HEALTH CONSULTATION
HETZELL PLAYGROUND 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 Hetzell Playground Site. ATSDR and PADOH were requested to review the most recent EPA sampling at the site and to evaluate the preliminary data to determine if the site poses a public health hazard.
The chemicals of health concern selected for evaluation include arsenic, dieldrin, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs); they were detected in surface soil (0-12 inches) at maximum concentrations of 10.5 milligrams per kilogram (mg/kg), 0.045 mg/kg, 3.99 mg/kg, and 1.6 mg/kg, respectively. Additional testing of surface soil samples (0-3 inches) was conducted for PCBs. The maximum levels detected were: 1.5 mg/kg of Aroclor-1254 and 1.6 mg/kg of Aroclor-1260.
On the basis of existing preliminary data, ATSDR and PADOH conclude that the site currently poses no apparent public health hazard.
BACKGROUND AND STATEMENT OF ISSUES
Site History
The Hetzell Playground Site (the site), which is approximately 268 feet by 300 feet, is located in a residential area in Philadelphia, Pennsylvania (Figure 1 and Figure 2). It is bounded by Columbia Avenue and residential homes to the southwest, Thompson Street and residential homes to the southeast, Livingston Street and residential homes to the northwest, and Earl Street and Adaire Public School to the northeast (Figure 3).
The city of Philadelphia currently owns this property [1]. Sometime in 1975-1976, general construction, electrical, and plumbing contracts were awarded for a project at the facility. In 1983, an electrical switch box was scheduled to be re-installed and the system placed on timers within the next several weeks. There were also histories of electrical-related works on site in the 1990s. A pile of dirt reportedly is placed on site every year as a filling material for the playground [2]. While it is not the objective of this HC to determine the source of contamination, it is possible that the past electrical-related works on site and the dirt added on the playground every year could have contributed to the detected levels of chemicals of health concern, especially the PCBs.
The site is currently surrounded by an iron fence and consists of a soccer field and a baseball field. Since the completion of the playground in 1954, the site has been used by the school and other residents in the community. Students from kindergarten through grade 8 use the property during all months when school is in session.
Site Visit
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 Department of Finance–Division of Risk Assessment conducted a site visit. According to the EPA Region 3 official, the playground's appearance was similar to that observed in July 2001, except that there was evidence of recent recreational activity (soccer) and an increased area of bare ground, which probably occurred during the soccer matches [3]. The site does not appear to be well vegetated.
Site Contamination
In July 2001, EPA Region 3 tested two soil samples taken from the Hetzell Playground. The samples were analyzed for the full scan of inorganics (metals and cyanide) and organics (volatiles, semi-volatiles, pesticides and PCBs) [4]. Table 1 shows only the chemicals of health concern that were detected in various surface soil samples (0-12 inches deep) collected from the site in July.
On October 31, 2001, and November 1, 2001, Urban Engineers, Inc. (Urban), conducted additional soil sampling at the site as per the city of Philadelphia Risk Management Division's request. Twenty-nine (29) samples were analyzed for PCBs (EPA Method 8082) by GLA Laboratories, Inc. The objective of the investigation was to characterize the extent of the PCBs present within the surface soil. The sampling strategy was developed with the assistance of EPA Region 3 and the city of Philadelphia Risk Management Division. The majority of the samples analyzed (25 out of 29) were surface soil samples (collected at 0 to 3 inches deep); the other samples were collected at a depth of 12 inches. Analytical results, along with information related to sampling depths and number of samples analyzed, are summarized in Table 2 [5].
Of the seven Aroclor mixtures tested (Aroclor-1016, Aroclor-1221, Aroclor-1232, Aroclor-1242, Aroclor-1248, Aroclor-1254, and Aroclor-1260), only two (Aroclor-1254 and Aroclor-1260) were detected in soil. Spatial distribution of detected Aroclor-1254 and Aroclor-1260 in surface soils are presented on Figures 4 and 5, respectively. These data were used in evaluating the public health threat concerns as a result of the exposure to these PCBs.
Currently, the site is used as a playground by the students of Adaire Public School and the residents around the area. The primary public health issue that needs to be evaluated is the exposure to the chemicals of health concern at 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 [6]. 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 and 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 1 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 originating from hazardous waste sites.
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 for all of the chemicals of health concern other than for the PCBs analyzed by GLA Laboratories, Inc., at this time, we will use the maximum levels for the other chemicals of health concern (arsenic, dieldrin, and benzo[a]pyrene) from soil samples tested by Tetra Tech, Inc. (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 because the contaminants could be diluted with more 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 at this site). Therefore, the 0-12 inches of soil concentration of a specific chemical could underestimate the amount of the chemical in the top 0-3 inches of surface soil.
PADOH considered the worst-case scenarios for exposures of children playing on site through ingestion of soil for a total exposure duration of 10 years at the maximum levels of the contaminant detected. Dermal exposure and inhalation of fugitive dust particles are not likely to contribute significantly to the hazard represented by ingestion of soil. To evaluate for noncarcinogenic health effects, the assumption in this case involves children with an average weight of 20 kg and who would have been playing for 4 hours per day for 5 days a week for 12 weeks during summer months and who also would have been playing for 4 hours per day for 2 days a week (on weekends) for the rest of the school year, which totals 40 weeks. 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 at 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 [6]. To evaluate for carcinogenic health effects using the CSFs, the assumption in this case uses an average weight of 40 kg for bigger children.
Arsenic
As indicated, people who visited the site (especially children playing there) 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 [7].
Arsenic was detected in two soil samples (0-12 inches); levels ranged from 7.8 mg/kg to 10.5 mg/kg. 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 (10.5 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 [8]. However, soils in the vicinity of arsenic-rich geological deposits, some mining and smelting sites, or agricultural sites where arsenic pesticides were applied, might 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 International Agency for Research on Cancer (IARC). 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 [6]. If the children (20 kg) were to be exposed to arsenic in the scenario described above at the maximum soil concentration (10.5 mg/kg), then the estimated exposure dose would be about 6.904 x 10-6 mg/kg/day. This is about 40 times lower than ATSDR's chronic oral MRL. If adults were to be exposed to arsenic, then the estimated oral exposure dose would be much lower than that of the children. Therefore, exposure to arsenic for the scenario described above is not likely to cause any noncancerous 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 [6]. PADOH evaluated the cancer risk associated with exposure to arsenic for a lifetime (i.e., 70 years) at 5.2 x 10-6, or a likely increase of about 5 cancers in 1 million people. For the corresponding cancer risk associated with exposure to arsenic for 10 years, the risk is very much lower (a likely increase of about 7 cancers in 10 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 10 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 increase in cancer risk is insignificant.
Dieldrin
Dieldrin is an insecticide that binds tightly to soil and breaks down very slowly [9]. The IARC has determined that dieldrin is not classifiable as to its carcinogenicity to humans while EPA has determined that dieldrin is a probable human carcinogen [10].
Dieldrin was detected in two soil samples (0-12 inches); levels ranged from 0.025 mg/kg to 0.045 mg/kg. These levels are lower than the PADEP's current Act 2 residential clean-up standard for dieldrin of 1.1 mg/kg and a nonresidential standard of 5.0 mg/kg. As stated earlier, proper evaluation of the public health threat requires data from shallow (0-3 inches) soil. In the absence of that data and to estimate the exposure dose, we have used the maximum dieldrin contamination level (0.045 mg/kg) obtained from the 0-12 inches of surface soil samples.
ATSDR has developed a chronic oral MRL of 0.00005 mg/kg/day for noncancerous health effects [6]. If the children (20 kg) were to be exposed to dieldrin in the scenario described above at the maximum soil concentration (0.045 mg/kg), then the estimated exposure dose would be about 2.959 x 10-8 mg/kg/day. This is about 1,600 times lower than ATSDR's chronic oral MRL. If adults were to be exposed to dieldrin, then the estimated oral exposure dose would be much lower than that of the children. Therefore, exposure to dieldrin for the scenario described above is not likely to cause any noncancerous adverse health effects either for children or adults.
EPA has established a CSF of 16 (mg/kg/day)-1 for dieldrin [6]. PADOH used the CSF for this chemical to evaluate an increased cancer risk for bigger children weighing 40 kg. Based on the theoretical cancer risk estimation for an exposure period of 10 years and the assumptions enumerated previously, the predicted cancer occurrence would be about 3 additional cancers per 100 million people. These calculated risks based on animal exposure studies are theoretical and tend to overestimate the risk associated with past exposure to dieldrin. On the basis of existing data, it appears that the current levels of dieldrin do not pose a significant health threat to the people visiting the site because the estimated increase in cancer risk is insignificant.
Polycyclic Aromatic Hydrocarbons (PAHs)
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 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 [11].
The health effects of individual PAHs are not exactly alike [12]. The total PAH concentrations detected ranged from 2.10 mg/kg to 3.99 mg/kg. However, benzo[a]pyrene, the most potent PAH detected on site, was found at concentrations ranging from 0.17 mg/kg to 0.31 mg/kg. These values are much lower than the PADEP's current residential clean-up standard for benzo[a]pyrene (2.5 mg/kg) and the nonresidential clean-up standard (11.0 mg/kg). The IARC and USEPA have determined that benzo[a]pyrene is probably carcinogenic to humans [12].
ATSDR has not developed a chronic oral MRL for benzo[a]pyrene [6]. However, the estimated oral exposure dose to benzo[a]pyrene through this environmental medium is several thousands lower than the established NOAEL in animal studies [13]. Therefore, exposure to benzo[a]pyrene for the scenario described above is not likely to cause any non-cancerous adverse health effects either for children or adults.
USEPA has established a CSF of 7.3 (mg/kg/day)-1 for benzo[a]pyrene [6]. PADOH used the CSF to evaluate the cancer risk associated with exposure to benzo[a]pyrene for a lifetime (i.e., 70 years) at 7.44 x 10-7, or a likely increase of about 7 cancers in 10 million people. For the corresponding cancer risk associated with exposure to benzo[a]pyrene for 10 years, the risk is lower (a likely increase of about 1 cancer in 10 million people). These calculated risks based on animal exposure studies are theoretical and tend to overestimate the risk associated with 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 increase in cancer risk is insignificant.
Polychlorinated Biphenyls (PCBs)
PCBs are a group of synthetic organic chemicals that contain 209 individual chlorinated biphenyl compounds (known as congeners) with varying harmful effects. On the basis of the evidence for cancer in animals, the Department of Health and Human Services (DHHS) has stated that PCBs might reasonably be anticipated to be carcinogens. EPA and the IARC have determined that PCBs are probably carcinogenic to humans [14].
Aroclor-1254 and Aroclor-1260 were detected in 25 soil samples (0-3 inches). Aroclor-1254 levels ranged from 0.077 mg/kg to 1.5 mg/kg while Aroclor-1260 levels ranged from 0.051 mg/kg to 1.6 mg/kg. Combining the two levels results in a total PCB level of 0.128 mg/kg to 3.1 mg/kg. These levels are below the PADEP Act 2 clean-up standards. PADEP has established under Act 2 a residential clean-up standard for Aroclor-1254 of 4.4 mg/kg and a nonresidential standard of 44 mg/kg as well as a residential clean-up standard for Aroclor-1260 of 30 mg/kg and a nonresidential standard of 130 mg/kg.
ATSDR has developed a chronic oral MRL of 0.00002 mg/kg/day for non-cancerous health effects of Aroclor-1254 [6]. If the children (20 kg) were to be exposed to this chemical at the maximum soil concentration (1.5 mg/kg), then the estimated exposure dose would be about 20 times lower than ATSDR's chronic oral MRL. If adults were to be exposed to this chemical, then the estimated oral exposure dose would be much lower than that of the children.
Although ATSDR has not established MRLs for Aroclor-1260, exposure to Aroclor-1260 through this environmental medium at the maximum soil concentration (1.6 mg/kg) is not expected to cause any health problem since the estimated oral exposure dose is several thousand times lower than the NOAELs for non-carcinogenic health effects observed in animal studies [15]. Therefore, exposure to PCBs for the scenario described above is not likely to cause any non-cancerous adverse health effects either for children or adults.
Using the upper-bound CSF of 2.0 (mg/kg/day)-1 for high risk and persistence environmental PCBs like Aroclor-1254 and Aroclor-1260 [16], PADOH estimated the cancer risk for the total PCBs detected on site (i.e., Aroclor-1254 plus Aroclor-1260). The estimated cancer risk associated with exposure to total PCBs for a lifetime (i.e., 70 years) is 2.038 x 10-6, or a likely increase of about 2 cancers in 1 million people. For the corresponding cancer risk associated with exposure to total PCB for 10 years, 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 total PCBs. On the basis of existing data, it appears that the current levels of total PCBs do not pose a significant health threat to the people visiting the site because the estimated cancer risk is very insignificant.
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 Hetzell Playground Site, as part of ATSDR's Child Health Initiative.
ATSDR and PADOH evaluated the likelihood that children playing on the playground might have been or might be exposed to contaminants at levels of health concern as a result of playing on site. Although the levels of chemicals of health concern are low, it is a prudent public health activity to discourage children from ingesting soil particles in the course of playing games.
The interpretation, advice, and recommendations provided in this HC are based on the preliminary information currently available. Additional information might alter the conclusions and recommendations of this HC. In addition, the conclusions and recommendations of this HC are specific to the Hetzell Playground Site. They should not be considered applicable to any other situations or sites.
On the basis of the preliminary data, we conclude that the site currently poses no apparent public health hazard. However, collecting true surface soil samples (0-3 inches) will allow for a more definitive health call.
. Washington DC: US Environmental
Protection Agency; 2001.. Washington DC: US Environmental Protection
Agency; 2001.Geroncio C. Fajardo, MD, MBA, MS
Epidemiologist
Pennsylvania Department of Health
This health consultation for the Hetzell Playground 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.
Roberta Erlwein
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.
Lisa C. Hayes
for Richard E. Gillig
Section Chief, SPS, SSAB, DHAC, ATSDR
Figure 3. Site Location Map/Development Plan
Figure 4. PCB Soil Sampling Plots (Aroclor-1254 Concentrations, ppb)
Figure 5. PCB Soil Sampling Plots (Aroclor-1260 Concentrations, ppb)
Table 1. Hetzell Playground Site Contaminants of Health Concern
| Contaminant | Environmental Media |
Number of Samples |
Concentrations Detected* | Comparison Value | Source |
| Arsenic |
Surface soil |
2 |
7.8 ppm–10.5 ppm | 0.5 ppm | CREG |
| Dieldrin | Surface soil (0-12 inches) |
2 | 0.025 ppm–0.045 ppm | 0.04 ppm | CREG |
| PAH (Total PAHs) |
Surface soil (0-12 inches) |
2 | 2.10 ppm–3.99 ppm | NA | NA |
| Benzo[a]pyrene | Surface soil (0-12 inches) |
2 | 0.170 ppm–0.310 ppm | 0.1 ppm | CREG |
| PCB (Aroclor-1260) |
Surface soil (0-12 inches) |
2 | 1.1 ppm–1.6ppm | 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
ppm = parts per million =(this is the same as milligrams/kilogram
or mg/kg)
NA = not available
CREG = cancer risk evaluation guide
Table 2. Hetzell Playground Site PCBs of
Health Concern
| Contaminant | Environmental Media |
Number of Samples |
Concentrations Detected* | Comparison Value | Source |
| Aroclor-1254 |
Surface soil |
25 |
0.077 ppm–1.500 ppm |
1 ppm = |
RMEG Chronic EMEG Chronic Oral MRL |
| Aroclor-1254 |
Surface soil |
4 |
0.15 ppm–0.22 ppm |
1 ppm = |
RMEG Chronic EMEG Chronic Oral MRL |
| Aroclor-1260 | Surface soil (0-3 inches) |
25 | 0.051 ppm–1.600 ppm |
NA |
NA |
| Aroclor-1260 | Surface soil (12 inches) |
4 | 0.16 ppm–0.19 ppm | 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
ppm = parts per million =(this is the same as milligrams/kilogram
or mg/kg)
NA = not available
CREG = cancer risk evaluation guide
