ST. MARKS REFINERY
ST. MARKS, WAKULLA COUNTY, FLORIDA
In June 2002, the Florida Department of Environmental Protection (DEP) asked the Florida Department of Health (DOH) if concentrations of chlorinated dibenzodioxins (CDD, or "dioxin") and pentachlorophenol (PCP) in soil and water samples at a former petroleum refinery site in St. Marks, Florida are hazardous to human health. The Florida DOH, through a cooperative agreement with the federal Agency for Toxic Substances and Disease Registry (ATSDR) in Atlanta, Georgia, evaluates the public health significance of hazardous waste sites in Florida. This is the first review of the St. Marks Refinery site by either the Florida DOH or the ATSDR.
The St. Marks Refinery site is on Woodville Highway (Highway 363) in the town of St. Marks in Wakulla County (Figure 1). Built in 1954, the refinery processed crude oil for jet fuel and asphalt.The site is now owned by American International Petroleum, Inc. Seminole Refining Corporationowned the refinery from 1985 to 1992. The facility consists of a refined product storage area, aprocess area, a waste asphalt pond, petroleum tanks and refinery equipment. The facility closed in1985. Tallahassee's Purdom power plant and Murphy Oil are south and north of the refinery,respectively. The St. Marks historic railroad state trail is west of the site. The St. Marks River is eastof the site. Wetlands with winding tributaries throughout are northeast of the site. A stormwateroutfall on the east side leads to a drainage ditch which empties into the St. Marks River (Figure 2).A dock on the St. Marks River allowed for barge transport of crude petroleum and finished product.
Testing of this property found elevated concentrations of dioxin, pentachlorophenol,benz[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, dibenz[a,h]anthracene, ideno[1,2,3-cd]pyrene, 2-methylnapthalene, 2-methylphenol, aluminum, arsenic, manganese and benzene. InApril 2002, the Florida DEP found chlorinated dibenzodioxins (CDD, or "dioxin") andpentachlorophenol (PCP) on the site. In June 2002, they founddioxin off the site in the St. MarksRiver sediments. The Idacon wood treatment facility north of the site may be the source of PCP. Thedioxin may be from an incinerator operated on the site prior to 1985. The highest dioxin levels arein a tributary near the crude oil storage area. In June 2002, the Wakulla County Health Departmentwent door-to-door and confirmed there are no private wells within a half mile of the site. All nearbyresidences are on City of Tallahassee water.
For the purposes of this report, the Florida DOH calculated exposure doses for adults. Based oninterviews with site workers and local residents, there is no evidence that children currently are orever have been exposed to contaminants on the St. Marks Refinery site.
Currently, the Florida DEP is remediating the entire site. In June 2002, they shared with the FloridaDOH a report that includes soil, sediment and groundwater results from April/May 2002. The FloridaDOH will evaluate the potential for public health consequences. They will also evaluate fish andcrab tests from the Florida Fish and Wildlife Commission and the Florida DEP and determine if health advisories are necessary.
The Florida DOH compared soil and groundwater sample results for dioxin, pentachlorophenol, andother contaminants to health-based screening values. In addition to dioxin and pentachlorophenol,the Florida DOH evaluated potential health effects from exposure to eleven other contaminants thatexceeded screening values. These were benz[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene,dibenz[a,h]anthracene, ideno[1,2,3-cd]pyrene, 2-methylnapthalene, 2-methylphenol, aluminum,arsenic, manganese and benzene (Tables 1 and 2).
The screening values or comparison values serve to narrow the focus of the health consultation tothose contaminants most important to public health. Screening values are health protective numbers,but do not necessarily mean that concentrations in excess of these values will cause illness.
The Florida DOH calculated ingestion and inhalation exposure rates for adults (workers and visitorsto the site) assuming a "worst-case" scenario of 8 hour exposures per day, 350 days per year, for 30years. Generally, an exposure rate (also called a daily dose) is given in milligrams of chemical perkilogram of body weight per day (mg/kg/day). A milligram is one-thousandth of a gram (a raisin orpaperclip weigh about one gram). A kilogram is about two pounds. The Florida DOH assumed thata 70 kilogram adult accidentally ingests 100 milligrams of soil per day.
According to the ATSDR, only 2.5 percent of the estimated daily background exposure to dioxin inthe general U.S. population comes from contaminated soil, contaminated water, or contaminateddust, while 97 percent comes from food sources (ATSDR 1998).
The most toxic form of dioxin is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Exposure to largeamounts of 2,3,7,8-TCDD may cause chloracne, a skin disease resembling acne. Other skin effectsmay include rashes, discoloration and hair loss. Additional health effects may include possible liverdamage and changes in glucose metabolism and hormone levels. Animal studies have shown anincreased risk of cancer from exposure to 2,3,7,8-TCDD. The Department of Health and HumanServices (DHHS) has determined that 2,3,7,8-TCDD may reasonably be anticipated to cause cancer(ATSDR 1998).
The ATSDR screening value for dioxin in soil is 0.00005 parts per million (ppm). Two soil samples(0 - 24 inches below land surface - BLS) exceeded the ATSDR adult screening value. The levelswere 0.00028 ppm and 0.105 ppm (Table 1).
The ATSDR screening value for dioxin in water is 0.00003 ppm. Two groundwater samplesexceeded the ATSDR adult screening value. The levels were 0.041 ppm and 0.173 ppm (Table 2).
There is no screening value for dioxin in sediment. The soil dioxin level used to determine potentialhealth risks is greater than the sediment dioxin levels measured at the site. Since people are morelikely to be exposed to contaminated soil than sediment (because sediment is usually under water),sediment exposure was not calculated at this time. The Florida DOH has performed a HealthConsultation for dioxin in fish, which is a more likely exposure route for dioxin in humans.
Pentachlorophenol (PCP) is a manufactured chemical not found naturally in the environment.Pentachlorophenol exposure happens mostly to workers at lumber mills and wood treatment facilities(ATSDR 2001). Although it is not used in consumer products anymore, PCP is still used as a woodpreservative in power line poles, railroad ties, cross arms and fence posts. Short-term exposures tolarge amounts of PCP, or long-term exposures to small amounts of PCP, may effect the liver,kidneys, blood, lungs, nervous system, immune system and gastrointestinal tract. Direct contact withPCP can irritate the skin, eyes and mouth. There is little evidence that PCP causes cancer in humans. Animal studies show an increased risk of cancer in the liver and adrenal glands of mice afterexposure to large amounts of PCP (ATSDR 2001).
The ATSDR screening value for pentachlorophenol in soil is 700 parts per million (ppm) for adults. Two soil samples on this site (0 - 24 inches BLS) exceeded the ATSDR adult screening value. Thelevels were 1,190 ppm and 2,420 ppm (Table 1).
The ATSDR screening value for pentachlorophenol in water is 0.2 ppm for adults. Two groundwatersamples exceeded the ATSDR adult screening value. The levels were 6.7 ppm and 2.4 ppm (Table 2).
The Florida DOH calculated a dose and compared it to doses of dioxin and pentachlorophenolknown to cause illness in people. The Florida DOH also calculated doses for eleven othercontaminants and compared them to doses known to cause illness from these chemicals.
Non-Cancer Health Effects
The Florida DOH found that accidentally ingesting contaminated surface soil at the maximum levelsfor thirty years for all of the contaminants found on the site would not cause any non-cancer illnessfor adult workers and visitors. The Florida DOH also found that inhaling contaminated dust at themaximum levels for 30 years for all the contaminants found on the site would not cause any non-cancer illness in adult workers and visitors.
The Florida DOH found that ingesting contaminated groundwater at the maximum levels for 30years for all the contaminants found on the site could cause non-cancer illness in adults. The dosesfor pentachlorophenol, arsenic and manganese all exceeded the level shown to cause illness inanimals (see Table 3). However, a door-to-door survey of residents living in the St. Marks area, theCity of Tallahassee supplies drinking water for the town, and groundwater wells are only used forirrigation purposes. There is no evidence to suggest that any local residents are drinkingcontaminated groundwater from the St. Marks Refinery site.
Pentachlorophenol - Drinking groundwater from under the site at the maximum level for 30 yearsequals or exceeds the dose shown to cause increased relative weights of kidneys and livers,decreased antibody response and negative endocrine and reproductive responses in animals.
Arsenic - Drinking groundwater from under the site at the maximum arsenic level for 30 years couldcause increased skin discoloration, increased risk of dying from heart disease, increased diarrhea andnausea, and some liver damage.
Manganese - Drinking groundwater from under the site at the maximum manganese level for 30years could cause mild neurologic signs.
Other Contaminants - Very little information was available on potential health effects from exposureto benz[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, dibenz[a,h]anthracene, ideno[1,2,3-cd]pyrene, 2-methylnapthalene, and 2-methylphenol. Because of a lack of studies on the healtheffects of these contaminants, adverse reactions could not be adequately described.
Arsenic, pentachlorophenol and benzene are human carcinogens. Ingestion of arsenic,pentachlorophenol and benzene in groundwater under the St. Marks Refinery for 30 years couldincrease the risk for cancer.
Arsenic - One human study demonstrated that the dose of arsenic in groundwater similar to the levelmeasured at the St. Marks refinery could increase the risk of lung cancer after 30 years of exposure.Long term (chronic) ingestion of arsenic-contaminated groundwater at the St. Marks Refinery couldresult in a "moderate" increased risk of cancer.
Pentachlorophenol - One human study demonstrated that the dose of PCP in groundwater similar tothe levels at the St. Marks Refinery could increase the risk for non-Hodgkins lymphoma and softtissue sarcoma after 30 years of exposure. The exposure pathway for the study was fish consumptionand drinking well water. Long term (chronic) ingestion of pentachlorophenol-contaminatedgroundwater at the St. Marks Refinery could result in a "high" increased risk of cancer.
Benzene - Long term (chronic) ingestion of benzene-contaminated groundwater at the St. MarksRefinery could result in a "low" increased risk of cancer after 30 years of exposure.
Dioxin - While 2,3,7,8-TCDD, one of seventeen dioxin forms, is a probable human carcinogen, theother sixteen congeners have not been established as suspected human carcinogens. When theFlorida DOH looked at the highest level of 2,3,7,8-TCDD in soil and groundwater and calculateda chronic (30 year) exposure dose, the level of 2,3,7,8-TCDD was too low to exhibit a statistically-significant increase in the occurrence of cancer or other adverse health effect. Consequently, whenall seventeen forms of dioxin were factored together into an exposure dose, no likely increase incancer or other illness is expected.
Other Contaminants - There is insufficient information to determine if 2-methylnapthalene, 2-methylphenol, aluminum, and manganese cause cancer in humans or animals. Benz[a]anthracene,benzo[a]pyrene, benzo[b]fluoranthene, dibenz[a,h]anthracene and ideno[1,2,3-cd]pyrene are allpolycyclic aromatic hydrocarbons (PAHs) which have been shown to cause tumors in animals. Theyare all in a class of suspected human carcinogens. However, none of the doses were high enoughto have the potential to cause cancer in the worst-case scenario tested for adult workers and visitors.
Adults exposed to contaminated soil and dust on site for 30 years would not be expected to sufferany adverse health effects. Adults who drink two liters of groundwater from the site each day for30 years and which is contaminated at the highest level measured may suffer adverse health effects,including an increased risk of cancer.
The Florida DOH recommends that people not drink the contaminated groundwater from the St.Marks Refinery site. Based on a door-to-door survey of residents living in the St. Marks area, theCity of Tallahassee supplies drinking water for the town, and groundwater wells are only used forirrigation purposes. There is no evidence to suggest that any local residents are drinkingcontaminated groundwater from the St. Marks Refinery site.
The Florida DOH recommends additional sampling to further characterize the lateral extent ofcontamination of the surface soil and groundwater, including off site contamination (surroundingproperty). Additional analyses of surface soil should include samples from no more than threeinches below land surface ( < 3 inches BLS). Residents have reported rainwater runoff from the St.Marks facility draining into ditches and yards around the site. Off-site surface soil sampling wouldlikely detect contaminants carried from the site to off-site locations. Shallow groundwater can also carry contaminants from the site to off-site locations.
The ATSDR and the Florida DOH, through the ATSDR's Child Health Initiative, recognize that incommunities faced with the contamination of their environment, the unique vulnerabilities of infantsand children demand special attention. Children are at a greater risk than are adults for certain kindsof exposure to hazardous substances emitted from waste sites. Because they play outdoors andbecause they often carry food into contaminated areas, children are more likely to be exposed tocontaminants in the environment. Children are shorter than adults, which means they breathe dust,soil, and heavy vapors (such as those released by metallic mercury) close to the ground. They arealso smaller, resulting in higher doses of chemical exposure per body weight. If toxic exposuresoccur during critical growth stages, the developing body systems of children can sustain permanentdamage. Probably most important, however, is that children depend on adults for risk identificationand risk management, housing, and access to medical care. Thus, adults should be aware of publichealth risks in their community, so they can accordingly guide their children.
For the purposes of this report, the Florida DOH calculated exposure doses for adults. Based oninterviews with site workers and local residents, there is no evidence that children currently are orever have been exposed to contaminants on the St. Marks Refinery site. In the future, after off sitesampling and analysis is complete, the Florida DOH will evaluate the potential for adverse healtheffects to children from exposure to site related contaminants.
Sensitive populations exhibit a different or enhanced response to contaminants than will mostpersons exposed to the same level of a contaminant in their environment. Reasons may includegenetic makeup, age, health and nutritional status, and exposure to other toxic substances. Personsunusually susceptible to contaminant exposures include unborn children, children, the elderly, andpersons with diseases, compromised immune systems and/or dietary insufficiencies. With regardto the St. Marks Refinery site, people most susceptible to the contaminants in the groundwater wouldbe those who are immunocompromised, have existing liver, kidney or heart disease, or who already have debilitating conditions such as cancer.
The St. Marks Refinery site is categorized as a "No Apparent Public Health Hazard" for adultworkers and visitors. Workers are not being exposed to contaminants at doses high enough to causeadverse health effects.
The St. Marks Refinery site is categorized as an "Indeterminate Public Health Hazard" for thesurrounding community. There is no evidence that workers or local residents are being exposed togroundwater contamination from the St. Marks Refinery site. However, the extent of contaminationof surface soil and groundwater has not been adequately characterized. Residents have reportedrainwater runoff from the St. Marks facility draining into ditches and yards around the site. Off-sitesurface soil sampling would likely detect contaminants carried from the site to off-site locations. Shallow groundwater can also carry contaminants from the site to off-site locations. Future testingshould include more surface soil samples (< 3 inches BLS) and groundwater samples to delineatethe lateral extent of on-site and off-site contamination.
Unremediated groundwater associated with the St. Marks Refinery site should not be used as adrinking water source. The level of contamination in the groundwater on the site can contribute to a dose high enough to cause observable health effects and/or cancer.
Collect and analyze additional surface soil (< 3 inches BLS) and groundwater samples to furthercharacterize the lateral extent of on site and off site contamination. Analyze for dioxin (CDD),base/neutral/acid extractable organic compounds (including PCP), volatile organic compounds (VOCs) and total metals (TAL metals).
Avoid drinking or otherwise coming into contact with contaminated groundwater from the St. Marks Refinery site.
The Florida DOH will continue to assist the Florida DEP and the St. Marks community by reviewing additional environmental data as they become available.
Florida DEP Secondary Interim Summary of Investigation Activities at the St. Marks Refinery Site,Ecology $ Environment, Inc., June 2002.
ATSDR, 1998. Toxicological Profile for Chlorinated Dibenzo-p-Dioxins. Agency for ToxicSubstances and Disease Registry, U.S. Department of Health and Human Services.
ATSDR, 2001. Toxicological Profile for Pentachlorophenol. Agency for Toxic Substances andDisease Registry, U.S. Department of Health and Human Services.
ATSDR, 1999. Toxicological Profile for Aluminum. Agency for Toxic Substances and DiseaseRegistry, U.S. Department of Health and Human Services.
ATSDR, 2000. Toxicological Profile for Arsenic. Agency for Toxic Substances and DiseaseRegistry, U.S. Department of Health and Human Services.
ATSDR, 1997. Toxicological Profile for Benzene. Agency for Toxic Substances and DiseaseRegistry, U.S. Department of Health and Human Services.
ATSDR, 1990. Toxicological Profile for Benz[a]anthracene. Agency for Toxic Substances andDisease Registry, U.S. Department of Health and Human Services.
ATSDR, 1990. Toxicological Profile for Benzo[b]fluoranthene. Agency for Toxic Substances andDisease Registry, U.S. Department of Health and Human Services.
ATSDR, 1990. Toxicological Profile for Benzo[a]pyrene. Agency for Toxic Substances and DiseaseRegistry, U.S. Department of Health and Human Services.
ATSDR, 2000. Toxicological Profile for Manganese. Agency for Toxic Substances and DiseaseRegistry, U.S. Department of Health and Human Services.
Risk*Assistant for Windows, Software Version 1.1, Hampshire Research Institute, 1996.
Florida DEP Soil Target Cleanup Levels, Chapter 62-777, May 1999.
Florida DEP Groundwater Cleanup Target Levels, Chapter 62-302, May 1999.
Florida Department of Health Author
Shaun Anthony Crawford
Bureau of Environmental Epidemiology
Division of Environmental Health
Florida Department of Health Designated Reviewer
Bureau of Environmental Epidemiology
Division of Environmental Health
ATDSR Designated Reviewer
Technical Project Officer
Division of Health Assessment and Consultation
|Chemical Name||Highest Concentration||Screening Value|
A = ATSDR Screening Level
* = SCTL - Florida Department of Environmental Protection Soil Cleanup Target Level
|Chemical Name||Highest Concentration||Screening Value|
A = ATSDR Screening Level
* GCTL - Florida Department of Environmental Protection Groundwater Cleanup Target Level
J = Estimated Value
|Contaminant of Concern |
|Water - Ingestion (mg/kg/day) Dose|
Scenario Time-frame: Future
Land Use Conditions: Residential
Exposure Medium- Groundwater
Exposure Point- Ingestion of Drinking Water
Receptor Population- Residents
MRL - Minimum Risk Level for non-cancer illnesses
mg/kg/day = milligrams per kilogram per day
These doses were calculated using Risk Assistant Software (Hampshire Research Institute) and accepted values for groundwater consumption (EPA, 1991).
Doses were calculated using the following values:
acute = exposure is 1- 14 days
intermediate = exposure is 15-364 days
chronic = exposure is 365 and longer
Adult body weight = 70 kg
Adult water consumption = 2 liters
Water exposure is 350 events per year,
2 liters per day for 30 years
The Agency for Toxic Substances and Disease Registry (ATSDR) is a federal public healthagency 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 healthactions, and providing trusted health information to prevent harmful exposures and diseasesrelated to toxic substances. ATSDR is not a regulatory agency, unlike the U.S. EnvironmentalProtection Agency (EPA), which is the federal agency that develops and enforces environmentallaws to protect the environment and human health.
This glossary defines words used by ATSDR in communications with the public. It is not acomplete 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).
- The process of taking in. For a person or animal, absorption is the process of a substance 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].
- Adverse health effect:
- A change in body function or cell structure that might lead to disease or health problems.
- Surrounding (for example, ambient air).
- 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.
- 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.
- Decomposition or breakdown of a substance through the action of microorganisms (such as bacteria or fungi) or other natural physical processes (such as sunlight).
- 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.
- See Community Assistance Panel.
- Any one of a group of diseases that occurs when cells in the body become abnormal and grow or multiply out of control.
- Cancer risk:
- A theoretical risk of for getting cancer if exposed to a substance every day for 70 years (a lifetime exposure). The true risk might be lower.
- A substance that causes cancer.
- 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.
- [see Comprehensive Environmental Response, Compensation, and Liability Actof 1980]
- Occurring over a long time (more than 1 year) [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].
explore possible causes and contributing environmental factors.
- Community Assistance Panel (CAP):
- A group of people, from a community and from health and environmental agencies, who work with ATSDR to resolve issues and problems related to hazardous substances in the community. CAP members work with ATSDR to gather and review community health concerns, provide information on how people might have been or might now be exposed to hazardous substances, and inform ATSDR on ways to involve the community in its activities.
- Comparison value (CV):
- Calculated concentration of a substance in air, water, food, or soil that is unlikely to cause harmful (adverse) health effects in exposed people. The CV is used as a screening level during the public health assessment process. Substances found in amounts greater than their CVs might be selected for further evaluation in the public health assessment process.
- Completed exposure pathway:
- [see exposure pathway].
- Comprehensive Environmental Response, Compensation, and Liability Act of 1980(CERCLA):
- CERCLA, also known as Superfund, is the federal law that concerns the removal or cleanup of hazardous substances in the environment and at hazardous waste sites. ATSDR, which was created by CERCLA, is responsible for assessing health issues and supporting public health activities related to hazardous waste sites or other environmental releases of hazardous substances.
- The amount of a substance present in a certain amount of soil, water, air, food, blood, hair, urine, breath, or any other media.
- 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.
- Referring to the skin. For example, dermal absorption means passing through the skin.
- Dermal contact:
- Contact with (touching) the skin [see route of exposure].
- Detection limit:
- The lowest concentration of a chemical that can reliably be distinguished from a zeroconcentration.
- 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.
- United States Department of Defense.
- United States Department of Energy.
- Dose (for chemicals that are not radioactive):
- The amount of a substance to which a person is exposed over some time period. Dose is a measurement of exposure. Dose is often expressed as milligram (amount) per kilogram (ameasure of body weight) per day (a measure of time) when people eat or drink contaminatedwater, 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.
- United States Environmental Protection Agency.
- Contact with a substance by swallowing, breathing, or touching the skin or eyes. Exposure may be short-term [acute exposure], of intermediate duration, or long-term [chronic exposure].
- Exposure assessment :
- The process of finding out how people come into contact with a hazardous substance, how often and for how long they are in contact with the substance, and how much of the substance they are in contact with.
- Exposure-dose reconstruction:
- A method of estimating the amount of people's past exposure to hazardous substances. Computer and approximation methods are used when past information is limited, not available, or missing.
- Exposure investigation:
- The collection and analysis of site-specific information and biologic tests (when appropriate) to determine whether people have been exposed to hazardous substances.
- Exposure pathway:
- The route a substance takes from its source (where it began) to its end point (where it ends), and how people can come into contact with (or get exposed to) it. An exposure pathway has five parts: a source of contamination (such as an abandoned business); an environmental media and transport mechanism (such as movement through groundwater); a point of exposure (such as a private well); a route of exposure (eating, drinking, breathing, or touching), and a receptor population (people potentially or actually exposed). When all five parts are present, the exposure pathway is termed a completed exposure pathway.
- Exposure registry:
- A system of ongoing followup of people who have had documented environmental exposures.
- Feasibility study:
- A study by EPA to determine the best way to clean up environmental contamination. A number of factors are considered, including health risk, costs, and what methods will work well.
- Geographic information system (GIS):
- A mapping system that uses computers to collect, store, manipulate, analyze, and display data. For example, GIS can show the concentration of a contaminant within a community in relation to points of reference such as streets and homes.
- Water beneath the earth's surface in the spaces between soil particles and between rock surfaces [compare with surface water].
- Half-life (t½):
- The time it takes for half the original amount of a substance to disappear. In the environment, the half-life is the time it takes for half the original amount of a substance to disappear when it is changed to another chemical by bacteria, fungi, sunlight, or other chemical processes. In the human body, the half-life is the time it takes for half the original amount of the substance to disappear, either by being changed to another substance or by leaving the body. In the case of radioactive material, the half life is the amount of time necessary for one half the initial number of radioactive atoms to change or transform into another atom (that is normally not radioactive). After two half lives, 25% of the original number of radioactive atoms remain.
- 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 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 promotion:
- The process of enabling people to increase control over, and to improve, their health.
- 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 to such a decision is lacking.
- The act of swallowing something through eating, drinking, or mouthing objects. A hazardous 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 of exposure].
- Intermediate duration exposure:
- Contact with a substance that occurs for more than 14 days and less than a year [compare with acute exposure and chronic exposure].
- In vitro:
- In an artificial environment outside a living organism or body. For example, some toxicity testing is done on cell cultures or slices of tissue grown in the laboratory, rather than on a living animal [compare with in vivo].
- In vivo:
- Within a living organism or body. For example, some toxicity testing is done on whole animals, such as rats or mice [compare with in vitro].
- Lowest-observed-adverse-effect level (LOAEL):
- The lowest tested dose of a substance that has been reported to cause harmful (adverse) health effects in people or animals.
- Medical monitoring:
- A set of medical tests and physical exams specifically designed to evaluate whether anindividual's exposure could negatively affect that person's health.
- The conversion or breakdown of a substance from one form to another by a living organism.
- Any product of metabolism.
- Milligram per kilogram.
- Milligram per square centimeter (of a surface).
- Milligram per cubic meter; a measure of the concentration of a chemical in a known volume (a cubic 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 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].
- 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.
- No apparent public health hazard:
- A category used in ATSDR's public health assessments for sites where human exposure tocontaminated 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.
- [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.
- A craving to eat nonfood items, such as dirt, paint chips, and clay. Some children exhibit pica-related behavior.
- 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].
- 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.
- Parts per billion.
- Parts per million.
- Actions that reduce exposure or other risks, keep people from getting sick, or keep disease from getting worse.
- 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 availability session:
- An informal, drop-by meeting at which community members can meet one-on-one with ATSDRstaff members to discuss health and site-related concerns.
- 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 communityconcerns 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 byconditions 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 meeting:
- A public forum with community members for communication about a site.
- 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 of a substance that is unlikely to cause harm in humans.
- 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.
- RCRA Facility Assessment. An assessment required by RCRA to identify potential and 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 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]
- [see Superfund Amendments and Reauthorization Act]
- 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 environment.
- 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.
- 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.
- A chemical.
- Superfund Amendments and Reauthorization Act (SARA):
- In 1986, SARA amended 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].
- 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 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].
- 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 which, 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.
- The study of the harmful effects of substances on humans or animals.
- 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 asbenzene, toluene, methylene chloride, and methyl chloroform.
Other glossaries and dictionaries:
Environmental Protection Agency http://www.epa.gov/OCEPAterms/
National Center for Environmental Health (CDC) http://www.cdc.gov/nceh/dls/report/glossary.htm
National Library of Medicine http://www.nlm.nih.gov/medlineplus/mplusdictionary.html
The Florida Department of Health, Bureau of Environmental Epidemiology prepared this Health Consultation under a cooperative agreement with the Agency for Toxic Substances and Disease Registry. It followed approved methodology and procedures existing at the time it began.
Technical Project Officer,
SPS, SSAB, DHAC
The Division of Health Assessment and Consultation, ATSDR, has reviewed this healthconsultation, and concurs with its findings.
SPS, SSAB, DHAC,