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Review of Iron Oxide And Particulate Data



Staff from the Waccamaw District office of the South Carolina Department of Health andEnvironmental Control (SCDHEC) asked for a review of monitoring data collected in Georgetown,Georgetown County, South Carolina. These data were collected as part of the Georgetown AirQuality Study (GAQS) started in 2000. This health consultation will address the potential healtheffects of the iron-oxide (red staining) and other particulate matter observed (specifically PM 2.5 andPM 10) near the Georgetown Steel Corporation. The issue of the potential health effects of the iron-oxide will be included as part of the Georgetown Air Quality Study. Even though the iron-oxide isalso particulate matter, it will be discussed separately from the discussion of the PM 2.5 and PM 10particulate matter. The Office of Environmental Community Health prepared this healthconsultation under cooperative agreement with the Agency for Toxic Substances and DiseaseRegistry (ATSDR).

In the early 1970's, SCDHEC (then referred to as the South Carolina Pollution Control Authority)began investigating complaints of staining on structures in downtown Georgetown, South Carolina. The initial complaints coincided with the startup of two steel production facilities in the area,Georgetown Steel Company (GSC) and Georgetown Ferreduction (later purchased by GSC). Bothfacilities were built at the corner of Fraser and Front Streets, less than a block from downtownbusinesses and homes. Soon after the companies opened, residents within several blocks of thefacilities reported problems with staining, specifically red staining, on the exterior surfaces of homes,businesses, cars, and boats. The complainants believed that the staining resembled emissions generated by the steel facilities. Several times during the 1970's, 1980's, and 1990's, SCDHEC investigated complaints, documented air permit violations, and brought enforcement actions againstthe company. The company did take steps through the years to reduce and control particulate matteremissions at the facility. Some of these improvements included upgrading ductwork for bettercollection of dust, installation of baghouses to increase the control of emissions from various stagesin the production, paving plant roads to reduce fugitive dust emissions, and closing roof louvers andopenings in the melt shop. Red staining continues to be a problem in the downtown Georgetownarea (SCDHEC, 2003).

Through the years, the Georgetown community has expressed concerns about possible healthproblems associated with the material that was causing the red stain. In a 1996 study, SCDHEC'sDivision of Air Quality Analysis identified the stain as goethite. Goethite is an oxidation productof iron (SCDHEC, 2003).

In 1996, SCDHEC's Division of Air Quality Analysis (DAQA) and Waccamaw EQC District airstaff began a special air quality study (Project Plan and Final Report for "What Changed the Colorof My Boat?"). Three sampling monitors were placed around the city of Georgetown to collectsamples, specifically the red stain. SCDHEC's Division of Air Quality Analysis identified the stainas goethite. Goethite is an oxidation product of iron (SCDHEC, 2003). The 1996 report concludedthat a primary contributor to the staining of the fiber glass plates was Georgetown Steel Corporation. The study raised the question as to whether other mechanisms and/or components, such as otherindustrial pollutants, might be involved with the formation of the red stain.

SCDHEC staff contacted the Air Pollution Control Departments in Florida and Pittsburgh todetermine if the red stain is simply a byproduct of steel production. The red staining problem did notoccur around steel mills in either of these areas. During the same time period, SCDHEC conductedair quality inspections at several major facilities in the Georgetown area. Only minor violations werenoted during these inspections.

Since 1996, Waccamaw District air staff have increased air quality surveillance in Georgetown byconducting unannounced visits to the area at different times of the day and night. Filters collectedfrom DAQA's particulate samplers set up in the Georgetown area have been analyzed to determinetheir content. Special air sampling conducted during the shutdown of several area plants has alsobeen performed. The results of these efforts proved to be informative, but did not provide enoughinformation to determine what stage or stages of the manufacturing process emitted the particlesnecessary for the stain to result and if other pollutants were involved in the formation of the redstaining (SCDHEC, 2003). To attempt to resolve this question, SCDHEC began a Bi-State Studywith Alabama in September 2000.

SCDHEC attempted to determine the extent and magnitude of the red staining and to determine ifother components or mechanisms played a significant role in the development of the stain. The partof the study to determine extent of staining was inconclusive. Apparent staining showed a widevariability and no study area could be defined (SCDHEC, 2003). To determine whether or not otherfactors contribute to the staining problem, SCDHEC and the Alabama Department of EnvironmentalManagement completed a joint state study. The intent of the Bi-State Study was to compare the redstain observed in Georgetown to the red stain observed around the DRI facility located in Mobile,Alabama. The main objective of this study was to determine if goethite (red staining) stainingresulted from emissions generated at a DRI facility without the influence of other industrialcomponents present in Georgetown. It was determined that the goethite from the Alabama monitorswas found to be optically similar to the goethite found on the Georgetown monitor. Thesesimilarities indicated that some element of the DRI process at GSC contributed significantly to thered staining found in the Georgetown area (SCDHEC, 2003).

Currently, there are four monitoring stations in the Georgetown area. A summary table of datacollected during the last five years is presented below. A more complete listing of the data arepresented in Appendix A. The iron is measured as elemental iron on the total suspended particulatefilters at each of the locations. Iron is reported as micrograms per cubic meter or g/m3.

Georgetown Area
Iron Concentrations in Particulate Filters
Site NameRange Concentration (g/m3) Mean Concentration(g/m3)
Howard High School



Georgetown CMS



Maryville Power Sub Station






The station at Winyah is between Dozier Street and Cleland Street. The station was placed tomeasure the greatest impact of emissions from Georgetown's primary industries. The Maryville SubStation is a Santee Cooper electrical substation at the intersection of Power Avenue and Ward Street.The Maryville Sub Station serves as a local background monitoring station. Georgetown CMS, theGeorgetown Continuous Monitoring station, is south of the Georgetown Steel Corporation. TheHoward High School station is at Howard Adult & Community Education Center located at 500 S.Kaminski Street.

The only standards available to use for comparison are those that have been developed for use in occupational settings. Occupational settings typically involve much higher exposures and exposureto many materials. The American Conference of Government Industrial Hygienists (ACGIH)recommend an exposure limit of 5,000 g/m3 time weighted average measured as iron. The UnitedStates Occupational Safety and Health Administration (OSHA) limits permissible exposure to10,000 g/m3 measured as total iron particulates.

Particulate matter is a complex mixture of small particles and liquid droplets. Fine particles can beemitted directly from sources such as diesel engines, wood burning activities, and other industrialand commercial combustion processes (U.S.EPA, 2003). The size of the particulate is very importantto understanding the likelihood of exposure. Generally fine particulate matter is more likely to beinhaled into the lungs. Exposure to high levels of fine particulate matter has the potential to causeadverse health effects. Asthmatics, senior citizens, and people with respiratory disease and heartdisease can be particularly sensitive to the effects of particulates.

Particulate data (PM 2.5) has been collected in the Georgetown area (Winyah station) since 1999.The sampler runs every three days for 24 hours, midnight to midnight. There are no continuous PM2.5 monitors in Georgetown. The annual average for the Winyah station has only slightly exceededthe national annual standard for PM 2.5 once (15.5 g/m3) since SCDHEC started measuring PM2.5. The national standard is 15 g/m3 for an annual average. The 24-hour maximum standard (65g/m3) has not been exceeded at the Winyah station. The levels of PM 2.5 for the Winyah stationare similar to other parts of the state with annual averages across the state ranging from 11 to 15 g/m3.

The PM 10 data are monitored at the Winyah station as well as at Howard High. The samplers atthese locations run samples every six days. Data have been collected since 1997 (1991 atGeorgetown CMS). The annual average for the Georgetown area monitoring stations range from23 g/m3 to 30 g/m3. The level of PM 10 measured in Georgetown are consistently below the national annual standard of 50 g/m3. The level of PM 10 particulate data for the Georgetown areaare consistent with the rest of South Carolina with state-wide annual averages ranging from 20 to24 g/m3. The maximum level of PM 10 in the Georgetown area never exceeded the U.S.EPA 24-hour standard (150 g/m3).


SCDHEC has been monitoring the iron content of the total suspended particulate (TSP) filters since1996. The American Conference of Government Industrial Hygienists (ACGIH) recommend anexposure limit of 5,000 µg/m3 time weighted average measured as iron. At this level, exposure isunlikely to result in the accumulation of particles in the lung and x-ray changes. The United StatesOccupational Safety and Health Administration (OSHA) limits permissible exposure to 10,000µg/m3 measured as total particulates, to prevent the iron oxide accumulation in the lungs. The levelsof iron found in particulate matter in Georgetown are orders of magnitude less than the occupationalexposure limits. The maximum level of iron in the last five years was 73 µg/m3 found at the Winyahmonitoring station. The average iron concentrations over the last five years is less than 5.0 µg/m3, which is also much lower then the available standard. Iron oxide is generally not considered tobe a toxic material (Boyd and Shanas, 1963; Boyd and Shanas, 1967).

Red staining is a common by-product of the DRI process. The movement, stockpiling, andprocessing of iron ore fines creates iron dust. Many occupations involve exposure to iron oxide andiron including iron ore miners, miners, welders, caulker/burners, metal dressers, oxyacetylenecutters, pigment workers, turners, grinders, fettlers, steel and iron rolling mill workers and silverpolishers. Welders particularly, can be exposed to high levels of iron oxide dust and fumes. Typicaloccupation exposures are around 3,000-50,000 µg/m3. The accumulation of iron oxide in the lungscan be associated with the development of a condition called siderosis. Siderosis is considered abenign condition that resolves over a number of years once exposure stops. Siderosis is generallyconsidered a condition of overload, where the exposure to the dust is in excess of the lungs abilityto clear the particles (Flahive, 2001; Lay et al. 1999).

Most, if not all, of the information about adverse health effects of exposure to iron is obtained fromworkplace studies and a few studies with human volunteers. Workplace exposures likely involvesimultaneous inhalation exposures to other materials. In general, iron-oxide is not very toxic andis more of an irritant than a toxic material. In workers, who are exposed to much higher levels ofiron-oxide than the general public, siderosis may contribute to reduced lung function and patchyfibrosis. Over time the iron-oxide dust is slowly cleared from the lungs (Flahive, 2001).

Based on the available iron data generated from the TSP filters over the past few years, it does notappear as though the iron concentrations in the Georgetown area are at levels that would pose risksto area residents. The concentrations are far below current health based (occupational) standards. Although inhalation of iron has been linked with a condition that can decrease lung function, itseems to only be associated with workplace exposures and not with other types of exposures (Layet al., 2001). Area residents would not develop this condition even if they were exposed to theaverage level of iron measured in the community.

The levels of particulates (PM 2.5 and PM 10) in the Georgetown area are low and are consistentwith the rest of the State of South Carolina. At no time in the last seven years of monitoring, haveparticulates exceeded the 24-hour maximum standard for either PM 2.5 or PM 10. Only once did PM 2.5 exceed the annual average standard level and then it was only slightly exceeded. Theinhalation of fine particulate matter has been associated with lung function decreases, airwayinflammation, and respiratory symptoms. Senior citizens, children, asthmatics, and people withongoing lung or heart problems can be particularly sensitive to the effects of inhaled particulates. Particulate levels in Georgetown are low and there is no reason for the general population living inGeorgetown area to experience adverse health effects from inhaling particulates.


SCDHEC's evaluation contained within this document considered children as a susceptiblesubpopulation. There is no information to indicate whether or not children are more or lesssusceptible to exposure to iron-oxide. However, the levels of iron measured in air aroundGeorgetown are an order of magnitude less than the federal standard. Children can be more sensitiveto the effects of particulates. The level of particulates in the Georgetown area are low and there isno reason to expect that area children are exposed to levels of iron-oxide or other particulates that would pose a risk to their health.


It is unlikely that residents living in the area with the red staining problem are exposed to levels ofiron or particulates associated with the development of health effects. The levels of iron monitoredover a four year period are much lower than the established standards for iron. Particulate levels inGeorgetown are low and there is no reason for the general population living in Georgetown area toexperience adverse health effects from inhaling particulates.

ATSDR classifies sites as to their public health hazard category. Under ATSDR's classificationsystem, the inhalation of red staining or iron-oxide and other particulates in residential areas ofGeorgetown is not expected to result in adverse health effects and is categorized as a no public health hazard.


No further public health actions are warranted with regard to the iron-oxide or red staining or other particulate matter.


The results of this first health consultation will be provided to the public as part of the presentation of the Summary of the Georgetown Air Quality Study.


Boyd, Eldon M. and Shanas, M.N. 1963. The Acute Oral Toxicity of Reduced Iron. J. Canad. Med. Assoc. Vol. 89, 171-175.

Boyd, Eldon M. and Shanas, M.N. 1967. Studies on the Low Toxicity of Reduced Iron, B. P. 1932. J. Canad. Med. Assoc. Vol. 96, 1141-1146.

Flahive, Dr. Martyn. Nov. 2001. Summary Paper for the Investigation of the Health Effects of Iron, Iron Oxide and Iron Ore Dusts. Discussion Paper and Literature Review.

Lay, John C., Zeman, Kirby L., Ghie, Andrew J., Bennett, William D. 2001. Effects of Inhaled Iron Oxide Particles on Alvelolar Epithelial Permeability in Normal Subjects. Inhalation Toxicology, 13:1065-1078.

Lay, John C., Williams, D., Bennett, Ghio, Andrew J., Bromberg, Philip A., Costa, Daniel L., Chong, Kim S., Koren, Hillel S., Devlin Robert B. 1999. Cellular and Biochemical Response of the Human Lung after Intrapulmonary Instillation of Ferric Oxide Particles. Am. J. Respir. Cell Mol. Biol. Vol. 20, 631-642.

South Carolina Department of Health and Environmental Control. 2003. Georgetown Air Quality Study. Summary of Findings.


Tracy Shelley, MS
Program Manager
Office of Environmental Community and Environmental Health
South Carolina Department of Health and Environmental Control

ATSDR Technical Reviewer

Debra Gable
Technical Project Officer
Division of Health Assessment and Consultation


Station Name Site ID Total # of years Minimum Maximum Average Mean
GEORGETOWN CMS 45-043-0006 5 0.050 154.24 2.955
GEORGETOWN COUNTY HEALTH DEPT 45-043-0001 1 0.360 13.81 3.030
HOWARD HIGH SCHOOL 45-043-0002 5 0.050 59.33 1.450
MARYVILLE 45-043-0007 5 0.010 14.63 0.325
WINYAH 45-043-0009 5 0.070 197.84 3.212


For All Sites     0.010 197.84 2.035

  Annual Arith Mean Min Sample Value
1996 1997 1998 1999 2000 1996 1997 1998 1999 2000
GEORGETOWN CMS 5.477 2.725 2.283 1.728 2.560 0.73 0.18 0.11 0.05 0.37
GEORGETOWN COUNTY HEALTH DEPT 3.030         0.36        
HOWARD HIGH SCHOOL 2.123 1.496 1.261 1.414 0.954 0.35 0.10 0.10 0.05 0.07
MARYVILLE 0.518 0.290 0.277 0.237 0.301 0.06 0.01 0.05 0.06 0.05
WINYAH 6.233 2.480 1.963 2.392 2.992 0.35 0.18 0.07 0.21 0.14

  1996 1997 1998 1999 2000
Max Sample Value Max Sample Value Max Sample Value Max Sample Value Max Sample Value
45-043-0006 154.24 63.71 55.16 43.16 73.16
45-043-0001 13.81        
45-043-0002 59.33 43.27 38.16 46.43 31.91
45-043-0007 14.63 8.06 6.80 5.22 8.16
45-043-0009 197.84 79.66 58.76 79.71 96.77


The Agency for Toxic Substances and Disease Registry (ATSDR) is a federal public health agencywith headquarters in Atlanta, Georgia, and 10 regional offices in the United States. ATSDR'smission is to serve the public by using the best science, taking responsive public health actions, andproviding trusted health information to prevent harmful exposures and diseases related to toxicsubstances. ATSDR is not a regulatory agency, unlike the U.S. Environmental Protection Agency(EPA), which is the federal agency that develops and enforces environmental laws to protect theenvironment 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, callATSDR'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 gettinginto 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 withintermediate duration exposure and chronic exposure].

Additive effect:
A biologic response to exposure to multiple substances that equals the sum of responses of all theindividual substances added together [compare with antagonistic effect and synergistic effect].

Adverse health effect:
A change in body function or cell structure that might lead to disease or health problems.

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, orblood) is tested in a laboratory. For example, if the analyte is mercury, the laboratory test willdetermine the amount of mercury in the sample.

Analytic epidemiologic study:
A study that evaluates the association between exposure to hazardous substances and disease bytesting scientific hypotheses.

Antagonistic effect:
A biologic response to exposure to multiple substances that is less than would be expected if the known effects of the individual substances were added together [compare with additive effectand synergistic effect].

Background level:
An average or expected amount of a substance or radioactive material in a specific environment, ortypical amounts of substances that occur naturally in an environment.

Decomposition or breakdown of a substance through the action of microorganisms (such as bacteriaor fungi) or other natural physical processes (such as sunlight).

Biologic indicators of exposure study:
A study that uses (a) biomedical testing or (b) the measurement of a substance [an analyte], itsmetabolite, or another marker of exposure in human body fluids or tissues to confirm humanexposure to a hazardous substance [also see exposure investigation].

Biologic monitoring :
Measuring hazardous substances in biologic materials (such as blood, hair, urine, or breath) todetermine whether exposure has occurred. A blood test for lead is an example of biologicmonitoring.

Biologic uptake:
The transfer of substances from the environment to plants, animals, and humans.

Biomedical testing:
Testing of persons to find out whether a change in a body function might have occurred because ofexposure to a hazardous substance.

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 arestored 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 ormultiply out of control.

Cancer risk:
A theoretical risk of for getting cancer if exposed to a substance every day for 70 years (a lifetimeexposure). 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) with people whodo not have the disease or condition (controls). Exposures that are more common among the casesmay be considered as possible risk factors for the disease.

CAS registry number:
A unique number assigned to a substance or mixture by the American Chemical Society AbstractsService.

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 Act of1980]

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 acuteexposure and intermediate duration exposure].

Cluster investigation:
A review of an unusual number, real or perceived, of health events (for example, reports of cancer)grouped together in time and location. Cluster investigations are designed to confirm case reports;determine whether they represent an unusual disease occurrence; and, if possible, explore possiblecauses and contributing environmental factors.

Community Assistance Panel (CAP):
A group of people, from a community and from health and environmental agencies, who work withATSDR to resolve issues and problems related to hazardous substances in the community. CAPmembers work with ATSDR to gather and review community health concerns, provide informationon how people might have been or might now be exposed to hazardous substances, and informATSDR 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 publichealth assessment process. Substances found in amounts greater than their CVs might be selectedfor 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 ofhazardous substances in the environment and at hazardous waste sites. ATSDR, which was createdby CERCLA, is responsible for assessing health issues and supporting public health activities relatedto 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 levelsthat might cause harmful (adverse) health effects.

Delayed health effect:
A disease or injury that happens as a result of exposures that might have occurred in the past.

Referring to the skin. For example, dermal absorption means passing through the skin.

Dermal contact:
Contact with (touching) the skin [see route of exposure].

Descriptive epidemiology:
The study of the amount and distribution of a disease in a specified population by person, place, and time.

Detection limit:
The lowest concentration of a chemical that can reliably be distinguished from a 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 definedpopulation.

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 ameasurement of exposure. Dose is often expressed as milligram (amount) per kilogram (a measureof body weight) per day (a measure of time) when people eat or drink contaminated water, food, orsoil. In general, the greater the dose, the greater the likelihood of an effect. An "exposure dose" ishow much of a substance is encountered in the environment. An "absorbed dose" is the amount ofa 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 changesin body function or health (response).

Environmental media:
Soil, water, air, biota (plants and animals), or any other parts of the environment that can containcontaminants.

Environmental media and transport mechanism:
Environmental media include water, air, soil, and biota (plants and animals). Transport mechanismsmove contaminants from the source to points where human exposure can occur. The environmentalmedia and transport mechanism is the second part of an exposure pathway.

United States Environmental Protection Agency.

Epidemiologic surveillance:
The ongoing, systematic collection, analysis, and interpretation of health data. This activity alsoinvolves timely dissemination of the data and use for public health programs.

The study of the distribution and determinants of disease or health status in a population; the studyof the occurrence and causes of health effects in humans.

Contact with a substance by swallowing, breathing, or touching the skin or eyes. Exposure may beshort-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 andfor how long they are in contact with the substance, and how much of the substance they are incontact with.

Exposure-dose reconstruction:
A method of estimating the amount of people's past exposure to hazardous substances. Computerand 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) todetermine 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 howpeople can come into contact with (or get exposed to) it. An exposure pathway has five parts: asource of contamination (such as an abandoned business); an environmental media and transportmechanism (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 (peoplepotentially or actually exposed). When all five parts are present, the exposure pathway is termed acompleted 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 offactors 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. Forexample, GIS can show the concentration of a contaminant within a community in relation to pointsof 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 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, thehalf-life is the time it takes for half the original amount of a substance to disappear when it ischanged to another chemical by bacteria, fungi, sunlight, or other chemical processes. In the humanbody, 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 radioactivematerial, the half life is the amount of time necessary for one half the initial number of radioactiveatoms to change or transform into another atom (that is normally not radioactive). After two halflives, 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 data collection,retrieval, and analysis of site-specific information on hazardous substances, community healthconcerns, 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 questionor request for information about a potential environmental hazard. Health consultations are focusedon a specific exposure issue. Health consultations are therefore more limited than a public healthassessment, which reviews the exposure potential of each pathway and chemical [compare withpublic health assessment].

Health education:
Programs designed with a community to help it know about health risks and how to reduce theserisks.

Health investigation:
The collection and evaluation of information about the health of community residents. Thisinformation is used to describe or count the occurrence of a disease, symptom, or clinical measureand to estimate the possible association between the occurrence and exposure to hazardoussubstances.

Health promotion:
The process of enabling people to increase control over, and to improve, their health.

Health statistics review:
The analysis of existing health information (i.e., from death certificates, birth defects registries, andcancer registries) to determine if there is excess disease in a specific population, geographic area,and time period. A health statistics review is a descriptive epidemiologic study.

Indeterminate public health hazard:
The category used in ATSDR's public health assessment documents when a professional judgmentabout the level of health hazard cannot be made because information critical to such a decision islacking.

The number of new cases of disease in a defined population over a specific time period [contrastwith prevalence].

The act of swallowing something through eating, drinking, or mouthing objects. A hazardoussubstance 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 testingis 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 effectsin people or animals.

Medical monitoring:
A set of medical tests and physical exams specifically designed to evaluate whether an individual'sexposure 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 cubicmeter) 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 thatsubstance is unlikely to pose a measurable risk of harmful (adverse), noncancerous effects. MRLsare 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].

State of being ill or diseased. Morbidity is the occurrence of a disease or condition that alters healthand quality of life.

Death. Usually the cause (a specific disease, condition, or 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 Priorities List orNPL):
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 thefuture, 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) healtheffects on people or animals.

No public health hazard:
A category used in ATSDR's public health assessment documents for sites where people have neverand 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 howthe chemical gets into the body, where it goes in the body, how it is changed by the body, and howit 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. Plumescan be described by the volume of air or water they occupy and the direction they move. Forexample, a plume can be a column of smoke from a chimney or a substance moving withgroundwater.

Point of exposure:
The place where someone can come into contact with a substance present in the environment [seeexposure pathway].

A group or number of people living within a specified area or sharing similar characteristics (suchas occupation or age).

Potentially responsible party (PRP):
A company, government, or person legally responsible for cleaning up the pollution at a hazardouswaste site under Superfund. There may be more than one PRP for a particular site.

Parts per billion.

Parts per million.

Prevalence :
The number of existing disease cases in a defined population during a specific time period [contrastwith incidence].

Prevalence survey:
The measure of the current level of disease(s) or symptoms and exposures through a questionnairethat collects self-reported information from a defined population.

Actions that reduce exposure or other risks, keep people from getting sick, or keep disease fromgetting worse.

Public comment period:
An opportunity for the public to comment on agency findings or proposed activities contained indraft reports or documents. The public comment period is a limited time period during whichcomments 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 hazardoussubstances poses an immediate threat to human health. The advisory includes recommendedmeasures 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 intocontact with those substances. The PHA also lists actions that need to be taken to protect publichealth [compare with health consultation].

Public health hazard:
A category used in ATSDR's public health assessments for sites that pose a public health hazardbecause of long-term exposures (greater than 1 year) to sufficiently high levels of hazardous substances or radionuclides that could result in harmful health effects.

Public health hazard categories:
Public health hazard categories are statements about whether people could be harmed by conditionspresent at the site in the past, present, or future. One or more hazard categories might be appropriatefor each site. The five public health hazard categories are no public health hazard, no apparentpublic health hazard, indeterminate public health hazard, public health hazard, and urgentpublic health hazard.

Public health statement:
The first chapter of an ATSDR toxicological profile. The public health statement is a summarywritten in words that are easy to understand. The public health statement explains how people mightbe 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.

An unstable or radioactive isotope (form) of an element that can change into another element bygiving 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 of a substancethat is unlikely to cause harm in humans.

Registry :
A systematic collection of information on persons exposed to a specific substance or having specificdiseases [see exposure registry and disease registry].

Remedial Investigation:
The CERCLA process of determining the type and extent of hazardous material contamination ata 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 actualreleases 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 experiencedisease 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 arebreathing [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 beingstudied. For example, in a study of people the sample is a number of people chosen from a largerpopulation [see population]. An environmental sample (for example, a small amount of soil orwater) 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 mineralspirits).

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 offactors 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 dataor information. Statistics are used to determine whether differences between study groups aremeaningful.

A chemical.

Substance-specific applied research:
A program of research designed to fill important data needs for specific hazardous substancesidentified in ATSDR's toxicological profiles. Filling these data needs would allow more accurateassessment of human risks from specific substances contaminating the environment. This researchmight include human studies or laboratory experiments to determine health effects resulting fromexposure to a given hazardous substance.

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 athazardous 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 withgroundwater].

[see epidemiologic surveillance]

A systematic collection of information or data. A survey can be conducted to collect informationfrom a group of people or from the environment. Surveys of a group of people can be conducted bytelephone, by mail, or in person. Some surveys are done by interviewing a group of people [seeprevalence survey].

Synergistic effect:
A biologic response to multiple substances where one substance worsens the effect of anothersubstance. The combined effect of the substances acting together is greater than the sum of theeffects of the substances acting by themselves [see additive effect and antagonistic effect].

Teratogen :
A substance that causes defects in development between conception and birth. A teratogen is asubstance that causes a structural or functional birth defect.

Toxic agent:
Chemical or physical (for example, radiation, heat, cold, microwaves) agents which, under certaincircumstances of exposure, can cause harmful effects to living organisms.

Toxicological profile:
An ATSDR document that examines, summarizes, and interprets information about a hazardoussubstance to determine harmful levels of exposure and associated health effects. A toxicologicalprofile also identifies significant gaps in knowledge on the substance and describes areas wherefurther 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 uncontrolled andprogressive. Tumors perform no useful body function. Tumors can be either benign (not cancer)or malignant (cancer).

Uncertainty factor:
Mathematical adjustments for reasons of safety when knowledge is incomplete. For example, factorsused in the calculation of doses that are not harmful (adverse) to people. These factors are appliedto 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 forvariations in people's sensitivity, for differences between animals and humans, and for differencesbetween a LOAEL and a NOAEL. Scientists use uncertainty factors when they have some, but notall, the information 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-term exposures (lessthan 1 year) to hazardous substances or conditions could result in harmful health effects that requirerapid intervention.

Volatile organic compounds (VOCs):
Organic compounds that evaporate readily into the air. VOCs include substances such as benzene,toluene, methylene chloride, and methyl chloroform.

Other glossaries and dictionaries:

Environmental Protection Agency:
National Center for Environmental Health (CDC):
National Library of Medicine:


The South Carolina Department of Health and Environmental Control's Office of EnvironmentalCommunity Health prepared this Georgetown County health consultation under a cooperativeagreement with the Agency for Toxic Substances and Disease Registry. It is in accordance with approved methodology and procedures existing at the time the health consultation was begun.

Debra Gable
Technical Project Officer
Superfund Site Assessment Branch (SSAB)
Division of Health Assessment and Consultation (DHAC)

The Division of Health Assessment and Consultation, ATSDR, has reviewed this health consultation, and concurs with its findings.

Roberta Erlwein
Section Chief,

Table of Contents The U.S. Government's Official Web PortalDepartment of Health and Human Services
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