BIG BEAVER FALLS SCHOOL SITE
BEAVER FALLS, BEAVER COUNTY, PENNSYLVANIA
The Pennsylvania Department of Environmental Protection (PADEP) asked the PennsylvaniaDepartment of Health (PADOH) and the Agency for Toxic Substances and Disease Registry(ATSDR) to evaluate preliminary environmental data from the Big Beaver Falls School Site (site)and determine if the site poses a health hazard to students, faculty, and visitors. Lead, arsenic,antimony, and benzo(a)pyrene were detected in surface soil (0-2 feet) at maximum concentrations of2,540 milligrams per kilogram (mg/kg), 237 mg/kg, 36.4 mg/kg, and 3.2 mg/kg, respectively. Thereis no exposure to contaminated groundwater beneath the site. The site is used for outdoor athleticfield events (practices) and receives occasional visitors from the community.
Based upon preliminary data, the site does not appear to pose a public health threat to students,faculty, visitors, and the community at large under a school use scenario of 180 days per year. Overthe next few years, the school district plans to make certain improvements to the property, includingfilling and regrading the site with clean soil to construct new baseball and football fields. Ifcompleted, that action will reduce or eliminate future exposure to contaminated soil on the site.
The Big Beaver Falls School Site is on 8th Avenue at 16th Street adjacent to the Big Beaver HighSchool in Beaver Falls, Pennsylvania (Figures 1 and 2). The 30- acre site consists of severalproperties the school district wishes to improve or expand, including the former elementary school,the middle school, and high school athletic fields (Figure 3). The site is bounded by residential andindustrial development to the north, east and south, and a creek (Walnut Bottom Run) and railroadtracks to the west (Figure 3). According to the 2000 census, Beaver Falls has a population of 9,920. The schools have a combined total enrollment of 1,291 students, and the schools and the rest ofthe town are served by a state approved public water supply.
From the early 1900s to the late 1970s, the site was used by the school as well as a variety ofindustrial enterprises. Some included a chemical company (acid works), an asbestos protected metalcompany, a septic tank company, a scrap yard, and a drilling company (Figure 4). Since thecompletion of the new high school in the 1980s, the site has been used only by the school andoccasional site visitors. The past industrial uses have contaminated on-site soil and groundwater, andnow there is a potential exposure risk to students and others, particularly through the soil where theproposed football field is to be constructed in the southwestern portion of the site (Figure 4).
As part of the school's expansion project, the former elementary school building, now empty, will bestructurally connected to the middle school and renovated for future occupancy. According toPADEP, the best estimate of a time frame for project completion, is two to three years. Thecontractor inadvertently discovered contaminated surface (0-2 feet) soil (lead to 2,540 mg/kg, arsenicto 237 mg/kg, antimony to 36.4 mg/kg, benzo(a)pyrene to 3.2 mg/kg) when, as part of the general(Phase 2) site investigation, he was trying to determine potential hazards to work crews. Reportedcontaminant levels are based on a preliminary, non-comprehensive soil sampling effort. Still, surfacesoil does not appear to be contaminated at levels of health concern over the entire site. Soil wascollected in discrete, 2-foot composite samples at each sampling point. Lead, for example, wasdetected in only 2 of the 11 samples (SB-11 and SB-13, Figure 4), and benzo(a)pyrene in only one. SB-11 and SB-13 (where the highest arsenic concentration was detected) are outside the boundariesof both proposed playing fields. The proposed football field site and the land immediatelysurrounding it (Figure 4) have been owned and used by the school district since construction of themiddle school over 65 years ago. Therefore, an exposure risk from recreational use may have existedthere (apparently unknown to anyone) for that entire time. Students from kindergarten through grade12 use the property during the months when school is in session. Currently the field is used forsoccer, football, and other practices, but not for officially scheduled games.
Given the above circumstances, the PADEP asked ATSDR and PADOH to evaluate the site anddetermine if the intended use poses a health hazard to students, faculty, and occasional site visitors.
On October 11 and 12, 2001, J. E. Godfrey of PADOH visited the site, the latter visit with a PADEPrepresentative. On October 11 (afternoon), the athletic fields were buzzing with activity and a fulldress football practice was underway. The perimeter of the practice field is bounded by an 8-foot highchain link fence, but it is breached in at least one place along the west (back) side and provides noreal security.
On the morning of October 12, the PADEP representative pointed out monitoring well and soilboring locations. The present topsoil is only a few inches thick, and in some places the subsurface fillmaterial (concrete, rocks, and stumps) is directly exposed. The school district plans to fill and gradethe area with clean topsoil so that new baseball and football fields can be constructed (Figure 4). That action will lessen or remove the current risk of exposure to lead, arsenic, and other contaminantsin the existing surface soil. Because no one consumes or bathes in the groundwater beneath the site,heavy metal contamination in that medium (e.g. cadmium at 494 micrograms/liter (µg/L) is not a health concern and will not be discussed in this document.
In this section, PADOH discusses the effects that may occur in persons exposed to site-relatedcontaminants. The ATSDR has developed health-based comparison values (CVs) that are chemical-specific concentrations, which determine environmental contaminants of health concern. We use CVsto determine which contaminants require further evaluation. These CVs include EnvironmentalMedia Evaluation Guides (EMEGs), and Reference Dose Media Evaluation Guides (RMEGs) fornoncancerous health effects. If environmental media guides cannot be established because of a lackof available health data, other CVs, such as those from the U.S. Environmental Protection Agency(EPA), may be used to select a contaminant for further evaluation. While media concentrations lessthan a CV are unlikely to pose a health threat, media concentrations above a CV do not necessarilyrepresent a health threat. Therefore, CVs should not be used as predictors of adverse health effects or for setting cleanup levels.
Lead was detected in only 2 out of 11 surface soil samples tested on the site. Lead levels in thosesamples (2,540 mg/kg, 1,620 mg/kg) were above the 400 mg/kg screening level used by EPA. Toproperly assess the human health threat associated with exposure to contaminated soil, it is importantto have the shallow surface soil (0-3 inches) data. Since we do not have that data, we will use themaximum level of lead detected in the 0-2 feet interval, e.g., 2,540 mg/kg.
Although lead is a concern for adults, children are particularly susceptible to adverse health effectsfrom lead exposure. Present scientific information suggests that blood lead levels of 10 to 25micrograms per deciliter (ug/dL) may be related to delayed mental development, reduced intelligentquotient (IQ) scores, impaired hearing, and poor attention span.
To determine if the levels of lead are a concern at this site, we evaluated the potential exposure basedon a recreational use scenario. We assumed that students are on the field for two hours per day, 180days per year for 13 years. PADOH calculated a conservative oral reference dose estimate thatcorresponds to a residential exposure to 400 mg/kg of lead in soil, and using that as a screeningvalue, compared it to potential recreational oral exposure. Dermal exposure and inhalation offugitive dust are unlikely to contribute significantly to the hazard represented by ingestion of soil.
The estimated exposure for a child (15 kg) under the above described scenario is 0.00139 mg/kg/day. This is about 3.6 times lower than the level considered protective of public health. The estimatedexposure for an adult (70 kg) is 0.000149 mg/kg/day. This is also about 3.6 times lower than thelevel considered protective of public health. The level of lead in the soil from preliminary samplingdata, therefore, does not appear to pose a public health threat for the intended use of the site.
In general, the concentration of arsenic in soil varies widely across the United States, ranging fromabout 1 to 40 mg/kg, with an average value of about 5 mg/kg (4). At the site, arsenic is alsovariable, from a low of 12.5 mg/kg to a high of 237 mg/kg (Figure 4). However, soils near arsenic-rich geological deposits, some mining and smelting sites, or agricultural sites where arsenic pesticideswere applied, may contain higher levels of arsenic.
Skin lesions appear to be the earliest observable sign of chronic exposure to arsenic (4). Arsenic isrecognized as a human carcinogen by the U. S. Department of Health and Human Services and theWorld Health Organization's International Agency for Research on Cancer. The EPA also classifiesarsenic as a human carcinogen.
ATSDR has developed a chronic oral minimal risk level (MRL) of 0.0003 mg/kg/day for non-cancerous health effects based on epidemiologic studies that demonstrate skin lesions in peopleexposed to arsenic. Doses below the MRL are not likely to cause any non-cancerous adverse healtheffects. Doses above the MRL require further evaluation to determine if adverse effects are likely tooccur.
If children (15 kg) were to be exposed to arsenic in the school scenario described above at themaximum soil concentration (237 mg/kg), then the estimated exposure dose would be 0.000129mg/kg/day, which is about 2.3 times lower than ATSDR's chronic oral MRL. If adults were to beexposed to arsenic, then the estimated oral exposure dose would be 0.0000139 mg/kg/day, which isabout 22 times lower than ATSDR's chronic MRL. Therefore, exposure to arsenic for a school usescenario is unlikely to cause any non-cancerous adverse health effects either for children or adults.
To evaluate the possible cancer risk associated with ingestion of arsenic contaminated soil, wecalculated the theoretical cancer risk using EPA's Cancer Slope Factor (CSF) of 1.5 (mg/kg/day) -1for arsenic. PADOH evaluated the cancer risk associated with exposure to arsenic for 13 years at3.8x10-6, or a likely increase of about 4 cancers in 1,000,000 people. The cancer estimate wascalculated 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 contaminatedsoil over an entire school career, even if he plays on the site every school day. Based upon existingdata, it appears that the current levels of arsenic do not pose a significant health threat for recreationaluse of the site. However, because arsenic is a human carcinogen, exposure to it should be eliminatedor reduced to the lowest level possible.
Antimony concentrations were not above any CVs, so that chemical will not be discussed further.
Benzo(a)pyrene (B[a]P) was detected in only one soil sample at a maximum concentration of 3.5mg/kg. B(a)P is a member of a group of chemicals known as polycyclic aromatic hydrocarbons(PAHs). PAHs are formed during the incomplete burning of coal, oil, garbage or other organicsubstances.
In humans, non-cancerous health effects that may result from eating or drinking foods containing lowlevels of B(a)P are unknown. ATSDR has not developed an MRL and EPA has not developed areference dose. Existing studies in animals suggest that exposure doses at very high levels (severalorders of magnitude above those at the site) are necessary to cause non-cancerous adverse healtheffects. Therefore, the level found in only one sample on site is unlikely to cause such effects.
B(a)P is classified as a probable human carcinogen by EPA, the Department of Health and HumanServices, and the International Agency for Research on Cancer. If people ingest soil contaminatedwith B(a)P at 3.5 mg/kg under the school use scenario previously stated, there will be no significant increased cancer risk.
ATSDR and PADOH recognize that infants and children may be more sensitive to exposures than adults in communities with contamination in water, soil, air, or food. This sensitivity is a result of a number of factors. Children are more likely to be exposed because they play outdoors and they often bring food into contaminated areas. Children are shorter than adults, which means they breathe dust, soil, and heavy vapors close to the ground. Children are also smaller, resulting in higher doses of chemical exposure per body weight. The developing body systems of children can sustain permanent damage if toxic exposures occur during critical growth stages. Most importantly, children depend completely on adults for risk identification and management decisions, housing decisions, and access to medical care. Therefore, ATSDR and PADOH are committed to the special interests of children, and have evaluated child-specific scenarios at the Big Beaver Falls School Site.
Based upon the site preliminary data submitted for review, PADOH and ATSDR conclude that thesite poses no apparent public health hazard to students, faculty, and occasional site visitors under aschool use scenario of 2 hours per day for 180 days per year for 13 years. The school district plans tofill and grade the practice fields with clean soil which, if accomplished, will reduce or eliminate existing risks of exposure to contaminated soil.
Sample the on-site soil for hazardous chemicals at a depth of 0 to 3 inches. At PADEP's request,PADOH and ATSDR will evaluate those samples to make a final determination as to whether the site poses a health hazard through that medium.
The PADEP and PADOH will present the conclusions of this health consultation to the Big Beaver School District Administration. Should the Administration request it, PADEP and PADOH will present the conclusions to the community at large in an appropriate format, such as a public meeting or through printed materials.
1. United States Census Bureau. Census 2000.
2. Pennsylvania Department of Environmental Protection. August, 2001. Site Investigation Report, Big Beaver Falls School District, Beaver Falls, Beaver County, Pennsylvania.
3. Commonwealth of Pennsylvania. 1995. Land Recycling and Environmental RemediationStandards Act (Act 2).
4. Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Arsenic (Update), U.S. Public Health Service. Atlanta, Georgia: ATSDR, September 2000.
J. E. Godfrey, P.G.
Licensed Professional Geologist
Pennsylvania Department of health
This Health Consultation for the Big Beaver Schools Site was prepared by the Pennsylvania Department of Health (PADOH) 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.
Lisa C. Hayes
for Richard E. Gillig
SectionChief, SPS, SSAB, DHAC, ATSDR