PB94-964418
EPA/ROD/R08-94/085
October 1994
EPA Superfund
Record of Decision:
Williams Pipe Line Disposal Pit
Superfund Site, Sioux Falls, SD,
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RECORD OF DECISION
WILLIAMS PIPE LINE DISPOSAL PIT SUPERFUND SITE
SIOUX FALLS. SOUTH DAKOTA
u.s. ENVIRONMENTAL PROTECTION AGENCY
REGION VIII
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DECLARATION FOR THE
RECORD OF DECISION
SITE NAME AND LOCATION
Williams Pipe Line Disposal Pit Superfund Site
Sioux Falls, South Dakota
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for the Williams Pipe
Line Disposal Pit Superfund Site (Site) in Sioux Falls, South Dakota. The remedy was.
chosen in accordance with the Comprehensive Environmental Response,
Compensation, and Liability Act of 1 980 (CERCLA), as amended by the Superfund
Amendments and Reauthorization Act of 1986 (SARA), (collectively called Superfund),
42 U.S.C. Section 9601 et seq., and, to the extent practicable, the National Oil and
Hazardous Substances Pollution Contingency Plan (NCP), 40 CFR Part 300. This.
decision is based on the administrative record for this Site.
The State of South Dakota, as represented by the Department of Environment and
Natural Resources (DENR), has worked together with EPA on cleanup studies for this
Site. The concurrence of the State of South Dakota has not been received but is
expected. A copy of the letter from the State will be included as. an attachment to
the Decision Summary.
DESCRIPTION OF THE SELECTED REMEDY
EPA has decided that No Action is necessary to address the Superfund contamination
at the Site. A minimum or two years of quarterly groundwater monitoring will be
performed to verify that unacceptable exposure will not occur in the future. This
decision applies only to the Superfund Site.
DECLARATION
EP A has determined that. no further action is. necessary at this Superfund Site to
protect humc1n health and the environment and its response at the Site is complete.
DENR is addressing groundwater petroleum contamination, which is exempt from
regulation under CERCLA. Therefore, the Site now qualifies for inclusion on the
Construction Completion List. The five-year review provision of CERCLA does not
apply to a No Action remedy.
~r;7
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DECISION SUMMARY FOR THE RECORD OF DECISION
WilLIAMS PIPE LINE DISPOSAL PIT SUPERFUND SITE
SIOUX FAllS, SOUTH DAKOTA
SEPTEMBER 1994
. .
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION VIII
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IV.
V.'
VI.
VII.
TABLE OF CONTENTS
I.
SITE NAME, LOCATION, AND DESCRIPTION. . . . . . . . . . . . . . . . . . .
1
II. -
SITE HISTORY AND ENFORCEMENT ACTIVITIES. . . . . . . . . . . . . . . .
1
III.
HIGHLIGHTS OF COMMUNITY PARTICIPATION. . . . . . . . . . . . . . . . .
3
. ,
SCOPE AND ROLE OF RESPONSE ACTION WITHIN SITE STRATEGY. " 4
SITE CHARACTERISTICS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7
1. Climate and Meteoroloav . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7
2. Surface Water Hvdrol09Y ........................... 7
3. Geologv. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8
4. Hvdrogeologv . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8
5. Land Use and Demograchv .......................... 1.0
6. Results of the Remedial Investigation. . . . . . . . . . . . . . . . . .. 10
SUMMARY OF SITE RISKS. . . . . . . . . . . . . . . .'. . . . . . . . . . . . . .. 13
Human Health Risks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1 5
Environmental Risk. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 16
DESCRIPTION OF THE NO ACTION ALTERNATIVE. . . . . . . . . . . . . .. 17
VIII. EXPLANATION OF SIGNIFICANT CHANGES. . . . . . . . . . . . . . . . . .. 17
FIGURES
TABLES
Attachment - Letter from the State of South Dakota
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DECISION SUMMARY FOR THE RECORD OF DECISION
WILLIAMS PIPE LINE DISPOSAL PIT SUPERFUND SITE
SIOUX FALLS, SOUTH DAKOTA
1...
SITE NAME, LOCATION, AND DESCRIPTION
The Williams Pipe Line Disposal Pit Superfund Site (Site) is located at the Williams
Pipe Line 12th Street Terminal (Terminal) at the intersection of 12th Street and Marion
Road (Figure 1) in northwest Sioux Falls, South Dakota. The Site consists of a
disposal pit, commonly called the "burn pond, " and contamination originating from it.
The burn pond is a small, unlined pit, about 40 feet in diameter and 7-feet deep that
is located in the northeast corner of the Terminal. With the exception of the burn
pond and tank berms, which are man-made alterations, the Site and the surrounding
. 12th Street Terminal are essentially flat, with only a very slight slope to the south
toward Skunk Creek and to the east toward the Big Sioux River (Figure 1).
The Williams Pipe Line Terminal is located in a growing urban area. Land use around
the Terminal is primarily commercial and industrial, with some residential use. The
entire 52-acre Williams Pipe Line Terminal contains 42 above ground petroleum fuel
storage tanks, a fuel loading rack, garages, an administration building, and other
support structures (Figure 2). The property is surrounded by a 6-foot chain link fence
with 24-hour access to only authorized personnel. The current zoning and anticipated
future use is industrial.
In the Sioux Falls area, groundwater in shallow unconsolidated glacial materials
. represents a significant source of water supply. Most municipal wells for the City 01
Sioux Falls. draw water from .the glacial deposits, with some wells drawing water
indirectly from the Big Sioux River. Numerous residences and businesses also derive
their water supply from wells completed in the glacial deposits.
II.
SITE HISTORY AND ENFORCEMENT ACTIVITIES
The 12th Street Terminal was constructed by the Great Lakes Pipeline Company in
the early 1940s. Before its construction, the area consisted of undeveloped,
agricultural land. The Great lakes Pipeline operated the 12th Street Terminal from
1945 until March 1966, when the Terminal was purchased by Williams Pipe Line
Company. Bulk quantities of liquid fertilizers as well as petroleum products were
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stored and conveyed at the Terminal until 1988. Currently, the Williams Pipe Line
Terminal is used to transport and store a variety of petroleum products including fuel
oil, diesel fuel, unleaded gasoline, aviation gasoline, and jet fuel. Tanks and pipe
ra~ks at the Terminal are used to convey petroleum fuel to the loading rack where
delivery vehicles are filled. The burn pond was constructed in 1945 and used until
1987 to collect storm water runoff, often contaminated with spilled petroleum, from
various areas of the Terminal. The pond also may have been used to dispose of
petroleum-related and other Terminal wastes. Petroleum products accumulating on
'the 'pond surface were periodically ignited and burned off (hence the name, burn
. .
pond). The pond no longer receives Terminal drainage, although some surface water
collects in the pond following rain or snowstorms.
The environmental investigations at the Williams Pipe Line Terminal are regulated
under both Federal and State authorities. Petroleum releases throughout the entire
Williams Pipe Line Terminal are regulated by the South Dakota Department of
Environment and Natural Resources (DENR).
Many of the early efforts, beginning in the 1980s, were investigations performed
under State authority and directed at investigating the nature and extent of
contamination from petroleum releases, such as leaks or spills, throughout the
Terminal. In November 1988, Williams Pipe Line Company signed a Settlement
Agreement with the State of South Dakota and the City of Sioux Falls for
investigation and clean up of hydrocarbon (petroleum) spills throughout the Terminal.
Releases and potential releases of hazardous substances from the burn pond area
within the Terminal are addressed by federal law (CERCLA/SARA). The U.S.
. Environmental Protection Agency (EP A) is responsible for overseeing the proper
implementation of CERCLA/SARA regulations. Petroleum products are generally
,excluded from regulation under CERCLA/SARA.
In March and November 1987, EPA conducted investigations that identified Site-
related chemicals, including some CERCLA hazardous substances, in the soil and
groundwater near the burn pond. Based on these results, the Site was placed on
EP A's National Priorities List in 1990. On January 14, 1991, EP A sent Williams Pipe
Line Company and The Williams Companies Incorporated a special notice under
CERCLA Section 122(e). This initiated the negotiation process for conducting the
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investigation of the Site. It was determined through negotiations that Williams Pipe
Line Company was the owner of the property and independent of Williams Companies
Incorporated.
. .
In 1991, Williams Pipe Line signed a legal agreement, titled an Administrative Order
on Consent, to conduct a CERCLA remedial investigation (RI) and (focussed) feasibility
study (FS). The purpose of the remedial investigation, which was conducted in two
phases from 1991. to 1993, was to more fully investigate the. nature and extent of
hazardous substance 'contamination'in the burn pond area. Possible contaminants of
concern identified in the burn pond area soils and/or groundwater included volatile
organic compounds (VOCs), semivolatil~ organic compounds (SVOCs), metals,
pesticides, and polychlorinated biphenyls (PCBs).
In 1994, Williams Pipe Line completed an evaluation (the focussed FS) of several
management practices for addressing the Superfund contamination. The focussed FS
provides more detail about the costs of monitoring and describes the current
stipulations for groundwater access on and near the Williams Pipe Line Terminal.
III.
HIGHLIGHTS OF COMMUNITY PARTICIPATION
EPA conducted interviews with local officials and residents during March 1991 to
assess community concerns about the Williams Pipe Line Site. A community relations
plan outlining a program to address community concerns and keep citizens informed
about and involved in remedial activities was distributed in June 1992. Also in June
1992, EPA issued a fact sheet updating the community regarding ongoing
. .
investigations at the Site.' The same month, EPA established an administrative record
that was available for public review at the Sioux Falls Public Library in Sioux Falls,
South Dakota; the State 01 South Dakota Library in Pierre, South Dakota; and theEPA
Superfund Records Center in Denver, Colorado. EPA also established a repository for
Site information at the Sioux Falls Public Library. pursuant to CERCLA Section 113.
In June 1994, EPA issued a fact sheet briefly summarizing the results of previous
investigations, the results of the Baseline Risk Assessment, and upcoming
opportunities for community involvement. .
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EP As Proposed Plan for remedial action at the Site was issued in fact-sheet format
in July 1994. The Proposed Plan fact sheet summarized the Site history and
background, the results of the Remedial Investigation, the results of the Baseline Risk
Assessment, the 'description of the preferred remedial alternative, and information
about the public meeting and comment period. On July 24, 1994, an announcement
was published in the Argus Leader newspaper to inform the community that a public
meeting would be held by EP A. In early August, Williams Pipe line Company issued
a press release that also provided information, about the public meeting.
From July 25 to August 24, 1994, EP A offered a 3D-day public comment period to
accept public comment on the Proposed Plan and Remedial Investigation, or receive
new information. EPA held a public meeting at Hayward School Gymnasium in Sioux
Falls on August 16, 1994, to discuss the results of the Remedial Investigation,
present the Proposed Plan', and accept oral comments. A transcript of the meeting
is available in the administrative record. Comments from the meeting attendees, and
EP As response to these comments are included in the Responsiveness Summary. No
written comments were received during the public comment period.
IV.
SCOPE AND ROLE OF RESPONSE ACTION WITHIN SITE STRATEGY
The selected alternative for the Williams Pipe line Superfund Disposal Pit Site is "No
Action with Groundwater Monitoring." No construction activities are associated
with the "No Action" alternative. Two years of groundwater monitoring near the Site
will be undertaken to confirm that no unacceptable exposures due to arsenic migrating
offsite may occur in the future.
This "No Action" alternative pertains only to the Superfund work. It is not a
determination that no action is warranted under other regulations and statutes,
including State authorities. In choosing this alternative, EPA assumes that the work
to clean up petroleum-contaminated groundwater at the Terminal will continue under
State authority.
EPA believes the "No Action with Groundwater Monitoring" alternative sufficiently
addresses Superfund health risk concerns for two major reasons. First, exposure to
contaminants for which the potential risks exceed the acceptable levels is highly
unlikely. Second, much of the estimated risk is attributed to petroleum constituents,
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and the petroleum groundwater contamination is being addressed by DENR under
South Dakota's Chapter 34A-2, Water Pollution Control Laws. Health risk for
petroleum should be adequately addressed under the State authority.
As noted in the "Summary of Site Risk" section, a potential risk might exist if
someone were to drink the unfiltered groundwater that contained high levels of
arsenic. Arsenic analysis of unfiltered water samples is referred to as total arsenic.
Risk evaluations generally consider the .Federal drinking water standard, which utilize
unfiltered groundwater analysis. The assumption is that unfiltered groundwater
samples will contain small particles that could flow with the groundwater but not
larger sediment particles. However, this was not the situation for the samples
collected during the RI.
The groundwater data collected during the. RI indicate that the filtered water, which
would contain dissolved arsenic, more closely represents the potential concentrations
that may be found in drinking water near the Site. The sampling data showed that
large amounts of sediments from subsurface materials surrounding the monitoring
wells were collected with the groundwater samples, probably due to the sampling
method. The unfiltered water analyses performed on these samples included
sedimentary particles in addition to the small particles that might flow with
groundwater. At the high sediment content found in the samples, groundwater
would not be drinkable. The filtered water analysis filters out large particles, including
the sedimentary particles containing arsenic, but includes arsenic dissolved in the
water. Dissolved arsenic was not only below the drinking water standard, it was not
. found in any of the offsite filtered groundwater samples. Thus, there is no potential
exposure or risk from dissolved ars~nic when drinking this groundwater. Nor is there
any feasible likelihood of future exposure or risk due to the operation of the existing
groundwater recovery system that is explained below. Groundwater monitoring is
proposed as part of the "No Action" alternative to confirm that arsenic at
unacceptable levels is not present in groundwater that might be used for drinking.
Additionally, DENR is continuing oversight of Williams Pipe Line's cleanup of
petroleum contamination in the groundwater at the Terminal. The health risks from
petroleum (mostly benzene) contamination in the groundwater at the Site will be
addressed through State DENR authorities. A groundwater recovery and treatment
system, including components near the burn pond, is being operated under the State
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Settlement Agreement. Data collected under the RI and State investigation indicate
that the groundwater recovery system is preventing the contamination, including
arsenic contamination, from moving further offsite.. The proposed. groundwater
monitoring is expected to confirm this finding.
Groundwater recovery system components near the burn pond include one recovery
well (RW-5), interception trenches 1 and 2, and the eastside treatment building. The
system captures tne groundwater that might .otherwise move under the Terminal
boundaries. The groundwater is treated prior to being discharged to the city sanitary
sewer system. Discharge requirements are controlled through a permit by the City of
Sioux Falls. Williams Pipe Line has also applied for a direct discharge permit with the
State. If approved, it will allow discharge of the treated water directly into Skunk
Creek under the specific requirements, which include contaminant concentration
limits. Thus, it does not appear that further work to clean up the CERCLA hazardous
substances would provide additional benefits.
South Dakota State regulations, (reference Chapter 74:03:30, Above Ground Storage
Tanks), require that before the Terminal is permanently closed, soil and groundwater
contamination must be cleaned up. Therefore, before the property could be used for
residences, the contamination that might present a risk to residents would need to be
addressed. Additionally, the current industrial zoning would need to be changed.
The proposal in no way limits the State's authority under its laws. In fact, EPA's
decision is partly based on the fact the cleanup of the petroleum contamination under
State authorities will continue and access to the Site and groundwater underneath the
Terminal will continue to be controlled.
EPA has authority to revisit a "No Action" remedy. This could occur if future
conditions indicate that an unacceptable risk to human health or the environment
would result from exposure to hazardous substances at the Site. Additionally, if the
groundwater monitoring leads to a different conclusion than presented here, EPA
would review its decision.
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v.
SITE CHARACTERISTICS
1.
Climate and Meteorologv
Minnehaha County, South Dakota lies in a climatic section of the United States termed
the Humid Continental Warm Summer Climate, characterized by wide annual ranges
in temperature, hot wet summers, and cold dry winters. . The average annual
precipitation for Sioux Falls is 24.12 inches, with spring and summer being the.
seasons of maximum rainfall. Average annual snowfall is 32 inche~. The average
daily temperature is 45.3 degrees Fahrenheit (OF). The coldest month is January,
with an average daily temperature of 12.4 of, and the warmest month is July, with
an average daily temperature of 74.0 of. The average wind speed and direction is 11
mph from the south/southeast in the summer, and 12 mph from the north and
northwest during the fall and winter.
2.
Surface Water Hvdroloav
The principal surface water features in the area are the Big Sioux River and its
tributary, Skunk Creek. The Site is located about two miles northwest of the
confluence of the two streams. Two rock quarries located about 1.25 miles northeast
of the Site expose the groundwater table as surface water. Small intermittent
drainages also discharge surface runoff to storm sewers, the Big Sioux River, and
Skunk Creek.
Surface water runoff at the Site is a direct result of precipitation. Surface water in
the vicinity of the bu.rnpo.nd drains to the southeast by way of a small drainage ditch
located less than 100 feet southwest of the burn pond. The ultimate fate of storm
water runoff from both offsite (outside the Terminal boundaries) and onsite (within the
Terminal boundaries) sources near the burn pond is discharge to the City storm water
drain along Marion Road. Some precipitation and storm water runoff may accumulate
in the burn pond.
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3.
Geologv
Regional surficial geology is characterized by deposits of glacial and glacial-fluvial
origin. These outwash deposits, composed of silt, sand, and gravel, are generally 20-
to-35 feet thick. Thicker deposits (55-to-80 feet thick) of coarse sand and gravel
occur beneath the flood plain of Skunk Creek. Basal till deposits of clay and sandy,
silty clay, 6- to 48-feet thick, underlie the thicker outwash (sand and gravel) deposits.
The basal till deposits become thinner .to nonexistent in the alluvial valley of Skunk
Creek. The Precambrian Sioux Quartzite bedrock occurs in the immediate area of the
burn pond at depths of 38 to 70 feet below land surface in the area.
At the Site, the glacial deposits are divided into two units. Unit 1 (Figure 3) is
composed of poorly sorted outwash deposits, and is further subdivided into two
subunits based on differing grain size and hydrogeologic properties. Unit 1 A consists
of more permeable sand and gravel deposits; Unit 1 B consists of less permeable silts
and clays. The outwash deposits are poorly sorted and Units 1 A and 1 B often are
interbedded, transect each other, and exhibit a cut and fill relationship. Unit 2, which
underlies Unit 1, is a basal till deposit of unsorted sands, gravels, and boulders in a
clay and silt matrix. The basal till is 9 to 18 feet thick in the immediate vicinity of the
burn pond. The glacial deposits are underlain by Unit 3, Sioux Quartzite and remnant
Cretaceous bedrock. The bedrock is approximately 50-feet deep in the immediate
vicinity of the burn pond. The Site geology is illustrated in Figure 3, which is an east-
'west geologic cross-section passing through the burn pond Site.
4.
Hvdroaeoloav
In the Sioux Falls area, the glacial outwash deposits represent a significant source of
water supply. The City of Sioux Falls obtains much of its drinking water supply from
municipal wells drawing groundwater from the outwash and indirectly from the Big
Sioux River. In addition, numerous Sioux Falls businesses and residences derive their
water supply from wells drawing water from the outwash deposits.
Groundwater is recharged from precipitation that infiltrates vertically into the ground.
Groundwater within the outwash deposits moves horizontally toward surface-water
bodies located at topographically lower elevations. Regional groundwater flow
directions are east toward. the Big Sioux River and south toward Skunk Creek.
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Groundwater flow within the outwash deposits in the burn pond area is to a large
degree influenced by the existing groundwater recovery systems (RW-5 and
interception trenches 1 and 2). Groundwater flow in the eastern half of the Terminal
area is from the center of the Terminal toward the northeast, east, and southeast.
Groundwater flow in the immediate vicinity of the burn pond is toward the northeast.
Groundwater levels and flow directions in the outwash deposits are illustrated in
Figure 4, which shows groundwater conditions in October 1993. Groundwater flow
in the basal till (Unit 2) east of the burn pond is toward the southeast. The average
groundwater flow velocity in the outwash deposit~ (Unit 1 A), before the operation of
recovery well RW-5 and interception trenches 1 and 2, was approximately 320 feet
per year and generally. to the southeast across the Site. The groundwater flow
velocity in the basal till is estimated to be 0.2 foot per year.
Operations of interception trenches 1 and 2 and RW-5 have lowered groundwater
levels along the eastern side of the Terminal by as much as 15.5 feet. As a result of
pumping, grou.ndwa~er flow northeast of the Site has been reversed and groundwater
gradients downgradient of the recovery systems have become less steep. The
effective groundwater capture area of RW-5 includes groundwater beneath the burn
. pond. As a result of regional groundwater flow gradients, the effective capture area
of RW-5 extends no more than 150 feet downgradient of the recovery well. The
effective capture area of the trenches includes areas of the Site south of the burn
pond. As a result of regional groundwater flow gradients, the effective downgradient
capture area of the trench system is approximately 5 to 10 feet.
RW-5 and the northern end of trench 1 have overlapping zones of influence.
Individual sumps along trenches 1 and 2 also overlap. Stagnation points or
. .
groundwater divides occur between individual pumping centers. Weak hydraulic
gradients occur across sections of the trenches and between the north end of trench
1 and RW-5.
RW-5, trench 2, and most of trench 1 fully penetrate the coarse-grained materials of
Unit 1 A. Only the north end of trench 1 does not fully penetrate the Unit 1 A
materials. local water-level gradients indicate that groundwater flow in Unit 1 A
below the north end of the trench is influenced by recovery system operations,
although the possibility of slight underflow of groundwater beneath the north end of
trench 1 exists.
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5.
Land Use and DemoaraDhv
The Terminal is currently zoned industrial. The area surround!ng the Site is zoned
industrial and commercial. There are houses northeast of the Site along Marion Road
and north of 9th street. Residential areas also exist south of the 12th Street
commercial strip. A draft City Planning and Building Services land use map for the
year 2015 shc;>ws the Terminal as industrial with the surrounding area remaining light
industrial and commercial.
A number of private wells exist in the area surrounding the Site but most of these are
not in use or abandoned. Most of the wells near the Site that are designated in use
are on commercial property. The City of Sioux Falls draws most of its water from
wells located 3 miles northeast of the Site. An additional city well is located about
1.5 miles southeast of the Site along Skunk Creek.
Human receptors who might be potentially exposed to Site contaminants include
onsite workers, and area residents and workers. n Area", in this context, refers to
residential and industrial properties located adjacent to the 12th Street Terminal.
Future populations that could potentially be exposed to Site contaminants include
onsite residents (if the site were to be developed for residential use) and children
trespassing on the property. The environmental assessment concluded that no real
threat to area wildlife exists due to very limited exposure of wildlife to hazardous
substances.
6.
Results of the Remedial Investigation
RI Phase I. The nature and extent 01 contamination in and around the burn pond was
evaluated during the Phase I RI. The analytical results confirm that the burn pond was
a source of past releases of contamination to the environment.
Soils within the burn pond contained elevated levels of volatile organic compounds
(VOCs), semivolatile organic compounds (SVOCs), and total petroleum hydrocarbons
(TPH), which are common constituents of petroleum products or combustion by-
products. Except for benzene, surface soils did not contain VOCs. Surface soils did
contain elevated SVOCs associated with petroleum, primarily within 10 feet of the
edge of the burn pond. VOCs and SVOCs are generally found in the subsurface soils
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within 30 feet of the burn pond, and extend to depths of approximately 25 feet below
ground surface, the approximate depth of the water table at the time of sampling.
Low concentrations of pesticides (insecticides) and PCBs were detected in shallow
soils. Pesticides were not detected at depths greater than 5 feet, and PCBs were not
detected at depths greater. than 15 feet. Herbicides were detected in both Site soils
and background soils. Several metals were detected in soils within and adjacent to
the burn pond at concentrations potentially in slight excess of background ranges.
Table 1 provides a summary of concentrations of Site .contaminants detected in
surface soils during the Phase I RI. Table 2 provides a similar summary for subsurface.
soils.
Spills or leaks of petroleum products are known to have occurred at several places
within the Terminal. Free-phase petroleum product has been detected on the water
table in the vicinity of the burn pond in thicknesses of less than one foot. The
thickness and areal extent of free product has gradually decreased since 1987,
primarily due to operation of recovery well RW-5. At the completion of the Phase I
RI, measurable 1ree product was no longer present beneath the burn pond, although
free product was still being recovered at RW-5.
VOCs and SVOCs with petroleum hydrocarbons have been detected in groundwater
at the Site. With the exception 01 benzene in monitoring wells northeast 01 RW-5 and
1,2-dichloroethane (1,2-DCA) in a monitoring well east of trench 1, Site-related
. organic compounds were not detected at of1site monitoring points beyond the control
01 the active recovery systems. PestiCides have not been detected in groundwater
since 1988, shortly after groundwater recovery operations began in the vicinity of the
burn pond. The active recovery systems appear to have reduced the extent of
petroleum hydrocarbons and indirectly reduced pesticide concentrations in the
groundwater.
Inorganic compounds and metals have been detected in groundwater beneath or near
the burn pond at concentrations in excess 01 drinking water standards. Arsenic was
the only metal detected in filtered groundwater samples in excess of drinking water
standards. Nitrate concentrations were elevated in groundwater north 01 the burn
pond, and the distribution 01 elevated nitrates suggests a possible of1site source.
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Elevated nitrate concentrations have also been detected along the southern Terminal
property boundary where nitrate fertilizer was once contained in Terminal storage
tanks. Nitrates are being addressed under the State clean up since not associated
with the Superfund Site.
RI Phase II. The existing recovery systems have been successful in removing
contaminants from the groundwater. As of 1992, RW-5 had recovered approximately
15,000 gallons of. free-phase petroleum; seven pounds of dissolved petroleum
constituents; 4,100 pounds of nitrate; and 7,000 pounds of ammonia. The recovery
trenches have recovered approximately 18,000 gallons of free-phase petroleum; 65
pounds of dissolved petroleum constituents; 1,400 pounds of nitrate; and 6,500
pounds of ammonia.
Groundwater in the vicinity of the burn pond area still contains VOCs and SVOCs
associated with petroleum hydrocarbons. The distribution of dissolved compounds
detected during Phase II investigations was consistent with the distribution detected
in previous years, although the areal extent of benzene northeast of RW-5 and 1,2-
DCA east of trench 1 appears to have been reduced between 1992 and 1993. Table
. 3 provides a summary of chemical concentrations for compounds detected in
groundwater samples collected during the Phase I RI, Phase II RI, and previous
investigations.
Total (unfiltered) arsenic concentrations detected by Phase I and Phase II sampling
(Table 4) are believed to be primarily due to the presence of arsenic complexes on
particulates in unfiltered groundwater samples. Dissolved concentrations of arsenic
were, however, detected in Phase II samples collected from nine monitoring wells
(Table 5). Dissolved (filtered) arsenic was detected in monitoring wells onsite but was
not detected in any offsite monitoring wells. Three of the onsite wells contained
dissolved arsenic concentrations in excess of the drinking water standard (50
micrograms per liter). The locations of wells listed in the tables are shown in Figures
4 and 5. .
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The source of the arsenic contamination is unclear since it is unknown what
. contaminants may have been discharged to the burn pond. Much of the arsenic can
be attributed to background or naturally occurring levels. Wells sampled as
background wells during Phase II did not contain dissolved (filtered) arsenic but
several showed elevated levels of total (unfiltered) arsenic.
Groundwater samples collected at the interception trenches and RW-5 contained Site-
related organic compounds and arsenic. CQupled with the fact that water quality
samples from wells downgradient of the recovery systems did not contain Site-related
chemicals, this supports the conclusion that RW-5 and trench 1 are effective in
containing and recovering chemicals of concern from the groundwater.
VI. SUMMARY OF SITE RISKS
A Base Line Risk Assessment (BRA) was performed to estimate the probability and
magnitude of potential adverse human health and environmental effects from exposure
to hazardous substances associated with the Site. The public health risk assessment
followed a four step process:
1) contaminant identification, which identified those hazardous substances
of potential health concern;
exposure assessment, which identified actual or potential exposure
pathways (routes where people contact the chemicals) , characterized the
potentially exposed populations, and determined the extent of possible
exposure;
toxicity assessment, which considered the types and magnitude 01
adverse health effects associated with varying amounts of the hazardous
substances of concern; and
risk characterization, which integrated the three
summarize the actual current and future potential
exposure to hazardous substances at the Site.
2)
3)
4)
previous steps to
and risk posed by
EPA prepared the BRA in October 1993. An addendum to the Baseline Risk
Assessment was prepared in May 1994. The addendum included analytical results'
from additional groundwater samples collected during the Phase II RI work. The
Baseline Risk Assessment used the Site data and the process explained above to
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estimate potential cancer and non-cancer risks to humans from exposure to hazardous
substances at the Site in the absence of any cleanup work. .
Contaminants of concern identified in the BRA and BRA Addendum are listed in Table
6. The BRA evaluated potential exposure pathways by which people may come in
contact with hazardous substances from the Site. For each pathway evaluated, an
average and reasonable maximum exposure (RME) estimate was calculated. The RME
represents the maximum exposure that could reasonably be expected to occur for a
. given exposure pathway at the Site. . . .
Major pathways evaluated in the Baseline Risk Assessment include: 1) both onsite .
and o11site groundwater used as drinking water; 2) inhalation of windblown dust; and
3) incidental soil ingestion. Groundwater is the primary contaminant pathway for
possible exposure from the Site hazardous substances.
Current and future populations that potentially could be exposed to contaminants that
were evaluated in the Baseline Risk Assessment included: 1) onsite workers; 2) area
residents; and 3) area workers. n Area" refers to residents and workers on nearby
properties. Additional future populations that potentially could be exposed to
contamination evaluated in the Baseline Risk Assessment include onsite residents and
children trespassing on the property.
Under Superfund regulations, cancer and non-cancer risks are considered at Superfund
sites. For cancer, resulting risk estimates are expressed in scientific notations as a
probability (e.g. 1 x 10-6 for 1/1,000,000). The risk indicates an individual's lifetime
chance of developing cancer as a res.ultof exposure to Site related contaminants over
30 years, 350 days a year. EPA generally considers estimated cancer risks from Site
contamination that fall below the range of one additional chance in ten thousand to
one additional chance in a million (1 x 10-4 to 1 X 10-6) of developing cancer as
acceptable. This risk is in addition to the normal (larger) overall cancer rate for the
general population. The range is used to allow for management and site-specific
considerations that are still protective of public health. Current EPA practice considers
cancer risk to be additive when assessing exposure to a mixture of hazardous
substances.
-------
For non-cancer risk, a -comparison of acceptable background and/or safe levels of
chemicals to Site contamination is made. This comparison is called a hazard quotient.
If the hazard quotient is less than or equal to one, it is considered ~cceptable for
health protection. A hazard quotient of one or less represents a level of exposure that
would not harm the most sensitive person over a 30-year period .of exposure. The
hazard quotient associated with ea.ch contaminant is added for each pathway.
Both the cancer and non-cancer risk estimates are generally conservative. This means
that any uncertainty. in the risk estimates is offset by the protective safety factors
used in the Baseline Risk Assessment. Toxicity and exposure values are used to
calculate the risk to protect sensitive individuals under the maximum exposure
possible (RME). This provides for suitable public health protectiveness for all people.
. .
Human Health Risks
Based on the BRA, Site carcinogenic and noncarcinogenic risks are below or within
EPA's acceptable cancer risk range and the acceptable hazard quotient, except for
two scenarios explained below. Tables 7 and 8 summarize those chemical-specific
and total pathway carcinogenic (cancer) risks that exceed one additional chance in ten
thousand of developing cancer, and the noncarcinogenic hazard quotients that exceed
one. Exposure to contaminants of concern through other path~ays did not present
unacceptable risks.
The two exceptions noted above are a hypothetical resident living onsite, and an area
resident drinking unfiltered groundwater that includes total arsenic. The potential
. .
onsite resident risk is due to drinking groundwater or a child incidently eating small
amounts of burn pond soils. As explained in the following paragraphs, there is no
apparent current or likely future exposure under these scenarios. Since no completed
exposure pathways exist, there is no health risk.
The onsite resident scenario conservatively assumes someone is living onsite and
drinking the groundwater at current contamination levels for a period of 30 years, or
is a child who incidentally eats burn pond soil. The potential cancer risk for the
resident is based primarily on exposure to benzene and arsenic (total or dissolved) in
the groundwater. Benzene is a hazardous substance and a common constituent of
petroleum. At high levels and/or long":term exposure benzene can cause leukemia, a
-------
type of cancer. Exposure to high levels of arsenic may lead to skin disorders or skin
cancer. The risk to a child living onsite who might eat soils is caused maii-lly by
benzo(a)pyrene, a SVOC associated with petroleum.
Currently, no residents live onsite, the Terminal is fenced, and access is restricted; so
there is no exposure to groundwater contaminated with arsenic and, thus, no risk.
The contaminated groundwater is prevented from moving offsite by the groundwater
recovery system which is operated under dir.ection of DENR. The system is being
operated to capture and treat the groundwater contaminated with petroleum
constituents, including benzene and benzo(a)pyrene. The groundwater that includes
the high levels of arsenic is also being captured by this system, thus preventing the
contamination from moving to the area east of the Terminal. As the petroleum
groundwater contamination is cleaned up as required by the State, the arsenic
groundwater contamination will also be cleaned up. The State may also address the
petroleum contamination in the burn pond soil under its Settlement Agreement with
Williams Pipe Line.
Under the second exception, some risk to area residents would exist under the current
land-use scenario if people were drinking unfiltered groundwater contaminated with
(total) arsenic. However, groundwater sampling data showed that no exposure should
occur. Private drinking wells are generally constructed to remove sediment from
groundwater. The RI groundwater samples that contained high total arsenic levels also
contained high amounts of sediments and would be unfit to drink. Dissolved arsenic
levels, that potentially would be found in filtered groundwater samples, were
determined to more closely represent what might be found in drinking water. No
. dissolved arsenic was found in the offsite groundwater, so. no exposure to this
contaminant exists for area residents potentially drinking the groundwater.
Additionally, most area residents are connected to the city water supply system.
Environmental Risk
The environmental assessment determined that. no real threat to area wildlife exists
due to very limited exposure of wildlife to hazardous substances. Additionally, there
is a very small likelihood that any Site impacts should have any significant population-
wide effects.
-------
VII.
DESCRIPTION OF TIiE NO ACTION ALTERNATIVE
EP A has determined based on the results of the RI, BRA, and considering Site specific
conditions, that No Action is needed for remediation of the groundwater at the
Williams Pipe Line Disposal Pit Superfund Site. There are no construction activities
associated with the No Action decision. However, monitoring will be performed to
verify the conclusions that are based on the RI data.
At a minimum, two 'years of monitoring on a quarterly basis will be performed to
confirm that no unacceptable exposures will likely occur in the future. The
groundwater monitoring should confirm that no unacceptable levels of arsenic are
migrating from underneath the Williams Pipe Line Terminal to areas near the Terminal.
A number of existing monitoring wells are located on and near the Site (see Figure 5).
A subset of the wells on or near the Site will be selected as the groundwater
monitoring points. The cost of the monitoring for two years is estimated at $35,000.
This determination applies only to the Superfund Site and associated contamination.
It is not a determination that no action is warranted under other regulations and
statutes, including State authorities. Petroleum related contaminants (including
benzene) are being investigated and cleaned up under State authorities.
VIII.
EXPLANATION OF SIGNIFICANT CHANGES
EPA distributed a Proposed Plan (preferred alternative) for remediation of the Site in
. July 1994. The Proposed Plan described EPA's decision to, pursue no further action
with one to two' years of groundw.ater monitoring at the Williams Pipe Line Disposal
Pit Superfund Site. No significant changes have been made to the No Action with
Groundwater Monitoring decision described in the Proposed Plan. However, the
Selected Remedy specifies that at a minimum, two years of quarterly groundwater
monitoring is required.
-------
-------
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CLAY INTERPRETED AS TILL
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UNITS
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UNIT I-OUTWASH DEPOSITS
A OUTWASH SANDS & GRAVELS
(COLORED BLUE)
B OUTWASH CLAYS & SILTS
GRAVEL UNIT 2- TILL
OUARTZITE UNIT 3-SIOUX QUARTZITE BEDROCK
ALL UNIT THICKNESS LESS THAN 6-INCHES ARE NOT SHOWN
THE FLUID LEVELS SHOWN FOR PIEZOMETER LOCATIONS ARE MEASURED
IN THE UPPER (U) PIEZOMETER OF EACH CLUSTER.
THE MONITOR WELLS SAMPLED DURING PHASE I RI ARE COLORED PINK.
WilLIAMS PIPE LINE COMPANY
. 12TH STREET TERMINAL, BURN POND SITE
SIOUX FALLS. SOUTH DAKOTA
GEOLOGIC CROSS-SECTION T - T'
REVISED
--- JRC
JRC
JRC
Pnpared By:
LEGGETTE, 8RASHEARS & GRAHAII, INC.
ProlesslaDaI CrouDd-W.".r CaDII.1Jlanl8
..Xg~~~~t Il::~fe~::~ sBuiP;U~84
Slou% FaUs. SO ~7108
(605) 361-6000
DATE: MARCH 1993 ~~!. 3
f'ILE:
6y/PBPET2.0WG
Source: Williams PIpe Line 12th Streel TermInal. Burn Pond 5118. Sioux Fells. South DakOl8 Sile Char8Clerl18l1on Summery, Vol. 11
Figure 3:
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-------
-------
TABLE 1
(page 1013)
WILLIAMS PPE LINE COWANY 12TH STTERMINAl
B~N paN> SLPERFUN> SITE
Summary of Concentrations of Site Contaminants Detected In Snce Soils During Phase I RI
/Results in milli:lIamsfkiloaraml
Backaround 5urface Soils In - 21 Burn Pond Surface Soils n=5 Surface Soils Outside B16n Pond (n - 16)
Previou! Number 01 Minimum Average Maximum Location 01 Number of Minimum Average Maximum Location 01 Number of Minimum Average Maximum Location of
ColC Dectections Concen- Concen' Concen- Maximum Dectections Concen- Concen- Concen- Maximum Dectections Concen- Concen- Concen- Maximum
tration tration tration Detection tration tration tration Detection tration htion tration Detection
VOI.AllLE COWOUN>S
Methylene Chloride N I'V I'V 1 0.31 J 0.31 0.31 J SS-OI,O" - 6' 2 0.016 0.02 0.024 5B-10,O" - 6'
Acetone N I'V I'V I'V NO 1 0.028J 0.028 0.028 J SB-13,O" - 6'
CerbonDisulfide N I'V I'V I'V NO NO NO
1,1-Dlchloroethene I'V NO ND ND ND ND
trans-1,2-Dlchloroethene ND ND ND ND ND ND
2 - Butanone N I'V ND 1 0.081 J 0.081 0.081 J S5-04,O' - 6' ND ND
Vinyl acelale ND ND ND NO ND ND
1,1,1- Trichloroethane ND ND ND ND ND ND
Bromodlchloromethane ND ND ND ND ND ND
1,2 -Dlchloropropane I'V ND ND ND NO ND
c<'s-1,3-Dlchloropropene ND ND ND ND NO ND
Trichloroethene N ND NO ND ND ND ND
1,1,2- Trichloroethane ND NO ND ND ND ND
Benzene N ND NO 1 0.83 0.83 0.83 S5-01,O' - 6' 1 0.19J 0.19 0.19J 5B-06,O" - 6'
Bromolorm I'V NO NO NO NO NO
4-Methyt-2-Pentanone ND NO 1 0.32J 0.32 0.32J S5-01,O' - 6' NO NO
2-He)Olnone ND NO NO ND 1'1> NO
Tetrachlaethene ND I'V ND ND NO NO
Toluene N ND ND 1 26 26 26 S5-01,O' - 6' ND ND
Chlorobenzene, N ND ND ND ND ND ND
Ethylbenzene N ND ND 1 0.34J 0.34 0.34J 55-01,0' - 6' ND ND
5tyrene ND ND ND ND ND ND
Xylene (T OlaO N ND ND 1 0.43J 0.43 0.43J 55-01,0' - 6' ND ND
trans-1 ,4-Dlchloro-2-butene ND NO ND NO ND ND
Ethyl methacrytate ND NO ND NO I'V I'V
1,2,3- Trichloropropane I'V NO ND NO ND ND
Ethanol I'V I'V ND NO ND NO
SEMIVOlAT1LE COWOUN>S
Phenol N ND NO ND NO ND ND
4- Methytphenol N ND ND 1 13 13 13 55-01,0' - 6' ND ND
Naphthalene N ND ND NO ND 3 0.041J 0.18 0.42J 5B-07,O' - 6'
4-Chloro-3- methylphenol ND ND 1 0.67J 0.67 0.67J 55-01,0' - 6' NO ND
2-Methytnaphthalene N 1 0.12J 0.12 0.12J 5S-13,O' - 6 1 1.1 J 1.1 1.1 J 55-01,0' - 6' 2 0.048 0.074 0.12J SB-07,O' - 6'
Acenaphthene N I'V NO ND ND 3 0.11 J 0.21 0.37J 5B-07,O' - 6'
Dbenzofu-an N ND ND NO ND 2 0;041 J 0.13 0.22J 5B-07,O' - 6'
2,4 -Dlnllrotoluene I'V I'V NO ND I'V NO
Diethylphthalate NO I'V NO NO 1 2.6 2.6 2.6 SS-II,O'- 6'
Fluorene N I'V I'V ND ND 2 0.12J 0.22 0.32J SB-07,O" - 6'
N-Nitrosodiphenylamine (1) I'V NO ND ND ND NO
Phenanthrene N NO NO 2 0.87 J 1.6 2.4 J 55-04,0' - 6' 11 0.057 J 0.54 2.7 J 5B-07,0' - 6'
Anthracene N ND ND 5 0.50J 0.74 1.4J 55-04.0' - 6' 7 0.046 J 0.21 0.64J 5B-07.0' - 6'
DI-n-butylphthalate N NO ND NO NO NO ND
Fluomnthene N 1 0.067 J 0.067 0.067 J 55-12,0' - 6 2 0.57J 1.6 2.6J 55-04,0'- 6' 14 0.045J 0.65 3.1 56-07,0'- 6'
Pvrene N 1 0.10J 0.10 0.10J 55-12,0' - 6 5 0.52J 1.4 2.6J 55-04,0" - 6' 14 0.043 J 0.53 2.4J 5B 07, 0" - 6'
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TABLE 1
(page 2 of a)
WIllIAMS PPE LINE COMPANY 1211-1 ST TERMINAL
BlflN PON> SlPERFUN> SITE
Summary 01 Concentrations of Site Contaminants Detec:ted In Strlace Soils Dwing Phase I RI
!Results In milliaramstkilnnram\
Backaround Surface Soils n=2 Burn Pond Surface Soils n 5 Surfaca Soils Outside Bwn Pond n - 16
Previou Number 01 Minimum Average Maximum location 01 Number of Minimum Average Maximum location 01 Number 01 Minimum Average Maxlmurr location of
ColC Dectections Concen- Concen Concen- Maximum Dectections Concen- Concen- Concen- Maximum Dectections Concen- Concen- Concen- Maximum
I1atlon !ration !ralion Detection I1allon !ration !ration Detection !ration !ration !ration Datection
Benzo(ajanttvacene 1 0.072 J 0.72 0.072 J SS-12. 0' - 6 1 1.0J 1.0 1.0 J S5-04.0' - 6' 12 0.043 J 0.37 1.5J 8B-07, 0' - 6'
Ctvysene Y 1 0.11 J 0.11 0.11 J SS-12. 0' - 6 1 1.1 J 1.1 1.1 J S5-04. 0' - 6' 13 0.039 J 0.27 1.3J 8B-07,O' - 6'
bis(2 - Ethylhexyl)phthalate Y 1 0.13J 0.13 0.13J SS-12. 0' - 6 1 0.79J 0.79 0.79J S5-01, 0' - 6' 8 0.051 J 0.20 0.46J SB-07, 0' - 6'
Benzo(b)fluoranthene Y 1 0.11 J 0.11 0.11 J 85-12.0' - 6 1 0.53J 0.53 0.53J 85-04. 0' - 6' 11 0.058 J 0.38 1.3J 8B-07.0' - 8'
SB-08. 0-6'
BenzoMfluoranthene Y 1 0.10J 0.10 0.10J 8S-12. 0' - 6 1 0.63J 0.63 0.63J S8-04, 0' - 6' 11 0.061 J 0.29 1.2 SB-07. 0' - 6'
Benzo(ajpyrene Y 1 0.090 J 0.090 0.090 J SS-12.0' - 6 1 0.63J 0.63 0.63J S5-04. 0' - 6' 12 0.038 J 0.35 1.4 SB-07. 0' - 6'
Indeno(I.2,3-cd)pryene Y 1 0.072 J 0.072 0.072 J S5-12. O' - 6 f\D f\D 8 0.059 J 0.22 0.73 8B-07,O' - 6'
Dibenz(a.h)anthracene f\D f\D f\D f\D 1 0.33J 0.33 0.33J 8B-07,O' - 6'
Benzo(g.h.~perylene 1 0.10J 0.10 0.10J 85-12.0'-6 f\D f\D 7 0.059 J 0.28 0.74 8B-08,O' - 6'
7.12-Dlmethybenzo(ajanttvace f\D f\D f\D f\D f\D f\D
DiDhenvlamine f\D f\D f\D f\D f\D f\D
PE811CI>E/AROClOR
COMPOUNDS
Heptachlor epoxlde Y 1 0.0011 J 0.0011 0.0011 J SS-13. O' - 6 f\D f\D 2 0.00074 J 0.0074 0.014J 8B 11,0' - 6'
Dieldrin N 1 0.0031 J 0.0031 0.0031 J 55-13. O' - 6 f\D f\D f\D f\D
Endrln N f\D f\D f\D f\D 1 0.020 0.020 0.020 8B-18, 0' - 6'
Methoxychlor N f\D f\D f\D f\D f\D f\D f\D
Endrin ketone 1 0.0074 Jr 0.0074 0.0074 Jr S8-12, O' - 6 f\D f\D 1 0.0039 J 0.0039 0.0039 J 8B-18. 0' - 6'
Endrln aldehyde f\D f\D 1 0.13JN 0.13 0.13JN 88-05.0' - 6' f\D f\D
alpha-Chlordane N f\D f\D f\D f\D 2 0.0019 J 0.0036 0.0052 J 8B-11,O'-6'
gamma-Chlordane N f\D f\D f\D f\D 3 0.0011 J 0.010 0.019 SS-08,O' - 6'
Aroclor -1254 Y f\D f\D f\D f\D 13 0.049 J 0.77 7.5 88-14,0' - 6'
HERBICIDE COMPOUNJS
2,4-D f\D f\D f\D f\D f\D f\D
2,4-DB f\D f\D f\D f\D f\D f\D
2.4,5- T f\D f\D 1 0.0083 J 0.0083 0.0083 J 8S-01, 0' - 8' 1 0.0002 J 0.0002 0.0002 J 8B-08, 0' - 6'
2,4,5-lP (Silvex) f\D foD foD foD '1 0.00038 J 0.00038 0.00038 J SB-11,O'-8'
Dalapon 1 0.0029 J 0.0029 0.0029 J SS-13. 0' - 6 f\D f\D f\D f\D
Dicamba f\D f\D f\D f\D f\D f\D
Dlchloroprop f\D f\D f\D . f\D f\D f\D
Dinoseb foD foD f\D f\D f\D f\D
MCPA foD foD foD f\D foD foD
MCPP f\D foD foD f\D f\D foD
DIOXIN AND FURAN
Total HxCDD ~ ~ f\D f\D ~ ~
1234678-HpCOD ~ ~ 2 0.00004 0.00007 0.0001 0 8S-01, 0' - 6' ~ Nil,
Total HpCDD ~ Nil, 2 0.00004 0.00013 0.00021 SS-OI,O' - 6' Nil, Nil,
CCDD ~ Nil, 1 0.00082 0,00082 0.00082 S8-01,O' - 6' Nil, Nil,
TotalTCDF ~ Nil, 2 0.00003 0.00004 0.00004 88-01,0' - 6' Nil, Nil,
TotalPeDCF ~ Nil, 2 0.00014 0.00027 0.00039 88-03,0' - 6' Nil, Nil,
234678-HxCOF ~ ~ 1 0.00001 J 0.00001 0.00001 J 88-03,0' - 6' Nil, Nil,
Total HxCDF ~ Nil, 2 0.00015 J 0.00017 0.00018 J S8-01, 0' - 6' Nil, Nil,
1234678-HpCOF ~ Nil, 2 0.00001 M 0.00002 0.00002 8S-01. 0' - 6' Nil, Nil,
Total HpCDF ~ ~ 2 0.00004 0.00008 0.00012 85-01,0' - 8' Nil, Nil,
CCDF ~ Nil, 1 0.00006 0.00006 0.00008 88-01,0'- 6' Nil, Nil,
lPH-IR
lPH-IR 1 34 34 34 88-13, O' - 6 5 190 1140 4000 S8-05,O' - 6' 10 33 87 360 SB-09,O' 6'
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TABLE 1
(page 3 of 3)
WILLIAMS Pf'E LINE COMPANY 12TH STTERMINAl
BURN PON) SlPERFUtIJ SITE
Summary of Concentrations of Site Contaminants Detected in Slriace Soils During Phase I RI
/Results in milliarams/kil""raml
Backaround Surface Soils In - 2 Burn Pond Surface 80ils n = 5\ 8urface 80ils Outside Burn Pond In -16\
Previous Number 01 Minimum Average MaximulT location of Number 01 Minimum Average Maximum location of Number 01 Minimum Average Maximum location of
CofC Dectections Concen- Concen Concen- Maximum Dectections Concen- Concen- Concen- Maximum Dectections Concen- Concen- Concen- Maximum
tration !ration !ration Detection !ration !ration !ration Detection !ration tration tration Detection
TOTAL METAlS
Aluminum 2 9230 10400 11500 J SS-13, 0' - 6 5 7990 10800 13200 S5-01,O' 6' HI 2080 8550 17700 S5 11,0' 6'
Antimony Y I'.[) I'.[) I'.[) N) I'.[) I'.[)
Arsenic Y 2 5.9 6.6 7.2 J S8-12, 0' - 6 5 5.5J 13 22.9J 88-03,0' - 6' 18 5.1 J 26 119J 88-08,0' - 6'
Barium N 2 161 183 205 SS-12, 0' - 6 5 134 153 178 SS-01,O' - 6' 16 74.9J 201 430J SB-10, 0' - 6'
Beryllium N 1 0.58 0.58 0.58 SS-13, 0' - 6 I'.[) N) 2 0.13J 0.26 0.4 SB-12, 0' - 6'
Cadmium N 2 0.87J 0.99 1.1 J S8-04, 0' - 6' 11 0.29J 0.7 2.2
Calcium 2 7360J 9880 12000 8S-12.0' - 8 5 4380 18100 55900 SS-03,O' - 6' 16 6800 25500 71600 J 8B-08,O' - 6'
Clvomium N 2 12.4 13.7 14.9 88-13,0' - 6 5 20.5 23 27.2 88-01. 0' - 6' 16 5J 14 26.6 SB-10, 0' - 6'
Cobalt N 2 7.6 9.7 11.8 SS-13, 0' - 6 5 8.3 . 10 11.8 SS-04,O' - 6' 16 3.7 9 13.7 SS-11,O' - 6'
Copper N 2 14.7 14.9 15 SS-12. 0' - 6 5 22.2 30.8 38.3 SS-04,O' - 6' 16 4.8J 16.2 49.6 S8-11,O' - 6'
Iron 2 15300 15800 15900 8S-13, 0' - 8 5 14200 23300 51800 S5-04, 0' - 6' 16 75300 J 15800 28300 S8-",O' - 6'
lead N 2 21.2 .22.4 23.6J 5S-12, 0' - 6 5 148 222 436 88-04, 0' - 6' 16 9.4J 48.8 122 8S-",O' - 6'
Magnesium 2" 3550 3790, 4030 J 88-13,0' - 6 5 3050 J 3840 4690J 88-03,0' - 6' 16 3260 7600 21500 J 88-06, 0' - 6'
Manganese V 2 839 940 . 1040J 88-13,0' - 6 5 543 934 1450 88-03,0' - 6' 16 823J 1910 8130 J 88-10,0' - 6'
Mercwy N 2 I'.[) I'.[) 1 0.39 0.39 0.39 88-04,0' - 6' 1 0.13 0.13 0.13 8B-06, 0' - 6'
Molybdenum 2 1.5 1.75 2 88-12,0' - 6 5 1.1 2.3 5 8S-04,O' - 6' 16 0.87 1.9 3.9J 8B-10,O' - 6'
Nickel N 2 17.1 .19.5 21.8 88-13,0' - 6 5 17.4 22.4 26.5 88-04,0' - 6' 16 11 20.2 32.5J SB-10,O' - 6'
Potassium 2 1730 193'0 2130 8S-12, 0' - 8 5 958 1290 1810 S8-01,O' - 6' 16 432 1470 3030 88-11,0'- 6'
Selenium N 1 0.4 0.4 0.4 8S-12, 0' - 6 3 0.28 0.38 0.53 8S-01,O' - 6' 9 0.2J 0.5 1.2 8S-1', 0' - 6'
Silver N I'.[) I'.[) I'.[) I'.[) I'.[) I'.[)
Sodium 1 304 304 304 SS-12, 0' - 6 5 186 219 316 88-01,0' - 6' 10 " 80.2 181 359 88-11,0'-6'
Thallium N I'.[) I'.[) I'.[) NO 1 0.29 0.29 0.29 88-10,0'- 6'
Vanadium N 2 19.9 24.1 28.3 8S-13, 0' - 6 5 20.1 24.2 29 88-01,0' - 6' 16 7.4J 22.5 44.7 SS-",O' - 6'
Zinc N 2 62 J 70.1 76.1 8S-12,O' - 6 5 91 112 135 89-01 0' - 6' 16 25.7J 104 388 98-110'-8'
Only dectect compounds ate listed. Minimum detections reported are above ihe analysis detection limit.
I'.[) = Not Detected
J = Estimated Concenlration
IN = Numerical Value Represents Approximate Concentration
M = Estimated Maximum Concentration
. n = number of samples
Previous C ofC = Previous chemical of concern as repated In the EPA Conceptual Site Model, April 16, 1992. Blanks indicate lhatthe compound was not Included In the April 18. 1992 report. Y = yes, N = no
Duplicate samples were collected during the Phase I RI. Duplicate detections were not Included In the Number of Detections, however, duplicate results were used to calcuaJate the Average Detection.
-------
TABLE 2
(Pago 1 01 2)
WIlLIAMS PIPE UNE COWANY 12TH ST TERMiNAl
BURN POM> SUPERFUND SITE
SUmmory 01 CcncmlrBllonsof Silo Cmlomhmts DeIBCtod h SUbsurfoco Soils Durhg Phoso I RI
!Results In mllllgnmsJ\dlogram)
Bockground Subsurtaca Soils n = 21 8um Pond Subsurfaca 5011s (n = 15 Subsurfoco Soils Outsldo Bum Pond . (n = 109)
P,l!YIous Numb., 01 Minmum . A..,aga Maximum Location of Number 01 Mininum A..,ogo Maximum Locallon 01 Number 01 Mlnmum ~..,og. Maximum Localla1 01
CorC Oetactlons Concen- Concen- Goncen- . Maximum Oolec:llons ConcC!f1- Concen- Concen- Maximum Dectecl10ns Coocen- Cmcan- Cax:en- Maximum
.ratlon ',alien hatlcn Ccncanlratlon Irallon Ir81100 ',aUm Concantratla1 tratlon tralla1 tratlon Concantratla1
VOLATILE COWOUMJS
M~YJana O1lorid. N NO O.O~~~ 6 0.16J 6.4 43J S~-04, 3.0 3.4' 25,000 0.002 0,930 211 56-07,10 -15
Acelone N 9 0,006 J 0.011 58-26,46' - 50' I 32J 32 32J 58-01,02'-04' 20.000 0.001 J 1.500 19J 58-11,10'-15
Carbon Olsu"lda N I 0.005 J 0.005 O.005J 58-26, 58' - 60' NO NO 1.000 O.003J 0.003 O.003J S8-1',45'-5O'
I, I-Oknloroothen. NO NO NO NO 1.000 0.002 J 0.002 0.002 J S8-13,05'-111
trens-I,2-0Ichloroethena NO NO NO NO 2.000 0.13J 0.140 0.14J 58-QQ,05'-111
2-Butenona N 4 O.029J 0,053 0,075 J 58-27,48' - SO' 4 6.6J 24 72J S8-01,02'-04' 13.000 0.029 J 7,000 II 58-11,05'-111
SB-I',3(/-35'
Vhyl acolota NO NO I 36J 36 36J 58-01,04'-06' NO NO
1,1,1- Trlchloroolhene NO NO NO NO 1.000 o.oa; J 0.005 O,Oa;J 58-13,05'-111
8rcmodlchloranelhen. NO NO NO ND 1.000 0.14J 0.140 O,14J 58-QQ,05'-111
1,2-01ct11orcprcp8l1a NO NO NO No 2.000 . 0.14J 0.150 0.16J S8-09, 15'-2(1
cl.-I,3-0knlorcprcpane NO NO NO ND 2.000 0.14J 0.220 0.26J S8-QQ,15'-2(/
TrlchlOfoethane N NO NO NO NO 2.000 0.14J 0.150 0.16J S8-09, 15'-2(1
1,1,2- Trlchloroolh8l1a NO NO NO NO 1.000 0.16J . 0.18:1 0.20J 58-09,15'-2(1
8enzene N NO NO 11 0.26J 6.7 23J S8-01,04'-06' 7.000 0.14J 0.740 3.7J S8-07,10'-15
8rano/orm NO NO NO NO 1.000 0.21J 0.210 0.21J 58-09, 15'-2(1
4-Mathyl-2-Pant8l1one NO NO I 2.IJ 2.1 . 2.1J S8-05,OI'-01.5 2.000 O.OO2J 0.005 0.007 J S8-13,oo'-05
2-Haxenone NO NO NO NO 1.000 0.022 0.022 0.022 S8-15,oo'-05'
Telrechlorethone NO NO NO NO 1,000 O,16J 0.18:1 O,16J 58-09,15'-2(1
Toluena N 2 0.001 J 0.002 O.OO2J 5B-26, 54' - 55' 15 3.2J 52 200J 5B-01,04'-06' 22,000 O.22J 4.900 44.000 58-07, 10'-15'
011010bB1zene N I 0.001 J 0.001 O.OOIJ 58-27, 15' - 30' NO NO 2.000 0.17J 0.180 0.20J S8-09, 15'-2(/
EhylblnZene N 1 0.001 J 0.001 0.001 J S8-27, 39' - 40' 15 2.2J 22 57J 58-01,04'-06' 29.000 0.016J 4.700 23.000 58-18,15'-2(1
5tyrene NO NO NO NO 3.000 0.13J 0.100 O,26J 58-QQ, 15'-211
Xylona (Tala\) N 5 0.002 J 0.036 0.16J 5B-26, 10' - 15' 15 5.3J 69 240J 5B-05,03'-03.5 35,000 0.000 J 15.000 60,000 58-06,10'-15'
trens-I,4-01chIoro- 2-buten a NO NO NO NO 2.000 7.2J 9.100 11.000 S8-09, 20' -25
Ehyl mathocrytato NO NO 6 0.66J 1.8 2.8J 58-02, 04' -05 7.000 O.40J 1.200 2.500 S8-09, 20' -25
1,2,3- Trlchloropropen. NO NO NO NO 1.000 0,16J 0.160 O.HIJ 5B-07,OO'-05'
Eheno/ 3 0.011J 0.17 0.40J 5B-26, 58' - 50' 1 10J 10 10J 58-03 00'-02' 2.600 16J 610.000 1200J 5B-I',30'-35'
5EMIVOLATILE COWOUNDS
PhenOl N N~ ~~ 3 6.9J 19 32J 88-01,00 - 02' ~g NU
4-Mathylphenol N NO NO NO NO
N8IJhth.leno N NO NO 15 2.7J 53 210.000 58-01,00' - 02' 28.000 0.000 6.900 44.000 8B-07,10'-I5'
4 -01loro- 3 -methytphonol NO NO NO NO NO NO
2-Mathylnaphthalena N NO NO 15 10,000 169 620.000 8B-01, DO.' - 02' 33.000 . 0..039 J 23.000 110.000 88-07, 10'-15
ACanephhen a N NO NO 11 2.3 8.5 22J 88-01,04'-0.6' 29 0..052 J 1.0 4.8 S8-18,2O'-25
OibenzotJren N NO NO 11 2.8 9,7 28J 58-01,02' - 04' 21 0.088 0.98 3.8 S8-18,2O'-25
2,4-0inltralolJana NO NO NO NO 1 1.7J 1.7 1,7J 8B-09,10'-I5'
Olathylphlhal.ta NO NO NO 'NO NO NO
Fluoreno N NO NO 12 4.0 16 33J 8B-01, 0.2' - 04' 31 o..080J 1.8 7.9 S8-16,2D'-2S'
N-Nilrosodlrnenylamh. (1) NO NO NO NO 3 0.36J 0..91 2.o.J 8B-o.9,15'-2(1
Pherurlthrcne N NO NO 15 5.1J 81 190 58-01, DO' - 02' 36 0.081 8.4 24J 8B-07,10'-I5'
Anhracena N NO NO 1 7.3J 7.3 7.3J 5B-04, 02' - 04' 4 O.038J 0.40 0.62 58-IS, 00' -OS'
Ol-n-bufytrnthatoto N NO NO 3 3.9J 10 19 S8-05, 02' - 0.4' 5 0..044 0.0f39 0..0.78 8B-15,10'-I5',
5 5B-15,30'-35'
Fluor""thona N NO NO NO NO 0.062 J 1.1 8.3 88-15,00'-05'
. Pyrena N NO NO .4 2.0 5.9 15J S9-01, 00' - 02' 17 0.043 J 0.66 5,2 88-15,00'-0.5'
9enzo(o)8I1flrocano NO NO NO ND 4 0.065 0.83 3.1 59-IS, 00' -05'
Chryseno Y NO NO NO NO 4 0.083 0.88 3.3 58-15,00'-05'
bls(2-Ehylhexyl)phthe/ata Y 13 0.041 J 0.8 2.7J 58-26, 50' - 55' NO NO 61 0.049 J 2.1 8,7 59-15,45'-50'
Benzo(b)fluoranlhena Y NO NO NO NO 4 0.046 J 0.72 2.7 SB-15,oo'-05'
Benlo(k)fluoranlhen. Y NO NO NO NO 3 O.045J 0.94 2.7 S9-15,Oo.'-05'
8enlo(0)pyrana Y NO NO NO NO 3 0.0.43 0.82 3.1 S9-15,oo'-05'
indeno(l,2,3-cd)pryena Y NO NO NO ND 2 0.047 0.72 . 1,4 SB-15,oo'-o.5'
Olbenz(a,h)enthracone NO NO NO NO 1 0.86 0.68 0.86 5B-15,oO'-05'
Benzo(9,h,ijperytene NO NO NO NO 1 1,4 1.4 1.4 S8-15,oo'-05'
7,12-0Imelhylbenzo(0)""lhroco NO NO NO NO 1 0.26 0.28 0.28 S8-15,oo'-o.5'
Olphenytamna ND NO NO NO 1 0.32J 0.32 0.32J 58-14,10'-15'
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T A8LE 2
(Page 2 01 2)
WILLIAMS PIPE LINE COMPANY 12TH 8T TERMINAL
BURN POND SUPERFUND 81TE
Slrnmary 0' Concentratlonso' Site Contaminants Detected In Stblurfaca SoU. During Ph.'. I RI
fRe,uft,1n mlUlaram'/kIIOaraml
Backtlround Slblurface Soils In - 21 Burn Pond Slbsurf808 SoDs In = 15 Stbsurface 5011, Outside Burn Pond n a 109\
Prevtous NtA"T1bero' Mlnrm.m Average Maxi'nun Location 0' Nln\ber of Mlninun Average Maxinwn LoaUo" o' NU11be, o. Mlnrnum Average Maxhn.m Location o'
CorC DetecHaM Concen- Concen- Concen- Maxi'nt.m Detections Concen- Concen- Concen- Maxmum Oectectlon. Concen- Conoen- COnolln- Maxnnm
Iration tralion .r.Uon Concen1ratlon .raUon .ratlon 1'815on Concentration IraUon tration tratlon Concentl.Uon
PE8 TlCIDEIAROCLOR
COMPOUNDS ND ND
Heplachlor epo.lda Y ND ND ND ND 1 0.0011 J 0.0011 0.0011 J 8B-08,oo' - 05'
Dieldrin N ND ND ND ND ND ND
Endrln N ND ND ND ND 2 O.0038J 0.0039 0.004J SB-De, 20' - 25'
Methoxyd1Jor N ND ND ND NO 1 O.0083J . 0.0083 0.0083J SB-09, 40' - 45'
Endrtn ketone NO NO ND NO NO NO
Endrln aldahyde ND NO ND NO NO ND
o~ha-Chlon1ono N ND NO ND ND 1 0.00059 J 0.00059 0.00059J 8B-08,oo' - 05'
gamma-Chlordane N ND NO NO NO I 0.00013 J 0.00013 0.00013 J 8B-08, 00' - 05'
Noelor 1254 V NO NO ND NO 4 0.038J 0.08 0.094J 88-12 00' - 05'
HERBICIDE COMPOUNDS
2,4-D 1 0.0012J 0.0012 0.0012J 8B-21, 15' - 30' NO ND 8 0.0044 J 0.0131 0.019J 88-08,05' - 10'
2,4-08 I 0.0022J 0.0022 0.0022 J 8B-28, OS' - 10' 3 0.021J 0.053 0.010 J 88-01,00' - 02' 2 O.ooIJ 0.0015 0.0019J 8B-13, 05' - 10'
2,4.5- T 4 0.0012J 0.0015 ' 0.0021 J 8B-21, 20' - 25' NO NO 9 O.OOO2J 0.0001 O.OOU J 88-14,30' - 35'
2,4,5- TP (8wo'" 3 0.00031 J 0.00068 0.0012J 8B-21,2O' - 25' NO ND 7 0.00013J 0.00034 O.OOIJ 88-01,15' - 20'
Oa""on 2 0.0041 J 0.0055 0.0084 J 8B-28, 10' - IS' ND ND ND ND
Oleambo 8 0.0002J 0.0005 O.ooIJ 8B-28, 25' - 30' 3 0.0039 J 0.010 0.018J 88- 03, 00' - 02' I 0.0008J 0.0008 0.0008 J 88-15,20' - 25'
Olc:hloroprop 8 0.0039 J 0.0013 O.OIIJ 8B-21, 05' - 10' ND ND 4 0.0018J 0.0043 0.0091 J 88-De, 15' - 20'
Olno,'" NO ND ND NO NO NO
MCPA I 0.20J 0.20 0.20J 8B~21, 05' - 10' 8 2.5J 11 32J 88-04,02' - 04' 10 0.12J 0.91 2.5J 8B-08, 20' - 25'
MCPP NO ND ND NO ND ND
DIOXIN AND FURAN
Toiol HxCOO NA NA 1 0.00001 0.00001 0.00001 88-03, 00' - 02' NA NA
1234818-~COD NA NA 5 0.00001 0.00003 0.00005 88-01,02' - 04' NA NA
Tota' HpCOD NA NA 5 0.00001 0.00003 0.00005 88-03,00' - 02' B-01,02' NA NA
OCDD NA NA ND NO NA NA
TOlal TCOF NA NA 2 0.000005 0.00001 0.00003 88-03, 00' - 02' NA NA
TOlal PoOCF NA NA I 0.00001 0.00001 0.00001 8B-03, 00' - 02' NA NA
234818-HxCDF NA ' NA NO ND NA NA
Totol HxCOF NA NA 4 0.00001 J 0.00005 0.00008J 88-03,00' - 02' NA NA
1234818- ~COF NA NA 4 0.000004 0.00005 0.00022 88-01,00' - 02' NA NA
Tolo' HpCDF NA NA 4 0.000004 0.00008 0.00022 8B-01,oo' - 02' NA NA
OCOF NA NA 4 0.000001 M 0.00001 0.00024 8B-01,oo' - 02' NA NA
TPH-IR
TPH-IR . NO ND .5 1900 31100 200000 8B-02 02' - 04' 43 51 4080 23000 88 01 10' - IS'
TOTA METALS
AI\ITIlnwn 21 1410J 12~ 19600J 8B-26, 35' - 40' 15 3120J 1060 11800 88-01,00' - 02' 109 812 3120 11800J 88-15,45' - 50'
Ammony V 2 2.3J 3.2 4.2J 8B-21, 10' - 15' I 8.3J 8.3 8.3J 88-04,00' - 02' 3 2.5J 2.8 3J BB-18, 30' - 35'
Arsenic V 21 2 5.1 14.3 8B-28, 20' - 25' 15 1.5J 10.9 28.1J 88-01,00' - 02' 108 2 8.1 20.8J 8B-13, 35' - 40'
88,1\.111 N 21 54.4 130 264 8B-21, 05' - 10' 15 89.9 129 248 88-01,02' - 04' 109 13.3 108 1340J 88-01,40' - 45'
Berylilum N NO ND NO NO II 0.08 0.24 0.52 88-10,00' - 05'
Cadmium N 10 0.29 0.41 0.93J 88-26,45' - 50' 13 0.19 I 2.9J 8B-01,oo' - 02' 41 0.28J 0.84 2.4 88-18,45' - 50'
Colclun 21 4880 J 42800 82100 88-21,30' - 35' 15 6540 J 24800 10looJ 88-05,04' - OS' 109 l100J 49000 112000 J 88-13,05- 10'
Chrom Ium N 21 4.9J 13.8 20.8 8B-28, 35' - 40' 15 10.3 34 124 88-01,02' - 04' 109 1.0J 8.2 23.8 88-15,45' - SO'
Cobaft N 21 3.1J 8.9 12.1 8B-28,05' - 10' 15 4.4 8.8 18 8B-04,OO' - 02' 109 1.8 5.6 20 8B-IO, 45' - 50'
Copper N 21 4.1J 12.6 29.1 8B-28, 45' - SO' 15 12.5 41.1 110 8B-01, 00' - 02' 109 2J 8 21.3 8B-08, 45' - 50'
tron 21 8290 12900 20200 8B-28, 05' - 10' 15 1510J 23800 102000 J 8B-04,OO' - 02' 109 3190 J .10400 21000 J 8B-11, 45' - 50'
Loed N 21 2.9J 8.9 14.8J 88- 26. 35' - 40' 15 61.5J 318 1210 8B-01.02' - 04' 102 1.5 1.2 31 J 88-08,00' - 05'
Magne,lum 21 3300J 10500 20400 88-28, 10' - 15' 15 3180 6590 18100 8B-05,04' - 08' 109 404 1360 31800J 8B-10, OS' - 10'
Mangane.. Y 21 163 151 2590 J 8B-28, 10' - IS' '5 611 1000 1500 8B-04, 04' - 08' 109 93.9 745 3200J 88-08,30' - 35'
Mercury N 2 0.11 0.12 0.12 8B-21, 10' - IS' 2 0.41 0.53 0.59 8B-01, 00' - 02' 2 0.11 0.21 0.31 8B-12, 45' - 50'
MO„Jdenu-n 21 0.59 1.5 4.1 8B- 28, 40' - 45' 11 0.92 2.9 13 8B-04, 00' - 02' 81 0.85 2.0 8.0 88-08,40' - 45'
Nickol N 21 9.4 11.2 28.8 8B-28, 05' - 10' 15 9.1 J 19.5 41.9 8B-04, 00' - 02' 105 4 13.2 39.8 88-09, 45' - 50'
Potasst\m 21 314 1220 2910 8B-28, 35' - 40' 12 383 931 1530 68-01.00' - 02' 83 149 859 2040 8B-15, 45' - 50'
S.lenll.nl N 8 0.28J 0.94 2.9J 88-28,45' - SO' 4 0.08 0.21 0.38 8B-01, 02' - 04' 38 0.11 2.3 29.9J 8B,.12, 45' - 50'
8livo, N NO NO NO ND 1 0.89 0.89 0.89 88-01,40' - 45'
80dlum 16 143 209 301 8B-21, 15' - 20' 5 19.9 141 253 8B-01, 02' - 04' 84 60.4 138 628 8B-13, OS' - 10'
Thallium N 9 0.21 0.3 0.44 88-21, 10' - 15' 2 0.22 0.28 0.29J 18B-01, 02' - 04' 7 0.25 0.3 0.39 8B-18, 45' - 50'
Vanadhn N 21 1.3 21.1 54.9 88-26,40' - 45' 15 8.9J 11.2 29.8 8B-01, 00' - 02' 109 4.8J 16.1 54.5J 88-15,45' - 50'
Zinc N 18 19.8 40.4 59.2 8B-26 05' - 10' '5 48.5 107 245 8B-01 02' - 04' 109 10J 28.8 82.4 8B-18 40' - 45'
On~ dected compounds afelisled. Mlnw",xn detedlons reported are above the analysis detedlon Imh.
NO a Not Oetectec:t
J = E.lmated Concentration
M = E,.mated Maxinwn Concentration
n J:I approximate nt.mbe, of SIImpl.. .
Previous C o' C = Previous ch8mk:a1 otconc:ern'l reported in the EPAConceptual Site Model. AprU 10, 1992. Blanks indicate thai the compound we. not tncIuded In the Aprll'S. 1892 repon. Y = Y", N 1:1 no .
Dl4Jlicate .."pl.. we,. cobeded during the Pha.el RI. D....,licate detections were not Induded In the N...-nber 01 Oeted50nl, however, d(4)licat. relunl were used to calcualete the Average Detection.
-------
TABLE 3
. (page 1 at 2)
WlWAM~ PIPE UNE COMPANY 12th ST TERMINAL
. BURN POND SUPERFUND SITE
Summary at Chemical Concentrations of Compounds Detected in Groundwater Samples Collected
During Phase I. Phase II. and Previous Investigations
(Results in microgramsl1ter
Previous (Non-Validated) Ground-water Samples RI (Validated) Ground-_ter Samples
ANAl YTES Minimum Maximum Location of Maximum Minimum Maximum Location of Maximum
Dectection . Dectection Dectection Dectection Dectection Dectection
ualL ualL uglL uglL
VOLATILES
Acetone 6J 170 EPA-4, 2/90 41 B 2500 B-4, 11/87
Benzene 0.7 J 2900 1-12, 19/88 1 5400 P-06, 9/92
Bromochloromethane NA NA 12 12 . EPA~3, 11.187
Bromodichloromethane . 1 27 Crame~s, 7/88 5 .::11" ... i MW -49;1 0;93:
2-Butanone NO NO 57 B 578 B-1,3/87
n-Butylbenzene NA NA 2 RW":' 5;1 0/93
Carbon Disulfide 9 17 EPA-3, 8/88 NO NO
Chlorobenzene 3.5 1:732050 8-4, 3/87 NO NO
Chloroform 0.5 J 73 Cramers.7/88 0.98 32 ...MW;;:49;io/93:..
1.2-Dibromoethane 6J 6J P-06, 9/92
Dibromochloromethane 0.4J 15 Cramers. 7/88 1 6 EPA-3, 11/87
, .2- Dichlorobenzene NO NO 10 J 10 J 8-10,11/87
, ,1 - Dichloroethane 0.7 J 0.7 J 08-12R.2/90 1 1 OB-12R. 9/92MW-430. 9/92
1 ,2 - Dichloroethane 0.5 J 47 J MW-440.2/90 2 86 P-06. 9/92
cis-1.2-Dichloroe!hene 2 2 MW-430, 9/92
1.2-Dichloropropane 4 4 MW-440.2/90 NO NO
Ethylbenzene 8.8 2800 1-12.10/88 1 2100 P-06. 9/92
Isopropylbenzene NO NO 1 66 . P-06, 9/92 ..
p-lsopropyltoJuene NA NA 2 :.:.:S:J. .:.. MW -'43D;io/93:
Methylene Chloride 0.9 J 100 8-2.3/87 1 8,J 78 B-12.11/87
Naphthalene NA NA 2 8600 P-06. 9/92
n-Propylbenzene NA NA 1 180 P-06, 9/92
T etrach loroethene ND NO 8J 8J B-2. 11/87
Toluene 0.2 J 2900 1-12.10/88 0.6 B,J 2200 P-06, 9/92
, , 1,1 ,-Trichloroethane 0.3 J 2J MW-57,2/90 0.8 0.8 OB-12R,9/92
, ,2.3 - Tichloropropane ND NO 1 270 P-06, 9/92
, ,2.4 - Trimethylbenzene NA NA 00.68 1400 P-06. 9/92
, ,3.5 - Trimethylbenzene NA NA 2 550 P-06. 9/92
Xvfenes C!olaO 0.5 J 4500 1-12,10/88 :1:6 6900 P-06, 9/92
SEMIVOLATILES
Acenaphthene ND NO 1 600 J B-2,11/87
Acenaphthylene 290 290 8-2, 3/87 NO NO
Benzoic Acid NO NO 1 50 .. PZ92-:04,.10/93 .
bis (2 -ethylhexyl) phthalate 3J 1000 8-1,3/87 4J 63 EPA-4, 11/87
Cyclohexane (C6H12) NA NA 4J 33 J B-2, 3/87
Oibenzafuran ND NO 1 590 J B-2, 11/87
Oi -n- butyl phthalate NO NO' 1 3 Burn Pond, 9/92
Ethyl methyl benzene NA NA 26J 200 J 8-1,3/87
Fluoranthene ND NO 130 130 B-1,3/87
Fluorene 1 3600 8-1,3/87 . 1 950 J B-2. 11/87
2-Methylnaphthalene 33 48 1-12,10/88 1 11000 J B-2. 11/87
2-Methylphenol NO NO 1 130 B-1,3/87
. .
4-Methylphenol NO NO 2 120 PZ92-04;10/93 .
Naphthalene 1 J 19000 B-1,3/87 6 3700 J B-2, 11/87
2-Nitrophenol ND NO 120 120 8-1.3/87
Phenanthrene 1 J 11000 B-1,3/87 1 2400 J B-2. 11/87
Phenol NO NO 2J 680 SW Tours, 11/87
Phthalate NA NA 360 J 390 J 8-1. 3/87
Pyrene NO NO 3J 68 B-1. 3/87
-------
TABLE 3
(page 2 of 2)
WILLIAMS PIPE LINE COMPANY 12th ST TERMINAl
BURN POND SUPERFUND SITE
Summary of Chemical Concentrations of Compounds Detected in Groundwater Samples Collected
During Phase I, Phase II, and Previous Investigations
esults in micro ramsJlter
Non-Validated Ground-_ter Samples
Minimum Maximum Location of Maximum
Detection Detection Detection
ulL' ulL
ANAL YTES
0.015
ND
ND
0.02
ND
ND,
ND
0.0064
0.087
ND
0.085
0.018
0.23
0.044
ND
NA
9.80 J
41.1
2.1 J
88.4 J
0.2
0.2 ,
78000
2
2.9J
2.2 J
60
2
20900
3.3J
9.5
NA
ND
530
2.2 J
2.2 J
4900
17
30
0.082
ND
ND
0.02
ND
ND
ND
0.1
0.18
, ND
0.085
0.057
0.7
0.044
8-10,7/88
B-12,7/88
8-10,7/88
B-10,7/88
B-10, 7/88
B-10, 7/88
B-10, 7/88
8-9,7/88
Validated Ground-water Samples
Minimum Maximum Location of Maximum
Detection Detection Detection
u IL ug/L
0.3 J
0.09
0.4 J
1.0 J
0.5
3J '
0.40J
0.30J
0.1
0.10 J
0.20 J
<1.05 J
ND
ND
0.02J
{:a.o:!\I':
324
42J
/",8",
35.4 '
ND
3.2 J
24300
6
11.7
8.7 J
38J
0.64 J
3820
7.3 J
0.24
9.7
12 J
658J
2.2J
ND
1680
7.3
5.7 J
/~'r:J>
0:;:49,
t~4.:J
,'::'();13,
,~jjg.7 '."
'.'O,086J'
PESTICIDES
Aldrin
Alpha-BHC
Beta-BHC
Gamma-BHC
Gamma Chlordane
4,4-DDD
4,4-DDT
Dieldrin
Endosulfan I
Endosulfan Sulfate
Endrin
Heptachlor
Heptachlor Epoxide
Methox Ichlor
HERBICIDES
2,4-DB
Dicamba
METALS
Aluminum
Antimony
Arsenic
Barium
Beryllium
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Mercury
Molybdenum
Nickel
Potassium
Selenium
Silver
Sodium
Vanadium
Zinc
FURANS/DIOXINS
aCDF
TCDDs (Total)
PeCDDs (Total)
HxCDDs (Totalr
HpCDDs (Total)
1,2.3.4,6,7,8 HpCDD
aCDD ,
Only detected compounds listed
Shading indicates results from Phase II RI
ND: Not Detected
NA: Not Analyzed
Source: Phase II Investigation Report
ND
NA
5500
41.10 J
180
6900
0.56J
2.2
176000
12000
19
57
45000
30
77300
33000
9.5
NA
3200
13000
7.40J
4.70J
61000
17
80
P-1, 1/89
MW-44D, 2190
8-1,3/87
B-2,3/87
MW-44D, 2190
MW-3, 10/88
MW-57,2I90
P-1,1/89
P-1,1/89
P-1,1/89
P-1,1/89
8-1,3/87
MW-57,2/90
P-1,1/89
8-4,3/87
Westegaard, 10/88
P-1,1/89
MW-65,2/90
MW-57,2I90
EPA-4,8/88
P-1,1/89
EPA-4,8188
ugJI: Microgram per liter
J: Quantitation estimated
B: Compound detected in associated blank
, 1.0 J
0.09
1.0 J
1.0 J
3
3J
3J
0.30 J
1
1.0 J
0.20 J
0.90 J
ND
ND
9.6 J
"0:02J
47600 J
90
" ..:"394,::,,,..
22400 J ..
ND
7J
649000
180
125
214
330000
176J
174000
17200
0.8
102
268 J
26200
13.8 J
ND
69100
396J
29300
0.072J
0.2 "
0.49
',:0.23,
'0.13"
,0.0,97
0.42:"
8-2,11/87
EPA-4, 11/87
B-2. 11/87
8-2,11/87
B-418-10, 11/87
B-2,11/87,
B-2,11/87
B-1018-12,11./87
EPA-2,11/87
6-2,11/87
B-10,11/87
B-2, 11/87
EPA-1,9/92
:'D8-",12R: 10/93,
B-08,9192
B-418-12, 11/87
".,.,MW:::'12~l0I93: :"
't.,.fW~S8. 9192' ...",.
MW-58,9/92
P-4R,9192
MW-58, 9192
MW-58, 9192
MW-S8,9192
DB-12R,9/92
MW-58, 9192
P-4R,9192
MW-47,9192
B-2/MW-28,11/87
P-06,9192
MW-58, 9192
Watson, Coo 11/87
P-06,9192
EPA-4,9/92
MW-58,9192
Watson, C., 11/87
'MW':"S8;10/93 '
, ,B-8~ 10/93 '
, 8-8,,10/93
.' 'B-"8;'10/93:
'MW-'S8. ,10193::
,'MW':58; 10/93:"
-------
TABLE 4
WILLIAMS PIPE LINE 12TH STREET TERMINAL
SUPERFUND SITE
Summary of Total Arsenic Detected in Groundwater
During the Phase I RI, Phase II RI, and Previous Investigations
. . Results in micrograms/liter)
MonitorWell Mar-87 Nov 87 AUQ' 88 Oct 88 Jan 89 Feb 90 Jan 91 Sep-92I Oct-93
8-1 ND20S NA NA NA NA NA NA NA NA
8-2 ND20S 39 NA NA NA NA NA NA NA
8-3 ND20S NA NA NA NA NA NA NA NA
8 4 ND20S 39 NA NA NA NA NA NA NA
8-5 ND20S NA NA NA NA NA NA NA NA
8 8 NA NA NA NA NA NA NA 76 47.8
8-10 NA 19 NA NA NA NA NA NA NA
8-12 NA 18 NA NA NA 4.20* NA 24.5 25.7J
D8 12R NA NA NA NA NA 2.40* NA 200 17.2
EPA-1 NA 4.4* ND2.0 NA NA ND2.00 NA ND2.0 1.8
EPA-2 NA 2.3* ND2.0 NA NA NA NA NA 6.6
EPA-3 NA 2.8* ND2.0 NA NA ND2.00 NA 20.8 40
EPA-4 NA 3.3* ND2.0 NA NA NA NA 2.6 ND3.6
EPA-5 NA ND2.2 ND2.0 'NA NA 2.10* NA NA NA
F-10 NA NA NA ND2 NA NA NA NA NA
1-1 NA NA NA NA NA NA NA NA 307
1-7 NA NA NA NA NA NA NA NA 50.4
I 12 NA NA. NA ND2 NA NA NA NA NA
MW-3 NA NA NA ND2 NA NA NA NA NA
MW -12 NA NA NA NA NA NA NA NA 394
MW-39 NA NA NA NA NA NA NA 78.1 144
MW-42A NA NA NA NA NA NA ND7 23.3 7.7
MW-43D NA NA NA NA NA 3.10* NA 24.9 24.4
MW-44D NA NA NA NA NA ND2.00 NA NA NA
MW -47 NA NA NA NA NA NA NA 167 368
MW -48 NA NA NA NA NA NA NA ND2.0 66.2
MW -49 NA NA NA NA. NA NA NA 19.3 159
MW-57 NA NA NA NA NA 4.90* NA 64.5 3.5
MW-58 NA NA NA NA NA' NA NA 16.4J 182
MW-65 NA NA NA NA . NA ND2.00 NA 30.8 25.8
MW -66 NA NA NA NA NA 2.20* NA 7.7 67.0
P-1 NA NA NA NA ND50 NA NA NA 36.5
P-4R NA NA NA NA NA NA NA 51.2 75.7
P-6 NA NA NA NA NA NA NA 108 108
P-11 NA NA' NA NA NA NA NA NA 198
P-13 NA NA NA NA ,NA NA NA NA 90.4
P-14R . NA NA " NA NA NA NA NA NA 20.0
PZ92-04 NA NA NA NA NA NA NA NA 60.6
EST NA NA NA NA NA NA NA 21.1 29.9
RW-5 NA NA . NA NA NA NA NA 11.3 30.9J
NA = Not Analyzed
ND = Not Detected, number refers to detection limit
J = Estimated Concentration
S = Indicates spike recovery is within control limits
* = compound was detected but below the contract detection limit
-------
TABLE 5
WilLIAMS PIPE LINE 12TH STREET TERMINAL
BURN POND SUPERFUND SITE
Summary of Arsenic Detected in Filtered Groundwater
. During Phase I and Phase II RI
'Results in microarams/liter}
Monitor Well Phase ISep-92 Phase IIOct-93
B-8 ND2.0 ND1.0
B-12 2.5 .ND2.4
DB-12R ND2.0 3.6
EPA-1 ND2.0 . ND1.0
EPA-2 NA ND1.0
EPA-3 ND2.0 ND1.0
EPA-4 ND2.0 ND1.0
1-1 NA ND2.6
1-7 NA ND4.0
MW"":12 NA ND1.0
MW-39 ND2.0 ND1.0
MW-42R ND2.0 ND1.0
MW-43D 19.5 22.3
MW-47 ND2.0 ND1.0
MW-48 ND2.0 ND1.0
MW-49 ND2.0 ND1.0
MW-57 2.2 ND1.0
MW-58 ND2.0 ND1.0
MW-65 ND2.0 ND1.0
MW-66 ND2.0 ND1.0
P-1 . NA 7.5
P-4R 11.1 7.4
P-6 81.8 68.OJ
P-11 NA 114
P-13 NA 64.2
P -14R NA 15.6
PZ92-04 NA 45.7J
EST 21.5 27.OJ
RW-5 11 39.9J
J = Estimated Concentration
ND = Not Dectected; number following is the detection limit
NA = Not Analyzed
-------
Table 6
WILLIAMS PIPE LINE TERMINAL SUPERFUND SITE
Contaminants of Concern (COCs) for
Phase I and 11** Remedial Investigation .
Soil
VOCs:
2 - methylnaphthalene*
benzene
d ibenzofuran *
Sem ivolatiles:
acenaphthene
anthracene .
benzo (a) anthracene
benzo(a)pyrene
benzo(b )fluoranthene
benzo(g,h,i)perylene
benzo (k)fluoranthene'
chrysene
fluoranthene
fluorene .
indeno(1,2,3-ed)pyrene
phenanthrene
pyrene
Dioxins/Furans:
. Total HxCDD .
1234678-HpCDD
Total HpCDD .
Total TCDF
Total PeCDF
234678- HxCDF
Total HxCDF
1234678-HpCDF
Total HpCDF
OCDF
Metals:
arsenic
lead*
PCBs:
Aroclor-1254
Groundwater
VOCs:
.,1,17diC~loroethan~~/., .
.. .."t,J~tric:hlor()f}th~~t
..h:?~dibromoett1arie) ........
1 ,2-dichloro~ttlanE! . . .
t;2j3-"'tfich 10 ropr6Pi:irl~..
benzene
bromodichloromethane
ch loroform
......~~J~~~I~~IZJ9~.~~.~?~.......
Semivolatiles:
2- methylnaphthalene*
4:~ methylphenol*
~6~Qc}pbthene .......
dit:>~~*(jfciran* .
fll.JC)r~ije< '.. .... . ....
phenanthrene
Metals:
arsenic
* Qualitatively assessed in risk characterization
*~ Soils w~re addressed..()!1ly in Pha!;e..1 ..... ... .. . ... .... ..... , .... ...... . ........ .
-------
TABLE 7
CANCER RISK ESTIMATES
AVERAGE EXPOSURE REASONABLE MAXIMUM EXPOSURE
RECEPTOR PATHWAY CHEMICAL CHEMICAL- TOTAL PATHWAY RISK CHEMICAL- TOTAL PATHWAY
SPECIFIC SPECIFIC RISK
RISK RISK
Current or Ingestion of offsite Arsenic (total) 2E-04 1 E-03
future area groundwater 2E-04 1 E-03
resident
Future onsite Ingestion of onsite Phenanthrene 0 2E-04
resident (adult) groundwater
Benzene 3E-04 2E-03
Arsenic (total) 9E-05 6E-04
Arsenic (dissolved) 5E-05 4E-04
4E-04 (total As) 3E-03 (total As)
4E-04 (dissolved As) 3E-03 (dissolved
As)
Future onsite Inadvertent ingestion.
resident (child) of burn pond surface Benzo (a) anthracene 7E-05 1 E-04
soil
Benzo (b) fluoranthene 7E-05 1 E.04
Benzo (k) fluoranthene 7E-05 1 E-04
Indeno (1,2,3-cd) 6E-05 1 E-04
,pyrene
Banzo (a) pyrene 7E-04 1 E-04
Total PeCDF 2E-04 3E-04
Aroclor - 1254 1 E-04 2E-04
1 E-03 3E-03
Notes:
2E-04 = 2 X 10-4
PeCDF = total pentachlorodibenzofuran
Total As = used unfiltered groundwater samples that included total analytical arsenic levels.
-------
TABLE 8
CHRONIC NON-CANCER HAZARD QUOTIENT ESTIMATES
AVERAGE EXPOSURE REASONABLE MAXIMUM EXPOSURE
RECEPTOR PATHWAY CHEMICAL CHEMICAl- TOTAL PATHWAY HQ CHEMICAL- TOTAL PATHWAY HQ
SPECIFIC HO SPECIFIC HO
Current or Ingestion of Arsenic (total) 24 167
future area offsite Arsenic (dissolved) 0 24 (total As) 0 167 (total As)
resident groundwater g~gII~g:!~!9!M~~:Ili" m:~~:::::J.~!~igJ.MiI::e;il
Future onsite Ingestion of
resident (adult) on site Naphthalene 0.5 3.7
groundwater
Arsenic (total) 12.7 89.8
Arsenic (dissolved) 7.3 51.7
13.6 (total As) 94 (total As)
8.0 (dissolved As) 55 (dissolved As)
Future onsite Inadvertent Pyrene 0.2 0.4
resident (child) ingestion of burn Arsenic 5.3 10.7
pond surface 5.5 11.1
soil
Notes:
HQ = Hazard Quotient
Total As = used unfiltered groundwater samples that included total analytical arsenic levels.
Dissolved As = used filtered groundwater samples that included dissolved analytical arsenic levels. ,
-------
-------
10/18/94
17:22
141 002
(I:)
GRfAT FACES. GREAT PLACES.
DEPARTMENT of ENVIRONMENT
and NATURAL RESOURCES
JOE FOSS BUILDING
523 EAST CAPITOl
PIERRE. SOUTH DAKOTA 57501-3181
October 19, 1994
William P. Yellowtail, Regional Administrator
United States Environmental Protection Agency
Region VIII
999 18th Street - Suite 500
Denver, Colorado 80202-2466
Re:
Record of Decision
Williams Pipe Line Disposal Pit Superfund Site
Sioux Falls, Minnehaha County, South Dakota
Dear Mr. Yellowtail:
This letter serves as official notice that the state of South
Dakota, as represented by the Department of Environment and Natural
Resources, concurs with the U.S. Environmental Protection Agency's
Record of Decision concerning the Williams Pipe Line Disposal pit
Superfund Site. Under this Decision, the U. S. Environmental
Protection Agency has decided that no further action is necessary
at this Superfund site to protect human health and the environment.
A minimum of two years of quarterly groundwater monitoring will be
performed to verify that unacceptable exposure will not occur in
the future. This Decision concerns only .those contaminants
regulated under the Comprehensive Environmental. Response,
Compensation, and Liability Act of 1980, as amended by the
Superfund Amendments and Reauthorization Act of 1986.
Separate from this Decision is the ongoing assessment/
remediation of petroleum and nitrate contamination being performed
at the site under the state's authority.
. Sincerely,
Y\UL
f\~
Robert E. Roberts
Secretary
cy:
Tom Anderst, City Attorney's Office, Sioux Falls
-------
RESPONSIVENESS SUMMARY FOR
WilLIAMS PIPE LINE DISPOSAL PIT SUPERFUND SITE
RECORD OF DECISION
. September 1994
Environm.ental Protection. Agency
Region VIII
-------
RESPONSIVENESS SUMMARY FOR
WilLIAMS PIPE LINE DISPOSAL PIT SUPERFUND SITE
RECORD OF DECISION
This responsiveness summary provides an overview of public and the State of
South Dakota's (State) reaction to the preferred alternative; background on
community involvement; and summary of public comments and EPA's responses.
J.
OVERVIEW
The preferred alternative stated in the Proposed Plan for the Williams Pipe Line
Disposal Pit Superfund Site (Site) was "No Action with groundwater monitoring. II
The groundwater monitoring for 1 to 2 years was proposed to confirm that
groundwater contamination from arsenic is not escaping from the Williams Pipe
Line Terminal (Terminal) and presenting a potential drinking water risk. The
Proposed Plan clearly stated that the No Action alternative pertained only to the
Superfund work. It was assumed ongoing cleanup of groundwater petroleum
contamination would continue under State authorities. Petroleum is exempt from
regulation under the Superfund law.
The Proposed Plan was mailed to approximately 450 community residents, local
officials, and interested parties. The public comment period ran from July 28 to
August 27, 1994. No written comments were received.
A public meeting was held on August 16, 1994, at the Hayward Elementary
School in Sioux Falls, South Dakota. The meeting was attended by numerous
Williams Pipe Line Company representatives, several State employees, a county
commissioner, a city attorney, and several local residents. During the meeting two
citizens asked clarifying questions relating to the scope of the investigation and its
finc~ings.
. .
Also on August 16, 1994, the EPA project manager, State project manager, and
State hydrogeologist held a series of meetings with the staff of South Dakota
national senators and representatives, one State representative, and city officials.
The EPA project manager also met with one county commissioner on August 15th.
The meetings were to answer questions these officials might have prior to the
public meeting. Most of these people were unable to attend the public meeting.
The local officials appeared most concerned about continuing clean up of the
petroleum related groundwater contamination at the Terminal. They appeared
satisfied that the Proposed Plan stated that EPA's preferred alternative applied only
to the Superfund Site and the petroleum clean up was and would continue to be
handled under State authorities. The State also wanted to assure that Williams
Pipe Line as well as the public understood the scope of the preferred remedy
-------
II.
COMMUNITY INVOLVEMENT
More detail about past community involvement is provided in the Record of
Decision. Several fact sheets were issued to keep the community informed during
the Remedial Investigation (RI) process. In addition to the fact sheets issued'
during the RI, the Argus Leader newspaper published several articles that provided
updates on the RI.
Inquiries about the investigation from citizens have been'low to non-existent during.
the RI. This is in comparison to the considerable concern expressed by community
and local offcials when the Site was first discovered. Many of these early
concerns were addressed when Williams Pipe Line and the State took steps to
address the groundwater petroleum contamination that had spread beyond the
Terminal boundaries. .
III.
SUMMARY OF PUBLIC COMMENTS AND EPA RESPONSES
COMMENT/QUESTION: Mr. Nelson Vollink asked whether groundwater samples
were taken repeatedly farther away from the burn pond until no more
contamination was found.
RESPONSE: No, the sampling was not designed as such. However, the sampling
results did include a boundary of wells where no detection of contaminants was
found. It should be noted that the investigation centered on areas to the north,
east, and southeast of burn pond which is located in the eastern portion of the
Terminal. Groundwater was sampled during two RI phases. A larger number of
wells were sampled during the second phase. Dioxin and furans were only
analyzed for during the second phase.
In most cases, no contamination was detected in the groundwater monitoring wells
sampled outside the Terminal boundaries. The few exceptions are explained
. following.
.
In one well north of the burn bond and Terminal a very low amount of
2,4-08 herbicide was found. This did not appear to be associated
with the burn pond since several wells between the burn pond and the
well were void of contamination. The levels also were low enough
not to cause a health concern.
.
Low levels of dioxin and furan compounds were found in two wells
near the Terminal property. One well was located northeast of the
burn pond and one southeast of the burn pond. No contaminants
were found in a number of wells between each of these wells and
between the wells and burn pond. Therefore, it was concluded that
. the contamination was not associated with the burn pond. Again, the
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.
Total or unfiltered arsenic was found outside the Terminal boundaries.
As explained in the Proposed Plan and Record of Decision (ROD), it is
believed that no exposure to the total arsenic in groundwater is or will
occur. This is mainly because the arsenic in these samples appears to
be associated with sediment that was collected with the groundwater
sample. Dissolved or filtered arsenic was not found outside of the
Terminal boundaries.
..
Several contaminants associated with petroleum were found in wells
outside the Terminal property during the first phase of the RI.
Additional wells were sampled during the second RI phase and only
two contaminants associated with petroleum were found in one well .
southeast of the Terminal property. Again, a number of wells with no
detection of these contaminants were located between the well and
the burn pond. Petroleum is exempt from Superfund and the clean up .
of petroleum contamination is being addressed under State
authorities. .
COMMENT/QUESTION: Sue Brendon asked if there was any contamination found
in the wells northeast of the burn pond and Terminal property near the residences.
RESPONSE: No contamination was found in the ground water monitoring wells
during the RI in the area of the residences. .
Contamination, mainly pesticides, were found in several of these wells during the
listing investigation in 1987. Therefore, the ground water monitoring wells
northeast of the Terminal property were sampled in both phases of the Remedial
.Investigation (RI).
Additionally, there is a groundwater recovery well located north of the burn pond
which has influenced the direc.tion of the groundwater flow. Data shows that the
. groundwater near the burn pond is.being captured by the recovery well or .
groundwater interception trench located southeast of the burn pond. Groundwater
is currently not moving from the burn pond to the area of concern northeast of the
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