PUBLIC HEALTH ASSESSMENT
RUBBERTOWN INDUSTRIAL AREA
JEFFERSON COUNTY, KENTUCKY
|Compound||Maximum Concentration West End||Comparison Value (µg/m3)|
|Vinyl Chloride||5 ,930||15,158||77||i-EMEG|
ppb = parts per billion
µg/m3 = micrograms per cubic meter
CREG = Cancer Risk Evaluation Guide
a-EMEG = acute Environmental Media Evaluation Guide
c-EMEG = chronic Environmental Media Evaluation Guide
i-EMEG = intermediate Environmental Media Evaluation Guide
1 Comparison value is for 1,3-Butadiene
2 Comparison value is for 1,2-Dichloroethane
Bolded values indicate chemicals for which the maximum concentration detected exceeded comparison values. For information on the comparison values used in this table, please refer to Appendix D and Appendix E.
|Compound||Number of detections (out of 37 samples)||Maximum Concentration (µg/m3)||Comparison Value (µg/m3) |
µg/m3 = micrograms per cubic meter
CREG = Cancer Risk Evaluation Guide
a-EMEG = acute Environmental Media Guide
c-EMEG = chronic Environmental Media Guide
i-EMEG = intermediate Environmental Media Guide
EPA-III = U.S. Environmental Protection Agency Region III Risk-Based Concentration
1The carcinogenicity of tetrachloroethylene and trichloroethylene is currently being reviewed by health officials.
Bolded values indicate chemicals for which the maximum concentration detected exceeded comparison values. For information on the comparison values used in this table, please refer to Appendix D and Appendix E.
|Compound||Maximum Concentration (ppm) |
|Comparison Value (ppm)|
|Arsenic ||26.7||20||Chronic EMEG (child)|
|200||Chronic EMEG (adult)|
|Cadmium ||4.2||40||Chronic EMEG (child)|
|500||Chronic EMEG (adult)|
|Lead||851.8||400||EPA screening value for residential surface soil|
ppm = parts per million
EMEG = Environmental Media Evaluation Guide
For information on the comparison values used in this table, please refer to Appendix D and Appendix E.
|PATHWAY NAME||EXPOSURE PATHWAY ELEMENTS||TIME|
|SOURCE||MEDIA||POINT OF EXPOSURE||ROUTE OF EXPOSURE||EXPOSED POPULATION|
|POTENTIAL EXPOSURE PATHWAYS|
|AIR||Rubbertown industrial facilities||air||on-site; |
|inhalation||Rubbertown Workers and West Louisville residents||past present future|
|BIOTA (locally caught fish)||Unknown||carp |
|Chickasaw Park Lake||ingestion||West Louisville residents||past|
|SURFACE SOIL||RCRA sites; |
|surface soil||residential areas||incidental ingestion |
|West Louisville residents (West End)||past present future|
|ELIMINATED EXPOSURE PATHWAYS|
|GROUNDWATER||Rubbertown industrial facilities||groundwater||none||none||none||present|
|SURFACE WATER||Unknown||surface water||none||none||none||present|
Health Implications of Exposure to Air Contaminants
During the 1956-1957 Special Air Pollution Study, acrylonitrile, benzene, butadiene (isomer unspecified), xylene, chloroform, dichloroethane (isomer unspecified) and vinyl chloride were detected above comparison values. Acrylonitrile, benzene, butadiene and vinyl chloride were detected at particularly high levels. Several of these compounds were later detected above comparison values in either the 1980-1997 Kentucky Air Pollution District sampling or the 1988 Urban Air Toxic Monitoring Program. These include: benzene; 1,3-butadiene; and 1,2-dichloroethane. Chloroform was also detected above comparison values, but in only one sample.
In selecting chemicals of concern, ATSDR focused on those chemicals that were elevated in both the 1950s study, and in the later 1980s studies (benzene, butadiene, and dichloroethane). However, ATSDR also selected acrylonitrile and vinyl chloride for further evaluation because both chemicals were widely used in rubber production, were present at fairly high levels in the 1950s' air, and are potential (or known) carcinogens.
Ozone was selected as a chemical of concern because Louisville has been a "non-attainment" area for ozone since 1980.
During the 1956 air study, acrylonitrile was detected at 335 parts per billion (ppb) which is above conservative ATSDR comparison values. ATSDR reviewed available scientific information on health effects from breathing air containing acrylonitrile. Much of this information indicates that the 1956 air concentration is much lower than levels at which adverse health effects were shown to occur. Studies show that following brief exposure to 16,000 ppb (a level much higher than the 335 ppb reported in 1956), workers developed headaches and nausea. Workers repeatedly exposed to higher levels may have had a greater likelihood of developing lung cancer, although the link between cancer and acrylonitrile has not been clearly established (ATSDR, 1990). This information, therefore, suggests that exposure to levels reported in 1956 would not be expected to pose a health concern. Because no long-term or more recent sampling data are available for this compound, it is not possible to say with certainty whether West Louisville residents have been exposed over a long period of time to harmful levels of acrylonitrile.
In 1988, benzene was detected in Louisville air in 25 of 37 samples. The maximum concentration detected was 3.09 ppb, which is well within background levels for the US (2.8 to 20 ppb) (ATSDR, 1997a). Most often, benzene in ambient air is associated with industrial emissions, tobacco smoke, gas stations, and motor vehicle exhaust. Rubber products manufacturing, petrochemicals and petroleum refining are industries that typically emit benzene to the environment. In 1956, benzene was detected in West End air at much higher levels (144 ppb) than recorded in the 1988 study.
Most of what we know about human health effects from breathing air containing benzene is from studies of workers employed in industries that produce or use benzene. Workers exposed for short periods of time to levels ranging from 700-3,000 parts per million (ppm) of benzene experienced drowsiness, headaches, and rapid heart rate, but in most cases these symptoms resolved when exposure stopped. Workers who breathed air containing even higher concentrations of benzene for long periods developed immune system problems or cancer (e.g., acute myeloid leukemia) (ATSDR, 1997a).
Health effects appear to be associated with exposure to air levels of benzene far greater than those recorded in Louisville during the 1956 and 1988 studies. In fact, based on the levels of benzene detected in the air in 1988, Louisville residents were exposed to benzene at that time at approximately 8,000 times less than the lowest concentration associated with noncarcinogenic effects (approximately 25 ppm), and 3,000 times less than the concentration that is more clearly associated with carcinogenic effects (10 ppm). The 1956 data indicate that some exposure was occurring at an order of magnitude (10 times) less that the lowest concentration associated with carcinogenic effects (ATSDR, 1997a).
1,3 Butadiene was detected in Louisville air in 1988 at concentrations up to 0.89 ppb. It was detected in roughly one fifth of the samples (7 of 37). The average concentration in suburban and urban environments is 0.3 ppb. 1,3-Butadiene is a colorless gas that is widely found in urban air from various sources, including rubber and plastic production, auto exhaust, gasoline stations, and cigarette smoke. In 1956, butadiene was detected at 1,830 ppb. (1,3-butadiene is one isomer, or form, of butadiene. It is not known which particular isomer of the chemical was detected in 1956.)
No studies have shown a link between environmental exposures of 1,3-butadiene and health effects, including cancer. Detected levels of 1,3-butadiene are several thousand times lower than levels shown to cause eye, nose, and throat irritation, and central nervous system effects. Workers exposed to 1,3-butadiene for long periods had an increased incidence of heart disease, lung disease, and hemato-lymphopoietic cancer, but not other cancers (Matanoski, 1989; Downs, 1987). It is not known what specific level of exposure to 1,3-butadiene may cause cancer in humans because exposure levels were not measured in these studies. Field studies not associated with cancer studies have detected 1,3-butadiene ranging from 0.006-174 ppm in the air of plants utilizing the chemical (ATSDR, 1992). Without better information on the levels associated with cancer in humans, ATSDR cannot fully evaluate the long-term health significance of the reported 1,3-butadiene air concentration.
1,2-Dichloroethane was detected in almost half of the 1988 samples in air at a maximum level that exceeds ATSDR comparison values. These levels, however, are comparable to background levels detected in national urban air studies (0.1-1.5 ppb) (ATSDR, 1994). Dichloroethane was not detected in elevated concentrations in the 1956 study; however, this study did not specify which form, or isomer, of dichloroethane was detected.
1,2-Dichloroethane can be found near industries where it is made or used. Typically, it does not stay in the air very long because it is readily broken down by sunlight. ATSDR reviewed scientific literature to gather information on the effects from breathing 1,2-dichloroethane in ambient air. Only very limited data are available. These data suggest that brief exposure to much higher levels than reported in the 1988 study could result in adverse health effects. No human studies are available to show that 1,2-dichloroethane is a carcinogen, and animal studies have yielded mixed results.
Maximum 1-hour ozone levels measured in Louisville between 1980 and 1997 (192-387 µg/m3) frequently exceeded the NAAQS (236 µg/m3 ). Ozone occurs naturally in the stratosphere to provide a protective layer high above the earth; however, at ground-level it is the prime ingredient of smog. It is formed when the nitrogen oxides produced by automobiles, and other sources of combustion, react with VOCs in the atmosphere. Automobiles are the primary source of ozone. At levels around 590 µg/m3, ozone can irritate the nose and throat, cause chest congestion, and at high levels (3,900 µg/m3) produce severe coughing and trouble with concentration. Some exposed individuals may even become more susceptible to respiratory illnesses, such as bronchitis and pneumonia (EPA, 1997). Although detected concentrations frequently exceeded NAAQS guidelines, they are lower than levels associated with documented health effects.
Vinyl chloride was not detected in Louisville air in 1988. Vinyl chloride was detected, however, at 5.9 ppm in 1956--a level substantially higher than typically found in industrial areas where the chemical is used or produced. OSHA has established an occupational standard of 1 ppm for vinyl chloride in air. Prior to the early 1970s when the standard was set, using or producing vinyl chloride had few controls to reduce the amount of chemical emitted to the air.
Like benzene, vinyl chloride health effects information largely comes from occupational studies. In fact, no studies have shown a link between ambient air exposures of vinyl chloride and cancer. Brief exposures (about 5 minutes) to high levels (up to 8,000 ppm) of vinyl chloride have not resulted in serious, lasting health effects. Longer exposures have resulted in headaches, dizziness and respiratory problems. Workers breathing vinyl chloride (at levels of several hundred ppm) over long periods have developed liver and bone disease. Exposure has also been associated with liver cancer (Byren, 1976; Creech and Johnson, 1974; Infante, 1976; Monson, 1975) and cancer of the respiratory tract (Belli, 1987; Infante, 1976; Monson, 1975; Waxweiler, 1976). The levels associated with these effects are much higher than that reported during the 1956 air study. Vinyl chloride may also be associated with brain cancer and cancer of the lymphatic/hematopoietic system; however, studies reporting these effects have had conflicting results.
The 1956 data indicate that some exposure was occurring at a level higher than the current occupational standard (1 ppm); however, the detected concentration is still several orders of magnitude lower than concentrations associated with chronic human health effects. Vinyl chloride was not detected in the air in 1988.
Matanowski et al. 1989. Nested case-control study of lymphopoietic cancers in workers in the styrene-butadiene polymer manufacturing industry (final report prepared under contract to International Institute of Synthetic Rubber Producers, Inc.). The Johns Hopkins University School of Hygiene and Public Health, Baltimore, Maryland.
Shacklette HT, Boergen JG. 1984. Element concentrations in soils and other surficial materials of the contiguous U.S. Geological Survey Profession Paper 1270. Washington DC. Government Printing Office, 1984. (cited in ATSDR's Public Health Assessment Guidance Manual, March 1992).
ATSDR's Comparison Values
ATSDR comparison values are media-specific concentrations that are considered to be "safe" under default conditions of exposure. They are used as screening values in the preliminary identification of "contaminants of concern" at a site. The latter is, perhaps, an unfortunate term because the word "concern" may be misinterpreted as an implication of "hazard". As ATSDR uses the phrase, however, a "contaminant of concern" is merely a site-specific chemical substance that the health assessor has selected for further evaluation of potential health effects.
Generally, a chemical is selected as a contaminant of concern because its maximum concentration in air, water, or soil at the site exceeds one of ATSDR's comparison values. However, it cannot be emphasized strongly enough that comparison values are not thresholds of toxicity. While concentrations at or below the relevant comparison value may reasonably be considered safe, it does not automatically follow that any environmental concentration that exceeds a comparison value would be expected to produce adverse health effects. Indeed, the whole purpose behind highly conservative, health-based standards and guidelines is to enable health professionals to recognize and resolve potential public health problems before they become actual health hazards. The probability that adverse health outcomes will actually occur as a result of exposure to environmental contaminants depends on site specific conditions and individual lifestyle and genetic factors that affect the route, magnitude, and duration of actual exposure, and not on environmental concentrations alone.
Screening values based on noncancer effects are obtained by dividing NOAELs or LOAELs determined in animal or (less often) human studies by cumulative safety margins (variously called safety factors, uncertainty factors, and modifying factors) that typically range from 10 to 1,000 or more. By contrast, cancer-based screening values are usually derived by linear extrapolation from animal data obtained at high doses, because human cancer incidence data for very low levels of exposure simply do not exist, and probably never will. In neither case can the resulting screening values (i.e., EMEGs or CREGs) be used to make realistic predictions of health risk associated with low-level exposures in humans.
Listed and described below are the various comparison values that ATSDR uses to select chemicals for further evaluation.
CREG = Cancer Risk Evaluation Guides
EMEG = Environmental Media Evaluation Guides
EPA = Environmental Protection Agency
MCL = Maximum Contaminant Level
MRL = Minimal Risk Level
RfD = Reference Dose
RMEG = Reference Dose Media Evaluation Guide
Cancer Risk Evaluation Guides (CREGs) are estimated contaminant concentrations in water, soil, or air that would be expected to cause no more than one excess cancer in a million persons exposed over a 70-year lifetime, according to EPA estimates. As ATSDR's most conservative comparison value, the CREG merits special attention. Note that this does not mean that exposures equivalent to the CREG are actually expected to cause one excess cancer in a million persons exposed over a lifetime. Nor does it mean that every person in an exposed population of one million has a 1-in-a-million chance of developing cancer from the specified exposure. Although ATSDR CREGs continue to be useful devices for screening carcinogenic substances at a site, they cannot be used to predict cancer incidence rates at a site. Furthermore, the exposure assumptions on which EPA's cancer risk estimates and ATSDR's CREGs are based (i.e., essentially lifetime exposure) seldom apply at contaminated sites.
US Environmental Protection Agency (EPA) values are similar to ATSDR's CREGs and EMEGs in that they are risk-based concentrations derived for carcinogens and noncarcinogens from RfDs and Cancer Slope Factors, respectively, assuming default values for body weight, exposure duration and frequency, etc. Unlike ATSDR values, however, they are available for fish, as well as for water, soil, and air.
Environmental Media Evaluation Guides (EMEGs) are concentrations of a contaminant in water, soil, or air that are unlikely to be associated with any appreciable risk of deleterious noncancer effects over a specified duration of exposure. EMEGs are derived from ATSDR minimal risk levels by factoring in default body weights and ingestion rates. Separate EMEGS are computed for acute (<14 days), intermediate (15-364 days), and chronic (>365 days) exposures.
Maximum Contaminant Levels (MCLs) represent contaminant concentrations in drinking water that EPA deems protective of public health (considering the availability and economics of water treatment technology) over a lifetime (70 years) at an exposure rate of 2 liters of water per day.
Minimal Risk Levels (MRL) are estimates of daily human exposure to a chemical (i.e., doses expressed in milligrams/kilogram/day [mg/kg/day]) that are unlikely to be associated with any appreciable risk of deleterious noncancer effects over a specified duration of exposure. MRLs are derived for acute (< 14 days), intermediate (15-364 days), and chronic (> 365 days) exposures. MRLs are published in ATSDR's Toxicological Profiles for specific chemicals.
(EPA's) Reference Dose (RfD) is an estimate of the daily exposure to a contaminant unlikely to cause noncarcinogenic adverse health effects over a lifetime of exposure. Like ATSDR's MRL, EPA's RfD is a dose expressed in mg/kg/day.
Reference Dose Media Evaluation Guide (RMEG) is the concentration of a contaminant in air, water or soil that corresponds to EPA's RfD of RfC for that contaminant when default values for body weight and intake rates are taken into account.
ATSDR evaluates contaminants detected in environmental media at the site and determines whether an exposure to them has public health significance. ATSDR selects and discusses the contaminants based upon the following factors:
- concentrations of contaminants on and off site;
- community health concerns; and
- comparison of on- and off-site concentrations with ATSDR health comparison values for (1) noncarcinogenic endpoints and (2) carcinogenic endpoints.
ATSDR health comparison values are concentrations of contaminants which are media specific (e.g., water, air, or soil). The comparison values are considered to be safe under default conditions of exposure and are used as screening values in the preliminary identification of site-specific "contaminants of concern." The "contaminants of concern" are those contaminants that were detected above the screening comparison values and contaminants without comparison values. However, the comparison values listed in the Tables in Appendix A are those that ATSDR considers to be the most appropriate, considering site-specific conditions of exposure, i.e., specifically the duration of exposure (acute, intermediate or chronic) to the environmental medium in question most likely to prevail at the site. Please refer to the Toxicological Evaluation section and Appendix D for further clarification and description of the comparison values used in this public health assessment.
Following the preliminary identification of site-specific "contaminants of concern" which are described in the Environmental Contamination section, ATSDR staff determined whether nearby residents are exposed to contamination migrating from the site in the Pathways Analyses section of this public health assessment. If exposure to contamination is identified, the significance of this exposure with relation to adverse health effects is discussed in the Toxicologic Evaluation section. ATSDR staff also address specific community concerns in the Community Concerns Discussion section of this public health assessment. Lastly, based on the evaluations from all preceding sections of the public health assessment, ATSDR staff determine conclusions and prepare recommendations.
ATSDR has conducted three visits to the Rubbertown area to meet with residents, officials, and industry representatives, and obtain information about the site.
In February, 1993, ATSDR performed an initial scoping visit in response to the community petition. ATSDR representatives attended a Citizen Advisory Committee meeting, toured the neighborhood, and met with the media, the Jefferson County Health Department, and JCAPCD. In addition, ATSDR held a small group meeting at a local church to discuss the health concerns of the community. Following this site visit, ATSDR recommended to local agencies that air monitoring be established in the community (ATSDR, 1993a, 1995).
In January, 1995, ATSDR revisited the site to participate in a meeting concerning collaborative monitoring and health evaluation activities, and to continue to communicate with community members. The collaborative meeting was led by the Jefferson County Health Department and included representatives from the University of Louisville, the JCAPCD, Zeon Chemicals, American Synthetic Rubber, and Rohm and Haas. Initiation of air monitoring and biomarker evaluation studies was discussed at this meeting. ATSDR's community meeting was held at a local church and was attended by six residents (ATSDR, 1995).
In March, 1998, ATSDR made another site visit to obtain an update on air monitoring and community activities. ATSDR representatives toured the site with a researcher from the University of Louisville and a representative of the Kentucky Paddlewheel Alliance, a local environmental group. Subsequently, ATSDR and EPA Region 4 staff attended a meeting of the West County Community Task Force. EPA staff outlined their proposal to start a "Community-Based Environmental Protection" (CBEP) program in the West Louisville area. ATSDR and EPA staff also met with industry representatives to explain the CBEP program (ATSDR, 1998).
References: Please refer to the main reference section.
Many state and local health agencies collect data on the number of people who have been diagnosed with cancer each year and classifies these cancer cases into different categories such as lung, skin, liver, breast, prostate, colon, and so forth, defined by the type of cell in the body that is affected. Depending on the type of data available, the rate of specific cancers can be determined for certain populations within a state, an entire state population, or the entire United States population. The Kentucky Cancer Registry has collected information on all reported new cancer cases diagnosed in the state, since 1991. Cancer "incidence" is the number of newly diagnosed cases of cancer during a particular time period, usually in years. This number is compared to a population where the cancer rates would be stable and represent the normal number expected in a population of a particular size. ATSDR reviewed health statistics from two reports prepared by Kentucky Health Departments using Kentucky Cancer Registry data. Based on the data reviewed ATSDR provides the following summary.
- Report of 1991 Cancer Incidence for Jefferson County (Kentucky Cancer Registry, 1992). Cancer incidence rates for Jefferson County during the year 1991 were compared with the 1991 Kentucky and 1989 National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) age-adjusted incidence rates for all types of cancers combined and specific cancers of concern to the community including lung, breast, colorectal, prostate, and invasive cervical cancer. Results indicated that cancer incidence rates for Kentucky were similar to rates found in the SEER population, or normal cancer rates that would be expected in a population of the same size. However, the occurrence for the types of cancers defined above for Jefferson County were found to be slightly higher than cancer rates for either the Kentucky or the SEER populations. Because individual case information was not available for review, ATSDR is not able to determine wether this slight increase is due to variability in the data or is statistically significant and not due to chance. When the stage of diagnosis (i.e., how advanced the cancer was when detected) was examined, it was found that the diagnosis for African Americans living in Jefferson County is significantly later than for Whites for all types of cancers combined, lung, breast, and cervix cancer. No difference in the age at diagnosis was reported for all types of cancers combined, but African Americans were diagnosed at a younger age than Whites for lung and colon cancer, while at an older age for cancer of the cervix.
- Cancer Mortality and Incidence in Jefferson County, Kentucky: A Summary (Louisville and Jefferson County Board of Health, 1997). The Louisville and Jefferson County Board of Health convened an expert panel to examine differences, if any, between the cancer incidence rates (occurrence of cancer) and mortality rates (deaths due to cancer) across Jefferson County geographic boundaries defined by zip codes and health planning areas. Five county planning areas (west, east, southwest, south, and southeast) were defined by zip codes. Cancer incidence rates and cancer mortality rates were evaluated using cancer and vital statistics data (death certificates) from 1992-1994. A rate ratio is the comparison of the incidence rate of disease (cancer in this case) or death rate in two populations. A ratio with a value of 1.0 or less than 1.0, assumes a null hypothesis, that is, the cancer incidence in the two populations are the same or there are fewer cancer cases in the observed population than expected. In other words, no increase in cancer is observed in the population. Conversely, a ratio higher than 1.0, shows that there were more cases in the community than expected. This ratio is tested for significance or whether the observed number of cases is truly elevated or possibly due to other factors such as a small population size, years observed, inaccurate data, life style, or other risk factors that may influence the results.
The Jefferson County Board of Health study indicated that the incidence of cancer for the five planning areas of Jefferson County did not differ from each other, and the rates for Jefferson County were not different when compared to rates for the state of Kentucky. In general, cancer mortality rates for the 5 planning areas (east, west, southwest, south, and southeast) differed slightly from each other, and the West County planning area had a slightly higher rate ratio than other areas when compared to Jefferson County (1.23) or Kentucky (1.3). While these ratios were slightly higher, the statistical significance of these values were not presented and individual case data was not presented for review. Colon, esophagus, oral, respiratory, and cervical cancer incidence rates were slightly higher in the West County Planning Area; respiratory cancer accounted for the greatest percentage of new cancer cases. The West County planning area had slightly higher mortality rates for liver, oral, ovary, and prostate cancers. Residents of the West County planning area were found more likely to be diagnosed with cancer later and develop the types of cancers often diagnosed in the later stages of the disease (colon and lung) and have a high death rate. While other risk factors (available health care such as prevention and early diagnosis), diet, and lifestyle choices have not been investigated, the West County planning area has been defined with the highest percentage of African American residents (61.4 %), the lowest median household income, highest mean percent of residents 65 years and older, highest mean percent poverty overall and for children in poverty. These are all risk factors that are known to increase disease incidence and that may be addressed through improved health care and intervention methods such as education and prevention.
Cancer is a complex disease that often involves multiple "risk" factors, such as environment, lifestyle (smoking, drinking, diet, etc.), and family history. The reports define their limitations and biases in that they did not account for any of these "risk" factors. Furthermore, analyzing cancer patterns by zip code may be arbitrary and an inexact way of assessing the relationship between geographic location and cancer. For example, the zip code recorded on the death certificate, or in the Kentucky Cancer Registry, may not be where the person resided most of his or her life. However, they may help in defining areas to target for further health care strategies. Because specific environmental exposures and other health risk factors are not known, ATSDR cannot conclude any association between Rubbertown contaminants and the incidence or mortality of cancer in the Jefferson County or the West Jefferson County planning area. However, ATSDR concurs with the recommendations of the Louisville and Jefferson County Board of Health to implement a better health care delivery system, intervention strategies, health education, and community involvement within the five planning areas of Jefferson County.
Biomarkers are measurable substances in the body that may indicate exposure to a particular substance. ATSDR reviewed information from biomarker research being conducted by the CEHS. The CEHS developed procedures for detecting the presence of specific forms of acrylonitrile in human blood, and pilot-tested their procedures among Rubbertown residents. The aim of the research was to determine whether individuals were being exposed to acrylonitrile and to follow the individuals to determine whether they have experienced health effects as a result of exposure. The results are not yet available. ATSDR will review these data once they are available and discuss the results as appropriate.
References: Please refer to the main reference section.
The process of taking in, as when a sponge takes up water. Chemicals can be absorbed through the skin into the bloodstream and then transported to other organs. Chemicals can also be absorbed into the bloodstream after breathing or swallowing.
Occurring over a short time, usually a few minutes or hours. An acute exposure can result in short-term or long-term health effects. An acute effect happens a short time (up to 1 year) after exposure.
Surrounding. For example, ambient air is usually outdoor air (as opposed to indoor air).
A typical or average level of a chemical in the environment. Background often refers to naturally occurring or uncontaminated levels.
Any substance that may produce cancer.
The Comprehensive Environmental Response, Compensation, and Liability Act of 1980, also know as Superfund. This is the legislation that created ATSDR.
Occurring over a long period of time (more than 1 year).
Estimated contaminant concentrations in specific media that are not likely to cause adverse health effects, given a standard daily ingestion rate and standard body weight. The comparison values are calculated from the scientific literature available on exposure and health effects. Please refer to Appendix E for further information on comparison values.
The amount of one substance dissolved or contained in a given amount of another. For example, sea water contains a higher concentration of salt than fresh water.
Any substance or material that enters a system (the environment, human body, food, etc.) where it is not normally found.
Referring to the skin. Dermal absorption means absorption through the skin.
The amount of substance to which a person is exposed. Dose often takes body weight into account.
The presence of hazardous substances in the environment. From the public health perspective, environmental contamination is addressed when it potentially affects the health and quality of life of people living and working near the contamination.
Contact with a chemical by swallowing, by breathing, or by direct contact (such as through the skin or eyes). Exposure may be short term (acute) or long term (chronic).
A source of risk that does not necessarily imply potential for occurrence. A hazard produces risk only if an exposure pathway exists, and if exposures create the possibility of adverse consequences.
Health Outcome Data
A major source of data for public health assessments. The identification, review, and evaluation of health outcome parameters are interactive processes involving the health assessors, data source generators, and the local community. Health outcome data are community specific and may be derived from databases at the local, state, and national levels, as well as from data collected by private health care organizations and professional institutions and associations. Databases to be considered include morbidity and mortality data, birth statistics, medical records, tumor and disease registries, surveillance data, and previously conducted health studies.
Swallowing (such as eating or drinking). Chemicals can get in or on food, drink, utensils, cigarettes, or hands where they can be ingested. After ingestion, chemicals can be absorbed into the blood and distributed throughout the body.
Breathing. Exposure may occur from inhaling contaminants because they can be deposited in the lungs, taken into the blood, or both.
Soil, water, air, plants, animals, or any other parts of the environment that can contain contaminants.
Illness or disease. Morbidity rate is the number of illnesses or cases of disease in a population.
parts per million (ppm):
A unit of concentration specifying the amount of substance in a million parts of another material. One ppm is the same as 1 milligram per liter (mg/L) in water or 1 milligram per kilogram (mg/kg) in soil or sediment. Air concentrations expressed in parts per million represent one molecule of a substance per one million molecules of ambient air; these can be converted to mg/m3 but the conversion factor depends on the molecular weight of the substance in question.
parts per billion (ppb):
A unit of concentration specifying the amount of a substance in a billion parts of another material. One ppb is 1,000 times lower than one ppm. One ppb is the same as 1 microgram per liter (g/L) in water or one microgram per kilogram (g/kg) in soil or sediment. Air concentrations expressed in parts per billion can be converted to a weight per volume expression, taking into account the molecular weight of the substance being measured.
No Apparent Public Health Hazard
Sites where human exposure to contaminated media is occurring, or has occurred in the past, but the exposure is below a level of health hazard.
No Public Health Hazard
Sites for which data indicate no current or past exposure ,or no potential for exposure, and therefore no health hazard.
Petitioned Public Health Assessment
A public health assessment conducted at the request of a member of the public. When a petition is received, a team of environmental and health scientists is assigned to gather information to ascertain, using standard public health criteria, whether there is a reasonable basis for conducting a public health assessment. Once ATSDR confirms that a public health assessment is needed, the petitioned health assessment process is essentially the same as the public health assessment process.
Potential/Indeterminate Public Health Hazard
Sites for which no conclusions about public health hazard can be made because data are lacking.
The condition where valid information, usually analytical environmental data, indicates the presence of contaminant(s) of a public health concern in one or more environmental media contacting humans (i.e., air, drinking water, soil, food chain, surface water), and there is evidence that some of those persons have an identified route(s) of exposure (i.e., drinking contaminated water, breathing contaminated air, having contact with contaminated soil, or eating contaminated food).
An opportunity for the general public to comment on Agency findings or proposed activities. The public health assessment process, for example, includes the opportunity for public comment as the last step in the draft phase. The purposes of this activity are to : (1) provide the public, particularly the community associated with a site, the opportunity to comment on the public health findings contained in the public health assessment; (2) evaluate whether the community health concerns have been adequately addressed; and (3) provide ATSDR with additional information.
Public Health Action
Designed to prevent exposures and/or to mitigate or prevent adverse health effects in populations living near hazardous waste sites or releases. Public health actions can be identified from information developed in public health advisories, public health assessments, and health consultations. These actions include recommending the dissociation (separation) of individuals from exposures (for example, by providing an alternative water supply), conducting biologic indicators of exposure studies to assess exposure, and providing health education for health care providers and community members.
Public Health Hazard
Sites that pose a public health hazard as the result of long-term exposures to hazardous substances.
In risk assessment, the probability that something will cause injury, combined with the potential severity of that injury.
Route of Exposure
The way in which a person may contact a chemical substance. For example, drinking (ingestion) and bathing (skin contact) are two different routes of exposure to contaminants that may be found in water.
A document about a specific substance in which ATSDR scientists interpret all known information on the substance and specify the levels at which people may be harmed if exposed. The toxicological profile also identifies significant gaps in knowledge of the substance, and serves to initiate further research, where needed.
Urgent Public Health Hazard
Sites that pose a serious risk to the public health as the result of short-term exposures to hazardous substances.
Volatile organic compounds (VOCs)
Substances containing carbon and different proportions of other elements such as hydrogen, oxygen, fluorine, chlorine, bromine, sulfur, or nitrogen; these substances easily become vapors or gases. A significant number of the VOCs are commonly used as solvents (paint thinners, lacquer thinner, degreasers, and dry cleaning fluids).
Reference for Glossary:
ATSDR has summarized the comments received during the public comment period of the Rubbertown Industrial Area public health assessment. Each comment was logged and became part of the administrative record. Both the comments (without indication of who made them) and ATSDR's responses are included in the text below. The comments have been numbered and are in italics with ATSDR's response directly below each. The first several comments are "general statements" about the public health assessment. The remaining comments reference specific sections and subsections of the public health assessment.
1. General Statement: Please spell out all acronyms at their first usage even though a list of acronyms is provided at the beginning of the document. This is done in some instances, but not in others. For example, page 8, line 3 uses the acronym EMEG without prior definition.
All acronyms have been spelled out at their first usage. For example, the acronym EMEG was previously spelled out on page 7, lines 7 and 8.
2. General Statement: Please use standard units of concentration for all environmental media (i.e., mg/kg for soil, ug/m3 for air, etc.) rather than ppm, ppb, etc.; the former are exact, unambiguous statements of concentration, whereas the latter are less straightforward and confusing. Additionally, a brief description of concentration terms would be helpful to the reader.
The concentration units ppm, ppb, etc., are equivalent to the concentration units mg/kg, ug/m3, etc.; therefore, no units have been changed in this public health assessment. To avoid confusion, ATSDR has added a brief description of concentration terms to the Glossary in Appendix H.
3. General Statement: It would be helpful if additional clarification is added to the summary or background section to indicate that there are other industries in the area that are not part of Rubbertown, but that may be impacting, in a holistic sense, the health of the community. The West County Community Task Force identified particulate matter, particularly from the Gallagher utility plant in Indiana, as one of their top six concerns. Additionally, there may be other contaminants that are not associated with the industries, but are nevertheless present, such as smoking and indoor air issues. These are certainly cancer-causing agents. Only radon was mentioned. A strong acknowledgment that ATSDR is looking at a subset of all risk factors should be included, as all of these elements add to the overall risk to the community.
ATSDR stated in the third paragraph of the Site Description and History section of this public health assessment that "Potential health hazards exist in the West Louisville area which are not related to the Rubbertown industries." ATSDR then went on to further clarify a few of these potential health hazards, including radon, lead paint, and mobile source air pollution. While this list was not meant to be exclusive (as indicated by the word 'include'), in response to this comment, ATSDR has added ". . .other industries not a part of Rubbertown, smoking, and indoor air issues" to the list of potential health hazards. Of note, this public health assessment is in response to a petition concerning the Rubbertown industries. While ATSDR acknowledges these additional potential health hazards, the focus of this public health assessment is on the impacts of the Rubbertown industries.
4. General Statement: Why were other environmental databases not considered (e.g., RCRIS, CERCLIS, LUST, POTW violations, fish advisories)?
In general, ATSDR public health assessments focus on chemicals of concern detected in the environmental media individuals are most likely to be exposed to (e.g., air, soil, water, etc.). ATSDR gathered all relevant environmental data for the Rubbertown area that was available. Many of the Rubbertown industries have also collected on-site groundwater and soil data associated with the release of contaminants in the past from overflows, spills, leaks, etc. However, because ATSDR focused this public health assessment on exposures to residents living in the vicinity of Rubbertown and not on exposures to workers, on-site data for each Rubbertown industry was not collected and reviewed. ATSDR did review environmental data for off-site media to which residents are potentially exposed (e.g., residential soil, fish, and air). Of note, ATSDR did discuss areas that are posted against fishing, swimming, etc. (Please refer to the Pathway Analyses section of the public health assessment for this information.)
5. General Statement: Were incidents of asthma considered as an adverse health effect in this document (because this area is in nonattainment of the ozone NAAQS), or did ATSDR just look at incidents of the types of cancer listed in the document?
Please refer to the Community Concerns Discussion section, bullet two, for information on asthma.
6. Background and Statement of Issues, Site Description and History, Paragraph 3, Sentence 4: In 1978, lead-based paint was banned from use in residential areas, although it was phased out in the years between 1950 and 1978. The percentage of homes built between 1950 and 1978 should also be considered in some fashion. It would also be helpful to point out that the ban was enacted in 1978 and clarify the rationale for using the year (or years) chosen as a cut-off.
ATSDR thanks the commentor for this information; however, the sentence in question came from a JCDEHP report, not an ATSDR analysis, and therefore cannot be modified. ATSDR used the information from the JCDEHP report in the public health assessment only to emphasize that a large percentage of homes are older and likely contain lead-based paint. Please contact the JCDEHP directly to obtain information on their rationale for using 1950 as a cut-off year.
7. Environmental Contamination and Other Hazards, Paragraph 1: Please explain why no surface water or groundwater data were obtained as part of this evaluation. While reasons for not collecting such data are presented later in the document, an up-front rationale for the selection of the environmental media to be evaluated would be helpful.
ATSDR has deleted the sentence in this paragraph that states no surface water or groundwater data were obtained to avoid confusing the reader. The rationale is based on an evaluation of human exposure pathways which are explained and discussed in the Pathway Analyses section.
8. Environmental Contamination and Other Hazards, Contamination by Medium, Air, Paragraph 1: This paragraph refers to the "West End residential area." However, this area is not indicated on any map, nor its location clearly identified in the text. Because the location of this area plays a crucial role in the ensuing discussion, its unambiguous location on the map, along with a more explicit description in the text, would be helpful.
The "West End" is a term loosely used by many organizations and documents to refer to the western part of the city of Louisville, possibly including some unincorporated areas of Jefferson County. The most distinct definition ATSDR found was provided in the 1997 Louisville and Jefferson County Board of Health cancer report, which defined the "West County Planning Area" by the zip codes 40202, 40203, 40208, 40210, 40211, and 40212. Unfortunately, the map containing these zip code areas does not photocopy clear enough for inclusion in this public health assessment.
9. Environmental Contamination and Other Hazards, Contamination by Medium, Air, Paragraph 6: Please indicate the location of the air monitors used for the evaluation of criteria pollutants. Further, some mention of the change in the ozone NAAQS from 1-hour to the 8-hour standard would be helpful. In addition, this paragraph should discuss the attainment status of the area for the other criteria pollutants. A statement that no other criteria pollutants exceeded their NAAQS would be helpful.
ATSDR has included a map of the ozone monitoring locations in Appendix B. The 1998 JCAPCD report compared ozone levels to the NAAQS 1-hour 0.12 ppm standard, which existed at the start of the 1997 monitoring year. In July, 1997, EPA promulgated a new NAAQS for ozone, which is a daily maximum 8-hour running average ozone concentration of 0.08 ppm. This standard will require reclassification of nonattainment areas. However, analysis provided in the JCAPCD report suggests that Louisville will continue to be a nonattainment area under the new standard if ambient ozone levels remain the same as in recent years. ATSDR added the statement, "no other criteria pollutants exceeded NAAQS standards," to the main text.
10. Environmental Contamination and Other Hazards, Contamination by Medium, Soil, Paragraph 3 (deleted): This paragraph leaves the impression that soil lead contamination is more likely derived from crumbling lead-based paint than industrial sources. Because the issue of industrial sources was not assessed, and because the exact location of the soil samples is apparently unknown, this paragraph should be reworded so it is less suggestive as to the source of the lead. Specifically, soil lead concentrations are likely to be influenced by lead-based paint only if the soil sample is taken in the near vicinity of a painted structure. As such, industrial sources and historical deposition from the use of leaded gasoline cannot be ruled out and no implication as to the source of elevated lead should be made.
ATSDR has deleted the paragraph in question so the public health assessment is less suggestive as to the source of the lead in this section.
11. Environmental Contamination and Other Hazards, Contamination by Medium, Fish, Paragraph 1: Please show the location of Chickasaw Park Lake on the map as it plays a significant role in the discussion.
12. Environmental Contamination and Other Hazards, Quality Assurance and Quality Control, Paragraph 1: This section should mention QA/QC issues regarding sediment, for the sake of consistency with the preceding discussion on sediment. Also, this paragraph should explicitly state how the availability (or lack) of adequate QA/QC procedures and documentation affected ATSDR's decision-making process in evaluating data and using them for conclusions and recommendations.
ATSDR added sediment to the paragraph in question. ATSDR did state explicitly how quality assurance and quality control measures affect the conclusions and recommendations in the last two sentences of this paragraph.
13. Pathway Analyses, Potential Exposure Pathways, Air: It is not clear why air is considered a "completed" exposure pathway (as opposed to a "potential" exposure pathway), as the only data for air contaminants in the vicinity of Rubbertown (the 1950's studies) are questionable with regard to QA/QC. This could be clarified by explicitly stating on page 9 (QA/QC Section) that the 1950's data, while of questionable quality, will be treated as positive detections of air contaminants for the purposes of this study.
After careful consideration, ATSDR has modified the public health assessment to indicate that air is a potential pathway. This modification was made because the representativeness of available air data are uncertain, and the length of time people may have been exposed to detected contaminants is unknown. Also, as suggested by the commentor, ATSDR has clarified the Quality Assurance and Quality Control (QA/QC) section.
14. Pathway Analyses, Potential Exposure Pathways, Fish (Past): Please cite the particular "EPA risk-based approach" used. There are too many to determine which one is used based on the discussion provided.
The following reference has been added: EPA. 1989. Risk Assessment Guidance for Superfund, Volume 1 -- Environmental Evaluation Manual, Office of Emergency and Remedial Response, Washington, DC. EPA/540/1-89/002.
15. Pathway Analyses, Eliminated Exposure Pathways, Groundwater: It would be helpful to state whether the city water intake from the Ohio River that services the Rubbertown area is above or below the Rubbertown area. Because it is unknown whether groundwater in the area is discharging to the river, knowing that the intake is hydraulically up gradient of Rubbertown would substantiate the assertion that drinking water is not being adversely affected by groundwater impacted by the Rubbertown area.
The following caveat would be helpful: While drinking water systems are routinely tested for a wide variety of substances, not all chemicals are assessed. Specifically, a public water system that has no reported violations of the Safe Drinking Water Act requirements may, nevertheless, have unassessed contamination, especially if the surface water from which it is derived is adversely affected by impacted industrial groundwater sources with nonstandard contaminants.
Further, stating whether any sort of groundwater well survey was performed (e.g., review of USGS databases, windshield survey, discussions with residents) to determine groundwater use in the area would be helpful.
The municipal supply intake from the Ohio River is hydraulically upgradient of Rubbertown so public drinking water is not being adversely affected by the Rubbertown area. The 'caveat' provided in this comment was not added to the main text as Rubbertown is downgradient of the municipal water supply. ATSDR has not identified any documentation indicating that private drinking water supply wells exist in the area. ATSDR is not aware of any groundwater well surveys.
16. Pathways Analyses, Eliminated Exposure Pathways, Fish (Present), Paragraph 1: The City of Louisville restocked Chickasaw Park Lake with bluegill and bass fish; however, it appears that carp have been put in the lake from the Ohio River. Resampling of the fish indicated dioxin in the carp, but not the bluegill or bass. There is no information on whether individuals are continuing to eat fish caught in the lake.
Please refer to comment number 23. The City of Louisville will be conducting a "Metro Parks Lake and Pond Dioxin Study", which will involve analysis of fish and sediment samples collected from 10 city park lakes over a 2-year period, beginning in September 1998. ATSDR plans to evaluate additional data collected for the Rubbertown area. As ATSDR stated in the Pathway Analyses section, only catch-and-release fishing is currently allowed in Chickasaw Park Lake.
17. Public Health Implications, Toxicologic Evaluation, Paragraph 2, Line 1: Please use a word other than "harmless" to convey information regarding the potential public health implications of exposures. In particular, exposures to carcinogenic substances are normally assumed to carry a finite nonzero lifetime risk, even if the exposure is low in concentration and short in duration. Many stakeholders would object to such a risk as being termed "harmless." An alternate phrase such as "acceptably low risk" might better serve to convey idea that any residual risk is of little to no concern. (This same term is again used on page 14, first full paragraph. See also Page 48 and the use of the term "safe.")
"Acceptably low risk" is a relative term, as levels of risk that are "acceptable" to one person may be unconscionably high to another. "Acceptably low risk" can also be a misleading phrase for the general reader, as the word "risk," as used by risk assessors, bears little resemblance to the public's (and Webster's) definition of the term. As stated in EPA's 1986 Guidelines for Carcinogen Risk Assessment, "the true risk is unknown and may be as low as zero." Unfortunately, the general public tends to take cancer risk numbers literally in the mistaken belief that so-called quantitative cancer risk assessments actually do quantify "true risk." Thus, for most readers of ATSDR's public health assessments, numerical, single-point estimates of cancer "risk" tend, in practice, to be less illuminating than they are unduly alarming. For this reason, most ATSDR health assessors find that a qualitative discussion of the site-specific factors influencing cancer risk tends to be more informative to the reader. ATSDR considers "harmless" to be the more appropriate word, in this particular context.
18. Public Health Implications, Toxicologic Evaluation, Chemicals of Concern in Air, Paragraph 1, Sentence 3: Please clarify why ATSDR is more concerned with average air concentrations than concentration excursions (as is implied by this paragraph). Because it was the air pathway excursions that prompted the public health petition, it may not be prudent to downplay their significance or relevance. Also, an additional reason as to why the results of the 1950s studies may be less relevant could be added. Specifically, the industrial processes of the surrounding facilities may have changed appreciably over the years and the ambient air concentrations evaluated in the 1950s may not be reflective of these current area industrial processes.
ATSDR does not believe the paragraph in question implies that we are more concerned with "average" air concentrations. ATSDR used the word "average" in the public comment version of this document to indicate "chronic" exposure levels, and has modified this sentence. Further, ATSDR refers the reader to Appendix C, which includes information on the historical data, in paragraph 3 of this section. ATSDR thanks the commentor for the additional reason why the results of the 1950s air data may not reflect current conditions.
19. Public Health Implications, Toxicologic Evaluation, Chemicals of Concern in Soil, Paragraph 1: This paragraph (and other sections of the document) refers to "off-site" areas. It would be helpful to clearly articulate in the text what constitutes "on site" and "off site" areas and how the distinction was made (the only apparent reference to on site vs. off site is in the legend of the Rubbertown area map).
ATSDR has modified the Environmental Contamination and Other Hazards section to state, "For the purpose of this public health assessment, ATSDR considers "on site" to refer to the Rubbertown industries and "off site" to refer to all other areas, including residences, parks, and other commercial and industrial properties not a part of Rubbertown."
20. Public Health Implications, Toxicologic Evaluation, Chemicals of Concern in Soil, Paragraph 2: We suggest that, given the paucity of data regarding the source of lead in soils, as well as, the range of concentrations found, it would be useful to identify soil sampling as a data need with lead as a primary analyte of concern. The rationale for this is as follows: The EPA has determined, through application of the Integrated Exposure Uptake Biokinetic (IEUBK) model for lead in children, that soil lead concentrations above 400 mg/kg pose a concern warranting further study. The data available to ATSDR (a small number of soil samples at unknown residential locations) are insufficient to conclude anything with regard either to sources of lead or to their distribution in surface soils. Because at least one of the samples was twice as high as EPA's conservative screening value for lead in soil (vide supra), and given the relatively large portion of the population of children with elevated blood lead levels in the area (18% in 1996), we suggest that any soil sampling program in residential areas include lead as a parameter of interest.
ATSDR has modified the Recommendation section of the public health assessment to state, "Expand soil characterization to include metals (especially lead), organic compounds, and polycyclic aromatic hydrocarbons."
21. Recommendations, Recommendation 2: It would be helpful to clarify what, if any, soil sampling efforts are planned for the future. Also, alternative wording should be used for "priority pollutants," as this phrase generally refers to a specific list of chemicals regulated by the Clean Water Act.
While ATSDR has recommended soil sampling, it is unclear at this time if soil sampling efforts will occur in the near future. As stated in the previous comment, the recommendation for soil sampling has been modified with regard to the phrase "priority pollutants".
22. Public Health Actions, Actions Implemented, Paragraph 1: Local government agencies also participate in the West County Community Task Force (WCCTP).
ATSDR has added "local government agencies" to the second sentence of this paragraph.
23. Public Health Actions, Actions Planned, Paragraph 1: The City of Louisville will be conducting a "Metro Parks Lake and Pond Dioxin Study", funded by the Kentucky General Assembly. This investigation will involve analysis of fish and sediment samples collected from 10 city park lakes over a 2-year period, beginning in September 1998. This effort is designed to compare and evaluate dioxin concentrations, and to provide this information in a report to the WCCTF. The city has also been directly involved in follow-up investigation at Chickasaw Lake to further monitor for the presence of dioxins in fish tissue and sediments originally discovered in 1995.
ATSDR thanks the commentor for this information which has been added to the Public Health Actions section of the public health assessment.
24. Public Health Actions, Actions Planned, Paragraph 1: The public comment version of the Health Assessment does not specify further actions by ATSDR. Please specify whether ATSDR expects to play a continuing role in this project area, or whether it deems its work complete with this report.
ATSDR expects to play a continuing role in the Rubbertown project. Please refer to page 23, lines 7 through 10, for further information.
25. Appendix A, Tables: It would be helpful to restate in the Table footnotes that the comparison value selected is the lowest of available criteria for both cancer and noncancer effects (and in the case of noncancer effects, both acute and chronic). The footnotes should also indicate whether the screening value selected is based on default exposure values or on more site-specific data (as is indicated in Appendix E).
ATSDR has added a footnote to each table in this public health assessment stating that further information on comparison values is provided in Appendix D and Appendix E. Additionally, please refer to comment number 29 for further clarification of 'default' and 'site-specific' exposures.
26. Appendix B, Figures, Figure 2: All maps should be expanded to one page each. It is difficult to read the small maps on the second page. Although the Census Bureau collects block data once every 10 years, some states collect their own data, which may be updated more frequently. Kentucky's census data center is located at the Urban Studies Institute at the University of Louisville. Updated information would be particularly useful because, in 1996, 18% of the children in West Louisville had reportedly high blood lead levels (see page 16), but we do not know how many children there are (all of the 1990 census "under 6" category are now over age 6).
ATSDR has a Spacial Analysis section that creates demographic maps for agency documents. The map in question is a standard, 1-mile buffer, demographic map that appears in all public health assessments. This is the preferred format decided on by the agency; therefore, no changes to Figure 2 have been made. Because ATSDR was not able to fully evaluate the issue of lead exposure in the public health assessment, an exact population number for children under 6 was not obtained.
27. Appendix C, Health Implications of Exposure to Air Contaminants: An introductory paragraph for this section indicating why these particular chemicals were selected for further discussion would be helpful.
ATSDR has added an introductory section to Appendix C.
28. Appendix C, Health Implications of Exposure to Air Contaminants, Vinyl Chloride: The use or production of vinyl chloride continues for at least two Rubbertown facilities at the present time. This information has been provided to the WCCTF by the facilities from their Toxics Release Inventory (TRI) Reports for 1995 through 1997. Thus, references in this section of the Health Assessment indicating that vinyl chloride is no longer used or produced in the Rubbertown area are incorrect.
ATSDR has deleted all references in the public health assessment that indicate vinyl chloride is no longer used or produced in Rubbertown.
29. Appendix E, ATSDR Methodology: Please clarify the discussion of comparison values for the following reason: The discussion indicates that comparison values based on default and site-specific exposure assumptions are both protective of public health. While this is generally true, it is not always true as implied by this paragraph. For example, subsistence fishermen may have exposures far exceeding the consumption patterns assumed in deriving a "conservative" health based screening level for fish using default exposure assumptions. In this case, only an assessment using site-specific assumptions would properly characterize the risks posed to such highly exposed persons. With regard to these "site-specific" exposure assumptions, it would be helpful to display (and cite) these values and describe the calculations used in their derivation.
Finally, the statement "Rather, the contaminant will be evaluated in subsequent discussions in the document" is confusing. How does the act of "discussing" a chemical bear upon its potential to cause, or not cause, harm?
Regarding the statement concerning "comparison values based on default and site-specific exposure assumptions...", it should be pointed out that all comparison values listed in the tables for this public health assessment are based on default exposure assumptions; none are based on "site-specific exposure assumptions." ATSDR has modified the text in Appendix E to clarify this point.
The commentor also expressed concern that comparison values based on default exposure assumptions may not be protective of public health under site-specific conditions of exposure. While it is true that fish consumption by subsistence fishermen generally exceeds the default exposure assumptions on which conservative health-based comparison values are based, it is also true that these comparison values are not toxicity thresholds. They typically incorporate large margins of safety that usually dwarf the difference between default and site-specific rates of exposure. Furthermore, the default exposure assumptions themselves often significantly overestimate exposure rates for the great majority of people. Of note, ATSDR does consider subsistence fishermen in our evaluations, when appropriate, and develops comparison values for the site-specific exposure scenario.
With regard to the second paragraph of this comment, ATSDR's evaluation of the contaminants of concern is typically detailed in the Toxicologic Evaluation section. For this public health assessment, ATSDR included an evaluation of the 1950s air data in Appendix C. The "discussion" of each chemical provides ATSDR's evaluation of the potential for the chemical to cause, or not cause, harm at the levels detected.
30. Appendix G, Health Outcome Data Summary, Bullet 1: The statement reading "...for all types of cancers, lung, breast, colorectal, prostate, and invasive cervical cancer" (emphasis added) is ambiguous. Were all types of cancers assessed, or were only this subset of cancers (i.e., lung, breast, colorectal, prostate, and invasive cervical) assessed? Please reword such statements to clarify exactly what types of cancers were assessed.
The statement in Appendix G, Health Outcome Data Summary, Bullet 1, has been modified to clarify the type of cancer data reviewed.
31. Appendix G, Health Outcome Data Summary, Bullet 2, Paragraph 2: This paragraph states that the incidence of cancer for the 5 planning areas of Jefferson County did not differ from each other and that the rates for Jefferson County were not different when compared to rates for the Commonwealth of Kentucky (likewise for the mortality rates). The paragraph then goes on to emphasize how one area the ("West County Planning Area") is different from the other planning areas and highlights factors that may be causing the differences (e.g., income, age, poverty).
If the differences for the West County Planning Area are, in fact, not statistically different from Jefferson County or the Commonwealth as a whole (as previously implied), the paragraph should explicitly state that fact. As written, the reader is left with the possibly incorrect conclusion that there is a definite increase in cancer incidence and mortality in the West County Planning Area and that the increase can likely be attributed to specific demographic and other risk factors.
While statistical significance was not presented in this report, ATSDR has modified this section of Appendix G to clarify this point.
32. Appendix G, Health Outcome Data Summary, Biomarker Research: Please indicate the reason that acrylonitrile, as opposed to some other chemical, was selected for biomarker research.
This appendix only provides a summary of health outcome data. ATSDR did not participate in the studies that were summarized. In the University of Louisville research report dated February 1997, the author states in the first paragraph that acrylonitrile was selected initially for biomarker development because methods exist to measure it in blood samples; it is commonly used, stored and emitted by local industries; and there is concern regarding its health effects. ATSDR suggests that the commentor contact the Center for Environmental Health Sciences (CEHS) for information on the reasons acrylonitrile was selected as CEHS is performing the research.