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PUBLIC HEALTH ASSESSMENT

HIGHWAY 71/72 REFINERY
BOSSIER CITY, BOSSIER PARISH, LOUISIANA


ENVIRONMENTAL CONTAMINATION

Contaminants have been detected in soil (surface and subsurface soil), indoor air, groundwater, and soil gas at the Highway 71/72 Refinery site. The primary contaminants are metals, polycyclic aromatic hydrocarbons, and volatile organic compounds. A description of the contaminants found in each medium are provided in this section.

In evaluating the environmental data, SEET considers many factors to determine if exposure to the contaminants at the site pose a public health risk. SEET selects and discusses contaminants based upon several factors:

  1. Field data quality, laboratory data quality, and sample design.

  2. Comparison of the on-site data with background concentrations.

  3. Comparison of on-site and off-site concentrations with environmental media comparison values for non-carcinogenic and carcinogenic endpoints.

Environmental media comparison values are used in order that the health assessor can determine which contaminants should be examined more closely for potential health effects. Several environmental media comparison values have been used in this review of the data. The environmental screening values used in this assessment include:

    RMEG---- ATSDR's Reference Media Evaluation Guide

    CREG---- ATSDR's Cancer Risk Evaluation Guide

    EMEG---- ATSDR's Environmental Media Evaluation Guide

    EPA SSL---- EPA's Soil Screening Level

    RFC ---- EPA's Reference Concentration

    LTHA----EPA's Lifetime Health Advisory for Drinking Water

Environmental screening values are media-specific comparison values which are used to select contaminants of concern at hazardous waste sites. The comparison value chosen for a chemical is lower than the levels expected to cause health effects in people. So even if a contaminant in a medium exceeds the comparison value, it does not necessarily mean that the contaminant is at a level that will produce health effects from exposure. Instead, if levels are above the environmental comparison value, the contaminant will be evaluated further in the health assessment. The contaminants detected in soil, soil gas, air, groundwater, and the tarry material are presented below.

A. Soil

In general, the soil in the southern portion of the site is more heavily contaminated with lead, arsenic, semi-volatile organic compounds (particularly, PAHs), and volatile hydrocarbons. The lead and arsenic appear to be most concentrated in the southwestern corner of the site in the vicinity of Alexis Park. However, there are some other areas of high metal concentrations scattered throughout the site.

Soil samples were collected from the site between June 18 and September 24, 1992 at the depths of 0-2 inches (surface soil), 2-12 inches (subsurface soil), and 12-24 inches (subsurface). A total of 105 samples were collected from each of these 3 depths, along with additional sampling, for a sum of 360 samples from 123 locations within and around the site (See Figure 4). Fifteen background samples from the three depths were taken from areas off-site which were considered not to be impacted by past activities on-site.

The site was divided into a grid containing 6 equal squares (A-F). Sections A-C were in the northern half of the site (north of Old Minden Road) and sections D-F were in the southern portion of the site (south of Old Minden Road). Samples were also taken from 11 residents' yards and from the tar-like substance at 3 locations (two single family homes and one from Alexis Park Apartments complex). See Table 11 in Appendix B for the test results of the tar-like substance. A total of 25 of the 360 soil samples were split (greater than 5%) for quality control assurance. An additional 15 confirmatory samples were obtained in November 1992 in 3 areas to evaluate the lateral extent ofmetal contamination. All three areas were in the southern-most part of the site.

Surface Soil
Inorganic Contaminants

Lead, arsenic, and mercury have been detected in surface soil (0-2 inches). See Table 1 for the concentrations of inorganic contaminants. Lead was found in all 105 surface soil samples collected. The lead concentrations in soil ranged from 5.8-3130 ppm. The average lead concentration was 193 ppm. The average lead concentration taken from background samples was 50.4 ppm. Several 0-2 inch soil samples in Alexis Park playground and volleyball court were near or above 1000 ppm. The highest playground soil lead concentration was 978 ppm. Confirmatory sampling demonstrated that lead contamination extended outward from the volleyball court and showed lead levels at 2,930 ppm, 3,090 ppm, 748 ppm, and 1,510 ppm. The area of highest lead contamination was found at the volleyball court which was the location of the former processing area for petroleum product manufacturing at the site.

Arsenic is a naturally occurring metal in soil occurring in background samples at an average concentration of 5 ppm. The average arsenic level on-site was 4.2 ppm, which is approximately equal to the background level. Arsenic was present in all the surface soil samples. The arsenic concentration ranged from 0.7-47.8 ppm in the top 0-2 inches of soil. The highest arsenic levels were found south of Old Minden Road in the old processing area. The maximum and average arsenic concentrations reported were above comparison values. The maximum arsenic level in the confirmatory samples was 5.6 ppm

Mercury was found in approximately 10% of the samples. The mercury concentrations in surface soil ranged from 0.11-2.1 ppm. Mercury was not detected in the background samples. Mercury was analyzed for in only two confirmatory samples and was not found above the detection limit (0.10 ppm).


Table 1.

Metal Contaminants in 0-2 Inch Soil Samples (1).
Inorganic
Contaminant
Frequencyof DetectsConcentrationRange (ppm) Average
(ppm)
Comparison Value (CV) in ppm.
Above CV? (yes/no)
Arsenic117/1170.7-47.84.16 0.5 (CREG)
yes
Lead134/1345.8-3130193 400 (EPA SSL)
yes
Mercury 17/1050.11-2.10.084 none
ppm = parts per million

Organic Contaminants

A number of polycyclic aromatic hydrocarbon (PAHs) compounds were detected in the surface soil. The PAHs detected in 25% or more of the soil samples are recorded in Table 2. Both the maximum and average levels of benzo(a)pyrene exceeded environmental comparison values in the 0-2 inches soil samples. The maximum levels for benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)anthracene, and indeno(1,2,3-cd)pyrene were above their comparison values.


Table 2.

Semivolatile Organics Detected in 0-2 Inches Soil Samples (1)
Polycyclic AromaticHydrocarbonsFrequencyof DetectsConcentration
Range (ppm)
Average
(ppm)
Comparison
Value (CV) in ppm.
Above CV? (yes/no)
Anthracene24/1050.041-1.80.134600 (RMEG)
no
Benzo(a)anthracene47/1050.041-6.00.2570.9 (EPA SSL)
yes
Benzo(a)pyrene42/1050.038-5.60.2510.1 (CREG)
yes
Benzo(b)fluoranthene65/1050.035-160.4910.9 (EPA SSL)
yes
Benzo(g,h,i)perylene 32/1050.043-2.50.226none
Benzo(k)fluoranthene62/1050.035-160.4939 (EPA SSL)
yes
Chrysene66/1050.036-6.40.30788 (EPA SSL)
no
Fluoranthene60/1050.037-9.20.32380 (EPA SSL)
no
Indeno(1,2,3 cd) pyrene22/1050.04-2.50.1940.9 (EPA SSL)
yes
Phenanthrene 64/1050.045-5.60.337none
Naphthalene32/1050.042-1.30.1483100 (EPA SSL)
no
2-methyl naphthalene 47/1050.045-2.80.275none
Benzo(a)pyrene Equivalents66/1050.054-9.770.4 10.0 (EPA SSL)
no

Subsurface Soil (Greater Than 2 Inches Deep)
Inorganic Contaminants

Lead was present in all 105 samples collected. The range of lead concentrations was 3.6 -1570 ppm. The average lead concentration was 148 ppm. The background lead concentration at 2-12 inches was 32 ppm. See Table 3 for results.

Arsenic was detected in all 105 samples taken at 2-12 inches at concentrations ranging from 0.98 -18.0 ppm. The average arsenic at 2-12 inches was 4.4 ppm. The background concentration for arsenic at this depth was 4.6 ppm. The maximum arsenic concentration exceeded the environmental comparison value.

Mercury was detected less frequently than arsenic or lead in the subsurface soil. The mercury concentration in the soil ranged from 0.11 ppm - 6.4 ppm. The background level of mercury was 0.06 ppm. The average concentration was 0.25 ppm.


Table 3.

Metal Contaminants in Subsurface Soil (2-12 inches) Samples (1).
ContaminantFrequencyof DetectsConcentrationRange (ppm)Average
(ppm)
Comparison Value(CV) in ppm
Above CV? (yes/no)
Arsenic105/1050.98-18 4.42 0.5 (CREG)
yes
Lead109/1093.6-1570 148400 (EPA SSL)
yes
Mercury 27/1050.11-6.4 0.256 none


Organic Contaminants

Table 4 indicates that a number of semi-volatiles compounds were detected in the subsurface soil. Benzo(a)pyrene levels exceeded the environmental comparison value. The average benzo(a)pyrene [B(a)P] equivalent was 1.46 ppm with a maximum value of 3.75 ppm compared to the average and maximum values for the 0-2 inches soil which were 0.4 ppm and 9.77 ppm, respectively.


Table 4.

Semi-Volatile Organics Detected in Subsurface Soil (2-12 inches) Samples.
ContaminantNumber ofSamplesConcentrationRange (ppm)Average
(ppm)
Comparison Value
(CV) in ppm.
Above CV? (yes/no)
Anthracene39/1050.037-1.00.132600 (RMEG)
no
Benzo(a)anthracene51/1050.04-1.90.208none
Benzo(a)pyrene45/1050.043-1.60.1880.1 (CREG)
yes
Benzo(b)fluoranthene52/1050.041-4.50.2590.9 (EPA SSL)
yes
Benzo(g,h,i)perylene 36/1050.048-1.50.240none
Benzo(k)fluoranthene50/1050.041-4.50.2639 (EPA SSL)
no
Chrysene54/1050.049-3.90.28888 (EPA SSL)
no
Di-n-butylphthalate 5/1050.038-0.750.217none
Dibenzo(a,h)anthracene 6/1050.047-0.180.226none
Fluoranthene48/1050.043-2.50.186 80 (EPA SSL)
no
Indeno(1,2,3 cd) pyrene26/1050.043-0.770.1300.9 (EPA SSL)
no
Naphthalene43/1050.037-4.20.2773100 (EPA SSL)
no
2-methylnapthalene 53/1050.043-180.607none
Phenanthrene56/1050.043-100.527none
Pyrene58/1050.046-5.20.387none
Acenaphthene13/1050.038-0.620.089 100 (RMEG)
no
Fluorene19/1050.037-0.540.099 80 (RMEG)
no
Benzo(a)pyrene
equivalents
58/1050.296-3.751.4610.0 (EPA SSL)
no

Total Volatile Organic Compounds in Soil

Soil (0-24 inches)

The total volatile organic compounds (VOCs) concentrations in soil gas were screened at the three soil depths using a flame ionization detector (FID). At each sampling location, three soil samples were collected from one borehole (0-2, 2-12, and 12-24 inch depth intervals) for laboratory analyses. Borings were advanced to the specified depths and at each depth total volatile organic compounds (VOCs) concentrations were measured in the borehole using a flame ionization detector (FID). Five samples had total VOC concentrations above approximately 1000 ppm at one or more of the three depth intervals (0-2, 2-12, and 12-24 inches). The highest concentration was greater than approximately 10,000 ppm and was found in a sample taken near the United Methodist Church. A sample taken from the Alexis Park Apartment complex and one from a single family home adjacent to Alexis Park had concentrations of VOCs at approximately 4,000 ppm and 1,500 ppm, respectively.

Two screening samples of soil gas taken from the northern portion of the site, one from soil (approximately 4,000 ppm) and the other from a tar-like material on the ground surface (approximately 1,850 ppm), also had elevated VOC levels. The level of VOCs was not screened in the other two tar samples which were taken from the soil surrounding a single family home and from the Alexis Park Apartment complex.

Soil (2 -7 feet)

A soil gas analysis was also conducted at greater depths on the site from June-September 1992. The investigation was conducted to determine the presence of site contaminants (hydrocarbons) in the soil. A complete description of the survey is included in Appendix B, Table 10. Methane, benzene, ethylbenzene, toluene, and xylene were detected in soil gas in depths up to 7 feet. Methane was detected in a range of 556 ppm-719,753 ppm. The maximum concentrations the BTEX compounds were as follows: benzene (196 ppm), ethyl benzene (31 ppm), toluene (103 ppm) and xylene (50 ppm). As with indoor air, the analysis was for methane and BTEX compounds only.

B. Air

Investigations have been conducted to identify contaminants in indoor air and soil gas at the Highway 71/72 Refinery site. A complete data review of the available air data through 1996, has been conducted and is provided in Appendix B of this public health assessment. This review was conducted to determine if there is adequate data to assess the public health impact of indoor air and soil gas contaminants at the Highway 71/72 Refinery site.

Based on the available data reviewed, it was concluded that there are data gaps which limit the ability for SEET and ATSDR to make a conclusive health evaluation of the indoor air contamination. The limitations of the data are:

  1. Some contaminants such as sulfur compounds and vinyl chloride commonly found with oiland refinery operations that could be of health concern were not consistently analyzed for in soil gas, groundwater, or indoor air.

  2. The source of the odor complaints beginning in the mid 1980's has not been identified.

  3. The detection limits of some instruments used to analyze for certain contaminants were higher than the levels that are of health concern. Therefore, we cannot determine if exposure is occurring at levels of health concern.

  4. The duration of some sampling events was often short (minutes to a few hours) and may not be representative of actual conditions to allow an adequate health evaluation.

  5. Sampling frequency was low and not continuous.

  6. Weekly or monthly indoor monitoring of methane that was conducted might not berepresentative of the daily fluxes in methane concentration.

  7. Holding times on some indoor air samples (prior to analysis) were too long.

In spite of the limits of the data, there are some samples that suggest a problem may exist. Benzene levels found in some of the indoor air samples from 1990-1994, if representative of long term exposures, may pose a health risk to residents. Benzene has been detected in a number of indoor air samples of residences and hotels (See Table 5). The indoor benzene concentrations range from non-detect to levels as high as 223.7 ppb in apartments on the Highway 71/72 Refinery site. Indoor air samples have been collected for short durations and infrequently. Therefore, it is not possible todetermine if these benzene levels are representative of concentrations over time. It is not known whether the source of the benzene is site related. Soil gas sampling was not conducted concurrently with the indoor air measurements.


Table 5.

Benzene Concentrations Reported In Residential Properties
Sampling Location Range of Benzene Concentrations Reported
(ppb)
Sampling
Date
Comparison Value (C.V.) in ppb.
C.V. Exceeded? yes/no
Residence Inn
(Units 311, 314)
10-80 7/90 0.03 (CREG)
yes
Alexis Park Apts. (Unit 1905) 2-110 7/90 0.03 (CREG)
yes
Alexis Park Apts.(Units 911, *501, 505, 1307) 2-223.7 11/93 0.03 (CREG)
yes
Carriage Square
Apts.
22.5-160.0 11/93 0.03 (CREG)
yes
Carriage Square
Days Inn
Motel 6
LaQuinta
Sheraton
Residence Inn
Plaza Circle
2.1-26.0 5/94 0.03 (CREG)
yes
ppb = parts per billion, (1 ppm = 1000 ppb)
* The maximum benzene concentration of 224 ppb was found in apt. 501.

In 1990, methane (maximum concentrations of 230,000 ppm and 160,000 ppm) was detected in the subsurface soil 5 feet under Alexis Park apartment building 5 (See Table 6). Methane concentrations equal to or above 53,000 ppm may present an explosion hazard.

Methane has been detected inside cabinets, under sinks, in walls, and in the breathing zone (4.5-5.5 feet from the surface of the floor) of some of the Alexis Park Apartments (See Table 7). The highest readings detected were in Apt. 501 of the Alexis Park Apartments. The maximum methane level in apartment 501 was 4147 ppm in 1990. Total hydrocarbon levels in building 5 were 10,000 ppm in 1990 and 6,000 ppm in 1993. As a precautionary measure residents were evacuated from apartments in building 5 of Alexis Park Apartments. Building 5 remains closed for occupancy under advice of OPH/SEET. The source of methane or the factors that may affect the fluxes in indoor air concentrations has not been clearly defined.

Soil gas contains other compounds besides methane. The testing of the VOC vapors in soil gas on-site reveals that these vapors consists primarily of 90-96% methane. The remaining hydrocarbons in the soil gas vapor could be of potential health concern.


Table 6.

Methane Concentrations Under Cement of Building 5 of Alexis Park
Sampling Location Range of Methane Concentrations (ppm) Date of Sampling
Apt. 505 176,000 - 230,000 2/5/90
Apt. 505 140,000 - 160,000 2/5/90
Apt. 501 30,000 - 37,000 2/5/90
Apt. 501 40, 000 - 44,000 2/5/90


Table 7.

Methane and Total Hydrocarbons Concentrations Reported In Residential and Commercial Properties
Sampling Location Range of Methane Concentrations
Reported*
(ppm)
Range of Total Hydrocarbons concentrations** (ppm) Date of Sample
Collection
Alexis Park
Unit 1905
Tedlar 2348 FID nd-1500
FID 6-200
6/90
7/93
7/90
Alexis Park
Unit 1309
Tedlar 1355 FID 3-8000
FID 21-120
1/90
8/93
2/90
Alexis Park
Unit 501
Tedlar 4147 FID 10-10 000
FID 30-6000
2/90
7/93
2/94
Alexis Park
Unit 503
Tedlar 421 FID 4-3000
FID 32-1250
1/90
7/93
3/91
Alexis Park
Unit 505
Tedlar 2354 FID 16-7000
FID 22-800
1/90
8/93
2/90
Alexis Park
Unit 307
Tedlar-none FID nd-16
FID 0-50
5/90
7/93
Kutz Accounting
215 Bobbie St.
Tedlar none FID 12-5000 7/93
*Tedlar bag sampling was used to measure specific hydrocarbons such as methane.
**FID- Flame Ionization Detection measures total hydrocarbons and provides initial screening samples.
nd- non-detected

Other volatile organic compounds, besides benzene, have been detected in indoor air in the breathing zone. Ethylbenzene, toluene, xylene, and styrene have been detected in indoor air samples. However, none exceeded comparison values. The range of concentrations reported are included in Table 8.


Table 8.

Volatile Organic Compounds Detected in Indoor Air
Contaminant Concentration Range
(ppb)
Comparison Values (ppb) Exceeded? yes/no
ethylbenzene 0.33-34.8 300 EMEG / no
toluene 2.11-170.6 1000 EMEG / no
xylene 1.59-79.5 40 EMEG / yes
styrene 0.18-32 200 RFC / no

C. Tar-like Material

An oily black tar-like substance has been reported on the site since 1985. This substance is most likely the remaining residue from oil refinery processes. Tar samples have been collected from the access road to the Bossier Crossroads Shopping Center; which was the old process and waste disposal area; at a home at Carriage Square; and at Alexis Park. Grab and composite samples have been collected and analyzed. However, the results are questionable because too few sample were taken, the paperwork guaranteeing the integrity of sample as it changed hands (chain of custody) was often missing, and the lab procedures used to evaluate the accuracy of testing rated poorly (quality control and assurance). The analysis of the tarry material indicates the presence of polycyclic aromatic hydrocarbons, volatile organic compounds, and metals (See Table 11, Appendix B). This data is not useable to estimate the exposures individuals might encounter but provides some indication of the materials that should be further investigated for their presence in indoor air and soil gas.

The analysis done on 3 tar samples taken during the surface soil investigation in 1992, show 2 of the samples have high levels of PAHs. However, analysis of metals was not done on any of the samples and screening for total volatile organic compounds using a FID was only done on one sample. (See Table 12, Appendix B)

D. Groundwater

Groundwater was sampled by drilling hollow stem augers 7-10 inches in diameter into the ground at a depth of 27-53 feet below the ground surface. Forty samples were collected, including 2 duplicates.

The groundwater beneath the site contains hydrocarbons including polycyclic aromatichydrocarbons and volatile organic compounds which may be contributing to soil gas and indoor air contamination (2). Testing of the monitoring wells west of John Wesley Blvd, near Motel 6 and Day's Inn, showed the groundwater to be heavily contaminated with PAHs. Levels of BTEX contaminants were elevated in monitoring well samples from Motel 6 and Alexis Park Apartment complex areas. See Table 9 for sampling results.

The groundwater underneath the site is not used as a water source for residents on or off-site. There is one private well on-site but this well is closed. The residents of Bossier City, including those living on site, are serviced by public water supply which is obtained from the Red River, up gradient of the site. Monitoring wells placed between the site and the Red River have not demonstrated groundwater contamination. The contaminated groundwater plume is estimated to move towards the river at a rate of less than 1 inch per year. A partial review of Bossier City Water System analysis records for 1992 and 1993 indicated that concentrations for volatile organic compounds, pesticides, and metals were either non-detectable or were present below Federal and State Drinking Water Quality Regulations.


Table 9.

Groundwater Sampling November, 1992. From Deep Boring and Groundwater Sampling Results, Volume II, Remedial Investigation, Former Arkansas Fuel Oil Refinery Site, June 7, 1995*
Compound Frequency of Detects Range of Concentrations (ppm) Comparison Value
(ppm)
Exceedence Yes/No
benzene 20/51 nd-49 0.001 CREG / yes
toluene 32/51 nd-2.7 0.2 EMEG / yes
ethylbenzene 13/51 nd-1.1 0.7 LTHA / yes
xylene (total) 14/51 nd-4.2 2.0 EMEG / yes
naphthalene 16/39 nd-1.6 0.02 LHTA / yes
2-methylnaphthalene 15/39 nd-4.2 none
fluorene 5/39 nd-0.24 0.4 RMEG / no
phenanthrene 4/39 nd-0.31 none
di-n-butylphthalate 7/39 nd-0.016 6.0 EMEG / no
acenaphthene 2/39 nd-0.023 0.6 RMEG / no
anthracene 1/39 nd-0.1 3.0 CREG / no
pyrene 0/39 nd 0.3 RMEG / no
phenol 09/39 nd-0.37 6.0 RMEG / no
arsenic 17/39 nd-2.19 0.00002 CREG / yes
chromium 35/39 nd-0.244 0.003 CREG / yes
lead 22/39 nd-0.15 0 MCLG / yes
mercury 2/39 nd-0.00026 none
cyanide 0/39 nd 0.2 RMEG / no
* The detection limit for volatiles and semi-volatiles was 0.01 ppm. Detection limits for inorganics ranged from a low of 0.0002 ppm for mercury to a high of 0.01 for chromium.


PATHWAYS ANALYSIS

In order to determine whether nearby residents are exposed to contaminants, SEET evaluates the environmental and human components that lead to exposure (pathways of exposure). A pathway of exposure consists of five elements: a source of contamination, transport of that contaminant in a medium (such as soil, water, and air), a point of exposure, a route of exposure (ingestion, skin contact, and/or inhalation), and an exposed population.

Pathways of exposure are categorized as completed, potential, or eliminated. A completed exposure pathway is indicated by all five elements of a pathway being present. Even though a completed pathway exists, it doesn't mean the levels of a chemical the person is exposed to are high enough to cause health effects.

A potential pathway is a pathway in which one element of the five elements is missing, but could exist. A pathway can be eliminated if one element of a pathway is missing and will never be present. Exposure pathways can exist in the past, present, and future. Information on the pathways of exposure for the Highway 71/72 Refinery site are presented in the following sections.

A. Completed Pathways of Exposure (See Table 10)

Surface Soil

Metals and polycyclic aromatic hydrocarbons have been detected in surface soil. Residents (adults and children), on-site visitors, and workers could come in contact with contaminants in the surface soil by skin contact or incidental ingestion of the soil. These individuals may be exposed to site contaminants during activities such as work or play.

Tar Material

A tarry material has seeped to the soil surface in areas of the old impoundments on the site. The material has also been found several feet underground during on-site construction. The tar material has been reported in residential areas, apartment complexes, and hotel parking lots. Residents (adults and children), visitors, and workers could be exposed to contaminants in the tar material from skin contact or ingestion.

Air

Volatile organic compounds, especially benzene, have been detected in the indoor air of homes and apartments. The source of the indoor air contamination has not been determined. Residents are exposed to contaminants in the air by inhalation.

The concentration of methane in several samples taken 5 feet underneath building 5 in Alexis Park show elevated levels of methane (maximum concentration of 230,000 ppm) which most likely is the source of methane found in indoor air. Levels of methane above its lower explosion limit of 53,000 ppm could pose an explosion hazard. Methane has been detected in the walls and living space of the Alexis Park Apartments. The highest methane levels were detected in Apt. 501 in Alexis Park Apartments during 1990 and 1993 at levels of 10,000 ppm and 6000 ppm, respectively. Building 5 of Alexis Park Apartments is no longer leased as a precautionary measure.

B. Potential Pathways of Exposure (See Table 11)

Subsurface Soil

Metals and semi-volatile organics have been detected in the subsurface soil. Workers or residents could come in contact with contaminants in the subsurface soil by excavation of the soil and during activities such as digging ditches for utilities, or gardening in on-site yards.

Soil Gas

Volatile organic compounds have been detected in soil gas samples. The soil vapor constituents have been detected in indoor air samples and may be contributing to the indoor air contamination. Residents could inhale soil gas contaminants that migrate into indoor air.

C. Eliminated Pathways of Exposure (See Table 12)

Residents living on the site obtain their drinking water from a public water supply furnished by the Red River up gradient from the site. The few private wells known to exist within Bossier City are not used for drinking water purposes. Future use of the groundwater is unlikely since a City ordinance requires that all buildings within 300 feet of an existing water line be connected to the public water supply. Because of the density of development in the area of the site, new buildings would be located in 300 feet of the public water supply.


Table 1.

Completed Exposure Pathways
Pathway Source Environmental Media Point of Exposure Route of Exposure Exposed
Population
Time
surface soil Hwy 71/72
Refinery
site
surface soil residential yards

commercial properties
ingestion

dermal contact

residents
workers
visitors
past
present
future
tarry material Hwy
71/72
Refinery
site
tarry
material
residential
yards

commercial
properties

ingestion

dermal
contact

residents
workers
visitors
past
present
future
air unknown air indoor air

ambient air

inhalation residents
workers
past
present
future
methane unknown air residences

businesses

not applicable residents
workers
past
present
future


Table 11.

Potential Exposure Pathways
Pathway Source Environmental Media Point of Exposure Route of Exposure Exposed
Population
Time
subsurface soil Hwy 71/72
Refinery
site
subsurface soil residential yards

commercial properties

ingestion
dermal contact
residents
workers
past
present
future
soil gas Hwy 71/72
Refinery
site
soil gas residential yards

commercial properties

inhalation residents
workers
visitors
past
present
future


Table 12.

Eliminated Exposure Pathways
Pathway Source Environmental Media Point of Exposure Route of Exposure Exposed Population Time
groundwater Hwy 71/72
Refinery
site
groundwater residences

commercial properties

ingestion
dermal
contact
residents
workers
visitors
past
present
future


PUBLIC HEALTH IMPLICATIONS

A. Toxicological Evaluation

In this section we will discuss the health effects, if any, that might occur in persons exposed to specific contaminants at the site. There were three types of chemicals that were identified at the site including metals, semivolatile organics, and volatile organics that exceeded environmental comparison values in soil and air. A discussion on the health implications of exposure to these chemicals is provided for each class of these compounds. Because people live on-site, health effects were evaluated based on a daily, residential exposure over a life- time (70 years). Young children's play habits often bring them into contact with surface soil and its contaminants. Children's developing bodies also make them more sensitive to many contaminants. When evaluating health effects from surface soil contaminants, young children (6 months to 6 years) were chosen as the most sensitive group.

Arsenic

Arsenic occurs naturally in surface soils in concentrations of 5 ppm. The highest arsenic concentration reported in surface soil at the site was 47.5 ppm. There was only one sample value reported at this concentration. The next highest arsenic concentration reported in soil was 18 ppm.

At the levels reported, children or adults should not experience adverse health effects (noncancer or cancer) from incidental ingestion of the soil. Absorption of arsenic in soil through the skin would be minimal and would not be expected to produce health effects.

Lead

Lead has been detected from 5.8 to 3,130 ppm in surface soil at 0-2 inches which is the soil layer people have the greatest contact with. Exposure to lead is of health concern since lead has been shown to effect many organs in the body. The most sensitive organs to the toxic effects of lead are the nervous system (particularly in children), the blood system, and the cardiovascular system. Children are more sensitive to the toxic effects of lead because they absorb more lead than adults from their digestive tract. Children are often exposed to lead in the soil because they play in dirt andput their fingers in their mouths. Children with elevated blood lead may have impaired learning, be restless, and experience nausea and stomach cramps.

A blood lead test can help determine if a child has been exposed to lead. Lead remains circulating in the blood several weeks after exposure and then redistributes into other organs including bones, liver, and kidney. The Center for Disease Control and Prevention (CDC) in Atlanta, Georgia, currently considers a blood lead level in children below 10 micrograms (ug) of lead per deciliter (dL) of blood to be a concentration that is not indicative of lead poisoning. In order, for LOPH to assess if lead exposure had been occurring, children living on-site were tested in July 1995.

The children who were tested all had blood leads below 10 ug/dL. However, the children tested were only a portion (55 out of approximately 300 children) of all the children between ages 6 months and 6 years who currently live on-site. They were not necessarily representative of the larger population of children who were eligible for testing. Some areas with high lead levels are still accessible to young children. If the soil becomes exposed by the loss of the grass cover, children could be exposed to lead at levels of health concern.

Mercury

Mercury is an element that occurs naturally in the environment. The highest level reported in the soil was 2.1 ppm in the surface soil. It is not expected that health effects would be produced from incidental ingestion or skin contact with the soil in children or adults at the reported mercury concentrations.

Semi-Volatile Organics

The semi-volatile compounds identified in the soil are polycyclic aromatic hydrocarbons (PAHs). PAHs are formed during the incomplete burning of organic material such as fossil fuels and wood. They are a group of compounds with varying degrees of toxicity. The class of compounds called polycyclic aromatic hydrocarbons (PAHs) are comprised of many chemicals with varying degrees of toxicity. To describe the cumulative effect of PAHs on human health, benzo(a)pyrene was chosen as a reference compound to which the cancer effects of other PAHs would be compared. Benzo(a)pyrene was assigned a toxicity factor of 1 and the other PAHs are given a toxicity valuebased on their comparative toxicity to benzo(a)pyrene. The toxicity factors are multiplied by the concentration of the PAH compound and then all the products are summed to produce a benzo(a)pyrene equivalent which is abbreviated as: B(a)P equivalents. The B(a)P equivalent value was used to estimate the risk of cancer from PAHs in the soil.

Benzo(a)pyrene

Benzo(a)pyrene can be found in a number of environmental sources including tobacco smoke and cooked food. Benzo(a)pyrene has been detected in urban soils in a range of 0.165-0.220 ppm. Benzo(a)pyrene has been detected in certain cooked foods in values as great as 60 ppm. This level exceeds the soil value seen at the site.

Based on the benzo(a)pyrene levels reported in the soil, no adverse health effects are expected to occur from ingestion of or skin contact with the soil. Benzo(a)pyrene has been shown to produce cancer in laboratory animals when applied on their skin. At the levels reported, there is no increased risk for cancer for residents based on exposure to benzo(a)pyrene.

Benzo(a)anthracene

Individuals can be exposed to benzo(a)anthracene from contaminants in the soil as well as sources such as tobacco smoke and cooked food. Benzo(a)anthracene has been detected in urban soils at levels in a range of 0.169-5.9 ppm. The level reported in soil on-site is slightly higher than the range normally reported in urban soils.

Benzo(a)anthracene has been shown to produce cancer in animals when applied to the skin. At the benzo(a)anthracene levels in on-site surface soil, no adverse health effects are expected to occur (noncarcinogenic or carcinogenic).

Volatile Organic Compounds

Benzene

Non-cancerous health effects that occur suddenly such as dizziness, nausea, and headaches are not expected to be produced from inhalation of the maximum benzene concentrations (<1 ppm) found in the breathing zone. In several animal studies, laboratory animals inhaling 10 ppm for 5-15 days demonstrated no physical changes.

However, studies investigating the non-carcinogenic effects of chronic (greater than one year) exposure to low levels of benzene such as the levels reported in on-site indoor air (maximum concentration 0.224 ppm) are scarce. The few studies that were available for review showed no health effects on laboratory animals. Therefore, the non-cancerous health effects of chronic exposure to benzene levels which are less than 1 ppm is not known.

Benzene is a known human carcinogen. The cancer it produces with the highest frequency is leukemia. Studies reviewing workers' occupational exposures to benzene in air at 100 ppm or greater for 2 or more years have an increased incidence of leukemia. Animal studies also show long term exposure to 100 ppm to 300 ppm produces cancer. There were several maximum benzene levels between 0.1 ppm and 0.2 ppm. If residents were exposed to these maximum benzene levels daily, their risk for cancer would increase to an unacceptable risk level.

Xylene

The maximum level of xylene found in indoor air samples was 37.4 parts per billion (ppb). This level is well below the levels associated with non-cancer health effects. The cancer risk associated with xylene is not known.

Toluene

The maximum level of toluene reported in the air was 170.6 ppb. This is below levels that are reported to produce health effects in humans. Much higher levels of exposure are associated with health effects in humans. The reports from occupational and animal studies do not suggest that toluene is carcinogenic.

Ethylbenzene

Based on the highest indoor air levels reported in the 1994sampling (0.011 ppm), noncancer health effects are not expected to occur from inhalation exposure. No association has been found between ethylbenzene exposure and cancer. Only one study was located that monitored workers chronically exposed to ethylbenzene. No case of cancer in these workers were reported during the 10 years they were monitored.

B. Child Health Initiative

ATSDR's Child Health Initiative recognizes that the unique vulnerabilities of infants and children demand special emphasis in communities faced with contamination of their water, soil, air, or food. Children are at greater risk than adults from certain kinds of exposures to hazardous substances emitted from waste sites and emergency events. They are more likely to be exposed because they play outdoors and they often bring food into contaminated areas. They are shorter than adults, which means they breathe dust, soil, and heavy vapors close to the ground. Children are also smaller, resulting in higher doses of chemical exposure per body weight. The developing body systems of children can sustain permanent damage if toxic exposures occur during critical growth stages. Most importantly, children depend completely on adults for risk identification and management decisions, housing decision, and access to medical care.

The likelihood of children living in the vicinity of the Highway 71/72 site to be exposed to site contaminants at levels of health concern was assessed. Lead was identified as a likely exposure. Lead in soils is at a level of health risk to children, however, based on limited blood lead sampling, there is no evidence that children possess blood lead levels at cause for concern. However, if children were to frequently play on the contaminated soils, they could be at risk.

C. Health Outcome Data

From July 10 - July 22, 1995, representatives from SEET and ATSDR conducted a door-to-door survey and blood lead screening of children 6 months to 6 years. The survey consisted of the distribution of OPH/SEET pamphlets on lead poisoning and completion of a health survey for households with young children. One-hundred-and-fifty-two (152) appointments were scheduled for blood lead testing of children.

Seventy-five (75) children voluntarily attended the testing, and 68 children had their blood drawn successfully. Of these 68 children, 55 (the target group) met the investigation criteria of living on-site and being between 6 months and 6 years old. The average blood lead concentration for these 55 samples was 2.9 ug/dL. The range was 0 - 9 ug/dL. The median was 3 ug/dL and the most frequent value was 2 ug/dL. See Table 13 for results. There were 4 blood lead concentrations at 0 ug/dL. None of the children tested were above the level (10 ug/dL) requiring medical intervention.


Table 13.

Results of Lead Exposure Investigation, July 1995.
number of samples range
(ug/dL)
average (ug/dL) median (middle value)
(ug/dL)
mode (most frequent value)
(ug/dL)
55 0-9.4 2.9 3 2

The target group of 55 children had an average age of 3 years and an average on-site residence time of 15 months. In this target group, 13% of the children lived in homes, and 87% lived in apartments (36% in Park Place Apartments, 34% in Alexis Park Apartments, 15% in Port Au Prince Apartments, and 2% at St. Charles Place Apartments).

D. Community Health Concerns

Community health concerns were collected from citizens during public meetings and during a door-to-door survey prior to the blood lead survey and testing done by OPH/SEET and ATSDR. The following health related concerns were raised by city officials and site residents:

  1. Residents were concerned that their children would be exposed to lead from playing in their yards and common areas of the apartment complexes.


  2. An exposure investigation was conducted in July 1995 to determine the blood concentrations of lead in children living on the site. The results indicated that none of the children tested had blood lead levels above 10 ug/dL. This data indicated that the children tested were not being exposed to lead at concentrations that are indicative of lead poisoning. Children who lived in the apartment complexes were included in the testing. We are not sure if the children tested, played on the areas where lead contamination was elevated. A grass cover exists over most of these areas, which limit a child's contact with contaminated soil. Measures as simple as having the child wash his or her hands after outside play, and prior to eating, can reduce the chances of lead exposure.

  3. Residents were concerned that lead exposure increased their risk of cancer.


  4. Lead exposure has been associated with cancer in animals, but no evidence for lead causing cancer in humans has been found.

  5. Parents wanted to know how they could tell if their child had been exposed to lead.


  6. The best way to determine if a child has been lead exposed is to obtain a blood sample from the child and have the sample analyzed for lead. Children 6 years old and younger are most at risk for lead poisoning.

  7. Residents are concerned that they need to move because of contamination on-site.


  8. Though the site has elevated lead and arsenic concentrations in some locations, most areas are covered by grass or asphalt, which reduces contact between contaminants and people. High levels of methane and benzene in indoor air have been recorded in some residences which caused the evacuation of 47 families from Alexis Park and the closing of one buildings in the Alexis Park Apartment complex. This building is still closed as a precautionary measure.

    The methane gas readings during 1990 were much higher than levels recorded in 1992 and1993. The source of these gases has not been determined and therefore we do not know ifthe problem has been alleviated. However, benzene levels have been elevated duringseveral indoor air sampling episodes between 1990-1994. SEET and ATSDR arerecommending further indoor air sampling to determine if the indoor air contamination poses a threat to residents. The past indoor air sampling was short-term and did not analyze for a large enough scope of contaminants. Therefore, we do not know if they are representative of the general air quality of the homes and apartments on the site. The source of the indoor air contamination is not known but may be from soil gas produced from contaminated subsurface soil, tar-like material, or groundwater.

  9. Residents wanted to know what chemicals were present in the air of some residentsapartments.


  10. Methane, benzene, toluene, xylene, and ethylbenzene were sampled for and detected in the walls and living areas of some of the apartments and hotel rooms.

  11. Residents have found a tar-like substance in their yards and want to know what it is.


  12. The tar substance is a mixture of alkanes and polycyclic aromatic hydrocarbons. It may be a petroleum-based waste product left over from the refinery operations. Direct contact with the tarry material should be avoided.

  13. Some residents have reported foul smelling odors around their homes and want toknow the source of these odors.


  14. Odors are often hard to trace because they dissipate quickly and can have many sources. Often odors can be detected by people at lower levels then they can be sampled and analyzed for. High levels of methane in soil gas have been reported in areas of the site. Residual materials buried in the old waste impoundments may be another source of odors. Without further investigation, it is not possible to determine if the site contaminants are responsible for these odors. It is also possible that the odors are unrelated to the site.

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