Public Health Implications of Exposures to Chemicals in Residential Indoor Air
(FORMER) LONG BRANCH MANUFACTURED GAS PLANT SITE
(a/k/a NEW JERSEY NATURAL GAS COMPANY/LONG BRANCH GAS CONTAMINATION)
LONG BRANCH, MONMOUTH COUNTY, NEW JERSEY
APPENDIX A: VAPOR INTRUSION PATHWAY
The Massachusetts Department of Environmental Protection describes the factors that may
influence the vapor intrusion pathway. These can be found on their web site at
http://www.state.ma.us/dep/ors/files/indair.pdf. In addition to the meteorological factors
discussed in the Discussion section of this document, below is a summary of some of the other factors.
Indoor air sources. Both the USEPA and the MADEP recommend that a determination
of sources of volatile chemicals in the residence be conducted. VOCs are numerous in
household products, and could affect results obtained. The March 1, 2003 sampling
event included taking an inventory of household products that might contain the same
chemicals that were being measured. Later, residents were also asked about personal
activities (for example, smoking) that could affect results.
Location and characteristics of groundwater and soil gas contamination. The
concentration of contaminants of concern in groundwater, as well as the volatility of the
contaminants, affects the concentration of contamination in indoor air. The depth of
groundwater compared to the surface of the soil and the distance between the soil and the building also affect how quickly the contaminants of concern can enter the building.
Air exchange rate. The rate at which indoor air is replaced by outdoor air (usually the number of complete or partial exchanges in an hour). This occurs through:
- infiltration (air leaking in through cracks, joints, crawlspaces, and non-airtight gaps in
- windows, doors, etc.);
- natural ventilation (through open doors and windows); and
- mechanical ventilation (any system that mechanically moves air through a building, such as fans or vents).
Pollution depletion mechanisms. Volatile chemicals in a building may be removed from air by chemical breakdown, or by adsorbing onto surfaces.
Building and grounds features. These are unique to each building, and include the size of
the building; the depth of foundation walls; the presence of a slab, crawlspace or
basement, or the presence of cracks in walls or floors that have direct contact with soil.
Chimneys and flues can draw air in at lower levels and exhaust them out at higher levels.
Buildings with exhaust fans and vents, and/or gas or oil furnaces may preferentially draw
soil gases into the indoor air. Ground cover can also influence the concentrations of
volatile chemicals in indoor air. Impermeable ground covers such as pavements or
sidewalks can cause vapors to collect in those areas.
The USEPA guidance (15) also provides more detail on sampling procedures. The guidance
document can be found on their website at
http://www.epa.gov/correctiveaction/eis/vapor/complete.pdf. The USEPA reviews the impact
of background contaminant levels on sampling. Background can include contaminants
introduced into the indoor environment by consumer products or human activities. The USEPA
recommends that an inventory of household products and a survey of personal activities be
conducted prior to sampling. It also recommends that these background sources either be
removed prior to sampling, or carefully considered when evaluating what contaminants are
entering a building through the vapor intrusion pathway, and what may be introduced through other means.
The USEPA notes that concentrations of compounds found in indoor air are often subject to
temporal and spatial variations, which may complicate estimates of exposure. They recommend
the collection of at least one 24-hour sample, and state that two or more sampling events at each
location are desirable. They also recommend that the house be closed 12 to 24 hours before
measurements begin, and that the use of appliances that cause large pressure differences such as
exhaust fans, clothes dryers and furnaces be avoided during this time. They also recommend not sampling near windows and air supplies.
APPENDIX C: REVIEW OF ETHYLBENZENE, TOLUENE AND XYLENES
Ethylbenzene
None of the ethylbenzene levels measured in Seaview Manor living spaces were
above the screening value for further evaluation (2.16 µg/m3).
Low levels were detected in 5 apartments, ranging from, 0.43 to 1.0 µg/m3,
and in 1 crawlspace at 1.7 µg/m3. The remaining units had non-detectable
levels of ethylbenzene. The ATSDR has established an intermediate MRL for inhalation
exposure to ethylbenzene at 1,000 ppb (4,333 µg/m3). There
is no acute or chronic MRL.
Ethylbenzene is a volatile organic compound with a gasoline-like odor at levels
approximately 1,000 times higher than the highest level measured in Seaview
Manor (1.0 µg/m3, or 0.23 ppb) (12). Studies on human exposure
to ethylbenzene show that inhaled ethylbenzene primarily affects the pulmonary
system, and there can be eye irritation. There may also be some short-term effects
on the blood system.
Ethylbenzene has been classified as a possible human carcinogen, although there is limited human evidence and insufficient animal evidence.
Toluene
The highest level of toluene detected in any of the living quarters was 5.4
µg/m3, or 1.44 ppb. This is more than 75 times less than the
reference concentration of 420 µg/m3. The ATSDR has established
acute and chronic Minimal Risk Levels for toluene exposure through inhalation
at 1,000 ppb and 80 ppb, respectively (11). Therefore, the levels found in the
living quarters at Seaview Manor are unlikely to result in adverse health effects.
Toluene is a common outdoor air contaminant because gasoline contains 5 to 7% toluene. The
ATSDR estimates that levels between 1.3 and 6.6 ppb are typical in suburban and urban areas.
Toluene is also a common indoor air contaminant because it is found in many household
products, including paints, paint thinners, adhesives, and nail polish, as well as in cigarette
smoke (11). In fact, indoor air levels are generally higher than outdoor levels.
At levels significantly higher than those found in Seaview Manor, toluene can effect the nervous
system. Workers exposed to an average of 32,000 ppb for an average of 16 years showed an
alteration in the ability to differentiate colors. This is the basis to establish a Lowest Observed
Adverse Effect Level, or LOAEL. Higher levels showed more serious neurological effects.
Toluene may also be toxic to a developing fetus, according to studies of mothers who abused
toluene while pregnant. Cancer does not appear to be a concern for persons who may experience
low exposures to toluene by living or working near hazardous waste sites containing toluene (11).
Xylenes
There are three forms of xylene, which were measured as a group (total xylenes, referred to as
"xylene" for the remainder of this section).
The highest level of xylene detected in any of the living quarters of Seaview
Manor was 2.8 µg/m3, or 0.65 ppb. This may be compared to the
ATSDR MRLs of 1,000 ppb, 700 ppb, and 100 ppb for acute, intermediate and chronic
exposures, respectively. Therefore, at the levels measured, xylene is not expected
to result in any adverse health effects. Xylene has not been classified for
its ability to cause cancer (13).
Xylenes are widely found in the environment. The individual forms or the mixture of xylenes
are used as solvents, cleaning agents, in paint thinners, and in varnishes. Small amounts are
found in gasoline. It is also a component of cigarette smoke.
A study of workers exposed to xylenes at significantly higher levels than those found in Seaview
Manor living spaces (approximately 7,000 times higher than the highest level measured) found
an increased prevalence of anxiety, forgetfulness, inability to concentrate, and dizziness (13).
APPENDIX D: RESPONSE TO PUBLIC COMMENTS
Commenter A
There is no confirmed impact from the site on the concentrations of chemicals measured.
Response: There is neither a confirmed impact nor a clear indication that the site does not
impact indoor air at Seaview Manor. For this reason, the site is considered to pose an
Indeterminate Public Health Hazard for the vapor intrusion pathway that was evaluated in this Public Health Consultation.
For benzene, the concentrations measured were typical of indoor air concentrations,
the concentration patterns do not point to the crawl spaces as a source, and
there are typically multiple sources of benzene in residences. In the four
units at Seaview Manor in which benzene slightly exceed the NJDEP Reference
Concentration, the indoor benzene concentrations are higher than their respective
crawl space concentrations, suggesting a source other than soil gases. Measured
indoor benzene concentrations in living spaces at Seaview Manor are comparable
to concentrations that people experience from benzene exposure during common
daily activities, and are in the range of normal indoor air concentrations
published by NJDHSS, ATSDR, EPA, and others. When the indoor air concentrations
of benzene are compared to background concentrations, all concentrations measured
indoors are less than the benzene background concentration of up to 6 µ/m3
established by the NJDHSS and ATSDR in the assessment.
Response: The NJDHSS and ATSDR agree and have stated that the benzene levels measured in
indoor air are within the typical background range found in urban environments. Furthermore,
NJDHSS and ATSDR do not identify potential sources of the chemicals measured, but evaluate
the impact those chemicals may have on health at the levels measured.
There is no clear basis for NJDHSS's and ATSDR's assumption that the sampling conditions
in March 2003 did not represent a "worst case scenario." Although standing water, if present,
could have hindered the diffusion of chemicals from soil into crawl space air, NJDHSS/ATSDR
note three factors that would have favored transfer of contaminants from a lower space, such as a
crawl space, up through a building in winter: (1) heated air rising through the building; (2)
migration of frozen soil gases toward warmer, thawed areas of the building foundation and into
the building; and (3) the removal of standing water in at least one building crawl space prior to
sampling. In addition, NJDHSS and ATSDR assume that the concentrations in the units would
be higher in summer. However, because windows would be open in the summer (the buildings
are not air-conditioned), lower indoor air concentrations could occur in summer.
Response: The NJDHSS and ATSDR do not assume that concentrations would be higher in the
summer than winter. We are uncertain if the conditions at the time of monitoring represent the
"worst case scenario," and have stated in the document that "…the results may not represent a
'worst case scenario.' " The USEPA, in its vapor intrusion guidelines, recommend that at least
two rounds of sampling be conducted to verify results over time. Additionally, the NJDEP
recommends two rounds of indoor air sampling, with seasonal monitoring for indoor air
preferred.
Benzene concentrations in the crawl space air are in the range of normal outdoor air
concentrations measured in other parts of the state.
Response: While this is true, the NJDHSS and ATSDR only evaluated air concentrations in
living areas.
NJDHSS and ATSDR should emphasize the health protective nature of the NJDEP
Reference Concentrations for indoor air. In the case of benzene, no adverse health effects were
observed in workers exposed for years to benzene concentrations more than 1,000 times greater
than the NJDEP Reference Concentration.
Response: The NJDEP Reference Concentration is based upon sampling technology, and is not
a health-based standard. The Reference Concentration, as well as the ATSDR Intermediate
MRL for non-cancer outcomes, do consider populations other than workers, and use margins of
safety in developing these values. However, this is noted and added to the section Benzene,
Effects of benzene.
NJDHSS and ATSDR should emphasize that the risk assessment (health consultation)
showed low risk.
Response: This was previously noted in the Summary ("Based on the sample results, the
NJDHSS and ATSDR do not believe that adverse health effects are likely."), as well as the
Conclusion, Public Health Hazard Category ("…the levels detected at that time are not likely to
result in adverse health effects…").
Both the (Citizen's Guide) and the report should be revised to indicate that there is no
confirmed impact from the site on the concentrations of chemicals measured indoors in Seaview
Manor. There is no evidence that contaminants found at Seaview Manor originated from the
Long Branch Manufactured Gas Plant site, as opposed to other sources.
Response: The NJDHSS and ATSDR do not positively identify a source of contamination, as
that is a function of state and federal environmental agencies. However, since the contaminants
of concern (BTEX) were identified and analyzed in and near Seaview Manor as early as 1994
(Table 1), and based on the past practices at the site and the presence of contamination in on-site
soil and groundwater, it is realistic to assume that the site may be at least partially contributing to
the indoor air levels found. Additional testing of air in Seaview Manor, particularly since there
are no longer residents living in the buildings, may provide more definitive information on the source of benzene.
The fact that background risk exceeds 10-6 should be discussed and explained. It should be
emphasized that the low increased risk for cancer associated with the benzene concentrations in
four of the units would be the same as (and perhaps less than) that for background exposure.
Response: In the Cancer Effects discussion under Benzene, the risk is stated to be a "low
increased risk for cancer." However, a statement regarding the cancer risk from exposure to
background levels of benzene is added to the section Benzene, Cancer effects.
NJDHSS and ATSDR should discuss how odor is not necessarily indicative of adverse health
effects (e.g. xylene), and that nausea, which sometimes occurs due to strong odors, is a short term effect that subsides once exposure ceases.
Response: For the purpose of this Public Health Consultation, odors are addressed primarily as
they may relate to BTEX compounds. The consultation states that odors are not likely to occur
at the levels of BTEX measured. Other sources will be discussed further in the full Public
Health Assessment.
NJDHSS and ATSDR note that while particulates can trigger asthma attacks in
individuals with hyperresponsive airways or preexisting airway inflammation,
dusts have been controlled to a level of 0.071 mg/m3 PM10
during remediation under a rigorous protocol approved by the NJDEP. The site-wide
average concentration during remediation from December 2000 to August 2003
(based on samples collected every five minutes) is 0.0085 mg/m3
(8.5 µ/m3), which is well below EPA's National Ambient Air
Quality Standard (NAAQS) for PM10 of 50 ug/m3 as an
annual average.
Response: A discussion on asthma is included in this Public Health Consultation because it is an
issue of concern to community members. Part of the scope of this consultation was to discuss
concerns as they relate to chemicals that may be present through the vapor intrusion pathway.
The discussion on asthma does review other triggers of asthma, including particulates. The data
provided will be evaluated as part of the full Public Health Assessment for the site.
The report should be reorganized so that the toxicity information is presented in the same
place for all compounds (i.e., BTEX is all together instead of benzene in the body of the report and toluene, ethylbenzene and xylenes in an appendix.
Response: Generally, only contaminants measured at levels above comparison values are
evaluated in a Public Health Consultation. Toluene, ethylbenzene, and xylenes are at levels
below comparison values, but are included as an education component as requested by
community members. They are listed in an appendix instead of the body because of their
importance relative to benzene.
The authors should specifically point out that the health effects associated with high
concentrations of benzene are not relevant to any exposures at Seaview Manor where high
concentrations of benzene in air were not measured.
Response: The section Effects of Benzene is amended to include information on one of the
"high levels of exposure" and disease outcome as a comparison.
The use of multiple comparison values for benzene is confusing. All of the numbers should
be discussed and presented in one place, where discrepancies should be discussed and clarified.
Response: The ATSDR MRLs and the NJDEP Reference Concentrations are presented in
tabular form, under "Discussion." Although MRLs were defined, the NJDEP Reference
Concentration was not. The table has been amended to incorporate the derivation of the NJDEP
RC. Since only benzene has a Cancer Risk Evaluation Guideline (CREG) discussion of this
comparison value is only incorporated into the text reviewing cancer the effects of benzene.
Commenter B
The report is written so that our community can read and understand its essence. The glossary and other explanatory comments were very helpful.
The report addresses issues of our community concerns, (including) respiratory, cancer,
(and) stress, but we are not aware of other possible health impacts such as brain, skin or eye
diseases.
Response: The NJDHSS and ATSDR thank you for your comments.
The report should state in bold faced letters in the Summary and various tables and where
appropriate, that "This report is an analysis of data collected and provided by NJNG consultants,
only."
Response: The source of data sets are included in the text.
The classification "Indeterminate Public Health Hazard" in the Summary should be followed
by the recommendation for further testing under the various conditions that the residents
experienced.
Response: The summary is amended to include recommendations.
The classification "No Apparent Public Health Hazard" for the two day care centers should
be reconsidered with future testing, since the day care centers relocated the children on at least
two occasions during remediation, and nearby borings indicate the presence of contaminants in
the surrounding soil, to place community readers at ease with the report.
Response: The "No Apparent Public Health Hazard" category for the day care centers is based
solely on the sampling conducted on March 27-28 and April 9-10, 2003. All pathways of
exposure relating to the day care centers will be incorporated into the full Public Health
Assessment.
The "Actions Planned" seem to be all-inclusive, and when completed would provide our
community with some confidence in the impact of the situations/exposures, whether hazardous
or not.
Response: The NJDHSS and ATSDR thank you for your comments.
The future testing should be mandatory, and it would be helpful if NJDHSS and ATSDR did
some limited testing for verification/certification.
Response: The NJDHSS and the ATSDR do not have the regulatory authority to make
additional testing mandatory.
Commenter C
Dust suppression, odor control and air monitoring: The last paragraph of the Summary
Section (pages 4 and 5) and Recommendation 3 (page 18) may be misinterpreted as written. The
report could be interpreted to suggest that the NJDHSS is recommending that measures be taken
to prevent exposures to dusts and odors during soil remediation because such measures have not
been taken in the past, even though such measures are a standard NJDEP requirement during soil
remedial actions. The commenter recommends that the Summary section and Recommendation
3 be revised to clearly relay that dust suppression and odor control measures were in place
throughout the soil remedial action conducted and that the NJDEP will continue to require such
measures for all future soil remedial actions. These portions of the report should further clarify
that real-time air monitoring has been, and will continue to be conducted as required by the
NJDEP as a method for documenting the effectiveness of these measures in reducing/preventing
exposure to dusts and odors potentially associated with soil remediation.
Public Health Implications: Benzene - Cancer Effects: This section of the report (page 13)
explains how the NJDHSS calculates risk based on the highest benzene levels detected. The
commenter recognizes that this is standard practice, but recommends that the NJDHSS revise the
report to indicate that the highest benzene levels detected in this study are below typical ambient
levels recorded for urban areas. Such a revision would provide an added perspective to the
benzene levels detected.
Response: The first three sentences of the Benzene section list ambient, or background, levels of
benzene, and the levels found at Seaview Manor. However, in response to Commenter A,
comment number 8, the cancer risk related to background levels of benzene has been
incorporated in to the document.
Conclusions: Public Health Hazard Category: The Report (page 18) concludes that the
indoor air exposures among residents of the Seaview Manor Property represent an
"Indeterminate Public Health Hazard." This conclusion is largely because it does not consider
the flooding conditions that existed when the March 1, 2003 sampling was conducted as typical
for the area. The commenter recommends that the NJDHSS contact the Long Branch Housing
Authority (LBHA) to verify the accuracy of utilizing this information as the basis for this
determination prior to finalizing the Report. According to statements made by a LBHA
representative to an NJDEP representative during the March 1, 2003 sampling event, flooding in
Building B is a typical condition for that time of year. If the NJDHSS confirms that the flooding
conditions are in fact typical for the area during that time of year, then the NJDHSS may wish to
re-evaluate its determination.
Response: Please see response to the following comment.
Recommendations - Recommendation 1 (page 18) states that the NJDHSS and the ATSDR
recommend that additional indoor air sampling be conducted in residential living spaces at
Seaview Manor. The NJDHSS is advised that the NJDEP currently recommends a minimum of
two rounds of indoor air sampling, with seasonal monitoring for indoor air preferred. The
Department also recommends that future use of Seaview Manor be considered with respect to
implementing this recommendation.
Response: Although the future use of Seaview Manor as it presently exists may not occur, the
NJDHSS and ATSDR consider past exposures in identifying health risks. Therefore, additional
sampling to reflect a broader range of exposures would provide a better basis for a hazard
category conclusion.
Actions taken: With regard to number 6 (page 19), the Report states that "as is NJDEP
policy, the New Jersey Natural Gas Company has real-time monitoring in place to reduce odors
and dust emissions during site remediation." As a point of clarification, real-time air monitoring
is conducted to verify the efficiency of the dust suppression and odor control methods.
However, the monitoring itself does not reduce odors or dust emissions.
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 (t˝) :
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
. In addition to the meteorological factors
discussed in the Discussion section of this document, below is a summary of some of the other factors.
