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PUBLIC HEALTH ASSESSMENT

ST. JULIENS CREEK ANNEX (U.S. NAVY)
CHESAPEAKE, CHESAPEAKE COUNTY, VIRGINIA


APPENDICES

APPENDIX A: 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:
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 sampling:
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 sampling.


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 level 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).


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 level of a chemical that can reliably be distinguished from a zero level.


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.


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 follow-up 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 level 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].


Level:
The amount of a substance present in a certain amount of soil, water, air, food, blood, hair, urine, breath, or any other media.


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 sampling:
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 level 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 Site 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.


Other glossaries and dictionaries:
Environmental Protection Agency (http://www.epa.gov/OCEPAterms/ Exiting ATSDR Website)

National Center for Environmental Health (CDC)
(http://www.cdc.gov/exposurereport/ Exiting ATSDR Website)

National Library of Medicine (NIH)
(http://www.nlm.nih.gov/medlineplus/mplusdictionary.html Exiting ATSDR Website)


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: COMPARISON VALUES

ATSDR health assessors use comparison values (CVs) as screening tools to evaluate environmental data that are relevant to the exposure pathways. CVs represent media-specific contaminant levels that are much lower than exposure levels observed to cause adverse health effects. In that way, CVs are protective of public health in essentially all exposure situations. If the levels 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 levels below the CV are not expected to lead to any observable health effect, it should not be inferred that a level 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. Rather, they are used by ATSDR to select contaminants for further evaluation to determine the possibility of adverse health effects.

CVs used in this PHA include:

Cancer Risk Evaluation Guide (CREG):
Estimated contaminant levels 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 slope factors (CSFs).


Environmental Media Evaluation Guide (EMEG):
EMEGs are based on ATSDR minimal risk levels (MRLs) and factor in body weight and ingestion rates. An EMEG is an estimate of daily human exposure to a chemical (in mg/kg/day) that is likely to be without noncarcinogenic health effects over a specified duration of exposure to include acute, intermediate, and chronic exposures.


Reference Media Evaluation Guides (RMEG):
ATSDR derives RMEGs from EPA's oral reference doses (RfDs). The RMEG represents the level in water or soil at which daily human exposure is unlikely to result in adverse noncarcinogenic effects.


EPA's Region III Risk-Based Level (RBC):
The U.S. Environmental Protection Agency (EPA) combines RfDs and CSF with "standard" exposure scenarios to calculate risk-based levels (RBCs), which are chemical levels 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 level) in water, air, fish tissue, and soil.


EPA Maximum Contaminant Level (MCL):
The MCL is the drinking water standard established by the 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.

CVs are derived from available health guidelines, such as ATSDR's MRLs and EPA's RfDs, and EPA's CSFs. These guidelines are based on the no-observed adverse effect levels (NOAEL), lowest-observed adverse effect levels (LOAELs), or the cancer effect levels (CELs) reported for a contaminant in the toxicologic literature. A description of these terms is provided:

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.


Reference Dose (RfD):
The RfD is an estimate, with safety factors 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.


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.


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 or following human exposure.


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


Cancer Effect Level (CEL):
The CEL is the lowest dose of a chemical in a study, or group of studies, that was found to produce increased incidences of cancer (or tumors).

APPENDIX C: ATSDR'S HEALTH EFFECTS EVALUATION

Estimates of Human Exposure Doses and Determination of Health Effects

Introduction

The health hazards that could plausibly result from exposures to contaminants detected at St. Juliens Creek Annex and nearby areas are discussed in further detail in this appendix. It is important to note that public health hazards from environmental contamination happen only when (a) people are exposed to the contaminated media and (b) the exposure is at high enough doses to result in an effect.

As an initial screen, ATSDR evaluated available data to determine whether contaminants were accessible to the public or were above ATSDR's comparison values. The majority of detected contaminants were either not accessible to the public or fell at or below comparison values and were not evaluated further. Exposure situations with contaminants above comparison values or that had insufficient environmental data were deemed worthy of further evaluation. These exposure situations are:

Deriving Exposures Doses

After identifying contaminants in site media above comparison values and identifying potential pathways of exposure, ATSDR further evaluates exposures to detected contaminants considering information about exposures combined with scientific information from the toxicologic and epidemiologic literature. If necessary, ATSDR estimates exposure doses, which are estimates of how much contaminant a person is exposed to on a daily basis. Variables considered when estimating exposure doses include the contaminant level in the environmental media, the exposure amount (how much of the substance the person was actually exposed to), the exposure frequency (how often), and the exposure duration (how long).

Evaluating Potential Health Hazards

The estimated exposure doses can be used to evaluate potential noncancer and cancer effects associated with contaminants detected in site media. When evaluating noncancer effects, ATSDR compares the estimated exposure dose to standard toxicity values, including ATSDR's minimal risk levels (MRLs) and the U.S. Environmental Protection Agency's reference doses (RfDs), to evaluate whether adverse effects may occur. The chronic MRLs and RfDs are estimates of daily human exposure to a substance that is likely to be without appreciable risk of adverse noncancer effects over a specified duration. The chronic MRLs and RfDs are conservative values, based on the levels of exposure reported in the literature that represent no-observed-adverse-effect levels (NOAEL) or lowest-observed-adverse-effect-levels (LOAEL) for the most sensitive outcome for a given route of exposure (e.g., dermal contact, ingestion). Uncertainty (safety) factors are applied to NOAELs or LOAELs to account for variation in the human population and uncertainty involved in extrapolating human health effects from animal studies. ATSDR also reviews the toxicologic literature and epidemiology studies to further evaluate the weight of evidence for adverse effects.

ATSDR also evaluates the likelihood that site-related contaminants will cause cancer in people who would not otherwise develop it. As an initial screen, ATSDR calculates a theoretical increase of cancer cases in a population over a lifetime of exposure using EPA's cancer slope factors (CSFs), which represent the relative potency of carcinogens. This is accomplished by multiplying the calculated exposure dose by a chemical-specific CSF. CSFs are developed using data from studies of animals or humans exposed to known doses of a particular chemical. Because CSFs are derived using mathematical models which apply a number of uncertainties and conservative assumptions, risk estimates generated by using CSFs tend to be overestimated. Although no risk of cancer is considered acceptable, it is impossible to achieve a zero cancer risk. Consequently, ATSDR often uses a range of 10-4 to 10-6 estimated lifetime cancer risk (1 new case in 10,000 to 1,000,000 exposed persons), based on conservative assumptions about exposure, to determine the likelihood of excess cancer resulting from this exposure.

ATSDR also compared an estimated lifetime exposure dose to available cancer effect levels (CELs). An estimated lifetime exposure dose is defined as a dose that produces significant increases in the incidence of cancer or tumors. The CEL is the lowest dose of a chemical in a study, or group of studies, that was found to produce increased incidences of cancer (or tumors). In addition, genotoxicity studies are also reviewed to understand further the extent to which a chemical might be associated with cancer outcomes. This process enables ATSDR to weigh the available evidence in light of uncertainties and offer perspective on the plausibility of harmful health outcomes under site-specific conditions.

Using other methods to evaluate potential health hazards

When dealing with exposure to lead, ATSDR uses an additional approach to the traditional methodologies described above. A substantial part of human health effects data for lead are expressed in terms of blood lead level rather than exposure dose. The Centers for Disease Control and Prevention (CDC) has determined that health effects are more likely to be observed if blood lead levels are at or above 10 µg/dL. ATSDR developed an approach that uses media-specific uptake parameters to estimate what cumulative blood lead level might result from exposure to a given level of contamination. However, historical blood lead data were available for St. Juliens Creek Annex. Blood lead data are expected to provide a more accurate indicator of possible health effects associated with lead. Therefore, this public health assessment does not evaluate the blood lead levels that could result from the lead levels found.

Essential nutrients and naturally occurring elements (e.g., calcium, magnesium, potassium, and sodium) were also detected in soil, surface water, and sediment samples. These substances are important minerals that maintain basic life functions; therefore, their presence in the sediment is not of health concern. They are found in many foods, such as milk, bananas, and table salt. Ingestion of these essential nutrients at the levels detected found at this site will not result in harmful health effects.

Estimated Exposure Doses for Incidental Ingestion of On-Site Soil

Volatile organic compounds, pesticides, and metals and other inorganic elements were detected in on-site soil at landfills and other industrial areas at St. Juliens Creek Annex, at levels above ATSDR CVs for soil. The primary exposure pathway of concern is through incidental ingestion of soil for individuals, primarily teenagers or young adults exploring industrial areas of St. Juliens Creek Annex. ATSDR assumed that young children would not have access to the industrial areas because most are far away from the housing areas and unlikely to be visited by unsupervised children.

ATSDR estimated exposure doses to contaminants in the soil. Because site-specific information about exposure was not available, ATSDR used protective assumptions when deriving the doses. ATSDR assumed that an adult might incidentally ingest 100 mg/day of soil (EPA 1997), which is the default rate generally used when evaluating adult soil exposure. This is a conservative or protective assumption because people are not likely to contact this amount of soil from the same location on a daily basis. Protective assumptions enable ATSDR to evaluate the likelihood, if any, that detected levels of contaminants could cause harm to recreational users.

ATSDR derived exposure doses for antimony, arsenic, barium, cadmium, chromium, copper, manganese, nickel, vanadium, 4,4'-DDT, 4,4'-DDE, Aroclor-1254, Aroclor-1260, dieldrin, polycyclic aromatic hydrocarbons (PAHs), BTEX (benzene, toluene, ethylbenzene, and xylene), and chloromethane (methyl chloride), and detected in on-site soil. Tables C-1 and C-2 present the estimated noncancer and cancer exposure doses, respectively, to these contaminants in the soil at on-site locations. ATSDR used the following equation and assumptions to estimate the exposure dose for ingestion of on-site soil:

Estimated Exposure Dose equals Conc. times IR times CF times EF times ED divided by BW times AT

where:

Conc.: Maximum contaminant level in soil (mg/kg or ppm)
IR: Ingestion rate: 100 mg/day for an adult (EPA 1997)
CF: Conversion factor of 10-6
EF: Exposure frequency (exposure events per year of exposure): 2 days/week
ED: Exposure duration or the duration over which exposure occurs: adult=30 yrs
BW: Body weight: adult=70 kg (154 pounds)
AT: Averaging time or the period over which cumulative exposures are averaged (6 years x 365 days/year for noncancer effects or 70 years for cancer)

Noncancer Effects

ATSDR compared the estimated dose for each contaminant to its respective MRL or RfD. The estimated doses to an adult for all contaminants in on-site soil were below the corresponding MRL or RfD. Considering the conservative nature of our estimates, exposures to the contaminants in on-site soil is unlikely to be of public health concern.

Children likely did not have access to on-site soil, but they lived in on-site housing areas where they were likely exposed to higher levels of lead in soil and dust in their immediate environment. The estimated contribution to blood lead levels for a child living in the on-site housing areas is discussed in the "Community Health Concerns" portion of this PHA.

Cancer Effects

EPA has classified arsenic, 4,4'-DDT, 4,4'-DDE, Aroclor-1254, Aroclor-1260, dieldrin, and PAHs, as human or probable human carcinogens via the oral route of exposure. ATSDR estimated theoretical cancer risk from contacting each of these contaminants at the detected level. All cancer risk levels (10-5 to 10-7) are safely below the range considered to pose excess cancer risk. ATSDR also compared the estimated cancer dose for a contaminant to the lowest CEL reported in the toxicologic literature to further assess the potential for cancer effects to occur. The estimated doses ranged from 40 to 330,000,000 times lower than the levels at which cancer has been observed in human or animal studies. ATSDR therefore concludes that people who incidentally ingest soil during activities at the on-site industrial or Waste Disposal Area Areas are not at increased likelihood of developing cancer.

Estimated Exposure Doses for Incidental Ingestion of On-Site and Off-Site Sediment

Semivolatile organic compounds, dioxins, pesticides, and metals and other inorganic elements were detected in sediment at the Blows Creek located at St. Juliens at levels above ATSDR CVs for soil. Elevated levels of these contaminants were also detected in sediment at off-site locations along St. Juliens Creek and the Elizabeth River, at levels above ATSDR CVs for soil. They were also detected on-site in shallow marsh areas near site landfills, although ATSDR expects that individuals would have accessed these areas less frequently. Adults and children living in on-site housing could have come in contact with contaminants in sediment while wading along Blows Creek in the past or from incidental ingestion during wading and other recreational activities at the St. Juliens Creek and the Elizabeth River. The primary exposure pathway of concern is incidental ingestion of contaminants. Most of the contaminants are not readily absorbed through the skin, therefore, posing minimal, if any, health risk from dermal contact.

ATSDR evaluated the health effects that could possibly result from incidental ingestion of sediment containing aluminum, aldrin, antimony, arsenic, dieldrin, or PAHs. In estimating the exposure doses, ATSDR assumed that an adult might incidentally ingest 100 mg/day of sediment and that a child might ingest 200 mg/day of sediment (EPA 1997). These intake rates are the default rates generally used when evaluating soil/sediment exposures. As such, it is likely a conservative assumption because people are not likely to contact this amount of sediment from the same location on a daily basis.

Tables C-3 and C-4 summarize the estimated exposure doses to contaminants in the sediment at on-site and off-site locations. The following presents the equation and assumptions used to estimate the exposure dose:

Estimated Exposure Dose equals Conc. times IR times CF times EF times ED divided by BW times AT

where:

Conc.: Maximum contaminant level in sediment (mg/kg or ppm)
IR: Ingestion rate: 100 mg/day for an adult and 200 mg/day for a child (EPA 1997)
CF: Conversion factor of 10-6
EF: Exposure frequency (exposure events per year of exposure): 2 days/week
ED: Exposure duration or the duration over which exposure occurs: adult=30 yrs; child=6 yrs
BW: Body weight: adult=70 kg (154 pounds); child=16 kg (34 pounds)
AT: Averaging time or the period over which cumulative exposures are averaged (6 or 30 years x 365 days/year for noncancer effects or 70 years for cancer)

Noncancer Effects

ATSDR compared the estimated dose for each contaminant to its respective MRL or RfD. The estimated dose to a child or an adult, for contaminants in on-site and off-site sediment, never exceeded the corresponding MRL or RfD. Based on these findings, ATSDR does not expect that individuals who incidentally ingested sediment while visiting these waterways will develop adverse noncancer health effects.

Lead was detected in sediment. However, as discussed earlier in this appendix, ATSDR did not evaluate the blood lead levels that could result from these detected levels of lead in sediment, because historical blood lead data are available for this site. Additionally, children with access to on-site sediment lived in on-site housing areas where they were likely exposed to higher levels of lead in soil and dust in their immediate environment. The estimated contribution to blood lead levels for a child living in the on-site housing areas is discussed in the "Community Health Concerns" portion of this PHA. Exposure to lead in sediment is not likely to result in adverse health effects.

Cancer Effects

EPA has classified aldrin, arsenic, dieldrin, and PAHs as human or probable human carcinogens via the oral route of exposure. ATSDR estimated theoretical cancer risk from contacting each of these contaminants at the detected level. All cancer risk levels (10-5 to 10-7) are safely below the range considered to pose excess cancer risk. ATSDR also compared the estimated cancer dose for a contaminant to the lowest CEL reported in the toxicologic literature to further assess the potential for cancer effects to occur. The estimated doses were more than 190 to 35,000,000 times lower than the levels at which cancer has been observed in human or animal studies. ATSDR therefore concludes that people who incidentally ingest sediment during activities at the on-site or nearby water bodies are not at increased likelihood of developing cancer.

Estimated Exposure Doses for Incidental Ingestion of On-Site Surface Water

Semivolatile organic compounds, pesticides, and metals were detected in surface water in Blows Creek located on site and at marsh areas near the on-site landfills at levels above ATSDR CVs. Children living in on-site housing could have come in contact with contaminants in surface water at Blows Creek in the past. Adults and older children also could have contacted contaminants in the marsh areas near the on-site landfills. The primary exposure pathway of concern is through incidental exposure of water while visiting or using the water for recreation. ATSDR evaluated the health effects that could possibly result from incidental ingestion of surface water containing these constituents. Most of the contaminants are not readily absorbed through the skin, therefore, posing minimal, if any, health risk from dermal contact.

ATSDR estimated doses for aluminum, antimony, arsenic, beryllium, cadmium, chromium, cobalt, copper, manganese, nickel, thallium, vanadium, and zinc. In deriving the exposure doses, ATSDR assumed that people ingested about 0.15 liters (about 1/2 to 3/4 cup) of surface water while swimming (EPA 1997). ATSDR assumed that people were directly exposed to the surface water twice a week, all year long. ATSDR also assumed that an adult could have been exposed to the detected contaminant levels collected in more recent years for a period of 30 years, and a child for 6 years. These are highly conservative assumptions because people are not likely to visit the surface water all year, swim frequently in these areas, or consistently ingest that much surface water while swimming.

Tables C-5 and C-6 summarize the estimated exposure doses to contaminants in the surface water. The following presents the equation and assumptions used to estimate the exposure dose:

Estimated Exposure Dose equals Conc. times IR times CF times EF times ED divided by BW times AT

where:

Conc.: Maximum contaminant level in sediment (mg/kg or ppm)
CF: Conversion factor of 10-6
IR: Ingestion rate: 100 mg/day for an adult and 200 mg/day for a child (EPA 1997)
EF: Exposure frequency (exposure events per year of exposure): 2 days/week
ED: Exposure duration or the duration over which exposure occurs: adult=30 yrs; child=6 yrs
BW: Body weight: adult=70 kg (154 pounds); child=16 kg (34 pounds)
AT: Averaging time or the period over which cumulative exposures are averaged (6 or 30 years x 365 days/year for noncancer effects or 70 years for cancer)

Noncancer Effects

ATSDR compared the estimated doses to the respective MRL or RfD. In all cases, the estimated dose to an adult and child for a contaminant was similar to (i.e., mercury) or below its corresponding MRL or RfD. Therefore, even assuming daily exposure to the maximum detected level of these contaminants, exposures are unlikely to be of public health concern.

Lead was also detected in surface water. However, as discussed earlier in this appendix, ATSDR did not evaluate the blood lead levels that could result from these detected levels of lead in surface water, because historical blood lead data are available for this site. Additionally, children with access to on-site surface water lived in on-site housing areas where they were likely exposed to higher levels of lead in soil and dust in their immediate environment. The estimated contribution to blood lead levels for a child living in the on-site housing areas is discussed in the "Community Health Concerns" portion of this PHA. ATSDR does not expect that exposure to lead in surface water posed a health hazard to a child playing in that area.

Cancer Effects

EPA has classified arsenic as a human carcinogen via the oral route of exposure. ATSDR estimated theoretical cancer risk from accidentally ingesting water during swimming with detected levels of arsenic. The cancer risk level (10-5) is safely below the range considered to pose increased cancer risk. ATSDR also compared the estimated cancer dose for a contaminant to the lowest CEL reported in the toxicologic literature to further assess the potential for cancer effects to occur. The estimated dose is about 64 times lower than the lowest level at which cancer has been observed in human studies. With this information, ATSDR concludes that people who incidentally ingest surface water while swimming or during other recreational activities are not at increased likelihood of developing cancer.

References

Agency for Toxic Substances and Disease Registry (ATSDR). 1996. Toxicological profile for PAHs. Atlanta: US Department of Health and Human Services. September 1996.

ATSDR. 1999. Toxicological profile for lead (update). Atlanta: US Department of Health and Human Services. July 1999.

ATSDR. 2000a. Toxicological profile for arsenic. Atlanta: US Department of Health and Human Services. September 2000.

ATSDR. 2000b. Toxicological profile for polychlorinated biphenyls. Atlanta: US Department of Health and Human Services. November 2000.

ATSDR. 2002a. Toxicological profile for DDT, DDE, and DDD (update). Atlanta: US Department of Health and Human Services. September 2002.

ATSDR. 2002b. Toxicological profile for aldrin/dieldrin. Atlanta: US Department of Health and Human Services. September 2002.

EPA. 1997. Exposure Factors Handbook. 1997 August. http://www.epa.gov/ncea/exposfac.htm Exiting ATSDR Website.

Table C-1. Estimated Exposure Doses--Noncancer Effects, Incidental Ingestion of On-Site Soil
Contaminant On-Site Soil Health Guideline (mg/kg/day) Basis for Health Guideline
Maximum Level (ppm) Estimated Exposure Dose (mg/kg/day)
Antimony 162 0.000066 0.0004 Chronic oral RfD
Arsenic 152 0.000062 0.0003 Chronic oral MRL
Barium 5,970 0.00244 0.07 Chronic oral RfD
Cadmium 396 0.000162 0.0002 Chronic oral MRL
Chromium 1,040 0.000424 0.003 Chronic oral RfD (hexavalent)
Copper 42,500 0.0173 0.02 Acute oral MRL
Manganese 935 0.000382 0.02 NCEA-IRIS value
(non-food value)
Nickel 1,400 0.000571 0.02 Chronic oral RfD
Vanadium 5,330 0.00218 0.003 Int. oral MRL
4,4'-DDT 3.1 0.0000013 0.0005 Int. oral MRL (DDT)
4,4'-DDE 4.7 0.0000019 0.0005 Int. oral MRL (DDT)
Aroclor-1254 9.4 0.0000038 0.00002 Chronic oral MRL
Aroclor-1260 6.3 0.0000026 0.00002 Chronic oral MRL
(Aroclor-1254)
Dieldrin 0.072 2.94 * 10-8 0.00005 Chronic oral MRL
PAHs 22.67 0.0000093 0.00006 Chronic oral RfD
BTEX 5.21 0.0000021 0.3 Int. oral MRL
Chloromethane 0.005 2.04 * 10-9 0.086 NCEA-IRIS value

Key:

mg/kg/day milligrams contaminant per kilogram body weight per day;
MRL ATSDR minimal risk level;
ppb parts per billion;
RfD EPA reference dose.


Table C-2. Estimated Exposure Doses--Cancer Effects, Incidental Ingestion of On-Site Soil
Contaminant On-Site Soil CSF Theoretical Excess Cancer Risk CEL for Orala Exposure (mg/kg/day) Source of CEL
Conc. (ppm) Cancer Dose (mg/kg/day)
Arsenic 152 0.0000266 1.5 4.0 * 10-5 0.0011 Ferreccio et al. 1998
4,4'-DDT 3.1 0.000000542 0.24 1.3 * 10-7 95 Rossi et al. 1983
4,4'-DDE 4.7 0.000000822 0.34 2.8 * 10-7 27 NCI 1978
Aroclor-1254 9.4 0.00000164 2.0 3.3 * 10-6 1 Mayes et al. 1998
Aroclor-1260 6.3 0.0000011 2.0 2.2 * 10-6 1 Mayes et al. 1998
Dieldrin 0.072 0.0000000126 16 2.0 * 10-7 0.33 Walker et al. 1972
PAHs 22.67 0.00000397 7.3 2.9 * 10-5 2.6 Neal and Rigdon 1967

a CELs are reported in ATSDR toxicological profiles (ATSDR 1996, 2000a, 2000b, 2002a, 2002b)
Key:

CEL ATSDR cancer effect level
mg/kg/day milligrams contaminant per kilogram body weight per day;
ppm parts per million


Table C-3. Estimated Exposure Doses--Noncancer Effects, Incidental Ingestion of On-Site and Off-Site Sediment
Contaminant On-Site Sediment Off-Site Sediment Health Guideline (mg/kg/day) Basis for Health Guideline
Maximum Level (ppm) Estimated Exposure Dose (mg/kg/day) Maximum Level (ppm) Estimated Exposure Dose (mg/kg/day)
Adult Child Adult Child
Aldrin 0.1 0.000000041 N/A N/A 0.00003 Chronic oral RfD
Aluminum N/A 112,000 0.0457 0.64 2 Int. oral MRL
Antimony 173 0.0000706 N/A N/A 0.0004 Chronic oral RfD
Arsenic 61.1 0.0000249 0.000349 9.7 0.00000396 0.0000554 0.0003 Chronic oral MRL
Bis(2-chloroethoxy)methane 1 0.00000041 N/A N/A N/A N/A
Dieldrin N/A 0.054 0.000000022 0.0000003 0.00005 Chronic oral MRL
Dioxins 0.000091 3.71 * 10-11 N/A N/A 0.000000001 Chronic oral MRL
PAHs 10.831 0.0000044 0.0000619 6.98 0.00000285 0.0000399 0.00006 Chronic oral RfD

Note: ATSDR assumes that young children were not able to access the industrial facilities of St. Juliens Creek Annex; therefore the estimated exposure doses to children are based only on contaminant levels measured in Blows Creek, not on contaminant levels in Blows Creek as well as in on-site marsh areas.

Key:

mg/kg/day milligrams contaminant per kilogram body weight per day;
MRL ATSDR minimal risk level;
ppb parts per billion;
RfD EPA reference dose.


Table C-4. Estimated Exposure Doses--Cancer Effects, Incidental Ingestion of On-Site and Off-Site Sediment
Contaminant Conc. (ppm) Cancer Dose (mg/kg/day) On-Site Sediment Conc. (ppm) Cancer Dose (mg/kg/day) Off-Site Sediment CSF Cancer Risk Theoretical Excess Exposure (mg/kg/day) CEL for Orala Source of CEL
Arsenic 33.1 0.00000579 9.7 0.0000017 1.5 1.6 * 10-5 (on-site) 2.5 * 10-6 (off-site) 0.0011 Ferreccio et al. 1998
Dieldrin   0.054 0.00000000945 16 1.5 * 10-7 (off-site) 0.33 Walker et al. 1972
PAHs 8.821 0.00000154 6.98 0.00000122 7.3 1.4 * 10-5 (on-site) 8.9 * 10-6 (off-site) 2.6 Neal and Rigdon 1967

a CELs are reported in ATSDR toxicological profiles (ATSDR 1996, 2000a, 2002b)
Key:

CEL cancer effect level
mg/kg/day milligrams contaminant per kilogram body weight per day;
NA not applicable
ppb parts per billion


Table C-5. Estimated Exposure Doses–Noncancer Effects, Incidental Ingestion of On-Site Surface Water
Contaminant On-Site Surface Water Health Guideline (mg/kg/day) Basis for Health Guideline
Maximum Level (ppb) Estimated Exposure Dose (mg/kg/day)
Adult Child*
Aluminum 95,000 0.0582   2 Int. oral MRL
Antimony 5.1 0.0000031 0.0004 Chronic oral RfD
Arsenic 65.8 0.0000403 0.0000249 0.0003 Chronic oral MRL
Beryllium 22.6 0.0000138   0.002 Chronic oral MRL
Cadmium 8.4 0.0000051 0.0002 Chronic oral MRL
Chromium, hex. 162 0.0000992 0.003 Chronic oral RfD
Cobalt 255 0.000156 0.001 Int. oral MRL
Copper 530 0.000324 0.02 Acute oral MRL
Manganese 7,590 0.00465 0.02 EPA-IRIS
Nickel 364 0.000223 0.02 Chronic oral RfD
Thallium 4.1 0.0000025 0.0000176 0.00007 EPA Other
Vanadium 196 0.00012   0.003 Int. oral MRL
Zinc 4,690 0.00287 0.3 Chronic oral MRL

*Note: ATSDR assumes that young children were not able to access the industrial facilities of St. Juliens Creek Annex; therefore the estimated exposure doses to children are based only on contaminant levels measured in Blows Creek, not on contaminant levels in Blows Creek as well as in on-site marsh areas.

Key:

mg/kg/day milligrams contaminant per kilogram body weight per day;
MRL ATSDR minimal risk level;
ppb parts per billion;
RfD EPA reference dose.


Table C-6. Estimated Exposure Doses--Cancer Effects, Incidental Ingestion of On-Site Surface Water
Contaminant On-Site Surface Water CSF Theoretical Excess Cancer Risk CEL for Orala Exposure (mg/kg/day) Source of CEL
Conc. (ppb) Cancer Dose (mg/kg/day)
Arsenic 65.8 0.0000173 1.5 2.59 * 10-5 (on-site) 0.0011 Ferreccio et al. 1998

a CELs are reported in ATSDR toxicological profiles (ATSDR 2000a)
Key:

CEL cancer effect level
mg/kg/day milligrams contaminant per kilogram body weight per day;
NA not applicable
ppb parts per billion


APPENDIX D: RESPONSE TO PUBLIC COMMENTS

ATSDR received several editorial comments on the public comment release of the Public Health Assessment for St. Juliens Creek Annex. Those comments were addressed in this version.

ATSDR also received some specific comments that are addressed below. We did not receive any comments from individual citizens or citizen groups.

Specific Comments

The first two comments refer to the warning signs placed near the wharf area along the Elizabeth River. Those signs state:

"NO UNAUTHORIZED ACCESS
ENVIRONMENTAL MONITORING IN PROGRESS
EXCAVATION AND DUMPING PROHIBITED
FOR ADDITIONAL INFORMATION CONTACT
CNRMA Environmental Manager 757-444-4009, ext. 358
CNRMA Environmental IR Coordinator 757-887-4775" (LANTDIV 2003d)."

The wording actually makes it seem like the restriction is intended to protect the facility from contamination from boaters. Did ATSDR discuss with the Navy the possibility of rewording the signs to make boaters aware of UXO hazards?

ATSDR did speak with Navy representatives about this concern to get a better sense of the history and rationale for the current wording. Navy personal indicate that while the potential for UXO to exist in the sediment can not be ruled out and metal anomalies were detected below the surface of the sediment, no direct evidence of UXO has been identified. The anomalies exist beneath the surface of soft sediment at a depth where they could not be safely removed without dredging. Sediment samples indicate the chemical concentrations are below levels of health concern. Trace amounts of 1,3-dinitrobenzene was detected in some of the sediment samples. This chemical could represent a trinitrotoluene (TNT) production impurity, however it is also used in commercial products and could be present in the sediment from other sources. TNT was not detected in the sediment. Because the Navy has not identified sufficient evidence to confirm that UXO is present in the sediment there are no immediate plans to continue the investigation. Because it is possible that UXO could be present beneath the surface of the sediment the warning signs were placed to discourage public access.

What type of signage does ATSDR typically recommend at sites where UXO may be present?

ATSDR is not a regulatory agency and therefore does not provide specific recommendations that site managers need to follow. ATSDR evaluates each situation to ensure that the method proposed or enacted by the site manager is likely to prevent exposures to the community that would be expected to cause harm. Although the existing signs do not specifically identify that UXO could be present in the sediment near the wharf, individuals who do not enter the site, excavate sediment from the site, or dump objects into the sediment at the site will be protected from exposure to UXO, if it exists at that site.

Three sites (Sites 9, 11, and 21) have groundwater contaminated with trichloroethylene (TCE). The evaluation for each site notes that groundwater is not used as a drinking water supply. It was not clear from the PHA whether ATSDR evaluated the potential for this contaminant to migrate to areas where vapor intrusion to indoor air could be a concern.

The three sites where TCE was measured in the groundwater above ATSDR CVs are all within approximately 600 feet of each other and occupied buildings are located above or near each of these sites. ATSDR did not consider vapor intrusion to be a potential exposure pathway because 1) the sampling data suggests that extremely high concentrations of TCE in the groundwater is likely present in only specific locations; other groundwater samples in that area had concentrations that ranged from 29 to approximately 2400 ppb, and samples from this location at other times reported a TCE concentration of 18 ppb; 2) EPA (2003) guidance for soil vapor intrusion indicates the indoor air concentration would likely be 100 to 10,000,000 times less than the groundwater concentration depending upon the chemical and other geological and building characteristics; and 3) the ATSDR CV for TCE in air is 100 ppb. Given the spatial and temporal variability of the TCE groundwater concentrations, it is likely that the TCE concentration in the indoor air would be close to 1000 time less than the maximum groundwater concentration. However even if the indoor air concentration was only 100 times less than the maximum groundwater concentration, the estimated indoor air concentration would be in the range of 52 ppb or less; well under the indoor air CV for TCE.

References:
EPA 2003. U.S. EPA Seminar on Indoor Air Vapor Intrusion. February 25-26, 2003. Atlanta, GA

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