PATHAN CHEMICAL SITE
PHILADELPHIA, PHILADELPHIA COUNTY, PENNSYLVANIA
At the request of the U.S. Environmental Protection Agency (EPA) in Region III, the Pennsylvania Department of Health (PADOH), working under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR), prepared this health consultation (HC) for the Pathan Chemical Site. ATSDR and PADOH were requested to review the most recent EPA sampling at the site and determine whether the site poses a public health hazard.
The chemicals of health concern selected for evaluation include lead, arsenic, polycyclic aromatic hydrocarbons (PAHs), and asbestos; they were detected in surface soil (0-12 inches) at maximum concentrations of 1,070 milligrams per kilogram (mg/kg), 9.3 mg/kg, 108.5 mg/kg, and 3.13 million structures/gram, respectively. While there are also chemicals of health concern that were detected in background samples (off site) taken from Hetzell Playground, they will be discussed specifically in a separate HC because of chemicals of health concern that are specific to that site and because of a particular interest by the City of Philadelphia Department of Recreation.
The site is currently a vacant lot that is readily accessible to anyone. On the basis of existing preliminary data and current on-site activities, however, ATSDR and PADOH conclude that the site currently poses an indeterminate public health hazard.
The former Pathan Chemical Site (the site), once a 40,000 square foot, four-story warehouse and loading yard, was located in a residential area at 427 Moyer Street, Philadelphia, Pennsylvania (Figure 1 and Figure 2). The site used to be an abandoned, unsecured building with most of the windows and some of the doors broken out, and showed evidence of trespassing and fires. The building was originally a textile facility that was bought by a former employee in 1972 who converted the building to a manufacturing facility for detergents and fabric softeners. From the documents gathered for this HC, there is no information as to when the business was closed .
EPA initially conducted a removal assessment in 1995. The removal assessment identified approximately 10 vats, several hundred drums and approximately 1000 small containers which contained hazardous substances within the building. Many of the drums and small containers were unlabeled and were in deteriorating conditions, leaking their contents. Materials were incompatibly stored, and sections of the floors where materials were stored were in deteriorating condition. The owner of the site attempted to conduct the removal effort but was unable to do so for financial reasons. Three roll-off dumpsters that EPA filled with crushed drums and small containers were removed from the site. When the action was completed, approximately 25 drums and several bags of chemicals were left on site because the property owner declared them as assets. Before leaving the site in 1996, EPA placed these items on the third floor of the building .
As of August 1998, these drums and paper sacks still remained on site. However, the EPA Regional Response Center received information in July 1998 indicating that people were breaking into the building and spilling chemicals on the floor. This initiated a removal assessment being performed by EPA in August 1998 in accordance with the National Oil and Hazardous Substances Pollution Contingency Plan, 40 CFR Part 300. Some of these drums and paper sacks have had their contents spilled on the floor and down the stairwells, constituting a release or threat of release into the environment. Evidence existed of trespassing and vandalism which create an imminent and substantial endangerment to public health and the environment .
Since the building was abandoned, the integrity of the earlier removal efforts conducted in 1996 was threatened. Further removal action was required to eliminate the threat posed by the remaining drums and paper sacks at the site. EPA removed these drums and paper sacks and cleaned up the spilled materials throughout the building on November 3, 1998, through December 14, 1998 . The building caught fire in March 1999 and was destroyed. The city of Philadelphia tore the building down, leveled what was left, and then covered it.
Currently, the site is a vacant lot that is readily accessible to anyone. Row homes are directly adjacent to the west and east boundaries of the site. Located directly north of the site, crossing East Thompson Street, is the Adaire Public School and the Hetzell Playground. Located directly south of the site, crossing Moyer Street, are additional row homes (Figure 3).
On October 19, 2001, government officials from the PADOH Environmental Health Assessment Program, ATSDR Region 3, EPA Region 3, City of Philadelphia Department of Recreation and City of Philadelphia Risk Management Division conducted a site visit.
According to the EPA Region 3 official, the appearance of the Pathan Chemical site has changed more significantly since July 2001 when EPA Region 3 collected soil samples. The overgrown vegetation and trash have been removed, a small treehouse has been constructed at the northeast portion of the property and several household items have been, for some unknown reason, placed on top of the EPA's large storage container .
In July 2001, EPA contractor tested eight (8) soil samples on site . Off site soil samples were also taken from the nearby Hetzell Playground to determine the background levels of chemicals. Samples collected by EPA Region 3 were analyzed for the full scan of inorganics (metals and cyanide) and organics (volatiles, semi-volatiles, pesticides and polychlorinated biphenyls). Additionally, selected on site samples were analyzed for asbestos fibers.
Soil samples were tested at 0-1 foot deep, 5 feet deep and 10 feet deep. Table 1 shows only the chemicals of health concern that have been detected in various surface soil samples (0-1 foot deep) collected from the on site Pathan Chemical Site. These data were used in evaluating the public health threat concerns as a result of the exposure to these chemicals. There are chemicals of health concern that were detected from the off site Hetzell Playground and not found at the former Pathan Chemical Site. As a result, there will be a separate HC for the Hetzell Playground Site.
To determine the possible health effects of site-specific chemicals, ATSDR has developed health-based comparison values (CVs) that are chemical-specific concentrations to help identify environmental contaminants of health concern . We use CVs to determine which contaminants require further evaluation. Chemical concentrations that were below any of the ATSDR's comparison values are not discussed further in this HC.
These CVs include environmental media evaluation guides (EMEGs) and reference dose media evaluation guides (RMEGs) for noncancerous health effects as well as cancer risk evaluation guides (CREGs) for cancerous health effects. If environmental media guides cannot be established because of a lack of available health data, other comparison values may be used to select a contaminant for further evaluation. While media concentrations less than a CV are unlikely to pose a health threat, media concentrations above a CV do not necessarily represent a health threat. Therefore, CVs should not be used as predictors of adverse health effects or for setting clean-up levels.
PADOH also researches scientific literature and uses the ATSDR's minimal risk levels (MRLs), the EPA's reference doses (RfDs), and the EPA's cancer slope factors (CSFs). MRLs are estimates of daily exposure to contaminants below which noncancerous adverse health effects are unlikely to occur. RfDs are estimates (with uncertainty spanning perhaps an order of magnitude) of daily oral exposure, in milligrams per kilogram per day (mg/kg/day), to the general public (including sensitive groups) that are likely to be without an appreciable risk of noncancerous harmful effects during a lifetime (70 years). Doses below the MRL or RfD are not likely to cause any noncancerous adverse health effects. Doses above the MRL or RfD require further evaluation to determine if adverse effects are likely to occur. When RfDs and MRLs are not available, a no observed adverse effect level (NOAEL) or lowest observed adverse effect level (LOAEL) may be used to estimate levels below which no adverse health effects (noncancerous) are expected.
Health guidelines such as MRLs and RfDs, however, do not consider the risk of developing cancer. To evaluate exposure to carcinogens, EPA has established CSFs for inhalation and ingestion that define the relationship between exposure doses and the likelihood of an increased risk of cancer, compared with controls that have not been exposed to the chemical. Usually derived from animal or occupational studies, CSFs are used to calculate the exposure dose likely to result in one excess cancer case per one million persons exposed over a lifetime (70 years).
Because children generally receive higher doses of contaminants than adults under similar circumstances, the DOH uses the higher doses in forming its conclusions about the health effects of exposures to site-related contaminants when children are known or thought to be involved (see Child Health Initiative section). Also readers should note that researchers conduct animal studies using doses at levels much higher than those experienced by most people exposed to chemicals from hazardous waste sites.
The sampling data evaluated in this section were obtained from the 2001 data validation reports for Pathan Chemical Site . After contaminants were selected for further evaluation with the use of ATSDR's Soil Comparison Values, PADOH evaluated the environmental and human components (or exposure pathways) that could lead to human exposure. Exposure pathways are descriptions of the way that a chemical moves from its source (where it began) to where and how people can come into contact with (or get exposed to) the chemical.
In order to properly assess the human health threat associated with exposure to contaminated soil, however, it is important to have the shallow surface soil (0-3 inches) data. Since we do not have such data, we will use the maximum level for all chemicals of health concern in the existing data from surface soil samples (0-12 inches). It is important to note that the concentrations of chemicals from 0-12 inches of surface soil samples might not be representative of the 0-3 inches of surface soil samples. The contaminants could be diluted with uncontaminated soil as the soil sample goes deeper in the sampling process (unless the chemicals are buried underground, as in landfills, which does not appear to be the case in this site). Therefore, the 0-12 inches of soil concentration of a specific chemical could underestimate the amount of chemical in the top 0-3 inches of surface soil.
Data from 5-feet and 10-feet soil samples are not reviewed in this HC because there are no completed exposure pathways to soils at depth and because the levels of chemicals detected are generally lower than those found from the 0-12 inches of surface soil samples.
PADOH considered the scenario that deals with exposures of trespassers to onsite soil through ingestion (from 1996 when EPA conducted a removal action at the site through 2001 for a total exposure duration of 5 years). The worst case assumption in this case involves the highest levels of contaminant detected for children (58 kg) who would have been playing for 4 hours per day for 5 days a week for 12 weeks during summer months and who would also have been playing for 2 hours per day for 2 days a week for the rest of the school year which totals 40 weeks. This will result to a total of 17 days/year of exposure. It would also be logical to assume that the exposure dose would be less for adults since we do not expect adults to be spending as much time as the children in this site. Furthermore, it is assumed that the soil ingestion rate for children is 200 mg/day and the soil ingestion rate for adults is 100 mg/day .
As indicated, people who visited the site (especially children) may have been exposed to arsenic through the ingestion of surface soil. Skin contact with arsenic in soil is not an important route of exposure because very little arsenic can enter the body through skin .
Arsenic was detected in all of the eight surface soil samples (0-12 inches); levels ranged from 3.3 mg/kg to 9.3 mg/kg at the site. These levels are lower than the Pennsylvania Department of Environmental Protection's (PADEP's) current Act 2 residential clean up standard for arsenic of 12 mg/kg and a nonresidential standard of 53 mg/kg. As stated earlier, proper evaluation of the public health threat requires data from shallow (0-3 inches) soil. In the absence of those data, we have used the maximum arsenic contamination level (9.3 mg/kg) obtained from the 0-12 inches of surface soil samples to estimate the exposure dose.
In general, the concentration of arsenic in soil varies widely across the United States, ranging from about 1 mg/kg to 40 mg/kg, with an average value of about 5 mg/kg . However, soils in the vicinity of arsenic-rich geological deposits, some mining and smelting sites, or agricultural sites where arsenic pesticides were applied, may contain high levels of arsenic.
Arsenic is recognized as a human carcinogen by the U. S. Department of Health and Human Services (DHHS) and the World Health Organization's (WHO) International Agency for Research on Cancer (IARC). The EPA also classifies arsenic as a human carcinogen .
ATSDR has developed a chronic oral MRL of 0.0003 mg/kg/day for noncancerous health effects based on epidemiologic studies that demonstrate skin lesions in people exposed to arsenic. If the children (58 kg) were to be exposed to arsenic in the scenario described above at the maximum soil concentration (9.3 mg/kg), then the estimated exposure dose would be 1.49 x10-6 mg/kg/day. This is about 200 times lower than ATSDR's chronic oral MRL. If adults were to be exposed to arsenic, then the estimated oral exposure dose would be 6.19 x 10-7 mg/kg/day. This is about 485 times lower than ATSDR's chronic MRL. Therefore, exposure to arsenic for the scenario described above is not likely to cause any non-cancerous adverse health effects either for children or adults.
In order to evaluate the possible cancer risk associated with ingestion of arsenic-contaminated soil, we calculated the theoretical cancer risk using EPA's CSF of (1.5 mg/kg/day)-1 for arsenic. PADOH evaluated the cancer risk associated with exposure to arsenic for a lifetime (i.e., 70 years) at 9.28 x 10-7, or a likely increase of about 9 cancers in 10 million people. For the corresponding cancer risk associated with exposure to arsenic for 5 years in this scenario, the risk is very much lower (a likely increase of about 7 cancers in 100 million people). The cancer estimate was calculated using conservative assumptions about frequency and duration of site use previously stated. It is unlikely, however, that a person will be in contact with the highest level of arsenic contaminated soil over an entire 5 years, even if the child plays on the site every day. On the basis of existing data, it appears that the current levels of arsenic do not pose a significant health threat to the people visiting the site because the estimated cancer risk is very insignificant. However, since arsenic is a human carcinogen, exposure to it should be eliminated or reduced to the lowest level possible.
As indicated in the assumption, trespassers who are primarily children (58 kg) playing in the area may have been exposed to lead in surface soil. Those people have been exposed to lead mainly through ingestion and to a lesser degree through inhalation of airborne particulates. Dermal contact is not a significant route of exposure for lead because lead is not readily absorbed through the skin . Moreover, inhalation of fugitive dust is not likely to contribute significantly to the hazard presented by ingestion of soil.
The maximum concentration of lead in on-site surface soil is 1,070 mg/kg (range = 22 mg/kg - 1,070 mg/kg). Because of the high levels of lead in on-site surface soil, lead exposure is of public health concern at the site. Generally, blood lead level rises 3-7 ug/dL for every 1,000 mg/kg increases in soil or dust concentration . Regular contact with 1,070 mg/kg of lead in soil may therefore result in an increase in blood lead levels at a concentration of about 3-7 ug/dL. This level of lead in the soil is less likely to raise a child's blood lead level above the CDC's level of concern of 10 ug/dL. As stated previously, it is estimated that there is only a total of 17 days/year of exposure to the soil contaminants, i.e. there is no regular contact to the soil. Based on this assessment, DOH concludes that exposure to maximum detected level in soil is not likely to result in elevated blood lead level that could cause health problems.
PAHs are a group of chemicals that are formed during the incomplete burning of coal, oil, gas, wood, garbage, or other organic substances, such as tobacco and charbroiled meat. There are more than 100 different PAHs . Studies in animals have also shown that these chemicals can cause harmful effects on skin, body fluids, and the body's system for fighting disease after both short- and long-term exposure. These effects have not been reported in people.
The health effects of individual PAHs are not exactly alike . Although the total PAH concentration was detected at the range of 4.6 mg/kg to108.5 mg/kg, benzo[a]pyrene is the most potent PAH detected on site. It is found at the concentration range of 0.4 mg/kg to 8.2 mg/kg. The PADEP's current residential clean-up standard for benzo(a)pyrene is 2.5 mg/kg, and the nonresidential clean-up standard is 11.0 mg/kg.
ATSDR has not developed a chronic oral MRL for benzo[a]pyrene . However, the estimated oral exposure dose to benzo[a]pyrene through this environmental medium is several thousand time lower than the established NOAEL in animal studies . Therefore, exposure to benzo[a]pyrene for the scenario described above is not likely to cause any noncancerous adverse health effects either for children or adults.
Using the CSF of 7.3 (mg/kg/day)-1 for benzo[a]pyrene that EPA has established, PADOH used the CSF to evaluate an increased cancer risk for this chemical. PADOH evaluated the cancer risk associated with exposure to benzo[a]pyrene for a lifetime (i.e., 70 years) at 3.98 x 10-6, or a likely increase of about 4 cancers in 1 million people. For the corresponding cancer risk associated with exposure to benzo[a]pyrene for 5 years in this scenario, the risk is very much lower (a likely increase of about 3 cancers in 10 million people). These calculated risks based on animal exposure studies  are theoretical and tend to overestimate the risk associated with past exposure to benzo[a]pyrene. Based upon existing data, it appears that the current levels of benzo[a]pyrene do not pose a significant health threat to the people visiting the site because the estimated cancer risk is very insignificant.
Asbestos is the name given to a group of six different fibrous minerals (amosite, chrysotile, crocidolite, and the fibrous varieties of tremolite, actinolite, and anthophyllite) that occur naturally in the environment. Asbestos fibers can enter the air or water from the breakdown of natural deposits and manufactured asbestos products. These fibers do not evaporate into air nor dissolve in water, they are generally not broken down to other compounds, and they will remain virtually unchanged over long periods .
The DHHS, the WHO, and the EPA have determined that asbestos is a human carcinogen. It is known that breathing asbestos can increase the risk of lung cancer and mesothelioma in people. Studies of workers also suggest that breathing asbestos can increase chances of getting cancer in other parts of the body (stomach, intestines, esophagus, pancreas, and kidneys), but this is less certain.
Four (4) on site surface soil samples (0-12 inches) were tested for asbestos (TP-1, TP-3, TP-5, and TP-8) [Figure 3]. Asbestos was detected from only one on-site surface soil sample (0-12 inches) which was taken from area TP-8. The maximum concentration detected was 3.13 million structures per gram (of asbestos fibers greater than 10 micrometers in length).
While no level of airborne asbestos is considered completely safe, there are no levels which were tested at urban background levels at the site. Based on current data and current on-site activities, however, generation of lots of dust on site is unlikely, and it appears that inhalational exposure to asbestos is not a problem. Should the site be developed in the future in a manner that could disturb the asbestos-containing soil, then the greater probability of exposure to asbestos must be taken into consideration.
ATSDR and PADOH recognize that children are especially sensitive when exposed to many contaminants. This sensitivity is a result of the following factors: (1) children are more likely to be exposed to certain media (e.g., soil, sediment, air, surface water or water from springs) because they play outdoors; (2) children are shorter than adults, which means they can breathe dust, soil, and vapors close to the ground; and (3) children are smaller, therefore childhood exposure results in higher doses of chemicals per body weight. Children can sustain permanent damage if these factors lead to toxic exposure during critical growth stages. ATSDR is committed to evaluating their special interest at sites such as the Pathan Chemical Site, as part of ATSDR's Child Health Initiative.
ATSDR and PADOH evaluated the likelihood that children living near the site may have been or may be exposed to contaminants at levels of health concern as a result of playing on site.
The interpretation, advice, and recommendations provided in this HC are based on the preliminary information currently available. Additional information may alter the conclusions and recommendations of this HC. In addition, the conclusions and recommendations of this HC are specific to the Pathan Chemical Site. They should not be considered applicable to any other situations or sites.
PADOH and ATSDR conclude that the site currently poses an indeterminate health hazard. This conclusion is based on the lack of 0-3" of soil samples data and the lack of ambient air monitoring data at the site to determine if nearby residents are exposed to chemicals at levels of public health concerns. Although the limited available data do not indicate an immediate health threat, the data are not adequate to make a definitive health call.
- Sample the soil for hazardous chemicals at a depth of 0-3 inches.
- Conduct ambient air monitoring on site and off site to determine if nearby residents are exposed to asbestos fibers in ambient air at levels of public health concerns.
- If site is developed in a manner that could disturb the soil, dust suppression technique is highly recommended.
- ATSDR and PADOH will ensure that the City of Philadelphia and USEPA are aware of the findings of this consultation.
- ATSDR and PADOH will provide additional health consultation assistance to the City and USEPA. If requested, such assistance could include reviewing sampling plans, new data, and evaluating public health impact.
- Federal On-Scene Coordinator's After Action Report for Pathan Chemical Restart, Philadelphia, PA, 3 November 1998 through 14 December 1998.
- Electronic mail to Thomas Fox, City of Philadelphia Parks and Recreation Director and Kendall O. Banks, City of Philadelphia Risk Assessment, from Robert Lausch, EPA Region III, October 22, 2001.
- Field Trip Report of Pathan Chemical Site, USEPA Region 3, November 2001.
- Agency for Toxic Substance and Disease Registry (ATSDR). Soil/Water/Air Comparison Values and Health Guideline Comparison Values, 06/30/01.
- Data validation reports for Pathan Chemical Site from Fredrick Foreman, Region III ESAT RPO (3ES22), August 17, 2001, September 4, 2001, and September 19, 2001.
- Agency for Toxic Substances and Disease Registry. Toxicological profile for arsenic. Available from: URL: http://www.atsdr.cdc.gov/toxprofiles/tp2.html. Atlanta: US Department of Health and Human Services; 2000.
- Agency for Toxic Substances and Disease Registry. Public health statement for arsenic. Available from: URL: http://www.atsdr.cdc.gov/toxprofiles/phs2.html. Atlanta: US Department of Health and Human Services; 2000.
- U.S. Department of Health and Human Services/Public Health Services/Center for Disease Control. Preventing Lead Poisoning in Young Children, October 1991.
- Agency for Toxic Substances and Disease Registry (ATSDR). Analysis Paper: Impact of Lead-Contaminated Soil on Public Health. U.S. Department of Health and Human Services, Public Health Service, Atlanta, Georgia, May 1992.
- Agency for Toxic Substances and Disease Registry. Toxicological profile for polycyclic aromatic hydrocarbons. Available from: URL: http://www.atsdr.cdc.gov/toxprofiles/tp2.html. Atlanta: US Department of Health and Human Services; 1995.
- Agency for Toxic Substances and Disease Registry. Public health statement for Polycyclic aromatic hydrocarbons. Available from: URL: http://www.atsdr.cdc.gov/toxprofiles/phs2.html. Atlanta: US Department of Health and Human Services; 1995.
- Agency for Toxic Substances and Disease Registry. ToxFAQs for asbestos. Available from: URL: http://www.atsdr.cdc.gov/tfacts69.html. Atlanta: US Department of Health and Human Services; 2001.
- Agency for Toxic Substances and Disease Registry. Public health statement for asbestos. Available from: URL: http://www.atsdr.cdc.gov/toxprofiles/phs2.html. Atlanta: US Department of Health and Human Services; 2001.
Geroncio C. Fajardo, MD, MBA, MS
Pennsylvania Department of Health
This Health Consultation for the Pathan Chemical Site was prepared by the Pennsylvania Department of Health under a cooperative agreement with the federal Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the health consultation was initiated.
Technical Project Officer, SPS, SSAB, DHAC
The Division of Health Assessment and Consultation (DHAC), ATSDR, has reviewed this health consultation and concurs with its findings.
Richard E. Gillig
Section Chief, SPS, SSAB, DHAC, ATSDR
|Contaminant||Environmental Media||Number of Samples||Concentrations Detected*||Comparison Value||Source|
|8||22 ppm - 1,070 ppm||1,000 ppm||CDC,1992**|
|8||3.3 ppm - 9.3 ppm||0.5 ppm||CREG|
|8||4.6 ppm - 108.5 ppm||NA||NA|
|8||0.4 ppm - 8.2 ppm||0.1 ppm||CREG|
|8||3.13 million structures/gram||NA||NA|
* EPA Office of Analytical Services and Quality Assurance, Environmental Science Center, Fort Meade, MD 20755-5350, August 17, August 28, and September 4, 2001
** Analysis Paper: Impact of Lead-Contaminated Soil on Public Health, ATSDR, May 1992.
ppm = parts per million = (this is the same as milligrams/kilogram
NA = Not Available
CREG = Cancer Risk Evaluation Guide