorene
Indalo(l.2.3-C.D)Pyrcne
2-MClhylnaphtIWcnc
Napblhalene
.PhczwIIhrenc
Pyrcnc
Melals (mf/kg) (Z)
Aluminum
Antimony
Arsenic
Barium
Cadmium
Calcium
OJrcrnimn.Totai
Copper
Iron
Lead
Magnesium
Manganese
Nickel
Potassium
Sodium
Vanadium
Zinc
TABLEZ-Z
SUMMARY OF CONS1TTUENTS DETECTED IN SOn. SA.I\.tPLES
SITE 55-3, AIRCRAFT W ASRRACK
MONTGOMERY WATSON, 1993
Homestead ARB. F10rida
Homestead ARB
-Backgrolmd
~Z n bls
(G&M 199Z)
AVERAGE
CARBONATE
COMPOSITION
(HEM 1988)
Sample 1D.
Sample lnknaJ
Date CoIIeded
SP7SLOOI6 SP7SLOOI7
~Z ~1
3110193 3110193
SP7SUOI7
~1
3110193
Duplicate
SP7SLOOI9 SP7SLOOZO
~Z 4-6
3110193
NA
NA
;}i;?i~20Igi;i;}}i::;i;i:}9g!Xt::i:;:;::
ttt~J.ittHt}ti:~tft}}
NA
NA
NA
NA
---""""""~!!i'W"""" <3 6 <3 6 <36 <4 0
Illilllll'lilltllllll!:II~III:['III!~L"i'I.!::I~:I::1.i~II:.:'I,I:'::.I[i:!':'.li[:l.~!.::il:il:!:' !':!:I:::!~t!![.I::i:
All samples analyzed by Savannah LaboralOria. Ta1lahassec. Florida.
< not detected at spccificd dctccticmlimi1 (1) Ibta Oualin~ for Orvanl~ Comnnnd"
NS - no standard ' J - Estimated Va1uc, 0.1
3 4.4
1650 8,190
4.05 16
1050 45,300
23 842
4.7 13
120 2,390
5.7 398
5.9 13
20 16
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
::::::::::li~~,::i,i,:;::;;:li11;:li;:;I::i,
-
11 J 18 J
20J 37 J
:::::I:.i::li:::!;!:!::I,:::':::!:~'!::~:::::;,:,:::
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
~1 ::::::::::::i:~i::::i:i::::
6.2B --""'60S'B"'"
0.46 B 0.57 B
326000 304000
6 7.2
1.8B 2.6B
662E 730E
:i::::::::i:tf@'iII:~::::::i:::'::::Ii::i:~::::::
--22.7E----- - 19.9E --
:::::::::::~;it::::::;}::::::::::::~~}:{:
ItPiOiiBttt:}}i!2iJftt
--" --.(11"8"". ". -- --, 4:9B'.".
10.6 13.4
NA
NA
NA
NA '
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
(2\ D:au Ou.alifien: for In~nk ComDOnd~
B - Reading is less than CRQL but greater than IDL
E . reponed va1uc is estimated due: to interfcn:nc:c
-------
the PAH fluoranthene. All other BNAs were detected at concentrations less than the
fluoranthene results.
BNAs, primarily P AH compounds, have been detected in one shallow surface soil sample
and four subsurface soil samples at the site. They were not detected in a background sample
(SP7-SL-0002) collected northwest of the site, across Bikini Blvd. on the northwest side of
the drainage ditch (Figure 2-2).
2.6.2.3 Organochlorine PesticideslPCBs. 1991 Investigation. Soil samples collected
in the G&M 1991 investigation were not analyzed for pesticides/PCBs.
1993 Investigation. Four soil samples and a duplicate were analyzed for organochlorine
(OC) pesticideslPCBs. No PCBs were detected. The DDT metabolites p,p'-DDE, p,p'-DDD,
and p,p'-DDT were detected in four of the samples and the duplicate (Table 2-2).
Concentrations ofp,p'-DDE ranged from 0.41 to 9.6 ~glkg; p,p'-DDD concentrations ranged
from 5.8 to 8 ~glkg; p,p'-DDT concentrations ranged from 1.9 to 11 ~glkg. The highest
levels of these compounds were detected in 0-2-foot depth sample at boring SP7-SL-OOI6.
This sample also contained endosulfan sulfate at a concentration of 3.9 ~glkg.
In general, higher levels of pesticides were detected in shallower samples with detected
concentrations decreasing with depth. The highest levels of pesticides detected were found
in the 0-2 foot sample from boring SP7-SL-OOI6, located northwest of the site and northwest
of the drainage ditch (Figure 2-2). Relatively high levels were also present in the 0-2-foot
sample from boring SP7 -SL-OO 19, located in the central portion of the open area northwest
of the washrack (Figure 2-3). The 0 to I-foot sample from boring SP7-SL-OOI7, located
approximately 85 feet southwest of boring SP7-SL-0019, contained lower levels than either
of the 0-2-foot samples. Low levels were also detected in the 4 to 6-foot sample from boring
SP7-SL-0020. There are no promulgated federal or state action levels for pesticides in soils;
therefore, levels are addressed in a health risk assessment in the Baseline Risk Assessment
(BRA) (Montgomery Watson, 1994).
2.6.2.4 Metals and Cyanide. 1991 Investigation. The metals aluminum, barium,
calcium, chromium, iron, lead, magnesium, manganese, mercury, sodium, vanadium, and
zinc were detected in the 1991 soil samples. The metals detected are summarized in
Table 2-1. Aluminum was identified in all site samples at concentrations ranging from
160 milligrams per kilogram (mglkg) in sample SP7-SL-0008 t6 1,900 mglkg in sample
SP7 -SL-0007. With the exception of the 160 mglkg result, all aluminum concentrations were
-16-
-------
in excess of both the average Homestead AFB concentration of 425 mg/kg (Table 2-1) and
the Site SS-3 background sample (SP7-SL-0002) concentration of 240 mg/kg (Table 2-1).
Barium was detected in all samples at concentrations ranging from 4.0 mglkg in
SP7-SL-OOll to 6.9 mg/kg in SP7-SL-0007. All barium results except that of SP7-SL-OOll
were in excess of the Site SS-3 background result of 4.3 mg/kg; all but two results were in
excess of the average Homestead AFB concentration of 5 mglkg. Calcium levels detected in
site soils were below both the Site SS-3 background level and the average for the base.
Chromium was detected in sample SP7-SL-0005 and its duplicate at concentrations of 5.2
and 5.1 mglkg, respectively. These results are in excess of the site and average base
background levels of 3.1 and 3.9 mglkg, respectively. Chromium detection limits for the
remaining three soil samples collected at the site are in excess of background levels. Iron
was detected in two samples (SP7-SL-0007 and SP7-SL-0011) in excess of both the site and
the average Homestead AFB background levels. However, all iron results were qualified
. based on associated quality control measures. Lead was detected in three samples at
concentrations ranging from 2.5 to 4.1 mglkg. All three lead results exceed both the site
background result and average Homestead AFB background result of 1.4 mglkg. Magnesium
was detected in only one sample (SP7 ~SL-OO 11) in excess of background levels. Manganese
was detected in all but one sample in excess of both the site and the average base background
concentration. However, all manganese results were qualified on the basis of associated
quality control results. Mercury was detected in two samples, the duplicate (SP7 -SL-9005)
and SP7-SL-OOll, at concentrations of 0.016 mglkg. These results exceed background
levels. Sodium levels in all site samples were in excess of background levels. Vanadium and
zinc were detected at concentrations of 2.0 and 3.1 mg/kg, respectively, in sample
SP7-SL-0005. Both results were in excess of background levels (Table 2-1).
While several metals were identified at levels above the one site-specific background sample
and the average of the samples from 4 CERCLA sites and I RCRA site, (Table 2-1), all
metals except sodium were detected at concentrations below their respective average
concentration in a carbonate deposit, as reported by Hem (1989).
No cyanide analyses were performed during the 1991 field investigation.
1993 Investigation. One soil sample collected from a depth of one foot bls (SP7 -SL-OO 17)
and a duplicate sample (SP7-SL-9017) were analyzed for metals. Analytical results are
presented in Table 2-2. Fourteen metals were detected in the soil sample and seventeen were
detected in the duplicate. Cadmium, copper, and vanadium were detected in the SP7-SL-
-17-
-------
. 00 17 sample; these analytes plus antimony and nickel were detected in the duplicate sample.
These five metals were reported at concentrations that are less than the reported detection
limits for the samples used to calculate the average Homestead AFB value. Thus, it is not
possible to determine if the reported concentrations exceed naturally-occurring levels (i.e.,
. the average Homestead AFB value for cadmium may. be greater than the reported
concentrations of 0.46 and 0.57 mglkg but less than the detection limits of 2.8 to 3.0 mglkg
for the average background samples). Reported concentrations of aluminum, arsenic,
barium, calcium, total chromium, iron, manganese, sodium, and zinc are below their
respective average concentration in Homestead AFB soils. Lead, magnesium, and potassium
were detected at concentrations in excess of their average Homestead AFB background level.
Lead was detected at a concentration of 46.9 mglkg; the average background concentration
for lead is 4.05 mglkg. Magnesium was detected at concentrations .of 1,490 and 1,680 mglkg
in the sample and duplicate sample, respectively. The average Homestead AFBbackground
concentration for magnesium in the 0 to 2 foot bls depth interval is 1,050 mglkg. Potassium
was not detected above 120 mglkg in the samples used to calculate the average Homestead
AFB background concentration. Reported potassium concentrations for the sample and
duplicate sample are 707 and 640 mglkg, respectively.
Sample SP7-SL-OOI7 was collected northwest of the former above ground storage tank
location, at the approximate location of the 1991 sampling location SP7 -SL-0005. Thus,
results of the two samples provide an indication of the distribution of metals with depth at
. that location. Results were comparable for most metals detected in both the 0-1 ft bls sample
(SP7-SL-0005) and the 4-6 ft bls sample (SP7-SL-0005) with the exception of lead. Lead
was detected in the 0 to 1 foot interval at a concentration of 46.9 mglkg and in the 4 to 6 foot
interval at a concentration of 3.2 mglkg.
Cyanide was not detected in either the sample or the duplicate.
2.6.2.5 Summary Section for Soils. Contaminants detected in OU-6/Site SS-3 soils
include VOCs, BNAs, pesticides, and metals. The VOCs detected (acetone and MEK) are
both common laboratory contaminants; the acetone is thought to be related to the
decontamination process. BNAs, primarily PAHs, have been detected in shallow soils and at
depths up to 6 ft bls. DDT metabolites were detected in shallow soils. The metal arsenic was
identified above the background in the only soil sample analyzed for metals. A summary of
constituents detected in soil samples in 1993 is presented in Table 2-2.
-18-
-------
2.6.3
Groundwater Investigations
The Aircraft Washrack was identified initially during the Phase I IRP. The groundwater
quality at OU-6/Site SS-3 has been monitored during each subsequent phase of investigations
conducted at Homestead AFB. Initial groundwater samples collected from monitoring wells
1-7,1-8, and 1-9, by SAlC during Phase n investigations (1984) were analyzed for oil and
grease (O&G), total organic halogens (TOX), and total organic carbon (TOC).
Concentrations of O&G ranged from 0.15 to 732,000 mgll, with the maximum detection
found in the NAPL at monitoring well 1-9. Concentrations ofTOX and TOC ranged from 10
to 30 Jig/L and 62,000 to 170,000 Jig/L, respectively.
Groundwater samples analyzed for VOCs from fifteen monitoring wells during the Phase N
investigations (1987) indicate the presence of benzene, xylene, 1,I-dichloroethane,
ethylbenzene and toluene in groundwater at monitoring well 1-8. Total BTEX concentration
detected in groundwater at 1-8 was 108.8 Jig/L with a benzene concentration of 45 J.1g/L.
Xylene was detected in groundwater in monitoring well WGM-3 at a concentration of
1.8 J.1g/L. Monitoring well 1-9 was not sampled due to the presence of NAPL.
Based on the analytical results of these previous investigations, additional groundwater
investigations were conducted by G&M in 1990 and 1991. The 1990 groundwater
investigation consisted of sampling seven permanent monitoring wells (1-7, 1-8, WGM-2,
WGM-3, WGM-4, WGM-5, and WP-5). A summary of analytical results from the 1990
groundwater investigation is presented in Table 2-3. The groundwater investigations
performed by G&M in 1991, consisted of collecting samples from thirteen permanent
monitoring wells (1-9, WP-5, WP-6, WP-8, WGM-3, WGM-6, SP7-MW-0013 through
SP7-MW-0018, and SP7-DMW-0001). NAPL was encountered during sampling in
monitoring wells 1-9 and SP7-MW-OOI6. A summary of the 1991 groundwater analytical
results is presented in Table 2-4.
The 1993 remedial investigation conducted by Montgomery Watson was performed to fIll
data gaps from the 1991 RI conducted by G&M and evaluate the groundwater quality with
respect to the USEPA target compound list (TCL) and target analyte list (TAL) to develop a
comprehensive evaluation of the site. Additionally, the 1993 investigation purpose included
evaluating changes in site character due to Hurricane Andrew. A summary of results is
presented in the following sections. Groundwater results are compared to Florida
Groundwater Guidance Concentrations, Florida 17-770 target cleanup levels, Federal EP A
-19-
-------
TABLE 2~3
SUMMARY OF CONSTITUENTS DETECTED IN GROUNDWATER SAMPLES
COLLECTED IN 1990 AT SITE SS~3, AIRCRAFT W ASH RACK
Homestead Air Reserve Base, Florida
Analyte
G&M Sample J.D. 1-7 1-8
Savannah I.D. 13572-1 13572-2
Sampling Date Iln/90 IIn/90
1-8
13572-8
11n/90
DUPLlCA TE
WGM-2 WGM-3 WGM-4 WGM-5
13572-3 13572-4 13572-5 13572-6
11n/90 1 In/90 IIn/90 11/7/90
WP-5
13572- 7
lln/90
EQUIPMENT
BLANK
13572-9
1 In/90
VOLATILE ORGANIC COMPOUNDS ("gll,):
Acetone <25 350J 320 <25 <25 <25 <25 <25 <25
Benzene <5.0 24 24 . <5.0 <5.0 <5.0 <5.0 <5.0 <5.0
BASElNmrrRAL AND ACID EXTRACTABLE
ORGANIC COMPOUNDS C"g!I.):
Naphthalene <10 21 <10 <10 <10 <10 <10 33 <10
TOTAL RECOVERABLE
PETROLlWM HYDROCARBONS (mefL) <1.0 4.5 <1.0 <1.0 <1.0 <1.0 <1.0 5.4 <1.0
ugl Micrograms per liter
mg. Milligrams per liter
NS Not Standard
NA Not Analyzed
< Analyte was not detected at or above the Indicated concentration
J Positive result has been classified as qualitative.
11/11/94
...ITF488'11IITAB2.3
-------
TABLE 2-4
SUMMARY OF CONSTITUENTS DETECfED IN GROUNDWATER SAMPLES
COLLECTED IN 1991 AT SITE SS-3. AIRCRAFT WASHRACK
Homestead Air Reserve Base. Florida
(page 1 or 3)
G&M Sample lD. SP7-I-09 SP7-WP-5 SP7-WP-6 SP7-WP-8 SP7- WGM-3 SP7- WGM-6 SP7-MW-0013
Anal)1C SavanDah LD. 37571-2 37541-3 37541-2 37541-1 37471-4 37541-6 37541-5
Sampling Dale 11120191 11119191 11/19m 11119191 11115191 11/19191 11/19191
VOLATILE ORGANIC COMPOUNDS (ug/L):
Ethylbcnzene II 0.0 0.0 0.0 0.0 0.0 0.0
2-Hcxanooe <10 <10 <10 <10 <10 <10 <10
Xylenes 5.1 I 0.0 0.0 0.0 0.0 0.0 0.0
BASEINEUTRAL AND ACID EXTRACTABLE
ORGANIC COMPOUNDS (ug/L)
bis(2-Ethylhexyl) phthala1e <100 [3.8] UI [1.4] UI (0.76J UI <10 [5.8J U [6.0J UI
Butylbcnzylphthala1e <100 <10 <10 <10 <10 <10 <10
Dj-n-oClylphr.hala1C [28] I <10 <10 <10 <10 <10 <10
Dibcnz.ofuran <100 <10 <10 <10 <10 <10 <10
Fluorene <100 [1.6J I <10 <10 <10 <10 <10
2. Meth ylnaphthalellC 120 31 <10 <10 <10 <10 <10
Naphthalene [70] 27 <10 <10 <10 <10 <10
METALS (ug/L): 300c00 I
Alumioum <200 19001 18000 I 4400 I 1400 12000 I
Arsenic <10 UJ
-------
~ ~
TABLE 2-4
SUMMARY OF CONSTITUENTS DETECfED IN GROUNDWATER SAMPLES
COLLEcrED IN 1991 AT SITE SS-3. AIRCRAFT WASHRACK
Homestead Air Reserve Base, Florida
(page 2 or 3)
G&M Sample LD. SP7.MW-0014 SP7.MW.9014 SP7-MW-0015 SP7.MW-0016 SP7-MW-OOl1 SP7-MW-0018
ADalyte SaYaDDah LD. 37~16 374ro-11 37541-4 37571-1 37471-1 37471-5
SampiiDg Dale 11/14191 11/141'91 11/19191 11120191 11/15191 11/15191
VOLATILE ORGANIC COMPOUNDS (ugIL): 11 15 <5.0 51 <5.0 <5.0
EthylbcllZCne
2-Hcxanone <10 <10 <10 89 <10 <10
Xylenes 14J 6.6J <5.0 21J <5.0 <5.0
BASE/NEUfRAL Arm ACID EXTRACI'ABLE
ORGANIC COMPOUNDS (ug/L) [1.9] UJ [0.68) UJ
bis(2-Ethylhcxyl) phthalate [5.5] J (26) U <10 [1.1) UJ
Butylbcuzylphthala1e (03)J 10 <10 <100 <10 <10
Di-n-Odylphthalale [03] J 10 <10 <100 <10 <10
Dibcnzofura.n <10 [0.5) <10 <100 <10 <10
Fluaene [1.1] [1.3] J <10 <100 <10 <10
2-Methylnaphthalene 32 41 <10 220 <10 <10
Naphthalene 37 51 <10 130 <10 <10
METALS (ug/L):
Aluminum 7100J 5600J 7600 J 1500 6300 J 18000
Arsenic <10 VJ <10 VJ 22J <10 UJ <10 VJ
-------
TABLE 2-4
SUMMARY OF CONSTITUENTS DETECTED IN GROUNDWATER SAMPLES
COLLECTED IN 1991 AT SITE SS-3, AIRCRAFT W ASHRACK
Homestead Air Reserve Base, Florida
(Page 3 of 3)
Analyte
G&MSampieLD. SP7.DMW-0001 lRIPBI..ANK SP7-EB-0024 SP7-~
Savanuah LD. 37471-3 11 37471-2 37541.7
Sampling Date 11/15/91 11115/91 11115191 11/19/91
VOLA TILE ORGANIC COMPOUII.'DS (ugIL):
Ethyl beuz.eue <5.0 0.0 <5.0 <5.0
2-Hexaooue <10 <10 <10 <10
Xyleues <5.0 <5.0 <5.0 <5.0
BASFJNEUTRAL AND ACID EXTRACTABLE
ORGANIC COMPOUNDS (ugIL)
bis(2-Ethylhexyl) pIuhalate (0.61 J NA (0.8) (3.8)
Butylbenzylpluhalate <10 NA <10 <10
Di-o-odylpluhalale <10 NA <10 <10
DibenzofuraD <10 NA <10 <10
Auareue <10 NA <10 <10
2-Methylnaphthaleue <10 NA <10 <10
Naphthaleue <10 NA <10 <10
METALS (ugIL):
Aluminum 6800 J NA <200 <200
Arseuic <10UJ NA <10 <10
Bariwn 501 NA <10 <10
Beryllium <5.0 UJ NA <5.0 <5.0
Calcium 1800000 J NA 270 370
Olromium 52J NA <10 <10
Cobalt .20 UJ NA <0.20 <.1>.20
Nickel <40 UJ NA <40 <40
Potassium 2400 J NA 4200 <1000
Selenium <5.0 UJ NA <10 <10
Sodium 41000J NA <500 <500
Thallium <5.0 UJ NA <10 <10
Vaoadium 32J NA <10 <10
Zinc <20 UJ NA <20 21
TOTAL RECOVERABLE
PETROLEUM HYDROCARBONS (mgIL) <1.0 UJ NA <1.0 UI <1.0 UJ
TOTAL DISSOL VEl) SOLIDS (mgIL) NA NA NA NA
BIOCHEMICAL OXYGEN DEMAND (mgIL) NA NA NA NA
TOTAL SUSPENDED SOLIDS (mgIL) NA NA NA NA
ALKALINITY (mgIL) NA NA NA NA
TOTAL ORGANIC CARBON (mgIL) NA NA NA NA
SULFATE (mgIL) NA NA NA NA
SULFIDE (mgIL) NA NA NA NA
HARDNESS as CaC03 (mgIL) NA NA NA NA
Footnotes
11 QC Sample (all Trip Blank Samples showed identical results and are a.s5"ciak.d
with preceeding ground-water samples).
ugIL - miaograms per liter
m~ - milligrams per liter
N - No Standard
NA. Not Anayl=!
< - Analyte was not detected at or above the indicated concentration
[ ] - Value is greater than the io.suuffient detection limit but less than the practical quaotitation limit.
J - Positive result has beeD classified as qualitative
U - Result has beeD classified as undetected.
UJ - AuaI yte was DO( detected. Oassified as qualitative ...\~1\TMtN
11111$4
-------
primary and secondary drinking water standards, Maximum Contaminant Levels (MCLs,)
and MCL goals (MCLG) (Table 2-5).
2.6.3.1 Volatile Organic Compounds. 1990 and 1991 Investigations. Five VOCs,
including benzene, toluene, ethylbenzene, xylenes, and acetone, were detected in
groundwater samples collected during the 1990 and 1991 field investigations at QU-6/Site
SS-3. Benzene was detected in groundwater sample 1-8 and its duplicate, at a concentration
of 24 ~gIL, which was above the Federal MCL of 5 ~gIL and the Florida Primary Drinking
Water Standard and Section 17-770, FAC cleanup target level of 1 ~gIL (Tables 2-4 and 2-
5). . In addition, acetone was detected in sample 1-8 and its duplicate at concentrations of 350
and 320 ~g/L, respectively. Ethylbenzene was detected in samples 1-9, SP7-MW-OOI4,
SP7-MW-9014 (the duplicate of SP7-MW-OOI4), and SP7-MW-OOI6 at concentrations of
11, 11, 15, and 51 ~gIL, respectively, which are well below the Federal MCL of 700 ~gIL.
However, these concentrations are above the Florida Groundwater Guidance Concentration
of 2 ~gIL. Xylenes were detected in samples 1-9, SP7-MW-0014, SP7-MW-9014, and
SP7-MW-0016 at concentrations of 5.1, 14, 6.6, and 21 ~gIL which are below the Federal
MCL of 10,000 ~gIL and the Florida Groundwater Guidance Concentration of 50 ~g/L.
Additionally, 2-hexanone was detected in sample SP7-MW-OOI6 at a concentration of 89
~gIL.
Concentrations of BTEX, detected in all samples except sample SP7-MW-0016, were below
the Section 17-770, FAC target cleanup level of 50 ~g/L. In 1987, the dissolved BTEX
contaminant plume was confmed to the vicinity of monitoring well 1-8. During the 1990 and
1991 investigation, the dissolved BTEX plume had increased in area and is limited to the
vicinity between the former above ground storage tank area and the drainage ditch parallel to
Bikini Boulevard.
1993 Investigation. Groundwater samples were collected from monitoring wells SP7-MW-
0014, SP7-MW-OOI6, and SP7-DMW-OOOI and analyzed for TCL VOCs. Groundwater
analytical results indicate benzene, ethylbenzene, and total xylene in sample SP7-MW-OOI6
and its duplicate at concentrations of 38 and 70 ~g/L, 120 and 160 ~g/L, and 100 and 150
~g/L, respectively. These benzene concentrations are above the Federal MCLs, Florida
Primary Drinking Water Standard and Section 17-770, FAC cleanup target levels. An
estimated quantity of acetone was also detected in duplicate sample SP7-MW-9OO16 at
9 ~gIL. Two anomalous values of chloroform were found at an estimated quantity of 1 ~g/L
in samples SP7-MW-0014 and SP7-DMW-OOOI. Fourteen TICs were identified in sample.
-20-
-------
TABLE 2-5
GROUNDWATER QUALITY CRITERIA
Analyte
Rorida
Drinking
Water
Standards
Rorida
17-1770
EPA
Drinking
Water
Standards
EPA Muimum
Contaminant
Level Goal
VOLATILE ORGANIC COMPOUNDS (ug/L);
Ethylbenzene
2-Hexanone
Xylenes
Benzene
700
NS
10.000 k
I k
b
NS
b
I
BASEINEUTRAL AND ACID EXTRACf ABLE
ORGANIC COMPOUNDS (ug/L):
bis(2-Ethylhexyl) phthalate
Butyll:ienzylphthalate
Di-n-octylphthalate
Dibenzofuran
Ruorene
2-Methyb1aphthalene
Naphthalene
Phenanthrene
6
1400
10
NS
10
NS
10
NS
NS
NS
NS
NS
c
d
d
NS
METALS (ugIL);
Aluminum
Arsenic
Barium
Beryllium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Potassium
Selenium
Sodium
Thallium
Vanadium
Zinc
2001
50 Ie
2000 k
4
NS
lOOk
NS
10001
3001
ISle
NS
501
2k
lOOk
NS
50k
160.000 k
2
NS
5000 I
NS
NS
NS
NS
NS
NS
NS
NS
NS
50
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
TOTAL RECOVERABLE
PETROLEUM HYDROCARBONS (mgIL)
NS
5
700i
NS
10000 i
5
700i
NS
10000 i
4f
NS
NS
NS
NS
NS
NS
NS
Of
NS
NS
NS
NS
NS
NS
NS
50 TO 200 h
50g
2000i
4
NS
looi
NS
1300s
300h
15
NS
50h
2i
loog
NS
SOi
NS
2/1 f
NS
5000 h
NS
NS
2000i
4
NS
looi
NS
1300
NS
o
NS
NS
2i
100
NS
50i
NS
O.Sf
NS
NS
NS
NS
uOl~
ug/1,. - micrograms per liter
niWL - milligrams per liter
NS - No Standard
b - The total of volatile organic aromatics (benzene. toluene.ethylbenzene and xylenes) must be <50 uJtIL to meet F AC 17-770 guideli
c - The total of polynuclear aromatic hydrocarbons excluding naphthalenes must be <10 ugll.. to meet rAC 17-770 guidelines.
d - The total of naphthalenes and methyl naphthalenes must be <100 ugIL to meet FAC 17-770 guidelines.
f-Numbers represent EPA's Proposed Primary MCL or Proposal MCLG. Federa1 Register. Vol. 55. No. 143. July 1990.
g - Numbers represent EPA's Pri~CL for Inorganics.
h - Numbers represent EP A's Seco MCL for Inorganics which are non-enforceable taste. odor or appearance guidelines.
i-Numbers represent EPA's Final M effective July 1992. Federal Register. January 30, 1991 and July I. 1991.
k - Aorida Primary Drinking Water Standard.
1- Rorida Secondary Drinking Water Standard.
m - Numbers represent EPA's MCL's (July 1992)
s - Final Action 1.evel- The fmallead actIon level is exceeded if the level of lead/copper in more than 10 percent
of the targeted tap samples is greater than the action level (90th percent).
-------
groundwater at SP7-MW-0016 or its duplicate. Groundwater analytical results are provided
in Table2-6.
Laboratory QAlQC data indicate 1,2-dichloropropane concentrations in one equipment blank
and two field blanks. Additionally, toluene was detected in one field blank sample. QAlQC
results are discussed in the QCSR submitted under separate cover.
2.6.3.2 Base NeutraVAcid Extractable Compounds. 1990 and 1991 Investigations.
Seven BNAs were detected in the 22 groundwater samples, including two duplicates,
collected at QU-6/Site SS-3 in 1990 and 1991, as shown in Tables 2-3 and 2-4. Three of
these BNAs, fluorene, 2-methylnaphthalene and naphthalene, are PADs. Fluorene was
detected in monitoring wells SP7-MW-OOI4 and SP7-MW-9014 (the duplicate of SP7-MW-
0014) at concentrations of 1.1 and 1.3 Jlg/L, respectively, which are below the Florida
Groundwater Guidance Concentration of 10 J,lglL. 2-methylnaphthalene was detected in
monitoring wells SP7-MW-0014, SP7-MW-9014 (the duplicate of SP7-MW-OOI4) and SP7-
MW-0016 at concentrations of 32,41, and 220 Jlg/L, respectively. Naphthalene was detected
in SP7-MW-0014, SP7-MW-9014 (the duplicate of SP7-MW-0014) and SP7-MW-0016 at
concentrations of 37,51, and 130 J.1g/L, respectively, which exceeds the Florida Groundwater
Guidance Concentration of 10 Jlg/L.
Total naphthalene concentrations were detected in 1-8 and WP-5 (collected in 1990) at a
maximum concentration of 33 JlglL and 1-9, WP-5, SP7-MW-0014, SP7-MW-9014 (the
duplicate of SP7-MW-0014), and SP7-MW-OOI6 (collected in 1991) at concentrations of
190,58,69,92, and 350 Jlg/L, respectively. The total naphthalene concentrations are below
the Section 17-770, F AC cleanup criteria of 100 Jlg/L except for concentrations detected in
1-9 and SP7-MW-OOI6. Naphthalene concentrations have decreased in WP-5 from 182 Jlg/L
(detected in March 1987) to 27 J.1glL (detected in 1991). The decrease in naphthalene
concentrations in monitoring well WP-5 between 1987 and 1991 suggests that the
naphthalene may be attenuating naturally, probably from aerobic biotransformation.
Additional BNAs (non-PADs) detected in groundwater samples include BEHP detected in
sample SP7-MW-0014 at a concentration of 5.5 JlglL; butylbenzylphthalate detected in
sample SP7-MW-OOI4 at a concentration of 0.3 JlglL; dibenzofuran detected in sample
SP7-MW-0014 at a concentration of 0.5 Jlg/L; and di-n-octylphthalate detected in samples
,.
1-9 and SP7-MW-0014 at concentrations of 0.28 and 0.3 J,lglL. respectively. The
concentrations of these non-PARs were between the method detection limit and practical
quantitation limit. Concentrations of di-n-butylphthalate and butylbenzylphthalate were
-21-
-------
Aulyk
Dale Slllllpled
VOA TO. Compoaads (agll) (1)
A",""",
Beazme
Chloraform
I,2-Dic:hIoroprapaDe
Tolume
Etbylhenzme
Xylezle:s. ToW
P 700
10,000. 10,lXlOb 10,000
NS NS NS
60 4b 0
NS NS NS
10. NS NS
100 NS NS
NS NS NS
100 NS NS
NS NS NS
200c SO-2OOb NS
2000a 200Gb 2000
Sa Sb 5
NS NS NS
l000c 130Gb 1300
300c 300d NS
lSa lSe 0
NS NS NS
SOl: SOd NS
100& IIn> 100
NS NS NS
160000& NS NS
SOOOc SOOOb NS
NS NS NS
NS NS NS
NS NS NS
NS NS NS
NS NS NS
NS NS NS
NS NS NS
NS NS NS
NS NS NS
NS NS NS
Notes:
. Florida Primary DriDkiI1S Water SWIdanI.
b EPA Primary Ma.
c Florida Secondary DriIIkiDg Water StIIIducI.
d EPA Secondary Ma. - l1on-afon:eable guideI1ce values
e Final Aaion Level - fmal Ie8d ICticalevei is eueed if level of JeadJcopper in more 1IwI10 'I.
of the targew:l tap sample$ is greou:r than aaiOl1Ievd(9(kh'l.)
f Value is fCl" Total TrihaJometh.mes .
cO.l2
o.sl
GAl
0.21
<13
21
11
<13
<20.0
6.6B
<2.0
77.600
<:2.0
423B
<3.0
2.,270 B
<1.0
<6.0
4,160B
29,soo
12.3B
2UB
7.2B
79,soo
<2.0
429B
2,290 B
1.1 B
4,490 B
29,700
34.7
<10
<10
11
<10
<10
<10
<10
::'{:}:::::i'i:){:::::I)f':'I::ii:::i:})'i
<10 <10
<10 <10
120 160
100 150
cO.n
COIIIINnll.d~
B . Rading is Ja:s than CRQL
bat grata" IIwI IDl.
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
0.Q321 oms 1
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
NA NA
-------
TABLE U
SUMMARY OF CONS'lTl'tJENJ'S IIEI'ECnD IN GROUNDWATER
SITE 88-3, AIRCRAFT WASBRACK
MONTGOMERY WATSON. 1993
~ ABB,J1orid8
CON'I1NUED
AaalJk J1orid8 EPA EPA s..plelD SP7-DMW-0001 SP7-EB-«IOI SP7-B-GOO1 SP7.FJI..OOO2
Dale S_pIed . DriIIkia& DriaId8& Ma888 Dote CdIed 700 <10 <10 <10 <10
Xyleaes, Toul 10,l)OOa 10,ooob 10,000 <10 <10 <10 <10
PcslicldelPCB TCL Compoaacls (qII) (1)
p,p-DDD NS NS NS <10 410 <..10 <..10
DNA TeL C....poIIIIds (agll) (1)
Bis (2-Etbylhezyl) pbIbaIaIe Cia 4b 0 0,41 0.61 0.3J <10
Di-D-BUlyI Pb1ba/a!e NS NS NS 11 <10 <10 <10
Di-n-oc:tyIpbIba1a lOa NS NS <11 <10 <10 <10
Fluor=e lOa NS NS <11 <10 <10 <10
2-MethylDaphlhalene NS NS NS 0.61 <10 <10 <10
NaphlhaJeae lOa NS NS 0.61 <10 <10 <10
Pbman1bn:lle NS NS NS <11 <10 <10 <10
Total MeIa!s (agIJ) (2)
Aluminum 200c SO-2OOb NS 44B <20.0 <20.0 <20.0
Barium 2000a 2000b 2000 11.1 B <1.0 <1.0 <1.0
Cadmium Sa Sb 5 <2.0 <2.0 <2.0 <2.0
Calci1llD NS NS NS 83,800 45.1 B !2OB 1078
Copper l000c l300b 1300 2.8B 2.28 9.08 <2.0
Iron 300c . 300d NS 11.5 B <1JJ 8.98 7.88
Lead 158 lSe 0 <3JJ <3.0 <3.0 <3.0
MagDeSiwn NS NS NS 3,670 B <30.0 <301) <3OJJ
MaDgmese SOc SOd NS <1.0 <1.0 <1.0 <1JJ
NicIrd 100. l00b 100 <6.0 <6.0 33.8B <6.0
PoIaaium NS NS NS 5,810 <32S <32S <32S
Sodium l60000a NS NS 3O.soo 34,4B 43.2 B <30.0
Zinc: SOOOc SOOOb NS I1.8B 9.0B 68.6 33
Dissolved Me"" (ugll) (2)
Aluminum NS NS NS <20.0 <20.0 NA NA
Barium NS NS NS 10.8 B <5.0 NA NA
Calcium NS NS NS 791YXJ <20.0 NA NA
Copper NS NS NS <2.0 <2.0 NA NA
Iron NS NS NS <1.0 13.6 B NA NA
Magnesium NS NS NS 3,560 B <1.0 NA NA
MaDgmese NS NS NS <1.0 <6.0 NA NA
PoIassium NS NS NS 5,S60 42.2 B NA NA
Sodium NS NS NS 29,900 <3.0 NA NA
Zinc NS NS NS 19.5 B 4.7B NA NA
All samples ana1yzed by Savmnah I..aboraua-ies, Tallahassee, F1orida.
< - 1101 def.eCl
-------
below the Florida Groundwater Guidance Concentration of 10 and 1,400 J.1g/L, respectively
(Tables 2-4 and 2-5). The concentrations of di(2-ethylhexyl)phthalate (DEPH) in samples
SP7-MW-OOI4 and SP7-MW-0016 were above "the proposed Federal Primary MCL of
4 J.1g/L. In addition, the concentration of DEPH in sample SP7-MW-0016 was above the
Florida Groundwater Guidance Concentration of 14 J.1g/L.
1993 Investigation. A total of seven BNAs were detected in the three groundwater and one
duplicate sample (SP7-DMW-0001, SP7-MW-OOI4, SP7-MW-OOI6, and SP7-MW-9016)
collected in the 1993 OU-6/Site SS-3 groundwater investigation. Naphthalene and 2-
methylnaphthalene (PAH compounds) were detected in each sample at concentrations
ranging from 0.6 to 480 J.1glL and 0.6 to 860 mgll, respectively. Total naphthalene
concentrations have decreased in sample SP7-MW-OOI4 from 92 to 3 J.1g/L between 1991
and 1993. Total naphthalene concentrations in sample SP7-MW-OOI6 (1340 J.1g1L) and its
duplicate SP7-MW-9016 (1,290 J.1g/L) exceed the Florida Groundwater Guidance
Concentration of 10 J.1g/L and the 17-770 target level of 100 J.1g/L. Total naphthalene
concentrations have significantly increased in SP7-MW-OOI6 between 1991 and 1993.
Fluorene and phenanthrene, also PAH compounds, were found in SP7-MW-OOI6 and its
duplicate with a maximum concentration of 17 and 8 J.1g/L, respectively.
Bis(2-ethylhexyl)phthalate was detected in all samples excluding the duplicate at a maximum
concentration of 7 J.1g/L. Di-n-butyl phthalate was detected in the samples SP7-DMW-OOOI
and SP7-MW-OOI4 at concentrations of 1 and 0.4 J.1g/L, respectively, and di-n-octyl
phthalate was found at SP7-MW-0014 at 0.2 J.1g/L. The summary ofBNAs detected in 1993
is provided in Table 2-6.
Six TICs were identified in the groundwater samples at Site SS-3.
2.6.3.3 Organochlorine PesticidesIPCBs. 1990 and 1991 Investigations. Groundwater
samples were not previously analyzed for organochlorine pesticideslPCBs in the 1990 and
1991 investigation.
1993 Investigation. Groundwater samples from eight monitoring wells (1-8, 1-9, SP7-MW-
0013, SP7-MW-0014, SP7-MW-0016 (SP7-MW-9016, duplicate), SP7-MW-0017, SP7-
MW-OOI8, and SP7-DMW-0001) were analyzed for OC pesticideslPCBs. The DDT
metabolite, p,p'-DDD was the only detected OC pesticide found in two QU-6/Site SS-3
t'
wells. Samples SP7-MW-0017 and SP7-MW-OOI8 contained detectable concentrations of
0.032 and 0.025 J.1g/L, respectively. These concentrations are estimated because they are less"
-22-
-------
than the CRQL. PCBs were not detected in any samples collected in 1993. The summary of
OC pesticidesIPCBs detected is presented in Table 2-6.
2.6.3.4 Inorganic Compounds. No metals analyses were performed on groundwater during
the 1990 field investigation program conducted by G&M. Total metals analyses were
performed on 1991 samples. Groundwater samples collected in 1991 identified the following
metals as present in all of the monitoring wells including WP-6 and WP-8 (the background
wells): aluminum, barium, beryllium, calcium, chromium, cobalt, copper, iron, magnesium,
manganese, potassium, sodium, thallium, vanadium, zinc, lead, mercury, and arsenic.
Calcium, magnesium, and potassium were detected in the 14 groundwater samples including
the duplicate sample analyzed for TAL metals; however, no groundwater quality standards or
guidelines exist for these metals (Table 2-3). Groundwater samples WP-5, WP-6, WP-8,
WGM-3, SP7-MW-0013, SP7-MW-0014, SP7-MW-90l4 (the duplicate of SP7-MW-0014),
SP7-MW-0017, SP-MW-0018, and SP7-DMW-0001 contained very high concentrations of
total calcium, 1,300,000,8,600,000,2,300,000, 1,700,000,3,000,000, 1,600,000, 1,700,000,
1,800,000, 4,700,000, and 1,800,000 J.lg/L, respectively, in addition to significant
concentrations of many other TAL metals. The sampling logs for all 15 samples indicate that
the samples were turbid when collected. It is possible that the high TAL metal
concentrations, particularly that of calcium, are a result of suspended sediments and thereby
overstate the actual concentrations of the analytes at the site (G&M, 1992). Calcium
concentrati'ons reported for groundwater samples collected in 1991, including the duplicate
sample, ranged from 100,000 to 8,600,000 ~gIL. These concentrations are much higher than
the range of dissolved calcium concentrations (55,000 to 140,000 ~g/L) reported in the
Biscayne Aquifer by Sonntag (1987) except for the calcium concentration of 100,000 ~g/L
detected in sample 1-9.
Mercury was detected in samples WP-6 and WP-8 (the background samples) at
concentrations of 0.20 and 0.98 ~gIL, respectively, which is below the Florida Primary
Drinking Water Standard and Federal MCL for. drinking water of 2 ~g/L for mercury.
Arsenic was detected in samples WP-6 (a background sample), WGM-3, and SP7-MW-0015,
at concentrations of 11,10, and 22 ~gIL which are well below the Florida Primary Drinking
Water Standard and Federal MCL for drinking water of 50 J.lg/L for arsenic (Table 2-5).
Barium was detected in all samples collected, except for sample 1-9, at concentrations
ranging from 16 to 540 J.1.g/L which are well below the Florida Primary Drinking Water
Standard and Federal MCL for drinking water of 2000 J.1.g/L.
-23-
-------
Chromium concentrations were detected above the Florida Primary Drinking Water Standard
and the Federal MCL for drinking water of 100 J1g/L in three of these samples: background
samples WP-6 and WP-8, and in sample SP7-MW-0018 with concentrations of 130, 810, and
110 J1g/L, respectively;
Copper was detected in two samples, WP-8 (a background sample) and SP7-MW-0018, at
concentrations of 87 and 28 J1g/L, respectively, which are below the Florida Secondary
Drinking Water Standard of 1,000 J1g/L and the Federal Action Level of 1,300 J1g/L. Sodium
was detected in all wells sampled at concentrations ranging from 17,000 to 63,000 J1g/L
which were well below the Florida Primary Drinking Water Standard of 160,000 J1g/L.
Lead was detected in all of the monitoring wells except for 1-9 and WGM-6, with
concentrations ranging from 6.1 to 210 J1g/L. Six samples, background samples WP-6 and
WP-8, WGM-3, SP7-MW-0013, SP7-MW-0017 and SP7-MW-0018, contained lead
concentrations which exceeded the Federal Action Level for lead of 15 J1g/L. Additionally,
one of these samples, WP-8 (a background sample); contained lead concentrations above
50 J1g/L. Concentrations of lead detected in groundwater samples WP-6, WP-8, and WGM-3
(210, 29, and 16 J1g/L, respectively), collected in 1991, were higher than concentrations
detected in the same wells sampled in 1987. WP-6, WP-8, and WGM-3 were reported to
have been very turbid or showed high turbidity on the sampling logs. The higher lead
concentrations detected in 1991 may be the result of the suspended sediments and thereby
overstate the actual concentration of lead at the site.
Beryllium was detected in one sample, WP-8 (the background sample), at a concentration of
8.9 J.1g/L which exceeds the Florida Groundwater Guidance Concentration of 5 J1g/L and the
Federal MCL for drinking water of 1 J1g/L. Nickel was detected in one sample, WP-8 (a
background sample), at a concentration of 160 J1g/L, which exceeds the Florida Groundwater
Guidance Concentration and the Federal MCL of 100 J1g/L.. Additionally, the sulfate
concentration detected in sample SP7-MW-0014 (26 J1g/L) and its duplicate, sample
SP7-MW-9014 (27 J1g/L), were below the Florida Groundwater Guidance Concentration of
250 J1g/L and the proposed Federal MCL for drinking water of 250 J.1g/L.
Federal Secondary Drinking Water Regulations establish recommended limits and deal with
the aesthetic qualities of drinking water; however, the FDEP has adopted these standards as
t'
the Florida Secondary Drinking Water Standards and requires that potable groundwater shall
meet these recommended limits. Iron, which is naturally high in the Biscayne Aquifer and.
commonly exceeds the Florida Standard Secondary Drinking Water Standard
-24-
-------
(Sonntag, 1987), was detected in all of the monitoring wells sampled for TAL metals at
concentrations ranging from 340 Jig/L to 260,000 Jig/L which exceeded the Federal
Secondary MCL for drinking water and the Florida Secondary Drinking Water Standard of
300 JiglL (Table 2-5). The Federal Secondary MCL for drinking water and Florida
Secondary Drinking Water Standard for manganese (50 Jig/L) was exceeded in seven
samples, WP-6 and WP-8 (the background samples), WGM-3, SP7-MW-0013,
SP7-MW-0015, SP7-MW-0017, SP7-MW-0018, and SP7-DMW-0001, at concentrations of
120,3,900, 77, 120, 130,62,290, and 140 J1g/L, respectively. Aluminum was detected in all
samples at concentrations ranging from 1,400 to 300,000 JLg/L. The Federal Secondary MCL
for aluminum (50 to 200 Jig/L) was exceeded in all samples, except 1-9. Zinc was detected in
five samples, WP-8 (a background sample), WGM-3, SP7-MW-0014, SP7-MW~9014, and
SP7-MW-0017 at concentrations ranging from 22 to 160 JLg/L. Concentrations of zinc did
not exceed the Florida Secondary Drinking Water Standard and Federal Secondary MCL of
5,000 Jig/L in samples analyzed for this constituent. The total dissolved solids concentration
detected in WP-8 (350 mgll) did not exceed the Florida and Federal Secondary Drinking
Water Standard of 500 mgll.
1993 Investigation. Total (unfiltered) and dissolved (filtered) groundwater samples were
analyzed for TAL metals at locations SP7-MW-0014, SP7-MW-0016, SP7-MW-9016
(duplicate), and SP7-DMW-OOOl. The metals aluminum, barium, calcium, copper, iron,
magnesium, manganese, potassium, sodium, and zinc were detected iIi the filtered
groundwater samples, while the unfiltered groundwater samples also included cadmium,
lead, and nickel. None of the metals detected were above Federal or Florida MCLs.
Groundwater analytical results for total and dissolved metals are summarized in Table 2-6.
Evaluation of dissolved metals results indicate that barium, calcium, magnesium. potassium
and sodium are comparable to the total concentrations detected in the groundwater. Total
barium concentrations ranged from 6.6 to 11.1 Jig/L and dissolved concentrations ranged
from 5.7 to 10.8 Jig/L. Barium values are reported as less than the CRQL. Calcium was
detected in each sample ranging in concentration from 77,600 to 89,400 Jig/L in the total
fraction and 79,000 to 87,200 in the dissolved samples. Total potassium concentrations
ranged from 3,950 to 5,810 JiglL and 3,960 to 5,560 in the dissolved samples. Sodium
values ranged from 29~OOO to 30,500 ~g/L in the total samples and 28,600 to 29,900 in the
dissolved samples. These values are within the range of dissolved inorganics detected in the
Biscayne Aquifer and below the groundwater quality criteria (Table 2-5).
-25-
-------
Cadmium was detected in sample SP7-MW-0016 at a concentration of 3.5 J.1g/L and was not
detected in the duplicate. The result was qualified as estimated because it is below the
CRQL. The unfiltered groundwater samples were also analyzed for cyanide which was not
detected above the detection limit in any sample.
2.6.3.5 Summary Section for Groundwater. Groundwater contaminants consist of
VOC, primarily benzene, xylene, ethylbenzene, and hexanone, and the BNA compounds,
naphthalenes, bis(2-ethylhexyl)phthalate and fluorene. Metals were not detected in
groundwater at levels which exceeds Florida and/or Federal standards. Although some
analytical results for the contaminants identified in groundwater are qualified, all data were
found to be of acceptable quality based on USEP A CLP data validation protocols. Since a
worst case scenario includes discharge of groundwater to the drainage ditch as a surface
water, a comparison of concentrations in groundwater was made in the BRA to the Florida
Surface Water Standard and the Federal Freshwater Ambient Water Quality Criteria. Iron, n-
hexane (TRPH surrogate) and phthalate esters exceeds the Florida Standards, DDD has no
standard and was compared to DDT. The DDD concentrations of 3E-5 mg/L exceed the
DDT standard of lE-6 mg/L but falls below the USEPA Ambient Water Quality criteria
(acute) for DDT of 6E-4 mglL. The summary of constituents detected is presented in
Table 2-6. .
NAPL was observed in previous investigations (1984, 1990, and 1991) at monitoring well
1-9. NAPL was not observed in 1-9 during the 1993 investigation; however, a layer 0.5 feet
in thickness was found in monitoring well SP7-MW-0016.
2.6.4
Sediment And Surface Water Investigations
Sediment and surface water samples were collected from the drainage ditch located
northwest of the site, along the southeast side of Bikini Blvd. Sampling locations for the
1991 investigation are illustrated on Figure 2-2; sampling locations for the current
investigation are illustrated on Figure 2-3. A description of the type and quantity of
compounds detected is presented below. Surface water analysis results are compared to
established Florida Class ill Fresh Water Surface Water Quality Standards and Federal Fresh
Water Quality Criteria for surface water quality presented in Table 2-7. Sediment analytical
results are compared to NOAA ER-L and ER-M sediment screening values in Table 2-8.
,.
Sediment and surface water quality were investigated in conjunction with the OU-6/Site SS-3
investigation, the results of which are summarized in the following sections. The.
contaminants detected in drainage ditch samples may be related to runoff from Bikini
-26-
-------
TABLE 2-7
SURFACE WATER QUALITY CRITERIA
Florida Class ill
Fresh Water
Quality Standards(a)
acute
Federal Fresh
Water Quality
Criteria(b) .
chronic
BNA, Jig/L
PAHs (fotal)
Phenanthrene
Fluroanthene
Pyrene
Phthalate Esters
Bis(2-ethylhexyl )phthalate
Di-n-Butyl Phthalate
PesticidesIPCBs, Jig/L
p,p'-DDD
Metals, Jig/L
Aluminum
Arsenic (fotal)
Barium
Calcium
Copper
Iron
Magnesium
Manganese
Potassium
Sodium
Vanadium
Zinc
0.031, ave.
NS
370
11,000
3.0 (ave)
NS
NS
NS
NS
3980
NS
940
NS
NS
NS
NS
NS
NS
3
NS
NS
O.ool(DDT), NS(DDE)
NS
190
NS
NS
12
NS
NS
NS
NS
NS
NS
47
aa023hom.exl
0.001 (DDT)(max)
11(DDT),105O(DDE)
NS
50
NS
NS
3.9
1000
NS
NS
NS
NS
NS
86
NS
360
NS
NS
18
1000
NS
NS
NS
NS
NS
320
a - Florida Administrative Code, 17 - 302510 April 4, 1993
b - U.S. EPA, 1986, 1991
ave. - average annual flow conditions
NS - No standard established
-------
TABLE 2-8
SUMMARY OF SEDIMENT ANALYTICAL RESULTS
SITE SS-3 AIRCRAFT WASHRACK
GERAGHTY & MILLER, 1991
G&M Sample lD. NOAA NOAA SP7 -SD-OOO I SP7-SD-9001 TR1P BlANK BC-SD~10-
Analyte Sampling Date ER-L 3/ ER-M 41 11/18191 11/18191 11/18191 8/27/1991-
VOl ATII E ORGANIC COMPOUNDS (U!~Ik~ dw)'
Carbon disulfide NS NS 61J 79J 5.0 NA
Methylene chloride NS NS 21J 37 J 5.0 NA
BASFlNElITRAI AND ACID EXTRACfABLE
COMPOUNDS (uplk~ dw):
Benzo(a)anthracc:ne 230 1600 [75] <460 NA <1400
Benzo(a)pyrene 400 2500 [120] [110] NA <1400
Benzo(b )fluoranthene NS NS [300] [290] NA <1400
Benzo(g.h.i)perylene NS NS [120] [130] NA <1400
Benzo(k)fluoranthene NS NS [280] [200] NA <1400
Benzoic acid NS NS [23] J [170]1 NA <6800
bis(2-Ethylhexyl) phthalate NS NS 730 640J NA <1400
Butylbenzylphthalate NS NS <470 [110] J NA <1400
Chrysene 400 2800 <470 [230] NA <1400
2-Chlorophenol NS NS [17] <460 NA <1400
Auoranthene 600 3600 [230] [180] NA <1400
Indeno( 1.2,3-cd)pyrene NS NS [130] [130] NA <1400
4-Methylphenol (p-crcsol) NS NS [65] <460 NA <1400
Phenanthrene 225 1380 <470 [41] NA <1400
Pyrene 350 .2200 [260] [220] J NA <1400
METALS (m~lk\! dw)'
Aluminum NS NS 380J 580J NA 2700
Arsenic 33 85 13 14 NA 2.0
Barium NS NS 4.7 5.7 NA 14
Cadmium 5 9 0.96 1.2 NA <2.1
Calcium NS NS 110000 130000 NA 310000
Chromium 80 145 370J 270J NA 11
Copper 70 390 4.4 4.9 NA 16
Iron NS NS 660 870 NA 1700
Lead 35 110 6100 7400 J NA 11
Magnesium NS NS 340 390 NA 1000
Manganese NS NS 5.1 6.5 NA <29
Mercury 0.15 1.3 0.18J 1.3J NA 0.043
Sodium NS NS 130 190 NA 290
Vanadium NS NS 1.9 2.1 NA 5.7
Zinc 120 270 60 89 NA 27
TOTAL RECOVERABLE
PETROLEUM HYDROCARBONS (uglk:g dw) NS NS 84 120 NA NA
...024bom.w
uglkgdw micrograms per kilogram dry weight
mglkg dw milligrams per kilogram dry weight
NA Not Analyzed
< Analyte was not detected at or above the indicated concentration.
[ ] Value is greater than instrument detection limit but less than practical quantitation limit.
J Positive result has been classified as qualitative.
UJ Analyte was not detected. Classified as qualitative.
U Result bas been classified as undetected.
/ Efiects Range-Low
4/ Effects Range-Median
*BC-SD-OOIO - Boundary Canal Background Sample
-------
Boulevard. Contaminants identified at OU-6/Site SS-3 may be carried to groundwater
discharge areas, such as the drainage ditch, where volatilization or photo oxidation would
occur. Organic compounds entering the groundwater may act as nutrient substrate for the
indigenous microbial population and may stimulate biodegradation of susceptible compounds
along the contaminant pathway. This summary of sediment and surface water investigations
is presented for the purpose of review only. Sediment and surface water and will be fully
evaluated in the investigation of OU-9, Boundary Canal.
2.6.4.1 Volatile Organic Compounds. 1991 Investigation. One sediment sample and a
duplicate were analyzed for VOCs in the 1991 investigation. Two VOCs, carbon disulfide
and methylene chloride, were detected in both the sample and the duplicate. Both
compounds were also detected in the associated trip blank.
The surface water sample collected in the 1991 investigation was not analyzed for VOCs.
Constituents detected in the 1991 sediment sampling are summarized in Table 2-8. Results
for the 1991 surface water sampling are summarized in Table 2-9. The complete analytical
results are included in the investigation report (G&M, 1992).
1993 Investigation. Three sediment samples and two duplicates were collected from the
drainage ditch northwest of the site. The VOCs methylene chloride, acetone, carbon
disulfide, and MEK, and sixteen TICs, were detected in the samples. Methylene chloride and
carbon disulfide were detected in only one sample (SP7 -SD-0003) at concentrations of
2 J..Lglkg and 5 J.1g1kg, respectively. MEK was detected in three samples (SP7-SD-0003, SP7-
SD-0004, and the duplicate) at a maximum concentration of 18 J.1g1kg. Acetone was detected
in all samples at concentrations ranging from 98 J..Lglkg to 220 J.1g1kg. Acetone is related to
the degradation of the isopropanol used in the decontamination process, as discussed in
Section 2.6.2.1. MEK and methylene chloride are common laboratory contaminants that
were detected at less than 5 times the detection limit; thus, they are considered laboratory
contaminants and will be qualified in the data validation process. Details of the data
validation process will be discussed in the QCSR for the RI, which will be submitted at a
later date. A summary of compounds detected in 1993 is presented in Table 2-10.
Surface water samples collected in conjunction with the sediment samples were also
analyzed for VOCs. No VOCs were detected. The summary of VOCs detected in surface
water in 1993 is provided in Table 2-11.
-27-
-------
TABLE 2-9
SUMMARY OF SURFACE WATER ANALYTICAL RESULTS
SITE SS-3 AIRCRAFT W ASHRACK
GERAGHTY & Mll..LER, 1991
Homestead ARB, Florida
G&M Sample I.D. TRIP BLANK SP7-SW-OOOl SP7 -SW -900 1
Analyte (a) Sampling Date 11/18/91 11118/91 11/18/91
Duplicate
VOLA TTI..E ORGANIC
COMPOUNDS (ugfU: BDL BDL BDL
BASEfNEUTRAL and ACID EXTRAcr ABLE
ORGANIC COMPOUNDS (ug/L):
bis(2-Ethylhexyl) phthalate NA 521 [1.0] UI
METALS (ug/L):
Arsenic NA 18 26
Calcium NA 30000 30000
Iron NA 81 88
Magnesium NA 1300 1300
Manganese NA 13 13
Potassium NA 4400 4500
Sodium NA 20000 20000
aa025hom.exl
ug/L
NA
NS
BDL
<
micrograms per liter
Not Analyzed
No Standard
Below Detection Limit
Analyte was not detected at or above the indicated concentration.
Value is greater than instrument detection limit but less than PQL.
Positive result has been classified as qualitative.
Analyte was not detected. Classified as qualitative.
Constituents not detected in any samples are not shown.
[ ]
J
UJ
af
-------
TABLE 2-1.
SUMMARY OF CONS1TI'UENTS DETECTED IN SEDIMENT SAMPLES
SITE ~3, AIRCRAFT WASIIRACK AREA
MONTGOMERY WATSON, 1993
R, II -'v ARB, FIarIda
ADa/yte
NOAA NOAA BC-SD-eI"'.
ER.L ER-M Back8J'oaDd
1991
VOA TCL Compounds (ugIkg) (1)
Ac:ctacc NS NS NA
Ccba1 Disu1fuIc NS NS NA
Methylc:uc QUoride NS NS NA
Methyl Emyl Kaonc (2-Buunme) NS NS NA
Pest.icicWPCB TeL CompclWlds (ugIkg) (1)
Bc:uBHC NS NS NA
Bc:ra-ChJordane NS NS NA
p,p'-DDD 2 20 NA
p,p'-DDE 2 15 NA
p,p'-DDT 1 7 NA
BNA TeL Compounds (ugIkg) (1)
2-CblarophC2101 NS NS <1400
2-MethylDaphtbalcne 65 610 <1400
4-Medtylpbenol (JH:=o1) NS NS <1400
Aecnaphtbcne 150 6SO <1400
Aa:naphtbylene NS NS <1400
Antbrac:ene 85 960 <1400
Beczo(a)Amlua<:ale ZlO 1600 <1400
BCII%O(a)Pyrcne 400 2SOO <1400
BaIzo('o)Fluorautbc:ne NS NS <1400
Bc:azo(g.h.i)Pc:yIC21C NS NS <1400
Bcnzo(k)Fluorautbcne NS NS <1400
Bcmyl Butyl Phthal.ate NS NS <1400
Bis(2-Emy1hexyl) Pbtha1a1e NS NS <1400
Carl>azole NS NS <1400
OuysC21e 400 2800 <1400
Di-n-Butyl Phthal.ate NS NS. <1400
Dibeaz(A,H)Anthra.ceue 400 2600 <1400
Dibc:nzafu1an NS NS <1400
Di-n-Oc:tyl Phthalate NS NS <1400
Fluoxantbcne 600 3600 <1400
F1uo=e NS NS <1400
Indcno(l.2.3-C.D)Pyrcne NS NS <1400
Napbtha1cne 340 2100 <1400 .
Phenanthrene 22.5 1380 <1400
P)=te 350 220 <1400
Metals (mglkg) (2)
Ah1minum NS NS Zloo
Antimaiy NS NS NA
Axsccic 33 IS 2
Barium NS NS 14
C8dmWm 5 9 <2.1
Ca1c:ium NS NS 310.000
Cuamimn 80 145 11
Coba1t NS NS <4.2
Coppa 70 390 161
hon NS NS 1700
Lead 35 110 11
Magnesium NS NS 1000
Manganese NS NS <29
NICkel 30 SO NA
PotasSiwn NS NS NA
Sodium NS NS 290
Vanadium NS NS 5.7
Zinc 120 ZlO Zl
Sample ID
DIlle Calleded
SP7-sD-e882 SP7.sJ).!I4I02 SP7~ SP7-S1).(I084 SP7-SD-9004
3111<'93 3111<'93 3110193 3I18f!13 3110193
DapIIcate Duplicate
190 140 98 110 220
<39 <18 S1 <1A <26
<39 <18 21 <1A <26
<39 <18 151 61 181
<3.9 <4.0 <220 .851 <15
<3.9 <4.0 <220 1.61 <15
210 60 12000 S9 41
330 100 1300 48 291
31B 15B 140 BI 8.8B 22B1
:rr:t~:I:::r:trrr::~m::'rr :r:It:~~::::r::rrr:r:~~m:f::::r:r::::rr~~@::::::r:.
3.6 B <3.0 4.0 B <3.0 <3.0
S86B 673B 8S6B 612B 9088
1Iiil.'ill~l'iliil.lil.l.iililiilillilillll.lllllllililiiii1.'.iiilillililililillliIHililiiiil'ii[dll:lllilllilll:ill:III:IIIIIIIII!illlillli.~i
AU samples analyzed by Savannah l.a1>ommies, Tallahassee. F1arida.
Duods
NA - DOt available 1 - c:stimated quaailiy. Wing B - compound dClCCtCd in an aaoc:iJI1Cd blank
Waste Disposa1 A=. RI- 6/92
(BOllncWy Canal Sed;mcnt Sampling)
Shaded - greater than Background
('2) Data 0113lin~ for In0l"tJ3nic Conmnund~
B - Reading is less than CRQL but gn:au:rthan IDL
E - reported value is esIimatecI due to intezfc:rence
-------
TABLE 2-11
SUMMARY OF CONSTITUENTS DECTECTED IN SURFACE WATER SAMPLES
COLLECTED AT SITE SS-3, AIRCRAFT WASHRACK
MONTGOMERY WATSON, 1993
Homestead ARB, Florida
Florida EPA Sample ID SP7.SW.OOO2 SP7.SW.9002
Surface Water Water Quality Date Collected 3/10/93 3/10/93
Standards Criterion Duplicate
Analyte FAC 17.302.530. (Acute)
VOA TCL Compounds (ugll) (I)
Acetone NS NS ND ND
1.2-Dichloropropene NS 6060 ND ND
Toluene NS moo ND ND
PestlcldeslPCB TCL Compounds (ugll) (I)
p,p'-DDD 0.00059(a) NS ND ND
BNA TCL Compounds (ugll) (I)
Bis(2-Ethylhexyl) Phthalate 3(b) 940(b)
-------
Analyte
VOA TCL Compounds (ugll) (1)
Acetone
1,2-Dichloropropene
Toluene
TABLE 2-11
SUMMARY OF CONSTITUENTS DECTECTED IN SURFACE WATER SAMPLES
COLLECTED AT SITE SS-3, AIRCRAFT W ASHRACK
MONTGOMERY WATSON, 1993
Homestead ARB, Florida
(CONTINUED)
F10rlda
Surface Water
Standards
FAC 17-302.530.
EPA
Water Quality
Criterion
(Acute)
NS NS
NS 6060
NS . 17500
0.00059(a) NS
3(b) 940(b)
3(b) 940(b)
.031(c) 3980
.031(c) NS
II NS
NS NS
50 360
NS NS
NS NS
3.9 18
1000 1000
NS NS
NS NS
100 1800
NS NS
NS NS
NS NS
86 320
PestlcldeslPCB TCL Compounds (ugll) (1) .
p,p'-DDD
DNA TCL Compounds (ugll) (1)
Bis(2-Ethylhexyl) Phthalate
Di-n-Butyl Phthalate
Fluoranthene
Phenanthrene
Pyrene
Metals (ugll) (2)
Aluminum
, Arsenic
Barium
Calcium
Copper
Iron
Magnesium
Manganese
Nickel
Potassium
Sodium
Vanadium
Zinc
Sample ID
Date Collected
All samples analyzed by Savannah Laboratories, Tallahassee, Florida.
< . not detected at specified detection limit (1\ Data Ouallfters for Qnanlc Compounds
NS- no standard J - Estimated Value,
-------
2.6.4.2 Base Neutral/Acid Extractable Compounds. 1991 Investigation. The
sediment sample and the duplicate collected in the 1991 investigation were analyzed for
BNAs. Ten P AH compounds, two phthalates. 2 phenol compounds. and benzoic acid were
detected. Reported concentrations of PAR compounds ranged from 41 J.Lglkg to 300 J.Lglkg.
The highest levels of BNA detected were bis(2-ethylhexyl)phthalate at concentrations of 730
and 640 J.Lglkg in the sample and duplicate, respectively. Bis(2-ethylhexyl)phthalate was also
detected in the surface water sample collected in conjunction with the sediment sample at a
concentration of 52 J.LglL. It was not detected in the duplicate surface water sample.
Analytical results for the 1991 sediment and surface water samples are summarized in
Table 2-8 and 2-9, respectively.
1993 Investigation. Three sediment samples and two duplicates were analyzed for BNAs.
A total of 25 BNA compounds were detected in site samples. Sample SP7-SD-0002.
collected from the same approximate location as the 1991 sample, contained 23 BNA
compounds including all of those detected in the 1991 sample except benzoic acid. Of the 23
detected compounds. 17 are PARs, 4 are phthalates, and 2 are phenols; dibenzofuran and
carbazole were also detected. Concentrations of the P AHs ranged from 10,000 J.Lglkg
(phenanthrene and fluoranthene in SP7-SD-0002) to 120 J.Lglkg (acenaphthalene in
SP7-SD-9OO2). PAR concentrations are generally higher than those reported for the other
classes of BNA compounds. The surface water samples collected in conjunction with the
sediment samples contained low levels (0.1 to 0.2 J.LglL) of three PAH compounds
(phenanthrene, fluoranthene, and pyrene). Two phthalates (di-n-butyl phthalate and
bis(2-ethylhexyl)phthalate) were also detected at levels ranging from 0.2 to 0.3 J.Lg/L. Six
TICs were also reported for surface water samples. Analytical results for the 1993 sediment
and surface water samples are summarized in Tables 2-10 and 2-11, respectively.
Concentrations of P AHs detected in sediments are higher than those detected to date in site
soil samples. Concentrations of the BNAs detected in surface water are generally less than
those detected in site groundwater samples. BNAs were detected in samples both upstream
and downstream of OU-6/Site SS-3.
2.6.4.3 Organochlorine PesticidesIPCBs. Sediment and surface water samples were not
analyzed for organochlorine pesticideslPCBs in the 1991 investigation.
1993 Investigation. No PCBs were detected in sediment samples. The pesticides beta
hexachlorocyclohexane (beta BHC), beta-chlordane, and the DDT metabolites p,p'-DDE,.
p,p'-DDD, and p,p'-DDT were detected in sediment samples. Beta BHC and beta-chlordane
-28-
-------
were only detected in sample SP7-SD-0004 at concentrations of 0.85 and 1.6 J.1glkg,
respectively. The DDT metabolites were detected in all three samples and the two duplicates
at concentrations ranging from 8.8 Ilglkg to 12,000 J.1g1kg. The highest concentrations of
DDT metabolites were detected in sample SP7-SD-0003, collected from a location
downstream of the site. Results for the metabolite p,p'-DDT are qualified as estimated due to
blank contamination. However, as discussed in the QCSR, the blank contamination is a
result of carryover from the previously run sample. Control samples analyzed subsequent to
the blank did not contain p,p'-DDT; thus, the sample results are not considered suspect.
Analytical results for pesticides/PCBs in 1993 sediment and surface water samples are
summarized in Tables 2-10 and 2-11, respectively. DDT and its metabolites have been
observed in soil and sediment samples collected at CERCLA sites throughout the Base.
The DDT metabolite p,p'-DDD was also detected in surface water sample SP7-SW-0003 at a
concentration of 0.022 J.1g/L, below the CRQL. No standards or criteria for the metabolite
p,p'-DDD have been established. The detected concentration is in excess of established
Florida Surface Water Quality Standards for DDT of 0.001 Ilg/L maximum and below
established federal criteria for acute exposure to DDE and DDT (Table 2-7). No other
pesticides or PCBs were detected in surface water samples.
2.6.4.4 Metals and Cyanide. 1991 Investigation. The metals aluminum, arsenic,
barium, cadmium, calcium, chromium, copper, iron, lead, magnesium, manganese, mercury,
sodium, vanadium, and zinc were detected in the sediment sample and duplicate sample
collected during the 1991 investigation. These metals are commonly detected in limestone.
Concentrations of most constituents detected in the sediment samples were below average
carbonate concentrations except for the trace metals, cadmium, chromium, zinc, arsenic,
mercury, and lead, which were above concentrations given for the average carbonate
composition (Hem, 1989).
Concentrations of chromium detected in sample SP7-SD-000I and its duplicate
SP7-SD-9001 exceeded the NOAA ER-L and ER-M values. Sediment sample SP7-SD-OOOI
contained mercury concentrations which exceeded the NOAA ER-L value. Lead
concentrations detected in sample SP7-SD-OOOI and its duplicate, SP7-SD-9001, exceeded
the NOAA ER-M and ER-L values.
The surface water sample and duplicate collected in conjunction with the sediment sampfe
contained arsenic, calcium, iron, magnesium, manganese, potassium, and iron. None of these .
metals was detected in excess of established federal or state surface water quality standards;
-29-
-------
and, therefore, none were identified as compounds of concern in the report of the
investigation (G&M, 1992). No analyses for cyanide were performed in the 1991
investigation. Analytical results for the sediment samples are summarized in Table 2-8;
surface water analytical results are summarized in Table 2-9.
1993 Investigation. Three sediment samples and two duplicate samples were analyzed for
metals. With the exception of mercury, the metals detected in the 1991 sediment sample
were detected in all of the current samples. Nickel, which was not found in the 1991 sample,
was also found in all current sediment samples. Samples SP7-SD-0002 and SP7-SD-0003
also contained antimony. In the absence of background concentrations for metals in
sediment, it is not possible to assess whether OU-6/Site SS-3 has contributed metals
. contamination to the ditch sediments. Surface water samples collected in conjunction with
the sediment samples contained those metals identified in the 1991 sample plus aluminum,
barium, calcium, vanadium, and zinc. Copper was also detected in sample SP7-SD-0002.
None of the metals were detected in excess of established state or federal surface water
quality criteria. Analytical results for sediment and surface water samples are summarized in
Tables 2-10 and 2-11
No regulatory standards currently exist for sediments. However, comparing analytical results
to NOAA Effects Range-Low (ER-L) values, only cadmium, lead, and zinc exceed these
criteria (Table 2-10). The environmental impact evaluation is deferred to the Site SS-3
Baseline Risk Assessment Phase n Report, Section 6.2.1.2.
2.6.4.5 Summary for Surface Water and Sediment. Drainage ditch sediments
contained detectable concentrations of carbon disulfide, methylene chloride,BNAs
(17 PAHs) and DDT-metabolites. The contaminants detected in drainage ditch sediments
may be related to sources other than OU-6/Site SS-3. PARs and metals in particular may be
related to runoff from Bikini Boulevard. Surface water sw:nples contained detectable
concentrations of the P AH compounds phenanthrene, fluoranthene and pyrene. In general,
compounds detected in surface water samples, primarily BNAs, pesticides, and metals, are
lower than those detected in groundwater at OU-6/Site SS-3. Similar concentrations of
constituents were observed in both upgradient and downgradient surface water and sediment
samples.
The contaminants detected in the drainage ditch samples may be related to runoff from Bikmi
Blvd. The contamination present at OU-6/Site SS-3 have demonstrated persistance and.
limited migration since 1984. Hence, the present site condition at OU-6 does not represent a
-30-
-------
significant likelihood to further impact the drainage ditch sediments or surface water.
However, should contaminants be carried via groundwater to discharge areas, such as the
drainage ditch, volatilization or photo oxidation would occur. Organic compounds entering
the groundwater may act as nutrient substrate for the indigenous microbial population and
may stimulate biodegradation of susceptible compounds along the contaminant pathway.
The significant and potential human health and environmental impacts of occurrences of
constituents detected in drainage ditch sediments and surface water will be fully evaluated in
the RI/BRA for Site SD-27, (OU-9) Boundary Canal Investigation.
2.7
SUMMARY OF SITE RISKS
In order to evaluate whether existing or future exposure to contaminated media at OU-6/Site
SS-3 could pose a risk to people or the environment, USAF completed a Baseline Risk
Assessment (BRA) in July 1994 with EPA oversight of this process. This evaluation then
served as a baseline for determining whether cleanup of each site media was necessary. In
the BRA, USAF evaluated site risks for several environmental media. This ROD addresses
the risks attributable to chemicals in the soil and groundwater at OU-6ISite S5-3. Sediment
and surface water will be addressed as part of OU-9, Boundary and Military Canal
investigation. The risk assessment included the following major components: selection of
chemicals of potential concern, exposure assessment, toxicity assessment, risk
characterization, development of remedial goal options, ecological risk, and uncertainties.
The USAF estimated potential site risk in the absence of any future remediation.
2.7.1
Selection -of Chemicals of Potential Concern
Samples collected at OU-6/Site SS-3 indicated that the groun4water contains VOCs, PARs,
TRPH, and metals. Soils at the site contain VOCs and BNAs.
Chemicals detected that are the most toxic and that are anticipated to create the greatest
potential risk were selected as chemicals of potential concern (COPCs). All the detected
constituents were included as COPCs for the risk assessment with the following exception:
Chemicals that are essential human nutrients and constituents that are toxic only at very high
doses (i.e., much higher than those that could be associated with contact at the site) were
eliminated risk assessment.
-31-
-------
TABLE 2-12
CHEMICALS OF POTENTIAL CONCERN
SITE SS-3 (Former SP-7), AIRCRAFT W ASIlRACK AREA
Homestead Air Reserve Base, Florida
Soil
Ground
Water
VOCs
Benzene
Chlorofonn
Ethylbenzene
Methyl ethyl ketone
Methylene chloride
Styrene
Xylenes
x
X
X
X
X
X
X
X
X
BNA's
Bis(2-Ethylhexyl)phthalate
Di(n-octyl)phthalate
Dibenzofuran
Fluorene
n-Hexane (1)
2-Methylnaphthalene
Naphthalene
X
X
X
X
X X
X X
X X
X
Metals
Cadmium
(1) n-Hexane is used as a surrogate for Total Recoverable Petrolewn
Hydrocarbons (TRPH) and Alkane Tentatively Identified
Compounds (TICs).
-------
Inorganic constituents present at concentrations less than twice background concentrations
were excluded from the list of COPCs. Only those constituents for which the maximum
detected concentration was greater than twice the background concentration were retained as
cOPCs.
Inorganic and semi-volatile organics considered to be present in background concentrations
according to the scientific literature for the specific chemical or those chemicals considered
ubiquitous and determined not to be site-related. Although phthalate esters are relatively
ubiquitous in the environment, the presence of these constituents in media at the site may be
due to sampling or laboratory artifacts. Since these phthalates may not be site-related, for
purposes of the BRA only the significant phthalates were considered COPCs.
Based on this evaluation a group of cOPCs was carried through the quantitative risk
assessment for each affected media.
cOPCs for groundwater and soil are shown in Table 2-12.
2.7.2
Exposure Assessment
In the exposure assessment, USAF considered ways in which people could come into contact
with contaminated media under both current and future conditions. A critical step in
assessing the potential risk to public health is to identify the pathways through which
exposure to chemicals could occur. A typical transport pathway consists of four necessary
elements. 1) A source and mechanism of chemical release; 2) an environmental transport
medium; 3) a point of potential contact with the contaminated medium; and 4) an exposure
route (inhalation of vapors, ingestion of groundwater, etc.). All four of these elements must
be present for a pathway to be complete.
Exposure Point Concentration. The exposure point concentration for each contaminant
was derived using the 95 percent upper confidence limit (DCL) on the arithmetic mean as
defined by the following formula:
(- S2 SH)
UCL - x+"2+ "'/0-1
95 - e
where: x
s
arithmetic mean of the log-transformed data
= standard deviation of the log-transformed data
=
-32-
-------
H
=
statistical parameter
Often, with limited data sets, the UCL, is higher than the maximum detected concentration.
If so, the maximum concentration detected was used as the exposure point concentration
rather than the UCLgs. Exposure point concentrations for COPCs are shown in Tables 2-13
and 2-14.
Land Use. Hypothetical future use of the site for residential pwposes is unlikely. However,
for the purposes of the baseline risk assessment, the hypothetical future risks were evaluated
for the possibility of future residential development of the site and installation of a potable
well.
Exposure Scenarios. Potential current risks at the site were evaluated based on a base
worker accessing the site for job related duties. Hypothetical future risks at the site were
evaluated based upon the following exposure scenarios: groundwater ingestion by a
hypothetical future adult resident; and soil exposure by hypothetical future adult and child
residents. Risks were evaluated based on conservative use of Reasonable Maximum
Exposure (RME) assumptions.
The exposure assumptions for each pathway are provided in Tables 2-15 and 2-16. Based on
the exposure point concentrations derived from site data for the chemicals shown in
Table 2-12 and using the exposure assumptions identified in Tables 2-15 and 2-16, EPA
estimated the chronic daily intake (CD I) as~ociated with each exposure pathway and
population combination. The formulas used to calculate the CD! for each pathway are also
provided in Tables 2-15 and 2-16.
2.7.3
Toxicity Assessment
The toxicity assessment evaluated possible harmful effects of exposure to each COPC. A
number of chemicals found at the site, including VOCs, Bis (2-ethylhexyl)phthalate,
cadmium, and lead have the potential to cause cancer (carcinogenic). Slope factors (SFs)
have been developed by EP A's Carcinogenic Assessment Group for estimating lifetime
cancer risks associated with exposure to potentially carcinogenic compounds. These SFs,
which are expressed in units of (mglkg-day)-I are multiplied by the estimated CD! of a
potential carcinogen to provide an upper-bound estimate of the excess lifetime cancer risk
,.
associated with exposure at the intake level. The term "upper bound" reflects the
conservative estimate of the risks calculated from the SF. Use of the approach makes.
underestimation of the actual cancer risk highly unlikely. Slope factors are derived from
-33-
-------
TABLE 2-13
EXPOSURE POINT CONCENTRATIONS FOR GROUNDWATER
SITE SS-3 (FORMERLY SP.7) AIRCRAFT WASH RACK
Homestead Air Reserve Base, Florida
Geraghty & Miller Montgomery Watson
Samples Collected Samples Collected
1990-1991 1993 G&M MW
Constituent [I) No. Samples Mean UCL No. Samples No. Samples UCL(3) Mln Max(3) Mln Max(3)
Collected & A vg. Collected Averaged 1990-93
VOCs (llgIL)
Denzene Recalculated 17 3.8 13.21 3 20 8.54 <5.0 24 <10 70
Ethylbenzene 17 6.6 12 3 20 17.65 <5.0 51 <10 160
Xylenes Recalculated 17 4.4 6.6 3 20 13.15 <5.0 21 <10 150
Chlorofonn Added 17 3 20 2.86 <10 1
DNAs ij1g1L)
Dis(2-Ethylhexyl) phthalate Recalc 17 4 4.8 3 20 15.47 <10 26 <1 7
DI-n-octylphlhalalc 17 7.4 11 3 20 34.93 <10 28 <11 28
Fluorene Recalculated 17 1.6 1.6 3 20 14.41 <10 1.6
-------
TABLE 2.14
EXPOSURE POINT CONCENTRATION FOR SOIL
SITE S8.) (FORMERLY SP.7) AIRCRAFT W ASH RACK
Homestead Air Reserve Base, Florida
Constituent [1)
YQQ~ 1J.u:L!W
Ethylbcnzene
Methylene chloride
Styrene
Xylenes
Methyl Ethyl Ketone Addec
~ (~glkg)
h-Hexane (2) Recalculated
2-Melhylnaphthalene
Naphthalene
Dibenzofuran Added
Geraghty & MUler
Samples Collected
1991
Mean
Montgomery Watson
Samples Collected
1993
No. Samples
Averaged 1990-93
G&M
Mln Max. (3)
MW
Mln Max.13,4)
No. Samples
Collected & A vg.
UCL
No. Samples
Collected
UCL
4 15000 37000 1 5 6E+15 <3400 42,000
4 2500 3600 1 5 1E+1O <3400 3.600
4 4500 11000 1 5 lE+12 <3300 13,000
4 26000 63000 1 5 lE+17 <3400 71.000
4 1 5 7Et{)3 900
4 3,700,000 6,500,000 5 lE+23 860.000 5,900.000 303
4 31000 58000 5 8900 63,000 18
4 17000 33000 5 8E+I0 4800 36,000 37
4 5 lE+17 2,200 4,550 45
u078boID,el
mglkg
~glkg
(I)
mllllgrams per kilogram
mlcrograms per kilogram
Not Detected
Additional data collected In 1993 required some reconstruction of existing database for use in this risk assessment.
Where Indicated, UCLs were recalculated or compounds added.
n-Hexane Is used as a surrogate for TRPH and Alkane TIC's
Maximum used as exposure point concentration when UCL was greater than maximum concentration detected.
No mlnlmum/maximum values presented for Montgomery Watson data since there was only one sample point.
(2)
(3)
(4)
-------
TABLE 2-15
EQUATIONS AND SAMPLE CALCuLATIONS FOR HYPOTHE1'JCAL FUTURE
POTABLE GROUNDWATER EXPOSURE AT
SITE SS-3 (FORMER SP-7), AIRCRAFT W ASHRACK AREA
Homestead Air Reserve Base, Florida
Equation Definition:
GWExD =
ELCR
HQ
where:
AP
BW
CSFo
Cgw
ELCR
EF
GWExD
HQ
IR
Rillo
C~xIRxEF
BW x AP
=
GWExD x CSFo
GWExD
Rillo
=
Averaging period (25,550 days/lifetime [365 days/yr for 70 years] for
carcinogenic effects; 10,950 daysllifetime [365 days/yr for 30 years] for non-
carcinogenic effects (USEPA, 1989a).
Body weight (70 kg) (USEPA, 1991a).
Cancer slope factor for oral exposure (mg/kg-day)-l (Table 3-4 BRA 1994).
Concentration in ground water (mgIL) (lesser of 95 percent upper confidence
limit on the arithmetic mean or the maximum detected concentration) (Table 4-2
BRA 1994).
Excess lifetime cancer risk.
Exposure frequency (10,500 days/lifetime [350 days/year for 30 years]) (USEP A,
1991a). .
Potable ground-water exposure dose (mg/kg-day).
Hazard quotient. .
Ingestion rate - drinking water (2liters/daynUSEPA, 1991a).
Reference dose for oral exposure (mg/kg-day) (Table 3-3 BRA 1994).
Sample Calculation - benzene. cancer effects
GWExD=
ELCR
(0.006 mg/L) x (2 Uday) x (10.500 days/lifetime)
(70 kg) x (25,550 days/lifetime)
= 7.0 x iO-5 mglkg-day
= (7.0 x 10-5 mglkg-day) x (2.9 x 10-2 kg-day/mg)
= 2.0 x 10-6
-------
TABLE 2-15 (continued)
EQUATIONS AND SAMPLE CALCULATIONS FOR HYPOTHETICAL FUTURE
POTABLE GROUNDWATER EXPOSURE AT
SITE SS-3 (FORMER SP-7), AIRCRAFT W ASHRACK AREA
Homestead Air Reserve Base, Florida
Sample Calculation - naphthalene. non-cancer effects
GWExD =
<0.037 mg/U x (2 Uday) x 00.500 daysllifetime)
(70 kg) x '( 10,950 daysllifetime)
1.0 x 10-3 mg/kg-day
=
HQ=
1.0 x 10-3 mglkg-day
4.0 x 10-2 mg/kg-day
=
0.025
Note: This calculation does not include a consideration of the inhalation of volatiles during
showering. This concentration is generally assumed to equal the exposure received from the
ingestion of 2 Uday, the default water ingestion value (Patton, 1991). Further discussion of
this is provided in Section 5.0 of the BRA (Montgomery Watson 1994).
-------
TABLE 2-16
EQUATIONS AND SAMPLE CALCULATIONS FOR SOIL EXPOSURE AT
SITE SS-3 (FORMER SP-7), AIRCRAFT WASHRACK AREA
Homestead Air Reserve Base, Florida .
Equation Definitions:
SExDo = C1 x IR x EF x ED x UCl
BW x AP
SExDd = C1 x SSA x SAR x ABS x EF x ED x UCl
BW x AP
SExDj = !;1 x BR x ET x EF x ED x RF x It-G) x (WlUt)J.x.fu1 (particulates)
BW x AP x Q/C X UC2
or
-<;1 x BR x ET x H x EF x ED x 2 x Dei x Pa x UC~~ (vapors)
BW x AP x Q/C x (3.1416 x alpha x ED x UC3) 112 x UC4
ELCR = (SExDo x CSFo) + (SExDd x CSFa) + (SExDj x CSFj)
HQ
= (SExDJRfDo) + (SExDJRfDa) + (SExD/RfDj)
where:
ABS Dermal absorption efficiency, constituent-specific (from Table 3-2 BRA 1994).
AP Averaging period (equal to ED x 365 days/year for non-cancer effects; 25,550 days [70 years x 365 days/year] for cancer effects) (USEPA, 1989a).
BR Breathing rate (0.83 m3lhour [20 m3/day] for residents [USEPA, 1991 a]; 2.5 m3lhour for base worker [USEP A, 1989b)).
BW Body weight (70 kg for adults; 15 kg for a young child [aged 0 to 6 years)) (USEPA, 1991a). .
Cs Constituent concentration in the soil (mglkg) (maximum detected concentration) (from Table 4~3 BRA 1994).
CSFa Cancer slope factor for dermal exposure, adjusted for absorbed dose (mglkg-day)-I (Table 3-5 BRA 1994).
CSFj Cancer slope factor for inhalation exposure (mglkg-day)-I (Table 3-4 BRA 1994).
CSFo Cancer slope factor for oral exposure (mglkg-day)-I (Table 3-4 BRA 1994).
ED Exposure duration (25 years for base worker; 24 years for an adult resident; 6 years for a child resident [aged 0 to 6 years)) (USEPA, ]99Ia).
EFExposure frequency (350 days/year for residents [USEPA, 1991a]; 12 days/year [I day/month for 12 months per year] for a base worker).
ELCR Excess lifetime cancer risk (unitless).
-------
TABLE 2.16 (continued)
EQUA TIONS AND SAMPLE CALCULATIONS FOR SOIL EXPOSURE AT
SITE SS~3 (FORMER SP.7), AIRCRAFT W ASHRACK AREA
Homestead Air Reserve Base, Florida
ET
H
HQ
IR
RfDa
RfDj
RfDo
SAR
SExDd
SExDj
SExDo
SSA
F(x)
G
RF
UC2
Ut
Q/C
Exposure time (1 hour/day for a base worker; 24 hours/day for residents).
Henry's Law Constant (atm-m3/mol; constituent specific) (Table 3-6 BRA 1994).
Hazard quotient (unitless).
Incidental ingestion rate for soil (50 mg/day for workers; 100 mg/day for an adult resident; 200 mg/day for a child resident [aged 0 to 6 years])
(USEPA,1991a).
Reference dose for dermal exposure, adjusted for absorbed dose (mglkg-day) (Table 3-5 BRA 1994).
Reference dose for inhalation exposure (mglkg-day) (Table 3-3 BRA 1994).
Reference dose for oral exposure (mglkg-day) (Table 3-3 BRA 1994).
Soil adherence rate (1 mg/cm2-day) (USEP A, 1992c).
Soil exposure dose from dermal contact (mglkg-day).
Soil exposure dose from inhalation of particulates or vapors from soil (mglkg-day).
Soil exposure dose from incidental ingestion (mglkg-day).
Exposed skin surface area (3,160 cm2 for adult resident and base worker (USEPA, 1991a); 3,652 cm2 for child resident (aged 0 to 6 years]
(USEPA, 1989b]). '
Unitless function dependent on W/Ut (0.0497) .
Fraction of vegetative cover (unittess) (0)
Respirable fraction of dust (0.036 g/m2-hr)
Unit conversion 2 (3,600 seclhr)
Equivalent thrshold windspeed at a height of 10 meters (12.8 mlsec)
Emission flux per unit concentration (g/m2-sec/kg/m3); calculated as follows:
Q/C = exp(Y + 2.92s(y»-1
Y = O.IOO4X - 5.3466
s(Y) = 0.02685 x (0.25 + (X 2~~3~~~9)2 )
X Natural logarithm of the contiguaous area of contamination in m2 (9.11) (based on three fourths of a three-acre contaminated area
being free of structures)
-------
TABLE 2-16 (continued)
EQUA TIONS AND SAMPLE CALCULATIONS FOR SOIL EXPOSURE AT
SITE SS-3 (FORMER SP-7), AIRCRAFT W ASHRACK AREA
. Homestead Air Reserve Base, Florida
alpha
beta
Dei
Di
Pa
Pt
roe
theta
UC3
UC4
UCs
Convenient collection of variables (cm2/sec); calculated as follows:
Dei x Pa
alpha = Pii+lroe x (I-Pa) x Kd/(UCs x H)j
Soil bulk density (1.5 g/cm3)
Effective diffusivity (cm2/sec); calculated as follows:
Dei = Di(Pa3.33/Pt2) . .
Chemical-specific diffusivity in air (cm2/sec)
Air-fined porosity (unitless); calculated as follows:
Pa = Pt - (theta x beta)
Total soil porosity (unitless); calculated as follows:
Pt = 1 - (beta/roe)
Soil particulate density (2.65 g/cm3)
A verage soil mositure content (0.1 cm3 water/gram Of soil)
Unit conversion 3 (31,500,000 sec/yr)
Unit conversion 4 (0.0001 m2/cm2)
Unit conversion 5 (41 moVatm-m3) (Hwang and Falco, 1986)
-------
TABLE 2-16 (continued)
EQUATIONS AND SAMPLE CALCULATIONS FOR SOIL EXPOSURE AT
SITE SS-3 (FORMER SP-7), AIRCRAFT W ASHRACK AREA
Homestead Air Reserve Base, Florida
Sample Calculation - methylene chloride. cancer effects. base worker (mowin\: scenario):
SExDo =
=
SExDd =
SExDj
(vapor)
ELCR
(3.6 m&!k\:) x (50 malday) x () 2 days/yr) X (25 yrs) x () 0-6 ki:/m\:)
(70 kg) X (25,550 days)
3.0 x 10-8 mg/kg-day
(3.6 m&!ke) x (3.160 cm2) x () m~cm2-daY) x (0.01) x ()2 days/yr) x (25 }Irs) x 00-6 kalme)
(70 kg) x (25.550 days)
=
1.9 X 10-8 mg/kg-day
=
i mOl)
(3.6 mg y 2.5 m3X1~)(12 days)(25yrs)(2)(0.OO75cm2 )(0.28)(0.OO27atm- m3 41 atm - ~
kg A hr day yr sec mol 0.087 cm
g
(70 kg)(25.550day+.6 m'gec } (3.1416{ 0.0012 ::)5 yrs { 3.15xlO' ';; ) r (10" c:' )
=
5.9 x 10-7 mg/kg-day
[(3,0 x 10-8 mg/kg-day) x (7.5 x 10-3 kg-day/mg)] + [(1.9 x 10-8 mg/kg-day) x (7.5 x 10-3 kg-day/mg)] +
[(5.9 x 10-7 mglkg-day) x (1.6 x 10-3 kg-day/mg)]
=
=
1.3 x 10-9
-------
TABLE 2-16 (continued)
EQUATIONS AND SAMPLE CALCULA TlONS FOR SOIL EXPOSURE AT
SITE SS-3 (FORMER SP-7), AIRCRAFT W ASHRACK AREA
Homestead Air Reserve Base, Florida
Sample Calculation - n-hexane. noncancer effects. child resident:
SExDo =
=
SExDd =
=
SExDj =
(Particulate)
HQ
(5.900 m~lq~) x (200 mg/day) x (350 days/yr) x (6 yrs) x (10-6 k~me)
(15 kg) x (2,190 days)
7.5 x 10-2 mg/kg-day
(5.900 melk~) x (3.652 cm2) x (1 m~cm2-day) x (0:01) x (350 days/yr) x (6 yrs) x (10-6 k~m~)
(15 kg) x (2,190 days)
1.4 x 10-2 mg/kg-day
mg m3 hrs days g m m 3
59OO-xO.83-x24-x350-x6yrs x 0.036 2 x(1-0)x(4-1l2.8-) xO.0497
kg hr day yr m - hr sec sec
g
2 sec
15kgx2,190daysx81.6 m kSec x3,6oo-
g hr
m3
=
1.4 x 10-6 mg/kg-day
7.5 x 10-2 melk~-day +
0.06 mg/kg-day
1.2 x 10-6 melka:-day
0.057 mg/kg-day
1.4 x 1 0-2 m~a:-day +
0.06 mg/kg-day
=
aaU8Jhom.wd,.
=
1.5E+00
-------
results of human epidemiological studies or chronic animal bioassays to which animal to
human extrapolation and uncertainty' factors have been applied. The SFs for the carcinogenic
contaminants of concern are contained in Tables 2-17 and 2-18.
Other COPCs, including VOCs. and BNAs, may cause health problems other than cancer.
Reference doses (RIDs) have been developed by EPA for indicating the potential for adverse
health effects from exposure to contaminants of concern exhibiting noncarcinogenic effects.
RIDs, which are expressed in units of mg/kg-day, are estimates of lifetime daily exposure
levels for humans, including sensitive individuals, that are believed to be safe by EP A. RIDs
are derived from human epidemiological studies or animal studies to which uncertainty
factors have been applied (e.g., to account for the use of animal data to predict effects on
. humans). Estimated intakes of COPCs from contaminated media can be compared to their
respective RIDs. The RIDs for the noncarcinogenic contaminants of concern are also
provided in Table 2-17.
2.7.4
Risk Characterization
The centerpiece of the BRA is the risk characterization, which combines the other
components of the evaluation to estimate the overall risk from exposure to site
contamination.
Carcinogenic Risk: For cancer causing compounds, risk is a probability that is expressed in
scientific notation. . For example, an excess lifetime cancer risk of lxlQ-6 means that an
individual has an additional 1 in 1,000,000 chance of developing cancer as a result of
site-related exposure over an estimated 70 year lifetime. EP A has established a target risk
range for DaD and Superfund cleanups of between lxlQ-4 (1 in 10,000) and lxlQ-6.
The formula used for calculating cancer risks is shown below:
Risk = CDIXSF
Where: Risk =
CDI =
SF =
A unitless probability of an individual developing cancer
Chronic daily intake averaged over 70 years (mg/kg-day)
Slope-factor expressed as (mg/kg-day)-l
Potential current total site risk for an on-site workers (e.g. a mower exposed to soils) results
in a total site excess lifetime cancer risk of lE-09.
-34-
-------
TABLE 2-17
REFERENCE DOSES FOR CONSTITUENTS OF CONCERN AT
SITE SS-3 (FORMER SP-7), AIRCRAFT W ASHRACK AREA
. Homestead Air Reserve Base, Florida
Oral RiD Reference Inhalation RID Reference
Constituent (mglkglday) (mg/kgIday)
.YOCs
Benzene NA 5.7E-04 IRIS
Chlorofonn 1.0E-02 IRIS NA IRIS
Ethylbenzene 1.0E-O 1 IRIS 2.9E-Ole IRIS
2-Hexanone NA NA
Methylene chloride 6.0E-02 IRIS 8.6E-Ol IRIS
Methyl ethyl ketone 6.0E-O 1 HEAST 2.8E-O 1 e IRIS
Styrene 2.0E-Ol IRIS NA IRIS
Xylenes 2.0E+OO IRIS NA IRIS
BNAs
Bis(2-ethylhexyl)phthalate 2.0E-02 IRIS NA
Di-n-octylphthalate 2.0E-02 c NA
Dibenzofuran 3.0E-02 IRIS NA
Fluorene 4.0E-02 IRIS NA
n-Hexanea 6.0E-02 IRIS 5.7E-02 IRIS
2-Methylnaphthalene 3.0E-02 d NA
Naphthalene 4.0E-02 IRIS NA
PESTICIDES
DDD 5.04E-04 IRIS NA
INORGANICS
Cadmium(food)b 1.0E-03 IRIS NA
Cadmium (water) 5.0E-04 IRIS NA
References: IRIS, 1993; USEP A, 1992a.
a n-Hexane is used as a surrogate for total recoverable petroleUUl hydrocarbons
and hydrocarbon TICs.
b The RID for food should be used when calculating soil exposure.
c Inferred from Bis(2-ethylhexyl)phthalate.
d Inferred from naphthalene.
e Conversion from RfC.
-------
TABLE 2-18
CANCER SLOPE FACTORS, TUMOR SITES, AND USEPA CANCER CLASSIFICATIONS
FOR CONSTITUENTS OF CONCERN AT
SITE SS-J (FORMER SITE SP-7), AIRCRAFT WASHRACK AREA
Homestead Air Reserve Base, Florida
CSF (mglkglday)-l Tumor site USEPA
Constituent Oral (RcC...CIICC) Inhalation (ReiCO'CllCC) Oral Inhalation ClassiIlCation
~
Benzene 2.9E.{)2 IRIS 2.9E.{)2 . leukemia leukemia A
Chloroform 1.6E.{)3 IRIS 8.1E'{)2 b liver NA B2
Methylene chloride 7SE.o3 IRIS 1.6E.{)3 c: liver hmg, liver B2
St}Tene NA NA NA NA B2
BM&
Bis{2-etbylbexyl)pbthaJate 1.4E.o2 nus NA liver NA B2
~
Cadmium NAP IRIS 6.3E+OO d NA respiratory tract Bl
Lead NA NA NA NA B2
Pesticides
DDD 2.4E.ol IRIS NA liver NA B2
a
b
IRIS. 1992; USEPA,1992a,b. IRIS. 1993
Milligrams per kilogram per day.
Not available.
Not applicable since it is solely carcinogenic by inhalation.
Converted from inhalation unit risk: 8.3E-06
-------
The excess lifetime cancer risk for a hypothetical future adult resident expo.sed to
groundwater at the site was 5E-06. The excess lifetime cancer risk for an adult resident
exposed to soils at the site is 2E-7. The excess lifetime cancer risk for an hypothetical future
child resident is 5E- 7.
Hazards due to Non-carcinogenic Chemicals: For compounds which cause toxic effects
other than cancer, EP A compared the exposure point concentration of a contaminant found at
the site with a reference dose representing the maximum amount of a chemical a person
could be exposed to without experiencing harmful effects. the ratio of the average daily
intake to the reference dose is called a hazard quotient (HQ). The formula for calculating the
HQ is shown below:
Noncancer HQ = CDI/RfD
where: CDI
=
chronicle daily intake
= reference dose
RID
CDI and RID are expressed in the same units (mglkg-day) and represent the same exposure
period (i.e., generally chronic, but also subchronic, or short-term).
The hazard index (HI) can be generated by adding the HQs for all contaminants of concern
that affect the same target organ (such as the liver) within a medium or across all media to
which a given population may reasonably be exposed. In general, EP A considers HI of 1.0
to be the maximum acceptable hazard.
The HI for a current base worker is 3.9E-3.
The non-cancer HI for hypothetical future adult resident exposure to groundwater 3.8E+l is
above the USEP A risk benchmark of 1. The HI for hypothetical future adult resident
exposure to soils (1.9E-l) is below the USEP A risk benchmark of 1. The In for hypothetical
future child resident exposure to soils (1.5) is above the USEP A risk benchmark of 1.
Total Risk. The total site risk for hypothetical future resident exposure is obtained by
summing all of the residential exposures considered in the risk assessment, groundwater
ingestion by an adult resident, soil exposure by child (6 year period) and adult (24 year
period) residents. tbe combined risk across these on-site exposure media (groundwater and
-35-
-------
soils) for a hypothetical future resident results in a total site excess lifetime cancer risk of
6E-6 and an HI 40.2. The carcinogenic total site risk estimate is below the USEP A risk
benchmark of < 1 Q-4 while the In exceeds the USEP A benchmark of <= 1.
. Risk from Lead Exposure. Based on the Integrated Exposure Uptake/Biokinetic (IEUBK)
model for lead, hypothetical future sensitive receptors (children age 0 to 6 years) exposed to
soils at Site SS-8 would not have blood lead levels that exceed 10 micrograms per deciliter
{J,LgldL) (the blood concentration of concern identified by the CDC) assuming exposure to
site concentrations of lead in soil and groundwater.
2.7.5
Development of Remedial Goal Options
Chemicals of concern (COCs) contribute significantly to a use scenario for a receptor that (a)
exceeds a 1 (T4 total carcinogenic risk or (b) exceeds an HI of 1 or (c) exceeds a state or
federal chemical specific ARAR. Chemicals need not be included if their individual
carcinogenic risk contribution is less than lxl0-6 or their non-carcinogenic HQ is less than
0.1.
Remedial Goal Options (RGOs) are risk-based cleanup levels: they are developed by
combining the intake levels to each chemical by a receptor from all appropriate routes of
exposure (Le., inhalation, ingestion and dermal) and pathways within a scenario and
rearranging the site specific CDI equations used in the risk characterization to solve for the
concentration term. RGOs are developed for each medium, each land use, and each receptor
type.
The RGOs are presented here in tabular form and include cleanup levels for the 10-4 , 10-5,
and 10-6 risk levels for each COC, medium, and scenario and the HQs of 0.1, 1, and 10 levels
as well as any chemical-specific ARARs. A summary of the risk-based RGOs are presented
in Tables 2-19 through 2-21.
2.7.6
Ecological Risk Assessment
OU-6/Site SS-3 is located southeast of Bikini Boulevard in the approximate center of
Homestead AFB. Most of the site is occupied by the large concrete and asphalt pavement of
the aircraft wash rack, which is skirted by a maintained lawn of S1. Augustine grass and few
weedy grasses and lawn weeds. The ecosystem compatible with operation of base is not
expected to be the natural ecosystem for South Aori.da. It is unlikely that animals would
-36-
-------
TABLE 2-19
RISK-BASED REMEDIAL GOAL OPTIONS
HYPOTHETICAL FUTURE ADULT RESIDENT
SITE SS-3 (FORMER SP-,), AIRCRAFT WASH RACK AREA
GROUNDW A TER (rogIL)
Homestead Air Reserve Base, Florida
EPA Florida
HAZARD INDEX CARCINOGENIC RISK Maximum Drinking
Contaminant Water
COMPOUNDS 0.1 1.0 10 lE-06 1 E-OS 1E-04 Level(J) Standard(1)
Benzene - - - . - . 0.0029 0.029 0.29 0.005 0.001
Cbloroform 0.037 0.3700 3.7000 0.0532 0.532 5.32 0.1 (a) 0.1 (a)
B is(2-ethyUJexyl)pbthalate 0.073 0.730 7.30. 0.0061 0.061 0.61 0.004 0.006
Ethylbenzene 0.365 3.650 36.500 . . - . .. 0.700 0.700
Xylenes 7.30 73.00 730.00 - - . - - - 10.0 10.0
DI-n-octylphthalate 0.073 0.7300 7.300 - - - - - - NS NS
Auorene 0.146 1.460 14.60 . . . - - - NS 0.010
n-Hexane [a] 0.219 2.190 21.90 - . - - - - NS NS
2-Methylnapblbalene 0.110 1.100 11.00 - - - - - - NS NS
Naphthalene 0.146 1.460 14.60 - - - - - . NS 0.01
Cadmium 0.0018 0.0180 0.1800 . - - - - - 0.005 0.005
. - Not applicable
(a) as Total Trihalomethanes
NS = No Standard
(1) units are mglL
-------
TABLE 2-20
RISK-BASED REMEDIAL GOAL OPTIONS AND FDEP SOIL TARGET LEVELS
HYPOTHETICAL FUTURE ADULT RESIDENT
SITE SS-3 (FORMER SP-7), AIRCRAFT W ASHRACK AREA
SOIL (mg/kg)
Homestead Air Reserve Base, Florida
HAZARD INDEX CARCINOGENIC RISK FDEP
Soli Target Levels Based
COMPOUNDS 0.1 1.0 10 I E-06 IE-OS IE-04 on a Hazard Index or I
Methylene chloride 1,398 13,980 139,800 15.5 155.0 1,550 10,600
Ethylbenzene 2,014 20, 140 201,400 - - - - - - 23,400
Methyl ethyl ketone 1,924 19,240 192,400 - - - - - - 33,000
Styrene 11,094 110,940 1,109,400 - . . - - - NS
Xylenes 11 ,094 11 0!940 1,109,400 - . - - . - 93,400
Dibenzofuran 1,620 16,200 162,000 . . - - - . 2,010
n-Hexane [a] 3,328 33,280 332,800 - - - - . - 30,200
2-Methylnaphthalene 1,621 16.210 162,100 - . - - - - 90,000
Naphthalene 2,161 21,610 216,100 - - - - - - 9,600
- - Not applicable
[a] n-Hexane is used as a surrogate for total petroleum hydrocarbons.
-------
TABLE 2-21
RISK-BASED REMEDIAL GOAL OPTIONS AND FDEP SOIL TARGET LEVELS
HYPOTHETICAL FUTURE CHILD RESIDENT
SITE SS-3 (FORMER SP-7), AIRCRAFT WASHRACK AREA
SOIL (mglkg)
Homestead Air Reserve Base, Florida
HAZARD INDEX CARCINOGENIC RISK FDEP
Soil Target Levels Based
COMPOUNDS 0.1 1.0 10 lE-06 IE-OS lE-04 on a Hazard Index of 1
Methylene chloride 296 2,960 29,600 7.55 75.5 755 3,590
Ethylbenzene 462 4,620 46,200 - - - - - - 6,530
Methyl ethyl ketone 298 2,980 29,800 - - - - - - 20,500
Styrene 1,320 13,200 132,000 - - - - - - NS
Xylenes 1,320 13,200 132,000 - - - - - - 37,900
Dibenzofuran 195 1,950 19,500 - - - - - - 307
n-Hexane [a] 397 3,970 39,700 - - - - - - 4,610
2-Methylnaphthalene 195 1.950 19,500 - - - - - - 190
Naphthalene 260 2,600 26,000 - - - - - - 2,280
- - Not applicable
[a] n-Hexane is used as a surrogate for total petroleum hydrocarbons.
-------
predominantly inhabit or utilize OU-6 in lieu of nearby natural resource areas (Biscayne
National Park to the east, the Everglades to the west, and the surrounding agricultural land).
Because of the developed character of this site, and the Base, it does not provide suitable
habitat for wildlife thus plants and animals are not likely to contact chemicals present at
OU-6/Site SS-3. Site canals are to be more fully addressed in the OU-9 Boundary Canal
assessment.
2.7.7
Uncertainties in the Risk Assessment
The factors that contribute uncertainty to the estimates of exposure concentrations, daily
intakes, and toxicity infonnation also contribute uncertainty to the estimates of risks. These
factors include:
.
Chemicals not included in the risk assessment
Exposure pathways not considered
Derivation of exposure point concentration
Intake uncertainty
Toxicological dose response and toxicity values
.
.
.
.
There are uncertainties associated with summing cancer risks or hazard indices for different
chemicals. The cumulative does ignores possible synergism or antagonism among chemicals
and differences in mechanisms of action and metabolism.
Lead exposure was evaluated with a model that predicts blood levels based on levels
measured in environmental media. Another uncertainty is the faithfulness of this model in
reproducing the actual blood levels. Although any phannacokinetic model is subject to
uncertainties, the predicted blood lead level in children (indicating that lead is not a COC) are
believed to be a reasonable estimate.
2.8
DESCRIPTION OF ALTERNATIVES
The alternatives analyzed for QU-6/Site SS-3, Aircraft Washrack are presented below. These
are numbered to correspond with the numbers in the FS report. The alternatives for site
clean-up are the following:
.
Alternative 1: No Action with Groundwater Monitoring
-37-
-------
.
Alternative 2: Passive LNAPL Recovery, Institutional Controls, and Natural
Attenuation
.
Alternative 3: Passive LNAPL Recovery, Bioremediation/Air Sparging, and
Institutional Controls
.
Alternative 4: Excavation and Off-Site Thermal Treatment, Disposal of
Contaminated Soils, and Natural Attenuation and Institutional Controls
Each alternative includes long-term groundwater monitoring. Alternative 3 is the only
alternative that requires active remediation of the groundwater. These monitoring activities
will be conducted to gauge the effectiveness of the selected remedy.
Except for Alternative 1 all alternatives have the potential to meet USEP A remedial action
objectives and potentially meet the clean-up goals. It is the time, cost, and certainty in
reaching these standards that differentiates the alternatives.
2.8.1
Alternative 1 - No Action with Groundwater Monitoring
The No-Action alternative serves as a "baseline" against which other alternatives are
compared. The No-Action alternative is evaluated as required by the NCP, the regulation
implementing CERCLA. No additional monitoring wells would be required with this
alternative. The existing monitoring wells would t>e sampled semi-annually for 30 years to
monitor groundwater contamination.
Per CERCLA, site reviews would be conducted every 5 years as part of this alternative which
allows COCs exceeding EPA target risk ranges to remain on site. The No-Action alternative
is readily implementable; however, the alternative fails to satisfy all of the requirements
evaluated except for shott-tenn effectiveness. The estimated present worth cost of this
alternative is $700,000 and assumes a duration of 30 years.
-38-
-------
1-
2.8.2
Alternative 2 - Passive LNAPL Recovery, Institutional Controls, and
Natural Attenuation
This alternative consists of:
.
Institutional controls to restrict the placement of potable wells in the contaminated
groundwater near or beneath the site until such time as the protectiveness of the
groundwater is reached. It is estimated that protectiveness (Le., benzene
concentrations in groundwater to be < 1 Ilg/l) will be achieved within a 20 year span
of treatment.
.
Installation of a monitoring/recovery well with an oleophilic bailer approximately
25 feet northeast of SP7-MW-0016.
.
Passive LNAPL recovery at an existing monitoring well (SP7-MW-0016) using an
oleophilic bailer. The final beneficial use/disposal of the recovered LNAPL will be
identified by the Base.
.
A groundwater monitoring program with a five year review until the data confirms
that OU-6 is not a threat to human health or the environments.
There is an estimated, maximum volume of 5,600 gallons of LNAPL at the site. The LNAPL
is the likely source of soil and groundwater contamination. Of specific concern is the
concentration of benzene, 38 Ilg/L, in the one well where LNAPL was observed in 1993.
LNAPL will be removed with two recovery wells. Because this alternative removes the
mobile portion of the potential source of groundwater contamination (Le., LNAPL), the
concentration of benzene is expected to decrease with time more rapidly than with the
No-Action alternative. The recovered LNAPL will be evaluated for possible recycling or
disposal alternatives.
The estimated present worth cost of this alternative is $740,000 and assumes a duration of
20 years.
-39-
-------
2.8.3
Alternative 3 - Passive LNAPL Recovery, Biorernediation/Air Sparging,
and Institutional Controls
This alternative consists of:
.
Passive LNAPL recovery as described in Alternative 2.
.
Implementation of institutional controls to restrict the placement of potable wells in
the contaminated groundwater near or beneath the site until such time as the
protectiveness of the groundwater is reached.
.
A recommended pilot-test of the innovative sparging technology.
.
Groundwater monitoring as described in Alternative 1 with additional sampling to
evaluate the effectiveness of the air sparging system.
.
Installation of 10 air sparging wells within the contaminated groundwater plume.
.
A groundwater monitoring program with a five year review until the data confirms
that OU-6 is not a threat to human health or the environments.
Air sparging and enhanced bioremediation technologies would be implemented after LNAPL
recovery is no longer practicable. Air sparging is a relatively new technology gaining
increased acceptance and application. ~t simply involves injecting air below the contaminant
plume to "strip off" volatile contaminants from groundwater arid soil and enhance natural
bioremediation processes by supplying oxygen to the subsurface. Nutrients and/or special
biological cultures may be added to enhance the bioremediation of nonvolatile compounds.
This alternative was included in the review to meet CERCLA requirements for evaluation of .
innovative technologies. The estimated present worth cost of this alternative is $590,000
. with a 5 year duration.
-40-
-------
T
2.8.4
Alternative 4 - Excavation and Off-Site Thermal Treatment, Disposal of
Contaminated Soils, and Natural Attenuation and
Institutional Controls of Groundwater
This alternative consists of:
.
Institutional controls to restrict the placement of potable wells in the contaminated
groundwater near or beneath the site until such time as the protectiveness of the
groundwater is reached. It is estimated that protectiveness (Le., benzene
concentrations in groundwater to be < I J.1g11) will be achieved within a 5-year span of
treatment.
.
Excavation of soil/rock to meet performance standards, approximately 2,100 cubic
yards and replacement with equal volume of fill material.
.
Off-site thermal treatment and disposal of excavated soil.
.
LNAPL recovery during soil excavation using a skimmer pump.
.
Sending LNAPL to off-site disposal through energy recovery.
.
Disposal of water collected during excavation meeting standards required by the
POTW at a POTW. If the water does not meet performance standards, treatment will
need to occur before disposal.
.
Groundwater monitoring with five year site review until contaminants are at levels
considered protective of human health and the environment, as described in
Alternative 1.
Soil will be excavated to a depth of 6 feet over the inferred aerial extent of soil contamination
(approximately 125 feet by 75 feet). Field screening supported by laboratory analyses will
be conducted to verify that soil meeting the performance standards is encountered at the
bottom and extent of excavation.
An oil skimmer will be employed during the excavation to collect the estimated 5,600
gallons of LNAPL. The soil will be sent to an approved thermal treatment facility. The
LNAPL will be removed to an energy recovery facility and any water generated during
removal operations disposed of through a POTW.
-41-
-------
The sampling and analysis for soils show that the only ocnstituents of concern at Site SS-3
are Naphthalene and 2-Methylnapthalene. In accordance with Capther 62-775 Florida
Administrative Code (F.A.C.), the applicable performance standard for soil cleanup shall be
1 mglkg for P AHs and 50 mglkg for TRPH. Since the lateral and vertical extent of soil
contamination wil be removed to conform to the applicable State standard referred above, no
access and land development restrictions are contemplated to be enacted and/or enforced by
deed.
This alternative also includes semiannual sampling of the site's monitoring wells for two
years to monitor the effect of removing the source (LNAPL) of groundwater contaInination.
The samples would be analyzed for the BNAs and VOAs. Applicable performance standards
and guidance for monitoring of the groundwater include Federal and State groundwater
MCLs (see Table 2-19). Should the monitoring program indiate that contaminant levels have
not naturally attenuated to performance standards described in Chapters 62-550 F.A.C.
(Drinking Water Standards), active groundwater remediation will be contemplated.
Groundwater use restrictions enacted by deed are expected until groundwater at Site SS-3
conforms with the performace standards described in Chapters 62-550 and 62-520
(Groundwater Standards and Classification) F.A.C.
The estimated present worth cost of this alternative if $690,000 with a 5 year duration.
2.9
SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
A summary and comparison of the alternatives are presented in Tables 2-22 and 2-23. The
comparison is based on the nine key criteria required under the National Contingency Plan
and CERCLA Section 121 for use in evaluation of remedial alternatives by EPA. The nine
criteria are as follows:
.
Overall protection of human health and the environment.
Compliance with Applicable or Relevant and Appropriate Requirements.
Long-term effectiveness and permanence.
Reduction of toxicity, mobility, or volume.
Short-term effectiveness.
Implementability .
Cost
State acceptance.
.
.
.
.
.
.
.
-42-
-------
.
Community acceptance.
2.9.1
Overall Protection of Human Health and Environment
Alternatives 3 & 4 meet Remedial Action Objectives for the site and provide protection of
human health and the environment. Alternative 4 provides the best protection through
excavation of the site. While Alternative 2 does not satisfy the statutory preference. for
treatment. this alternative effectively protects human health and the environment through the
utilization of institutional controls that would limit exposure to site contaminants.
Alternative 1 would have no treatment or monitoring mechanism and, therefore, would not
be protective of human health and the environment.
2.9.2
Compliance with Federal/State Standards
There are no ARARs for soil/weathered bedrock contamination at OU-6/Site SS-3. The
ARARs for groundwater contamination at OU-6/Site SS-3 are the state and federal MCLs,
the federal non-zero MCLGs, the state SMCLs, and the Florida 17-770 regulations. Benzene
is the only contaminant found.in the groundwater at OU-6/Site SS-3 at a concentration above
either its state or federal ARAR. Benzene was detected in the groundwater sample collected
in 1993, from the one well that contained LNAPL, at a concentration of 70 J.1g/L, which is
above the state MCL of 1 J.1g/L and the federal MCL of 5 J.1g/L. LNAPL, a likely source for
the benzene, is present in the pore space vadose zone. The more soluble constituents of the
LNAPL and the high percent constituents of the LNAPL composition are slowly dissolving
into the groundwater thereby providing a continuing source of groundwater contamination.
Alternative 3 and 4 meet the ARAR objective for OU-6.
It is possible that the excavated soil at OU-6 may be hazardous waste as defined by toxic
characteristic leaching procedure (TCLP). As TCLP has not bee conducted at this site,
several action specific ARARs may be applied to the Site. These ARARs would include
Resource Concervation and Recovery Act (RCRA) land disposal restrictions (40 CPR 268),
RCRA Standards Applicable to Transporters of Hazardous Waste (40 CPR 263), Department
of Transportation Rules for Transporting of Hazardous Waste (49 CPR 107, 171, 173, 178,
and 179), and Standards for Owners and Operators of Hazardous Waste Treatment, Storage,
and Disposal Facilities (40 CPR 264).
-43-
-------
TABLE 2-22
SUMMARY OF SCREENING OF REMEDIAL ALTERNATIVES FOR SITE SS-3
Alternative
Effectiveness
ImplementabUity
Present Worth
Cost
$ 710,000
1 - No Action with
Groundwater
Monitoring
2 - LNAPL Recovery,
Institutional Controls,
and Natural Attenuation
3 - LNAPL Recovery,
Bioremediationl Air
Sparging, and
Institutional Controls
4 - Excavation and Off-site
Thermal Treatment,
Disposal of
Contaminated Soils,
Natural Attenuation,
and Institutional
Controls.
No reduction of MTVa of contaminants.
Meets USEPA remedial action objectives
(providing groundwater is not considered a
source for potable water) but does not meet
cleanup goals.
Reduces MTV of hydrocarbons in soils and
groundwater. Meets USEPA remedial action
objectives (providing groundwater is not
considered a source for potable water) and
uses deed restrictions to meet cleanup goals.
Reduces MTV of hydrocarbons in soils and
groundwater. Meets USEPA remedial action
objectives and meets cleanup goals. Air
sparging may release harmful vapors to
atmosphere.
Reduces MTV of hydrocarbons in soils and
groundwater. Meets USEPA remedial action
objectives and relies 011 natural attenuation of
benzene in groundwater to meet cleanup
goals.
Includes groundwater monitoring
and 5-year site reviews. Easily
implementable.
Includes deed restrictions,
groundwater monitoring and 5-year
site reviews. LNAPL recovery is
easily implementable.
Uses conventional equipment and
demonstrated technologies. Fouling
of the wells and/or plugging of the
aquifer could occur. Requires pilot-
test; may be moderately difficult to
implement. Could potentially
. remediate site in 3 years.
Uses conventional equipment and
proven methods. Easily
Implementable. Excavation could be
implemented within 6 months; may
require 5 years for natural
attenuation of dissolved benzene.
$ 740,000
$ 590,000
$ 677 ,000
(a-MTV=mobility, toxicity, and volume)
-------
TABLE 2.23
COMPARATIVE ANALYSIS OF REMEDIAL ALTERNATIVES, OU.6/SITE SS-3
Remedial Alternative
Evaluation Criteria
No Action
LNAPL Recovery,
Institutional Controls,
and Natural Attenuation
LNAPL Recovery,
Bioremediationl Air
Sparging, and
Institutional
Controls
Excavation and
Off.Site Thermal
Treatment, Disposal,
Natural Attenuation
and Institutional
Controls
Overall Protection of Human
Health & Environment
o
o
o 0
o 0
o 0
* 0
o 0
Difficult Easy
$590,000 $677,000
Il
Compliance wI ARARs
Il
Il
Long- Tenn Effectiveness and
Pennanence
Il
Reduction of Toxicity,
Mobility, or Volume
Short-Tenn Effectiveness
Il
o
Implementability
Estimated Present Worth
Easy
$710,000
Easy
$740,000
11 Does not meet criterion
o Meets criterion
. Has potential to meet criterion
-------
2.9.3
Long-term Effectiveness and Permanence
Alternative 4 provides the best long-term effectiveness and permanence for OU-6/Site SS-3.
Alternative 3 also provides long-term effectiveness and permanence. However, not as much
as Alternative 4. Alternative 2 utilizes institutional controls, which though effective, would
need to be evaluated during the five-year review. Alternative 1 does not change the
conditions of OU-6; therefore, any contaminants remaining at the site would not be expected
to decrease significantly over time.
2.9.4
Treatment to Reduce Toxicity, Mobility or Volume
Alternative 4 would reduce the mobility of the contaminants through excavation of the
contaminants from the Site and off-site treatment and disposal. Alternatives 2 and 3 both
reduce the mobility, toxicity, or volume of the contaminants while Alternative 2 uses deed
restrictions to meet clean-up goals. Alternative 1 would not provide any additional reduction
in toxicity, mobility or volume of the contaminants.
2.9.5
Short-term Effectiveness
Alternative 1 provides no short term effectiveness and could represent excess risk at the site
Jor thirty years or more.
Alternative 2 provides immediate protection through the implementation of the institutional
controls. Alternative 2 could possibly meet MCLs within 15 to 20 years. This is assuming
that an average of one gallon per day of LNAPL is removed from the well, total recovery at
15 years and then another five years for benzene concentrations to decrease below 1 Jlg/l.
It is anticipated that under Alternative 3, passive LNAPL recovery may be completed within
two years and that the concentration of dissolved benzene will be below the MCL of 1 Jlg/l
within one year of air sparging. The total timeframe for the site to achieve protection is
estimated to be between three and five years.
The excavation associated with Alternative 4 is expected to be completed within one year.
The excavation of soil may impose risks by disturbing the contamination, however, it would
not be expected to pose unacceptable short-term environmental or health hazards, which
could not be controlled. The alternative is expected to achieve attainment five years after
-44-
-------
excavation is complete. Total time for the site to attain protectiveness is estimated at six
years.
2.9.6
Implementability
Alternative 1 and 2 would be easy to implement. Alternative 4 would be easy to moderately
easy to implement. Alternative 3 would be difficult to implement.
2.9.7
Cost
All alternatives are moderately expensive with Alternative 4 having the best opportunity for
long-term effectiveness and permanence given the relatively small differences in cost
between alternatives.
2.9.8
State and Community Acceptance
The no action alternative is not acceptable to the state and community because it does not
actively remediate the groundwater or the source of contamination. Alternative 2 and 3 may
be acceptable to the state and community because it removes the LNAPL at the site.
Alternative 4 has been accepted by the state and community because it offers a permanent
solution and is protective of human health and the environment. Community concerns were
addressed during the public meeting and have been summarized in the "Responsive
Summary" of this ROD. This remedy is acceptable by both the state and community.
2.10
SELECTED REMEDY
Based on consideration of the requirements of CERCLA, the detailed evaluation of the
alternatives and public comments, the USAF in concurrence with the USEP A and the State
of Florida has determined the selected remedy for OU-6/Site SS-3 to be Alternative 4 -
Excavation and Off-Site Thermal Treatment and Disposal of Contaminated Soils. It is the
most reliable and expedient solution identified. It offers a permanent solution that is
protective of human health and the environment. It will serve to protect the groundwater
from further contamination. The NCP (40 CFR 300) views groundwater as a valuable
resource to be protected and restored to beneficial use wherever possible.
-45-
-------
The major components of the selected remedy include:
2.11
.
Excavation of soil/rock to meet performance standard from an approximate 125 ft by
75 ft by 6 ft (2,100 cubic yards) area. The soil is slated for disposal at a RCRA
permitted facility. The facility will use thermal desorption technology to treat the
waste. Fill material will be brought to the site to grade the area.
.
During the excavation an approximate maximum of 5,600 gallons of LNAPL is
expected to be recovered. The LNAPL is slated for energy recovery (Le., recycling)
at an approved facility to be decided. .
.
Groundwater monitoring will be performed at the site for 5 years to show that natural
attenuation will meet performance standards (clean-up levels) applicable to
contaminated groundwater.
.
If after the five year review, the selected remedial action has not restored the
condition of OU-6 to a level that assures protection of human health and the
environment, the EPA, FDEP, DERM, and the Air Force will evaluate the need for
further action.
STATUTORY DETERMINATIONS
Under its legal authorities, EPA's primary responsibility at Superfund sites is to undertake
remedial actions that achieve adequate protection of human health and the environment. In
addition, Section 121 of CERCLA establishes several other statutory requirements and
preferences. These specify that when complete, the selected remedial action for this site
must comply with applicable or relevant and appropriate environmental standards established
under Federal and State environmental laws unless a statutory waiver is justified. The
selected remedy also must be cost-effective and utilize permanent solutions and alternative
treatment technologies or resource recovery technologies to me maximum extent practicable.
Finally, the statute includes a preference for remedies that employ treatment that permanently
and significantly reduce the volume, toxicity, or mobility of hazardous wastes as their
principal element. The selection of Alternative 4 - Excavation and Off-Site Thermal
Treatment of Contaminated Soils at OU-6, Aircraft Washrack meets the statutory
determinations for this site.
-46-
-------
2.12
DOCUMENTATION OF-SIGNIFICANT CHANGES
The PP was released for public comment in November 1994. The PP identified Alternative 4
Excavation and Off-Site Thermal Treatment, Disposal of Contaminated Soils, and Natural
Attenuation and Institutional Controls as the preferred alternative for Remedial Action at
QU-6/Site SS-3. No changes were necessary to the alternative from public input However,
the title of the alternative was expanded from Excavation and Off-Site Thermal Treatment
and Disposal of Contaminated Soils to its present name to represent the alternative more
accurately.
-47-
-------
Homestead Air Reserve Base, Florida
Op~rable Unit No.6, Site 55-3,
Aircraft Washrack Area
Responsive Summary for the
Record of Decision
-------
RESPONSIVENESS SUMMARY
FOR THE
RECORD OF DECISION
The responsiveness summary serves three purposes. First, it provides regulators with
information about the community preferences regarding both the remedial alternatives and
general concerns about Operable Unit No.6, Homestead AFB. Second, the responsiveness
summary documents how public comments have been considered and integrated into the
decision making process. Third, it provides EP A with the opportunity to respond to each
comment submitted by the public on the record.
The Remedial Investigation/Baseline Risk Assessment report and the Proposed Plan for
Homestead AFB OU-6/Site SS-3 were released to the public in June and November 1994,
respectively. These documents were made available to the public in both the administrative
record and an information repository maintained at the Miami-Dade Community College
Library.
A public comment period was held from November 8, 1994 to December 22,1994 as part of
the community relations plan for Operable Unit No.6. Additionally, a public meeting was
held on Tuesday, November 29, 1994, at 7:00 pm at South Dade High School. A public
notice was published in the Miami Herald and South Dade News Leader on Tuesday,
November 22, 1994. At this meeting, the USAF, in coordination with EPA Region N,
FDEP, and DERM were prepared to discuss the investigation, results of the Baseline Risk
Assessment, and the Preferred Alternative described in the Proposed Plan.
No comments were made during the public comment period regarding the preferred remedial
alternative. However, several comments were made during the public meeting which
addressed OU-l, which was also addressed during the public meeting on
November 29, 1994.
------- |