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1. ATSDR > Public Health Assessments & Consultations

PUBLIC HEALTH ASSESSMENT

MOUNTAIN PINE PRESSURE TREATING
PLAINVIEW, YELL COUNTY, ARKANSAS

APPENDICES

APPENDIX A: FIGURE

Figure 1. Mountain Pine Pressure Treatment Site Map

APPENDIX B: TABLES

Comparison Values Used In Screening Contaminants For Further Evaluation

Environmental Media Evaluation Guides (EMEGs) are developed for chemicals based on their toxicity, frequency of occurrence at National Priority List (NPL) sites, and potential for human exposure. They are derived to protect the most sensitive populations and are not action levels, but rather comparison values. They do not consider carcinogenic effects, chemical interactions, multiple route exposure, or other media-specific routes of exposure, and are very conservative concentration values designed to protect sensitive members of the population.

Reference Dose Media Evaluation Guides (RMEGs) are another type of comparison value derived to protect the most sensitive populations. They do not consider carcinogenic effects, chemical interactions, multiple route exposure, or other media-specific routes of exposure, and are very conservative concentration values designed to protect sensitive members of the population.

Cancer Risk Evaluation Guides (CREGs) are estimated contaminant concentrations based on a probability of one excess cancer in a million persons exposed to a chemical over a lifetime. These are also very conservative values designed to protect sensitive members of the population.

Maximum Contaminant Levels (MCLs) have been established by USEPA for public water supplies to reduce the chances of adverse health effects from contaminated drinking water. These standards are well below levels for which health effects have been observed and take into account the financial feasibility of achieving specific contaminant levels. These are enforceable limits that public water supplies must meet.

Maximum Contaminant Level Goal (MCLG) is a non-enforceable drinking water health goal. There are no known or anticipated adverse effects on the health of persons drinking water containing concentrations at or below the MCLG.

TABLE 1: Concentrations of Contaminants of Concern in On-site Soil, Sediment, and Groundwater Samples, Mountain Pine Pressure Treating, Inc. Site, 1997.

Constituent	Concentration Range (mg/kg) 1	Health Based Comparison Value (mg/kg)
SOIL AND SEDIMENT
Naphthalene	0.36	1000(EMEG) 2
Dibenzofuran	0.32	230 (RMEG) 3
Pentachlorophenol	10.65 - 202	50 (EMEG)
Phenanthrene	1 - 1.85	30000 (RMEG)
Benzo(a)anthracene	0.28	0.62 (RMEG)
Chrysene	0.25	62 (RMEG)
Arsenic	6.6 - 2182	20 (EMEG)
Cadmium	2.6 - 8.33	10 (EMEG)
Chromium (total)	29.2 - 2984	200 (RMEG)
Copper	8.4 - 2400	2900 (RMEG)
Nickel	14.9 - 50.4	1000 (RMEG)
Lead	30.3 - 211	400 (RMEG)
Zinc	38.5 - 1152	20000 (EMEG)
GROUNDWATER
Chromium	0.0006 - 0.0017	0.03 (RMEG)
Copper	0.01	1.3 (MCLG) 4
Lead	0.0015	0.015 (MCL) 5
Zinc	0.012	3 (EMEG)
Bold text indicates a contaminant that exceeded ATSDR's Comparison Value in at least one sample. 1 mg/kg = milligrams per kilogram 2 EMEG = Environmental Media Evaluation Guide 3 RMEG = Reference Dose Media Evaluation Guide 4 MCLG = Maximum Contaminant Level Goal 5 MCL = Maximum Contaminant Level

Table 2: Polychlorinated Dioxins and Furans Found in On-site Soil Samples, Mountain Pine Pressure Treating, Inc. Site, 1997.

Constituent		Concentrations in parts per million (ppm)
		SS-3	SS-4	SS-5	SS-6	SS-7	SS-9	SS-10	SS-11	SS-13
2,3,7,8 TCDD 1		0	0	0	0	0	0	0	0	0
1,2,3,4,6,7,8 HpCDD 2		0	0.0009	0	0	1.76	5.658	0.0088	0.0022	0
1,2,3,4,7,8 HxCDF 3		0	0	0	0.004	0	0	0	0	0
1,2,3,6,7,8 HxCDF		0	0	0	0.003	0.019	0	0	0	0
1,2,3,7,8,9 HxCDF		0	0	0.0032	0.0476	0.27	0	0.0023	0	0
1,2,3,4,6,7,8 HpCDF 4		0	0	0.0071	0.0725	0.33	0	0.003	0.001	0
OCDD 5		0.0025	0.0074	0.2215	2.33	15.139	60.39	0.078	0.0295	0.0025
OCDF 6		0	0.00065	0.01	0.134	0.497	1.176	0.0039	0.0009	0
Total (ppm)		0.0025	0.009	0.2418	2.5911	18.015	67.224	0.096	0.0336	0.0025
		Toxicity Equivalent
Constituent	TEF 7
2,3,7,8 TCDD	1
1,2,3,4,6,7,8 HpCDD	0.01		9.00e-06			1.76e-02	5.66e-02	8.80e-05	2.20e-05
1,2,3,4,7,8 HxCDF	0.1				4.00e-04
1,2,3,6,7,8 HxCDF	0.1				3.00e-04	1.90e-03
1,2,3,7,8,9 HxCDF	0.1			3.20e-04	4.76e-03	2.70e-02		7.36e-07
1,2,3,4,6,7,8 HpCDF	0.01			7.10e-05	7.25e-04	3.30e-03		2.13e-07	7.10e-08
OCDD	0.0001	2.50e-07	7.40e-07	2.22e-05	2.33e-04	1.51e-03	1.34e-03	1.73e-06	6.53e-07	5.54e-08
OCDF	0.0001		6.50e-08	1.00e-06	1.34e-05	4.97e-05	1.18e-06	3.90e-09	9.00e-10	0.00e+00
Total (ppm)		2.50e-07	9.81e-06	4.14e-04	6.43e-03	5.14e-02	5.79e-02	9.07e-05	2.27e-05	5.54e-08
Total (ppb) 8		2.50e-04	9.80e-03	4.14e-01	6.43e+00	5.14e+01	1.34e+00	2.68e-03	7.25e-04	5.54e-05
Comparison Value (ppb)		5.00e-02	5.00e-02	5.00e-02	5.00e-02	5.00e-02	5.00e-02	5.00e-02	5.00e-02	5.00e-02
Bold text indicates a contaminant that exceeded ATSDR's Comparison Value in at least one sample 1 TCDD-tetra-chlorinated dioxin; 2 HpCDD-hepta-chlorinated dioxin; 3 HxCDF-hexa-chlorinated furan; 4 HpCDF-hepta-chlorinated furan; 5 OCDD-octa-chlorinated dioxin; 6 OCDF-octa-chlorinated furan; 7 TEF-toxicity equivalency factor; 8 ppb- parts per billion.

Table 3: Polychlorinated Dioxins and Furans Found in Sediment Samples, Mountain Pine Pressure Treating Inc. Site, February 22, 1993.

Constituent		Concentrations in parts per million (ppm)
		SD-1	SD-2	SD-3	SD-4	SD-5	SD-6	SD-7	SD-8
2,3,7,8 TCDD 1		0	0	0	0	0	0	0	0
1,2,3,6,7,8 HxCDD 2		0	0	0.0022	0.0013	0	0	0.0269	0
1,2,3,7,8,9 HxCDD		0	0.0077	0.0011	0.0009	0	0	0.048	0
1,2,3,4,6,7,8 HpCDD 3		0.0074	0	0.0513	0.0712	0	0	1.176	0.0218
1,2,3,4,7,8 HxCDF 4		0	0	0	0	0	0	0	0
1,2,3,6,7,8 HxCDF		0	0	0	0.0013	0	0	0	0
1,2,3,7,8,9 HxCDF		0	0	0.044	0	0	0	0	0.004
2,3,4,6,7,8 HxCDF		0	0	0.002	0	0	0	0	0
1,2,3,4,6,7,8 HpCDF 5		0	0	0.0756	0.0213	0	0	0	0.0118
1,2,3,4,7,8,9 HpCDF		0	0	0.0018	0	0	0	0	0
OCDD 6		0.0526	1.658	11.155	0.973	0.0078	0.0078	7.13	0.143
OCDF 7		0.0057	0.115	0.096	0.0269	0	0	0.305	0.007
Total (ppm)		0.0657	1.7807	11.429	1.0959	0.0078	0.0078	8.6859	0.1876
		Toxicity Equivalent
Constituent	TEF 8
2,3,7,8 TCDD	1
1,2,3,6,7,8 HxCDD	0.1			2.20e-04	1.30e-04			2.69e-03
1,2,3,7,8,9 HxCDD	0.1		7.70e-04	1.10e-04	9.00e-05			4.80e-03
1,2,3,4,6,7,8 HpCDD	0.01	7.40e-05		5.13e-04	7.12e-04			1.18e-02	2.18e-04
1,2,3,4,7,8 HxCDF	0.1
1,2,3,6,7,8 HxCDF	0.1				1.30e-04
1,2,3,7,8,9 HxCDF	0.1			4.40e-03					4.00e-04
2,3,4,6,7,8 HxCDF	0.1			2.00e-04
1,2,3,4,6,7,8 HpCDF	0.01			7.56e-04	2.13e-04				1.18e-04
1,2,3,4,7,8,9 HpCDF	0.01			1.80e-05
OCDD	0.0001	5.26e-06	1.66e-04	1.12e-03	9.73e-05	7.80e-07	7.80e-07	7.13e-04	1.43e-05
OCDF	0.0001	5.70e-07	1.15e-05	9.60e-06	2.69e-06			3.05e-05	7.00e-07
Total (ppm)		7.98e-05	9.47e-04	7.34e-03	1.38e-03	7.80e-07	7.80e-07	2.00e-02	7.51e-04
Total (ppb) 9		7.98e-02	9.47e-01	7.34e+00	1.37e+00	7.80e-04	7.80e-04	2.00e+01	7.51e-01
Comparison Value (ppb)		5.00e-02	5.00e-02	5.00e-02	5.00e-02	5.00e-02	5.00e-02	5.00e-02	5.00e-02
Bold text indicates a contaminant that exceeded ATSDR's Comparison Value in at least one sample 1 TCDD-tetra-chlorinated dioxin; 2 HxCDD-hexa-chlorinated dioxin; 3 HpCDD-hepta-chlorinated dioxin; 4 HxCDF-hexa-chlorinated furan; 5 HpCDF-hepta-chlorinated furan; 6 OCDD-octa-chlorinated dioxin; 7 OCDF-octa-chlorinated furan; 8 TEF-toxicity equivalency factor; 9 ppb- parts per billion.

TABLE 4: Nimrod Lake Sediment Samples, Mountain Pine Pressure Treating Inc. Site; May 14, 1998.

Constituent	Maximum Sediment concentration (mg/kg) 1		Health based comparison value (mg/kg)
	Mouth Porter Creek	Vicinity of Water Intake
Aluminum	23.3	19.3	100,000 (EMEG) 2
Arsenic	6.7	3.0	20 (RMEG) 3
Barium	0.156	0.137	4000 (RMEG)
Calcium	537	461	NA 4
Chromium	35.8	29.8	200 (RMEG)
Copper	ND	0.7	2900 (RMEG)
Iron	29.7	27.5	23000 (RMEG)
Magnesium	1870	1620	NA
Manganese	0.56	0.55	3000 (RMEG)
Nickel	34.9	31.7	1000 (RMEG)
Lead	23.5	26.4	400 (RMEG)
Benzo(a)pyrene	0.18	ND 5	0.1 (CREG) 6
OCDD 7	0.006	0.005	NA
HpCDF 8	0.0048	0.00278	NA
Bold text indicates sample concentration that exceeded comparison value 1 mg/kg = milligrams per kilogram; 2 EMEG = Environmental Media Evaluation Guide; 3 RMEG = Reference Dose Media Evaluation Guide; 4 NA = not applicable (no comparison value has been established); 5 ND = not detected; 6 CREGs = Cancer Risk Evaluation Guides; 7 OCDD-octa-chlorinated dioxin; 8 .HpCDF-hepta-chlorinated furan.

TABLE 4 (continued): Toxicity Equivalents for Polychlorinated Dioxins and Furans, Nemrod Lake Sediment Samples, Mountain Pine Pressure Treating Inc. Site, May 14, 1998.

Constituent	Concentration (mg/kg) 1	TEF 2	TEQ 3 (ppb) 4	Comparison Value (ppb)
OCDD 5	0.006	0.0001	0.000600	0.05
HpCDF 6	0.0048	0.0001	0.000480	0.05
1 mg/kg -milligrams per kilogram; 2 TEF-toxicity equivalency factor; 3 TEQ-Toxicity equivalents (TEQ); 4 ppb-parts per billion; 5 OCDD-octa-chlorinated dioxin; 6 HpCDF-hepta-chlorinated furan.

TABLE 5: Nimrod Lake Fish Samples, Mountain Pine Pressure Treating Inc. Site, May 14, 1998.

Constituent	Maximum fish concentration (mg/kg) 1 from five samples		Estimated Ingestion Dose mg/kg/day 2	Health based comparison dose mg/kg /day
	Mouth Porter Creek	Vicinity of Water Intake
Mercury	0.64	0.71	0.02	0.003 (MRL) 3
Benzoic Acid	0.2941	0.3370	0.009	4.0 (RfD) 4
4-chloro-3-methylphenol	0.0434	0.0756	0.002	0.05 (MRL for p-cresols)
Naphthalene	0.0143	0.0085	0.0003	0.02 (MRL)
Phenanthrene	0.0155	ND	0.0005	2.6 (Cancer Effect Level for PAH 5)
Phenol	0.0571	0.0794	0.002	0.003 (NOAEL6 : human)
1 mg/kg- milligrams per kilogram; 2 mg/kg/day- milligrams per kilogram per day; 3 MRL- Minimal Risk Level; 4 RfD- reference dose; 5 PAH- polycyclic aromatic hydrocarbons; 6 NOAEL- no observed adverse effect level.

TABLE 6: Off-site Soil and Sediment Samples, Mountain Pine Pressure Treating Inc. Site, Expanded Site Inspection: February 22, 1993.

Constituent	Concentration Range (mg/kg) 1		Health Based Comparison Value (mg/kg)
	SOIL	SEDIMENT
Arsenic	7.4 - 14.0	11.4 - 53.3	0.5 (CREG 2) 0.6 (Pica child EMEG 3) 20 (EMEG)
Chromium (total)	26.6 - 38.6	21.8 - 142.0	10 (Pica child EMEG) 200 (RMEG 4)
Copper	9.6 - 17.3	6.4 - 25.9	2900 (RMEG)
Pentachlorophenol	ND 5	ND - 1.10	6 (CREG) 50 (EMEG)
1 mg/kg = milligrams per kilogram;2 CREG = Cancer Risk Evaluation Guide; 3 EMEG = Environmental Media Evaluation Guide; 4 RMEG = Reference Dose Media Evaluation Guide; 5 ND = not detected

Table 7. Exposure Pathways

Pathway Name	Contaminants of Concern	Source	Transport Media	Point of Exposure	Route of Exposure	Exposed Population	Time	Comments
Completed Exposure Pathway
Off-site soil	Arsenic Chromium	Process Operations	Soil	Residential yards School grounds	Ingestion	Local Area residents	Past Present Future	Data inadequate to assess the extent and magnitude of possible past or present exposures. Off-site soil is considered an indeterminate public health hazard because of limited information.
Potential Exposure Pathway
On-site soil	Arsenic Chromium Pentachlorophenol	Process Operations	Soil	Process area	Ingestion	Trespassers Workers	Past Present Future	Frequency, intensity, and duration of possible exposures considered adequate to result in exposure above levels of health concern. Soil considered to present a public health hazard.
Sediment	Arsenic Chromium Pentachlorophenol	Process Operations	Leachate	Porter Creek Drainage ditches	Ingestion	Local Area residents	Past Present Future	Frequency, intensity, and duration of possible exposures considered inadequate to result in exposure above levels of health concern. Sediment considered to present no apparent public health hazard
Surface Water	Arsenic Chromium Pentachlorophenol Benzo[a]pyrene	Process Operations	Surface Water	Porter Creek Fourche LaFave River Nimrod Lake	Ingestion Dermal Contact	Local Area residents	Past Present Future	Frequency, intensity, and duration of possible exposures considered inadequate to result in exposure above levels of health concern. Surface water considered to present no apparent public health hazard.
Food chain	Benzo[a]pyrene Arsenic Beryllium Manganese	Process Operations	Sediment Fish	Off site	Ingestion	Local Area Residents	Past Present Future	Frequency, intensity, and duration of possible exposures considered inadequate to result in exposure above levels of health concern. Food chain considered to present no apparent public health hazard.
Groundwater	Arsenic Chromium Copper Pentachlorophenol	Infiltration	Groundwater	None Identified	None Identified	None Identified	Past Current Future	We were not able to identify any evidence of past or current human exposure to contaminated groundwater. Groundwater considered to present no public health hazard at this time.

APPENDIX C: DOSE CALCULATIONS

Calculation of Arsenic Exposure Dose
(On-site Soil and Sediment)

Sample	Concentration in parts per million	10 kilograms (kg) Child Dose	Child Dose	Adult Dose	Pica Child Dose
1	6.6	0.0002	0.0001	0.0000	0.0029
2	8.5	0.0002	0.0001	0.0000	0.0037
3	13.7	0.0004	0.0001	0.0000	0.0060
4	13.8	0.0004	0.0001	0.0000	0.0060
5	15.4	0.0004	0.0001	0.0000	0.0067
6	15.6	0.0004	0.0001	0.0000	0.0068
7	16.9	0.0005	0.0001	0.0000	0.0074
8	19.4	0.0005	0.0002	0.0000	0.0085
9	36.5	0.0010	0.0003	0.0001	0.0160
10	38.0	0.0011	0.0003	0.0001	0.0166
11	51.5	0.0014	0.0005	0.0001	0.0225
12	77.4	0.0022	0.0007	0.0002	0.0339
13	85.4	0.0024	0.0007	0.0002	0.0374
14	176.0	0.0049	0.0015	0.0004	0.0770
15	187.0	0.0052	0.0016	0.0004	0.0818
16	307.0	0.0086	0.0027	0.0006	0.1343
17	751.0	0.0210	0.0066	0.0015	0.3286
18	894.0	0.0250	0.0078	0.0018	0.3911
19	2027.0	0.0568	0.0177	0.0041	0.8868
20	2117.0	0.0593	0.0185	0.0042	0.9262
21	2182.0	0.0611	0.0191	0.0044	0.9546
Mean	430.5	0.0121	0.0038	0.0009	0.1883
Bold text numbers are values that exceeded the ATSDR Health Guidelines
Assumptions: Child:10 kg ingesting 200 milligrams (mg) soil Child: 16 kg ingesting 100 mg soil Adult: 70 kg ingesting 100 mg soil Pica : 16 kg ingesting 5,000 mg soil		Dose Calculation: EF = 0.0000014 (5 days/week for 1 year)

Calculation of Chromium Exposure Dose
(On-site Soil and Sediment)

Sample	Concentration in parts per million	10 kilograms (kg) child Dose	Child Dose	Adult Dose	Pica Child Dose
1	29.2	0.0008	0.0003	0.0001	0.0128
2	35.2	0.0010	0.0003	0.0001	0.0154
3	44.9	0.0013	0.0004	0.0001	0.0197
4	46.5	0.0013	0.0004	0.0001	0.0203
5	48.9	0.0014	0.0004	0.0001	0.0214
6	51.0	0.0014	0.0004	0.0001	0.0223
7	51.0	0.0014	0.0004	0.0001	0.0223
8	62.0	0.0017	0.0005	0.0001	0.0271
9	66.0	0.0018	0.0006	0.0001	0.0289
10	83.8	0.0023	0.0007	0.0002	0.0367
11	115.4	0.0032	0.0010	0.0002	0.0505
12	140.0	0.0039	0.0012	0.0003	0.0613
13	155.0	0.0043	0.0014	0.0003	0.0678
14	156.0	0.0044	0.0014	0.0003	0.0683
15	286.0	0.0080	0.0025	0.0006	0.1251
16	656.0	0.0184	0.0057	0.0013	0.2870
17	715.0	0.0200	0.0063	0.0014	0.3128
18	1747.0	0.0489	0.0153	0.0035	0.7643
19	2100.0	0.0588	0.0184	0.0042	0.9188
20	2904.0	0.0813	0.0254	0.0058	1.2705
21	2984.0	0.0836	0.0261	0.0060	1.3055
Mean	594.1	0.0166	0.0052	0.0012	0.2599
Bold text numbers are values that exceeded the ATSDR Health Guidelines
Assumptions: Child:10 kg ingesting 200 milligrams (mg) soil Child: 16 kg ingesting 100 mg soil Adult: 70 kg ingesting 100 mg soil Pica : 16 kg ingesting 5,000 mg soil		Dose Calculation: EF = 0.0000014 (5 days/week for 1 year)

APPENDIX D: GLOSSARY

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.

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.

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.

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.

Congener:

A chemical compound closely related to another and exerting similar effects.

Concentration:

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

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 chemicals 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.

U.S. Environmental Protection Agency (EPA):

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

Exposure:

Coming into contact with a chemical substance.

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:

• Source of Contamination
• Environmental Media and Transport Mechanism
• Point of Exposure
• Route of Exposure
• 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.

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.

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.

Parts Per Million (ppm):

A unit of measure used to express low concentrations of contaminants. For example, 1 once of Chlorine in 1 million ounces of water is 1ppm. One ppm is comparable to one drop of gasoline in a full sized car's tank full of gas.

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.

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.

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:

• Urgent Public Health Hazard
• Public Health Hazard
• Indeterminate Public Health Hazard
• No Apparent Public Health Hazard
• 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.

Risk:

In risk assessment, the probability that something will cause injury, combined with the potential severity of that injury.

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)
• 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).

Semi-Volatile Organic Compounds (SVOCs):

Compounds amenable to analysis by extraction of the sample with an organic solvent. Polycyclic aromatic hydrocarbons, such as naphthalene, phenanthrene, benzo(a)pyrene, and chrysene, comprise one category of SVOCs.

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.

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.

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.

Agency for Toxic Substances and Disease Registry Public Health Conclusion Categories

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