PB94-964056
EPA/ROD/R04-94/185
September 1994
EPA Superfund
Record of Decision:
B and B Chemical Site,
Hialeah, FL,
9/12/1994
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RECORD OF DECISION
B&B CHEMICAL SUPERFUND SITE
HIALEAH, FLORIDA
Prepared by:
u.S. Environmental Protection Agency
. Region IV
Atlanta, Georgia
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DECLARATION FOR THE RECORD OF DECISION
Site Name and Location:
B&B Chemical Site - Hialeah, Dade County, Florida
Statement of Basis and Pu~ose:
This decision document presents the selected remedial action for
the B&B Chemical Superfund Site in Hialeah, Dade County, Florida,
developed in accordance with the Comprehensive Environmental
Response, Compensation and Liability Act of 1980 (CERCLA), as
amended by the Superfund Amendment and Reauthorization Act of 1986
(SARA), and to the extent practicable, the National Oil and
Hazardous Substance Pollution Contingency Plan (NCP), March 8,
1990. The selection of the remedial action presented in this
document is based on the administrative record for the B&B Chemical
~" Site.
The State of Florida, as represented by the Florida Department of
Environmental Protection (FDEP), has been the support agency dur"ing
the development of the remedial investigation/feasibility study
(RIfFS). In accordance with 40 CFR 300.430, as the support agency,
FDEP has provided input during the RI/FS process. Based upon
comments received from FDEP, it is expected that concurrence will
be forthcoming; however, a for.mal letter of concurrence has not
been received.
Assessment of the Site:
Actual or threatened ~eleases of hazardous substances from this
site, if not addressed by implementing the response action selected
in this Record of Decision (ROD), may present an imminent and
substantial endanger.ment to public health, "welfare, or the
environment.
Descriotion of the Selected Remedv:
It is EPA's judgment that the selected remedy will address the
principal threats posed by the environmental conditions at this
site.
The major components of the selected remedy include:
o Natural attenuation;
o Groundwater monitoring in order to verify the
achievement of the maximum contaminant levels (MCLs)
and~
o Institutional controls.
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-2-
Statutory Determination:
The selected remedy is protective of human health and the
environment, complies with federal and State of Florida
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 (or
resource recovery) technology to the maximum extent practicable at
the site. Based on the limited area of low-level groundwater
contaminants present at the site and the fact that these
concentrations, relative to drinking water standards, are low, EPA
concluded that it is currently impracticable to treat the
groundwater effectively. Thus, this remedy does not satisfy the
statutory preference for treatment as a principal element.
This remedy will serve to mi tigate the threat to human heal th
through the natural attenuation of hazardous substances released
from the site. Because this remedy will result in hazardous
substances remaining onsite, a review of the remedial action will
be conducted within five years after the initiation of the remedy
to ensure that the remedy continues to provide adequate protection
to human health and the environment. The review will be performed
every five years thereafter until health-based levels are achieved.
EPA has determined that its response at this site is complete since
no construction is required. The only remedial activity remaining
at the site is groundwater monitoring and institutional controls.
Therefore, the site now qualifies for inclusion on the Construction
Completion List.
~ /2; 1991-
DATE
n L " trr7~
~ j11-
John H. Hankinson, Jr.
Regional Administrator
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-i-
TABLE OF CONTENTS
1.0
Site Location and Description
............. .......... ....
2.0
Site History and Enforcement Activities..................
3.0
Highlights of Community Participation ...................
4.0
Scope of Remedial Action ................................
5.0
Site Characteristics
...... ..... ...... ............... ....
5.1
Geology- and Hydrogeology-...... . . . . . . . . . . . . . . . . . . . . . . . . .
5.2
Surface Water
........................................ .
5.3
Sampling Results
....... ........................... ....
5.3.1
Soil. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . .
5.3.2
Surface Water and SedLment...........
..............
5.3.3
Groundwater.....................
...................
6.0
Summary of Site. Risks. . . . . . . . . . . . . . . . . . . . . .
..............
6.1
Contaminant of Concern
. ...................... ...... ...
6.2
Exposure Assessment Summary
........ ..... ...... ........
6.3
Toxicity Assessment Summary
.......................... .
6.4
Risk Characterization Summary .........................
6.5
Environmental Risk Summary ............................
6.6
Remediation Goals.................
.....................
7.0
Description of Alternatives
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.1
Alternative 1 - No Action
............. ....... .....
7.2
Alternative 2 - Natural Attenuation, Institutional
Controls and Groundwater Monitoring...
7.3
Alternative 3 -
Groundwater Extraction, Physical and
Chemical Treatment and Onsite
Injection Well Discharge...............
PAGE
1
1
6
6
6
6
8
8
8
9
9
18
19
19
22
22
26
26
27
27
27
28
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TABLE OF CONTENTS (CONTINUED)
Paqe
7.4
Alternative 4 - Groundwater Extraction, Physical and
Chemical Treatment and Offsite
Discharge to Surface Water................ 29
7.5
Alternative 5 - Groundwater Extraction, and Offsite
Discharge to a POTW. . . . . . . . . . . . . . . . . . . . . .. 29
8.0
Summary of Comparative Analysis of Alternatives
. . . . . . . . .. 30
8.1
Overall Protection of Human Health
and the Environment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 30
8.2
Compliance with Applicable or Relevant
and Appropriate Requirements ........................... 31
8.3
Short Term Effectiveness. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 33
8.4
8.5
Long Term Effectiveness. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 33
Reduction of Mobility, Toxicity or
Volume Through Treatment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 33
8.6
Implementabili ty ....................................... 34
8. 7 Cost[[[ 34
8.8 CODlIIluni ty Acceptance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 34
8.9
State Acceptance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 34
9.0 Selected Remedy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 35
9.A Natural Attenuation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 35
9 . B Source Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 35
9 . C Groundwater Monitoring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 35
9. C.1 Performance Standards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 36
9 . C. 2 Compliance Testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 36
10.0 Statutory Determination. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 37
10.1 Protection of Human Health and the Environment
........37
10.2 Attainment of Applicable or Relevant
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-iii-
TABLE OF CONTENTS (CONTINUED)
paae
10.3 Cost Effectiveness ....................................38
10.4 Utilization of Permanent Solutions and
Alternative Treatment Technologies .................... 38
10.5 Preference for Treatment as a Principal Element ....... 38
11.0 Documentation of Significant Changes ..................... 39
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Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
-iv-
LIST OF FIGURES
PAGE
Site
Vie ini ty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2
Facility Layout and Former Disposal Areas .......... 3
Generalized Hydrogeologic Cross-Section of the
Surficial Aquifer System, Dade County............... 7
Soil Boring Locations.............................. 10
Monitoring Well Location Map....................... 11
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Table 1
Table 2
Table 3
Table 4
Table 5
Table 6
-v-
LIST OF TABLES
Paae
Concentrations of Organic Contaminants
Detected During RI (1991): Subsurface Soil...........12
Range in Concentrations Detected During FIT
Investigation (1985): Groundwater....................13
Range in Concentrations Detected During RI (1991):
Groundwater. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 16
Contaminants of Concern............................. 20
Major Parameters for Exposure Scenarios for Current
and Future Land-Use Scenarios....................... 23
Evaluation Criteria for Remedial ~ternatives....... 32
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I
Summary of Remedial Alternative Selection
B & B CHEMICAL
1.0
SITE LOCATION AND DESCRIPTION
The B&B Chemical Superfund Site (the B&B Site or the site), is a
four and a half acre site, located at 875 West 20th Street,
Hialeah, Dade County, Florida, in an area of dense light industry.
The site is bounded by West 20th Street to the south, West 8th
Avenue to the east, Florida East Coast Railroad track and West 21st
Street to the north, and to the west by the Dade County Metrorail
Okeechobee Station and parking garage (Figure 1). The
northwest/southeast trending Miami Canal is located within 800 feet
of the southwestern corner of the site.
A gate at the southwest corner of the facility provides access to
the walled compound that comprises the site. The western portion
of the site is used for employee parking. A guard station is
located in this area to control access to facility (Figure 2).
Administrative and manufacturing operations are housed in buildings
located in the southwest and south-central portion of the site.
Warehouse and storage areas for raw materials and finished goods
are located in the eastern and northern portions of the site. Two
tank farms are located in the northeast corner and south-central
portion of the site. However, only the south-central tank farm is
currently in use. Approximately four tanks are located in each
area, ranging in capacity from 5,000 to 10,000 gallons each. The
areas surrounding the buildings and tank farms, as well as the
parking area, are covered by either asphalt or concrete pavement.
The southeast corner of the site is unpaved and covered with gravel
and grass. A storm drain system, consisting of infiltration trench
drains, allows percolation of storm water runoff into the water
table. The existing storm drain system is not connected to the
municipal drainage system.
Ground elevation differences are slight. While a maximum elevation
of seven and a half feet above mean sea level (amsl) is found along
the eastern boundary of the site, the ground surface slopes to a
minimum of five feet amsl near the northwestern corner of the site.
The south-central area is higher than inunediately surrounding
areas.
2.0
SITE HISTORY AND ENFORCEMENT ACTIVITIES
B&B Tritech, Inc., f/k/a, B&B Chemical, Inc. (B&B), was
incorporated in the State of Florida in 1953 and began construction
of the Hialeah facilities in 1959. Since its initial construction,
the site has expanded to its current size through a series of
additions. Prior to completion of construction in early 1963, its
products were mixed in Atlanta, GA. Products were delivered to the
B&B facility in Hialeah, or directly to the B&B customers. B&B
began mixing products at the Hialeah facility in early 1963 and
gradually increased its product line. Chemicals and other products
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LOCATION
SOURCE:
USGS 7 1/2 MINUTE SERrES
HIALEAH QUADRANGLE,
DADE COUNTY, FLORIDA, 1988
FIGURE 1
SITE VICINITY
BBB CHEMICAL SITE
-2-
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known to have been used by the facility include a variety of
solvents, polishes, detergents, oxidizing agents, corrosive
inhibitors and metal cleaners.
In the mid-1970's, Dade County Department of Resource Management
(DERM) inspectors documented the presence of wastewater residues in
soakage pits at the site. Subsequent to this, the Department
issued a Cease and Desist Order, related to the wastewater
discharge to the soakage pits. In May 1976, B&B put a wastewater
pretreatment system into operation. In the course of a 1979 area-
wide groundwater study conducted for DERM, two samples were taken
from irrigation wells located on the B&B Site. Analytical data
from these samples indicated the presence of trans- 1,2-
dichloroethylene, tetrachloroethylene, chlorobenzene, 1,1-
dichloroethane, vinylidene chloride and trichloroethylene. In
September 1981, construction workers installing a potable water
line immediately south of the B&B Site experienced skin irritation.
Analytical data from a groundwater sample collected from the ditch
indicated the presence of phenol, trichloroethylene,
tetrachloroethylene, vinylidene chloride, trans-1,2
dichloroethylene and cis-1,2 dichloroethylene. During the
construction of the Metrorail track immediately south of the B&B
Site in June 1982, workers also complained of skin burns, while
working in trenches. A soil sample taken from the trench was
analyzed and, through gas chromatography, was found to be similar
to a B&B product. In October 1983 DERM issued an Administrative
Order, directing B&B to develop plans for a groundwater monitoring
system. DERM filed a civil suit against B&B in November 1984 for
the substantial delay in submitting the requested groundwater
monitoring plan.
In August 1985, DERM requested that EPA investigate conditions at
the site. EPA obtained a warrant from the Federal District Court
in Miami to install monitoring wells and sample groundwater and
soil. Results of the EPA-funded investigation were documented in
the July 1986 report entitled, "Geologic and Sampling Investigation
Report: B&B Chemical Company, Hialeah, FL." Subsequently, EPA used
the findings of this report to compute an Hazard Ranking System
(HRS) score of 35.35 for groundwater at the site.
In February 1986, a separate investigation was conducted at the
location of the former Crown Paint, Inc. and Fullerton Metals,
Inc., currently the location of the Dade County Okeechobee station
and parking garage. The properties, located immediately east of
the B&B Site and acquired by Dade County through eminent domain in
1981, were found to contain approximately 120 drums of paint waste.
Most of the drums were reported to be in good condition; however,
some have either rusted or expanded, breaking the containers. Yet
others had been tipped over, spilling their contents onto the
ground. A removal action was completed in January 1984.
Subsurface soil and groundwater samples were collected from
locations in and around the perimeter of the Metrorail parking
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-9-
land surface (bls) at 11 locations (Figure 4). The locations of
the borings were pr~arily selected on the basis of the
descriptions of the former soakage pits and other disposal areas
contained in the DERM inspector's reports. Two soil samples were
collected for analysis from each soil boring. Generally a sample
was collected from above the water table (2 to 4 feet bls) and
another sample from below the water table (12 to 14 feet bls).
Seven of the 11 soil borings were located within the south-central
area of the site and targeted the area of the former chemical
septic tank, former rinse water bunker, vehicle wash area and
soakage pits.
With the exception of trace amounts of volatile compounds detected
in the deep sample taken in the vicinity of the eastern tank farm
area, the eastern, western and northern areas were generally free
of contaminants (Table 1). This is in contrast to the south-
central part of the site, where the majority of soil borings
encountered organic contaminants. The highest concentrations of
both volatile and semivolatile contaminants were found in the deep
. samples (Table 1). The soil borings that targeted the vehicle wash
facility, former rinse water bunker and chemical septic tank area
encountered significantly higher organic contaminants.
Some of the subsurface soil organic contaminants also found in the
site's groundwater are chlorobenzene, toluene, 1,2-dichlorobenzene,
1,3-dichlorobenzene, 1,4-dichlorobenzene, 2-methylnaphthalene,
xylene, ethyl benzene, benzene and phenol.
With the exception of the chromium detected in both the deep and
shallow sample from the vehicle wash facility area, inorganic
analytes were not found at elevated concentrations in any of the
soil borings.
5.3.2 SURFACE WATER AND SEDIMENT
Surface water samples were collected from the onsite water runoff
collection and infiltration system. Sufficient amounts of sed~ent
were not present in the inlets to permit sampling.
No contaminants were detected in any of the surface water samples
collected at the site.
5.3.3 GROUNDWATER
Twenty seven on- and off~site groundwater monitoring wells were
sampled during the 1991 RI and subsequent rounds of groundwater
sampling (Figure 5). Of these groundwater monitoring wells, 20
were installed during the 1985 Field Investigation Team (FIT) study
and seven during. the 1991 RI.
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LEGEND
8-8-04 -BORE: HOl.Ł LOC~TION
AND DESIGN~110N
SOIL BORING LOCATIONS
B & B CHEMICAL RI
HIALEAH. FLORIDA
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Table 1
CONCENTRATIONS OF ORGANIC CONTAMINANTS DETECTED DURING RI (1991)
SUBSURFACE SOIL
B&B CHEMICAL NPL SITE
Shallow Soil
(2 - 4 feet) (1)
Range (mg/kg)
Deep Soil
(12 - 14 feet)
Range (mg/kg)
South-central Area (4)
VOCs (2)
SVs e)
0.004 - 54.4
0.130 - 78.6
0.18 - 34.6
0.21 - 138.5
Eastern Area ( 5)
VOCs
SVs
0.14
ND
0.49
ND
Western Area(6)
VOCs
SVs
ND
ND
0.03
ND
Northern Area ( 7 )
VOCs
SVs
ND
ND
ND
ND
(1) Depth of soil sample in feet below ground surface
(2) Total volatile organics, excluding the common lab contaminants
methylene chloride and acetone
(3) Total semivolatile organic compounds, excluding esters of
phthalates
(4) Soil borings B-04, B-08 through B-13 and B-14
(5) Soil boring B-01
(6) Soil boring B-06
(7) Soil borings B-02 and B-03
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1985 FIT Investigation
During the 1985 FIT investigation, the highest concentrations of
groundwater contaminants were found in the shallow (7 to 10 feet
bls) and intermediate (10 to 25 feet bls) depth monitoring wells,
located in the south-central portion of the site (Table 2).
Volatile organic compounds were the principal contaminants
detected. In addition, the tentatively identified organic
compounds were significant contributors to the organic contaminant
fraction in the groundwater. Lower concentrations of organic
contaminants were found in the deep (40 to 75 feet bls) monitoring
wells. .
The inorganic analytes cadmium, chromium and lead were found at
higher concentrations in the western part of the site (Table 2).
An exception is the chromium found in the deep well located in the
south-central part of the site where chromium was found at 210 ppb.
This well is discussed further below.
1991 RI
The groundwater sampling for the 1991 RI occurred thirty two months
after start-up of the groundwater recovery and treatment system.
At this time, a minimum of 37 million gallons of groundwater is
reported to have been recovered by a single 20-foot recovery well,
located in the south-central portion of the site.
The highest concentrations of volatile organic contaminants
detected were found in the shallow ( 7 to 20 feet bls) wells,
located in the south-central portion of the site (Table 3).
Tentatively identified compounds were also found to be present at
this location and at significantly higher concentrations, as
compared to those compounds on the target compound list. Organic
compounds found to be marginally above State of Florida or federal
MCLs during the 1991 RI were vinyl chloride and benzene. Inorganic
contaminants above MCLs were cadmium, chromium and lead. These
analytes too were marginally above MCLs.
September 1992 Groundwater Monitoring
Four weeks after EPA issued the initial Proposed Plan and five
weeks after Hurricane Andrew, EPA resampled the site's groundwater
monitoring wells in late September 1992 and had the samples
analyzed for VOCs and metals. AI though there is no record of total
rainfall at the Miami-Dade Sewer and Water Authority's rain gauge
on the day of Hurricane Andrew's landfall, 3.3 inches were recorded
the following day. This translates to approximately 400,000
gallons of rain falling within the site's walled compound. A
significant volume of rain water probably entered the storm drain
system, possibly flushing the contaminants present in the soil
located in the south-central part of the site (Section 5.3.1).
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TABLE 2
CONCENTRATIONS OF CONTAMINANTS DETECTED DURING FIT INVESTIGATION (1985)
GROUNDWATER
B&B CHEMICAL NPL SITE
Shallow Wells
(7 - 10 feet) e)
Range (ug/L)
Intermediate Wells
(10 - 25 feet)
Range (ug/L)
Deep Wells
(40 - 75 feet)
Range (ug/L)
VOCs ( 2)
SVs e)
TICs(4)
Cadmium
Chromium
Lead
VOCs
SVs
TICs
Cadmium
Chromium
Lead
VOCs
SVs
TICs
Cadmium
Chromium
Lead
South-central Area
320
93
710
4
10
4
14 - 423
57 - 96
930
ND
16 - 25
2.6 - 3.4
14
80
240
ND
210
7
Eastern Area
ND
ND
ND
4.5
ND
3.4
Western Area
4.9
9.9
ND
40
27 - 240
10 - 41
1.4 - 12.1
14
ND
ND
15 - 20
7 - 23
4.5
ND
ND
ND
11
2.6
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TABLE 2 (continued)
CONCENTRATIONS OF CONTAMINANTS DETECTED DURING FIT INVESTIGATION (1985)
GROUNDWATER
B&B CHEMICAL NPL SITE
Shallow Wells
(7 - 10 feet)(l)
Range (ug/L)
Intermediate Wells
(10 - 25 feet)
Range (ug/L)
Deep Wells
(40 - 75 feet)
Range (ug/L)
Northern Area
VOCs
SVs
TICs
Cadmium
Chromium
Lead
ND
28
290
ND
ND
ND
13
ND
ND
ND
25
3 - 5
5
ND
ND
ND
ND
ND
Backaround(5)
VOCs
SVs
TICs
Cadmium
Chromium
Lead
1.5
ND
ND
. ND
ND
ND
2.1
ND
ND
4
ND
ND
(1) Depth of well screen in feet below ground surface
(2) Total volatile organics, excluding the common lab contaminants methylene chloride and
acetone
(3) Total semivolatile organic compounds, excluding esters of phthalates
(4) Total tentatively identified and unidentified compounds
(5) Intermediate and deep data from wells MWS-13 and MWD-14, respectively
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-16-
TABLE 3
CONCENTRATIONS OF CONTAMINANTS DETECTED DURING RI (1991)
GROUNDWATER
B&B CHEMICAL NPL SITE
Shallow Wells
(7 - 20 feet) e)
Range (ug/L)
Intermediate Wells
(35 - 55 feet)
Range (ug/L)
Deep Wells
(75 - 105 feet)
Range (ug/L)
South-central Area
VOCs ( 2 )
SVs e)
TICs (4)
Cadmium
Chromium
Lead
2 - 87
5 - 7
160 - 760
ND
21 - 55
6 - 8
3
ND
ND
ND
ND
5
2 - 12
ND
10
ND
11 - 19
ND
Eastern Area
VOCs
SVs
TICs
Cadmium
Chromium
Lead
ND
ND
ND
ND
12
ND
3 - 8
18 - 73
10
ND
55 - 120
4 - 30
Western Area
VOCs
SVs
TICs
Cadmium
Chromium
Lead
ND
ND
9
5
11 - 12
11 - 13
3 - 7
11
20
9
4
5
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-11-
TABLE 3 (Continued)
CONCENTRATIONS OF CONTAMINANTS DETECTED DURING RI (1991) .
GROUNDWATER
B&B CHEMICAL NPL SITE
Shallow Wells Intermediate Wells Deep Wells
(7 - 20 feet) (35 - 55 feet) (75 - 105 feet)
Range (ug/L) Range (ug/L) Range (ug/L)
Northern Area
VOCs 1 - 2 ND
SVs ND ND
TICs 180 ND
Cadmium ND ND
Chromium 13 - 27 9
Lead 5 - 8 8
Backaround(5)
VOCs ND 4 2
SVs ND ND 20
TICs ND 10 10
Cadmium ND ND ND
Chromium ND 22 ND
Lead ND ND ND
(1) Depth of well screen in feet below ground surface
(2) Total volatile organics, excluding the common lab contaminants methylene chloride and
acetone
(3) Total semivolatile organic compounds, excluding esters of phthalates
(4) Total tentatively identified compounds
(5) Shallow, intermediate and deep data from wells MWS-03, MWM-26 and MWF-26, respectively
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-18-
Groundwater contaminants were observed to rise primarily in the
shallow (7 to 10 feet bls) and intermediate (10 to 25 feet bls)
monitoring wells located in the south-central port of the site, as
well as those wells located immediately south and southeast of the
site. Appendix A contains tables summarizing the groundwater
monitoring data, starting with the March 1991 RI and ending with
the January 1994 round. The same appendix contains summary plots
of total VOC concentrations for upgradient, south-central and
regionally downgradient monitoring well clusters.
As may be seen from the tables and plots presented in Appendix A,
the trace concentrations of VOCs detected in the upgradient wells
declined to near or below detection limits during September 1992.
In contrast, the shallow and intermediate wells located in the
south-central and regionally downgradient well clusters increased
considerably. Maximum contaminant levels were exceeded for vinyl
chloride, benzene and chlorobenzene.
The inorganic analytes cadmium, chromium and lead were found to be
marginally above MCLs during the September 1992 sampling. In each
case, prior or succeeding sampling of the well found in exceedence
did not confirm the presence of the analyte.
1993-1994 Groundwater Monitoring
Following the September 1992 round of groundwater sampling, three
subsequent rounds of sampling took place, ending in January 1994.
Although concentrations declined significantly, relative to the
September 1992 round, the wells located in the south-central part
of the site had detectable concentrations of volatile and
semivolatile organic compounds. With the exception of vinyl
chloride, the contaminants detected were below MCLs. The shallow
south-central area wells contained tentatively identified compounds
at concentrations two orders of magnitude above the concentrations
found in the upgradient wells.
As was the case in previous sampling rounds, the inorganic analytes
cadmium, chromium and lead were present sporadically and at
marginal concentrations. As was mentioned above, since 1985 the
deep well located in the south-central part of the site has
exceeded the chromium MCL of 100 ug/L on three out of the six times
it was sampled. As a result of turbidity measurements made on the
well in 1994 and observations made during well purging, the
elevated chromium is believed to be the product of well-
construction artifact.
6.0
SUMMARY OF SITE RISKS
CERCLA directs EPA to protect human health and the environment from
current and potential exposure to hazardous substances at the site.
In order to assess the current and potential risk from the site, a
baseline risk assessment was conducted. This assessment evaluated
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-19-
the potential risk posed by the site without the benefit of any
future remediation. Results of the risk assessment are contained
in the Final Baseline Risk Assessment (BRA) report, October 1992
and the May 1994 addendum to the BRA. The BRA considers
environmental media and exposure pathways that could result in
unacceptable levels of exposure now or in the foreseeable future.
Data collected and analyzed during the RI and subsequent rounds of
groundwater sampling provided the basis for the risk evaluation.
6.1
CONTAMINANTS OF CONCERN
Based on soil sampling results from the 1991 RI and the update to
the 1992 Risk Assessment using the January 1994 groundwater data,
the risks associated with the site are within EPA's discretionary
risk range, discussed below in Section 6.4. The risk associated
with exposure to the site's ~roundwater, however, is greater than
EPA's goal of less than 10-. During the 1992-1993 groundwater
monitoring period, State of Florida and federal MCLs were exceeded
for vinyl chloride, benzene, chromium and chlorobenzene. Table 4
presents those groundwater contaminants which exceeded MCLs during
this monitoring period and the frequency with which the
contaminants were detected.
6.2
EXPOSURE ASSESSMENT SUMMARY
Whether a contaminant is actually of concern to human health and
the environment depends upon the likelihood of exposure, e. g. ,
whether the exposure pathway is currently complete or could be
complete in the future. A complete exposure pathway (a sequence of
events leading to contact with a contaminant) is defined by the
following four elements:
o
A source and mechanism of release from the source;
o
A transport medium (e.g., groundwater, air, etc);
The presence or potential presence of a receptor at the
exposure point; and
o
o
A route of exposure (e.g., ingestion, inhalation, dermal
absorption, etc)
If all four elements
complete.
An evaluation was undertaken of all potential exposure pathways
which could expose human receptors to the various contaminant
sources. All possible pathways were first hypothesized and
evaluated for completeness using EPA criteria. One current
potentially complete exposure pathways and three future exposure
pathways remained after screening. The current pathways represent
are present,
the pathway
is
considered
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-20-
TABLE 4
CONTAMINANTS OF CONCERN: GROUNDWATER1
B&B Chemical National Priorities List Site
Contaminant
Ranqe of Concentrations
Vinyl Chloride
1.3 - 14.0
Benzene
3.0 -
8.0
Chlorobenzene
110 - 140
130 - 210
Chromium
Frequency of Detection
9/27
2/27
2/27
2/27
State/Federal MCL (ppb)
1 ppb ( 2 )
1 ppb ( 2 )
100 ppb (2,3 )
100 ppb (2,3)
(1) Contaminants of concern selected on
during 1992-1994 monitoring period.
(2) State of Florida MCL
(3) Federal MCL
exceedences of federal and State of Florida MCLs
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-21-
exposure pathways which could exist under current site conditions,
while the future pathways represents exposure pathways which could
exist if the current exposure conditions change. The current
exposure pathways were developed for the Baseline Risk Assessment.
Exposure by each of these pathways was mathematically modeled using
generally conservative assumptions.
The following pathways were evaluated under current
conditions:
land-use
Exposure of onsite workers to contaminants in surface soil
through incidental ingestion and dermal contact
The following pathways were evaluated under a future land-use
conditions:
o
o
Exposure of onsi te construction workers to contaminants in
surface and subsurface soil through incidental ingestion,
dermal contact, and to contaminants in air (dust vapor) through
inhalation;
o
Exposure of trespassers to contaminants in surface soil
through incidental ingestion and dermal contact; and
o
Exposure of onsite residents to contaminants in groundwater
through ingestion, dermal contact and inhalation
The exposure point concentrations for each of the contaminants of
potential concern and the exposure assumptions for each pathway
were used to estimate the chronic daily intakes for the potentially
complete pathways. The chronic daily intakes were then used in
conjunction with cancer potency factors and noncarcinogenic
reference doses to evaluate risk.
The groundwater at the B&B Site currently conta~ns concentrations
of site-related contaminants at levels which may pose a risk to
human health, if the groundwater were to be used for human
consumption. Exceedences of MCLs have been observed for a number
of analytes over the past two years. Locally the Biscayne aquifer
is not currently being used as a source of potable water; however,
the Miami-Dade Water and Sewer Authority produces water from the
Miami Springs/preston wellfields, located less than a mile from the
site. This wellfield yields an average of approximately 140
million gallons per day. The site lies within the cone of the
depression caused by groundwater pumpage from this wellfield. Due
to the area-wide groundwater contamination, groundwater produced by
this wellfield is treated by air stripping of volatile organic
contaminants, prior to distribution. Semivolatile organic and
inorganic contaminants are not treated.
The major assumptions made regarding exposure frequency and
duration, used to estimate risk under the various future land-use
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-22-
scenarios are presented in Table 5.
6.3
TOXICITY ASSESSMENT SUMMARY
Toxicity values are used in conjunction with the results of the
exposure assessment to characterize site risk. EPA has developed
critical toxicity values for carcinogens and noncarcinogens.
Slope factors (SF) have been developed by EPA's Carcinogenic Risk
Assessment Verification Endeavor Workgroup for estimating excess
lifetime cancer risks associated with exposure to potentially
carcinogenic contaminants. SFs are derived from the results of
human epidemiological studies or chronic animal bioassay to which
animal-to-human extrapolation and uncertainty factors have been
applied. SFs, which are expressed in units of (mg/kg/day)-l, are
. multiplied by the estimated intake of a potential carcinogen, in
mg/kg/day, to provide an upper-bound estimate of the excess
lifetime cancer risk associated with exposure at an intake level.
The term "upper bound" reflects the conservative estimate of the
risk calculated from the SF. Use of this conservative approach
makes underestimation of the actual cancer risk highly unlikely.
Reference doses (RfDs) have been developed by EPA for indicating
the potential for adverse health effects from exposure to
contaminants exhibiting noncarcinogenic effects. RfDs, which are
expressed in units of mg/kg/day, are estimates of lifetime daily
exposure levels for humans, including sensitive individuals.
Estimated intakes of contaminants of potential concern from
environmental media can be compared to the RfD. RfDs 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). These uncertainty
factors help ensure that the Rfd will not underestimate the
potential for adverse noncarcinogenic effects to occur.
Exposure to a contaminant was quantified by calculating the chronic
daily intake (CDI, or dose of each contaminant of potential
concern) . CDIs for potential carcinogens were calculated by
averaging exposure over a lifetime. CDls for non-carcinogens were
calculated by averaging over the period of exposure. CDIs were
estimated using concentrations of contaminants (expressed as the
reasonable maximum exposure, RME) together wi th other exposure
parameters that specifically describe the exposure pathway.
6.4
RISK CHARACTERIZATION SUMMARY
Human health risks are characterized for potential carcinogenic and
noncarcinogenic effects by combining exposure and toxicity
information. Excessive lifetime cancer risks are determined by
mul tiplying the estimated daily intake level wi th the cancer
potency factor. These risks are probabilities that are generally
expressed in scientific notation (e.g.,lO-6). An excess lifetime
-------
Parameter
ABSORPTION
Exposure Frequency (days/year)
Exposure Duration (years)
-23-
TABLE 5
MAJOR PARAMETERS FOR EXPOSURE SCENARIOS
CURRENT AND FUTURE LAND-USE CONDITIONS
Worker
Onsite
250
25
Soil Ingestion Rate (mg/day)
Soil to Skin Adherence Factor (mg/cm2)
Exposure Frequency (days/year)
Exposure Duration (years)
Soil Ingestion Rate (mg/day)
50
Worker
Onsite
260
1
480
Soil to Skin Adherence Factor (mg/cm2)
S&S CHEMICAL NPL SITE
SURFACE SOIL
INGESTION
Trespasser Worker
Onsite Onsite
100 250
30 25
100
0.2
SUBSURFACE SOIL
DERMAL
Trespasser
Onsite
100
30
0.2
DERMAL ABSORPTION
INGESTION
Trespasser
Onsite
100
30
100
:-
Worker
Onsite
260
1
0.2
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-24-
TABLE 5 (Continued)
MAJOR PARAMETERS FOR EXPOSURE SCENARIOS
CURRENT AND FUTURE LAND-USE CONDITIONS
B&B CHEMICAL NPL SITE
GROUNDWATER
Adult
Child
VOLATILES INHALATION DERMAL CONTACT
DURING SHOWERING GROUNDWATER
Adult Child Adult Child
350 350 350 350
24 6 24 6
INGESTION
Exposure Frequency (days/year)
Exposure Duration (years)
350
24
350
Ingestion Rate (liter/day)
Inhalation Rate (m3/hour)
2.0
6
0.44
0.8
0.8
Shower Duration (hour)
0.2
0.2
Skin Surface Area Available (cm2)
18,200
7,200
Source: U.S. EPA, Human Health Evaluation Manual, Supplemental Guidance: "Standard Default Exposure Factors,
Office of Solid Waste and Emergency Response, OSWER Directive 9285.6-03, Washington, DC, 1991
-------
-25-
cancer risk of 10-6 indicates that, as a plausible upper bound, an
individual has a one in a million additional (above the background
cancer incidence rate) chance of developing cancer as a result of
site-related exposure to a carcinogen over a 70-year lifetime under
the assumed specific exposure conditions at the site. Likewise, an
excess lifetime cancer risk of 10-4 indicates that an individual has
a one in ten thousand additional chance of developing cancer.
The Agency considers individual excess cancer risks in the range of
10-4 to 10-6 as protective; however, the 10-6 risk level is generally
used as the point of departure for setting cleanup levels at
Superfund sites. The point of departure risk level of 10-6
expresses EPA' s preference for remedial actions that result in
risks at the more protective end of the risk range.
Potential concern for noncarcinogenic effects of a single
contaminant in a single medium is expressed as the hazard quotient
(HQ) (or the ratio of the estimated intake derived from the
contaminant concentration in a given medium to the contaminant's
reference dose). A HQ which exceeds one (1) indicates that the
daily intake from a scenario exceeds the contaminant's reference
dose. By adding the HQs for all contaminants within a medium or
across all media to which a given population may reasonable be
exposed, the Hazard Index (HI) can be generated. The HI provides
a useful reference point for gauging the potential significance of
multiple contaminant exposures within a single medium or across
media. An HI which exceeds unity indicates that there may be a
concern for potential health effect resulting from the cumulative
exposure to multiple contaminants within a single medium or across
media.
The evaluation of risks associated with the site's surface and
subsurface soil concluded that under both current and future
exposure scenarios, noncarcinogenic risks are below 1, the level of
concern non noncarcinogens. The hazard indexes for current onsite
workers, future construction workers and future trespassers were
1. 9XlO-2, 6. 9X10-1, and 1. 4X10-2, respectively.
The evaluation of risks associated with the site's surface and
subsurface soil concluded that carcinogenic risks associated under
both current and future exposure scenarios were well below 10-4, the
level of concern for carcinogens. The cancer risks for current
onsite workers, future construction workers and future trespassers
were 2. 7X10-6, 3. 4X10-6 and 2. 7X10-6, respectively.
The evaluation of noncarcinogenic risks associated with the site's
groundwater, calculated using the most recent (January 1994) data,
concluded that risks associated with any future exposure scenarios
were below 1. Hazard indexes calculated ranged from 1.88X10-1
(MWD-07) to 6. 6X10-3 (MWF-27).
The evaluation of risks associated with the site's groundwater,
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-26-
also calculated using the most recent (January 1994) data,
concluded that the carcinogenic risk under future exposure
scenarios were below 10-6. The carcinogenic risk ranged from
7.5X10-5 (MWD-07) to 4. 9X10-7 (CDM-03).
There are uncertainties associated with any quantitative risk
assessment. Groundwater from the B&B Site contains elevated
concentrations of tentatively identified compounds, predominantly
ethylbenzenes and phenolic compounds. In January 1994, the shallow
wells in the south-central part of the site contained
concentrations of these compounds ranging from 1,230 ug/L to 1,960
ug/L. The presence of these compounds, primarily in the south-
central part of the site, contributes to uncertainties related to
the BRA, as toxicity data does not exist for the compounds. Thus,
the risk attributable to these volatile and semivolatile compounds
could not be quantified. Elimination of compounds may result in an
underestimation of risk. In addition, there are uncertainties
associated with summing cancer risks or hazard indices for
different chemicals. The assumption of dose additivity ignores
possible sYnergism or antagonism among chemicals and differences in
mechanisms of action and metabolism. It is not known what effects
this has on the total risk number.
Given the presence of contaminants concentrations greater than MCLs
and the risk levels discussed above, actual or threatened releases
of hazardous substances from this site, if not addressed by a
response action, may present an imminent and substantial
endangerment to public health, welfare or the environment.
6.5
ENVIRONMENTAL RISK SUMMARY
The B&B Site currently provides little habitat for wildlife, as
most of the site is paved or covered by warehouses. Further, the
surrounding area is primarily industrial .and residential and does
not support extensive wildlife populations. Given the limited
habitat value of the site and surrounding area, wildlife are
unlikely to use the B&B Site to any significant degree. The
intermittent exposures that could occur in the small unpaved area
of the site or in the temporary puddles (primarily urban-adapted
species) are not likely to result in any significant exposures in
wildlife populations. Therefore, no significant ecological risk
from the B&B Site is predicted to occur. The selected remedy,
which is based on protection of human health will eliminate the
potential for such toxic effects since the environmental exposure
pathways will not exist.
6.6
REMEDIATION GOALS
Because all the contaminants of concern have MCLs, the MCL values
were utilized as remedial goals for the site. The remediation
goals for the contaminants of concern are presented in Section
9.C.1.
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-27-
7.0
DESCRIPTION OF ALTERNATIVES
Five alternatives were considered for remediation of the
contaminated groundwater at the B&B Site. Institutional controls
that limit site access and usage, and semiannual groundwater
monitoring are included in all the alternatives, except the No
Action alternative.
7.1
ALTERNATIVE
1 - NO ACTION
The Superfund program requires the "No Action" al ternati ve be
considered at every site. The No Action alternative serves as a
baseline with which the other alternatives can be compared. Under
the No Action alternative, EPA would take no further action at the
site to control or minimize the migration of the contaminated
groundwater. .
Because this alternative would result in contaminants remaining
onsite, CERCLA requires that the site be reviewed every five years.
If indicated by such a review, remedial actions would be
implemented at that time to address the contaminated groundwater.
There is no cost associated with this alternative, as no additional
activities would be conducted.
7.2
ALTERNATIVE 2 - NATURAL ATTENUATION, INSTITUTIONAL CONTROLS
AND GROUNDWATER MONITORING
Alternative 2 involves the natural attenuation of groundwater
contaminants; imposition of institutional controls over the south-
central part of the property; and, groundwater monitoring to verify
that natural attenuation is occurring.
Given the currently low contaminant concentrations in the
groundwater and the observed decreasing trends in concentrations
(Appendix B), it is anticipated that natural attenuation will
further reduce groundwater contamination to below MCLs within two
years.
The existing asphalt cover located over the south-central part of
the B&B Site may be minimizing the leaching of contaminants into
the groundwater by preventing the ready infiltration of rainfall
through the vestiges of the for.mer soakage pits, as well as other
sources of groundwater contamination, documented by DERM and
subsequently by EPA. Institutional controls shall be sought to
insure that the asphalt cover is not disturbed, removed or the
integrity of the asphalt cover is not otherwise compromised in any
way. The asphalt cover will be inspected on an annual basis to
ensure that the integri ty of the asphal t cover has not been
compromised. In the event that the asphalt cover is disturbed or
otherwise compromised, EPA will be notified so that the Agency may
reevaluate the situation and the appropriate action may be taken.
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Limi tations on the use of the Biscayne aquifer currently exist
under Section 24-12(2)(Q) of the Dade County Code. These
restrictions have the effect of prohibiting the use of the Biscayne
aquifer for potable water when an approved water main is available
and operational. Under this condition, the source of potable water
is required to be from an approved public water supply main.
County approval for use of private groundwater wells installed in
the Biscayne aquifer for non-potable purposes, such as cooling,
irrigation and filling of swimming pools is generally not difficult
to obtain.
Semiannual groundwater monitoring of select groundwater monitoring
wells would be conducted to verify that natural attenuation is
occurring. Monitoring would continue until the groundwater
contaminant concentrations have decreased to levels below MCLs for
two consecutive rounds of semiannual sampling.
Groundwater monitoring of the select wells would be conducted to
verify that:
o MCLs are attained in the projected time frame;
o The spike of groundwater contaminants observed in September 1992
does not recur; and
o Further leaching of contaminants from the site's subsurface soil
does not adversely impact the groundwater
The total present worth cost of this alternative was estimated for
five years. The five year period was selected by doubling the
project two year time frame to reach MCLs and rounding. This total
present work cost was estimated to be $92,400.
7.3
ALTERNATIVE
3
GROUNDWATER EXTRACTION, PHYSICAL AND
CHEMICAL TREATMENT, AND ONSITE INJECTION
WELL DISCHARGE
This alternative involves the installation of recovery wells to
actively remediate the low-level groundwater contaminants. Aquifer
tests and additional groundwater modeling would have to be
performed during the remedial design to determine the precise
number and locations of extraction wells, as well as the necessary
pumping rates.
The groundwater treatment system would consist of an air stripping
tower for removal of volatile organic contaminants and, if
necessary, chemical precipitation for removal of heavy metals.
Should the groundwater treatment require heavy metals removal, it
is likely that a sulfide precipitation process would be need to be
used in order to achieve the remediation goals. The sludge from
the precipitation process may be hazardous because it may contain
heavy metals that could leach out. The sludge generated by the
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-29-
system would have to be initially be analyzed to determine whether
it is hazardous and to determine the proper offsite disposal
method. .
After treatment, the groundwater would be returned to the aquifer
through an injection well or infiltration gallery. Percolation
tests and limited modeling may be necessary to design the
infiltration gallery. Returning the treated groundwater to the
Biscayne aquifer would allow no net loss of groundwater.
The recovered and treated groundwater would have to be monitored to
insure compliance with State of Florida and federal MCLs prior to
reintroducing it into the aquifer.
This and all the remaining treatment alternatives would also
require long-term groundwater monitoring, in order to follow
contaminant concentration trends over time.
Assuming three recovery wells, the estimated capital cost for this
alternative is $2,440,000 and the annual operation and maintenance
(O&M) cost is estimated to be $214,600. The total present worth
cost for 10 years operation of this alternative is estimated to be
$4,097,100.
7.4
ALTERNATIVE 4 - GROUNDWATER EXTRACTION, PHYSICAL AND
CHEMICAL TREATMENT, AND OFFSITE DISCHARGE
TO SURFACE WATER
Alternative 4 is similar to Alternative 3, except that treated
groundwater would be discharged into the Miami Canal instead of
using an injection well or infiltration gallery. The Miami Canal
is about 800 feet from the B&B Chemical Site. An NPDES discharge
permit would be required and the treatment system's effluent would
be monitored to ensure it complied with the appropriate NPDES
discharge requirements. The discharged water would be required to
meet ambient water quality criteria for protection of aquatic life,
or State of Florida equivalent criteria, as opposed to MCLs.
Assuming three recovery wells, the estimated capital cost for this
alternative is $2,341,100 and the annual O&M cost is $179,600. The
total present worth cost for 10 years operation of this alternative
is approximately $3,727,900.
7.5
ALTERNATIVE 5 - GROUNDWATER EXTRACTION AND OFFSITE
DISCHARGE TO A PUBLICLY OWNED TREATMENT WORKS
(POTW)
Alternative 5 involves extraction of the contaminated groundwater
and discharging it to a local POTW. Because the contaminant
concentrations are not extremely high, it is anticipated that the
only limitations at the POTW would be due to hydraulic limitations.
Depending on the industrial pretreatment standards required by the
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-30-
POTW, this alternative allows the elimination of the physical and
chemical treatment systems.
The water that is extracted from the site would have to be
monitored to assure compliance with the POTW's industrial pre-
treatment standards and any other requirements established by DERM
and FDEP.
Assuming three recovery wells, the estimated capital cost for this
alternative is $186,300 and the annual O&M cost is $150,100. The
total present worth cost for 10 years operation of this alternative
is approximately $1,345,300.
8.0
SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
This section of the ROD provides the basis for determining which
alternative provides the best balance with respect to the statutory
balancing criteria in Section 121 of CERCLA and in Section 300.430
of the NCP. The major objective of the FS was to develop, screen,
and evaluate alternatives for remediating the B&B Chemical Site.
Several remedial technologies were identified for groundwater
restoration. These technologies were screened, based on their
feasibility with respect to the contaminants present and the site
characteristics.
The technologies that remained after the initial screening were
evaluated in detail. EPA has established nine criteria for
evaluating potential remedial alternatives. A glossary of these
evaluation criteria is provided in Table 6. These evaluation
criteria have been divided into three groups based on the function
of the criteria in remedy selection. The first two criteria on
Table 6 are threshold criteria. These two criteria relate to
statutory requirements that each alternative must satisfy in order
to be eligible for selection. The next five criteria are balancing
criteria. These are technical criteria upon which the detailed
analysis is primarily based. The final two criteria on Table 6,
known as modifying criteria, assess the public's and state agency's
acceptance of the alternative. Based on these final two criteria,
EPA may modify aspects of the specific alternative.
A summary of the relative performance of the alternatives with
respect to each of the nine criteria is provided below. A
comparison is made between each of the alternatives for achievement
of a specific criterion.
8.1
OVERALL PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
All of the alternatives, with the exception of the No Action
alternative, would provide protection of human health and the
environment by eliminating or controlling exposure to contaminated
groundwater through treatment or institutional controls. The No
Action alternative fails to restrict exposure to the contaminated
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-31-
TABLE 6
EVALUATION CRITERIA FOR REMEDIAL ALTERNATIVES
B&B CHEMICAL NPL SITE
Threshold Criteria
o
Overall Protection of Human Health and the Environment
o
Compliance with Applicable or Relevant and Appropriate
Requirements (ARARs)
Pr~ Balancing Criteria
o
Long-Ter.m Effectiveness and Per.manence
o
Reduction
Treatment
of
Toxicity,
MObility,
or
Volume
through
o
Short-Ter.m Effectiveness
o
Implementability
o
Cost
Modifying Criteria
o
State Acceptance
Community Acceptance
o
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-32-
soil and fails to monitor the progress towards natural attenuation.
Alternative 2 relies on institutional controls and monitoring for
protection until contaminant levels naturally attenuate to levels
below the MCL. Alternatives 3 through 5 rely on institutional
controls and treatment to eliminate exposure by actively
remediating the groundwater.
8.2
COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE
REOUIREMENTS ( ARARs )
Under Section 121(d) of CERCLA, the remedial action at the B&B
Chemical Site must comply with the federal and State of Florida
environmental laws that are applicable or relevant and appropriate.
Applicable requirements are those standards, criteria or
limitations promulgated under federal or state law that
specifically address a hazardous substance, pollutant, contaminant,
remedial action, location, or other circumstance at a CERCLA site.
Relevant and appropriate requirements are those that, while not
applicable, still address problems or situations sufficiently
similar to those encountered at the site and that their use is well
suited to the particular site.
Location-specific ARARs are restrictions placed on the
concentrations of hazardous substances or the conduct of activities
solely on the basis of location. Action-specific ARARs are
technology- or activity-based requirements or limitations on
actions taken with respect to hazardous wastes. These requirements
are triggered by the particular remedial acti vi ties that are
selected to accomplish a remedy. Finally, chemical-specific ARARs
are specific numerical restrictions on individually listed
contaminants present in specific media. Examples of chemical-
specific ARARs include the MCLs specified in the Safe Drinking
Water Act, as well as the ambient water quality criteria contained
in the Clean Water Act.
Although contaminants are expected to decline over time, the No
Action alternative would not provide for any measures to verify
eventual compliance with federal or State of Florida drinking water
standards. Alternative 2 would rely on passive processes to comply
with ARARs, so as to meet all MCLs in the site's groundwater and
includes measures to verify compliance while protecting the
population from exposure. Given the low contaminant concentrations
in the site's groundwater, it is anticipated that natural
attenuation will reduce these concentrations to below MCLs and
therefore protect the environment. To verify that attenuation
continues to occur, groundwater monitoring would be part of this
alternative. All of the remaining actions will be designed and
implemented so as to comply with all action- and location-specific
ARARs. Groundwater recovery and treatment, conducted under
Al ternatives 3 through 5, would have to meet chemical-specific
ARARs, through compliance with the groundwater protection standards
(i.e., MCLs) and through compliance with NPDES permit conditions
-------
1-------
-33-
for water recovered and treated at the site. Because the No
Action alternative would not comply with the two primary criteria
(Table 6), it will not be considered further in the analysis of
alternatives.
With exception of the No Action alternative, monitoring is required
in all the alternatives. This monitoring will provide the data
necessary to verify that natural attenuation of contaminants is
occurring or that treatment is effective. If it becomes apparent
that MCLs will not be met through attenuation, EPA in consultation
with FDEP, will re-evaluate the effectiveness of the remedy.
8.3
SHORT TERM EFFECTIVENESS
During the implementation of all the remaining alternatives, both
onsite workers and people surrounding the site would be protected
from possible impacts caused by construction activities, through
the implementation of a health and safety plan. Alternatives 2
through 5 will require varying amounts of time to achieve the
remediation goals. None will be immediately effective. Should a
clearly defined groundwater plume require active restoration,
Alternatives 3 through 5 would require the shortest time to be
effective because under these alternatives, groundwater would be
pumped from the aquifer for treatment, rather than relying on
passive restoration.
8.4
LONG TERM EFFECTIVENESS AND PERMANENCE
With the exception of the No Action alternative, each alternative
would be designed to meet federal of State of Florida MCLs.
Although these alternatives would be capable of providing long term
effectiveness, the alternatives do differ. Specifically,
Alternative 2 would require reassessment, based on groundwater
monitoring results and the actual effectiveness of institutional
controls. Alternatives 3 through 5 would be designed to treat and
reduce contaminant concentrations in the groundwater to the
remediation goals. Once the remediation goals are reached, the
site's groundwater would be monitored for two consecutive semi-
annual rounds to insure the effectiveness of the remedy.
8.5
REDUCTION OF MOBILITY, TOXICITY OR VOLUME THROUGH TREATMENT
With the exception of the No Action alternative, the remaining
alternatives would result in the reduction of toxicity, mobility
and volume (TMV), to varying degrees. Alternative 2 would provide
for passive, rather than active restoration of the groundwater.
The basis for the belief that passive restoration will be effective
at the B&B Site is the fact that contaminant concentrations have
declined to near MCLs as a result of an estimated two years of
groundwater pumping and treating, and that since active pumping and
treating ended, a generally declining trend in contaminant
concentrations has been observed.
The groundwater treatment contained as part of Alternatives 3
through 5' would satisfy the this criterion to a greater extent than
-------
-34-
Alternative 2, as they provide for a reduction of TMV through the
treatment of contaminated groundwater to drinking water standards.
In the case of Alternative 5, contaminants would be removed from
the aquifer, thereby reducing the mobility and volume of the plume.
Treatment by the POTW would reduce the toxicity of any contaminants
through dilution.
8.6.
IMPLEMENTABILITY
The implementability of an alternative is based on technical
feasibility, administrative feasibility and the availability of
services and materials. All of the alternatives, except
Alternative 5, are technically and administratively feasible. Due
to objections raised by the Wastewater Section of DERM, Alternative
5 is not administratively feasible.
8.7
COST
The present worth cost of each alternative given above includes the
capital cost and annual O&M costs. With the exception of
Alternative 2, which is estimated for five years, all estimated
costs assume a ten year duration. There is no cost associated with
the No Action alternative. The cost associated with Alternative 2
is exclusively those costs associated with semiannual groundwater
monitoring. The cost associated with Alternatives 3 through 5
reflect design and construction of the recovery well system;
however, Alternatives 3 and 4 also reflect costs associated with
the construction and operation of the treatment systems.
Alternative 3 includes cost associated with construction and
operation of a groundwater injection or infiltration system.
Alternative 4 includes cost associated with the construction of a
discharge outfall line and NPDES monitoring. Alternative 5
includes POTW rates for treatment.
The present worth value represents the total cost of the various
remedial alternatives expressed in today's dollars. These
estimates are based on a 5% interest rate.
8.8
COMMUNITY ACCEPTANCE
EPA solicited public comments on the remedial alternative discussed
in Section 7 of this document during the period of May 20, 1994
through June 20, 1994. The public meeting at which EPA presented
the second Proposed Plan was attended by representatives of B&B
Tritech, Inc. and one other interested party. Counsel for B&B
Tritech, Inc. provided the only written comment received during the
comment period (Appendix C). There is no indication that the
public would not support the selected remedy.
8.9
STATE ACCEPTANCE
The State of Florida, as represented by the Department of
Environmental Protection, has been the support agency during the
Remedial Investigation and Feasibility Study process for the B&B
Site. In accordance with 40 CFR 300.430, as the support agency,
-------
-35-
FDEP, has provided input during the process. Based upon comments
received from FDEP, it is expected that concurrence will be
forthcoming; however, a formal letter of concurrence has not yet
been received.
9.0
SELECTED REMEDY
Based on Comparison of the alternatives in the FS and consideration
of the requirements of CERCLA, the NCP, a detailed analysis of
alternatives, EPA has selected Alternative 2 for the site. The
selected alternative for the B&B Chemical Site is consistent with
requirements of Section 121 of CERCLA and the NCP. Based on the
information available at this time, the selected alternative
represents the best balance among the criteria used to evaluate
remedies. The selected alternative will verify that mobility,
toxicity and volume of contaminated groundwater at the site is
reduced. In addition, the selected alternative is protective of
human health and the environment, will attain all federal and State
of Florida ARABs, is cost-effective and utilizes permanent
solutions to the maximum extent practicable.
The major elements of the selected remedy which address groundwater
remediation are as follows:
o Natural attenuation of groundwater contaminants
o Source control
o Groundwater monitoring to confirm natural attenuation
9.A
Natural Attenuation
Implementation of this alternative will include the natural
attenuation of groundwater contaminants to levels below MeLs. It
is expected that natural attenuation will occur within two years,
based on the decreasing trends of groundwater contaminants
observed during the 1992 through 1994 monitoring period.
9.B . Source Control
The existing asphalt cover may be minimizing the leaching of soil
contaminants into the groundwater by preventing the ready
infiltration of rainfall through the vestiges of the former soakage
pits, as well as other sources of groundwater contamination,
documented by DERM and subsequently by EPA.
9.C
Groundwater Monitorina
Since the Dade County Code currently restricts private party use of
the BiscaYDe aquifer for potable purposes, groundwater use
restrictions would be redundant. Groundwater monitoring will be
implemented primarily to verify that natural attenuation is
occurring. Groundwater monitoring will consist of semiannual
sampling of the following monitoring wells at the site:
-------
-36-
o South-central well cluster (MWT-31, MWS-06 and MWD-07)
o Southern cluster (CDM-02, CDM-03 and MWF-27)
o Southeastern cluster (MWD-29 and MWM-29)
These wells, selected because of their historical exceedences of
MCLs, will be sampled on a semiannual basis until the groundwater
contaminants have decreased to levels below MCLs for two
consecutive rounds of sampling. The wells to be monitored may be
changed or increased in number if, groundwater monitoring shows
contaminant concentrations to have risen significantly above the
MCL. The final round of groundwater sampling will include all the
monitoring wells associated with the site. Groundwater samples
will be analyzed for the analytes on EPA's target compound,
excluding semivolatile compounds, as these compounds have not been
observed above MCLs in recent sampling rounds. The analytes on
EPA's target analyte list will be used for inorganic analytes.
9.C.1 PERFORMANCE STANDARDS
The restoration of the aquifer will be monitored semiannually until
the groundwater contaminants listed below have attained MCLs. The
listed contaminants have exceeded MCLs during the 1992-1994
monitoring period. Performance standards for these analytes are as
follows:
Vinyl chloride
Benzene
Chlorobenzene
Chromium
1 ug/L
1 ug/L
100 ug/L
100 ug/L
Performance standards are based on State of Florida MCL values.
The promulgated State of Florida MCLs for vinyl chloride and
benzene are more stringent than the federal MCLs. The major ARARs
for this remedy include but are not limited to the Federal Safe
Drinking Water Act (40 CFR Part 141) and the State of Florida
Primary Drinking water Standards, FAC 17-550, which are relevant
and appropriate.
9.C.2 COMPLIANCE TESTING
A groundwater compliance program will be developed to monitor the
progress of the groundwater restoration. Groundwater samples will
be analyzed to confirm that levels of the contaminants listed in
Section 9.C.1 continue to decline and remain below MCLs. Should
concentrations exceed MCLs or approach asymptotic levels before
achieving ARARs, EPA, in consultation with FDEP, will reevaluate
the effectiveness of the remedy and the need for further action.
Regardless, monitoring will continue until contaminant
concentrations are at or below MCLs for two consecutive semiannual
sampling rounds.
-------
-37-
10.0
STATUTORY DETERMINATIONS
The EPA has determined that this remedy will satisfy the statutory
requirements of Section 121 of CERCLA by providing protection of
human health and the environment, attaining ARARs, providing cost
effectiveness, and utilizing permanent solutions and alternative
treatment technologies or resource recovery technologies' to the
maximum extent practicable. The following sections discuss how the
selected remedy meets these statutory requirements.
10.1
PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
The selected remedy adequately protects human health by insuring
that any potential future human exposure to the site's contaminated
soil does not occur and by monitoring the contaminant levels in the
Biscayne aquifer, found in excess of federal and State of Florida
drinking water standards (MCL) during the 1992-1994 monitoring
period, continue to naturally attenuate.
10.2
ATTAINMENT OF ARARs
Remedial actions performed under CERCLA, as amended by SARA, must
comply with all ARARs or provide a justifiable waiver. The
selected remedy for the B&B Site will comply with all federal and
State of Florida ARARs and will not require a waiver.
Chemical-Specific ARARs
The performance standards for the indicator contaminants specified
in Section 9.C.1 are based on federal and State of Florida MCLs.
Federal and State of Florida MCLs are considered relevant and
appropriate when determining acceptable exposure to groundwater.
During the most recent round of sampling (January 1994), vinyl
chloride was the only contaminant detected at a concentration above
its MCL. The September 1992 through January 1994 groundwater
sampling results showed vinyl chloride, benzene, chlorobenzene and
chromium to have been present at concentrations above KCLS. If it
becomes apparent that MCLs will not be met through natural
attenuation, EPA, in consultation with FDEP, will reevaluate the
effectiveness of this remedy.
Action-Specific ARARs
ARARs for groundwater use controls include FAC Chapter 17-524, "New
Potable Water Well Permitting in Delineated Area". This State of
Florida rule restricts installation of new wells in delineated
areas of know contamination.
Location-Specific ARARs
Section 24-12(2)(Q) of the Dade County Code is an ARAR, since it
prohibits the private use of groundwater wells in areas where a
water main is available.
-------
-38-
10.3
COST-EFFECTIVENESS
After evaluating all of the alternatives which satisfy the two
threshold criteria, protection of human health and the environment
and attainment of ARARs, EPA has concluded that the selected
remedy, Alternative 2, affords the highest level of overall
effectiveness proportional to its cost. Section
300.430(f)(1)(ii)(D) of the NCP also required EPA to evaluate three
out of the five balancing criteria to determine overall
effectiveness: long-term effectiveness and permanence; reduction of
toxicity, mobility and volume through treatment, and short-term
effectiveness. Overall effectiveness is then compared to cost to
ensure that the remedy is cost-effective. The selected remedy
provides for overall effectiveness in proportion to its cost.
The selected remedy has a relatively lower present worth, as
compared to the treatment remedies, while satisfying the criteria
for long-term effectiveness and permanence, as well as short-term
effectiveness. This. alternative would not reduce toxicity,
mobility or volume through treatment; however, the reduction of
toxicity, mobility and volume through natural attenuation would be
monitored until ARARs are attained.
The estimated total present worth cost for the selected remedy is
$92,400.
10.4
UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE TREATMENT
TECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICABLE
EPA and FDEP have determined that the selected remedy provides the
best balance among the nine evaluation criteria for the five
alternatives evaluated. The selected remedy provides protection of
human health and the environment, reduces the mobility of the
plume, and is cost effective. The remedy, when complete, will be
permanent.
The NCP Preamble, 55 FR 8734, states that natural attenuation is
generally recommended only when active restoration is not
practicable, cost effective or warranted because of site-specific
conditions. The following factors were considered in determining
that groundwater contaminants should decrease through natural
attenuation: a) over 37 million gallons contaminated groundwater
treated over a 24 month period, b) low levels of contaminant
concentrations, and c) declining trends of contaminant
concentrations, once active restoration ceased. Based on the
declining trend in concentrations during the 1993-1994 monitoring
period, EPA anticipates that contaminant concentrations in
groundwater will be reduced to below performance standards within
a reasonable timeframe.
10.5
PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT
The statutory preference for treatment is not satisfied by the
selected remedy; however, natural attenuation utilizes a cost-
effective method to address any residual threat to the groundwater.
-------
-39-
Based on the limited area of the groundwater plume and the fact
that the concentrations of groundwater contaminants present,
relative to drinking water standards are low, EPA concluded that it
was impracticable to treat the groundwater effectively. The
remedial objectives of the selected remedy address the health and
environmental. threats at the site: ingestion of contaminated
groundwater.
11.0
DOCUMENTATION OF SIGNIFICANT CHANGES
EPA issued a second Proposed Plan for remediation of the site in
May 1994. The primary component of the selected remedy does not
differ from the Proposed Plan in that natural attenuation is still
the selected remedy. However, the May 1994 Proposed Plan presented
institutional controls in the form of deed restrictions. Prior to
the signature of the ROD, this component of the proposed remedy was
modified to required institutional controls in the form of a
notification agreement between EPA and the current landowner to
insure the continued integrity of the existing asphalt cover.
-------
,
APPENDIX
A
Appendix A presents graphical plots of total volatile organic
compounds for the source-area, two downgradient and the background
well clusters. The upper plot shows total target volatile organic
compound concentrations over time. The lower plot shows total
volatile organic compound concentration, including the
miscellaneous purgeable compounds, over time. Note that the scale
varies in the plots. The data plotted starts with the March 1991
remedial investigation data, followed by the September 1992,
February 1993, May 1993 and January 1994 rounds of sampling. An
exception to this is the plot for MWT-31. This well was sampled on
four additional occasions during the fall of 1993.
In addition, this appendix contains tables summarizing the
groundwater analytical data for the B&B Site. Concentrations are
in parts per billion.
-------
.c
c.
c.
.c
c.
c.
VOC TCL: B&B Chemical
MWM-26 and MWF-26
4.5
4
3.5
3
2.5
2
1.5
1
0.5
o
10
o
15 20
Months Since AI
CI MWM-26
... MWF-26
5
25
35
VOC Concentration: B&B Chemical
MWM-26 and MWF-26
4.5
4
3.5
3
2.5
2
1.5
1
0.5
~
15 20
Months Since RI
CI MWM-26
... MWF-26
10
o
5
25
35
Background Wells
-Al-
-------
.l)
Q.
Q.
240
220
200
180
16Q
140
120
100
80
60
40
20
o
500
400
300
..c
Q.
Q.
200
100
VOC TCL: B&B Chemical
MWT -31, MWS-06, MWD-07
o
10 15 20
Months Since AI Sampling
'" MWS-06 MWT -31
MWD-07
5
25
30
35
vac Concentration: B&B Chemical
MWf -31, MWS-06, MWD-07
o
10 -15 20 25
Months Since RI Sampling
a MWS-06
MWf -31 <> MWD-07
5
35
Source-area wells
-A2-
-------
VOC TCL: B&B Chemical
CDM-02. CDM-03. MWF-'ZT Cluster
~
a..
Q.
o
10 15 20
Months Since RI Sampling
CI CDM-02 + CDM-03 <>
MWF-'ZT
5
25
30
VOC Concentration: B&B Chemical
CDM-02. CDM-03, MWF-'ZT Cluster
~
a..
Q.
280
260
240
220
200
180
160
140
120
100
80
60
40
20
o
o
5
25
10 15 20
Months Since RI Sampling
CI CDM-02 + CDM-03 <>
30
MWF-'ZT
Downgradient wells
-A3-
35
35
-------
VOC TCL: B&B Chemical
MWM-29 and MWD-29 Cluster
.0
Q.
Q.
50
40
30
20
10
o
o
5
10 JS 20 25
Months SlOCe RI Sampling
CJ MWM-29
MWD-29
.0
Q.
Q.
50
40
30
20
10
o
o
VOC Concentration: B&B Chemical
MWM-29 and MWD-29 Cluster
5
10 jS 20 25
Months Since RI Sampling
CJ MWM-29
MWD-29
Downgradient wells
-A4-
30
30 ,
35
35
-------
BACKGROUND WELLS: OFFSITE
MWS-04 (7-17') MWF-26 (95-105')
Volatile Compounds Volatile Compounds
Mer-91 Sept-92 Feb-93 Mey-93 Jan-94 Mar-91 5ept-92 Feb-93 May-93 Jan-94
Vinyl Chloride U U U U U Vinyl Chloride 0_6 J U U U U
Carbon Disulfide It U U U U Carbon Disulfide U U U U U
1,2-Dlchloroethene U U U U U 1,2-Dlchloroethene U U U U U
Chloroform U U U U U Chloroform 0_8 J U U U U
cls-1,2-Dlchloroethene NA U U U U cls-1,2-Dlchloroethene NA U U U U
Benzene U U U U U Benzene U U U U U
Toluene U U U U U Toluene U U U U U
Chlorobenzene U U U U U Chlorobenzene 0_7 J U U U U
Mlsc- Volatiles U U U U U Misc. Volatiles U U U U U
Extractable Compounds Extractable Compounds
bls(2-Chloroethyl) ether U U U bI8(2-Chloroethyl) ether. U U U
bls(2-ethylhexyl)phthalate U U U bls(2-ethylhexyl)phthalate 20.0 U 12.0
1,3-Dlchlorobenzene U U U 1,3-Dlchlorobenzene U U U
1,4-Dlchlorobenzene U. ,U U 1,4-Dlchlor~zene U U U
1,2-Dlchlorobenzene U U U 1,2-Dlchlorobenzene U U U
Misc. Extractables 20.0 IN U U Misc. Extractablea 30.0 IN 20.0 IN 80.0 J
MWM-26 (25-35 ')
Volatile Compounds
Mar-91 5ept-92 Feb-93 May-93 Jan-94
I Vinyl Ch lorlde U U U U U
G; Carbon Disulfide 1.5 J U U U U
I 1,2-Dlchloroethene U 1.0 J U U U
Chloroform 1.0 J U U U U
cls-1,2-Dlchloroethene 1.5 J U U U U
Benzene U U U U U
Toluene U U U U U
Chlorobenzene U U U 0.97 J U
Misc. Volatiles U U U U U
Extractable Compounds
bls(2-Chloroethyl) ether U U U
bls(2-ethylhexyl)phthalate U U U
1,3-Dlchlorobenzene U U U
1,4-Dlchlorobenzene U U U
1,2-Dlchlorobenzene U U U
Misc. Extractables 30.0 IN U U
-------------------------------------
U: ANALYZED BUT NOT DETECTED
J: ESTIMATED VALUE
N: PRESUMPTIVE EVIDENCE OF PRESENCE OF MATERIAL
-: NOT SAMPLED OR NOT ANALYZED
WELL NAME 15 FOLLOWED BY SCREENED INTERVAL, IN FEET BELOW LAND SURFACE
-------
SHALLOW WELLS: ONSITE
M\IS-1Z (10-Z0') INS-03 (10-Z0')
Voletlle compounds Voletlle Compounds
Mlr-91 Sept-92 feb-93 Mly-93 Jen-94 Mlr-91 Sept-92 feb-93 Mly-93 Jen-94
Vinyl Chloride U U U U Vinyl chloride U U U U
Cerbon Disulfide" U U U U Cerbon Disulfide U U U U
1,Z-Dlchloroethene U U U U 1,Z-Dlchloroethene U U U U
Ch loroform U U U U Chloroform U U U U
cls-1,Z-Dlchloroethene NA U U U cls-1,Z-Dlchloroethene NA U U U
Benzene U U U U Benzene U U U U
Toluene U U U U Toluene U U U U
Chlorobenzene 1.0 J U U U Chlorobenzene 1.0 J U U 0.65 J
Misc. Voletlles U U U U Misc. Voletlles U U U U
Extrecteble Compounds Extrecteble Compounds
bis(Z-Chloroethyl) ether U U bls(Z-Chloroethyl) ether U U
bls(Z-ethylhexyl)phthellte U U bis(Z-ethylhexyl)phthelete U U
1,3-Dlchlorobenzene U U 1,3-Dichlorobenzene U U
1,4-DIchlorobenzlQl U U 1,4-Dlchlorobenzene U U
1,Z-Dlchlorobenzene U U 1,Z-Dlchlorobenzene U U
Misc. Extrectebles 90.0 J U Misc. Extrectebles U U
M\IS-11 (10-Z0') INS-05 (10-Z0')
Voletlle Compounds Voletlle Compounds
Mer-91 Sept-9Z feb-93 Mly-93 Jen-94 Mer-91 Sept-9Z feb-93 Mey-93 Jen-94
Vinyl Chloride U U U U U Vinyl Chloride U U U U U
I Cerbon Disulfide U U U U U Cerbon Disulfide U U U U U
:Po 1,Z-Dichloroethene U U U U U 1,Z-Dichloroethene U U U U U
(j\
I Chloroform U U U U U Chloroform U U U U U
cls-1,Z-Dichloroethene NA U U U U cis-1,Z-Dlchloroethene NA U U 0.87 J U
Benzene Z.O J U U U U Benzene U U U U U
Toluene U U U U U Toluene U U U U U
Chlorobenzene 85.0 10.0 U U U Chlorobenzene U 3 J U U U
Misc. Voletlles U U U U U Misc. Voletlles U U U U U
Extrecteble compounds Extrecteble Compounds
bls(Z-Chloroethyl) ether U U U bls(Z-Chloroethyl) ether U U U
bls(Z-ethylhexyl)phthelete U U U bis(Z-ethylhexyl)phthellte U U U
1,3-Dlchlorobenzene U U U 1,3-Dlchlorobenzene u U U
1,4-Dlchlorobenzene U u U 1,4-Dlchlorobenzene U U U
1,Z-Dichlorobenzene 1.0 J U U 1,Z-Dichlorobenzene U U U
Z-Methylnephthelene 4.0 J U U Misc. Extrlctlblea U U U
Misc. Extrlct.bles 230.0 IN U U
--...-......------.-.----------------...----
U: ANALYZED BUT NOT DETECTED
J: ESTIMATED VALUE
N: PRESUMPTIVE EVIDENCE OF PRESENCE OF MATERIAL
-: NOT SAMPLED OR NOT ANALYZED
WELL NAME IS FOLLOWED BY SCREENED INTERVAL, IN FEET BELOW LAND SURFACE
-------
NORTH AREA CLUSTER: ONSITE
1M-32 (4 - 1') MWD-10 (45 - 55')
Volatfle Compounds Volatfle Compounds
Mar-91 Sept-92 Feb-93 May-93 Jan-94 Msr-91 Sept-92 Feb-93 May-93 Jan-94
Vfnyl Chlorfde U U U U Vfnyl Chlorfde U U U U
Carbon Dfsulffde U U . U U Carbon Dfsulffde U U U U
1,1-Dfchloroethsn8 U U U U 1,2-Dfchloroethene U U U U
1,2-Dfchloroethene 2_D J U U U Chloroform U U U U
Chloroform U U U U cfs-1,2-Dfchloroethene U U U U
cfs-1,2-Dfchloroethene U U U 3.6 J Benzene U U U U
Benzene U U U 0.62 J Toluene U U U U
Toluene U U U U Chlorobenzene U U U 0.6 J
Chlorobenzene U U U 14.0 Mfsc. Volatfles U U U U
Total Xylenes U U U 0.63 J
Mfsc. Volatfles U U 60.0 IN U Extractable Compounds
Extractable Compounds bfs(2-Chloroethyl) ether U U
bfs(2-ethylhexyl)phthalate U U
bfs(2-Chloroethyl) ether U ,U 1,3-Dfchlorobenzene U U
bfs(2-ethylhexyl)phthalate U U 1,4-Dfchlorobenzene U U
1,3-Dfchlo~obenzene U U 1,2-Dfchlorobenzene ,U U
1,4-Dfchlorobenzene U U Mfsc. Extr8ct8bles 40.0 J U
1,2-Dfchlorobenzene U U
Mfsc. Extractables 210.0 IN 1,060 IN
MWS-09 (10 - 20')
Volatfle Compounds
> Mar-91 Sept-92 Feb-93 May-93 Jan-94
Vfnyl Chlorfde U U U U
-...J Carbon Dfsulffde U U U U
I 1,2-Dfchloroethene U U U U
Chloroform U U U U
cfs-1,2-Dfchloroethene U U U U
Benzene U U U U
Toluene U U U U
Chlorobenzene U U U 0.11 J
Mfsc. Volatfles U U U U
Extr8ctable Compounds
bfs(Z-Chloroethyl) ether U U
bfs(Z-ethylhexyl)phth8late U U
1,3-Dfchlorobenzene U U
1,4-Dfchlorobenzene U U
1,Z-Dfchlorobenzene U U
Mfsc. Extractables 90.0 J 150.0 IN
.___e_-_------------------------------
U: ANALYZED BUT NOT DETECTED
J: ESTIMATED VALUE
N: PRESUMPTIVE EVIDENCE OF PRESENCE OF MATERIAL
-: NOT SAMPLED OR NOT ANAL YlED
WELL NAME IS FOLLOWED BY SCREENED INTERVAL, IN FEET BELOW lAND SURFACE
-------
SOUTH AREA CLUSTER: ONSITE
MWT-31 (5-8')
Volatile Compounds
Mar-91 Sept-92 Feb-93 May-93 Jan-94
Vinyl Chloride U 9.0 J U U U
Carbon Disulfide U U U U U
1,1-0Ichloroethane U 6.0 J U U U
1,2-0Ichloroethene U 41.0 U U U
Chloroform U U U U U
cls-1,2-0Ichloroethene U U U U 3.6 J
Benzene U 8.0 J U U 0.62 J
Toluene U 8.0 J U U U
Chlorobenzene 8.0 140.0 30.0 U 14.0
Xylene U U 2.0 J U 0.63 J
Misc. Volatiles U U 430.0 IN U U
Extractable Compounds
bls(2-Chloroethyl) ether U U U
bls(2-ethyl~exyl)phthalate U U U
1,3-Dlchlorobenzene U U 0.62 J
1,4-0Ichlorobenzene U U 2.5 J
1,2-Dlchlorobenzene U U 6.2
2-Methylnaphthalene U 1.7J U
Naphthalene U 8.2 J U
Misc. Extractables 340.0 780.0 IN 1,960 IN
MWS-06 (10-20')
I Volatile Compounds
;J>
00 Mar-91 Sept-92 Feb-93 May-93 Jan-94
I Vinyl Chloride U 4.0 J U 1.4 J U
Carbon Olsulflde U U 13.0 14.0 U
1,1-0Ichloroethane U 3.0 J U 0.76 J U
1,2-Dlchloroethene U 17.0 U U U
Chloroform 2.0 J U U U U
cls-1,2-Dlchloroethene U U U 7.0 3.6 J
Benzene U 3.0 J U U U
Toluene U 4.0 J U U U
Chlorobenzene U 110.0 7.0 J 4.4 J 6.3
Misc. Volatiles U 3.0 IN 420.0 IN 0.77 J U
Extractable Compounds
bls(2-Chloroethyl) ether U U U
bls(2-ethylhexyl)phthalate U U U
1,3-Dlchlorobenzene U U U
1,4-Dlchlorobenzene U 1.0 J U
1,2-Dlchlorobenzene U 1.4 J U
Misc. Extractables 460.0 IN 220.0 IN 1,230 IN
_._----------------------~-----------
U: ANALYZED BUT NOT DETECTED
J: ESTIMATED VALUE
N: PRESUMPTIVE EVIDENCE OF PRESENCE OF MATERIAL
-: NOT SAMPLEO OR NOT ANALYZED
WELL NAME IS FOLLOWED BY SCREENED INTERVAL, IN FEET BELOW LAND SURFACE
IM-07 (65-75')
Volatile compounds
Mar-91 Sept-92 Feb-93 May-9] Jan-94
Vinyl Chloride U U U 2.2 J 2.1 J
Carbon Disulfide U U U U U
1,2-Dlchloroethene U 2.0 J U U U
Chloroform U U U U U
cls-1,2-Dlchloroethene U U U 0.73 J 2.0 J
Benzene U U U U U
Toluene U U U U U
Chlorobenzene 2.0 J 2.0 J U 2.0 J 4.8 J
Misc. Volatiles U U U 0.62 J U
Extractable Compounds
bls(2-Chloroethyl) ether U U U
bls(2-ethylhexyl)phthalate U U U
1,3-Dlchlorobenzene U U U
1,4-Dlchlorobe~zene U U U
1,2-Dlchlorobenzene U U U
Misc. Extractables 60.0 IN U 40.0 J
-------
SOUTH AREA CLUSTER: OFFSITE
COM-02 (10-20')
Volatile Compounds
Mar-91 Sept-92 Feb-9] May-9] Jln-94
Vinyl Chloride U U U 1.6 J U
Carbon Disulfide U. U U U U
1,1-Dlchloroethane U U 2.0 J U U
1,2-Dfchloroethene U 1.0 J 14.0 U U
Chloroform U U U U U
cfs-1,2-Dlchloroethene U U 0 4.9 J U
Benzene U/1.0 J U U U U
Toluene U U U U U
Chlorobenzene 8.0 /U 10.0 J U 4.2 J 4.4 J
Xylene U U U U U
Misc. Volatf les U U 250.0 IN U U
Extractable Compounds
bfs(2-Chloroethyl) ether 4.0 J U 1.6 J
bfs(2-ethylhexyl)phthalate U iJ U
1,3-Dfchlorobenzene U U U
1,4-Dfchlorobenzene U U U
1,2-Dfchlorobenzene U 0.79 J 0.56 J
2-Methylnaphthalene 3.0 J U U
Misc. Extractables 880.0 IN 90.0 IN 590 IN
COM-03 (40-50')
Volatfle Compounds
:1> Mar-91 Sept-92 Feb-9] May-9] Jln-94
\0 Vfnyl Chloride U/3.0 J U 14.0 0.70 J U
I Carbon Dfsulffde U U U U U
1,1-Dfchloroethane U U U U U
1,2-Dlchloroethene U U 6.0 J U U
Chloroform U U U U U
cfs-1,2-Dfchloroethene U U U 0.56 J U
Benzene U U U U U
Toluene U U U U U
Chlorobenzene U/2.0 J U U 8.0 1.7 J
Xylene U U U 0.55 J U
Misc. Volatiles U U 210.0 IN 13.52 J U
Extractable compounds
bls(2-Chloroethyl) ether U U U
bls(2-ethylhexyl)phthllate U U U
1,3-Dlchlorobenzene U U U
1,4-Dfchlorobenzene U 0.72 J 1.0 J
1,2-Dlchlorobenzene U 0.91 J 1.5 J
2-Methylnaphthalene U 2.2 J 1.8 J
Naphthalene U 8.5 J 2.4 J
Misc. Extractables U 280.0 IN 1,950 IN
----...-----.-.-----.-----.-.--------
U: ANALYZED BUT NOT DETECTED
J: ESTIMATED VALUE
N: PRESUMPTIVE EVIDENCE OF PRESENCE OF MATERIAL
-: NOT SAMPLED OR NOT ANAL YlED
WELL NAME IS FOLLOWED BY SCREENED INTERVAL, IN FEET BELOW LAND SURFACE
INF-21 (75-85')
Volatile Compounds
Mar-91 Sept-92 Feb-9] May-9] Jan-94
Vinyl Chloride 1.3 J U U 1.4 AJ 0.92 J
Carbon Disulfide 2.3 J U U U U
1,2-Dlchloroethene U 2.0 J U U U
Chloroform 4.0 J U U U U
cls-1,2-Dlchloroethene 1.8 J U U 0.73 J U
Benzene U U U U U
Toluene 1.2 J U U U U
Chlorobenzene 1.5 J 2.0 J U 3.7 AJ 2.9 J
Misc. VolatHes U U U U U
Extractable Compounds
bls(2-Chloroethyl) ether U U U
bls(2-ethylhexyl)phthalate. U U U
1,3-Dlchlorobenzene U U U
1,4-Dlchlor~zene U U U
1,2-Dlchlorobenzene U U U
2-Methylnaphthalene U U U
Misc. Extractables U U U
-------
SOUTHEASTERN AND SOUTHWESTERN CLUSTERS: OFFSITE
"""-29 (25-35') "",,-28 (25-35')
Volatile Compounds Volatile Compounds
Mar-91 Sept-92 Feb.93 May-93 Jan-94 Mar-91 Sept-92 Feb-93 May-93 Jan-94
Vinyl Chloride U U U U U Vinyl Chloride U 4.0 J U U U
Carbon Disulfide U U U U U Carbon Disulfide 2.0 J U U U U
1,Z-Dlchloroethene U U U U U 1,2-Dlchloroethene 0.8 J Z.O J U U U
Chloroform 3.0 J U U U U Chloroform 4.0 J U U U U
cls-1,Z-Olchloroethene "" U U U U cls-1,Z-Olchloroethene "" U U U U
Benzene U U U U U Benzene U U U U U
Toluene U U U U U Toluene 1.0 J U U U U
Chlorobenzene U 3.0 J U U U Chlorobenzene U Z.O J U U 0.65 J
Misc. Volatiles U U U U U Misc. Volatiles U 100.0 IN U U U
Extractable Compounds Extractable Compounds
bls(Z-Chloroethyl) ether U U U bls(Z-Chloroethyl) ether U U U
bls(Z-ethylhexyl)phthalate 18.0 U U bls(Z-ethylhexyl)phthalate U U U
1,3-olchlorobenzene U U U 1,3-0Ichlorobenzene U U U
1,4-Olchloro~nzene U U U 1,4-0Ichlorobenzene U. U U
1,2-0Ichlorobenzene U U U 1,Z-Olchlorobenzene U Z.O J U U
Misc. Extractables U U U Misc. Extractables U U 40 J
1U)-29 (40-50') M-28 (40-50')
Volatile Compounds Volatile Compounds
Mar-91 Sept-92 Feb.93 May-93 Jan-94 Mar-91 Sept-92 Feb-93 May-93 Jan-94
Vinyl Chloride U U U 1.3 J 0.54 J Vinyl Chloride 3.0 J 3.0 J U U U
I
;I> Carbon Disulfide U U U U U Carbon Olsulflde U U U U U
...... 1,Z-Dlchloroethene 0.9 J U U U U 1,2-0Ichloroethene 0.6 J 1.0 J U U U
o
, Chloroform 1.0 J U U U U Chloroform U U U U U
cls-1,Z-Dlchloroethene N" U U 0.56 J U cls-1,Z-Olchloroethene NA U U U U
Benzene U U U U U Benzene U U U U U
Toluene U U U U U Toluene U U U U U
Chlorobenzene 6.0 16.0 43.0 Z3.0 30.0 Chtorobenzene 1.0 J 1.0 J U U U
Misc. Volatiles U U U U U Misc. Volatiles U U U U U
Extractable Compounds Extractable Compounds
bls(Z-Chloroethyl) ether U U U bls(Z-Chloroethyl) ether U U U
bls(Z-ethylhexyl)phthalate 73.0 U U bls(Z-ethylhexyl)phthalate 11.0 U U
1,3-Dlchlorobenzene U 0.54 J U 1,3-Dlchtorobenzene U U U
1,4-Dlchlorobenzene U 6.5 5.4 1,4-0Ichlorobenzene U U U
1,Z-Olchlorobenzene U 3.0 J 1Z.0 9.2 1,2-0Ichlorobenzene U U U
2-Methylnephthalene U U U
Misc. Extractables 10.0 IN U 30 IN Misc. Extractables ZO.O IN U U
-------------------------------------
U: ANALYZED BUT NOT DETECTED
J: ESTIMATED VALUE
N: PRESUMPTIVE EVIDENCE OF PRESENCE OF MATERIAL
-: NOT SAMPLED OR NOT ANALYZED
WELL NAME IS FOLLOWED BY SCREENED INTERVAL, IN FEET BELOW LAND SURFACE
-------
NORTHWESTERN CLUSTER: OFFSITE
MVT-35 (4-7') M-01 (10-Z0')
Voiatlle CorrpoU1ds Voletlle Compounds
Mar-91 Sept-9Z Feb-93 Mey-93 Jen-94 Mer-91 Sept-92 Feb-93 May-93 Jen-94
Vlnyi CMorlde U U U U Vinyl Chloride U U U 0.92 J
Carbon Dlsuiflde U U U U Carbon Disulfide U U 23.0 U
1,1-Dlchloroethene U U U U 1,2-Dlchioroethene U U U U
1,Z-Dlchioroethene U U U U CMoroform U U U U
Chloroform U U U U cls-1,Z-Dlchloroethene U U U U
cls-1,2-Dlchioroethene U U U U Benzene U U U U
Benzene U U U U Toiuene U U U U
Toluene U U U U Chiorobenzene U U U 2.9 J
cMorobenzene U 2.0 J U 4.4 J Misc. Voiatltes U U U U
Xyiene U U U U
Misc. Voiatf les U U U U Extractabie Compounds
Extractabie Compounds bls(2-Chioroethyi) ether U U
bls(2-ethylhexyi)phthaiate U U
bls(Z-Chioroethyi) ether U U 1,3-Dlchiorobenzene U U
bls(Z-ethylhexyl)~thalate U U 1,4-Dlchlorobenzene U U
1,3-Dlchiorobenzene U U 1,2-Dlchlorobenzene U U
1,4-Dlchlorobenzene U U 2-Methylnaphtheiene U U
1,2-Dlchlorobenzene U 0.56 J Misc. Extractables U U
2-Methylnaphthalene U U
Misc. Extractebles 19.0 IN U
IM)-OZ (45-55')
Voletlle Compounds
:1> Mar-91 Sept-92 Feb-93 Mey-93 Jan-94
..... Vinyl Chloride U U U U
..... Carbon Disulfide U U U U
I 1,1-Dlchloroethene U U U U
1,2-Dlchloroethene 0.8 J U U U
Chloroform 4.0 J U U U
cls-1,2-Dlchloroethene U U U U
Benzene U U U U
Toluene U U U U
CMorobenzene 2.0 U U 1.7 J
Xylene U U U
Misc. Volatiles U U U U
Extractable Compounds
bls(Z-Chloroethyl) ether U U
bls(Z-ethylhexyl)phthalate U 38.0
1,3-Dlchlorobenzene U U
1,4-Dlchlorobenzene U 1.0 J
1,2-Dlchiorobenzene U 1.5 J
Z-Methyinaphthalene U U
Naphthaiene U U
Misc. Extractabies U U
-------------.-.---------------------
U: ANALYZED BUT NOT DETECTED
J: ESTIMATED VALUE
N: PRESUMPTIVE EVIDENCE OF PRESENCE OF MATERIAL
-: NOT SAMPLED OR NOT ANALYZED
WELL NAME IS FOLLOWED BY SCREENED INTERVAL, IN FEET BELOW LAND SURFACE
-------
WESTERN AND SOUTHWESTERN CLUSTERS: OFFSITE
MW1-34 (4-7') MWT-33 (4-7')
Volatile Compounds Volatile Compounds
Mar-91 Sept-92 Feb-93 May-9] Jan-94 Mar-91 Sept-9Z Feb-93 May-9] Jan-94
Vinyl Chloride U U U U Vinyl Chloride U U U U
Carbon Disulfide U U U U Carbon Disulfide U U U U
1,Z-Dlchloroethene U U U U 1,Z-Dlchloroethene U U U U
Chloroform U U U U Chloroform U U U U
cls-1,Z-Dlchloroethene NA U U U cls-1,Z-Dlchloroethene NA U U U
Benzene U U U U Benzene U U U U
Toluene U U U U Toluene U U U U
Chlorobenzene U U U U Chlorobenzene U U U 0.65 J
Misc. Volatiles U U U U Misc. Volatiles U U U U
Extractable Compounds Extractable Compounds
bls(Z-Chloroethyl) ether U U bls(Z-Chloroethyl) ether U
bls(Z-ethylhexyl)phthalate U U bls(Z-ethylhexyl)phthalate U
1,3-Dlchlorobenzene U U 1,3-Dlchlorobenzene U
1,~-Dlchlorobenzene U U 1,4-Dlphlorobenzene U
1,Z-Dlchlorobenzene U U 1,Z-Dlchlorobenzene U
Misc. Extractables U U Misc. Extractables U
MWS-15 (10-20') I4\IS-08 (10-20')
Volatile Compounds Volatile Compounds
Mar-91 Sept-9Z Feb-93 May-93 Jan-94 Mar-91 Sept-92 Feb-9] May-9] Jan-94
Vinyl Chloride U U U U Vinyl Chloride U U U U
I Carbon Disulfide U U U U Carbon Disulfide U U U U
;po 1,Z-Dlchloroethene U U U U 1,2-Dlchloroethene U U U U
f-"
N Chloroform U U U U Chloroform U U U U
I cls-1,2-Dlchloroethene NA U U U cla-1,2-Dlchloroethene NA U U U
Benzene U U U U Benzene U U U U
Toluene U U U U Toluene U U U U
Chlorobenzene U U U U Chlorobenzene U U U U
MIsc- Volatiles U U U U Misc. Volatiles U U U U
Extractable Compounds Extractable Compounds
bls(2-Chloroethyl) ether U U bls(2-Chloroethyl) ether U U
bls(Z-ethylhexyl)phthalate U U bls(2-ethylhexyl)phthalate U U
1,3-Dlchlorobenzene U U 1,3-Dlchlorobenzene U U
1,4-Dlchlorobenzene U U 1,4-Dlchlorobenzene U U
1,2-Dlchlorobenzene U U 1,2-Dlchlorobenzene U U
Z-Methylnaphthalene U U Misc. Extractables 200.0 J U
Misc. Extractables 30.0 IN U
---------------______0__0___0______-
U: ANALYZED BUT NOT DETECTED
J: ESTIMATED VALUE
N: PRESUMPTIVE EVIDENCE OF PRESENCE OF MATERIAL
-: NOT SAMPLED OR NOT ANALYZED
WELL NAME 15 FOLL~D BY SCREENED INTERVAL, IN FEET BELOW LAND SURFACE
-------
SHALLOW VELLS: ONSITE
MWS-12 (10-20') ""S-03 (10-20')
Metals Deta Metals Data
Mar-91 Sept-92 Feb-9] MaV-9] Jan-94 Mer-91 Sept-92 Feb-9] Mav-9] Jan-94
Cadnfun U U U U Cednlun U U U U
Chranlun .21.0 8.0 U U Chranfun U U U U
Lead 11.0 6.0 U U Lead U U U U
MWS-11 (10-20') MWS-05 (10-20')
Metals Data Metals Data
Mer-91 Sept-92 Feb-9] Mev-9] Jen-94 Mar-91 Sept-92 Feb-9] MaV-93 Jen-94
Cadnlun U U U U U Calun U U U U U
Chranlun U 22.0 U U U Chranlun U U U U U
Lead 6.0 11.0 U U U Lead U U U U U
BACKGROUND WELLS: OFFSITE
MWS-04 (7-17') ""F-26 (95-105')
Metals Deta Metals Data
".er-91 Sept-92 Feb-9] . Mev-9] Jan-94 . Mer-91. Sept-92 Feb-9] Mav-9] Jan-94 .
Cactnlun U 5.0 U U U Cactnfun U U U U U
Chranlun 12.0 U U U U Chranlun U U 5.0 J U U
Lead U U U U U Lead U U U U U
MWM-26 (25-35 ')
Metals Dete
I Mar-91 Sept-92 Feb-9] Mev-9] Jan-94
~ Cednlun U U U U 6.4
w Chranlun 22.0 U U U U
I
Lead U U U U 3.8
NORTH AREA CLUSTER: ONSITE
MWT-32 (4 - 1') MWD-10 (45 - 55')
Metals Data Metals Deta
Mer-91 Sept-92 Feb-9] Mav-9] Jan-94 Mer-91 Sept-92 Feb-9] MeV-9] Jan-94
Cadnlun U U U U Cactnl un U U U 10_0
Chranlun 13.0 32.0 U U Chranfun 9.0 11.0 U U
Lead 5.0 18.0 U U Lead 8.0 J 4.0 U 5_1
MWS-09 (10 - 20')
Metals Data
Mar-91 Sept-92 Feb-93 Mev-9] Jan-94
Cactnlun U U U U
Chranlun U U U U
Lead 8.0 U U U
--------------------------------------
U: ANALYZED BUT NOT DETECTED
J: ESTIMATED VALUE
N: PRESUMPTIVE EVIDENCE OF PRESENCE OF MATERIAL
-: NOT SAMPLED OR NOT ANALYZED
WELL NAME IS FOLLOWED BY SCREENED INTERVAL, IN FEET BELOW LAND SURFACE
-------
SOUTH AREA CLUSTER: ONSITE
MIIT-31 (5-8') MIID-07 (65-75')
Metals Date Metals Data
Mar-91 Sept-92 Feb-93 May-93 Jan-94 Mar-91 Sept-92 Feb-93 May-93 Jan-94 Apr-94
Caanlllll U U U U U Caani lIII U U U U 3.6
Chromlllll 21.0 16.0 U U U Chromlllll 19.0 45.0 230/190 16.0 510 U
Lead 18.0 U U U U Lead 6.0 6.0 U U 4.6
MIIS-06 (10-20')
Metals Data
Mar-91 Sept-92 Feb-93 May-93 Jan-94
Caani lIII U U U U U
Chromlllll 33.0 130.0 4.0 J U U
Lead U 7.0 U U U
SOUTH AREA CLUSTER: OFFSITE
CDM-02 (10-20') MIIF-27 (75-85')
Metals Data Metals Data
Mar-91 Sept-92 Feb-93 May-93 Jan-94 Mar-91 Sept-92 Feb-93 May-93 Jan-94
Caanillll U U U U U Caanillll U 3.0 J U U U
Chromlllll 55.0 210.0 U U U Chromlllll 13.0 U U U U
Lead 8.0 J U U U U Lead U 5.0 U U U
CDM-03 (40-50')
Metals Data
I Mar-91 Sept-92 Feb-93 May-93 Jan-94
»
~ Caani lIII U U U U U
~ Chromillll U 19.0 U U U
I
Lead U U U U 2.7
SOUTHEASTERN AND SOUTHIIESTERN CLUSTERS: OFFSITE
MWM-29 (25-35') MIIM-28 (25-35')
Metals Data Metals Data
Mar-91 Sept-92 Feb-93 May-93 Jan-94 Mar-91 Sept-92 Feb-93 May-93 Jan-94
Caanlllll U U U U U Caani lIII U U U U 5.9
Chromlllll 120.0 U U U U Chromillll 4.0 4.0 J 6.0 J U U
Lead 30.0 J U U U U Lead U U U U 3.8
MIID-29 (40-50') MIID-28 (40-50')
Metals Data Metals Data
Mar-91 Sept-92 Feb-93 May-93 Jan-94 Mar-91 Sept-92 Feb-93 May-93 Jan-94
Caanl lIII U U U U U Caanlllll U U U U U
Chromlllll 55.0 27.0 U U U Chromlllll 58.0 9.0 J U U U
Lead 4.0 J U U U U Lead 5.0 J U U U U
-------------------------------------
U: ANALYZED BUT NOT DETECTED
J: ESTIMATED VALUE
N: PRESUMPTIVE EVIDENCE OF PRESENCE OF MATERIAL
-: NOT SAMPLED OR NOT ANALYZED
IlELL NAME IS FOLLOIIED BY SCREENED INTERVAL, IN FEET BELOW LAND SURFACE
-------
NORTHVESTERN CLUSTER: OFFSITE
M\IT-35 (4-7') MWS-01 (10-20')
Metels Dete Metels Dste
Msr-91 Sept-92 Feb-93 Mey-93 Jan-94 Mer-91 Sept-92 Feb-93 Mey-93 Jen-94
Cectnt un U U U 'U Cectnfun U U U 3.6
Chromfun 11.0 U 15.0 J U Ch romt un U U U . - U
Lead ".0 J U 16.0 J U Lead U 4_0 U U
MWI)-02 (45-55')
Metels Dete
Mer-91 Sept-92 Feb-93 Mey-93 Jen-94
Cectntun 9.0 U U 3.6
Ch romt un U U 10.0 J 8.1
Lead U U U 3.1
WESTERN AND SOUTHWESTERN CLUSTERS: OFFSITE
M\IT-34 (4-7') M\IT-33 (4-7')
Metals Dete Metels Data
Mer-91 Sl!Rt-92 Feb-93 Mey-93 Jen-94 Mar-91 Sept-92 Feb-93 May:93 Jan-94
Cectnf un U U U 6.7 cectnt un 5.0 19.0 U U
Chromtun U 4.0 J U U Chromtun 12.0 4.0 U U
Lead U U U U Lead 13.0 5.0 U U
""S-15 (10-20') ""S-08 (10-20')
:1> Metals Dete Metels Data
Mer-91 Sept-92 Feb-93 Mey-93 Jen-94 Mer-91 Sept-92 Feb-93 May-93 Jen-94
~ Cectntun 6.0 U U U Cectntun U 4.0 J U U
VI
I Chromfun 48.0 19.0 7.0 U Chromtun U U U U
Leed 14.0 J 10.0 U U Lead 14.0 U U U
-___.__e_------.-------------...----
U: ANALYZED BUT NOT DETECTED
J: ESTIMATED VALUE
N: PRESUMPTIVE EVIDENCE OF PRESENCE OF MATERIAL
-: NOT SAMPLED OR NOT ANALYZED
WELL NAME IS FOLLOWED BY SCREENED INTERVAL, IN FEET BELOW LAND SURFACE
-------
APPENDIX
B
Appendix B shows linear regression curves for those analytes which
exceeded State of Florida or federal maximum contaminant levels on
at least two occasions during any of the groundwater sampling
between September 1992 and January 1994. The data plotted is that
for September 1992, February 1993, May 1993 and January 1994. When
an analyte was found below detection limits, one half of the
detection limit was used in the plot.
Two plots of the chromium data from well MWD-07 are presented. The
plot with the decreasing slope omits the January 1994 data,
discussed on page 18 of this document and includes the April 1994
data. The other plot uses the January and April 1994 chromium
data.
-------
I
txJ
~
I
Benzene: MWT-31
ppb
10
8
"
""""'''''''''''''.'''''''''.''''.''''''''''''.''''''''''''''''''''''''''''[[[""""""'."""""'"'''''''''''''''.'''''''''''''''''''''''''""'"''''''''''''''''''''''''
6
[[[""".uU'"'''''''''''''''''''''''''''''''''''''''''''''''''''',,,,,,,,,,,,,,,,,,,,,,,,"""""""""".""""""''''''[[[
4
-------
ppb
120
100
I
to
N
I
Chlorobenzene: MWS-06
.................."..........................,.............""""""""""""""""""""""""""'""",,,,,,,,,,,,,,,,,,,,""""""""""""""'"''"""""""""""""""""""""""""""'".""''''''[[[
80
"""""""""'"''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''""""""""""""""'"''''''''''''''''''''''''"""""""""'"''''''''''''''''''''''''''''''''''""""""""""""""""""""""""""""""""""""""
60
"""''''''''''''''''''''''''''''''''''''''''''''''''''''''",,,,,"""""""""''''''''''''''''''''''''''''''''''''''[[["""""''''''''''''''''''''''''''''''''''''''''''''''''''""""""""""
40
""""""''''''''''''''''''''''''''''''''''''''''''''''''''''.................
[[[""'"''''''''''''''''''''''''''''''''''''''''''''''''''''''""'"''''''''''''''''''''''''''''''''''''''''''''''''''''''''''..........................
20
"""""""""'"''''''''''''''''''''''''''''''''''''''''''"''''''''''''''''''''''''''''''''''''''''''''''''''''''''''............
-------
ppb
160
140
120
100
I
~. 80
w
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APPENDIX
c
RESPONSIVENESS SUMMARY
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.
.
Introduction
This responsiveness summary for the B&B Chemical National
Priorities List Site documents for the public record, concerns and
issues raised during the comment period for the 1994 Proposed Plan.
EPA's responses to these concerns are included below.
Overview of the Comment Period
The second Proposed Plan for the B&B Site was issued on May 19,
1994. A thirty day public comment period for this Proposed Plan
began on May 20, 1994 and ended on June 20, 1994. One written
comment letter w~s received during the comment period. A public
meeting was held on June 1, 1994 at the John F. Kennedy Library in
Hialeah, Florida. A transcript of the meeting was prepared and is
available at the site's information repository.
Concerns Raised During the Comment Period bv Counsel to B&B
Tritech. Inc.
1. The comment was made that the 1994 Proposed Plan falsely
mentioned that B&B Chemical, Inc. declined to conduct an EPA-
approved RIfFS. .
Response:
The basis for EPA' s noting in the 1994 Proposed Plan that B&B
Chemical, Inc. declined to perform an EPA-approved RIfFS is the
letter dated July 21, 1989 from counsel to B&B Chemical, Inc. In
this letter, EPA is advised that B&B Chemical, Inc. would not sign
a Consent Order for the Supplemental RIfFS at the B&B Site. This
was subsequently confirmed by EPA in a letter directed to B&B
Chemical's counsel, dated August 22, 1989.
2. The comment was made that EPA has incorrectly asserted that
there existed soakage pits at the B&B Site. Further, the commenter
observed that B&B has repeatedly requested that EPA look at aerial
photographs and other documents which purportedly confirm that no
soakage pits ever existed.
Response:
While the historical aerial photographs in EPA's files are at a
scale (300 feet to the inch) such that the soakage pits would
likely not be visible, there is ample evidence of the existence of
these soakage pits. For example, the January 1975 DERM inspector's
reports contain descriptions, sketches and photographs of the
soakage pits and other sources of groundwater contamination, as
well as analYtical data obtained as a result of the DERM
inspector's sampling of the contents of the pits. The preceding
was mentioned by EPA at a January 1991 meeting attended by EPA
representatives and their consultants, as well as consultants to
B&B Chemical, Inc.
-Cl-
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3. The commenter noted that the B&B Site should never have been
placed on the NPL to begin with and given that there was a single
exceedence of MCLs during the January 1994 sampling round, the site
should be delisted.
Response:
EPA recognizes that groundwater contaminants have declined
significantly since the start-up of pumping and treating of
contaminated groundwater; however, as observed in the body of the
ROD, the fact that contaminants are present in the subsurface soil
and spiking of groundwater contaminant concentrations has occurred,
EPA believed l~ited groundwater monitoring would insure that the
site no longer poses a threat to the environment.
4. The commenter remarked that an expenditure of an additional
$92,400, as est~ated for the selected remedy, would be absurd and
beyond belief.
Response:
As stated in the body of the ROD, the $92,400 cost for the selected
remedy is for a five year period and provides ample margin, should
MCLs not be attained in the projected two year time frame. Should
MCLs be attained within the projected two year t~e frame, the cost
would be 40% of that figure.
-C2-
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..
APPENDIX D
STATE OF FLORIDA CONCURRENCE LETTER
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