PUBLIC HEALTH ASSESSMENT
QUEEN'S 41st AUTO SALVAGE
(a/k/a QUEENS 41 AUTO)
LAND O'LAKES, PASCO COUNTY, FLORIDA
Figure 1. Site Location in Florida
Figure 3. FDEP Sample Locations (FDEP, 1998)
Figure 4. FDEP Direct Push Sample Locations (FDEP, 1998)
Figure 5. EPA Sample Locations (EPA, 2000a)
Table 1. Total Exposed Population Estimation Table
Pathway Types |
Estimated Total Population in Potential Exposure Pathways |
Minimum Population |
Maximum Population |
Potential Pathways On-site |
0 |
0 |
0 |
Potential Pathways Off-site |
400 |
0 |
51-500 |
Total Potential On- and Off-site |
400 |
0 |
51-500 |
Completed Pathways On-site |
2 |
0 |
1-50 |
Completed Pathways Off-site |
0 |
0 |
0 |
Total Completed On- and Off-site |
2 |
2 |
1-50 |
Potential and Completed Pathways On-site |
2 |
0 |
1-50 |
Potential and Completed Pathways Off-site |
400 |
0 |
51-500 |
Total Potential and Completed On- and Off-site |
402 |
2 |
51-500 |
Table 2. Maximum Concentrations of Contaminants in On-site
Soil
Contaminants of Concern (COC) |
Maximum Concentration (mg/kg) |
Sample ID containing maximum |
# Greater Than Comparison Value/ Total # of Samples |
Comparison Value* |
|
(mg/kg) |
Source |
||||
Arsenic |
2.2 |
QN-04-SB |
2/14 |
0.5 (CREG) | ATSDR 2000 |
Benzene |
N.D. |
--- |
0/19 |
20 (CREG) | ATSDR 2000 |
Chromium |
4.1 |
41ASS02 |
0/14 |
200 (Ch. RMEG) | ATSDR 2000 |
Lead |
100 |
QN-06-SB |
0/14 |
400 (SCTL) | FDEP 2000 |
Tetrachlorotheylene |
190 |
QN-06-SBB |
0/19 |
500 (Ch. RMEG) | ATSDR 2000 |
Trichloroethylene |
0.013 |
QN-06-SBB |
0/19 |
6 (SCTL) | FDEP 2000 |
* Comparison values used to select chemicals for further scrutiny, not for
determining the possibility of illness.
mg/kg = milligrams per kilogram of soil.
SS = soil sample taken from top 12 inches of soil.
SB = soil sample taken 2 to 4 feet below the surface.
SBB = soil sample taken 4 to 8 feet below the surface.
N.D. = Not detected.
Table 3. Maximum Concentrations of Contaminants in On-site
Ground water
Contaminants of Concern (COC) |
Maximum Concentration (mg/L) |
Sample I.D. containing maximum |
# Greater Than Comparison Value/ Total # of Samples |
Comparison Value* |
|
(mg/L) |
Source |
||||
Arsenic |
17 |
QN-11-GW |
3/11 |
0.02 (CREG) | ATSDR 2000 |
Benzene |
79 |
DP-5 |
3/25 |
1 (CREG) | ATSDR 2000 |
Chromium |
53 |
QN-10-GW |
4/11 |
30 (Ch. RMEG) | ATSDR 2000 |
Lead |
N.D. |
--- |
0/11 |
15 (GWCTL) | FDEP 2000 |
Tetrachlorotheylene |
1600 |
QN-04-GW |
7/25 |
0.7 (CREG) | ATSDR 2000 |
Trichloroethylene |
170 |
Potable |
6/25 |
3 (GWCTL) | FDEP 2000 |
* Comparison values used to select chemicals for further scrutiny, not for
determining the possibility of illness.
mg/L = micrograms per liter of ground water.
DP = Sample collected by direct-push technology.
N.D. = Not detected.
Table 4. Maximum Concentrations of Contaminants in Off-site
Soil
Contaminants of Concern (COC) |
Maximum Concentration (mg/kg) |
Sample I.D. containing maximum |
# Greater Than Comparison Value/ Total # of Samples |
Comparison Value* |
|
(mg/kg) |
Source |
||||
Arsenic |
1.9 |
QN-11-SD |
3/20 |
0.5 (CREG) | ATSDR 2000 |
Benzene |
N.D. |
--- |
0/23 |
20 (CREG) | ATSDR 2000 |
Chromium |
25 |
41ASD02 |
0/20 |
200 (Ch. RMEG) | ATSDR 2000 |
Lead |
99 |
QN-11-SD |
0/20 |
400 (SCTL) | FDEP 2000 |
Tetrachlorotheylene |
0.087 |
41ASD03 |
0/23 |
500 (Ch. RMEG) | ATSDR 2000 |
Trichloroethylene |
N.D. |
--- |
0/23 |
6 (SCTL) | FDEP 2000 |
* Comparison values used to select chemicals for further scrutiny, not for
determining the possibility of illness.
mg/kg = milligrams per kilogram of soil.
SD = sample colleted from drainage ditch on southeast side of property (Figure
2, Appendix A).
N.D. = Not detected.
Table 5. Maximum Concentrations of Contaminants in Off-site
Ground water
Contaminants of Concern (COC) |
Maximum Concentration (mg/L) |
Sample I.D. containing maximum |
# Greater Than Comparison Value/ Total # of Samples |
Comparison Value* |
|
(mg/L) |
Source |
||||
Arsenic | 4.4 | QN-14-GWC | 1/11 | 0.02 (CREG) | ATSDR 2000 |
Benzene | N.D. | --- | 0/13 | 1 (CREG) | ATSDR 2000 |
Chromium | 81 | QN-14-GWC | 6/11 | 30 (Ch. RMEG) | ATSDR 2000 |
Lead | 20 | QN-14-GWC | 1/11 | 15 (GWCTL) | FDEP 2000 |
Tetrachlorotheylene | 1.7 | 41APWO2 | 1/13 | 0.7 (CREG) | ATSDR 2000 |
Trichloroethylene | 1.3 | 41APW01 | 0/13 | 3 (GWCTL) | FDEP 2000 |
* Comparison values used to select chemicals for further scrutiny, not for
determining the possibility of illness.
mg/L = micrograms per liter of ground water.
41APW01 is the potable well at a nearby residence.
41APW02 is the irrigation well at a nearby residence.
N.D. = Not detected.
Table 6. Completed Exposure Pathways
Pathway Name |
Exposure Pathway Elements |
Time |
||||
Source |
Environmental/ Exposure Media |
Point of Exposure |
Route of Exposure |
Exposed Population |
||
On-site Ground water | Contaminated On-Site Soil | Ground water | On-site well/ Tap water | Ingestion/ Inhalation |
Caretaker of on-site businesses | 1985-1988 |
On-site Soil | Contaminated On-Site Soil | Surface Soil | On-site property | Ingestion/ Inhalation |
Caretaker of on-site businesses | 1985-Current |
Off-site Sediment | Contaminated On-Site Surface Water | Sediment in the Drainage Ditch | Sediments in the Ditch | Ingestion | Residents of the surrounding area | Past, present, future |
Off-site Ground water | Contaminated On-Site Soil | Ground water | On-site well/ Tap water | Ingestion/ Inhalation |
Nearby residents | 1997-1998 |
Table 7. Potential Exposure Pathways
Pathway Name |
Exposure Pathway Elements |
Time |
||||
Source |
Environmental/ Exposure Media |
Point of Exposure |
Route of Exposure |
Exposed Population and land use |
||
On-site Ground water | Contaminated On-Site Soil | Ground water | On-site wells/ Tap water | Ingestion, skin absorption and inhalation | On-site residents | Future |
Off-site Ground water | Contaminated On-Site Soil | Ground water | Off-site wells/ Tap water |
Ingestion, skin absorption and inhalation | Off-site residents | Future |
Table 8. Estimated Dose from Exposure to On-site Soil
Contaminant of Concern |
Oral MRL |
Soil/dust-Ingestion |
Soil/dust-Dermal |
Inhalation MRL (mg/m3) |
Soil/dust- Inhalation (mg/m3) |
|||
Child |
Adult |
Child |
Adult |
Child |
Adult |
|||
Arsenic (2.2 mg/kg) |
0.0003 | 0.00003 | 0.000003 | N.S. | N.S. | N.A. | N.S. | N.S. |
Benzene (N.D.) | N.A. | --- | --- | --- | --- | 0.013 | --- | --- |
Chromium (N.S.) | N.A. | N.S. | N.S. | N.S. | N.S. | 0.0005 | N.S. | N.S. |
Lead (N.D.) |
N.A. |
--- |
--- |
--- |
--- |
N.A. |
--- |
--- |
Tetrachlorotheylene (N.S.) |
0.05 |
N.S. |
N.S. |
N.S. |
N.S. |
0.27 |
N.S. |
N.S. |
Trichloroethylene (N.S.) | 0.2 | N.S. | N.S. | N.S. | N.S. | 0.55 | N.S. | N.S. |
These doses were calculated using Risk Assistant software and standard values for ground water consumption, shower inhalation exposure and dermal exposure parameters (EPA, 1991).
N.A. = Not available.
N.D. = Not detected.
N.S. = Not significant.
The above doses were calculated using the following values and an average shower time of 0.2 hours:
Adult body weight- | 70 kg | Child body weight- | 15 kg |
Adult soil ingestion- | 100 mg/day | Child soil ingestion- | 200 mg/day |
Adult skin surface area- | 23,000cm2 | Child skin surface area- | 7,200cm2 |
mg/kg/day = milligram of contaminant per kilogram body weight per day.
mg/m3 = milligram of contaminant per cubic meter air.
Table 9. Estimated Dose from Use of On-site Ground water
Contaminant of Concern |
Oral MRL |
Ground water- Ingestion |
Ground water- Dermal |
Inhalation MRL |
Ground water- Inhalation |
|||
Child |
Adult |
Child |
Adult |
Child |
Adult |
|||
Arsenic (0.017 mg/L) | 0.0003 | 0.001 | 0.0005 | 0.000002 | 0.000001 | N.A. | N.S. | N.S. |
Benzene (0.079 mg/L) | N.A. | 0.005 | 0.002 | 0.0005 | 0.0003 | 0.013 | 0.79 | 0.79 |
Chromium (0.053 mg/L) | N.A. | 0.004 | 0.002 | 0.000005 | 0.000003 | 0.0005 | N.S. | N.S. |
Lead (N.D.) | N.A. | --- | --- | --- | --- | N.A. | --- | --- |
Tetrachlorotheylene (1.6 mg/L) |
0.05 |
0.1 |
0.05 |
0.04 |
0.03 |
0.27 |
16 |
16 |
Trichloroethylene (0.17 mg/L) |
0.2 |
0.01 |
0.005 |
0.001 |
0.0008 |
0.55 |
1.7 |
1.7 |
These doses were calculated using Risk Assistant software and standard values for ground water consumption, shower inhalation exposure and dermal exposure parameters (EPA, 1991). Bold text indicates an estimated dose exceeds the appropriate MRL.
N.A. =Not available.
N.D. =Not detected.
N.S. = Not significant.
The above doses were calculated using the following values and an average shower time of 0.2 hours:
Adult body weight- | 70 kg | Child body weight- | 15 kg |
Adult water consumption- | 2 liters/day | Child water consumption- | 1 liter/day |
Adult skin surface area- | 23,000cm2 | Child skin surface area- | 7,200cm2 |
mg/kg/day = milligram of contaminant per kilogram body weight per day.
mg/m3 = milligram of contaminant per cubic meter air.
Table 10. Estimated Dose from Exposure to Off-site Soil
or Sediment
Contaminant of Concern |
Oral MRL |
Soil/dust-Ingestion |
Soil/dust-Dermal |
Inhalation MRL |
Soil/dust- Inhalation (mg/m3) |
|||
Child |
Adult |
Child |
Adult |
Child |
Adult |
|||
Arsenic (1.9 mg/kg) | 0.0003 | 0.00003 | 0.000003 | N.S. | N.S. | N.A. | 0.0001 | 0.0001 |
Benzene (N.D.) | N.A. | --- | --- | --- | --- | 0.013 | --- | --- |
Chromium (N.S.) | N.A. | N.S. | N.S. | N.S. | N.S. | 0.0005 | N.S. | N.S. |
Lead (N.S.) |
N.A. |
N.S. |
N.S. |
N.S. |
N.S. |
N.A. |
N.S. |
N.S. |
Tetrachlorotheylene (N.S.) |
0.05 |
N.S. |
N.S. |
N.S. |
N.S. |
0.27 |
N.S. |
N.S. |
Trichloroethylene (N.D.) | 0.2 | --- | --- | --- | --- | 0.55 | --- | --- |
These doses were calculated using Risk Assistant software and standard values for ground water consumption, shower inhalation exposure and dermal exposure parameters (EPA, 1991).
N.A. = Not available.
N.D. = Not detected.
N.S. = Not significant.
The above doses were calculated using the following values and an average shower time of 0.2 hours:
Adult body weight- | 70 kg | Child body weight- | 15 kg |
Adult soil ingestion- | 100 mg/day | Child soil ingestion- | 200 mg/day |
Adult skin surface area- | 23,000cm2 | Child skin surface area- | 7,200cm2 |
mg/kg/day = milligram of contaminant per kilogram body weight per day.
mg/m3 = milligram of contaminant per cubic meter air.
Table 11. Estimated Dose from Use of Off-Site Ground Water
Contaminant of Concern |
Oral MRL |
Ground water- Ingestion |
Ground water- Dermal |
Inhalation MRL |
Ground water- Inhalation |
|||
Child |
Adult |
Child |
Adult |
Child |
Adult |
|||
Arsenic (0.0044 mg/L) | 0.0003 | 0.0003 | 0.0001 | N.S. | N.S. | N.A. | N.S. | N.S. |
Benzene (N.D.) | N.A. | N.D. | N.D. | N.D. | N.D. | 0.013 | N.D. | N.D. |
Chromium (0.081 mg/L) | N.A. | 0.005 | 0.002 | 0.0000088 | 0.000005 | 0.0005 | N.S. | N.S. |
Lead (0.02 mg/L) |
N.A. |
0.001 |
0.0006 |
0.000002 |
0.000001 |
N.A. |
N.S. |
N.S. |
Tetrachlorotheylene (0.0017 mg/L) |
0.05 |
0.0001 |
0.00005 |
0.00005 |
0.00003 |
0.27 |
0.017 |
0.017 |
Trichloroethylene (N.S.) |
0.2 |
N.S. |
N.S. |
N.S. |
N.S. |
0.55 |
N.S. |
N.S. |
These doses were calculated using Risk Assistant software and standard values for ground water consumption, shower inhalation exposure and dermal exposure parameters (EPA, 1991).
N.A. = Not available.
N.D. = Not detected.
N.S. = Not significant.
The above doses were calculated using the following values and an average shower time of 0.2 hours:
Adult body weight- | 70 kg | Child body weight- | 15 kg |
Adult water consumption- | 2 liters/day | Child water consumption- | 1 liter/day |
Adult skin surface area- | 23,000cm2 | Child skin surface area- | 7,200cm2 |
mg/kg/day = milligram of contaminant per kilogram body weight per day.
mg/m3 = milligram of contaminant per cubic meter air.
APPENDIX C. RISK OF ILLNESS, DOSE RESPONSE/THRESHOLD, AND UNCERTAINTY IN PHAs
Uncertainties are inherent in the public health assessment process. These uncertainties fall into four categories: 1) science is never 100% certain, 2) the inexactness of the risk assessment process, 3) the incompleteness of the information collected thus far, and 4) differences in opinion as to the implications of the information (NJDEP, 1990). These uncertainties are addressed in PHAs by using worst-case assumptions when estimating or interpreting health risks.
Risk of Illness
In this PHA, the risk of illness is the chance that exposure to a hazardous contaminant is associated with a harmful health effect or illness. The risk of illness is not a measure of cause and effect; only an in-depth health study can identify a cause and effect relationship. Instead, we use the risk of illness to decide if a follow-up health study is needed and to identify possible associations.
The greater the exposure to a hazardous contaminant (dose), the greater the risk of illness. The amount of a substance required to harm a person's health (toxicity) also determines the risk of illness. Exposure to a hazardous contaminant above a minimum level increases everyone's risk of illness. Only in unusual circumstances, however, do many people become ill.
Information from human studies provides the strongest evidence that exposure to a hazardous contaminant is related to a particular illness. Some of this evidence comes from doctors reporting an unusual incidence of a specific illness in exposed individuals. More formal studies compare illnesses in people with different levels of exposure. However, human information is very limited for most hazardous contaminants, and scientists must frequently depend upon data from animal studies. Hazardous contaminants associated with harmful health effects in humans are often associated with harmful health effects in other animal species. There are limits, however, in only relying on animal studies. For example, scientists have found some hazardous contaminants are associated with cancer in animals, but lack evidence of a similar association in humans. In addition, humans and animals have differing abilities to protect themselves against low levels of contaminants, and most animal studies test only the possible health effects of high exposure levels. Consequently, the possible effects on humans of low-level exposure to hazardous contaminants are uncertain when information is derived solely from animal experiments.
Dose Response/Thresholds
The focus of toxicological studies in humans or animals is identification of the relationship between exposure to different doses of a specific contaminant and the chance of having a health effect from each exposure level. This dose-response relationship provides a mathematical formula or graph that we use to estimate a person's risk of illness. There is one important difference between the dose-response curves used to estimate the risk of noncancerous illnesses and those used to estimate the risk of cancer: the existence of a threshold dose. A threshold dose is the highest exposure dose at which there is no risk of a noncancerous illness. The dose-response curves for noncancerous illnesses include a threshold dose that is greater than zero. Scientists include a threshold dose in these models because the human body can adjust to varying amounts of cell damage without illness. The threshold dose differs for different contaminants and different exposure routes, and we estimate it from information gathered in human and animal studies. In contrast, the dose-response curves used to estimate the risk of cancer assume there is no threshold dose (or, the cancer threshold dose is zero). This assumes a single contaminant molecule may be sufficient to cause a clinical case of cancer. This assumption is very conservative, and many scientists believe a threshold dose greater than zero exists for the development of cancer.
Uncertainty
All risk assessments, to varying degrees, require the use of assumptions, judgements, and incomplete data. These contribute to the uncertainty of the final risk estimates. Some more important sources of uncertainty in this PHA include environmental sampling and analysis, exposure parameter estimates, use of modeled data, and present toxicological knowledge. These uncertainties may cause risk to be overestimated or underestimated to a different extent. Because of the uncertainties described below, this PHA does not represent an absolute estimate of risk to persons exposed to chemicals at or near Queen's 41st Auto Salvage.
Environmental chemistry analysis errors can arise from random errors in the sampling and analytical processes, resulting in either an over- or under-estimation of risk. We can control these errors to some extent by increasing the number of samples collected and analyzed and by sampling the same locations over several different periods. The above actions tend to minimize uncertainty contributed from random sampling errors.
There are two areas of uncertainty related to exposure parameter estimates: (1) the exposure-point concentration estimate and (2) the estimate of the total chemical exposures. In this assessment we used maximum detected concentrations as the exposure point concentration. We believe using the maximum measured value to be appropriate because we cannot be certain of the peak contaminant concentrations, and we cannot statistically predict peak values. Nevertheless, this assumption introduces uncertainty into the risk assessment that may over- or under-estimate the actual risk of illness. When selecting parameter values to estimate exposure dose, we used default assumptions and values within the ranges recommended by the ATSDR or the EPA. These default assumptions and values are conservative (health protective) and may contribute to the over-estimation of risk of illness. Similarly, we assumed the maximum exposure period occurred regularly for each selected pathway. Both assumptions are likely to contribute to the over-estimation of risk of illness.
There are also data gaps and uncertainties in the design, extrapolation, and interpretation of toxicological experimental studies. Data gaps contribute uncertainty because information is either not available or is addressed qualitatively. Moreover, the available information on the interaction among chemicals found at the site, when present, is qualitative (that is, a description instead of a number) and we cannot apply a mathematical formula to estimate the dose. These data gaps may tend to underestimate the actual risk of illness. In addition, there are great uncertainties in extrapolating from high-to-low doses, and from animal-to-human populations. Extrapolating from animals to humans is uncertain because of the differences in the uptake, metabolism, distribution, and body organ susceptibility between different species. Human populations are also variable because of differences in genetic constitution, diet, home and occupational environment, activity patterns, and other factors. These uncertainties can result in an over- or under-estimation of risk of illness. Finally, there are great uncertainties in extrapolating from high to low doses, and controversy in interpreting these results. Because the models used to estimate dose-response relationships in experimental studies are conservative, they tend to overestimate the risk. Techniques used to derive acceptable exposure levels account for such variables by using safety factors. Currently, there is much debate in the scientific community about how much we overestimate the actual risks and what the risk estimates really mean.
APPENDIX D. ATSDR PLAIN LANGUAGE GLOSSARY OF ENVIRONMENTAL HEALTH TERMS REVISED -15 DEC 99
This Queen's 41st Auto Salvage site PHA was prepared by the Florida Department of Health under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the health assessment was begun.
Debra Gable
Technical Project Officer
Division of Health Assessment and Consultation (DHAC)
ATSDR
The Division of Health Assessment and Consultation, ATSDR, has reviewed this health consultation, and concurs with its findings.
Roberta Erlwein
Section Chief
SPS, SSAB, DHAC,
ATSDR