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PUBLIC HEALTH ASSESSMENT

ILADA ENERGY COMPANY
EAST CAPE GIRARDEAU, ALEXANDER COUNTY, ILLINOIS


ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

The tables in this section list the contaminants of concern. The contaminantsare evaluated in the subsequent sections of the Public Health Assessmentand a determination is made whether exposure to them has public healthsignificance. The contaminants are being selected and discussed based uponthe following factors (1):

  1. Concentrations of contaminants on and off the site.

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

  3. Comparison of contaminant concentrations and background concentrations, with health assessment comparison values for both carcinogenic and noncarcinogenic endpoints (discussed further below).

  4. Community health concerns.

In the data tables that follow under the On-site Contamination subsectionand the Off-site Contamination subsection, the listed contaminant does notmean that it will cause adverse health effects from exposures. Instead, thelist indicates which contaminants will be evaluated further in the PublicHealth Assessment.


The data tables include the following acronyms:

*

CREG

=

Cancer Risk Evaluation Guide

*

EMEG

=

Environmental Media Evaluation Guide

*

RMEG

=

Reference Dose Media Evaluation Guide

*

MCLG

=

Maximum Contaminant Level Goal

*

MCL

=

Maximum Contaminant Level

*

PMCLG

=

Proposed Maximum Contaminant Level Goal

*

ppm

=

parts per million

*

ppb

=

parts per billion

*

RfD

=

Reference Dose

*

RfC

=

Reference Concentration

Comparison values for health assessment are contaminant concentrations inspecific media that are used to select contaminants for further evaluation.These values include Environmental Media Evaluation Guides (EMEGs), CancerRisk Evaluation Guides (CREGs), and other relevant guidelines. CREGs areestimated contaminant concentrations based on a one excess cancer in a millionpersons exposed over a lifetime. CREGs are calculated from the United StatesEnvironmental Protection Agency (EPA) cancer slope factors. The EPA's MaximumContaminant Level Goal (MCLG) is a drinking water health goal. EPA believesthat the MCLG represents a level that no known or anticipated adverse effecton the health of persons should occur which allows an adequate margin ofsafety. Proposed Maximum Contaminant Level Goals (PMCLGs) are MCLGs thatare being proposed. Maximum Contaminant Levels (MCLs) represent contaminantconcentrations that EPA deems protective of public health (considering theavailability and economics of water treatment technology) over a lifetime(70 years) at an ingestion rate of 2 liters water per day. While MCLs areregulatory concentrations, PMCLGs and MCLGs are not. EPA's Reference Dose(RfD) and Reference Concentration (RfC) are estimates of the daily exposureto a contaminant that is unlikely to cause adverse health effects(1). EPA's Rfd is used to calculate the ReferenceDose Media Evaluation Guide (RMEG).

Compounds for which none of the above health comparison values exist willbe considered as contaminants of potential concern and will be assessed inthe remainder of the health assessment. Known or suspected human carcinogenswill also be included if no cancer comparison value exists.

A. ON-SITE CONTAMINATION

Removal Action

To assess the type and quantity of contaminated materials, and to determineworker health and safety requirements, sampling of the tank contents andsurface soil was conducted by Dames & Moore in May and August 1989, priorto the Removal Action. The tank sampling data indicated that some ofthe tanks contained aqueous liquids, oil sludge, and/or waste oils, withvariable amounts of chlorinated solvents, heavy metals, and/or PCBs. Allof this material was removed from the site and disposed during removalactivities.

Surface soil samples collected prior to the Removal action identified areasof PCB contamination (Table 1). The various metalsdetected at concentrations greater than comparison values included arsenic,cadmium, and chromium. A visibly stained area that was sampled identifieda low level of 2-methylnaphthalene. This stained area was excavated and disposedas part of the 106 Removal Action (18).

A sample collected near the office indicated the presence of various isomersof dioxins and furans. The most toxic compound of this group,2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), however, was not detected. Manystudies have been performed on TCDD, however, there is little known aboutthe majority of other dioxins and furans. In order to conservatively estimatethe potential human health effects from exposure to the complex mixturesof dioxins and furans, toxicity equivalency factors (TEFs) were developedbased on the compound's toxicity relative to TCDD, with 1 being the mosttoxic or equivalent to TCDD, and 0 being relatively nontoxic. The total TEFsfor all the dioxin/furan isomers are then compared to the TCDD value.

The 106 Removal Action was initiated in December 1989 and included removalof all tanks, piping, contents, structures, debris, and grossly contaminatedsoils. The majority of the removal shipments occurred during the period May1990 through March 1991. A total of 442,164 gallons of oil and sludge wereburned as waste fuel in kilns; 142,700 gallons of PCB contaminated oil andsludge were incinerated; 865,700 gallons of contaminated water were treatedand discharged; 1,055 cubic yards of soil and miscellaneous debris were disposedas special waste; 637 cubic yards were disposed as demolition debris; 50cubic yards of PCB contaminated soil (resulted from small spills during removalactivities) were landfilled; and 1,264 tons of steel were recycled by melting(18). All of the disposal activities weredone in accordance with USEPA and IEPA approvals(18).

Table 1.

Range of Contaminant Concentration in
Pre-Removal On-site Surface Soils (0-6 inches deep)
Contaminant Concentration
Range (ppm)

Date

Comparison Value
ppm Source
Arsenic

3.1-7.5

8/89

0.4

CREG

Cadmium

ND-2.7

8/89

0.4

EMEG

Chromium

3.0-23.0

8/89

10

RMEG

Lead

8.8-510

8/89

none

carcinogen

Zinc

31.3-361

8/89

600

RMEG

2-Methylnaphthalene

ND-3.1

8/89

none

none

Dioxin/Furan (TEFs)

ND-0.00198

8/89

0.000002

EMEG

PCBs

ND-31.0

5/89

0.09

CREG

Reference - 18

Post-Removal

Soil

Phase I soil sampling was performed during the period March through May 1990and consisted of surface soil samples (0-6") from two discrete areas,(1) an area near the former boiler buildingand (2) in the southeast corner; soil samplesfrom intermediate and deep boreholes; and soil samples from test pits dugalong the former underground pipeline south of the levee. Phase IA sampling,conducted in September 1990, consisted of soil samples from shallow soilborings; surface soil samples from the area of the former small and intermediatetanks; and additional soil samples along the former pipeline south of thelevee. Phase II was conducted in April, May, and September 1991, and consistedof soil samples from shallow soil borings; and discrete surface soil samplesfrom areas of former tanks and the former office building.

Table 2 reports the contaminants and concentrationrange identified in surface soil samples. The surface soil was identifiedas soil at 0-6 inches deep. Table 3 reports on-sitesubsurface soil sample results and includes bore samples collected at variouslevels while Table 4 reports the range of contaminantsin the soil along the former pipeline south of the levee. Metals were generallydetected at levels comparible to background levels, however, some areas wereidentified with slightly elevated levels of lead, arsenic, manganese, andzinc. Polynuclear aromatic hydrocarbons (PAHs) were identified in additionto 2-methylnaphthlene and naphthalene. Isolated areas of low levels of PCBsand dioxin/furans were also reported. One subsurface sample identified anelevated level of pentachlorophenol.

Table 2.

Range of Contaminant Concentration in Post Removal On-Site Surface Soils(0-6 inches deep) - Phase I/IA & Phase II

Contaminant
Phase I/IA
Concentration
Range (ppm)

Date
Comparison
Value
Phase II
Concentration
Range (ppm)


Date

ppm Source
Arsenic 5.9 - 17.2 5/90 0.4 CREG ND - 5.4 9/91
Cadmium ND - 1.3 9/90 0.4 EMEG 0.62 - 1.0 9/91
Chromium 14.8 - 25.0 9/90 10 RMEG 2.2 - 19.9 9/91
Lead 28.3 - 47.6 9/90 none carcinogen 3.9 - 183 9/91
Manganese 291 - 484 9/90 10 RMEG 44.2 - 419 9/91
Zinc 71 - 922 5/90 600 RMEG 9.8 - 103 9/91
Total PAHs-C ND - 4.46 9/90 0.1 CREG ND - 2.39 9/91
Total PAHs ND - 4.07 9/90 60 RMEG ND - .413 9/91
2-Methylnaphthalene ND - 2.1 9/90 none none ND - .024 9/91
PCBs ND 9/90 0.09 CREG ND - .130 9/91
Dioxin/Furans (TEFs) ND 9/90 0.000002 EMEG ND-.000007 9/91

Reference - 18;
ND = not detected;
Total PAHs - C = carcinogenic PAHs - compared to benzo(a)pyrene
Total PAHs = non-carcinogenic PAHs - compared to Pyrene

Table 3.

Range of Contaminant Concentrations in On-site Subsurface Soils for Phase I/IA & Phase II
Contaminant Phase I/IA
Concentration
Range (ppm)
Date Phase II
Concentration
Range (ppm)
Date Comparison Value
ppm Source
Arsenic

2.6 - 11.0

9/90

0.99 - 13.4

9/91

0.4

CREG

Chromium

ND - 27.4

9/90

4.2 - 34.8

9/91

10

RMEG

Cadmium

ND - 1.8

9/90

0.64 - 2.8

9/91

0.4

EMEG

Lead

9.7 - 51.8

9/90

3.5 - 424

9/91

none

carcinogen

Manganese

124 - 1670

9/90

66.1 - 1040

9/91

10

RMEG

Zinc

19 - 200

9/90

14.5 - 372

9/91

600

RMEG

Total PAHs-C

ND - 2.41

9/90

ND - 17.02

9/91

0.1

CREG

Total PAHs

ND - 5.0

9/90

ND - 179.9

9/91

60

RMEG

2-Methylnaphthalene

ND - 7.3

9/90

ND - 560

9/91

none

none

Endosulfan Sulfate

ND - 0.15

9/90

ND

9/91

0.4

EMEG

Dioxin/Furans (TEFs)

ND - 0.0000004

9/90

NA

-

.000002

EMEG

Benzene

ND

9/90

ND - 1.7

9/91

20

CREG

Pentachlorophenol

ND

9/90

ND - 20

9/91

2

EMEG

Naphthalene

ND

9/90

ND - 170

9/91

none

none

PCBs

ND

9/90

ND - 6.6

9/91

0.01

EMEG

Reference - 18
ND = not detected; Total PAHs-C = carcinogenic PHAs -compared to benzo(a)pyrene
NA = not analyzed; Total PAHs - compared to Pyrene
Endosulfan sulfate - compared to endosulfan

.

Table 4.

Range of Contaminant Concentrations Detected in Soil Along Pipeline
Contaminant Concentration
Range (ppm)
Date Comparison Value
ppm Source
Arsenic ND - 5.8 9/90

0.4

CREG

Chromium 4.2 - 17.9 9/90

10

RMEG

Lead 4.4 - 18.5 9/90

none

carcinogen

Zinc 12.6 - 65.2 9/90

600

RMEG

Total PAHs-C ND - 0.353 9/90

0.1

CREG

Total PAHs ND - 0.424 9/90

60

RMEG

2-Methylnaphthalene ND - 1.20 9/90

none

none

Dioxins ND-0.000001 5/90

.000002

EMEG

Reference - 18
ND = not detected
PAHs - compared to Pyrene

Groundwater

The Phase I groundwater sampling, performed during the period February throughMay 1990, consisted of analysis of water samples from six IEPA monitoringwells (installed in 1986); installation of ten additional groundwater monitorwells; measurement of water levels in on-site monitor wells; and collectionof Mississippi River stage data. Phase IA groundwater sampling activitieswere performed in September 1990. These activities included the installationof one additional on-site monitoring well and five off-site monitoring wellsand a round of sampling from all existing monitoring wells. Phase II includedanother set of water samples from all monitoring wells. This work was performedin August 1991.

Low levels of metals, pesticides, volatile organic compounds (VOCs), andPCBs were identified in the samples. Several VOC tentatively identified compounds(TICs) were reported and tentatively identified as a group indicative ofweathered petroleum hydrocarbons (18).Semi-volatile organic compounds were identified includingdi(2-ethylhexyl)phthalate (DEHP) and 2-methylnaphthalene. Benzene was identifiedin the groundwater, however, the samples were from borings, not finishedmonitor wells. Table 5 illustrates maximum concentrationsfor those contaminants that were detected at levels greater than the comparisonvalue.

Table 5.

Maximum Contaminant Concentrations in On-Site Groundwater - Wells & Shallow Borings - Phase I/IA & Phase II
Contaminant

Level (ppm)
Phase I/IA

Date Level
(ppm)
Phase II
Date

Comparison Value

ppm Source
Arsenic

0.130

9/90

0.110

9/91

.00002

CREG
Chromium

0.339 *

5/90

ND

9/91

0.05

RMEG
Manganese

9.010

9/90

5.54

9/91

0.05

RMEG
Dieldrin

0.002

5/90

ND

9/91

0.000002

CREG
Chlordane

0.0006

5/90

ND

9/91

0.00003

CREG
Heptachlor

0.0001

5/90

ND

9/91

0.000008

CREG
Di(2-ethylhexyl)phthalate

0.062

9/90

0.007

9/91

0.003

CREG
2-Methylnaphthalene

0.023

9/90

ND

9/91

0.02^

LTHA
Benzene

0.021 **

5/90

9.8 **

9/91

0.001

CREG
Ethylbenzene

ND

9/90

0.82 **

9/91

1

RMEG
1,1,2,2-Tetrachloroethane

ND

9/90

0.005 **

9/91

0.0002

CREG
Dibromochloromethane

ND

9/90

0.005 **

9/91

0.0004

CREG
PCBs

ND

9/90

0.0004

9/91

0.000005

CREG

Reference - 18
ND = not detected
* = sample from Ilada well
** = sample from shallow boring
^ = 2-methylnaphthalene - compared to naphthalene

The elevated level of benzene detected in groundwater samples from shallowborings appeared to be in a localized area. To investigate this occurrencefurther, USEPA required an additional shallow groundwater monitor well beinstalled in the area of the contamination. The well was installed in March1992. During the initial sampling of the well, an approximately four inchthick floating layer of petroleum product was encountered. The thicknessof the contamination layer in the ground was not known. The petroleum productappeared to be aviation fuel based on a screening analysis(17). Laboratory analysis dated April 28,1992, identified 16,000 parts per million (ppm) benzene; 140,000 ppm toluene;20,000 ppm ethyl benzene; and 61,000 ppm total xylenes(17).

Surface Water

A surface water investigation was conducted during Phase II. No permanentsurface water feature was present on the site, however, periodic floodingand ponding of water occurred due to the proximity of the Mississippi Riverand poor surface drainage. Surface water was present on site during the studyperiod when flooding occurred in the spring and summer of both 1990 and 1991(18). Laboratory results of samples illustratedlimited contamination with metals and DEHP (Table 6).

Table 6.

Range of Contaminant Concentrations in On-site Surface Waters (SE Corner)
Contaminant Concentration
Range (ppm)
Date

Comparison Value

ppm Source
Arsenic

0.0039 - 0.0061

5/91

0.00002

CREG

Chromium

ND - 0.002

5/91

0.05

RMEG

Lead

0.0066 - 0.022

5/91

0.0075

STATE

Manganese

0.142 - 0.321

5/91

0.05

RMEG

Zinc

0.0077 - 0.0167

5/91

3.00

RMEG

Di(2-ethylhexyl)phthalate

ND - 0.013

5/91

0.003

CREG

Reference - 18
ND = not detected

B. OFF-SITE CONTAMINATION

As a result of previous investigations at the site, limited off-site samplingwas conducted prior to the 106 Removal Action and the remedial investigation.In 1983, two private drinking-water wells were sampled. Samples were analyzedfor priority pollutant organic compounds, but none were detected(16). In 1985, soil samples from the leveesouth of the site collected by IEPA showed no detectable levels of dioxins,furans, or PCBs (16). In May 1991, as partof the remedial investigation, off-site samples were collected from surfacewater, soil, monitoring wells, private wells, and a public water supply well.

Soil

During periods of site flooding in 1990 and 1991, water was observed drainingoff the southeastern portion of the site into a ditch running eastward towardthe Highway 3 drainage ditch (18). Three soilsamples were collected from the ditch that received runoff from the southeasternportion of the site and six samples were collected from areas located ½to 1 mile west and north of the site (Figure4). The soil sampling locations were typically dry, but were subjectto periodic flooding and were therefore referred to as soil/sediment samplesin the RI (18). Since the samples were fromareas that were not permanent surface water features and were typically dry,they are discussed as "soil" samples for purposes of this document. A totalof nine off-site soil samples were collected.

Analysis of the off-site soil samples identified low levels of organiccontamination including DEHP and PAHs. No carcinogenic PAHs were detected.The only pesticide detected was DDT and this was detected at very low levelsat two of the sampling sites. PCBs were not detected at any of the samplinglocations. The off-site soil samples were not analyzed for dioxin/furan isomers.None of the sampling locations exhibited elevated levels of heavy metals.Table 7 illustrates the range of contaminant concentrationin the off-site surface soil samples. The surface soil samples were identifiedas soil at 0-6 inches deep.

Table 7.

Range of Contaminant Concentrations in Off-site Surface Soil Samples(0-6 inches deep)
Contaminant Concentration
Range (ppm)
Date Comparison Value
ppm Source
Arsenic

3.9 - 11.3

5/91

0.4

CREG

Chromium

12.5 - 23.7

5/91

10

RMEG

Cadmiumm

ND - 1.2

5/91

0.4

EMEG

Lead

11.2 - 23.6

5/91

none

carcinogen

Manganese

352 - 828

5/91

10

RMEG

Zinc

59.5 - 113

5/91

600

RMEG

Di(2-ethylhexyl)phthalate

ND - 0.17

5/91

40

RMEG

Total PAHs

ND - 0.038

5/91

60

RMEG

Reference - 18
Total PAHs (non-carcinogenic) - compared to Pyrene

Groundwater

Five off-site monitoring wells were installed along the southern and westernedges of the site in September 1990 (Figure5). Table 8 reports the contaminants and concentrationrange detected in the wells. No metals were detected at elevated levels.A low level of benzene was detected in one well during the May 1991 roundof sampling, but was not detected in any of the wells in the initial roundof samples collected in September 1990. Analyses of the samples collectedSeptember 1990 reported low levels of DEHP, however, this compound was notdetected in the May 1991 samples.

Table 8.

Range of Contaminant Concentrations in Off-site Groundwater Monitoring Wells
Contaminant Concentration
Range (ppm)
Date

Comparison Value

ppm Source
Arsenic

ND

9/90

.00002

CREG
Chromium

ND

9/90

0.050

RMEG
Cadmium

ND

9/90

0.002

EMEG
Lead

ND - 0.010

9/90

.0075

STATE
Zinc

ND - 0.017

5/91

3.00

RMEG
Manganese

0.04 - 0.42

9/90

0.05

RMEG
Benzene

ND - 0.001

5/91

0.001

CREG
Di(2-ethylhexyl)phthalate

ND - 0.011

9/90

0.003

CREG

Reference - 18
ND = not detected

In addition to the five off-site monitoring wells, three private residentialwells and a public water supply well were sampled during the remedialinvestigation. Water samples were collected from these four wells in Februaryand March 1990. Two of the residential wells are located directly north ofthe site while the third residential well is located in the village of Gale,southeast of the site. The public water supply that was sampled is locatedin McClure approximately 5 miles northeast of the site(Figure 6). The residential well inGale and the McClure public water supply well were sampled for possible useas a source of drilling water for use during the removal action, not as partof the groundwater investigation. The sampling results, however, are includedin this discussion for off-site groundwater. Table 9reports the contaminants and concentration range detected in the wells sampled.

The calculated groundwater flow direction data indicated the predominantflow direction was southwesterly toward the Mississippi River. Flow directionchanges and reversals, however, were observed in conjunction with high riverstage levels (18). Generally, the residentialwells located north of the site would appear to be upgradient, although aspreviously stated, there is some fluctuation of the groundwater due tofluctuations of the river stage. The McClure well, located five miles northof the site, appears to be effectively upgradient. The Gale residential wellwas also reported to be upgradient as demonstrated by water levels in thewell that were measured to be higher than levels on the site(18).

Results of the Gale well sample identified arsenic at a level above thecomparison value. This arsenic occurrence was previously discussed in theCommunity Health Concerns section. Low levels of organic contaminants weredetected in the wells located north of the site, including DEHP in residentialwell W3 and the pesticide, heptachlor epoxide, in residential well W4. Benzoicacid was also detected in well W3, however, at a level well below healthcomparison values.

A second round of sampling of the two private wells north of the site wasperformed on November 4, 1993. This sampling was conducted in responseto the high river stage of the Mississippi River. No organic contaminantswere detected during this round of sampling. Levels of manganese andzinc were lower than those detected during the first round of sampling andchromium was not detected in PrW-3 during the 1993 sampling activities(38).

.

Table 9.

Range of Contaminant Concentrations in Off-site Public and Private Water Wells (3/90)
Well Name* Arsenic
(ppm)
Chromium
(ppm)
Cadmium
(ppm)
Lead
(ppm)
Manganese
(ppm)
Zinc
(ppm)
A
(ppm)
B
(ppm)
McClure-1

ND

ND

0.0057

0.0039

0.117

0.968

0.032

ND

PrW-2

0.0527

ND

ND

0.0034

0.311

0.227

ND

ND

PrW-3

ND

0.0044

ND

ND

0.418

0.162

0.006

ND

PrW-4

ND

ND

ND

ND

0.7377

0.103

ND

0.000008

Comparison Value (ppm)

0.00002

0.050

0.002

.0075 0.05 3.00 0.003

0.000004

Source

CREG

RMEG

EMEG

STATE RMEG RMEG CREG

CREG

Reference - 18; McClure -Public Water Supply; PrW - Private Wells
* See Figure #6 for Location; A =Di(2-ethylhexyl)phthalate
ND = not detected; B = Heptachlor epoxide

Surface Water

As stated previously, water was observed to run off site during periods offlooding. Following an occurrence of heavy rains in May 1991, three off-sitesurface water samples were collected from the drainage ditch that receivedrunoff from the southeastern portion of the site. Two surface water sampleswere also collected about one-half to one mile west and north of the site.These sites were not permanent surface water features, but were instead typicallydry locations that had become inundated from the heavy rains. The surfacewater samples were collected from the same areas that the off-site soil sampleswere collected. Table 10 reports the contaminantsand concentration range. The samples collected from the drainage ditch receivingsite runoff illustrated the highest levels of the contaminants detected whichincluded metals and DEHP. No PCBs or pesticides were detected.

Table 10.

Range of Contaminant Concentrations in Off Surface Waters (5/91)
Contaminant

Concentration Range
(ppm)

Comparison Value

ppm Source
Arsenic

0.0022 - 0.0107

.00002

CREG

Chromium

0.002 - 0.0068

0.050

RMEG

Cadmium

ND - 0.0096

0.002

EMEG

Lead

0.002 - 0.0177

.0075

STATE

Manganese

0.038 - 0.518

0.05

RMEG

Zinc

0.0106 - 0.0423

3.00

RMEG

Di(2-ethylhexyl)phthalate

0.001 - 0.040

0.003

CREG

Reference - 18
ND = not detected

Toxic Chemical Release Inventory

A search of the EPA Toxic Chemical Release Inventory (TRI) for the site andlocal area was conducted. The TRI network did not list any facilities havingchemical releases in the vicinity of the site (area covered by the zip code:62990). The TRI contains data for the years 1987-1992(23).

C. QUALITY ASSURANCE AND QUALITY CONTROL

Data validation of the analytical results was conducted to assess the dataquality and usability. A report of the laboratory and field quality controlwas included in the RI report and this information was reviewed for purposesof this health assessment. The quality control report stated the percentageof valid data or completeness well exceeded 95 percent(18). If the data results were in question,a data clarifier was used. Data marked with the clarifier "J" and "B" wereincluded in the previous tables listing the range of contaminant concentrations.The "J" indicated the associated value for organics only was an estimatedquantity as a result of the value obtained being greater than or equal tothe Instrument Detection Limit (IDL), but less than the Contract RequiredQuantitation Limit (CRQL) after it was adjusted for dilution and percentmoisture. The "B" indicated the reported value for inorganics only was obtainedfrom a reading that was less than the CRQL, but was greater than or equalto the IDL.

Methylene chloride and acetone, common laboratory contaminants, were foundin various trip blanks. Methylene chloride, chloroform, toluene, DEHP,tetrachloroethane, and various metals were identified in some field blanks.Field and trip blanks were used to evaluate sampling and analytical accuracy.

D. PHYSICAL AND OTHER HAZARDS

Prior to the 106 Removal Action, physical hazards did exist. The storagetanks on-site contained over one million gallons of oily waste. The lowflashpoints of the oily waste could have caused the waste to be ignited ordetonated by lightning or vandalism. The rusting, deteriorating tanks alsoposed a physical hazard to site trespassers. No current physical hazardsexist, however, since the only physical remnant on the site is the 7-foothigh perimeter fence.

PATHWAYS ANALYSES

To determine whether nearby residents are exposed to contaminants migratingfrom the site, the environmental and human components that lead to humanexposure are evaluated. The pathways analysis consists of five elements:A source of contamination, transport through an environmental medium, a pointof exposure, a route of human exposure, and an exposed population(1).

IDPH categorizes an exposure pathway as a completed or potential exposurepathway if the exposure pathway cannot be eliminated. Completed pathwaysrequire that the five elements exist and indicate that exposure to a contaminanthas occurred in the past, is currently occurring, or will occur in the future.Potential pathways, however, require that at least one of the five elementsis missing, but could exist. Potential pathways indicate that exposure toa contaminant could have occurred in the past, could be occurring now, orcould occur in the future. An exposure pathway can be eliminated if at leastone of the five elements is missing and will never be present(1). Table 11 identifiesthe completed and potential exposure pathways. The discussion that followsthe table incorporates only those pathways that are important and relevantto the site.

Table 11.

COMPLETED AND POTENTIAL EXPOSURE PATHWAYS
PATHWAY NAME EXPOSURE PATHWAY ELEMENTS TIME
SOURCE ENVIRONMENTAL
MEDIA
POINT OF
EXPOSURE
ROUTE OF
EXPOSURE
EXPOSED
POPULATION

Completed Exposure Pathway

Private Well Ilada Energy Site
(site)
Groundwater Residences (tap) Ingestion
Inhalation
Dermal Contact
Residents North of
Site
Past
Present
Future

Potential Exposure Pathways

Surface Water Site Surface Water Site Drainage Areas Ingestion
Dermal Contact
Children &
Residents North of
Site
Past
Present
Future
Surface Soil Site Surface Soil Site Soils Ingestion Site Trespassers Past
Present
Future
Ambient Air Site Air Site & Nearby
Residences/Yards
Inhalation Site Trespassers &
Residents North of
Site
Past
Present
Future
Private Well Site Groundwater Residences (tap) Ingestion
Inhalation
Dermal Contact
Private Well Users Future

A. COMPLETED EXPOSURE PATHWAYS

Private Well Pathway

Past, current, and future exposure pathways are possible from contaminatedgroundwater in private wells. This exposure pathway is being included asa completed pathway, however, some question remains as to whether surroundingresidential wells could actually be impacted by the site. Groundwatermeasurements taken during the remedial investigation indicated groundwaterflow predominantly toward the Mississippi River in a southerly to southwesterlydirection (18). No private wells are locatedbetween the site and the river. During periods of high river stages, however,the groundwater did exhibit changes in flow direction. The nearest residences(three), located 1/4 mile north of the site, rely on private wells for watersupplies. Private wells were sampled from two of the residences north ofthe site. Samples from one of the wells reported a low level of DEHP (0.006ppm) while the other reported 0.000008 ppm heptachlor expoxide.

Heptachlor epoxide is a breakdown product of the pesticide, heptachlor.Heptachlor was used to kill insects on crops in the 1960s and 1970s. It wasalso a popular chemical for use around homes for the control of termites.Heptachlor epoxide is not very soluble in water, but rather remains in soilfor long periods of time (8). The occurrenceof heptachlor epoxide in the residential well is most likely not a resultfrom the site, but rather a result of past agricultural use in the surroundingfields or from possible previous applications for termite control on theresidence. The level detected is well below ATSDR health comparison valuesand is not considered a health concern. Due to these factors, heptachlorepoxide will not be addressed further.

DEHP was detected in one of the residential wells located north of this site.It was also detected in on-site soils and monitor wells, indicating thaton-site groundwater may be impacting the groundwater north of the site. However,it should also be mentioned that DEHP was identified in field blank samplesand that detection in the well sample may have been due to laboratorycontamination. A field duplicate sample for this well did not illustratea detectable level of DEHP.

A door-to-door survey of residences within a 2-mile radius of the site wasconducted by Dames & Moore between October 1990 and February 1991(18). The survey identified two occupantsliving at the residence having the well with detected DEHP contamination.Two additional residences are located in the same area, one with four occupantsand the other with three occupants. A total of approximately 10 individualslive 1/4 mile north of the site. Although only one well illustrated levelsof DEHP, all three wells were reported by the landowners to be 30 to 35 feetdeep. The wells serving the other two residences could possibly be affectedin the future.

Exposure to DEHP by residents of the households could occur from absorptionacross the skin during showering or bathing and by ingestion from drinkingor cooking with contaminated water.

B. POTENTIAL EXPOSURE PATHWAYS

Surface Water Pathway

Periodic flooding at the site has resulted in water draining off the site.During a flood in 1973, flood waters reportedly reached the residence located1/4 mile north of the site. The 1973 flood was reported by the landownerto be the worst in the past 40 years (17).Flood waters from the site could result in past, current, and future exposurepathways. Although surface water samples collected during recent periodsof flooding exhibited low levels of contamination, the surface water featuresare only temporary features resulting from periodic heavy rains. Since thesesurface waters are temporary and occur in a sparcely populated area, ingestionor dermal contact of site impacted surface waters do not appear to be significantexposure pathways and will not be considered further.

Surface Soil Pathway

Past, current, and future exposure pathways are possible from contaminationof surface soils at the site. Prior to the December 1989 removal action,Ilada Energy Company workers and site trespassers may have been exposed tocontaminated surface soils through dermal contact with the contaminated soils,inhalation of wind-blown contaminated dust, and incidental ingestion ofcontaminated soils. Human exposure to contaminated soil may also have occurredto on-site workers during the removal activities. The results from the soilsamples taken after the removal action indicated low levels of contamination.Remaining surface soil contamination is cause for possible present and futureexposures to site visitors (including possible tresspassers). However, thenumber of such exposures should be minimal because the site is fenced, gated,and located in a sparcely populated area. These completed exposures are notlikely to be of health concern because the surface soil has low contaminationlevels and visits are likely to be of short duration. Since surface soildoes not appear to be a pathway of health concern, it will not be consideredfurther.

Ambient Air Pathway

Inhalation of site contaminants by nearby residents or site trespassers couldbe a potential exposure pathway. Chemicals such as the VOCs could volatilizeor evaporate into the air from contaminated soil. Other chemicals such asmetals or PCBs adsorbed to dust particles could become suspended in air.The only on-site or off-site air monitoring performed was during on-siteremoval activities to assure worker safety, but no quantitative data wereobtained.

Petroleum-like odors were noticed near storage tanks during the site visitprior to any removal activities. As stated previously, however, no monitoringdata were available that would identify what contaminants were in the airon-site or if any were migrating off-site to nearby residents. Followingthe removal action, the tanks and their contents no longer remain. Areasof surface soil contamination remain on-site, however, vegetative cover on-sitewould most likely reduce fugitive dust emissions. Exposure by this pathwayalso does not appear to be a concern and will not be considered further.

Private Well Pathway

Benzene was not detected in any residential wells, however, it was detectedin groundwater from shallow borings on-site. Preliminary data from a monitorwell that was installed on-site in March 1992, identified a floating layerof a petroleum product that contained 16,000 ppm benzene. Although groundwaterflow toward residential wells has not actually been established, the possibilityexists that on-site contaminated groundwater may affect off-site residentialwells north of the site. If this occurred, benzene could possibly migrateoff-site to the residential wells resulting in exposure to occupants in thefuture.

PUBLIC HEALTH IMPLICATIONS

A. TOXICOLOGICAL EVALUATION

Introduction

This section will discuss the health effects in persons exposed to specificcontaminants, evaluate applicable state and local health databases, and addressspecific community health concerns. To evaluate health effects, ATSDR developeda Minimal Risk Level (MRL) for contaminants commonly found at hazardous wastesites. The MRL is an estimate of daily human exposure to a contaminant belowwhich non-cancer, adverse health effects are unlikely to occur. MRLs aredeveloped for each route of exposure, such as ingestion and inhalation, andfor the length of exposure, such as acute (less than 14 days), intermediate(15 to 365 days), and chronic (greater than 365 days). ATSDR presents theseMRLs in Toxicological Profiles. These chemical-specific profiles provideinformation on health effects, environmental transport, human exposure, andregulatory status (1). In the following discussionof the contaminants of concern, ATSDR Toxicological Profiles fordi(2-ethylhexyl)phthalate, benzene, and arsenic were used.

Di(2-ethylhexyl)phthalate

Di(2-ethylhexyl)phthalate, commonly referred to as DEHP, was identified inone of the residential wells located north of the site. DEHP is a chemicalused in the manufacture of plastic products such as imitation leather, flooring,food packaging materials, and children's toys(6). It is also used as hydraulic fluid andfluid in electrical capacitors. Due to the wide use of DEHP, it is widelydistributed in the environment and as a result, many potential routes ofexposure can occur. Contamination of food can occur during processing, handling,transportation, and packaging, or DEHP may evaporate from plasticized productsduring their use (6). Exposure from drinkingwater may occur from some kinds of flexible plastic tubing used to carrythe water. Individuals who may be susceptible to higher exposures than thegeneral population may be dialysis patients and hemophiliacs receiving largequantities of blood, since their treatment involves use of plastic medicalsupplies such as storage bags and tubing used for blood transfusions or kidneydialysis (6).

Generally, the very low levels of DEHP that people are normally exposed to,ranging from 0.3-2.0 mg/day, have not been shown to cause adverse healtheffects. In animal studies, ingestion of doses of approximately 80 mg/kg/dayand higher of DEHP has produced liver and testes damage, affected reproduction,and produced birth defects. It was also found to cause cancer in rats andmice. None of these effects, however, has been documented in humans(6).

Users of the well water contaminated with DEHP would be exposed to thiscontaminant primarily by ingestion. Using the level detected in the well(0.006 ppm), the ingestion exposure for adults (0.00017 mg/kg/day) and children(0.0006 mg/kg/day) does not exceed USEPA's oral reference dose (0.02 mg/kg/day)(1). In calculating the ingestion dose, itwas assumed that adults drink 2 liters (66 ounces) of tap water each dayand weigh 70 kg (154 pounds) (1). For children,it was assumed they drink 1 liter (33 ounces) of tap water each day and weigh10 kg (22 pounds) (1). A reference dose isan estimate of a daily exposure to the general human population that is likelyto be without an appreciable risk of deleterious effects during a lifetimeof exposure (1). Therefore, adverse healtheffects are unlikely to occur for those persons who consume this water. Thisstatement is based on the level of contamination detected at the time ofsampling. The research regarding adverse health effects from ingestion ofDEHP is based on animal studies only. Similar information based on humanexposures to DEHP is not available (1).

No reference concentration or minimal risk level was developed for DEHP forinhalation or dermal exposure routes. There was neither human, nor animaldata available on the absorption of DEHP for exposure via inhalation. DEHPis relatively nonvolatile, indicating that partitioning into the atmospherewould be somewhat limited (6). No data areavailable on the absorption of DEHP to humans dermally exposed, however,animal studies indicated DEHP appears to be poorly absorbed when appliedto the skin of rats (6). Based on this information,neither inhalation nor dermal contact of DEHP contaminated water appear tobe significant routes of exposure.

The USEPA has catagorized DEPH as a probable human carcinogen. They havefound sufficiant evidence of cancer in studies of animals exposed to DEPH,but inadequate evidence of cancer in human studies. IDPH estimated that thelevel of DEPH (0.006 ppm) detected in the residential well would pose noincreased risk to exposed individuals of developing cancer over a lifetime.

Benzene

Although benzene was not detected in any residential wells, it was detectedin groundwater on-site. Benzene was also detected in one off-site monitoringwell, although, this well is located south of the site rather than northwhere the nearest residences are located. Because exposure to benzene byingestion, inhalation, or dermal contact to residents who utilize the wellis not currently occurring nor has apparently occurred in the past, it isnot possible to calculate an exposure dose. It seems necessary, however,to discuss benzene since contaminated groundwater on-site may affect off-sitewells in the future.

Benzene is a major industrial chemical made from coal and oil and is usedas a component in gasoline. It is also utilized in industry to make sometypes of plastics, detergents, and pesticides(3). Benzene is very volatile and can evaporatevery quickly. Probably the most common exposure is from breathing air containingbenzene. In addition to inhalation, benzene can also be absorbed into thebody following ingestion and dermal contact(3).

Benzene is considered to be a human carcinogen because it has been shownto cause cancer (leukemia) in laboratory animals exposed to high levels andin workers exposed to high levels over a long period of time(3). Long term exposure to benzene may alsoaffect normal blood production resulting in severe anemia and internal bleeding.Additional human and animal data suggest benzene may be toxic to the body'simmune and reproductive systems (3).

Arsenic

Arsenic was a chemical of concern in one of the residential wells in thetown of Gale which is located about 1 mile southeast of the site. Of thenine residential wells sampled, only one indicated a slightly elevated levelof arsenic (52.7 ppb). The source of arsenic contamination is not believedto be the Ilada site, but is likely localized in the ground. Since arsenicis a chemical element that is commonly found in rock, it is not unusual tofind it in the soil and dissolved in well water.

Ingestion of arsenic levels ranging from about 300 to 30,000 ppb may causestomach and intestinal irritation, with symptoms such as pain, nausea, vomiting,and diarrhea. Arsenic concentrations of around 100 to 200 ppb, however,do not seem to produce noticeable noncancer risks(2). A characteristic effect of arsenic exposureis skin abnormalities described as excessive pigmentation and the developmentof small corn-like growths on the palms, soles, and trunk of the body. Theseskin changes do not generally result in acute health problems to the affectedindividual, however, a small number of these growths may progress to skincancer. It is also reported that ingestion of arsenic may increase the riskof other types of cancer including liver, bladder, kidney, and lung. Basedon sufficient human evidence, the USEPA has catagorized arsenic as a knownhuman carcinogen (2).

IDPH calculated an estimated exposure dose for arsenic based on the concentrationdetected in the residential well. Utilizing this estimated dose it was determinedthat persons exposed to arsenic in the residential Gale well may have a moderateincreased risk of developing cancer over a lifetime.

B. HEALTH OUTCOME DATA EVALUATION

Since carcinogens are associated with this site, the state cancer registrywould seemingly provide relevant information. However, the study populationis too small for a relevant cancer incidence evaluation. Cancer incidenceinformation for Alexander County as a whole would not truly reflect anyoccurrence related only to the site.

The adverse pregnancy outcome database would also be relevant since sitecontaminants such as benzene have been associated with reproductive effects,however, as with the cancer incidence, the small study population would bedifficult to correlate with county wide data.

C. COMMUNITY HEALTH CONCERNS EVALUATION

As stated previously, the only concern expressed was the arsenic occurrencein the Gale residential well. Because all the residents of Gale rely ongroundwater for their water supplies, there was some concern that other Galewells may also exhibit elevated arsenic. In response to those concerns, asurvey of the wells was conducted and samples for arsenic analysis were collectedfrom the wells. No other wells exhibited elevated levels of arsenic exceptfor the original well.


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