Past exposure to contaminants in soil at most areas was too small to result
in adverse health effects. The levels of TNT and lead at the TNT Burial Site
and lead at the James River Beachfront Area could theoretically have increased
the risk of adverse health effects, but regular contact with the highest detected
levels would have been necessary.
Although contaminant levels have been decreased through site cleanup activities,
some remaining elevated levels of TNT and lead could pose a risk in the future
if small children have more regular contact with soil, as could happen if the
area is developed for residential use.
Past exposures to contaminants in TCC drinking water were too low to result
in adverse health effects. No evidence that other site groundwater was or is
currently used for drinking was found. Untreated groundwater is unsuitable for
future drinking water purposes because of elevated levels of metals in groundwater
at the Dominion Lands area and elevated metals and TNT in groundwater at the
TNT Burial Site on TCC Property.
No adverse health effects are expected from past, present, or future exposure
to surface water or sediments, from eating fish caught at TCC Lake or J-Lake,
or from drinking private well water in the Respass Beach Community.
Physical hazards are posed by the remaining open brick vaults, the World
War II pier, and debris surfacing at beachfront areas.
If appropriate clearance procedures are followed and enforceable land use
controls are put in place, the risk of accidents involving ordnance will be
minimized. However, a small chance of encountering ordnance continues to exist.
VI. RECOMMENDATIONS
Continue cleanup activities to address contaminants in soil at the TNT Burial
Site.
If areas are developed for residential use, test soils for lead and clean
up if necessary.
Do not use groundwater at the site for drinking water, unless the water is
fully characterized and treated to ensure that drinking water standards are
met.
Address physical hazards by filling in open brick vaults, removing or restricting
access to the World War II pier, and cleaning up debris or keeping access restrictions
in place at the beachfront areas.
Follow ordnance and explosives clearance procedures for expected future land
use and set up appropriate, enforceable land use controls. Educate potential
future landowners and occupants about hazards posed by ordnance materials and
procedures to follow if ordnance is encountered.
VII. PUBLIC HEALTH ACTION PLAN
The Public Health Action Plan for the site contains a description of actions
that have been or will be taken by ATSDR and/or other government agencies at
the site. The purpose of the Public Health Action Plan is to ensure that this
public health assessment not only identifies public health hazards, but also
provides a plan of action designed to mitigate and prevent adverse human health
effects resulting from exposure to hazardous substances in the environment.
Included is a commitment on the part of ATSDR to follow up on this plan to ensure
its implementation. The public health actions that have been completed are as
follows:
Before the site was proposed to the NPL, ATSDR published two health consultations
evaluating public health implications of possible exposure to TCC's well water
and the James River Beachfront Landfill soil.
ATSDR conducted two site visits to verify site conditions and gather pertinent
information and data for the site.
ATSDR held a public availability session to gather health concerns from the
surrounding community.
The public health actions to be implemented follow:
EPA and ACE will continue investigating and cleaning up the site, as necessary.
ATSDR will continue to work with the federal and state environmental agencies
and review the results of future investigations, as necessary.
Planned Public Health Actions:
ATSDR will reevaluate and expand this plan when necessary. New environmental,
toxicological, or health outcome data or the results of implementing the above
proposed actions could result in the need for additional actions at this site.
VIII. PUBLIC COMMENTS
This public health assessment (PHA) was available for public review and comment
at the Portsmouth Campus Library of Tidewater Community College in Portsmouth,
Virginia and at the offices of the Norfolk Corps of Engineers on Front Street
in Norfolk, Virginia from December 1, 2003 to January 20, 2004. The document
was also available for viewing or downloading from the ATSDR web site.
The public comment period was announced in local newspapers. The public health
assessment was sent to members of the FNOD RAB; private citizens; and staff
in Virginia DEQ, ACE, and EPA.
Comments were received from a member of the RAB. They can be found in Appendix B, along with ATSDR's responses to them.
IX. ATSDR SITE TEAM
Authors of Public Health Assessment:
Jill Dyken, PhD, PE
Environmental Health Scientist
Division of Health Assessment and Consultation
Agency for Toxic Substances and Disease Registry
Barbara Cooper, MSPH
Environmental Health Scientist
Division of Health Assessment and Consultation
Agency for Toxic Substances and Disease Registry
Other Site Team Members:
Tom Stukas
Regional Representative, Region III
Office of Regional Operations
Agency for Toxic Substances and Disease Registry
Maria Teran-Maciver
Community Involvement Specialist
Division of Health Assessment and Consultation
Agency for Toxic Substances and Disease Registry
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APPENDIX A: EXPLANATION OF EVALUATION PROCESS
Screening Process
In evaluating these data, ATSDR used comparison values (CVs) to determine which
chemicals to examine more closely. CVs are the health-based thresholds for contaminant
concentrations found in a specific media (air, soil, or water). They are used
in the selection of contaminants for further evaluation. A CV incorporates assumptions
about daily exposure to a chemical and the standard amount of air, water, and
soil that someone might inhale or ingest each day.
A CV represents a concentration below which no known or anticipated adverse
human health effects are expected to occur. Different CVs are developed for
cancer and noncancer health effects. Noncancer levels are based on valid toxicologic
studies for a chemical, with appropriate safety factors included, and the assumption
that small children (22 pounds or less) and adults are exposed every day. Cancer
levels are based on a one-in-one-million excess cancer risk for an adult eating
contaminated soil or drinking contaminated water every day for 70 years. For
chemicals for which both cancer and noncancer levels exist, ATSDR uses the lower
of the levels to be protective of human health. However, exceeding a CV does
not mean that health effects will occur; it merely means that more evaluation
is needed.
The CVs used in the evaluation in this document are listed below:
Environmental Media Evaluation Guides (EMEGs) are estimated contaminant concentrations
in a media at which noncarcinogenic health effects are unlikely. EMEGs are derived
from the Agency for Toxic Substances and Disease Registry's (ATSDR) minimal
risk level (MRL).
Cancer Risk Evaluation Guides (CREGs) are estimated contaminant concentrations
that would be expected to cause no more than one additional excess cancer in
one million persons exposed over a lifetime. CREGs are calculated from the U.S.
Environmental Protection Agency's (EPA) cancer slope factors (CSFs).
Reference Media Evaluation Guides (RMEGs) are estimated contaminant
concentrations in a media at levels at which noncarcinogenic health effects
are unlikely. RMEGs are derived from EPA's reference dose (RfD).
Region 9 Preliminary Remediation Goals (R9 PRGs) are the estimated contaminant
concentrations in a media at which carcinogenic or noncarcinogenic health effects
are unlikely. The PRGs used in this PHA were derived by use of provisional reference
doses or CSFs calculated by EPA's Region 9 toxicologists and were last updated
in October 2002.
Region 3 Risk-based Concentrations (R3 RBCs) are the estimated contaminant
concentrations in a media at which carcinogenic or noncarcinogenic health effects
are unlikely. The RBCs used in this PHA were derived by use of provisional reference
doses or CSFs calculated by EPA's Region 3 toxicologists and were last updated
in October 2003.
EPA Action Levels (ALs) are the estimated contaminant concentrations in water
at which additional evaluation is needed to determine whether action is required
to eliminate or reduce exposure. Action levels can be based on mathematical
models.
EPA Soil Screening Levels (SSLs) are estimated contaminant concentrations in
soil at which additional evaluation is needed to determine if action is required
to eliminate or reduce exposure.
World Health Organization guidelines (WHO) are guidelines published by the
World Health Organization for drinking water quality.
Some CVs may be based on different durations of exposure. Acute duration
is defined as exposure lasting 14 days or less. Intermediate duration
exposure lasts between 15 and 364 days, and chronic exposures last one
year or more. Comparison values based on chronic exposure studies are used whenever
available. If an intermediate or acute comparison value is used, it is denoted
with a small i or a before the CV (e.g., iEMEG refers to the intermediate
duration EMEG).
Determination of Exposure Pathways
ATSDR identifies human exposure pathways by examining environmental and human
components that might lead to contact with COCs. A pathway analysis considers
five principal elements: a source of contamination, transport through an environmental
medium, a point of exposure, a route of human exposure, and an exposed population.
Completed exposure pathways are those for which the five elements are evident;
such pathways indicate that exposure to a contaminant has occurred in the past,
is now occurring, or will occur in the future. Potential exposure pathways are
those for which exposure seems possible, but one or more of the elements is
not clearly defined. Potential pathways indicate that exposure to a contaminant
could have occurred in the past, could be occurring now, or could occur in the
future. It should be noted that the identification of an exposure pathway does
not imply that health effects will occur. Exposures might or might not be substantive.
Therefore, even if exposure has occurred, is now occurring, or is likely to
occur in the future, human health effects might not result.
ATSDR reviewed site history, information on site activities, and the available
sampling data. On the basis of this review, ATSDR identified numerous exposure
pathways that warranted consideration.
Evaluation of Public Health Implications
The next step is to consider those contaminants present at levels above the
CVs and further identify which chemicals and exposure situations are likely
to be a health hazard. Child and adult exposure doses are calculated for the
site-specific exposure scenario, using ATSDR's assumptions about who goes on
the site and how often they contact the site contaminants. The exposure dose
is the amount of a contaminant that gets into a person's body. Following is
a brief explanation of how ATSDR calculated the estimated exposure doses for
the site.
Soil Ingestion
Exposure doses for ingestion of contaminants present in soil were calculated
by use of the maximum concentration measured in soil, in milligrams per kilogram
(mg/kg), or parts per million (ppm). This maximum concentration is then multiplied
by the soil ingestion rate for adults or teenagers (100 mg/day) or children
(200 mg/day). For occasional recreational exposure, the multiplication product
was divided by the average weight for an adult, 70 kg (154 pounds), or for a
10-year-old child, 36 kg (80 pounds). The resulting dose was then multiplied
by a factor of 208/365, because the exposure was assumed to occur on average
four times a week throughout the year. For exposure of college students and
faculty, the body weights used were 70 kg (154 pounds) for adults and 50 kg
(110 pounds) for older teenagers, and the exposure factor was 240/365 (5 days
a week for 48 weeks out of the year). For child soccer players, the assumed
weight was 36 kg and the exposure factor was 78/365 (3 days a week for 26 weeks
out of the year). For the purpose of estimating residential exposures, the child
weight was 10 kg (22 pounds) for a 1-year-old child and the exposure factor
was 1 to account for exposure throughout the year.
Groundwater Ingestion
For past exposure to contaminants in the TCC drinking water wells, the maximum
detected groundwater concentration was multiplied by an ingestion rate of 1.5
liters per day (L/day) for adults or 0.75 L/day for teenagers (75% of the daily
dose was assumed to occur on campus). The result was divided by the average
weight of an adult, 70 kg (154 pounds) or of an older teenager, 50 kg (110 pounds).
The result was multiplied by an exposure factor of 350/365, because exposure
was assumed to occur 350 days out of the year. For past, present, and potential
future residential exposure to contaminants in groundwater, the drinking water
ingestion rate used was 2 L/day for adults and 1 L/day for children. The average
body weight was 70 kg (154 pounds) for adults and 10 kg (22 pounds) for children,
and the exposure factor was 1 to account for year-round exposure. For the purpose
of estimating future exposures to groundwater contaminants by workers, only
adults were considered to be exposed, the ingestion rate was 1.5 L/day, and
the exposure factor was 250/365, because exposure was assumed to occur 5 days
a week for 50 weeks out of the year.
Surface Water Ingestion
Exposure doses for surface water ingestion were calculated by use of the maximum
concentration for a surface water contaminant, in milligrams per liter (mg/L).
This maximum concentration was then multiplied by an incidental surface water
ingestion rate of 0.2 liter/day for adults or 0.1 liter/day for children. These
ingestion rates are 1/10th of the EPA default drinking water rates. The multiplication
product was divided by the average weight for an adult (70 kg) or for a 10-year-old
child (36 kg). The resulting dose was then multiplied by a factor of 208/365,
because the exposure was assumed to occur four times a week throughout the year.
Sediment Ingestion
Exposure doses for ingestion of contaminants from the sediment were calculated
by use of the maximum concentration measured in the sediment, in mg/kg or ppm,
multiplied by 1/10th of the soil ingestion rate–10 mg/day for adults or
20 mg/day for children. The multiplication product was divided by the average
weight for an adult (70 kg) or a 10-year-old child (36.3 kg). The resulting
dose was then multiplied by a factor of 208/365, because the exposure was assumed
to occur four times a week throughout the year. For the purpose of estimating
future residential exposures, a 1-year-old child (10 kg or 22 pounds) was assumed
to be exposed throughout the year (i.e., the exposure factor was 1).
Noncancer Health Effects
The calculated exposure doses are then compared to an appropriate health guideline
for that chemical. Health guideline values are considered safe doses–that
is, health effects are unlikely below this level. The health guideline value
is based on valid toxicological studies for a chemical, with appropriate safety
factors built in to account for human variation, animal-to-human differences,
and/or the use of the lowest adverse effect level. For noncancer health effects,
the following health guideline values are used.
Minimal Risk Level (MRLs)–Developed by ATSDR
An MRL is an estimate of daily human exposure–by a specified route and
length of time–to a chemical dose 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. A list of MRLs can be found at http://www.atsdr.cdc.gov/mrls.html.
Reference Dose (RfD) - Developed by EPA
An RfD is an estimate, with safety factors built in, of the daily lifetime exposure
of human populations to a possible hazard that is not likely to cause noncancerous
health effects. RfDs can be found at http://www.epa.gov/iris.
If the estimated exposure dose for a chemical is less than the health guideline
value, then the exposure is unlikely to cause a noncarcinogenic health effect
in that specific situation. If the exposure dose for a chemical is greater than
the health guideline, then the exposure dose is compared to known toxicologic
values for that chemical and is discussed in more detail in the PHA. These toxicologic
values are doses derived from human and animal studies that are summarized in
the ATSDR Toxicological Profiles. A direct comparison of site-specific
exposure and doses to study-derived exposures and doses that cause adverse health
effects is the basis for deciding whether health effects are likely.
Calculation of Risk of Carcinogenic Effects
The estimated risk of developing cancer resulting from exposure to the contaminants
was calculated by multiplying the site-specific adult exposure dose by EPA's
corresponding CSF (which can be found at http://www.epa.gov/iris).
The results estimate the maximum increase in the risk of developing cancer after
70 years of exposure to the contaminant. If the duration of possible exposure
to the contaminant is less than 70 years, the estimate is reduced by the appropriate
fraction (for example, for a duration of 10 years, the product of adult exposure
dose and CSF would be multiplied by 10/70).
The actual risk of cancer is probably lower than the calculated number, which
gives a worst-case excess cancer risk. The method used to calculate EPA's CSF
assumes that high-dose animal data can be used to estimate the risk for low-dose
exposures in humans. The method also assumes that no safe level exists for exposure.
Little experimental evidence exists to confirm or refute those two assumptions.
Lastly, the method computes the 95% upper bound for the risk, rather than the
average risk, suggesting that the cancer risk is actually lower, perhaps by
several orders of magnitude.2
Because of uncertainties involved in estimating carcinogenic risk, ATSDR employs
a weight-of-evidence approach in evaluating all relevant data.3 Therefore, the
carcinogenic risk is described in words (qualitatively) rather than giving a
numerical risk estimate only. The numerical risk estimate must be considered
in the context of the variables and assumptions involved in the risk's derivation
and in the broader context of biomedical opinion, host factors, and actual exposure
conditions. The actual parameters of environmental exposures must be given careful
consideration in evaluating the assumptions and variables relating to both toxicity
and exposure.
APPENDIX B: PUBLIC COMMENTS RECEIVED
This public health assessment (PHA) was available for public review and comment
at the Portsmouth Campus Library of Tidewater Community College in Portsmouth,
Virginia and at the offices of the Norfolk Corps of Engineers on Front Street
in Norfolk, Virginia from December 1, 2003 to January 20, 2004. The document
was also available for viewing or downloading from the ATSDR web site.
The public comment period was announced in local newspapers. The public health
assessment was sent to members of the FNOD RAB; private citizens; and staff
in Virginia DEQ, ACE, and EPA. Only one comment on the public health assessment
was received.
Comments
From a member of the FNOD Restoration Advisory Board (RAB):
Has ATSDR evaluated the exposure to a resident if a homeowner had a shallow
well put down to use the water for watering the lawn, or filling a child's wading
pool?... I realize that any residential subdivision home built in that area,
by law, would connnect to the municpal water system. Aside from that, many homeowners
in this area will also put down a shallow well for yard use. Oft times children
(as well as adults) will drink that water. Would this present a hazardous situation
for incidental use of this water? How much would an individual have to consume
in a day, week, month, year, etc. to pose a health threatening condition?
Response: Thank you for the question. In response to your concern, we estimated
exposures to the shallow groundwater from swimming and wading pool activities;
watering the lawn; and occasional ingestion from drinking out of the hose in
the yard. We have already recommended that the groundwater at the site not be
use for drinking water unless it is fully characterized to ensure its safety
(see page 36), so this review is in addition to that recommendation.
We want to point out that making these estimates is full of uncertainties.
The shallow groundwater has been sampled in certain locations (source areas)
across the FNOD site, generally where chemical contamination was present or
suspected. Those areas may not be representative of the whole site. Most likely,
the source areas have higher levels of contaminants, but because of this uncertainty,
we used the maximum concentrations detected in each area. The shallow groundwater
quality will vary across the site, depending on historical use of the land and
the depth of the well. In general, surface activities would be expected to impact
shallow groundwater to a greater extent than deeper groundwater.
Given the uncertainties of what shallow groundwater at a particular property
might contain, we looked at the groundwater data that we do have from the possible
source areas and estimated the exposures to the maximum concentrations found.
We made the following assumptions:
Children and adults would drink 100 milliliters of water (~1/2 cup) every
day for 4 months of the year (this would include accidental swallowing of pool
water and the occasional drink from the garden hose),
Children and adults would have contact with the water from wading or
swimming activities for 2 hours every day for 3 months (dermal exposure), and
Residents would water their vegetable gardens with the groundwater throughout
the growing season.
Based on these assumptions and the chemical concentrations detected, occasional
exposure to the site groundwater from dermal contact and from limited ingestion
are not likely to cause adverse human health effects. The estimated doses are
all below levels where one would expect to see health effects. In addition,
the chemicals in the groundwater are not likely to accumulate in garden produce
so as to harm humans. TNT in the soil and groundwater could be taken up by plants.
However, exposure to TNT at the TNT Burial Site area is unlikely in the future
because a cleanup is underway and residential development in this area will
be restricted [102].
APPENDIX C: ATSDR GLOSSARY OF ENVIRONMENTAL HEALTH 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).
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.
Bioavailability:
See Relative Bioavailability.
Biota:
Used in public health, things that humans would eat B including animals,
fish and plants.
Cancer:
A group of diseases which occur when cells in the body become abnormal and
grow, or multiply, out of control
Cancer Slope Factor (CSF):
The slope of the dose-response curve for cancer. Multiplying the CSF by
the dose gives a prediction of excess cancer risk for a contaminant.
Carcinogen:
Any substance shown to cause tumors or cancer in experimental studies.
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 (CV):
Concentrations 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. This act created
ATSDR and gave it the responsibility to look into health issues related to
hazardous waste sites.
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 results.
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 the 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.
US 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:
Source of Contamination,
Environmental Media and Transport Mechanism,
Point of Exposure,
Route of Exposure, and
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
B 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). Some examples include: the area of a playground
that has contaminated dirt, a contaminated spring used for drinking water,
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:
- 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.
Relative Bioavailability:
The amount of a compound that can be absorbed from a particular medium (such
as soil) compared to the amount absorbed from a reference material (such as
water). Expressed in percentage form.
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
- 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 (see CERCLA) and expanded the health-related
responsibilities of ATSDR. CERCLA and SARA direct ATSDR to look into the health
effects resulting 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.
2 US Environmental Protection Agency (EPA), Office of Emergency and Remedial Response. Risk assessment guidance for Superfund, volume 1, human health evaluation manual. Washington, DC: US Environmental Protection Agency; 1989. 3 Agency for Toxic Substances and Disease Registry
(ATSDR). Cancer policy framework. Atlanta (GA): US Department of Health and Human
Services; 1993.
. Accessed on April 7, 2003.
