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PUBLIC HEALTH ASSESSMENT

T. H. AGRICULTURE AND NUTRITION COMPANY
FRESNO, FRESNO COUNTY, CALIFORNIA


APPENDIX A- FIGURES


Figure 1. Regional location of the THAN site.



Figure 2. THAN site and site vicinity.



Figure 3. Demolished Site Structures and Excavation Locations



Figure 4. Current Site Configuration



Figure 5. Than Site Census Tracts



Figure 6. Locations of on-site monitoring wells



Figure 7. Nearsite boring and monitoring well locations



Figure 8. Locations of off-site monitoring and domestic wells.



Figure 9. Than Site Zip Code



APPENDIX B- TABLES

TABLE 1.

The following table was not avaliable in electronic format for conversion to HTML at the time of preparation of this document. To obtain a hard copy of the document, please contact:

Agency for Toxic Substances and Disease Registry
Division of Health Assessment and Consultation
Attn: Chief, Program Evaluation, Records, and Information Services
Branch, E-56
1600 Clifton Road NE, Atlanta, Georgia 30333


TABLE 2. SUBSUBSURFACE SOIL SAMPLING AT THAN

Chemicals

Maximum
detected (ppm)
Preexcavation

Detections/
# of sample
analyses*
Depth (feet
below ground
surface)*
Maximum
detected (ppm)
Postexcavation#
Comparison value in
ppb (source)
Contaminant of
Concern
Aldrin 42.0 33/1074 4 0.8 0.04 (CREG) YES
Chloroform 1.0 33/421 2 0.25 100 (CREG)
7,000 (aEMEG)
NO
DBCP 10.0 109/889 28 9.43 1,000 (aiEMEG)
Carcinogen
NO
DDD 23,585.00 379/1057 4 1226.0 3 (CREG) YES
DDE 9122.0 500/1059 6 600.0 2 (CREG) YES
DDT 319,942.0 775/1269 4 4329.0 2 (CREG) YES
DEF 759.0 47/755 16 158.0
YES
1,2-Dichloroethane 200.0 4/422 2 200.0 8 (CREG) YES
Dieldrin 4,878.0 287/1178 4 223.0 0.04 (CREG)
40L (aEMEG)
YES
Dimethoate 1.0 4/805 5 <0.05 100 (aRMEG) NO
Dinoseb 5,200.0 26/280 6 41.0 700 (aRMEG) NO
Diphenamid 15,095.0 65/899 2 9715.0 20,000 (aRMEG) NO
Guthion 160.0 7/780 16 81.5
NO
-HCH 684.0 61/1184 5 40.0 0.1 (CREG) YES
-HCH 190.0 68/1112 2 1.0 0.4 (CREG)
400 (aiEMEG)
YES
-HCH 143.6 23/958 2 30.0
YES
Lindane 4,070.0 92/1066 5 80.0 200 (aRMEG) YES
Parathion 22,262.0 161/946 6 126.0 Carcinogen YES
Toxaphene 7,900.0 245/1117 1 7,900.0 0.6 (CREG)
40 (aiEMEG)
10,000 (aRMEG)
YES
Trifluralin 316.0 139/733 1 188.0 90 (CREG)
5,000 (aRMEG)
YES

*Data from Table 5-8 of the Remedial Investigation Report (1).
#Data from Table 5-9 of the Remedial Investigation Report (1).


TABLE 3. ON-SITE GROUNDWATER CONTAMINATION DETECTED IN THE MONITORING WELLS ON THE THAN SITE

Chemicals

Maximum
concentration
(ppb)#

Aqufier zone
(Well identity)#
Comparison value in ppb
(source)
Contaminant of Concern
Aldrin <0.05
<0.05
<0.05
A
B
C
0.002 (CREG)
0.3 (cEMEG)
NO
Chloroform 16,667.0
18.0
<0.05
A (77)
B (155B0)
C
6 (CREG)
0.6 (cREMG)
2 (aEMEG)
YES
DBCP 61.0
1.28
2.50
A (2)
B (155B0)
C (155C1)
0.2 (MCL) YES
DDD 0.66
<0.05
<0.05
A (145)
B
C
0.1 (CREG) YES
DDE <0.05
<0.05
<0.05
A
B
C
0.1 (CREG) NO
DDT 0.16
<0.05
<0.05
A (2)
B
C
0.1 (CREG)
5 (cRMEG)
20 (aRMEG)
YES
DEF 0.38
<0.05
<0.05
A (140)
B
C

YES
1,2-Dichloroethane 63.6
<0.05
<0.05
A (139)
B
C
0.4 (CREG) YES
Dieldrin 12.8
<0.05
<0.05
A (6)
B
C
0.002 (CREG)
0.5 (cEMEG)
2 (aEMEG)
YES
Dimethoate 0.48
<0.05
<0.05
A (2)
B
C
2 (cRMEG)
7 (aRMEG)
NO
Dinoseb 474.4
<1
<1
A (140)
B
C
10 (cRMEG)
40 (aRMEG)
YES
Diphenamid 7,266.6
<1
<1
A (3)
B
C
300 (cRMEG)
1,000 (aRMEG)
YES
Guthion nm
nm
nm
A
B
C

NO
-HCH 3.3
<0.05
<0.05
A (77)
B
C
0.006 (CREG) YES
-HCH 23.6
<0.05
<0.05
A (139)
B
C
0.02 (CREG)
5 (cEMEG)
20 (aEMEG)
YES
-HCH 12.0
<0.05
<0.05
A (77)
B
C
0.2 (MCL) YES
Lindane 6.0
<0.05
<0.05
A (6)
B
C
0.2 (LTHA)
3 (cRMEG)
10 (aRMEG)
YES
Parathion 0.84
<0.05
<0.05
A (2)
B
C
30 (CA AL) NO
Toxaphene <0.05
<1
<0.05
A
B
C
0.03 (CREG)
0.5 (ciEMEG)
2 (aiEMEG)
NO
Trifluralin 0.65
<0.05
<0.05
A (77)
B
C
5 (CREG)
80 (cRMEG)
300 (aRMEG)
NO

#DATA FROM APPENDIX H IN THE REMEDIAL INVESTIGATION (1)
nm=not measured


TABLE 4. SUBSURFACE SOIL CONTAMINATION IN THE OFF-SITE AREA, THE THAN-OWNED ORCHARD

Chemicals Maximum
concentration
(ppm)*
Detections/# of
sample
ananlyses
Comparison value in ppm
(source)
Contaminant of
Concern
Aldrin <0.05 0/65 0.04 (CREG) NO
Chloroform <0.6 0/42 100 (CREG) NO
DBCP <0.01 0/70
NO
DDD 0.46 1/65 3 (CREG) NO
DDE 0.23 5/65 2 (CREG) NO
DDT 0.48 6/65 2 (CREG) NO
DEF <0.05 0/56
NO
1,2-Dichloroethane <0.6 0/15 8 (CREG) NO
Dieldrin 0.41 10/65 0.04 (CREG) YES
Dimethoate <0.05 0/56 0.4 (picaREMEG) NO
Dinoseb <0.05 0/56 700 (aRMEG) NO
Diphenamid <1.0 0/56 60 (picaRMEG) NO
Guthion <0.5 0/56
NO
-HCH <0.05 0/65 0.1 (CREG) NO
-HCH <0.05 0/65 0.4 (CREG) NO
-HCH <0.05 0/65 0.2 (CREG) NO
Lindane <0.05 0/65 0.6 (picaRMEG) NO
Parathion <0.05 0/56
NO
Toxaphene 0.92 6/65 0.6 (CREG) YES
Trifluralin <0.05 0/56 20 (picaRMEG) NO

*DATA FROM APPENDIX G IN THE REMEDIAL INVESTIGATION (1)


TABLE 5. OFF-SITE GROUNDWATER CONTAMINATION DETECTED IN THE MONITORING WELLS NEAR THE THAN SITE

Chemical Maximum down
gradient
concentration
(ppb)#
Aquifer zone (well
identity)#
Maximum
upgradient
concentration
(ppb)#
Comparison value
in ppb
(source)
Contaminant
of Concern
Aldrin <0.05
<0.05
0.09
<0.05
A
B
C (154C1)
D
0.18
<0.05
<0.05
na
0.002 (CREG)
0.3 (cEMEG)
YES
Chloroform 1,450.0
160.0
7.0
<0.5
A (31A)
B (182B1)
C (182C1)
D
0.37
<0.5
<0.5
na
6 (CREG)
0.6 (cRMEG)
2 (aEMEG)
YES
DBCP 1.16
5.70
5.60
0.22
A (31A)
B (153B1)
C (153C1)
D (181D1)
5.20
0.46
0.45
na
0.2 (MCL) YES
DDD <0.05
<0.05
<0.05
<0.05
A
B
C
D
0.37
<0.5
<0.5
na
0.1 (CREG) NO
DDE <0.05
<0.05
<0.05
<0.05
A
B
C
D
5.20
0.46
0.45
na
0.1 (CREG) NO
DDT <0.05
<0.05
<0.05
<0.05
A
B
C
D
<0.5
<0.5
<0.5
na
0.1 (CREG)
5(cRMEG)
20(aRMEG)
NO
DEF <0.05
<0.05
<0.05
<0.05
A
B
C
D
0.11
<0.5
<0.5
na

NO
1,2-Dichlorethane 1.9
2.2
1.2
<0.5
A (31A)
B (183B2)
C (153C1)
D
<0.5
<0.5
<0.5
na
0.4 (CREG) YES
Dieldrin 0.82
1.1
<0.05
<0.05
A (30A)
B (153B1)
C
D
0.10
<0.05
<0.05
na
0.002 (CREG)
0.5 (cEMEG)
2 (aEMEG)
YES
Dimethoate <0.05
<0.05
<0.05
<0.05
A
B
C
D
0.37
<0.5
<0.5
na
2 (cRMEG)
7 (aRMEG)
NO
Dinoseb 1.1
7.68
4.15
<1
A (30A)
B (153B1)
C (150C1)
D
5.20
0.46
0.45
na
10 (cRMEG)
40 (aRMEG)
NO
Diphenamid <1
<1
<1
<1
A
B
C
D
<0.5
<0.5
<0.5
na
300 (cRMEG
1,000 (aRMEG)
NO
Guthion nm
nm
nm
nm
A
B
C
D
0.11
<0.05
<0.05
NA

NO
-HCH 8.2
8.8
<0.05
<0.05
A (29A)
B (29B)
C
D
8.2
8.8
<0.05
na
0.006 (CREG) YES
-HCH 1.6
0.23
<0.05
<0.05
A (30A)
B (31B)
C
D
0.37
<0.5
<0.5
na
0.02 (CREG)
5 (cEMEG)
20 (aEMEG)
YES
-HCH 0.82
0.03
<0.05
<0.05
A (30A)
B (31B)
C
D
0.10
<0.05
<0.05
na
0.2 (MCL) YES
Lindane 0.47
0.09
<0.05
<0.05
A (31A)
B (153B1)
C
D
0.16
<0.05
<0.05
na
0.2 (LTHA)
3 (cRMEG)
10 (aRMEG)
YES
Parathion <0.05
<0.05
<0.05
<0.05
A
B
C
D
0.11
<0.05
<0.05
na

NO
Toxaphene <0.05
<0.05
<0.05
<0.05
A
B
C
D
0.10
<0.05
<0.05
0.03 (CREG)
0.5 (ciEMEG)
2 (aiEMEG)
NO
Trifluralin nm
0.50
0.93
<0.05
A
B (154B1)
C (154C1)
D
5.20
0.46
0.45
na
5 (CREG)
80 (cRMEG)
300 (aRMEG)
NO

#DATA FROM APPENDIX H IN THE REMEDIAL INVESTIGATION (1).
na=not available because there is no upgradient well that screens the D-aquifer.
nm-not measured


TABLE 6. GROUNDWATER DATA FROM PRIVATE WELLS ON OR NEAR THE THAN SITE

Chemicals Maximum
upgradient
concentration
(ppb)#
Maximum
THAN-well*
concentration
(ppb)
Maximum
downgradient
concentration
(ppb)#
Comparison
value in ppb
(source)
Contaminant
of Concern
Aldrin <0.05 <0.05 0.02 0.002 (CREG) YES
Chloroform 0.06 <0.05 175 6 (CREG)
0.6 (cRMEG)
2 (aEMEG)
YES
DBCP 8.41 2.20 9.06 0.2 (MCL) YES
DDD <0.05 <0.05 0.02 0.1 (CREG) NO
DDE <0.05 0.07 <0.05 0.1 (CREG) NO
DDT <0.05 0.09 0.09 0.1 (CREG)
5 (cRMEG)
20 (aRMEG)
NO
DEF nm <0.05 nm
NO
1,2-Dichloroethane <0.5 <0.50 6.35 0.4 (CREG) YES
Dieldrin <0.05 0.23 0.38 0.002 (CREG)
0.5 (cEMEG)
2 (aEMEG)
YES
Dimethoate nm nm nm 2 (cRMEG)
7 (aRMEG)
NO
Dinoseb nm <1 nm 10 (cRMEG)
40 (aRMEG)
NO
Diphenamid nm <1 nm 300 (cRMEG)
1,000(aRMEG)
NO
Guthion nm <0.05 nm
NO
-HCH <0.05 <0.05 0.18 0.006 CREG) YES
-HCH <0.05 <0.05 <0.05 0.02 (CREG)
5 (cEMEG)
20 (aEMEG)
NO
-HCH <0.05 <0.05 0.07 0.2 (MCL) NO
Lindane <0.05 <0.05 0.33 0.2 (LTHA)
3 (cRMEG)
10 (aRMEG)
YES
Nitrate 54,000 58,900 89,170 10,000 (MCL) YES
Parathion nm <0.05 nm 30 (CA AL) NO
Toxaphene <0.05 0.2 <0.05 0.03 (CREG)
0.5 (ciEMEG)
2 (aiEMEG)
NO
Trifluralin 0.2 <0.05 nm 5 (CREG)
80 (cRMEG)
300 (aRMEG)
NO

#DATA FROM APPENDIX H IN THE REMEDIAL INVESTIGATION (1) AND STATE MEMORANDUMS.
nm=not measured
*Data from THAN-owned well #904 located on the site.


TABLE 7. COMPLETED EXPOSURE PATHWAYS AT THE THAN SITE

SOURCE ENVIRONMENTAL
MEDIA
POINT OF EXPOSURE ROUTE OF
EXPOSURE
EXPOSED
POPULATION
TIME
THAN and other nearby nonpoint sources Groundwater Persons who had a private well
for domestic purposes and now
have municipal water service
Dermal contact
Ingestion Inhalation
Residents
Off-site workers
Schoolchildren from
Temperance-Kutner School
On-site workers
Past
THAN and other nearby nonpoint sources Groundwater Persons who use a private well for domestic purposes Dermal contact
Ingestion Inhalation
Residents
Off-site workers
Past Present
Future
THAN Air Residents living nearby the THAN site Inhalation Dermal
contact
Residents Past
THAN Air On-site especially near truck routes and in and around process areas Inhalation Dermal
contact
On-site workers not wearing adequate respiratory protection Past
THAN Surface soil Unpaved areas of site Dermal contact
Ingestion
On-site workers not wearing
adequate protective clothing
Past



TABLE 8. POTENTIAL EXPOSURE PATHWAYS AT THE THAN SITE

SOURCE ENVIRONMENTAL MEDIA POINT OF EXPOSURE ROUTE OF EXPOSURE EXPOSED POPULATION TIME
THAN Surface soil Unpaved areas
off-site
Dermal contact
Ingestion
Residents
Off-site workers
Past
Present
Future



TABLE 9. EXPOSURE ASSUMPTIONS USED FOR TOXICOLOGICAL EVALUATION
AT THE THAN SITE

SYMBOL DESCRIPTION (UNITS) VALUE
IRadult & on-site worker, water Water Ingestion Rate, adult and on-site worker
(liters/day)
2
IRoff--site worker, water Water Ingestion Rate, off-site worker (liters/day) 1
IRon-site worker, air Inhalation Rate, worker (m3/8hr workday) 9.6
BWadult Body Weight, adult (kg) 70
EFresident Exposure Frequency, resident (days per year) 365
EFworker Exposure Frequency, worker (days per year) 250
EDadult, city water, inhalation Exposure Duration for inhalation, adult resident now using city water (years) 11
EDadult, city water, ingestion Exposure Duration for ingestion, adult resident and off-site worker now using city water (years) 9
EDadult, well Exposure Duration, adult resident still using well water (years) 38
EDon-site workers, water Exposure Duration for water exposure, on-site worker (years) 3
EDon-site workers, air Exposure Duration for air exposure, on-site worker (years) 22



TABLE 10. Frequency distribution of types of cancers diagnosed 1988-1991 (63). A comparison of census tracts 58 and 5901 with Fresno county as a whole:

Site of Cancer Tracts 58, 5901 Fresno County
Buccal 10(5.5%) 195(2.4%)
Digestive 24(13.2) 1519(18.7)
Respiratory 26(14.3) 1238(15.2)
Soft tissue 2(1.1) 45(.5)
Skin 10(5.5) 303(3.7)
Breast 25(13.7) 1210(14.9)
Female genital 10(5.5) 534(6.6)
Male genital 31(17.0) 1440(17.7)
Urinary 12(6.6) 431(5.3)
Brain 4(2.2) 132(2.2)
Leukemia 7(3.8) 226(2.8)
Lymphomas 10(5.5) 368(4.5)
All others 11(6.0) 479(5.9)



APPENDIX C- RESPONSE TO PUBLIC COMMENT

CDHS received four letters during the public comment period which occurred from January 19, 1994 to March 10, 1995. Two letters came from community members and they made comments about the health assessment as a whole. Their letters will be presented in their entirety. Comments were also received from the California Department of Toxic Substances Control and T.H. Agriculture and Nutrition Company, Inc. Some of their comments were editorial in nature and when appropriate these comments were incorporated into the health assessment. Their other comments will be addressed in this appendix.

Comments from a resident who had resided beside the THAN site since the 1950s: "There were several things that were good about the THAN Public Health Assessment, but I still think you are selling us short. That is those of us that have lived here a long time especially.

I have lived here at this chemical site for forty years. Nobody can understand what we went through unless you lived here. You wouldn't think a human being would treat another human being like we were treated and the amount of chemicals that we breathed, drank, bathed in, and what our bodies were continually exposed to.

On one occasion, I was standing in the middle of our yard and I was sprayed full blast with the chemicals that they were spraying the almond trees with. All I could do was close my eyes and try to turn my head away. I was trying to get the man to turn the spray rig around before he got to our yard, but he didn't and sprayed me full blast.

Our house, garden and yard were sprayed every time they sprayed the almond orchard. This spray would go all the way through our breezeway, all over our yard and garden. They knew there were little children that would be playing in that yard, but yet they sprayed it every time they sprayed the almond orchard.

One time they sprayed and my husband's car was sitting at the end of the house. When he started to go to work he called me to come look. This gook they were spraying was all over his car windows and windshield. It was all green and oily. He had to get warm soapy water to wash it off before he could see to drive to work.

They were bound to have been using this orchard for a test plot. They sprayed two or three times more than others did their trees around us. There were times when all our place was sprayed with the spray that after they finished spraying there were skull and crossbones signs put on the trees along the edge of the orchard. So whatever that spray was- all our place was sprayed with it. Yes, and all the play area these small children had to play in was sprayed with it, too.

Then you tell us were not exposed to all that much.

I'm sure a lot of those chemicals could be lots more deadly mixed together.

The man that was in charge up there stopped by our house right after they stopped working up there. He wanted to know if we had seen or heard anyone up at the plant during the weekend. We said "No". If we had we would have thought it just some of their men working up there. He said that someone had gotten into the old big warehouse and had a hey day driving and playing with the loaders. He said, "There are chemicals up there if you put your hand in up to your elbow, it would kill you". Now don't you think that is pretty dangerous stuff for us in the neighborhood to be breathing and our skin and bodies exposed to as well as it settling on our garden, on our vegetables to eat and the childrens' play area.

We were exposed to Lord only knows what every day of our lives and still are. Then you say we weren't exposed all that much. Don't tell it to me. I know better.

The Health Department kept telling us not to worry. Just look what has happened to us from them not listening to what we were telling them. We feel you are doing the same thing.

We spent thousands and thousands of dollars on doctor bills and still are.

Is it any wonder that my 37-year old daughter hasn't been able to get pregnant. She was born and grew up here. Our property joins the chemical plant, remember? Don't tell me it isn't likely to have had that much effect on us. By all means listen to what people are telling you.

All those chemicals were blown out daily into the air. There was no way you could escape being exposed to them for it was just like yellowish cream colored cloud-like fog, the people in cars would turn their lights on many times to drive through hoping the on-coming traffic would see their lights and not run into them. This settled over the neighborhood. This cloud would smother you. You couldn't breathe right.

They also burned their empty containers and we would have to close our windows and doors and turn off our cooler, no matter how hot the day, as the smoke was horrible. It would burn our throats and nose until we would have sore throats next day. Yet, there were warnings on their containers you would buy, "Dangerous, do not burn containers and inhale the fumes".

Think about all the poisoned water we drank and used in our food, bathed in it, breathed the steam from it while showering. We watered our gardens with it. Every minute we were around our homes, we were bombarded with chemicals in many deadly forms all the time.

We are thinking we should sue the health department. They let us down but good and look what happened because they didn't listen when we were begging them to help us. It's just inhumane to go through what we had to go through. Please think long and hard about this.

Believe me we have needed help for forty years and forty years we have been let down. If someone had listened forty years ago this mess wouldn't have happened.

I still think a health survey should be done now to catch all the people that were children then. Their stories are definitely not good.

Keep these things in mind while you are making your decisions about our future and the future of our children and grandchildren."

Comments from the Co-Chairman of the TK Neighbors in Action neighborhood group:
It is extremely important to note that this was a health assessment or health survey- not a full-blown health study. We, TK Neighbors in Action, were repeatedly told by the California Department of Health Services that our population sample was too small to be statistically significant for a health study. Unfortunately, there is a lot more illness and cancer and lupus than this "survey" indicates.

There is so much that we don't know what the toxic contaminants to which the residents of this area were exposed. We are just on the "leading edge" in this area. We have no idea what are the synergistic effects of these toxins acting together. We have no idea how much exposure, of for how long in duration our residents were "at risk". We know, only superficially, that exposure to toxic pesticides and carcinogens weakens the immune system. I believe that there are many long-time residents whose immune systems have been weakened and even altered- but to what extent? I have friends and neighbors who have died or are dying of cancer, lupus, emphysema. I know others with severe tachycardia, severe headaches, and severe asthma.

I firmly agree that educating the physicians of the residents in this area is a must. There is a tremendous gap of information on behalf of the physicians. They need practical knowledge and practical awareness of the toxins and the exposure which, in many cases, lasted decades.

I also firmly believe that a registry needs to be set-up just for this area. I am praying that this will be organized and put into action. We need to document the illness and health problems in this area. We need to document the results or after-effects of a weakened immune system. We need to carry this into the next generation because many of the children living in this area during the worst exposures are now adults and may have detrimental health effects.

DTSC had many editorial comments some of which were addressed, others are inappropriate for a health assessment in contrast with a risk assessment, and others which have been addressed below.

DTSC comment: Surface soil was defined as the top 3 inches. Only 3 samples were reported as having been collected at depths of 3 inches or less with DDT and its isomers being the only contaminants identified. Many contaminants of concern were identified in subsurface (depths greater than 3 inches or 0-12 inch composite samples), but subsurface soil data were not used in the evaluation. Statements are made that if surface soils are contaminated to a similar extent, exposures to these contaminants of concern may have occurred. However, since surface soil data are inadequate to evaluate exposure, risks for these contaminants of concern were not evaluated. We recommend using data from composite samples down to 12 inches, for both on-site and off-site evaluations when 0-3 inch data are inadequate, to provide some estimates for risk of these contaminants of concern. Of particular concern is the carcinogen toxaphene identified as a contaminant of concern in subsurface soils both on- and off-site that was identified to have risks of 2.4 x 10- 4 in the July 1993 baseline human health risk assessment submitted to DTSC as part of the remedial investigation process.

CDHS response: While we are comfortable stating that exposure may have occurred, we are not comfortable calculating doses using subsurface soil data for surface soil exposure. We agree over concern for toxaphene exposure; however we do not agree that using current mixed-subsurface data would be useful in evaluating past exposures to on-site workers. A dose could be calculated but interpretation of this dose would have many more uncertainties than are typically inherent in such an approach.

DTSC comment: The contradictory results on variation in susceptibility to DBCP-induced testicular toxicity between sexually mature and immature rats may be due to variation in dose levels or endpoints assessed, because immature rats do not possess the full complement of spermatogenic cells present in sexually mature rats and the degenerative testicular effect of DBCP is reduction in spermatogenic cells. Have the original citations been evaluated to establish whether these results are actually contradictory?

CDHS response: Very good point and no, for the purposes of this health assessment, we did not review the original citations.

DTSC comment: We recommend using surrogate toxicity data or extrapolation of toxicity values, as it common for U.S. EPA superfund risk assessments, to provide a more comprehensive evaluation of the estimated hazards to people on or near the THAN site. If there is no ATSDR non-cancer health comparison value and no RfD (as with 1,2-dichloroethane), we suggest you consider using a surrogate approach. Also, subchronic or oral RfDs in IRIS could be used to extrapolate to chronic and inhalation RfDs, respectively. For example, IRIS does contain a subchronic inhalation RfD for DBCP which could be extrapolated to obtain a chronic inhalation RfD. IRIS also contains a subchronic oral RfD for lindane that could be extrapolated to a chronic RfD. The oral RfD for dimethoate may be extrapolated to an inhalation RfD. A toxaphene RfD of 2.5E-04 mg/kg/day (based on liver effects) has been published in the U.S. EPA Office of Pesticides Programs Reference Dose Tracking Report. Incorporation of these toxicity criteria would allow more comprehensive evaluation of human health hazards related to the site.

CDHS response: CDHS agrees that this approach could have been taken. Because the receptor population, the workers who worked at the facility, can not be identified for follow-up, this pathway was not further developed.

THAN submitted comments during the public comment period and asked that comments they had submitted regarding the health assessment summary fact sheet also be addressed.

Several of THAN's comments regarded the inclusion of other companies in the ownership of and contribution to the contamination on the property. CDHS did attempt to make this clearer in the health assessment; it is not the purpose of the health assessment to assign blame for the contamination. However, it should be noted that the other companies operated there from 1951 to 1959, a period of eight years, while THAN owned and operated the site from 1959 until operations were discontinued there in 1981, a period of 22 years. The site was called the THAN site when it was nominated to the NPL list and thus we referred to the site that way in the health assessment.

THAN comment: According to ATSDR's Public Health Guidance Manual, "the unverified, ancedotal reports of residents' experiences are inappropriate for inclusion in the health assessment report. Relevant guidance states that the health assessor may interview residents and community groups to obtain exposure related information, but the assessor should remember that their perspectives on risk and judgements may be personal. While identifying the community health concerns, the assessor should review the exposure related information obtained from residents for the purpose of clearly and concisely stating the issues that the community would like addressed by the health assessment. The assessor should then use the pathways analysis and toxicological information to determine whether the concerns expressed by the community are plausible."

CDHS response: CDHS appreciates that THAN reviewed the guidance that ATSDR has set forth for health assessent reports. CDHS staff did feel that the community health concerns section for this site was particularly important given the long history of residing next to the site for most of these neighbors, the lack of environmental information that is available to evaluate past exposure, and the tremendous health concern that exists in the community. CDHS understands that the community members may have a particular perspective just as a responsible party may have a particular perspective. CDHS did address the community health concerns in the the community health concerns evaluation section using pathways analysis and toxicological information.

ATSDR has reviewed and endorses the health assessment as it has been written. Additionally, it should be noted that the material that THAN cites is "guidance" and not "policy".

THAN comment: Truck trailors used to transport excavated soil off-site were lined, tarped, and decontaminated before leaving the site. This information is documented in reports prepared by THAN's consultants.

CDHS response: The reference to the uncovered trucks is made in the community health concerns section where we were recording the recollections of the residents.

THAN comment: Although the health assessment report recognizes that groundwater in the area may be contaminated as a result of agricultural practices the draft report does not provide a comparison of site-related groundwater data with background concentration of the contaminants, as required according to the Public Health Assessment Guidance Manual.

CDHS rsponse: While this information may not specifically be noted in the text, please note the background or upgradient concentrations that were and are listed for monitoring wells (Table 5) and private wells (Table 6).

THAN comment: Why is it assumed for DBCP and for other chemicals that the groundwater was first contaminated in 1979. Has the author concluded that chloroform is an indicator of THAN contamination emanating from the THAN site? Was modeling performed by DHS, or is DHS referring to the modeling performed by THAN's consultants? The groundwater simulation modeling performed by THAN's consultants (and documented in Appendix R of the RI Report) was for the purposes of estimating certain bulk hydrodynamic characteristics of the groundwater flow system affected by chemicals associated with the site and evaluation of the time during which releases of chloroform may have occurred. To the extent that the DHS/ATSDR relies on the results of the modeling as the basis for the conclusion that "... groundwater first became contaminated with DBCP from the THAN site in 1979", that conclusion is completely without foundation and should be removed from the document unless supporting justification can be provided.

First, it cannot be shown that off-site groundwater was in fact "contaminated" with DBCP as a result of THAN's activities on-site. It is entirely possible, for example, that the DBCP which affected THAN's supply well on-site originated from the same source as the DBCP which resulted in a concentration of 7.27 micrograms per liter in the February 1983 sample from well #938, located approximately 1,200 feet north and 3,700 feet west of the site-- an area of groundwater clearly unaffected by potential on-site sources of chemicals. Second, the areas on-site which constitute potential sources of DBCP to groundwater differ in large part from those identified as potential sources of chloroform. Therefore, the entire chemical fate and hydrodynamic regime which would govern the movement of DBCP from such potential sources into off-site groundwater likely differs significantly from that which governed the movement of chloroform.

Finally, as noted in the sensitivity analysis portion of Appendix R to the RI Report, a range of average velocities for groundwater affected by chloroform were identified by the simulations performed. The actual time of first chloroform release consistent with the model used could have been significantly (approximately 30 years) earlier than estimated by the DHS.

If modeling was performed by DHS, then this section should be expanded to provide detail regarding the methodology and assumptions utilized.

CDHS response: CDHS does not have groundwater modellers at its disposal. Rather than arbitrarily guessing the time during which the groundwater may have first become contaminated with the many compounds which have been found in the groundwater, CDHS did rely on the groundwater model that was developed for THAN by its contractors. We acknowledge that the model which used chloroform to study the bulk hydrodynamic characteristics of the groundwater flow system, was not being developed to evaluate point estimates of exposure at private wells. However, lacking better information, we do think it is acceptable to use the information in this way with qualifiers that the exposure estimate has uncertainty associated with it. We do not think that THAN has provided any compeling reason why this is an inappropriate use of the models output. Likewise, we also used this same exposure estimate for other chemicals in the groundwater, again with the understanding that other types of chemicals may be transported differently in the vadose zone and groundwater, but this is a crude estimate of the possible exposure period.

As for the DBCP issue, it is not CDHS's or ATSDR's role to determine the source of the DBCP in the groundwater; however, according to DTSC, THAN has been identified as adding to the "area-wide, non-point" source problem.

CDHS used 1979 as the first year of off-site migration of the contamination in the groundwater; according to the model this is a reasonable estimate of the spread of contamination. This also reasonably coincides with the groundwater sampling of the private wells that was conducted by CDHS in 1981. CDHS does acknowledge that the exact length of time during which exposure actually occurred is unknown and certainly could have been longer.

THAN comment: Carbon tetrachloride may have inadvertently been omitted from this discussion. (The discussion the comment was referring to concerns the chemicals residents who previously had used private well for drinking water and are currently using municipal water)

CDHS response: CDHS is not aware of groundwater data that shows the private well water has been contaminated with carbon tetrachloride. We depended primarily on the information in Appendix H of the RI Report that was developed by contractors for THAN.

THAN comment: It is not clear why "on-site workers with inadequate protection" are selected as a separate population for evaluation. Any evaluation of exposure is purely speculative given the fact that it is impossible to recreate exposure incidents or to determine the frequency and duration of such exposures. More importantly, such exposure evaluations provide no useful information regarding the current and future impact of the site on public health.

CDHS response: It is important, and CDHS believes useful, to discuss all completed, potential, and even eliminated pathways of exposure in the health assessment so that the reader understands that the whole picture has been evaluated. The OSHA inspectors found problems which leads one to suspect that this exposure pathway did exist. It certainly would be preferable to have more information so that we could more definitively examine this pathway.

THAN comment: The authors note that the existence of only three samples at the 0 to 3 inches bgs depth prevents a complete evaluation of the exposure of on-site workers to surface soils. Because the site has undergone extensive remediation and excavation since its days as an operating facility, no amount of sampling could be done now to develop an estimate of the past soil concentrations.

CDHS response: CDHS agrees that in light of the remediation and harrowing that has occurred at the site, surface soil sampling will not provide any useful information for evaluating past exposures. Hence, we have not recommended that on-site surface soil should be conducted. However, as part of the exposure pathway analysis, it is the obligation of the health assessor to describe the various elements of the pathway. In the case of the "surface soil exposure to on-site worker" pathway, the level of contamination is not known because there is insufficient surface soil data to evaluate it.

THAN comment: It has been determined by the Department of Toxic Substances Control that sufficient data exist to proceed with the preparation of the RI and FS reports. DHS should consider the use of other samples collected on and off-site as representative of surface soil due to the extent of soil mixing that has occurred as a result of grading, discoing, and vehicular traffic activities. For further discussion regarding the evaluation of surface soil exposure please consult with THAN's Multipathway Health Risk Assessment.

CDHS response: According to ATSDR's Public Health Assessment Guidance Manual, surface soil means the first three inches. CDHS does understand that the first three inches of the soil has been disturbed. Unlike THAN's Multipathway Health Risk Assesment which evaluates current and future exposures to the soil, the use of the "mixed" soil levels for past exposures does not seem as valid. In addition to lacking good information about the level of contamination, the definition of this pathway also lacks good understanding of the receptor population and what exposure parameters are appropriate.

THAN comment: The exposure evaluation of nearby resident and off-site workers presented in the toxicological evaluation section is based on the assumption that DEF and the much smaller, more volatile chemical, butyl mercaptan, will be found in the air away from the site in the same proportion (i.e., 20:1) as they are present in the original product. This assumption is incorrect. Because of this lower tendency to volatize, the larger chemical, DEF, will be present in air above the product in a much smaller ratio of DEF to butyl mercaptan than the ratio in the original product. Thus, there is no basis to conclude that people who could smell something were exposed to a concentration of 20ppb, or any other concentration, of DEF. In addition, there is no statement regarding the assumed duration and frequency of exposure, factors which must also be taken into account to evaluate the likelihood of an adverse health effect.

CDHS response: CDHS agrees with the logic about the actual concentrations that may have existed in the air above the product. In lieu of actual data, the worst case scenario was described. No doses were calculated since no exposure assumptions were developed for this pathway.

THAN comment: The assumption that nearby residents and off-site workers who smelled something were exposed to at least the odor threshold concentration of 1.06ppb of dimethoate is not supportable. The conclusion that people were exposed to concentrations much higher even than 1.06ppb, based on reports that they altered their lifestyle has even less basis. It is possible that one or more additional chemicals, particularly the reduced mercaptans associated with DEF, were causing or contributing to the odor. Consider, for example, the 1981 air monitoring results from the Fresno County Department of Health that were described in the Environmental Contamination Section of the report. On a day reported to have "strong" downwind odors of a "skunkish" nature, the health department analyzed the air samples for dimethoate and reported that detectable levels were not present. While the detection limit (1,7 ppb) was above the odor threshold (1.06ppb), it was close enough to the threshold concentration to believe that the reports of a strong odor could not have been attributed to dimethoate. This would be particularly true if the intensity of an odor is proportional to the concentration of the odorant, as you state in the health assessment.

CDHS response: As THAN is aware, there was inadequate air monitoring conducted to fully understand what exposures to the nearby community may have occurred when the facility was in operation. In lieu of actual data, the worst case scenario was described. No doses were calculated since no exposure assumptions were developed for this pathway.

THAN comment: Given that 1,2-dichloroethane does not appear on THAN's inventory may reasonably suggest that it is present in site soils and groundwater as a result of responsible parties other than THAN.

CHDS response: This may be so; however, it is not part of the responsibility of the health assessor to assign blame for the contamination.

THAN comment: The report includes a statement to the effect that odor-related health effects should not be simply dismissed as unexpected based on toxicology or should not be dismissed as being psychological in origin. The report also needs to acknowledge and state that chemical's can be present at levels above their odor threshold without necessarily being present at levels that cause adverse health effects. Available data suggest that may in fact be the case for mercaptans.

CDHS response: CDHS agrees that this may be so, but the exact chemicals that the community may have smelled are unknown and there is a dearth of toxicological information about the mercaptans as well as DEF and dimethoate.

THAN comment: What is the basis for the statement that "THAN has reported that the well was not used for drinking water purposes"? What is the basis for the statement "...according to THAN, site operations ceased in the late afternoon and no mixing occurred on the weekends"?

CDHS response: CDHS asked the project manager from DTSC these questions and these are the responses that he gave us. Our understanding was that he got these answers by speaking with knowledgeable people at THAN. We have added a reference in the text citing the source for these two pieces of information.

THAN comment: The health assessment of the THAN site deviated from ATSDR's guidelines by focusing on the hazards posed by the site in the past and by not presenting a conclusion about the site as it exists today. While at least some members of the community are concerned about emissions and perhaps even workplace hazards posed by the former operating facility, they are undoubtedly concerned about the current site.

CDHS comment: As documented in the community concerns section, the residents living near THAN are primarily concerned about the health effects they used to experience when the facility was in operation, the health effects they are currently experiencing, and the health effects they are worried may develop because of living next to the THAN site. In order to address these concerns, it was necessary to evaluate past and current exposures. CDHS has tried to accurately depict the current and past conditions and the conclusion section does reflect the fact that all of the completed pathways existed in the past but do not currently exist. In the conclusion section CDHS does summarize an exposure pathways that currently exists; however,this pathway involves contaminated groundwater usage where the contamination is due to non-point area sources and not THAN.

THAN comment: The conclusion that the operating facility "likely posed a public health hazard to nearby residents that inhaled air emissions from the site..." is much stronger than is warranted by the evaluations regarding exposure and toxicity presented earlier in the report. For example, the report states that "the scarcity of air data made it impossible to estimate the exposure...". The report states "..we have inadequate knowledge about the health effects that might result from long-term, low-level exposure to any one of the compounds". The conclusion appears to be based on the previous odor complaint, even though public health officials at the time of the most serious odor complaints apparently did not believe that the levels were sufficiently high to cause adverse health effects.

CDHS response: The conclusion is based on anecdotal evidence from residents rather than actual air monitoring data and good toxicological information. The air district did believe that exposure was probably occurring and ordered THAN to discontinue using the smelly chemicals.

THAN comment (submitted during THAN's review of the fact sheet): As a general matter, we have serious concerns about the inclusion of speculations concerning the risks that may have been posed in the past by historical formulation plant operations at the site. The assessment of risks that may have existed in the past is beyond the scope of the health assessment authorized for National Priority List ("NPL") sites under Section 104 of the Comprehensive Environmental Response Compensation and Liability Act ("CERCLA") as amended in 1986 by the Superfund Reauthorization and Amendments Act ("SARA"). Pursuant to Section 104(I)(6), 42 U.S.C. $9604 (I)(6), ATSDR shall perform a health assessment for each facility on the NPL. The term "health assessments of the potential risk to human health posed by individual sites and facilities, based on such factors as the nature and extent of contamination, the existence of potential pathways of human exposure (including ground or surface water contamination, air emissions, and food chain contamination), the size and potential susceptibility of the community within the likely pathways of exposure, the comparison of expected human exposure levels to the short term and long term health effects associated with identified hazardous substances and any available recommended exposure or tolerance limits for such hazardous substances, and the comparison of exisiting morbidity and mortaility data on diseases that may be associated with the observed levels of exposure.

The term health assessment is defined in terms of present site conditions and the potential risks posed to human health by present site conditions. Moreover, CERCLA expressly provides that "[t]he purpose of health assessments under [CERCLA] shall be to assist in determining whether actions...should be taken to reduce human exposure to hazardous substances from a facility and whether additional information on human exposure and associated health risks is needed... ." 42 U.S.C. $ 9604(i)(6)(G). Risks that may have been posed by plant operations in past are not relevant to the decision whether present risks posed by site warrant response actions. This point is made more pointedly in EPA guidance on risk assessments for Superfund sites. "The purpose of the ATSDR health assessment is to assist in the evaluation of data and information on the release of toxic substances into the environment in order to assess any current or future impact on public health, develop health advisories or other health related recommendations, and identify studies or actions needed to evaluate and prevent human health effects." Risk Assessment Guidance for Superfund, Volume I, Human Health Evaluation Manual (Part A), EPA/540/1-89/002, ("RAGS") p.2-10. We therefore request that ATSDR revise the health assessment for the THAN site and the summary Fact Sheet to focus on the assessment of risks posed by present site conditions, and that speculations concerning historical plant operating conditions and the potential risks posed by such operations be deleted from the assessment. Unless the health assessment focuses on present and future risks associated with current site conditions, it fails to serve the purpose that CERCLA requres it to serve. This failure is a disservice to the THAN site and to the nearby community.

CDHS response: It is the mandate of ATSDR and thus CDHS to assess the current and future public health impact that a site may pose but to do this it is imperative to evaluate past and current exposure, since we are assuming that exposure must proceed health impact.

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