CHEVRON CHEMICAL CO. (ORTHO DIVISION)
ORLANDO, ORANGE COUNTY, FLORIDA
Appendix A. Figures
Figure 1
(0-1 Foot) Before 1992 Cleanup
Contaminants of Concern
Maximum Concentration
(mg/kg)Total # positive-------- Total # samples
Background Concentration
(mg/kg)Comparison Value
(mg/kg)
Source
Chlordane
1,400
10/10
<0.1
0.5
CREG DDD
1,600
11/12
<0.02
3
CREG DDT
1,800
11/12
<0.02
2
CREG Dieldrin
4
10/12
<0.02
0.04
CREG Heptachlor Epoxide
<15
0/12
<0.01
0.08
CREG mg/kg - milligrams per kilogram
CREG - Cancer Risk Evaluation Guide (for 10-6 excess cancer risk)
Sources of data: NUS 1990; Brown and Caldwell 1990a
(>1 Foot) Before 1992 Cleanup
Contaminants of Concern
Maximum Concentration
(mg/kg)Total # positive-------- Total # samples
Background Concentration
(mg/kg)Comparison Value
(mg/kg)
Source Chlordane
110,000
302/436
<0.1
0.5
CREG DDD
1,600
240/420
<0.02
3
CREG DDT
1,800
106/426
<0.02
2
CREG Dieldrin
81
87/260
<0.02
0.04
CREG Heptachlor Epoxide
500
3/278
<0.01
0.08
CREG mg/kg - milligrams per kilogram
CREG - Cancer Risk Evaluation Guide (for 10-6 excess cancer risk)
Sources of data: NUS 1990; Dames & Moore 1983; Brown and Caldwell 1990, 1992
(>1 Foot) After 1992 Cleanup
Contaminants of Concern
Maximum Concentration
(mg/kg)Total # positive-------- Total # samples
Background Concentration
(mg/kg)Comparison Value
(mg/kg)
Source Chlordane
350
208/304
<0.1
0.5
CREG DDD
210
145/302
<0.02
3
CREG DDT
58
53/302
<0.02
2
CREG Dieldrin
16
60/227
<0.02
0.04
CREG Heptachlor
Epoxide
3
6/218
<0.01
0.08
CREG mg/kg - milligrams per kilogram
CREG - Cancer Risk Evaluation Guide (for 10-6 excess cancer risk)
Sources of data: NUS 1990; Brown and Caldwell 1992; Task 1994a
Contaminants of Concern
Maximum Concentration
(µg/L)Total # positive-------- Total # samples
Background Concentration
(µg/L)Comparison Value
(µg/L)
Source Chlordane
1,100
13/57
<1
0.03
CREG DDD
49,000
12/57
<0.3
0.1
CREG DDT
140
3/57
<0.3
0.1
CREG Dieldrin
3,800
10/57
<0.1
0.002
CREG Heptachlor
Epoxide
30
3/30
<0.07
0.004
CREG µg/L - micrograms per liter
CREG - Cancer Risk Evaluation Guide (for 10-6 excess cancer risk)
Sources of data: NUS 1990; Dames & Moore 1983; Jammal & Associates 1987; Brown and Caldwell 1990a, 1992.
Contaminants of Concern
Maximum Concentration
(µg/L)Total # positive-------- Total # samples
Background Concentration
(µg/L)Comparison Value
(µg/L)
Source Chlordane
13
1/16
<1
0.03
CREG DDD
3
2/16
<0.3
0.1
CREG DDT
<0.3
0/16
<0.3
0.1
CREG Dieldrin
<0.1
0/16
<0.1
0.002
CREG Heptachlor
Epoxide
<0.1
0/16
<0.07
0.004
CREG µg/L - micrograms per liter
CREG - Cancer Risk Evaluation Guide (for 10-6 excess cancer risk)
Sources of data: NUS 1990; Chevron 1993; PTI 1993
Contaminants of Concern
Maximum Concentration
(µg/m3)Total # positive-------- Total # samples
Background Concentration
(µg/m3)Comparison Value
(µg/m3)
Source Chlordane
0.49
22/57
NA
0.2
EMEG/MRL DDD
0.026
4/57
NA
0.01
CREG DDT
ND
0/57
NA
----
---- Dieldrin
ND
0/57
NA
----
---- Heptachlor Epoxide
ND
0/57
NA
----
---- 1 Air monitoring data were only collected during the 1992 site cleanup.
NA-not analyzed; ND-not detected; µg/m3-micrograms per cubic meter
EMEG/MRL - ATSDR Intermediate Environmental Media Evaluation Guide/Minimal Risk Level
CREG - Cancer Risk Evaluation Guide
Source of data: Brown and Caldwell 1992
Contaminants of Concern
Maximum Concentration
(mg/kg)Total # positive-------- Total # samples
Background Concentration
(mg/kg)Comparison Value
(mg/kg)
Source Chlordane
370
49/49
0.62
0.5
CREG DDD
3
10/49
0.009
3
CREG DDT
3.3
45/49
0.11
2
CREG Dieldrin
2
20/49
0.18
0.04
CREG Heptachlor
Epoxide
0.15
3/49
<0.004
0.08
CREG mg/kg - milligrams per kilogram
CREG - Cancer Risk Evaluation Guide (for 10-6 excess cancer risk)
Source of data: NUS 1990; PTI 1994
Contaminants of Concern
Maximum Concentration
(mg/kg)Total # positive-------- Total # samples
Background Concentration
(mg/kg)Comparison Value
(mg/kg)
Source Chlordane
3.5
17/21
0.62
0.5
CREG DDD
0.007
1/21
0.009
3
CREG DDT
0.34
14/21
0.11
2
CREG Dieldrin
0.3
5/21
0.18
0.04
CREG Heptachlor
Epoxide
<0.004
0/21
<0.004
0.08
CREG mg/kg - milligrams per kilogram
CREG - Cancer Risk Evaluation Guide (for 10-6 excess cancer risk)
Sources of data: NUS 1990; Chevron 1994a, 1994b
Contaminants of Concern
Maximum Concentration
(µg/L)Total # positive-------- Total # samples
Background Concentration
(µg/L)Comparison Value
(µg/L)
Source Chlordane
50
4/19
<1
0.03
CREG DDD
7.5
4/19
<0.3
0.1
CREG DDT
<0.3
0/19
<0.3
0.1
CREG Dieldrin
<0.1
0/19
<0.1
0.002
CREG Heptachlor
Epoxide
<0.07
0/19
<0.07
0.004
CREG µg/L - micrograms per liter
CREG - Cancer Risk Evaluation Guide (for 10-6 excess cancer risk)
Sources of data: NUS 1990; Brown and Caldwell 1992; Chevron 1993; PTI 1993
Contaminants of Concern
Maximum Concentration
(µg/m3)Total # positive-------- Total # samples
Background Concentration
(µg/m3)Comparison Value
(µg/m3)
Source Chlordane
0.49
22/57
NA
0.2
EMEG/MRL DDD
0.026
4/57
NA
0.01
CREG DDT
ND
0/57
NA
----
---- Dieldrin
ND
0/57
NA
----
---- Heptachlor Epoxide
ND
0/57
NA
----
---- 1 Air monitoring data were only collected during the 1992 site cleanup.
2 We assume off-site air quality similar to that at site boundary
NA-not analyzed; ND-not detected; µg/m3-micrograms per cubic meter
EMEG/MRL - ATSDR Intermediate Environmental Media Evaluation Guide/Minimal Risk Level;
CREG - Cancer Risk Evaluation Guide
Source of data: Brown and Caldwell 1992
PATHWAY NAME
EXPOSURE PATHWAY ELEMENTS
TIME
SOURCE
ENVIRONMENTAL MEDIA
POINT OF EXPOSURE
ROUTE OF EXPOSURE
EXPOSED POPULATION
Off-Site Incidental Soil Ingestion
Contaminated On-Site Soil
Storm Water Transport of Contaminated Soil
Soil in Armstrong Trailer Park
Incidental Soil Ingestion
Approx. 150 Residents
Past
(1952 to 1994)Off-Site Inhalation
Contaminated On-Site Soil
Air
Armstrong and 441 Trailer Parks
Inhalation
Approx. 300 Residents
Past
(1952 to 1976 and during 1992)
PATHWAY NAME
POTENTIAL EXPOSURE PATHWAY ELEMENTS
TIME
SOURCE
ENVIRONMENTAL MEDIA
POINT OF EXPOSURE
ROUTE OF EXPOSURE
EXPOSED POPULATION
Off-Site Ground Water
Contaminated On-Site Soil
Ground Water
Ground Water Under Armstrong Trailer Park
Ingestion
150 Residents of Armstrong Trailer Park
Future Off-Site Surface Water
Contaminated On-Site Soil
Ground-Water Transport
Lake Fairview
Incidental Ingestion and Skin Absorption
500 Annual Recreational Users of Lake Fairview
Future
Summary of Public Comments on the Draft Public Health Assessment Report and Florida HRS Response
From February 22 to March 31, 1995, Florida HRS solicited public comment on the draft public health assessment report. On March 3, the Orange County Public Health Unit distributed flyers to the approximately 50 residences in the Armstrong Trailer Park. These flyers summarized the draft public health assessment report, solicited public comment, and announced a public meeting. In a March 9 front-page (local section) story, the Orlando Sentinel newspaper summarized the findings of the draft public health assessment and announced the public meeting. From 4:00 to 7:00 PM on March 9, Florida HRS held a public meeting in the laundry room of the Armstrong Trailer Park. At this meeting the trailer park manager/owner and 15 to 20 residents expressed a number of concerns. We also received one set of written comments during the public comment period. Following is a summary of these concerns/comments and our responses:
Comment #1 Some of the residents of the Armstrong Trailer Park were concerned they were exposure to contaminated dust during the 1992 site cleanup. They complained of B odors, skin rashes, burning eyes and noses, nausea, sore throats, and chest pains during that time.
Florida HRS Response: During the 1992 soil removal, Chevron monitored pesticides in the airborne dust along the boundary between the site and the Armstrong Trailer Park. They only found chlordane and DDD in the airborne dust. The maximum concentration of chlordane in the air during the 1992 site cleanup, however, was below the ATSDR intermediate Minimal Risk Level (ATSDR 1989a, 1992b). Although there is no ATSDR Minimal Risk Level for DDD, the maximum concentration of DDD in the air during the 1992 site cleanup was 250 times less than the EPA air unit risk for the closely related pesticide DDT (ATSDR 1989b, 1992c). Therefore, we do not expect any health effects from exposure to either chlordane or DDD-contaminated dust during the 1992 site cleanup.
The symptoms the residents complained of may, however, have been caused by solvent vapors released when Chevron removed the contaminated soil. Soil at the site is known to have been contaminated with solvents. We do not have any records, however, of air monitoring for solvents during the 1992 cleanup. Therefore, we cannot say for sure if exposure to solvent vapors caused the above symptoms.
Since clean soil and grass now cover the site, we do not expect any future exposure to contaminated dust. Since there is no air monitoring data before 1992, we do not know the public health threat from breathing contaminated dust before that time.
Comment #2 One resident of the Armstrong complained that her children continue to suffer from skin rashes, runny noses, fever, bronchitis, and other flu-like symptoms.
Florida HRS Response: Since Chevron removed contaminated soil from the site in 1992 and from the Armstrong Trailer Park in 1994, it is unlikely these illness are due to chemicals from this site.
Comment #3 Some of the residents of the Armstrong Trailer Park were concerned that fruits and vegetables grown at the trailer park were no longer safe to eat.
Florida HRS Response: Although there has been no testing of any of these fruits or vegetables, there is no indication from the existing soil and ground water monitoring data that they would be unsafe to eat.
Comment #4 Chevron observed that our draft public health assessment "sensibly" concluded that this site is unlikely to pose any significant health threat. Chevron noted the draft public health assessment reached this conclusion despite the use of may conservative assumptions. These assumptions included the use of the maximum soil and ground-water concentrations as opposed to the upper 95% confidence interval and the use of high-end estimates of the amount of soil ingested by children. Chevron also suggested giving a numerical description of the increased cancer risk in addition to the qualitative descriptors such as "low" or "moderate."
Florida HRS Response: Standard methodology for preparing public health assessments calls for the use of many conservative (health protective) assumptions. These include the use of the maximum concentrations of contaminants found in each media and the use of high-end estimates of the amount of soil ingested by children. These health protective assumptions are necessary to prevent us from failing to identify a threat to public health when one exists. When our assessment fails to identify a public health threat, as is the case at this site, then we are confident that none exists. At other sites, where our initial assessment identifies a problem, we then examine our assumptions before reaching a conclusion.
Although we use numerical models to quantitatively estimate increased rates of cancer, standard methodology for preparing public health assessments suggests a qualitative description of the results. We have found that presenting numerical estimates of the increased cancer risk is confusing to the general public. Therefore, we convert our numerical estimate of the increased cancer risk to qualitative language such as "low" or "medium" that the general public can understand.
Comment #5 Chevron suggested that since sufficient environmental data are available at this site, using a statistical representation of the data in the tables would be less misleading to the public than using the maximum concentrations.
Florida HRS Response: We agree that for soil and ground water, sufficient environmental data exist to be able to use statistical techniques to describe "central tendencies." The purpose of our assessment, however, is not to assess the severity and extent of the environmental contamination but to assess its impact on public health. Therefore, for our assessment, it is appropriate to use the maximum detected concentration to assess the public health threat, even though this may make the severity and extent of environmental contamination look worse than it is.
Comment #6 Chevron asserted it is inappropriate to apply the ATSDR Cancer Risk Evaluation Guides to assessing the short-terms inhalation exposures during the 1992 site cleanup.
Florida HRS response: In our assessment for the inhalation exposure pathway, we assume nearby residents were exposed to site-related contaminated dust for the 24 years (1952 to 1976) Chevron was in operation. Unfortunately, there is no air monitoring during that time. We assumed that they were not exposed from 1976 to 1993 when vegetation covered the unpaved portions of the site. Since the only air monitoring data we have is during the 1992 site cleanup, we agree that a short-term comparison value would be more appropriate. Therefore, we have modified Tables 6 and 10 to use the ATSDR Intermediate Environmental Media Evaluation Guide/Minimal Risk Level for chlordane (0.2 µg/m3) instead of the life-time Cancer Risk Evaluation Guide (0.003µg/m3). We could not modify the comparison value for DDD since there is no shorter-term comparison value.
Comment #7 Chevron asserted that the air monitoring data do not support the conclusion that dust generated during the 1992 site cleanup could have aggravated one nearby resident's existing emphysema condition.
Florida HRS Response: Respirable size dust can aggravate an existing case of emphysema. The
air samples taken during the 1992 site cleanup were analyzed for total suspended solids but not
for respirable size dust. The highest concentration of total suspended solids: 12.5 mg/m3 (sample
#B-04, 3/23/92) is greater than the 1993 American Conference of Governmental Industrial
Hygienist, Time Weighted Average (ACGIH TWA of) 10 mg/m3 for "nuisance particulates" but
less than the Occupational Safety and Health Administration, Permissible Exposure Level (OSHA
PEL) of 15 mg/m3 (ACGIH 1993). Unfortunately, both of these guidelines apply to work place
exposure and do not take into account sick individuals nor do they account for exposure for more
than eight hour per day. Non-workers may be more susceptible due to preexisting medical
conditions and/or longer exposure periods. Therefore, it is reasonable to expect that dust from
the 1992 site cleanup may have aggravated this nearby resident's existing emphysema condition.
