PUBLIC HEALTH ASSESSMENT
ST. JULIENS CREEK ANNEX (U.S. NAVY)
CHESAPEAKE, CHESAPEAKE COUNTY, VIRGINIA
EPA FACILITY ID: VA5170000181
The Agency for Toxic Substances and Disease Registry (ATSDR) is a federal publichealth agency with headquarters in Atlanta, Georgia, and 10 regional offices in theUnited States. ATSDR's mission is to serve the public by using the best science,taking responsive public health actions, and providing trusted health information toprevent harmful exposures and diseases related to toxic substances. ATSDR is not aregulatory agency, unlike the U.S. Environmental Protection Agency (EPA), whichis the federal agency that develops and enforces environmental laws to protect theenvironment and human health.
This glossary defines words used by ATSDR in communications with the public. Itis not a complete dictionary of environmental health terms. If you have questions orcomments, call ATSDR's toll-free telephone number, 1-888-42-ATSDR (1-888-422-8737).
- The process of taking in. For a person or an animal, absorption is the process of asubstance getting into the body through the eyes, skin, stomach, intestines, or lungs.
- 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 responsesof all the individual substances added together [compare with antagonistic effect andsynergistic effect].
- Adverse health effect:
- A change in body function or cell structure that might lead to disease or healthproblems
- Requiring oxygen [compare with anaerobic].
- Surrounding (for example, ambient air).
- Requiring the absence of oxygen [compare with aerobic].
- 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, thelaboratory test will determine the amount of mercury in the sample.
- Analytic epidemiologic study:
- A study that evaluates the association between exposure to hazardous substances anddisease by testing scientific hypotheses.
- Antagonistic effect:
- A biologic response to exposure to multiple substances that is less than would beexpected if the known effects of the individual substances were added together [comparewith additive effect and synergistic effect].
- Background level:
- An average or expected amount of a substance or radioactive material in a specificenvironment, or typical amounts of substances that occur naturally in an environment.
- Decomposition or breakdown of a substance through the action of microorganisms (suchas 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 [ananalyte], its metabolite, or another marker of exposure in human body fluids or tissues toconfirm human exposure to a hazardous substance [also see exposure investigation].
- Biologic sampling:
- Measuring hazardous substances in biologic materials (such as blood, hair, urine, orbreath) to determine whether exposure has occurred. A blood test for lead is an exampleof 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 occurredbecause of exposure to a hazardous substance.
- Plants and animals in an environment. Some of these plants and animals might be sourcesof food, clothing, or medicines for people.
- Body burden:
- The total amount of a substance in the body. Some substances build up in the bodybecause they are stored in fat or bone or because they leave the body very slowly.
- [see Community Assistance Panel.]
- Any one of a group of diseases that occur when cells in the body become abnormal andgrow or multiply out of control.
- Cancer risk:
- A theoretical risk for getting cancer if exposed to a substance every day for 70 years (alifetime exposure). The true risk might be lower.
- A substance that causes cancer.
- Case study:
- A medical or epidemiologic evaluation of one person or a small group of people to gatherinformation about specific health conditions and past exposures.
- Case-control study:
- A study that compares exposures of people who have a disease or condition (cases) withpeople who do not have the disease or condition (controls). Exposures that are morecommon 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 SocietyAbstracts Service.
- Central nervous system:
- The part of the nervous system that consists of the brain and the spinal cord.
- [see Comprehensive Environmental Response, Compensation, and LiabilityAct of 1980]
- 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 withacute exposure and intermediate duration exposure]
- Cluster investigation:
- A review of an unusual number, real or perceived, of health events (for example, reportsof cancer) grouped together in time and location. Cluster investigations are designed toconfirm 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 agencieswho work with ATSDR to resolve issues and problems related to hazardoussubstances 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 tohazardous substances, and inform ATSDR on ways to involve the community in itsactivities.
- Comparison value (CV):
- Calculated level of a substance in air, water, food, or soil that is unlikely to causeharmful (adverse) health effects in exposed people. The CV is used as a screeninglevel during the public health assessment process. Substances found in amountsgreater than their CVs might be selected for further evaluation in the public healthassessment process.
- Completed exposure pathway:
- [see exposure pathway].
- Comprehensive Environmental Response, Compensation, and Liability Actof 1980 (CERCLA):
- CERCLA, also known as Superfund, is the federal law that concerns the removal orcleanup of hazardous substances in the environment and at hazardous waste sites.ATSDR, which was created by CERCLA, is responsible for assessing health issues andsupporting public health activities related to hazardous waste sites or other environmentalreleases of hazardous substances. This law was later amended by the SuperfundAmendments and Reauthorization Act (SARA).
- A substance that is either present in an environment where it does not belongor 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 haveoccurred in the past.
- Referring to the skin. For example, dermal absorption means passing through theskin.
- 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 byperson, 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 healthcondition in a defined population.
- 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 drinkcontaminated 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 thebody. 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 resultingchanges in body function or health (response).
- Environmental media:
- Soil, water, air, biota (plants and animals), or any other parts of the environment that cancontain 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 humanexposure can occur. The environmental media and transport mechanism is thesecond part of an exposure pathway.
- United States Environmental Protection Agency.
- Epidemiologic surveillance:
- [see Public health surveillance].
- 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.
- 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 thesubstance 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, notavailable, or missing.
- Exposure investigation:
- The collection and analysis of site-specific information and biologic tests (whenappropriate) 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 itends), and how people can come into contact with (or get exposed to) it. An exposurepathway has five parts: a source of contamination (such as an abandoned business); anenvironmental 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 actuallyexposed). When all five parts are present, the exposure pathway is termed a completedexposure pathway.
- Exposure registry:
- A system of ongoing follow-up of people who have had documented environmentalexposures.
- Feasibility study:
- A study by EPA to determine the best way to clean up environmental contamination. Anumber of factors are considered, including health risk, costs, and what methods willwork well.
- Geographic information system (GIS):
- A mapping system that uses computers to collect, store, manipulate, analyze, anddisplay data. For example, GIS can show the level of a contaminant within acommunity 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.
- Water beneath the earth's surface in the spaces between soil particles and between rocksurfaces [compare with surface water].
- Half-life (t˝):
- The time it takes for half the original amount of a substance to disappear. In theenvironment, the half-life is the time it takes for half the original amount of a substance todisappear when it is changed to another chemical by bacteria, fungi, sunlight, or otherchemical processes. In the human body, the half-life is the time it takes for half theoriginal amount of the substance to disappear, either by being changed to anothersubstance or by leaving the body. In the case of radioactive material, the half life is theamount of time necessary for one half the initial number of radioactive atoms to changeor transform into another atom (that is normally not radioactive). After two half lives,25% of the original number of radioactive atoms remain.
- 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 datacollection, 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 healthquestion or request for information about a potential environmental hazard. Healthconsultations are focused on a specific exposure issue. Health consultations are thereforemore limited than a public health assessment, which reviews the exposure potential ofeach pathway and chemical [compare with public health assessment].
- Health education:
- Programs designed with a community to help it know about health risks and how toreduce these risks.
- Health investigation:
- The collection and evaluation of information about the health of communityresidents. This information is used to describe or count the occurrence of adisease, symptom, or clinical measure and to evaluate the possible associationbetween 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 defectsregistries, and cancer registries) to determine if there is excess disease in a specificpopulation, geographic area, and time period. A health statistics review is a descriptiveepidemiologic study.
- Indeterminate public health hazard:
- The category used in ATSDR's public health assessment documents when a professionaljudgment about the level of health hazard cannot be made because information critical tosuch a decision is lacking.
- The number of new cases of disease in a defined population over a specific time period[contrast with prevalence].
- The act of swallowing something through eating, drinking, or mouthing objects. Ahazardous substance can enter the body this way [see route of exposure].
- The act of breathing. A hazardous substance can enter the body this way [see route ofexposure].
- Intermediate duration exposure:
- Contact with a substance that occurs for more than 14 days and less than a year [comparewith acute exposure and chronic exposure].
- In vitro:
- In an artificial environment outside a living organism or body. For example, sometoxicity testing is done on cell cultures or slices of tissue grown in the laboratory, ratherthan on a living animal [compare with in vivo].
- In vivo:
- Within a living organism or body. For example, some toxicity testing is done on wholeanimals, such as rats or mice [compare with in vitro].
- 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 evaluatewhether an individual's exposure could negatively affect that person'shealth.
- The conversion or breakdown of a substance from one form to another by a livingorganism.
- Any product of metabolism.
- Milligram per kilogram.
- Milligram per square centimeter (of a surface).
- Milligram per cubic meter; a measure of the level of a chemical in a known volume (acubic meter) of air, soil, or water.
- Moving from one location to another.
- Minimal risk level (MRL):
- An ATSDR estimate of daily human exposure to a hazardous substance at or belowwhich 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 usedas predictors of harmful (adverse) health effects [see reference dose].
- State of being ill or diseased. Morbidity is the occurrence of a disease or condition thatalters health and quality of life.
- Death. Usually the cause (a specific disease, a condition, or an injury) is stated.
- A substance that causes mutations (genetic damage).
- A change (damage) to the DNA, genes, or chromosomes of living organisms.
- National Priorities List for Uncontrolled Hazardous Waste Sites (National PrioritiesList or NPL):
- EPA's list of the most serious uncontrolled or abandoned hazardous waste sites in theUnited 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 teststo 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 exposureto contaminated media might be occurring, might have occurred in the past, or mightoccur in the future, but where the exposure is not expected to cause any harmful healtheffects.
- 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 wherepeople have never and will never come into contact with harmful amounts of site-related substances.
- [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 modeldescribes how the chemical gets into the body, where it goes in the body, how it ischanged by the body, and how it leaves the body.
- A craving to eat nonfood items, such as dirt, paint chips, and clay. Some children exhibitpica-related behavior.
- A volume of a substance that moves from its source to places farther away from thesource. Plumes can be described by the volume of air or water they occupy and thedirection they move. For example, a plume can be a column of smoke from a chimney ora substance moving with groundwater.
- Point of exposure:
- The place where someone can come into contact with a substance present in theenvironment [see exposure pathway].
- A group or number of people living within a specified area or sharing similarcharacteristics (such as occupation or age).
- Potentially responsible party (PRP):
- A company, government, or person legally responsible for cleaning up thepollution at a hazardous waste site under Superfund. There may be more thanone PRP for a particular site.
- Parts per billion.
- Parts per million.
- The number of existing disease cases in a defined population during a specific timeperiod [contrast with incidence].
- Prevalence survey:
- The measure of the current level of disease(s) or symptoms and exposures through aquestionnaire that collects self-reported information from a defined population.
- Actions that reduce exposure or other risks, keep people from getting sick, or keepdisease from getting worse.
- Public availability session:
- An informal, drop-by meeting at which community members can meet one-on-one withATSDR staff members to discuss health and site-related concerns.
- Public comment period:
- An opportunity for the public to comment on agency findings or proposed activitiescontained in draft reports or documents. The public comment period is a limited timeperiod 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 ofhazardous substances poses an immediate threat to human health. The advisory includesrecommended measures to reduce exposure and reduce the threat to human health.
- Public health assessment (PHA):
- An ATSDR document that examines hazardous substances, health outcomes, andcommunity concerns at a hazardous waste site to determine whether people could beharmed from coming into contact with those substances. The PHA also lists actions thatneed 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 healthhazard because of long-term exposures (greater than 1 year) to sufficiently high levels ofhazardous 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 byconditions present at the site in the past, present, or future. One or more hazard categoriesmight be appropriate for each site. The five public health hazard categories are no publichealth 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 asummary written in words that are easy to understand. The public health statementexplains how people might be exposed to a specific substance and describes the knownhealth effects of that substance.
- Public health surveillance:
- The ongoing, systematic collection, analysis, and interpretation of health data. Thisactivity 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.
- An unstable or radioactive isotope (form) of an element that can change into anotherelement by giving off radiation.
- Any radioactive isotope (form) of any element.
- [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 ofa substance that is unlikely to cause harm in humans.
- A systematic collection of information on persons exposed to a specific substance orhaving specific diseases [see exposure registry and disease registry].
- Remedial investigation:
- The CERCLA process of determining the type and extent of hazardous materialcontamination at a site.
- Resource Conservation and Recovery Act (1976, 1984) (RCRA):
- This Act regulates management and disposal of hazardous wastes currentlygenerated, treated, stored, disposed of, or distributed.
- RCRA Site Assessment. An assessment required by RCRA to identify potentialand actual releases of hazardous chemicals.
- [see reference dose]
- The probability that something will cause injury or harm.
- Risk reduction:
- Actions that can decrease the likelihood that individuals, groups, or communities willexperience 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 ofexposure are breathing [inhalation], eating or drinking [ingestion], or contact withthe skin [dermal contact].
- Safety factor:
- [see uncertainty factor]
- [see Superfund Amendments and Reauthorization Act]
- A portion or piece of a whole. A selected subset of a population or subset of whatever isbeing studied. For example, in a study of people the sample is a number of people chosenfrom a larger population [see population]. An environmental sample (for example, a smallamount of soil or water) might be collected to measure contamination in the environmentat a specific location.
- Sample size:
- The number of units chosen from a population or an environment.
- A liquid capable of dissolving or dispersing another substance (for example, acetone ormineral 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 anexposure pathway.
- Special populations:
- People who might be more sensitive or susceptible to exposure to hazardoussubstances because of factors such as age, occupation, sex, or behaviors (forexample, cigarette smoking). Children, pregnant women, and older people areoften considered special populations.
- A person, group, or community who has an interest in activities at a hazardous waste site.
- A branch of mathematics that deals with collecting, reviewing, summarizing, andinterpreting data or information. Statistics are used to determine whether differencesbetween study groups are meaningful.
- A chemical.
- Substance-specific applied research:
- A program of research designed to fill important data needs for specific hazardoussubstances identified in ATSDR's toxicological profiles. Filling these data needswould allow more accurate assessment of human risks from specific substancescontaminating the environment. This research might include human studies orlaboratory experiments to determine health effects resulting from exposure to agiven hazardous substance.
- [see Comprehensive Environmental Response, Compensation, and LiabilityAct 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 ofATSDR. CERCLA and SARA direct ATSDR to look into the health effects fromsubstance exposures at hazardous waste sites and to perform activities including healtheducation, health studies, surveillance, health consultations, and toxicological profiles.
- Surface water:
- Water on the surface of the earth, such as in lakes, rivers, streams, ponds, andsprings [compare with groundwater].
- [see public health surveillance]
- A systematic collection of information or data. A survey can be conducted to collectinformation from a group of people or from the environment. Surveys of a group ofpeople can be conducted by telephone, by mail, or in person. Some surveys are done byinterviewing a group of people [see prevalence survey].
- Synergistic effect:
- A biologic response to multiple substances where one substance worsens the effect ofanother substance. The combined effect of the substances acting together is greater thanthe sum of the effects of the substances acting by themselves [see additive effect andantagonistic effect].
- A substance that causes defects in development between conception and birth. Ateratogen is a substance that causes a structural or functional birth defect.
- Toxic agent:
- Chemical or physical (for example, radiation, heat, cold, microwaves) agents that, undercertain circumstances of exposure, can cause harmful effects to living organisms.
- Toxicological profile:
- An ATSDR document that examines, summarizes, and interprets information about ahazardous substance to determine harmful levels of exposure and associated healtheffects. A toxicological profile also identifies significant gaps in knowledge on thesubstance and describes areas where further research is needed.
- The study of the harmful effects of substances on humans or animals.
- An abnormal mass of tissue that results from excessive cell division that is uncontrolledand 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. Forexample, 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, fordifferences between animals and humans, and for differences between a LOAEL and aNOAEL. Scientists use uncertainty factors when they have some, but not all, theinformation from animal or human studies to decide whether an exposure will cause harmto people [also sometimes called a safety factor].
- Urgent public health hazard:
- A category used in ATSDR's public health assessments for sites where short-termexposures (less than 1 year) to hazardous substances or conditions could result in harmfulhealth effects that require rapid intervention.
- Volatile organic compounds (VOCs):
- Organic compounds that evaporate readily into the air. VOCs includesubstances such as benzene, toluene, methylene chloride, and methyl chloroform.
Other glossaries and dictionaries:
Environmental Protection Agency (http://www.epa.gov/OCEPAterms/)
National Center for Environmental Health (CDC)
National Library of Medicine (NIH)
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
ATSDR health assessors use comparison values (CVs) as screening tools to evaluateenvironmental data that are relevant to the exposure pathways. CVs representmedia-specific contaminant levels that are much lower than exposure levelsobserved to cause adverse health effects. In that way, CVs are protective of publichealth in essentially all exposure situations. If the levels in the exposure medium areless than the CV, the exposures are not of health concern and no further analysis ofthe pathway is required. However, while levels below the CV are not expected tolead to any observable health effect, it should not be inferred that a level greaterthan the CV will necessarily lead to adverse effects. Depending on site-specificenvironmental exposure factors (for example, duration of exposure) and activities ofpeople that result in exposure (time spent in area of contamination), exposure tolevels above the CV may or may not lead to a health effect. Therefore, ATSDR'sCVs are not used to predict the occurrence of adverse health effects. Rather, theyare used by ATSDR to select contaminants for further evaluation to determine thepossibility 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 excesscancer in a million (10-6) persons exposed over a 70-year life span. ATSDR's CREGs arecalculated from EPA's cancer slope factors (CSFs).
- Environmental Media Evaluation Guide (EMEG):
- EMEGs are based on ATSDR minimal risk levels (MRLs) and factor inbody weight and ingestion rates. An EMEG is an estimate of daily human exposure to achemical (in mg/kg/day) that is likely to be without noncarcinogenic health effectsover a specified duration of exposure to include acute, intermediate, and chronicexposures.
- Reference Media Evaluation Guides (RMEG):
- ATSDR derives RMEGs from EPA's oral reference doses (RfDs). The RMEG representsthe level in water or soil at which daily human exposure is unlikely to result in adversenoncarcinogenic effects.
- EPA's Region III Risk-Based Level (RBC):
- The U.S. Environmental Protection Agency (EPA) combines RfDs andCSF 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, whicheveroccurs 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 themaximum 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 andEPA's RfDs, and EPA's CSFs. These guidelines are based on the no-observedadverse effect levels (NOAEL), lowest-observed adverse effect levels (LOAELs), orthe cancer effect levels (CELs) reported for a contaminant in the toxicologicliterature. A description of these terms is provided:
- Minimal Risk Levels (MRL):
- MRLs are estimates of daily human exposure to a chemical (i.e., dosesexpressed in mg/kg/day) that are unlikely to be associated with any appreciable risk ofdeleterious noncancer effects over a specified duration of exposure. MRLs arecalculated using data from human and animal studies and are reported for acute (< 14days), 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-timeexposure of human populations to a possible hazard that is not likely to cause harm to theperson.
- 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 limiton the likelihood that lifetime exposure to a particular chemical could lead toexcess 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 harmfulhealth 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).
Estimates of Human Exposure Doses and Determination of Health Effects
The health hazards that could plausibly result from exposures to contaminantsdetected at St. Juliens Creek Annex and nearby areas are discussed in furtherdetail in this appendix. It is important to note that public health hazards fromenvironmental contamination happen only when (a) people are exposed to thecontaminated media and (b) the exposure is at high enough doses to result in aneffect.
As an initial screen, ATSDR evaluated available data to determine whethercontaminants were accessible to the public or were above ATSDR's comparisonvalues. The majority of detected contaminants were either not accessible to thepublic or fell at or below comparison values and were not evaluated further.Exposure situations with contaminants above comparison values or that hadinsufficient environmental data were deemed worthy of further evaluation. Theseexposure situations are:
- Past exposures to contaminants in on-site soil.
- Past exposure to contaminants in on-site sediment (Blows Creek and marshareas) and past and current exposure to contaminants in off-site sedimentat St. Juliens Creek and the Elizabeth River.
- Past exposure to contaminants in on-site surface water (Blows Creek andmarsh areas).
Deriving Exposures Doses
After identifying contaminants in site media above comparison values and identifyingpotential pathways of exposure, ATSDR further evaluates exposures to detectedcontaminants considering information about exposures combined with scientificinformation from the toxicologic and epidemiologic literature. If necessary, ATSDRestimates exposure doses, which are estimates of how much contaminant a person isexposed to on a daily basis. Variables considered when estimating exposure doses includethe contaminant level in the environmental media, the exposure amount (how much of thesubstance the person was actually exposed to), the exposure frequency (how often), andthe exposure duration (how long).
Evaluating Potential Health Hazards
The estimated exposure doses can be used to evaluate potential noncancer and cancereffects associated with contaminants detected in site media. When evaluatingnoncancer effects, ATSDR compares the estimated exposure dose to standard toxicityvalues, including ATSDR's minimal risk levels (MRLs) and the U.S. EnvironmentalProtection Agency's reference doses (RfDs), to evaluate whether adverse effects mayoccur. The chronic MRLs and RfDs are estimates of daily human exposure to a substancethat is likely to be without appreciable risk of adverse noncancer effects over a specifiedduration. The chronic MRLs and RfDs are conservative values, based on the levels ofexposure 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 accountfor variation in the human population and uncertainty involved in extrapolating humanhealth effects from animal studies. ATSDR also reviews the toxicologic literature andepidemiology studies to further evaluate the weight of evidence for adverse effects.
ATSDR also evaluates the likelihood that site-related contaminants will cause cancer inpeople who would not otherwise develop it. As an initial screen, ATSDR calculates atheoretical increase of cancer cases in a population over a lifetime of exposure usingEPA's cancer slope factors (CSFs), which represent the relative potency of carcinogens.This is accomplished by multiplying the calculated exposure dose by a chemical-specificCSF. CSFs are developed using data from studies of animals or humans exposed toknown doses of a particular chemical. Because CSFs are derived using mathematicalmodels which apply a number of uncertainties and conservative assumptions, riskestimates generated by using CSFs tend to be overestimated. Although no risk of canceris 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 in10,000 to 1,000,000 exposed persons), based on conservative assumptions aboutexposure, to determine the likelihood of excess cancer resulting from this exposure.
ATSDR also compared an estimated lifetime exposure dose to available cancer effectlevels (CELs). An estimated lifetime exposure dose is defined as a dose that producessignificant increases in the incidence of cancer or tumors. The CEL is the lowest dose ofa chemical in a study, or group of studies, that was found to produce increased incidencesof cancer (or tumors). In addition, genotoxicity studies are also reviewed to understandfurther the extent to which a chemical might be associated with cancer outcomes. Thisprocess enables ATSDR to weigh the available evidence in light of uncertainties andoffer perspective on the plausibility of harmful health outcomes under site-specificconditions.
Using other methods to evaluate potential health hazards
When dealing with exposure to lead, ATSDR uses an additional approach to thetraditional methodologies described above. A substantial part of human health effectsdata for lead are expressed in terms of blood lead level rather than exposure dose. TheCenters for Disease Control and Prevention (CDC) has determined that health effectsare more likely to be observed if blood lead levels are at or above 10 µg/dL. ATSDRdeveloped an approach that uses media-specific uptake parameters to estimate whatcumulative blood lead level might result from exposure to a given level ofcontamination. However, historical blood lead data were available for St. JuliensCreek Annex. Blood lead data are expected to provide a more accurate indicator ofpossible health effects associated with lead. Therefore, this public health assessmentdoes 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 sedimentsamples. These substances are important minerals that maintain basic life functions;therefore, their presence in the sediment is not of health concern. They are found inmany foods, such as milk, bananas, and table salt. Ingestion of these essentialnutrients at the levels detected found at this site will not result in harmful healtheffects.
Estimated Exposure Doses for Incidental Ingestion of On-Site Soil
Volatile organic compounds, pesticides, and metals and other inorganic elementswere detected in on-site soil at landfills and other industrial areas at St. Juliens CreekAnnex, at levels above ATSDR CVs for soil. The primary exposure pathway ofconcern is through incidental ingestion of soil for individuals, primarily teenagers oryoung adults exploring industrial areas of St. Juliens Creek Annex. ATSDR assumedthat young children would not have access to the industrial areas because most arefar away from the housing areas and unlikely to be visited by unsupervised children.
ATSDR estimated exposure doses to contaminants in the soil. Because site-specificinformation about exposure was not available, ATSDR used protective assumptionswhen deriving the doses. ATSDR assumed that an adult might incidentally ingest 100mg/day of soil (EPA 1997), which is the default rate generally used when evaluatingadult soil exposure. This is a conservative or protective assumption because people arenot 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 detectedlevels 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 exposuredoses, respectively, to these contaminants in the soil at on-site locations. ATSDR usedthe following equation and assumptions to estimate the exposure dose for ingestion ofon-site soil:
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)
ATSDR compared the estimated dose for each contaminant to its respective MRL orRfD. The estimated doses to an adult for all contaminants in on-site soil were belowthe corresponding MRL or RfD. Considering the conservative nature of ourestimates, exposures to the contaminants in on-site soil is unlikely to be of publichealth concern.
Children likely did not have access to on-site soil, but they lived in on-site housingareas where they were likely exposed to higher levels of lead in soil and dust in theirimmediate environment. The estimated contribution to blood lead levels for a childliving in the on-site housing areas is discussed in the "Community Health Concerns"portion of this PHA.
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 atthe detected level. All cancer risk levels (10-5 to 10-7) are safely below the range consideredto pose excess cancer risk. ATSDR also compared the estimated cancer dose for acontaminant to the lowest CEL reported in the toxicologic literature to further assess thepotential for cancer effects to occur. The estimated doses ranged from 40 to 330,000,000times lower than the levels at which cancer has been observed in human or animalstudies. ATSDR therefore concludes that people who incidentally ingest soil duringactivities at the on-site industrial or Waste Disposal Area Areas are not at increasedlikelihood 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 inorganicelements were detected in sediment at the Blows Creek located at St. Juliens at levelsabove ATSDR CVs for soil. Elevated levels of these contaminants were also detectedin sediment at off-site locations along St. Juliens Creek and the Elizabeth River, atlevels above ATSDR CVs for soil. They were also detected on-site in shallow marshareas near site landfills, although ATSDR expects that individuals would haveaccessed these areas less frequently. Adults and children living in on-site housingcould have come in contact with contaminants in sediment while wading alongBlows Creek in the past or from incidental ingestion during wading and otherrecreational activities at the St. Juliens Creek and the Elizabeth River. The primaryexposure pathway of concern is incidental ingestion of contaminants. Most of thecontaminants 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 incidentalingestion of sediment containing aluminum, aldrin, antimony, arsenic, dieldrin, orPAHs. In estimating the exposure doses, ATSDR assumed that an adult mightincidentally ingest 100 mg/day of sediment and that a child might ingest 200 mg/dayof sediment (EPA 1997). These intake rates are the default rates generally usedwhen evaluating soil/sediment exposures. As such, it is likely a conservativeassumption because people are not likely to contact this amount of sediment fromthe same location on a daily basis.
Tables C-3 and C-4 summarize the estimated exposure doses to contaminants inthe sediment at on-site and off-site locations. The following presents the equationand assumptions used to estimate the exposure dose:
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)
ATSDR compared the estimated dose for each contaminant to its respective MRL orRfD. The estimated dose to a child or an adult, for contaminants in on-site and off-sitesediment, never exceeded the corresponding MRL or RfD. Based on these findings,ATSDR does not expect that individuals who incidentally ingested sediment whilevisiting these waterways will develop adverse noncancer health effects.
Lead was detected in sediment. However, as discussed earlier in this appendix, ATSDRdid not evaluate the blood lead levels that could result from these detected levels of leadin 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 werelikely 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 housingareas is discussed in the "Community Health Concerns" portion of this PHA. Exposure tolead in sediment is not likely to result in adverse health effects.
EPA has classified aldrin, arsenic, dieldrin, and PAHs as human or probable humancarcinogens via the oral route of exposure. ATSDR estimated theoretical cancer risk fromcontacting each of these contaminants at the detected level. All cancer risk levels (10-5 to10-7) are safely below the range considered to pose excess cancer risk. ATSDR alsocompared the estimated cancer dose for a contaminant to the lowest CEL reported in thetoxicologic literature to further assess the potential for cancer effects to occur. Theestimated doses were more than 190 to 35,000,000 times lower than the levels at whichcancer has been observed in human or animal studies. ATSDR therefore concludes thatpeople who incidentally ingest sediment during activities at the on-site or nearby waterbodies 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 surfacewater in Blows Creek located on site and at marsh areas near the on-site landfills atlevels above ATSDR CVs. Children living in on-site housing could have come incontact with contaminants in surface water at Blows Creek in the past. Adults andolder children also could have contacted contaminants in the marsh areas near theon-site landfills. The primary exposure pathway of concern is through incidentalexposure of water while visiting or using the water for recreation. ATSDR evaluatedthe health effects that could possibly result from incidental ingestion of surfacewater containing these constituents. Most of the contaminants are not readilyabsorbed through the skin, therefore, posing minimal, if any, health risk fromdermal contact.
ATSDR estimated doses for aluminum, antimony, arsenic, beryllium, cadmium,chromium, cobalt, copper, manganese, nickel, thallium, vanadium, and zinc. Inderiving 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). ATSDRassumed that people were directly exposed to the surface water twice a week, allyear long. ATSDR also assumed that an adult could have been exposed to thedetected 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 notlikely to visit the surface water all year, swim frequently in these areas, orconsistently ingest that much surface water while swimming.
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)
ATSDR compared the estimated doses to the respective MRL or RfD. In all cases, theestimated dose to an adult and child for a contaminant was similar to (i.e., mercury) orbelow its corresponding MRL or RfD. Therefore, even assuming daily exposure to themaximum detected level of these contaminants, exposures are unlikely to be of publichealth 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 levelsof 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 areaswhere they were likely exposed to higher levels of lead in soil and dust in their immediateenvironment. 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 achild playing in that area.
EPA has classified arsenic as a human carcinogen via the oral route of exposure.ATSDR estimated theoretical cancer risk from accidentally ingesting water duringswimming with detected levels of arsenic. The cancer risk level (10-5) is safely below therange considered to pose increased cancer risk. ATSDR also compared the estimatedcancer dose for a contaminant to the lowest CEL reported in the toxicologic literatureto further assess the potential for cancer effects to occur. The estimated dose is about64 times lower than the lowest level at which cancer has been observed in humanstudies. With this information, ATSDR concludes that people who incidentally ingestsurface water while swimming or during other recreational activities are not atincreased likelihood of developing cancer.
Agency for Toxic Substances and Disease Registry (ATSDR). 1996. Toxicologicalprofile for PAHs. Atlanta: US Department of Health and Human Services. September1996.
ATSDR. 1999. Toxicological profile for lead (update). Atlanta: US Department ofHealth and Human Services. July 1999.
ATSDR. 2000a. Toxicological profile for arsenic. Atlanta: US Department of Health andHuman Services. September 2000.
ATSDR. 2000b. Toxicological profile for polychlorinated biphenyls. Atlanta: USDepartment 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 ofHealth and Human Services. September 2002.
EPA. 1997. Exposure Factors Handbook. 1997 August.http://www.epa.gov/ncea/exposfac.htm.
|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 |
|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 |
|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|
|mg/kg/day||milligrams contaminant per kilogram body weight per day;|
|MRL||ATSDR minimal risk level;|
|ppb||parts per billion;|
|RfD||EPA reference dose.|
|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)
|CEL||ATSDR cancer effect level|
|mg/kg/day||milligrams contaminant per kilogram body weight per day;|
|ppm||parts per million|
|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)|
|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|
|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.
|mg/kg/day||milligrams contaminant per kilogram body weight per day;|
|MRL||ATSDR minimal risk level;|
|ppb||parts per billion;|
|RfD||EPA reference dose.|
|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)
|CEL||cancer effect level|
|mg/kg/day||milligrams contaminant per kilogram body weight per day;|
|ppb||parts per billion|
|Contaminant||On-Site Surface Water||Health Guideline (mg/kg/day)||Basis for Health Guideline|
|Maximum Level (ppb)||Estimated Exposure Dose (mg/kg/day)|
|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|
|Nickel||364||0.000223||0.02||Chronic oral RfD|
|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.
|mg/kg/day||milligrams contaminant per kilogram body weight per day;|
|MRL||ATSDR minimal risk level;|
|ppb||parts per billion;|
|RfD||EPA reference dose.|
|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)
|CEL||cancer effect level|
|mg/kg/day||milligrams contaminant per kilogram body weight per day;|
|ppb||parts per billion|
ATSDR received several editorial comments on the public comment release of thePublic Health Assessment for St. Juliens Creek Annex. Those comments wereaddressed in this version.
ATSDR also received some specific comments that are addressed below. We did notreceive any comments from individual citizens or citizen groups.
The first two comments refer to the warning signs placed near the wharf area alongthe 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 ofthe history and rationale for the current wording. Navy personal indicate that while thepotential for UXO to exist in the sediment can not be ruled out and metal anomalies weredetected below the surface of the sediment, no direct evidence of UXO has beenidentified. The anomalies exist beneath the surface of soft sediment at a depth where theycould not be safely removed without dredging. Sediment samples indicate the chemicalconcentrations are below levels of health concern. Trace amounts of 1,3-dinitrobenzenewas detected in some of the sediment samples. This chemical could represent atrinitrotoluene (TNT) production impurity, however it is also used in commercialproducts and could be present in the sediment from other sources. TNT was not detectedin the sediment. Because the Navy has not identified sufficient evidence to confirm thatUXO is present in the sediment there are no immediate plans to continue theinvestigation. Because it is possible that UXO could be present beneath the surface of thesediment 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 specificrecommendations that site managers need to follow. ATSDR evaluates each situationto ensure that the method proposed or enacted by the site manager is likely to preventexposures to the community that would be expected to cause harm. Although theexisting signs do not specifically identify that UXO could be present in the sedimentnear 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, ifit 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.
EPA 2003. U.S. EPA Seminar on Indoor Air Vapor Intrusion. February 25-26, 2003.Atlanta, GA