LOUISIANA ARMY AMMUNITION PLANT
DOYLINE, WEBSTER PARISH, LOUISIANA
APPENDIX A: ATSDR GLOSSARY OF TERMS
The Agency for Toxic Substances and Disease Registry (ATSDR) is a federal public health
agency with headquarters in Atlanta, Georgia, and 10 regional offices in the United States.
ATSDR's mission is to serve the public by using the best science, taking responsive public health
actions, and providing trusted health information to prevent harmful exposures and diseases
related to toxic substances. ATSDR is not a regulatory agency, unlike the U.S. Environmental
Protection Agency (EPA), which is the federal agency that develops and enforces environmental
laws to protect the environment and human health. This glossary defines words used by ATSDR
in communications with the public. It is not a complete dictionary of environmental health terms.
If you have questions or comments, call ATSDR's toll-free telephone number, 1-888-42-ATSDR
(1-888-422-8737).
General Terms
Absorption :
The process of taking in. For a person or an animal, absorption is the process of a substance
getting into the body through the eyes, skin, stomach, intestines, or lungs.
Acute :
Occurring over a short time [compare with chronic].
Acute exposure :
Contact with a substance that occurs once or for only a short time (up to 14 days) [compare with
intermediate duration exposure and chronic exposure].
Additive effect :
A biologic response to exposure to multiple substances that equals the sum of responses of all the
individual substances added together [compare with antagonistic effect and synergistic effect].
Adverse health effect :
A change in body function or cell structure that might lead to disease or health problems
Aerobic :
Requiring oxygen [compare with anaerobic].
Ambient :
Surrounding (for example, ambient air).
Anaerobic :
Requiring the absence of oxygen [compare with aerobic].
Analyte :
A substance measured in the laboratory. A chemical for which a sample (such as water, air, or
blood) is tested in a laboratory. For example, if the analyte is mercury, the laboratory test will
determine the amount of mercury in the sample.
Analytic epidemiologic study :
A study that evaluates the association between exposure to hazardous substances and disease by
testing scientific hypotheses.
Antagonistic effect :
A biologic response to exposure to multiple substances that is less than would be expected if the
known effects of the individual substances were added together [compare with additive effect
and synergistic effect].
Background level :
An average or expected amount of a substance or radioactive material in a specific environment,
or typical amounts of substances that occur naturally in an environment.
Biodegradation :
Decomposition or breakdown of a substance through the action of microorganisms (such as
bacteria or fungi) or other natural physical processes (such as sunlight).
Biologic indicators of exposure study :
A study that uses (a) biomedical testing or (b) the measurement of a substance [an analyte], its
metabolite, or another marker of exposure in human body fluids or tissues to confirm human
exposure to a hazardous substance [also see exposure investigation].
Biologic monitoring :
Measuring hazardous substances in biologic materials (such as blood, hair, urine, or breath) to
determine whether exposure has occurred. A blood test for lead is an example of biologic
monitoring.
Biologic uptake :
The transfer of substances from the environment to plants, animals, and humans.
Biomedical testing :
Testing of persons to find out whether a change in a body function might have occurred because
of exposure to a hazardous substance.
Biota :
Plants and animals in an environment. Some of these plants and animals might be sources of
food, clothing, or medicines for people.
Body burden :
The total amount of a substance in the body. Some substances build up in the body because they
are stored in fat or bone or because they leave the body very slowly.
CAP:
[see Community Assistance Panel.]
Cancer :
Any one of a group of diseases that occur when cells in the body become abnormal and grow or
multiply out of control.
Cancer risk :
A theoretical risk for getting cancer if exposed to a substance every day for 70 years (a lifetime
exposure). The true risk might be lower.
Carcinogen :
A substance that causes cancer.
Case study :
A medical or epidemiologic evaluation of one person or a small group of people to gather
information about specific health conditions and past exposures.
Case-control study :
A study that compares exposures of people who have a disease or condition (cases) with people
who do not have the disease or condition (controls). Exposures that are more common among the
cases may be considered as possible risk factors for the disease.
CAS registry number :
A unique number assigned to a substance or mixture by the American Chemical Society
Abstracts Service.
Central nervous system :
The part of the nervous system that consists of the brain and the spinal cord.
CERCLA:
[see Comprehensive Environmental Response, Compensation, and Liability Act of
1980]
Chronic :
Occurring over a long time [compare with acute].
Chronic exposure :
Contact with a substance that occurs over a long time (more than 1 year) [compare with acute
exposure and intermediate duration exposure]
Cluster investigation:
A review of an unusual number, real or perceived, of health events (for example, reports of
cancer) grouped together in time and location. Cluster investigations are designed to confirm case
reports; determine whether they represent an unusual disease occurrence; and, if possible, explore
possible causes and contributing environmental factors.
Community Assistance Panel (CAP) :
A group of people from a community and from health and environmental agencies who work
with ATSDR to resolve issues and problems related to hazardous substances in the community.
CAP members work with ATSDR to gather and review community health concerns, provide
information on how people might have been or might now be exposed to hazardous substances,
and inform ATSDR on ways to involve the community in its activities.
Comparison value (CV) :
Calculated concentration of a substance in air, water, food, or soil that is unlikely to cause
harmful (adverse) health effects in exposed people. The CV is used as a screening level during
the public health assessment process. Substances found in amounts greater than their CVs might
be selected for further evaluation in the public health assessment process.
Completed exposure pathway:
[see exposure pathway].
Comprehensive Environmental Response, Compensation, and Liability Act of 1980
(CERCLA) :
CERCLA, also known as Superfund, is the federal law that concerns the removal or cleanup of
hazardous substances in the environment and at hazardous waste sites. ATSDR, which was
created by CERCLA, is responsible for assessing health issues and supporting public health
activities related to hazardous waste sites or other environmental releases of hazardous
substances. This law was later amended by the Superfund Amendments and Reauthorization Act
(SARA).
Concentration :
The amount of a substance present in a certain amount of soil, water, air, food, blood, hair, urine,
breath, or any other media.
Contaminant :
A substance that is either present in an environment where it does not belong or is present at
levels that might cause harmful (adverse) health effects.
Delayed health effect :
A disease or an injury that happens as a result of exposures that might have occurred in the past.
Dermal :
Referring to the skin. For example, dermal absorption means passing through the skin.
Dermal contact :
Contact with (touching) the skin [see route of exposure].
Descriptive epidemiology :
The study of the amount and distribution of a disease in a specified population by person, place,
and time.
Detection limit :
The lowest concentration of a chemical that can reliably be distinguished from a zero
concentration.
Disease prevention :
Measures used to prevent a disease or reduce its severity.
Disease registry :
A system of ongoing registration of all cases of a particular disease or health condition in a
defined population.
DOD :
United States Department of Defense.
DOE :
United States Department of Energy.
Dose (for chemicals that are not radioactive):
The amount of a substance to which a person is exposed over some time period. Dose is a
measurement of exposure. Dose is often expressed as milligram (amount) per kilogram (a
measure of body weight) per day (a measure of time) when people eat or drink contaminated
water, food, or soil. In general, the greater the dose, the greater the likelihood of an effect. An
"exposure dose" is how much of a substance is encountered in the environment. An "absorbed
dose" is the amount of a substance that actually got into the body through the eyes, skin, stomach,
intestines, or lungs.
Dose (for radioactive chemicals) :
The radiation dose is the amount of energy from radiation that is actually absorbed by the body.
This is not the same as measurements of the amount of radiation in the environment.
Dose-response relationship :
The relationship between the amount of exposure [dose] to a substance and the resulting changes
in body function or health (response).
Environmental media :
Soil, water, air, biota (plants and animals), or any other parts of the environment that can contain
contaminants.
Environmental media and transport mechanism :
Environmental media include water, air, soil, and biota (plants and animals). Transport
mechanisms move contaminants from the source to points where human exposure can occur. The
environmental media and transport mechanism is the second part of an exposure pathway.
EPA :
United States Environmental Protection Agency.
Epidemiologic surveillance:
[see Public health surveillance].
Epidemiology :
The study of the distribution and determinants of disease or health status in a population; the
study of the occurrence and causes of health effects in humans.
Exposure :
Contact with a substance by swallowing, breathing, or touching the skin or eyes. Exposure may
be short-term [acute exposure], of intermediate duration, or long-term [chronic exposure].
Exposure assessment :
The process of finding out how people come into contact with a hazardous substance, how often
and for how long they are in contact with the substance, and how much of the substance they are
in contact with.
Exposure-dose reconstruction :
A method of estimating the amount of people's past exposure to hazardous substances. Computer
and approximation methods are used when past information is limited, not available, or missing.
Exposure investigation :
The collection and analysis of site-specific information and biologic tests (when appropriate) to
determine whether people have been exposed to hazardous substances.
Exposure pathway :
The route a substance takes from its source (where it began) to its end point (where it ends), and
how people can come into contact with (or get exposed to) it. An exposure pathway has five
parts: a source of contamination (such as an abandoned business); an environmental media and
transport mechanism (such as movement through groundwater); a point of exposure (such as a
private well); a route of exposure (eating, drinking, breathing, or touching), and a receptor
population (people potentially or actually exposed). When all five parts are present, the exposure
pathway is termed a completed exposure pathway.
Exposure registry :
A system of ongoing followup of people who have had documented environmental exposures.
Feasibility study :
A study by EPA to determine the best way to clean up environmental contamination. A number
of factors are considered, including health risk, costs, and what methods will work well.
Geographic information system (GIS) :
A mapping system that uses computers to collect, store, manipulate, analyze, and display data.
For example, GIS can show the concentration of a contaminant within a community in relation to
points of reference such as streets and homes.
Grand rounds :
Training sessions for physicians and other health care providers about health topics.
Groundwater :
Water beneath the earth's surface in the spaces between soil particles and between rock surfaces
[compare with surface water].
Half-life (t½) :
The time it takes for half the original amount of a substance to disappear. In the environment, the
half-life is the time it takes for half the original amount of a substance to disappear when it is
changed to another chemical by bacteria, fungi, sunlight, or other chemical processes. In the
human body, the half-life is the time it takes for half the original amount of the substance to
disappear, either by being changed to another substance or by leaving the body. In the case of
radioactive material, the half life is the amount of time necessary for one half the initial number
of radioactive atoms to change or transform into another atom (that is normally not radioactive).
After two half lives, 25% of the original number of radioactive atoms remain.
Hazard :
A source of potential harm from past, current, or future exposures.
Hazardous Substance Release and Health Effects Database (HazDat) :
The scientific and administrative database system developed by ATSDR to manage data
collection, retrieval, and analysis of site-specific information on hazardous substances,
community health concerns, and public health activities.
Hazardous waste :
Potentially harmful substances that have been released or discarded into the environment.
Health consultation :
A review of available information or collection of new data to respond to a specific health
question or request for information about a potential environmental hazard. Health consultations
are focused on a specific exposure issue. Health consultations are therefore more limited than a
public health assessment, which reviews the exposure potential of each pathway and chemical
[compare with public health assessment].
Health education :
Programs designed with a community to help it know about health risks and how to reduce these
risks.
Health investigation :
The collection and evaluation of information about the health of community residents. This
information is used to describe or count the occurrence of a disease, symptom, or clinical
measure and to evaluate the possible association between the occurrence and exposure to
hazardous substances.
Health promotion :
The process of enabling people to increase control over, and to improve, their health.
Health statistics review :
The analysis of existing health information (i.e., from death certificates, birth defects registries,
and cancer registries) to determine if there is excess disease in a specific population, geographic
area, and time period. A health statistics review is a descriptive epidemiologic study.
Indeterminate public health hazard :
The category used in ATSDR's public health assessment documents when a professional
judgment about the level of health hazard cannot be made because information critical to such a
decision is lacking.
Incidence :
The number of new cases of disease in a defined population over a specific time period [contrast
with prevalence].
Ingestion :
The act of swallowing something through eating, drinking, or mouthing objects. A hazardous
substance can enter the body this way [see route of exposure].
Inhalation :
The act of breathing. A hazardous substance can enter the body this way [see route of exposure].
Intermediate duration exposure :
Contact with a substance that occurs for more than 14 days and less than a year [compare with
acute exposure and chronic exposure].
In vitro :
In an artificial environment outside a living organism or body. For example, some toxicity testing
is done on cell cultures or slices of tissue grown in the laboratory, rather than on a living animal
[compare with in vivo].
In vivo :
Within a living organism or body. For example, some toxicity testing is done on whole animals,
such as rats or mice [compare with in vitro].
Lowest-observed-adverse-effect level (LOAEL) :
The lowest tested dose of a substance that has been reported to cause harmful (adverse) health
effects in people or animals.
Medical monitoring :
A set of medical tests and physical exams specifically designed to evaluate whether an
individual's exposure could negatively affect that person's health.
Metabolism :
The conversion or breakdown of a substance from one form to another by a living organism.
Metabolite :
Any product of metabolism.
mg/kg :
Milligram per kilogram.
mg/cm2:
Milligram per square centimeter (of a surface).
mg/m3:
Milligram per cubic meter; a measure of the concentration of a chemical in a known volume (a
cubic meter) of air, soil, or water.
Migration :
Moving from one location to another.
Minimal risk level (MRL) :
An ATSDR estimate of daily human exposure to a hazardous substance at or below which that
substance is unlikely to pose a measurable risk of harmful (adverse), noncancerous effects. MRLs
are calculated for a route of exposure (inhalation or oral) over a specified time period (acute,
intermediate, or chronic). MRLs should not be used as predictors of harmful (adverse) health
effects [see reference dose].
Morbidity :
State of being ill or diseased. Morbidity is the occurrence of a disease or condition that alters
health and quality of life.
Mortality :
Death. Usually the cause (a specific disease, a condition, or an injury) is stated.
Mutagen :
A substance that causes mutations (genetic damage).
Mutation :
A change (damage) to the DNA, genes, or chromosomes of living organisms.
National Priorities List for Uncontrolled Hazardous Waste Sites (National Priorities List or
NPL) :
EPA's list of the most serious uncontrolled or abandoned hazardous waste sites in the United
States. The NPL is updated on a regular basis.
National Toxicology Program (NTP):
Part of the Department of Health and Human Services. NTP develops and carries out tests to
predict whether a chemical will cause harm to humans.
No apparent public health hazard :
A category used in ATSDR's public health assessments for sites where human exposure to
contaminated media might be occurring, might have occurred in the past, or might occur in the
future, but where the exposure is not expected to cause any harmful health effects.
No-observed-adverse-effect level (NOAEL) :
The highest tested dose of a substance that has been reported to have no harmful (adverse) health
effects on people or animals.
No public health hazard :
A category used in ATSDR's public health assessment documents for sites where people have
never and will never come into contact with harmful amounts of site-related substances.
NPL:
[see National Priorities List for Uncontrolled Hazardous Waste Sites]
Physiologically based pharmacokinetic model (PBPK model) :
A computer model that describes what happens to a chemical in the body. This model describes
how the chemical gets into the body, where it goes in the body, how it is changed by the body,
and how it leaves the body.
Pica :
A craving to eat nonfood items, such as dirt, paint chips, and clay. Some children exhibit pica-related behavior.
Plume :
A volume of a substance that moves from its source to places farther away from the source.
Plumes can be described by the volume of air or water they occupy and the direction they move.
For example, a plume can be a column of smoke from a chimney or a substance moving with
groundwater.
Point of exposure :
The place where someone can come into contact with a substance present in the environment [see
exposure pathway].
Population :
A group or number of people living within a specified area or sharing similar characteristics
(such as occupation or age).
Potentially responsible party (PRP) :
A company, government, or person legally responsible for cleaning up the pollution at a
hazardous waste site under Superfund. There may be more than one PRP for a particular site.
ppb :
Parts per billion.
ppm :
Parts per million.
Prevalence :
The number of existing disease cases in a defined population during a specific time period
[contrast with incidence].
Prevalence survey :
The measure of the current level of disease(s) or symptoms and exposures through a
questionnaire that collects self-reported information from a defined population.
Prevention :
Actions that reduce exposure or other risks, keep people from getting sick, or keep disease from
getting worse.
Public availability session :
An informal, drop-by meeting at which community members can meet one-on-one with ATSDR
staff members to discuss health and site-related concerns.
Public comment period :
An opportunity for the public to comment on agency findings or proposed activities contained in
draft reports or documents. The public comment period is a limited time period during which
comments will be accepted.
Public health action :
A list of steps to protect public health.
Public health advisory :
A statement made by ATSDR to EPA or a state regulatory agency that a release of hazardous
substances poses an immediate threat to human health. The advisory includes recommended
measures to reduce exposure and reduce the threat to human health.
Public health assessment (PHA) :
An ATSDR document that examines hazardous substances, health outcomes, and community
concerns at a hazardous waste site to determine whether people could be harmed from coming
into contact with those substances. The PHA also lists actions that need to be taken to protect
public health [compare with health consultation].
Public health hazard :
A category used in ATSDR's public health assessments for sites that pose a public health hazard
because of long-term exposures (greater than 1 year) to sufficiently high levels of hazardous
substances or radionuclides that could result in harmful health effects.
Public health hazard categories :
Public health hazard categories are statements about whether people could be harmed by
conditions present at the site in the past, present, or future. One or more hazard categories might
be appropriate for each site. The five public health hazard categories are no public health hazard,
no apparent public health hazard, indeterminate public health hazard, public health hazard, and
urgent public health hazard.
Public health statement:
The first chapter of an ATSDR toxicological profile. The public health statement is a summary
written in words that are easy to understand. The public health statement explains how people
might be exposed to a specific substance and describes the known health effects of that
substance.
Public health surveillance:
The ongoing, systematic collection, analysis, and interpretation of health data. This activity also
involves timely dissemination of the data and use for public health programs.
Public meeting :
A public forum with community members for communication about a site.
Radioisotope :
An unstable or radioactive isotope (form) of an element that can change into another element by
giving off radiation.
Radionuclide :
Any radioactive isotope (form) of any element.
RCRA:
[see Resource Conservation and Recovery Act (1976, 1984)]
Receptor population :
People who could come into contact with hazardous substances [see exposure pathway].
Reference dose (RfD) :
An EPA estimate, with uncertainty or safety factors built in, of the daily lifetime dose of a
substance that is unlikely to cause harm in humans.
Registry :
A systematic collection of information on persons exposed to a specific substance or having
specific diseases [see exposure registry and disease registry].
Remedial investigation :
The CERCLA process of determining the type and extent of hazardous material contamination at
a site.
Resource Conservation and Recovery Act (1976, 1984) (RCRA):
This Act regulates management and disposal of hazardous wastes currently generated, treated,
stored, disposed of, or distributed.
RFA :
RCRA Facility Assessment. An assessment required by RCRA to identify potential and actual
releases of hazardous chemicals.
RfD:
[see reference dose]
Risk :
The probability that something will cause injury or harm.
Risk reduction :
Actions that can decrease the likelihood that individuals, groups, or communities will experience
disease or other health conditions.
Risk communication :
The exchange of information to increase understanding of health risks.
Route of exposure :
The way people come into contact with a hazardous substance. Three routes of exposure are
breathing [inhalation], eating or drinking [ingestion], or contact with the skin [dermal contact].
Safety factor:
[see uncertainty factor]
SARA:
[see Superfund Amendments and Reauthorization Act]
Sample :
A portion or piece of a whole. A selected subset of a population or subset of whatever is being
studied. For example, in a study of people the sample is a number of people chosen from a larger
population [see population]. An environmental sample (for example, a small amount of soil or
water) might be collected to measure contamination in the environment at a specific location.
Sample size :
The number of units chosen from a population or an environment.
Solvent :
A liquid capable of dissolving or dispersing another substance (for example, acetone or mineral
spirits).
Source of contamination :
The place where a hazardous substance comes from, such as a landfill, waste pond, incinerator,
storage tank, or drum. A source of contamination is the first part of an exposure pathway.
Special populations :
People who might be more sensitive or susceptible to exposure to hazardous substances because
of factors such as age, occupation, sex, or behaviors (for example, cigarette smoking). Children,
pregnant women, and older people are often considered special populations.
Stakeholder :
A person, group, or community who has an interest in activities at a hazardous waste site.
Statistics :
A branch of mathematics that deals with collecting, reviewing, summarizing, and interpreting
data or information. Statistics are used to determine whether differences between study groups
are meaningful.
Substance :
A chemical.
Substance-specific applied research :
A program of research designed to fill important data needs for specific hazardous substances
identified in ATSDR's toxicological profiles. Filling these data needs would allow more accurate
assessment of human risks from specific substances contaminating the environment. This
research might include human studies or laboratory experiments to determine health effects
resulting from exposure to a given hazardous substance.
Superfund:
[see Comprehensive Environmental Response, Compensation, and Liability Act of
1980 (CERCLA) and Superfund Amendments and Reauthorization Act (SARA)
Superfund Amendments and Reauthorization Act (SARA) :
In 1986, SARA amended the Comprehensive Environmental Response, Compensation, and
Liability Act of 1980 (CERCLA) and expanded the health-related responsibilities of ATSDR.
CERCLA and SARA direct ATSDR to look into the health effects from substance exposures at
hazardous waste sites and to perform activities including health education, health studies,
surveillance, health consultations, and toxicological profiles.
Surface water :
Water on the surface of the earth, such as in lakes, rivers, streams, ponds, and springs [compare
with groundwater].
Surveillance:
[see public health surveillance]
Survey :
A systematic collection of information or data. A survey can be conducted to collect information
from a group of people or from the environment. Surveys of a group of people can be conducted
by telephone, by mail, or in person. Some surveys are done by interviewing a group of people
[see prevalence survey].
Synergistic effect :
A biologic response to multiple substances where one substance worsens the effect of another
substance. The combined effect of the substances acting together is greater than the sum of the
effects of the substances acting by themselves [see additive effect and antagonistic effect].
Teratogen :
A substance that causes defects in development between conception and birth. A teratogen is a
substance that causes a structural or functional birth defect.
Toxic agent :
Chemical or physical (for example, radiation, heat, cold, microwaves) agents that, under certain
circumstances of exposure, can cause harmful effects to living organisms.
Toxicological profile :
An ATSDR document that examines, summarizes, and interprets information about a hazardous
substance to determine harmful levels of exposure and associated health effects. A toxicological
profile also identifies significant gaps in knowledge on the substance and describes areas where
further research is needed.
Toxicology :
The study of the harmful effects of substances on humans or animals.
Tumor :
An abnormal mass of tissue that results from excessive cell division that is uncontrolled and
progressive. Tumors perform no useful body function. Tumors can be either benign (not cancer)
or malignant (cancer).
Uncertainty factor :
Mathematical adjustments for reasons of safety when knowledge is incomplete. For example,
factors used in the calculation of doses that are not harmful (adverse) to people. These factors are
applied to the lowest-observed-adverse-effect-level (LOAEL) or the no-observed-adverse-effect-level (NOAEL) to derive a minimal risk level (MRL). Uncertainty factors are used to account for
variations in people's sensitivity, for differences between animals and humans, and for
differences between a LOAEL and a NOAEL. Scientists use uncertainty factors when they have
some, but not all, the information from animal or human studies to decide whether an exposure
will cause harm to people [also sometimes called a safety factor].
Urgent public health hazard :
A category used in ATSDR's public health assessments for sites where short-term exposures (less
than 1 year) to hazardous substances or conditions could result in harmful health effects that
require rapid intervention.
Volatile organic compounds (VOCs) :
Organic compounds that evaporate readily into the air. VOCs include substances such as
benzene, toluene, methylene chloride, and methyl chloroform.
For more information on the work of ATSDR, please contact:
Office of Policy and External Affairs
Agency for Toxic Substances and Disease Registry
1600 Clifton Road, N.E. (MS E-60)
Atlanta, GA 30333
Telephone: (404) 498-0080
APPENDIX B: ATSDR'S ASSESSMENT METHODOLOGY AND COMPARISON VALUES
Human Exposure Pathway Evaluation and the Use of ATSDR Comparison Values
The Agency for Toxic Substances and Disease Registry (ATSDR) assesses a site by evaluating
the level of exposure in potential or completed exposure pathways. An exposure pathway is the
way chemicals may enter a person's body to cause a health effect. It includes all the steps
between the release of a chemical and the population exposed, including: (1) a chemical release
source, (2) chemical movement, (3) a place where people can come into contact with the
chemical, (4) a route of human exposure, and (5) a population that could be exposed. In this
assessment, ATSDR evaluates chemicals in environmental media that people residing near a site
may consume, inhale, or contact.
Health assessors use comparison values (CVs) as screening tools to evaluate environmental data
that is relevant to the exposure pathways. CVs represent media-specific contaminant
concentrations that are used to select contaminants for further evaluation to determine the
possibility of adverse health effects. CVs used in this document include ATSDR's environmental
media evaluation guide (EMEG) and cancer risk evaluation guide (CREG). CVs are derived from
available health guidelines, such as ATSDR's minimal risk levels and EPA's cancer slope factor.
Category of CVs used in this public health assessment are described below.
Cancer Slope Factor (CSF):
Usually derived from dose-response models and expressed in mg/kg/day, CSFs
describe the inherent potency of carcinogens and estimate an upper limit on the
likelihood that lifetime exposure to a particular chemical could lead to excess cancer
deaths.
Cancer Risk Evaluation Guide (CREG):
Estimated contaminant concentrations that would be expected to cause no more than
one excess cancer in a million (10-6) persons exposed over a 70-year life span.
ATSDR's CREGs are calculated from EPA's cancer potency factors.
EPA Region III Risk-Based Concentration:
EPA combines reference doses and carcinogenic potency slopes with "standard"
exposure scenarios to calculate risk-based concentrations, which are chemical
concentrations corresponding to fixed levels of risk (i.e., a hazard quotient of 1, or
lifetime cancer risk of 10-6, whichever occurs at a lower concentration) in water, air,
fish tissue, and soil.
Lowest Observed Adverse Effect Level (LOAEL):
The lowest dose of a chemical that produced an adverse-effect when it was
administered to animals in a toxicity study.
Maximum Contaminant Level (MCL):
The MCL is the drinking water standard established by EPA. It is the maximum
permissible level of a contaminant in water that is delivered to a free-flowing outlet.
MCLs are considered protective of human health over a lifetime (70 years) for
individuals consuming 2 liters of water per day.
Minimal Risk Levels (MRL):
MRLs are estimates of daily human exposure to a chemical (i.e., doses expressed in
mg/kg/day) that are unlikely to be associated with any appreciable risk of deleterious
noncancer effects over a specified duration of exposure. MRLs are calculated using
data from human and animal studies and are reported for acute (< 14 days),
intermediate (15-364 days), and chronic (> 365 days) exposures. MRLs are published
in ATSDR Toxicological Profiles for specific chemicals.
The derivation of a CV uses conservative exposure assumptions, resulting in values that are
much lower than exposure concentrations observed to cause adverse health effects; thus, insuring
the CVs are protective of public health in essentially all exposure situations. That is, if the
concentrations in the exposure medium are less than the CV, the exposures are not of health
concern and no further analysis of the pathway is required. However, while concentrations below
the CV are not expected to lead to any observable health effect, it should not be inferred that a
concentration greater than the CV will necessarily lead to adverse effects. Depending on site-specific environmental exposure factors (for example, duration of exposure) and activities of
people that result in exposure (time spent in area of contamination), exposure to levels above the
CV may or may not lead to a health effect. Therefore, ATSDR's CVs are not used to predict the
occurrence of adverse health effects.
The CVs used in this evaluation are defined as follows: The CREG is a concentration at which
excess cancer risk is not likely to exceed one case of cancer in a million persons exposed over a
lifetime. The CREG is a very conservative CV that is used to estimate cancer risk. Exposure to a
concentration equal to or less than the CREG is defined as an insignificant risk and is an
acceptable level of exposure over a lifetime. The risk from exposure is not considered as a
significant risk unless the exposure concentration is approximately 10 times the CREG and
exposure occurs over several years. The EMEG is a concentration at which daily exposure for a
lifetime is unlikely to result in adverse noncancerous effects.
Elements of a Completed Exposure Pathway
In evaluating public health hazards, ATSDR first tries to determine exposure in the past, present,
and future. ATSDR does this by carefully evaluating the elements of an exposure pathway that
might lead to human exposure. These elements include: (1) a source of site-related
contamination, such as drums or waste pits; (2) an environmental medium in which the
contaminants might be present or from which they might migrate, such as groundwater or soil;
(3) points of human exposure, such as drinking water wells or gardens; (4) routes of exposure,
such as breathing, eating, drinking, or touching a substance containing the contaminant; and (5) a
receptor population. (Figure 3 explains the exposure pathway evaluation in more detail.) ATSDR
then identifies an exposure pathway as completed or potential, or eliminates that pathway from
further evaluation. A completed exposure pathway exists in the past, present, or future if all
elements of human exposure link the contaminant source to a receptor population. A potential
pathway is one that ATSDR cannot rule out, even though we cannot find one of the necessary
elements.
If a completed or potential exposure pathway exists, ATSDR then considers whether any
chemicals were present, are present, or are expected to become present.
Selecting Chemicals for Further Evaluation
Identifying chemicals for further evaluation is a process that requires ATSDR to examine
contaminant concentrations at the site, the quality of environmental sampling data, and the
potential for human exposure. A thorough review of each of these issues is required to accurately
select chemicals in the site-specific human exposure pathway. The following text describes the
selection process.
In the first step of the chemical selection process, the maximum contaminant concentrations are
compared directly to health-based CVs. ATSDR considers site-specific exposure factors to
ensure selection of appropriate health CVs. If the maximum concentration reported for a
chemical is less than the health CV, ATSDR concludes that exposure to that chemical is not of
public health concern; therefore, no further data review is required for that chemical. However, if
the maximum concentration is greater than the health CV, the chemical is selected for additional
data review. In addition, any chemicals detected that do not have relevant health CVs are also
selected for additional data review.
CVs have not been developed for some contaminants, and, based on new scientific information
other CVs may be determined to be inappropriate for the specific type of exposure. In those
cases, the contaminants are included for further review if current scientific information indicates
exposure to those contaminants may be of public health concern.
The next step of the process requires a more in-depth review of data for each of the contaminants
selected. Factors used in the selection of the chemicals includes the number of samples with detections above the minimum detection limit, the number of samples with detections above an acute or chronic health CV, and the potential for exposure at the monitoring location.
APPENDIX C: ATSDR'S RESPONSE TO PUBLIC COMMENTS
The Agency for Toxic Substances and Disease Registry released the Louisiana Army
Ammunition Plant (LAAP) Public Health Assessment (PHA) for public review and comment on
January 23, 2003. The public comment period was announced in a press release on January 30,
2003. Copies of the PHA were made available for review at the Commanders Office at LAAP.
The PHA was also sent to state and federal agencies.
ATSDR received the following comments during the public comment period (January 23 to
February 23, 2003).
Comment: The commenter states that ATSDR's conclusion in
the PHA that "no threat" exists is inaccurate because data for private wells
south of the LAAP southern boundary are lacking. Because of potential exposure
via private wells, the commenter suggests that ATSDR modify the conclusion
to reflect a level of risk that is "indeterminate."
Response: The commenter questions ATSDR's conclusions of
"no threat" to public health given the lack of private well data south of
LAAP's boundary. ATSDR emphasizes that the goal of ATSDR's PHA is to help
put environmental data into meaningful public health perspective for the community.
That is, we try to answer the question of whether environmental exposure occurred
and whether any such exposure might be harmful. One of the challenges we face
is to evaluate potential health hazards given the lack of available data.
In some cases, the indeterminate public health hazard category is used for
sites when a professional judgement on the level of health hazard cannot be
made because information critical to such a decision is lacking. When possible,
however, ATSDR finds it most helpful to the community to use available information
about site conditions and our best professional judgement to draw conclusions
about human exposures that could affect the community.
Following this approach, ATSDR believes it had sufficient information to
address the question of whether or not contaminants from LAAP were likely
to have an adverse impact on public health. That is, ATSDR's evaluation of
potential public health hazards from LAAP was based on a relatively large
set of groundwater monitoring results. It considered the results of many groundwater
samples collected at locations at and downgradient of LAAP over a time frame
that spans nearly 15 years. Studying the nature and extent of groundwater
contaminant levels helped us understand groundwater quality beneath the site
and south of the plant boundary, where local residents possibly rely on private
wells. Detected groundwater contaminants in monitoring wells south of the
boundary suggest that contaminants migrated in that direction, but were not
present at harmful levels. While one account suggests that two off-site wells
sampled in 1987 had RDX at levels above ATSDR's CV, these findings were considered
anomalies because elevated levels were not detected upon follow-up sampling
of the affected wells or in the monitoring wells lying between the suspected
source (BG-8) and the site boundary. No exposures are occurring now as contamination
at levels above ATSDR CVs have not been detected beyond the plant's boundary
since 1994. Considering the evidence collected from many sampling events over
time that show groundwater contamination in the LAAP area did not reach levels
of health concern, ATSDR concluded that no health threat exists.
Comment: The commenter recommends regular testing of nearby
private wells. The commenter asserts that it is erroneous to conclude that
the levels in off-site private drinking water wells will be identical to detected
contaminant levels in groundwater monitoring wells.
Response: ATSDR's assessment of potential contamination
of groundwater/drinking water supplies south of LAAP is based on information
presented in environmental investigation documents and well monitoring results.
LAAP detected explosive compound concentrations in boundary wells and off-site
monitoring wells during 1984-1989 sampling south of Area P and BG-8. These
levels were generally low and far below ATSDR CVs. Off-post contaminant migration
to the south was substantially reduced by 1994. Results from recent monitoring
indicate that contamination is currently contained within the plant boundaries,
thus providing evidence that contamination is not currently reaching populated
areas that might rely on private wells. LAAP is also conducting removal and
remedial actions that have and should continue to limit possible off-site
migration. Given that ongoing groundwater monitoring along the southern boundary
of the site shows that the contamination is contained within the plant boundaries,
ATSDR does not believe that monitoring of private wells that could draw from
groundwater in the vicinity of the southern plant boundary is necessary at
this time. If information should become available in the future to suggest
that off-plant migration occurs, then the Army should reevaluate the extent
of its monitoring program at that time.
Comment: The commenter states that ATSDR describes 1,3-dinitrobenzene
(1,3-DNB) and 1,3,5-trinitrobenzene(1,3,5-TNB) as the "most mobile, toxic,
and frequently detected chemicals in surface soil at LAAP." The commenter
then recommends that off-site groundwater and drinking water monitoring include
testing for degradation products, such as 1,3-DNB associated with the contaminants
of concern.
Response: The sentence quoted by the commenter was taken
from the following paragraph in the PHA. "Results indicated that RDX was present
at the highest concentrations at the Area P (above 100 ppm), BG-8 Landfill/Lagoon
(up to 48.32 ppm) and the BG-5 Landfill former burning ground (up to 100 ppm).
Other explosive compounds of concern detected at these AOCs include 1,3-dinitrobenzene,
1,3,5-trinitrobenzene, and/or 2,4,6 trinitrotoluene (ESE 1996). These compounds
represent the most mobile, toxic, and frequently detected chemicals in surface
soil at LAAP." The last sentence about mobility and frequency of detection
refers to explosive compounds in general detected at LAAP.
Groundwater at and downgradient of LAAP was typically tested for a panel
of nine explosive compounds that includes 1,3-DNB and 1,3,5-TNB. Starting
in the late 1980s, LAAP sampled groundwater at four off-site monitoring wells
(two south of Area P and two south of BG-8). The explosive compound 1,3,5-TNB
was found at trace levels in an off-post monitoring well located south of
the Area P and BG-8 area. The 1,3,5-TNB concentrations, ranging from 0.369
to 1.71 part per billion (ppb), were less than ATSDR's comparison value (CV)
of 5 ppb for that compound. Concentrations of explosive compounds from Area
P and BG-8 in groundwater along the southern boundary have decreased over
time. More recent sampling in 1991, 1995, and 1998 found lower levels of explosive
compounds in wells along the southern fence line. No contaminants were reported
in any monitoring wells beyond the plant's southern boundary since 1991.
Drinking water supplied by the Village Water Supply and the Doyline Water
Supply is also routinely sampled for the same nine explosive compounds that
are in local groundwater. Testing has shown sporadic detections of explosive
compounds in the drinking water wells, but at levels below ATSDR CVs. Retests
of the affected well showed no evidence of explosive compounds in the well
water. The drinking water well field was most recently sampled in 1997 and
2001, at which time no explosive compounds were detected. LAAP will continue
to monitor off-site groundwater quality to identify and diminish the threat
of potential health hazards. The U.S. Army Corp of Engineers will also continue
to sample Doyline's drinking water supply every year or every other year for
at least another 10 years, in accordance with Superfund guidance.
Comment: The commenter suggests that existing records do
not support ATSDR's finding that campers attending National Guard Camps are
not likely to contact contaminated soil.
Response: A portion of the former administrative area at
LAAP is now used by the National Guard for a Youth Challenge Camp. According
to site documentation reviewed by ATSDR, the Army never used administrative
property to store, process, or dispose of hazardous materials. Campers attending
the National Guard Camp, therefore, are not likely to contact contaminated
soil within the camp facility. Even if campers trespass away from the camp,
they are unlikely to contact harmful levels of soil contaminants for several
reasons. First, access to soil at former operational areas is limited by perimeter
fencing and/or covered surfaces (e.g., vegetative growth, pavement). Second,
contaminated surface soil has been removed (such as at Area P) or the contaminants
exist at levels not high enough to cause health hazards from brief and infrequent
contact associated with trespassing. Considering this information, ATSDR finds
no reasons to believe that campers will contact soil contaminants at levels
known to be associated with adverse health effects.
Comment: The commenter recommends that ATSDR reassess its
conclusion about no hazards from future uses of LAAP property, asserting that
non-industrial future uses of the site are possible.
Response: ATSDR concluded in its PHA that no harmful exposures
should occur at LAAP in the future. When drawing its conclusion about the
potential future exposures, ATSDR considered the following factors:
Measures implemented to reduce potential exposure with contaminated
material. The Army has under taken remedial measures that reduce the
likelihood of potential exposures at LAAP in the future. These measures included
removal of soils and structures from some of the most highly contaminated
portions of the property and installation of a barrier to prevent unwanted
access. As an example, an interim remedial action at Area P from 1987 to 1990
involved excavation of and incineration of 100,000 tons of explosives-contaminated
soil and treated more than 50 million gallons of wastewater from the lagoons.
Sampling of the excavated area confirmed that the soil with HMX and RDX above
100 ppm had been removed. The excavated lagoons were backfilled with the treated
soil, capped, and revegetated under RCRA. The Army installed a barbed-wire
fence around the Area P lagoon cap and regularly monitors the cap to ensure
its integrity. Signs posted around the lagoons read "Area P Decontamination
Area."
Regulations and conditions governing future property transfers.
The former operational areas at LAAP will remain industrial and will not be
used for residential or agricultural uses in the future. Existing Army regulations
make the sale of the industrial section unlikely. If land at LAAP is sold
or transferred, Superfund guidance requires that each deed must specify measures
that must be taken to ensure that public health and the environment will be
adequately protected. Any measures outlined in the deed must be completed
before the date of property transfer.
Locations of areas of concern. Overall, LAAP covers a large tract
of land. It spans across 15,000 acres, measuring 9 miles east to west and
3 miles north to south. Only about 20% (roughly 3,000 acres) of this land,
however, was used at any time to support mission-related operations or was
associated with site releases. The remaining portion is woodland (79%, or
about 11,800 acres ) or supported non-industrial administrative-related services
(less than 1%,or 150 acres). Therefore, a large portion of this land is unaffected
by former operations and appears free of site-related health hazards. As discussed
in the PHA, about 3.5 acres of former administrative land in Area B at LAAP
was transferred for use as a minimum-to-medium security prison facility. This
portion of Area B was used neither for storage nor production of chemicals
or munitions. Despite the lack of involvement in LAAP munition production
operations, LAAP performed several investigations to characterize environmental
conditions at the property. ATSDR reviewed the results of these available
data, finding that contaminants from former site operations did not exist
in environmental media, such as groundwater, soil, or air, at levels that
could pose harm to future occupants of the property. Other nonindustrial property
at LAAP may be transferred or sold in the future following similar investigations.
Comment: The commenter could not find records of public
meetings or other forums sponsored by ATSDR designed to gather information
and gain an understanding of the community's health concerns. The commenter
suggested that ATSDR relied on concerns cited in the Community Relations Plan
prepared by LAAP and voiced at technical review committee meetings.
Response: Community involvement varies from site to site,
dependent upon such factors as identified hazards and the level of community
interest and concern. Strategies involving the community at one site may not
necessarily be needed or effective at another site. That is why ATSDR approaches
community involvement on a site-specific basis.
As an initial step in the PHA process at LAAP, ATSDR gathered available
information about the site and characteristics of the community from the Army,
as well as from the U.S. Environmental Protection Agency (EPA) and Louisiana
Department of Environmental Quality (LADEQ). Under a Federal Facilities Agreement
(FFA), EPA and LADEQ oversee Army environmental investigation activities at
LAAP, including community involvement activities. According to the EPA, the
community showed little interest in LAAP and appeared "unconcerned" about
the site. Information gathered during ATSDR site visits (1989, 1991, and 2001)
also failed to identify any specific health concerns or heighten our awareness
of community interest in the site. In addition to gathering information at
our visits–and to gain some perspective on possible community concerns–ATSDR
reviewed documented health concerns contained in LAAP's community involvement
plan. The community involvement plan is the responsibility of the Army (with
oversight by EPA and LDEQ) as outlined in the FFA. ATSDR also reviewed issues
raised by members of the technical review committee for LAAP. An evaluation
of these issues is presented in the Community
Health Concern section of the PHA.
Overall, ATSDR's evaluation of the LAAP site presented in the PHA found
no threat to the health of the local community. As a way to involve the community
in ATSDR's health associated activities, ATSDR released its findings in the
PHA for public review and comment on January 23, 2003. Press coverage about
the PHA appeared in the local paper on January 30, 2003. ATSDR received this
one set of comments on the public comment release draft.
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