PUBLIC HEALTH ASSESSMENT

CALLAWAY AND SON DRUM SERVICE
(a/k/a CALLOWAY AND SON DRUM SERVICE)
LAKE ALFRED, POLK COUNTY, FLORIDA

APPENDIX A. FIGURES

Figure 1. Site Location in Florida

Figure 2. Site Location in Lake Alfred

Figure 3. Site Layout

Figure 4. Sampling Locations

APPENDIX B. TABLES

Table 1.

Maximum concentrations of organic contaminants in on-site groundwater

Contaminants of Concern (COC)	Maximum Concentration (mg/L)	Sample I.D.	# Greater Than Comparison Value/ Total # of Samples	Comparison Value*
				(mg/L)	Source
Gamma Chlordane	0.036J	TW-04	1/5	0.03 (CREG)	ATSDR 2000
Chlorophenol	100JN	TW-05	1/5	50 (Ch. RMEG)	ATSDR 2000
4, 4'- DDE	0.27N	TW-05	1/5	0.1 (CREG)	ATSDR 2000
1,2-Dichloroethylene	160	CGW-02	2/17	70 (LTHA)	ATSDR 2000
3 and/or 4-Cresol	78	TW-05	1/5	4 (GWCTL)	FDEP 1999
Tetrachloroethylene	950	CGW-02	2/17	0.7 (CREG)	ATSDR 2000
Trichloroethylene	110	CGW-02	2/17	3 (CREG)	ATSDR 2000
Vinyl Chloride	33	CGW-02	2/17	0.02 (CREG)	ATSDR 2000

* Comparison values used to select chemicals for further scrutiny, not for determining the possibility of illness.
mg/L = micrograms per liter of groundwater
J - Estimated value
N - Presumptive evidence of presence of material
Ch- Indicates the standard is based on a child's exposure concentration

Table 2.

Maximum inorganic contaminant concentrations in on-site groundwater

Contaminants of Concern (COC)	Maximum Concentration (mg/L)	Sample I.D.	# Greater Than Comparison Value/ Total # of Samples	Comparison Value*
				(mg/L)	Source
Aluminum	270,000	TW-05	3/8	20,000 (Ch. EMEG)	ATSDR 2000
Arsenic	68	TW-05	2/8	0.02 (CREG)	ATSDR 2000
Barium	3,400	TW-05	2/8	700 (Ch. RMEG)	ATSDR 2000
Cadmium	6.4JN	TW-05	1/8	2 (CH. EMEG)	ATSDR 2000
Chromium	530	TW-05	4/15	30 (Ch. RMEG)	ATSDR 2000
Lead	740	TW-05	5/15	15 (GWCTL)	FDEP 1999
Mercury	0.92	TW-05	0/8	2 (LTHA)	ATSDR 2000
Nickel	55	TW-05	0/8	200 (Ch. RMEG)	ATSDR 2000
Selenium	10J	TW-05	0/8	50 (Ch. EMEG)	ATSDR 2000
Thallium	9JN	TW-05	1/8	0.5 (CREG)	ATSDR 2000
Vanadium	1,100	TW-05	2/5	30 (Ch. EMEG)	ATSDR 2000

mg/L = micrograms per liter
* Comparison values used to select chemicals for further scrutiny, not for determining the possibility of illness.
N.A.- Not analyzed
J - Estimated value
N - Presumptive evidence of presence of material
Ch- Indicates the standard is based on a child's exposure concentration

Table 3.

Maximum concentrations of organic contaminants in on-site surface soil (0-6 inches bgs) or sediment

Contaminants of Concern (COC)	Maximum Concentration (mg/kg)	Sample I.D.	# Greater Than Comparison Value/ Total # of Samples	Comparison Value*
				(mg/kg)	Source
Gamma Chlordane	0.023	SS-03	0/10	2 (CREG)	ATSDR 2000
Chlorophenol	N.D.	---	0/11	300 (Ch. RMEG)	ATSDR 2000
4, 4'- DDE	0.017	SS-05	0/11	2 (CREG)	ATSDR 2000
1,2-Dichloroethylene	N.D.	---	0/11	10,000 (Ch. EMEG)	ATSDR 2000
3 and/or 4-Cresol	N.D.	---	0/11	3000 (Ch. RMEG)	ATSDR 2000
Tetrachloroethylene	N.D.	--	0/11	500 (Ch. RMEG)	ATSDR 2000
Trichloroethylene	N.D.	---	0/11	6 (SCTL)	FDEP 1999
Vinyl Chloride	N.D.	---	0/11	0.3 (CREG)	ATSDR 2000

bgs- below ground surface
* Comparison values used to select chemicals for further scrutiny, not for determining the possibility of illness.
mg/kg = micrograms per kilogram of soil
N.D.- Not detected
Ch- Indicates the standard is based on a child's exposure concentration
Note: The one surface water sample taken from the western side of the site was contaminated with dichloroethylene (250 mg/L).

Table 4.

Maximum concentrations of inorganic contaminants in on-site surface soil (0-6 inches bgs) or sediment

Contaminants of Concern (COC)	Maximum Concentration (mg/kg)	Sample I.D.	# Greater Than Comparison Value/ Total # of Samples	Comparison Value*
				(mg/kg)	Source
Aluminum	12,000	SS-03	0/10	100,000 (Ch. EMEG)	ATSDR 2000
Arsenic	6	SS-03	3/10	0.5 (CREG)	ATSDR 2000
Barium	34	SD-03	0/10	4000 (Ch. RMEG)	ATSDR 2000
Cadmium	2.9	SD-01	0/10	10 (CH. EMEG)	ATSDR 2000
Chromium	1500	SS-04	1/10	200 (Ch. RMEG)	ATSDR 2000
Lead	5,300	SS-04	1/10	400 (SCTL)	FDEP 1999
Mercury	N.D.	---	0/10	3.4 (SCTL)	FDEP 1999
Nickel	3.2J	SS-03	0/10	1000 (Ch. RMEG)	ATSDR 2000
Selenium	0.92J	SS-03	0/10	390 (SCTL)	FDEP 1999
Thallium	N.D.	---	0/10	5 (Ch. RMEG)	ATSDR 2000
Vanadium	32	SS-03	0/10	200 (Ch. EMEG)	ATSDR 2000

bgs- below ground surface
* Comparison values used to select chemicals for further scrutiny, not for determining the possibility of illness.
mg/kg = milligrams per kilogram of soil
Ch- Indicates the standard is based on a child's exposure concentration
N.D.- Not detected
J - Estimated value

Table 5.

Maximum concentrations of organic contaminants in off-site groundwater

Contaminants of Concern (COC)	Maximum Concentration (mg/L)	Sample I.D.	# Greater Than Comparison Value/ Total # of Samples	Comparison Value*
				(mg/L)	Source
Gamma Chlordane	0.13	TW-02	1/4	0.03 (CREG)	ATSDR 2000
Chlorophenol	N.D.	---	0/4	50 (Ch. RMEG)	ATSDR 2000
4, 4'- DDE	N.D.	---	0/4	0.1 (CREG)	ATSDR 2000
1,2-Dichloroethylene	N.D.	---	0/11	70 (LTHA)	ATSDR 2000
3 and/or 4-Cresol	N.D.	---	0/4	4 (GWCTL)	FDEP 1999
Tetrachloroethylene	N.D.	---	0/11	0.7 (CREG)	ATSDR 2000
Trichloroethylene	N.D.	---	0/11	3 (CREG)	ATSDR 2000
Vinyl Chloride	N.D.	---	0/11	0.3 (CREG)	ATSDR 2000

* Comparison values used to select chemicals for further scrutiny, not for determining the possibility of illness.
It is important to note that two of the four samples came from private drinking wells south of the site. The first was the public supply well at Palm Shores Mobile Village and the second was the well Camp Hackedy.
mg/L = micrograms per liter of groundwater
N.D.- Not detected
N.A.- Not analyzed
Ch- Indicates the standard is based on a child's exposure concentration

Table 6.

Maximum inorganic contaminant concentrations in off-site groundwater

Contaminants of Concern (COC)	Maximum Concentration (mg/L)	Sample I.D.	# Greater Than Comparison Value/ Total # of Samples	Comparison Value*
				(mg/L)	Source
Aluminum	210,000	TW-02	2/11	20,000 (Ch. EMEG)	ATSDR 2000
Arsenic	110	TW-02	1/11	0.02 (CREG)	ATSDR 2000
Barium	6000	TW-02	1/11	700 (Ch. RMEG)	ATSDR 2000
Cadmium	84JN	TW-02	2/11	2 (CH. EMEG)	ATSDR 2000
Chromium	340	TW-02	2/11	30 (Ch. RMEG)	ATSDR 2000
Lead	2,200	TW-02	2/11	15 (GWCTL)	FDEP 1999
Mercury	26	TW-02	2/11	2 (LTHA)	ATSDR 2000
Nickel	390	TW-02	1/11	200 (Ch. RMEG)	ATSDR 2000
Selenium	170J	TW-02	1/11	50 (Ch. EMEG)	ATSDR 2000
Thallium	27JN	TW-02	1/11	0.5 (CREG)	ATSDR 2000
Vanadium	420	TW-02	2/4	30 (Ch. EMEG)	ATSDR 2000

mg/L = micrograms per liter
* Comparison values used to select chemicals for further scrutiny, not for determining the possibility of illness.
Ch- Indicates the standard is based on a child's exposure concentration
J - Estimated value
N - Presumptive evidence of presence of material

Table 7.

Maximum concentrations of organic contaminants in surface soil (0-6 inches bgs) off-site

Contaminants of Concern (COC)	Maximum Concentration (mg/kg)	Sample I.D.	# Greater Than Comparison Value/ Total # of Samples	Comparison Value*
				(mg/kg)	Source
Gamma Chlordane	N.D.	---	0/3	2 (CREG)	ATSDR 2000
Chlorophenol	N.D.	---	0/3	300 (Ch. RMEG)	ATSDR 2000
4, 4'- DDE	N.D.	---	0/3	2 (CREG)	FDEP 1999
1,2-Dichloroethylene	N.D.	---	0/3	10,000 (Ch. EMEG)	ATSDR 2000
3- and 4-Cresol	N.D.	---	0/3	3000 (Ch. RMEG)	FDEP 1999
Tetrachloroethylene	N.D.	---	0/3	500 (Ch. RMEG)	FDEP 1999
Trichloroethylene	N.D.	---	0/3	6 (SCTL)	FDEP 1999
Vinyl Chloride	N.D.	--	0/3	0.3 (CREG)	ATSDR 2000

bgs- below ground surface
* Comparison values used to select chemicals for further scrutiny, not for determining the possibility of illness.
mg/kg = micrograms per kilogram of soil
N.D.- Not detected
Ch- Indicates the standard is based on a child's exposure concentration

Table 8.

Maximum concentrations of inorganic contaminants in off-site surface soil (0-6 inches bgs) or sediment

Contaminants of Concern (COC)	Maximum Concentration (mg/kg)	Sample I.D.	# Greater Than Comparison Value/ Total # of Samples	Comparison Value*
				(mg/kg)	Source
Aluminum	5,300	SS-02	0/4	100,000 (Ch. EMEG)	ATSDR 2000
Arsenic	0.68J	SS-02	1/4	0.5 (CREG)	ATSDR 2000
Barium	63	SS-02	0/4	4000 (Ch. RMEG)	ATSDR 2000
Cadmium	N.D.	---	0/4	10 (CH. EMEG)	ATSDR 2000
Chromium	5.3	SS-02	0/4	200 (Ch. RMEG)	ATSDR 2000
Lead	15	SS-02	0/4	400 (SCTL)	FDEP 1999
Mercury	N.D.	---	0/1	3.4 (SCTL)	FDEP 1999
Nickel	25	SS-06	0/4	1000 (Ch. RMEG)	ATSDR 2000
Selenium	N.D.	---	0/4	390 (SCTL)	FDEP 1999
Thallium	N.D.	---	0/4	5 (Ch. RMEG)	ATSDR 2000
Vanadium	2.1	SS-02	0/3	200 (Ch. EMEG)	ATSDR 2000

bgs- below ground surface
* Comparison values used to select chemicals for further scrutiny, not for determining the possibility of illness.
Ch- Indicates the standard is based on a child's exposure concentration
J - Estimated value
N.D.- Not detected

Table 9.

Potential Exposure Pathways

Pathway Name	Exposure Pathway Elements					Time
	Source	Environmental Media	Point of Exposure	Route of Exposure	Exposed Population
On-site Soil/sediment Ingestion	On-site soil contamination	On-site soil/sediment	On the property	Incidental ingestion of soil/sediment	On-site residents or trespassers	Current/Future
On-site Soil Inhalation	On-site soil contamination	On-site dusts from soil	On the property	Inhalation of dusts	On-site residents or trespassers	Current/Future
Ingestion of On-site groundwater	On-site soil contamination	Groundwater	On-site wells/Tap water	Ingestion of contaminated groundwater	On-site residents	Future
Inhalation of vapors from on-site groundwater	On-site soil contamination	Groundwater	On-site wells/Tap water	Inhalation of vapors from contaminated water	On-site residents	Future
Off-site Soil/sediment Ingestion	Contaminated surface water in drainage ditch	Off-site soil/sediment	Drainage ditch	Incidental ingestion of soil/sediment	Off-site residents/children	Current/Future
Off-site Soil Inhalation	Contaminated surface water in drainage ditch	Off-site dusts from soil	Drainage ditch	Inhalation of dusts	Off-site residents/children	Current/Future
Ingestion of off-site groundwater	On-site soil contamination	Groundwater	Off-site wells/Tap water	Ingestion of contaminated groundwater	Off-site residents	Current/ Future
Inhalation of vapors from off-site groundwater	Migration of on-site groundwater	Groundwater	Off-site wells/Tap water	Inhalation of vapors from contaminated water	Off-site residents	Current/Future

Table 10.

Total Population Estimation Table

Pathway Types	Estimated Total Population in Potential Exposure Pathways*	Minimum Population*	Maximum Population*
Potential Pathways On-site	0	0	1-50
Potential Pathways Off-site	1300	0	501-2500
Total Potential On and Off-site	1300	0	501-2500
Completed Pathways On-site	10	0	1-50
Completed Pathways Off-site	0	0	0
Total Completed On and Off-site	10	0	1-50
Potential and Completed Pathways On-site	10	0	1-50
Potential and Completed Pathways Off-site	1300	0	501-2500
Total Potential and Completed On and Off-site	1310	0	501-2500

Table 11.

Calculated dose of organic chemicals from residential use of on-site groundwater

Contaminant of Concern (maximum concentration)	Oral MRL (mg/kg/day)	Groundwater- Ingestion (mg/kg/day)		Groundwater- Dermal (mg/kg/day)		Inhalation MRL (mg/m3)	Groundwater- Inhalation (mg/m3)
		Child	Adult	Child	Adult		Child	Adult
Gamma-Chlordane (0.000036 mg/L)	0.0006	0.000002	0.000001	2x10-9	2x10-9	0.00002	N.S.	N.S.
Chlorophenol (0.1 mg/L)	0.005	0.007	0.003	0.0005	0.0003	N.A.	1	1
3 or 4-Cresol (0.078 mg/L)	0.05	0.005	0.002	0.0003	0.00009	N.A.	0.78	0.78
4,4'-DDE (0.00027 mg/L)	0.0005	0.00002	0.000008	0.0001	0.00007	N.A.	0.003	0.003
1,2-Dichloroethylene (0.16 mg/L)	0.2	0.01	0.005	0.0008	0.0006	0.9	1.6	1.6
Tetrachloroethylene (0.95 mg/L)	0.05	0.06	0.03	0.03	0.02	0.27	10	10
Trichloroethylene (0.11 mg/L)	0.2	0.007	0.003	0.0008	0.0005	0.55	1.1	1.1
Vinyl Chloride (0.033 mg/L)	0.00002	0.002	0.0009	0.00007	0.00005	0.078	0.33	0.33

These doses were calculated using Risk Assistant software and accepted values for groundwater consumption, shower inhalation exposure and dermal exposure parameters (EPA, 1991). Bold text indicates that the estimated dose exceeds the appropriate MRL.
N.A.- Not available
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

Table 12.

Calculated dose of metals from residential use of on-site groundwater

Contaminant of Concern (maximum concentration)	Oral MRL (mg/kg/day)	Groundwater- Ingestion (mg/kg/day)		Groundwater- Dermal (mg/kg/day)		Inhalation MRL (mg/m3)	Groundwater- Inhalation (mg/m3)
		Child	Adult	Child	Adult		Child	Adult
Aluminum (270 mg/L)	2	18	8	0.03	0.02	N.A.	N.S.	N.S.
Arsenic (0.068 mg/L)	0.0003	0.005	0.002	0.000007	0.000004	N.A.	N.S.	N.S.
Barium (3.4 mg/L)	0.07*	0.2	0.1	0.0003	0.0002	N.A.	N.S.	N.S.
Cadmium (0.0064 mg/L)	0.0002	0.0004	0.0002	0.0000006	0.0000004	N.A.	N.S.	N.S.
Chromium (0.53 mg/L)	N.A.	0.04	0.02	0.000006	0.000004	0.0005	N.S.	N.S.
Lead (0.74 mg/L)	N.A.	0.05	0.02	0.00007	0.00005	N.A.	N.S.	N.S.
Thallium (0.009 mg/L)	0.00008	0.0006	0.0003	0.000001	0.0000007	N.A.	N.S.	N.S.
Vanadium (1.1 mg/L)	0.003	0.07	0.03	0.0001	0.00007	0.0002	N.S.	N.S.

These doses were calculated using Risk Assistant software and accepted values for groundwater consumption, shower inhalation exposure and dermal exposure parameters (EPA, 1991). Bold text indicates that the estimated dose exceeds the appropriate MRL.
N.A.- Not available
N.S.- Not significant
* - EPA's chronic oral reference dose
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
The estimated doses for chromium and lead are bold because no oral MRL exits. Therefore, both were evaluated for health effects.

Table 13.

Calculated dose of metals from ingestion of on-site surface soil

Contaminant of Concern (maximum concentration)	Oral MRL (mg/kg/day)	Soil/dust- Ingestion (mg/kg/day)		Soil/dust- Dermal (mg/kg/day)		Inhalation MRL (mg/m3)	Soil/dust- Inhalation (mg/m3)
		Child	Adult	Child	Adult		Child	Adult
Arsenic (6 mg/kg)	0.0003	0.00008	0.000009	N.S.	N.S.	N.A.	N.S.	N.S.
Chromium (1500 mg/kg)	N.A.	0.02	0.002	N.S.	N.S.	0.0005	0.00008	0.00008
Lead (5300 mg/kg)	N.A.	0.07	0.008	N.S.	N.S.	N.A.	0.0003	0.0003

These doses were calculated using Risk Assistant software and accepted values for soil exposure parameters (EPA, 1991). Bold text indicates that the estimated dose exceeds the appropriate MRL.
N.A.- Not available
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
The estimated doses for chromium and lead are bold because no oral MRL exits. Therefore, both were evaluated for health effects.

Table 14.

Calculated dose of organic compounds from residential use of off-site groundwater

Contaminant of Concern (maximum concentration)	Oral MRL (mg/kg/day)	Groundwater- Ingestion (mg/kg/day)		Groundwater- Dermal (mg/kg/day)		Inhalation MRL (mg/m3)	Groundwater- Inhalation (mg/m3)
		Child	Adult	Child	Adult		Child	Adult
Gamma-Chlordane ( 0.00013 mg/L)	0.0006	0.000009	0.000004	1x10-8	9x10-9	0.00002	N.S.	N.S.
Chlorophenol (N.D.)	0.005	N.D	N.D	N.D	N.D	N.A.	N.D	N.D
3 and/or 4-Cresol (N.D.)	0.05	N.D	N.D	N.D	N.D	N.A.	N.D	N.D
4,4'-DDE (N.D.)	0.34	N.D	N.D	N.D	N.D	N.A.	N.D	N.D
1,2-Dichloroethylene (N.D.)	0.2	N.D	N.D	N.D	N.D	0.9	N.D	N.D
Tetrachloroethylene (N.D.)	0.05	N.D	N.D	N.D	N.D	0.27	N.D	N.D
Trichloroethylene (N.D.)	0.2	N.D	N.D	N.D	N.D	0.55	N.D	N.D
Vinyl chloride (N.D.)	0.00002	N.D	N.D	N.D	N.D	0.078	N.D	N.D

These doses were calculated using Risk Assistant software and accepted values for groundwater consumption, shower inhalation exposure and dermal exposure parameters (EPA, 1991). Bold text indicates that the estimated dose exceeds the appropriate MRL.
N.D.- Not detected
N.A.- Not available
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

Table 15.

Calculated dose of metals from residential use of off-site groundwater

Contaminant of Concern (maximum concentration)	Oral MRL (mg/kg/day)	Groundwater- Ingestion (mg/kg/day)		Groundwater- Dermal (mg/kg/day)		Inhalation MRL (mg/m3)	Groundwater- Inhalation (mg/m3)
		Child	Adult	Child	Adult		Child	Adult
Aluminum (210 mg/L)	2	14	6	0.02	0.01	N.A.	N.S.	N.S.
Arsenic (0.11mg/L)	0.0003	0.007	0.003	0.00001	0.000007	N.A.	N.S.	N.S.
Barium (6.0 mg/L)	0.07	0.4	0.2	0.0006	0.0004	N.A.	N.S.	N.S.
Cadmium (0.084 mg/L)	0.0002	0.006	0.002	0.000008	0.000006	N.A.	N.S.	N.S.
Chromium (0.34 mg/L)	N.A.	0.02	0.01	0.00003	0.00002	0.0005	N.S.	N.S.
Lead (2.2 mg/L)	N.A.	0.1	0.06	0.0002	0.0001	N.A.	N.S.	N.S.
Mercury (0.026 mg/L)	0.002	0.002	0.0007	0.000002	0.000002	0.0002	N.S.	N.S.
Nickel (0.39 mg/L)	0.02	0.03	0.01	0.00004	0.00003	0.0002	N.S.	N.S.
Selenium (0.17 mg/L)	0.005	0.01	0.005	0.00002	0.00001	N.A.	N.S.	N.S.
Thallium (0.027 mg/L)	0.00008	0.002	0.0008	0.00003	0.00002	N.A.	N.S.	N.S.
Vanadium (0.42 mg/L)	0.003	0.03	0.01	0.00004	0.00003	0.0002	N.S.	N.S.

These doses were calculated using Risk Assistant software and accepted values for groundwater consumption, shower inhalation exposure and dermal exposure parameters (EPA, 1991). Bold text indicates that the estimated dose exceeds the appropriate MRL.
N.A.- Not available
N.S.- Not significant
* - EPA's chronic oral reference dose
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
The estimated doses for chromium and lead are bold because no oral MRL exits. Therefore, both were evaluated for health effects.

APPENDIX C. RISK OF ILLNESS, DOSE RESPONSE/THRESHOLD, AND UNCERTAINTY IN PUBLIC HEALTH ASSESSMENTS

Risk of Illness

In this health assessment, the risk of illness is the chance that exposure to a hazardouscontaminant is associated with a harmful health effect or illness. The risk of illness is nota measure of cause and effect; only an in-depth health study can identify a cause andeffect relationship. Instead, we use the risk of illness to decide if a follow-up health studyis 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 determinesthe risk of illness. Exposure to a hazardous contaminant above a minimum level increaseseveryone's risk of illness. Only in unusual circumstances, however, do many peoplebecome ill.

Information from human studies provides the strongest evidence that exposure to ahazardous contaminant is related to a particular illness. Some of this evidence comes fromdoctors reporting an unusual incidence of a specific illness in exposed individuals. Moreformal studies compare illnesses in people with different levels of exposure. However,human information is very limited for most hazardous contaminants, and scientists mustfrequently depend upon data from animal studies. Hazardous contaminants associatedwith harmful health effects in humans are often associated with harmful health effects inother animal species. There are limits, however, in only relying on animal studies. Forexample, scientists have found some hazardous contaminants are associated with cancerin animals, but lack evidence of a similar association in humans. In addition, humans andanimals 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 hazardouscontaminants 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 relationshipbetween exposure to different doses of a specific contaminant and the chance of havinga health effect from each exposure level. This dose-response relationship provides amathematical formula or graph that we use to estimate a person's risk of illness. There isone important difference between the dose-response curves used to estimate the risk ofnoncancerous illnesses and those used to estimate the risk of cancer: the existence of athreshold dose. A threshold dose is the highest exposure dose at which there is no riskof a noncancerous illness. The dose-response curves for noncancerous illnesses includea threshold dose that is greater than zero. Scientists include a threshold dose in thesemodels because the human body can adjust to varying amounts of cell damage withoutillness. The threshold dose differs for different contaminants and different exposureroutes, and we estimate it from information gathered in human and animal studies. Incontrast, the dose-response curves used to estimate the risk of cancer assume there is nothreshold dose (or, the cancer threshold dose is zero). This assumes a single contaminantmolecule may be sufficient to cause a clinical case of cancer. This assumption is veryconservative, and many scientists believe a threshold dose greater than zero exists for thedevelopment of cancer.

Uncertainty

All risk assessments, to varying degrees, require the use of assumptions, judgements, andincomplete data. These contribute to the uncertainty of the final risk estimates. Somemore important sources of uncertainty in this Public Health Assessment includeenvironmental sampling and analysis, exposure parameter estimates, use of modeleddata, and present toxicological knowledge. These uncertainties may cause risk to beoverestimated or underestimated to a different extent. Because of the uncertaintiesdescribed below, this Public Health Assessment does not represent an absolute estimateof risk to persons exposed to chemicals at or near Callaway and Son.

Environmental chemistry analysis errors can arise from random errors in the sampling andanalytical processes, resulting in either an over- or under-estimation of risk. We cancontrol these errors to some extent by increasing the number of samples collected andanalyzed and by sampling the same locations over several different periods. The aboveactions tend to minimize uncertainty contributed from random sampling errors.

There are two areas of uncertainty related to exposure parameter estimates. The first isthe exposure-point concentration estimate. The second is the estimate of the totalchemical exposures. In this assessment we used maximum detected concentrations asthe exposure point concentration. We believe using the maximum measured value to beappropriate because we cannot be certain of the peak contaminant concentrations, andwe cannot statistically predict peak values. Nevertheless, this assumption introducesuncertainty into the risk assessment that may over- or under-estimate the actual risk ofillness. When selecting parameter values to estimate exposure dose, we used defaultassumptions and values within the ranges recommended by the ATSDR or the EPA. These default assumptions and values are conservative (health protective) and maycontribute to the over-estimation of risk of illness. Similarly, we assumed the maximumexposure period occurred regularly for each selected pathway. Both assumptions are likelyto contribute to the over-estimation of risk of illness.

There are also data gaps and uncertainties in the design, extrapolation, and interpretationof toxicological experimental studies. Data gaps contribute uncertainty becauseinformation is either not available or is addressed qualitatively. Moreover, the availableinformation on the interaction among chemicals found at the site, when present, isqualitative (that is, a description instead of a number) and we cannot apply a mathematicalformula to estimate the dose. These data gaps may tend to underestimate the actual riskof 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 uncertainbecause of the differences in the uptake, metabolism, distribution, and body organsusceptibility between different species. Human populations are also variable because ofdifferences in genetic constitution, diet, home and occupational environment, activitypatterns, and other factors. These uncertainties can result in an over- or under-estimationof risk of illness. Finally, there are great uncertainties in extrapolating from high to lowdoses, and controversy in interpreting these results. Because the models used to estimatedose-response relationships in experimental studies are conservative, they tend tooverestimate the risk. Techniques used to derive acceptable exposure levels account forsuch variables by using safety factors. Currently, there is much debate in the scientificcommunity about how much we overestimate the actual risks and what the risk estimatesreally mean.

APPENDIX D. ATSDR PLAIN LANGUAGE GLOSSARY OF ENVIRONMENTAL HEALTH TERMS Revised -15 Dec 99

Absorption:

How a chemical enters a person's blood after the chemical has been swallowed, has come into contact with the skin, or has been breathed in.

Acute Exposure:

Contact with a chemical that happens once or only for a limited period of time. ATSDR defines acute exposures as those that might last up to 14 days.

Additive Effect:

A response to a chemical mixture, or combination of substances, that might be expected if the known effects of individual chemicals, seen at specific doses, were added together.

Adverse Health Effect:

A change in body function or the structures of cells that can lead to disease or health problems.

Antagonistic Effect:

A response to a mixture of chemicals or combination of substances that is less than might be expected if the known effects of individual chemicals, seen at specific doses, were added together.

ATSDR:

The Agency for Toxic Substances and Disease Registry. ATSDR is a federal health agency in Atlanta, Georgia that deals with hazardous substance and waste site issues. ATSDR gives people information about harmful chemicals in their environment and tells people how to protect themselves from coming into contact with chemicals.

Background Level:

An average or expected amount of a chemical in a specific environment. Or, amounts of chemicals that occur naturally in a specific environment.

Biota:

Used in public health, things that humans would eat - including animals, fish and plants.

CAP:

See Community Assistance Panel.

Cancer:

A group of diseases which occur when cells in the body become abnormal and grow, or multiply, out of control

Carcinogen:

Any substance shown to cause tumors or cancer in experimental studies.

CERCLA:

See Comprehensive Environmental Response, Compensation, and Liability Act.

Chronic Exposure:

A contact with a substance or chemical that happens over a long period of time. ATSDR considers exposures of more than one year to be chronic.

Completed Exposure Pathway:

See Exposure Pathway.

Community Assistance Panel (CAP):

A group of people from the community and health and environmental agencies who work together on issues and problems at hazardous waste sites.

Comparison Value (CVs):

Concentrations or the amount of substances in air, water, food, and soil that are unlikely, upon exposure, to cause adverse health effects. Comparison values are used by health assessors to select which substances and environmental media (air, water, food and soil) need additional evaluation while health concerns or effects are investigated.

Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA):

CERCLA was put into place in 1980. It is also known as Superfund. This act concerns releases of hazardous substances into the environment, and the cleanup of these substances and hazardous waste sites. ATSDR was created by this act and is responsible for looking into the health issues related to hazardous waste sites.

Concern:

A belief or worry that chemicals in the environment might cause harm to people.

Concentration:

How much or the amount of a substance present in a certain amount of soil, water, air, or food.

Contaminant:

See Environmental Contaminant.

Delayed Health Effect:

A disease or injury that happens as a result of exposures that may have occurred far in the past.

Dermal Contact:

A chemical getting onto your skin. (see Route of Exposure).

Dose:

The amount of a substance to which a person may be exposed, usually on a daily basis. Dose is often explained as "amount of substance(s) per body weight per day".

Dose / Response:

The relationship between the amount of exposure (dose) and the change in body function or health that result.

Duration:

The amount of time (days, months, years) that a person is exposed to a chemical.

Environmental Contaminant:

A substance (chemical) that gets into a system (person, animal, or the environment) in amounts higher than that found in Background Level, or what would be expected.

Environmental Media:

Usually refers to the air, water, and soil in which chemcials of interest are found. Sometimes refers to the plants and animals that are eaten by humans. Environmental Media is the second part of an Exposure Pathway.

Environmental Protection Agency (EPA):

The federal agency that develops and enforces environmental laws to protect the environment and the public's health.

Epidemiology:

The study of the different factors that determine how often, in how many people, and in which people will disease occur.

Exposure:

Coming into contact with a chemical substance.(For the three ways people can come in contact with substances, see Route of Exposure.)

Exposure Assessment:

The process of finding the ways people come in contact with chemicals, how often and how long they come in contact with chemicals, and the amounts of chemicals with which they come in contact.

Exposure Pathway:

A description of the way that a chemical moves from its source (where it began) to where and how people can come into contact with (or get exposed to) the chemical.

ATSDR defines an exposure pathway as having 5 parts:

1. Source of Contamination,
2. Environmental Media and Transport Mechanism,
3. Point of Exposure,
4. Route of Exposure, and
5. Receptor Population.

When all 5 parts of an exposure pathway are present, it is called a Completed Exposure Pathway. Each of these 5 terms is defined in this Glossary.

Frequency:

How often a person is exposed to a chemical over time; for example, every day, once a week, twice a month.

Hazardous Waste:

Substances that have been released or thrown away into the environment and, under certain conditions, could be harmful to people who come into contact with them.

Health Effect:

ATSDR deals only with Adverse Health Effects (see definition in this Glossary).

Indeterminate Public Health Hazard:

The category is used in Public Health Assessment documents for sites where important information is lacking (missing or has not yet been gathered) about site-related chemical exposures.

Ingestion:

Swallowing something, as in eating or drinking. It is a way a chemical can enter your body (See Route of Exposure).

Inhalation:

Breathing. It is a way a chemical can enter your body (See Route of Exposure).

LOAEL:

Lowest Observed Adverse Effect Level. The lowest dose of a chemical in a study, or group of studies, that has caused harmful health effects in people or animals.

Malignancy:

See Cancer.

MRL:

Minimal Risk Level. An estimate of daily human exposure - by a specified route and length of time -- to a dose of chemical that is likely to be without a measurable risk of adverse, noncancerous effects. An MRL should not be used as a predictor of adverse health effects.

NPL:

The National Priorities List. (Which is part of Superfund.) A list kept by the U.S. Environmental Protection Agency (EPA) of the most serious, uncontrolled or abandoned hazardous waste sites in the country. An NPL site needs to be cleaned up or is being looked at to see if people can be exposed to chemicals from the site.

NOAEL:

No Observed Adverse Effect Level. The highest dose of a chemical in a study, or group of studies, that did not cause harmful health effects in people or animals.

No Apparent Public Health Hazard:

The category is used in ATSDR's Public Health Assessment documents for sites where exposure to site-related chemicals may have occurred in the past or is still occurring but the exposures are not at levels expected to cause adverse health effects.

No Public Health Hazard:

The category is used in ATSDR's Public Health Assessment documents for sites where there is evidence of an absence of exposure to site-related chemicals.

PHA:

Public Health Assessment. A report or document that looks at chemicals at a hazardous waste site and tells if people could be harmed from coming into contact with those chemicals. The PHA also tells if possible further public health actions are needed.

Plume:

A line or column of air or water containing chemicals moving from the source to areas further away. A plume can be a column or clouds of smoke from a chimney or contaminated underground water sources or contaminated surface water (such as lakes, ponds and streams).

Point of Exposure:

The place where someone can come into contact with a contaminated environmental medium (air, water, food or soil). For examples: the area of a playground that has contaminated dirt, a contaminated spring used for drinking water, the location where fruits or vegetables are grown in contaminated soil, or the backyard area where someone might breathe contaminated air.

Population:

A group of people living in a certain area; or the number of people in a certain area.

PRP:

Potentially Responsible Party. A company, government or person that is responsible for causing the pollution at a hazardous waste site. PRP's are expected to help pay for the clean up of a site.

Public Health Assessment(s):

See PHA.

Public Health Hazard:

The category is used in PHAs for sites that have certain physical features or evidence of chronic, site-related chemical exposure that could result in adverse health effects.

Public Health Hazard Criteria:

PHA categories given to a site which tell whether people could be harmed by conditions present at the site. Each are defined in the Glossary. The categories are:

1. Urgent Public Health Hazard
2. Public Health Hazard
3. Indeterminate Public Health Hazard
4. No Apparent Public Health Hazard
5. No Public Health Hazard

Receptor Population:

People who live or work in the path of one or more chemicals, and who could come into contact with them (See Exposure Pathway).

Reference Dose (RfD):

An estimate, with safety factors (see safety factor) built in, of the daily, life-time exposure of human populations to a possible hazard that is not likely to cause harm to the person.

Route of Exposure:

The way a chemical can get into a person's body. There are three exposure routes:

- breathing (also called inhalation),
- eating or drinking (also called ingestion), and
- or getting something on the skin (also called dermal contact).

Safety Factor:

Also called Uncertainty Factor. When scientists don't have enough information to decide if an exposure will cause harm to people, they use "safety factors" and formulas in place of the information that is not known. These factors and formulas can help determine the amount of a chemical that is not likely to cause harm to people.

SARA:

The Superfund Amendments and Reauthorization Act in 1986 amended CERCLA and expanded the health-related responsibilities of ATSDR. CERCLA and SARA direct ATSDR to look into the health effects from chemical exposures at hazardous waste sites.

Sample Size:

The number of people that are needed for a health study.

Sample:

A small number of people chosen from a larger population (See Population).

Source (of Contamination):

The place where a chemical comes from, such as a landfill, pond, creek, incinerator, tank, or drum. Contaminant source is the first part of an Exposure Pathway.

Special Populations:

People who may be more sensitive to chemical exposures because of certain factors such as age, a disease they already have, occupation, sex, or certain behaviors (like cigarette smoking). Children, pregnant women, and older people are often considered special populations.

Statistics:

A branch of the math process of collecting, looking at, and summarizing data or information.

Superfund Site:

See NPL.

Survey:

A way to collect information or data from a group of people (population). Surveys can be done by phone, mail, or in person. ATSDR cannot do surveys of more than nine people without approval from the U.S. Department of Health and Human Services.

Synergistic effect:

A health effect from an exposure to more than one chemical, where one of the chemicals worsens the effect of another chemical. The combined effect of the chemicals acting together are greater than the effects of the chemicals acting by themselves.

Toxic:

Harmful. Any substance or chemical can be toxic at a certain dose (amount). The dose is what determines the potential harm of a chemical and whether it would cause someone to get sick.

Toxicology:

The study of the harmful effects of chemicals on humans or animals.

Tumor:

Abnormal growth of tissue or cells that have formed a lump or mass.

Uncertainty Factor:

See Safety Factor.

Urgent Public Health Hazard:

This category is used in ATSDR's Public Health Assessment documents for sites that have certain physical features or evidence of short-term (less than 1 year), site-related chemical exposure that could result in adverse health effects and require quick intervention to stop people from being exposed.

CERTIFICATION

This Callaway and Son Drum Service site Public Health Assessment 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.

Richard Gillig
Chief, SSAB, DHAC, ATSDR

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