PUBLIC HEALTH ASSESSMENT
POLES, INCORPORATION WOOD TREATMENT FACILITY
OLDTOWN, BONNER COUNTY, IDAHO
Poles, Incorporated (Poles, Inc.) is an active pole peeling and storage treatment facility. It was formerly a pole treating facility utilizing pentachlorophenol as a wood preservative. Poles, Inc. is located in Oldtown, Bonner County, Idaho. The Pend Oreille River borders the northern edge of the site and the Idaho Hill Elementary School (school) borders the southern edge of the site. The Bureau of Environmental Health and Safety, Division of Health, Idaho Department of Health and Welfare reviewed available environmental, toxicological, and epidemiological information and prepared this public health assessment under a cooperative agreement with the federal Agency for Toxic Substances and Disease Registry.
What kind of chemical contamination was found?
Pentachlorophenol, dioxin, furan, and polycyclic aromatic hydrocarbons contamination was found in surface and subsurface soil onsite. This contamination appears to have migrated into groundwater. Pentachlorophenol and polycyclic aromatic hydrocarbons were also detected at low levels in air, sediment in the Pend Oreille River, and offsite surface soils. Dioxins and furans were found in on and offsite surface soils. Pentachlorophenol was not found in school indoor air, and no contaminants were found in school dust wipe samples. Arsenic and other inorganic metals were also detected in soils, sediment, and groundwater both on and off site. Arsenic and other inorganic metals are not known to be site-related contaminants.
What are pentachlorophenol, dioxins, furans, and polycyclic aromatic hydrocarbons?
Pentachlorophenol is a manufactured chemical not naturally found in the environment and is a registered biocide (or pesticide). Pentachlorophenol is used in industry as a wood preservative for power line poles, railroad ties, cross arms, and fence posts. It is no longer allowed for public use at home or for gardening. People are generally exposed to the technical-grade of pentachlorophenol versus the pure form of pentachlorophenol. The technical-grade pentachlorophenol contains impurities such as polychlorinated dibenzo-p-dioxins and dibenzofurans. Polychlorinated dibenzo-p-dioxins are a family of 75 different compounds. These compounds have varying harmful effects. They are produced naturally as well as by human activities such as industrial, municipal and domestic incineration and combustion processes and the manufacture of chlorinated phenols and other chlorinated chemicals like pentachlorophenol. Polychlorinated dibenzofurans are a family of 135 individual compounds with varying harmful health and environmental effects. With very few exceptions, these chemicals are not deliberately produced by industry. The processes that emit the unwanted dibenzofurans are much the same as those that emit dibenzo-p-dioxins. These two chemical families are often found in association with one another and cause similar toxic effects. The individual compounds that comprise the families are called congeners. During the wood treatment process, technical-grade pentachlorophenol is mixed with wood treatment oil that contains polycyclic aromatic hydrocarbons. There are more than 100 different polycyclic aromatic hydrocarbons, which generally occur as complex mixtures. While some polycyclic aromatic hydrocarbons can be formed naturally in the environment, human activities such as burning coal, car exhaust, and tobacco smoke are the major sources of polycyclic aromatic hydrocarbons in the air. Polycyclic aromatic hydrocarbons, as well as pentachlorophenol, can be released during the process of heating the pentachlorophenol and treating oil solution mixtures.
How might I be exposed to chemical contamination from the site?
The Bureau of Environmental Health and Safety evaluated current environmental sampling data from on and off-site. Currently, only onsite surface soils contain elevated levels of pentachlorophenol, polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and several polycyclic aromatic hydrocarbons (contaminants of concern). Workers, trespassers, and children playing at the pole yard may be exposed to chemical contamination from the site. The Bureau of Environmental Health and Safety advises community members to avoid exposure to the contaminated soil by refraining from trespassing on the site. Workers should be careful to limit exposure to onsite soil and to leave work clothes and shoes at work. The Bureau of Environmental Health and Safety did not find site-related chemical concentrations off-site at levels that could be a health risk.
What are the public health implications of exposures to site-related contaminants?
After reviewing available environmental data, current exposure to contaminants in the onsite surface soil at Poles Inc. is categorized by the Bureau of Environmental Health and Safety as a "no apparent public health hazard" as defined by the Agency for Toxic Substances and Disease Registry. Trespassers may be exposed to the contaminated surface soil; however, levels of contaminants to which they are exposed are not expected to cause adverse health effects. Current exposures to all other environmental media (e.g., air, sediment, offsite surface soil, onsite subsurface soil, and indoor dust) do not pose a health hazard. This assessment does not address past exposures to site-related contaminants. The Bureau of Environmental Health and Safety makes recommendations to minimize or eliminate exposures and for continued activity at the site and in the community. Further explanation of the findings can be found in the full report.
Could exposures to chemical contamination at the site cause an increased rate of cancer in the community?
The overall cancer incidence in the combined area of Oldtown and Priest River, Idaho and Newport, Washington between 1992 and 1999 was within the expected range when compared to the remainder of the State of Idaho. However, the Cancer Data Registry of Idaho found an increased rate of sarcoma cancer in the same three ZIP Code area. Sarcoma is a rare type of cancer. There are known medical, environmental, and genetic factors associated with it. Literature suggests that the technical-grade pentachlorophenol that includes impurities may cause one form of sarcoma, called soft tissue sarcoma. Currently, the Bureau of Environmental Health and Safety does not know whether the identified sarcoma cases are related to the past exposures to the Oldtown site but is further investigating the cases in collaboration with the Cancer Data Registry of Idaho.
What are the major recommendations of the public health assessment?
The Bureau of Environmental Health and Safety has made several recommendations for actions to minimize or eliminate possible exposures of the community from site contamination and site physical hazards and to address concerns heard from community members. The key elements are: 1) as a precaution, restrict site access; 2) conduct a well survey for nearby private wells and groundwater monitoring at the site; 3) further investigate the elevated sarcoma cancer rate; and 4) conduct a cancer incidence evaluation for Idaho Hill Elementary School employees.
What are the follow up public health actions that will be taken?
The Environmental Protection Agency (EPA) is in the process of determining the Hazard Ranking Score for Poles, Inc.--this is part of the EPA's Superfund process. The EPA and the Idaho Department of Environmental Quality will be working with the site owner to control contamination. The Cancer Analysis Working Group of Idaho will further investigate the biologically plausible cancer cases possibly linked to site-related exposures for the surrounding communities and the Idaho Hill Elementary school employees. The Bureau of Environmental Health and Safety will provide health education to assist residents in mitigating exposure.
Where can I get more information?
If you have more questions about this public health assessment or want to obtain extra copies of this document, please contact the Bureau of Environmental Health and Safety at 208-334-0606, toll-free 1-866-240-3553, or behs@idhw.state.id.us. If you would like more information on additional site activities, please contact the Idaho Department of Environmental Quality at 208-769-1422 or plyon@deq.state.id.us and/or the Environmental Protection Agency at 206-553-1388 or serrano-velez.lilibeth@epa.gov.
In fall 2000, the United States Environmental Protection Agency (EPA) was petitioned by a concerned citizen and was requested by the Idaho Department of Environmental Quality (IDEQ) to conduct an integrated site assessment for Poles, Incorporated (Poles, Inc.) in Oldtown, Idaho. Poles, Inc. is an active pole peeling facility and formerly treated wood poles with pentachlorophenol (penta), a wood preservative. The Bureau of Environmental Health and Safety (BEHS), Division of Health, Idaho Department of Health and Welfare has a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR) to conduct public health assessments and consultations for hazardous waste sites in Idaho. BEHS completed this public health assessment under this cooperative agreement.
A public health assessment is a tool used to determine if and what kind of activities are needed to protect the health of a community residing/working near a hazardous waste site, and to determine the need for follow-up health activities (e.g., health study). To achieve this goal, this assessment contains three types of evaluations: (1) the identification of pathways of exposure to site contaminants and an evaluation of their public health implications; (2) a summary of relevant and available health outcome data (e.g., cancer registry data); and (3) evaluations of specific community health concerns about the site. The first type of evaluation addresses the contaminants that are present at site above comparison values, the determination of exposure pathways and the potential for those chemicals to enter people's bodies. These evaluations can be found in Sections 4.1 - 4.3 and Sections 5.1, respectively. The evaluation of relevant and available health outcome data can be found in Section 5.2, and the evaluation of community health concerns about the site can be found in Section 5.3.
Poles, Inc. a current pole peeling and storage facility was an active, open-vat, thermal wood treatment facility using penta as a wood preservative. The facility is located within the city limit of Oldtown, just 400 feet south of the Pend Oreille River in the Panhandle of Northern Idaho, Bonner County (Appendix A, Figure A-1).
The site, although in the process of dismantling and decommissioning processes structures,
included a treatment shed, thermal dip tank, office building, garage, boiler building, wood waste
disposal area, peeler, and pole storage yard (Appendix A, Figure A-2). The partially below
ground thermal dip tank was next to the treatment shed which is a fenced, roofed structure with
open sides. The dip tank had covers that prevented precipitation from entering the tank. The
tank covers helped to reduce the production of sludge 
. The tank did not have any secondary
containment. In the treatment shed, there were one 10,000-gallon and three 20,000-gallon above
ground storage tanks used for storing wood-treating oil. There was also an area where blocks of
solid penta were stored on a concrete pad. Additionally, there were above ground diesel tanks
and a gasoline fuel tank located either within concrete vaults or inside the boiler building. An
east and west running railroad track is located south of the property border. The railroad track is
used for shipping logs to and from the site. The Poles, Inc. property is approximately 15 acres.
Most of the property is not paved.
The pole dipping tank at Poles, Inc. was 95 feet long by 8 feet wide by 12 feet deep with a capacity of approximately 68,000 gallons of penta preservative solution. The wood preservative solution contained approximately 5% penta mixed with Imperial Pole Treating Oil. In a typical treating cycle, 150 pre-processed (peeled and cleaned) raw logs were placed in the tank. Penta oil solution was pumped into the tank at 60 degrees Fahrenheit (ºF). The penta oil solution circulated through a steam heat exchanger that utilized an oil-fired boiler as the heat source. In fall 1999, the current oil-fire boiler replaced an old wood-fired boiler that significantly reduced the heating cycle from approximately 17 hours to 8 hours. Most recently, it took roughly 3.5 hours to heat the oil mixture to 225ºF for the wood treating process. The heated oil was then held in the tank for an additional 3.5 hours before it was drained back into the above ground storage tank. Cool oil was pumped into the tank for another hour to cool the poles. Once the poles were cool, they remained in the tank on steel rails 6 inches above the tank bottom while excess oil dripped off and the poles dried. Once dry, the poles were moved from the dip tank to the storage area until shipment. The whole process including the time for the poles to dry took approximately three days. Poles, Inc. could treat a maximum of 2 - 2.5 batches of poles per week. However, a typical production was one batch of poles per week (IDEQ 2000). Poles were treated in two ways: whole poles were submerged in the penta oil solution, or just one end of the poles were dipped in the penta, called butt dipping. Poles, Inc. modified its wood treatment practices over the years. Poles, Inc. prior to discontinuation installed new tighter sealed covers on the dip tank and the covers were closed when the tank was not in operation and when treating whole poles. During the butt-dipping process, a wrap was placed around the poles to reduce volatilization of the treating oil. In 2001, Poles, Inc. installed an ambient air vapor condensing system that collected and condensed penta vapor emission and recycled it back into the dip tank (EPA 1993, 2002).
The facility operates nine months of the year and is closed during December, January, and February. The nearest residence is approximately 400 feet west of the facility. Idaho Hill Elementary School is located approximately 500 feet south of the facility and situated on a hill approximately 30 feet higher in elevation than the site. A railroad track is situated at the base of the hill running along the southern border of the site. The Oldtown Log Yard, an active log processing business not owned by Poles, Inc. is situated in the narrow strip of property between the railroad tracks and the base of the hill below the school. The log yard does not handle, store, or ship treated poles from the site. The Pend Oreille River, approximately 400 feet north of the facility dip tank, flows in a general north-northwest direction (Appendix A, Figure A-2).
Poles, Inc. has been owned and operated by the Tinling family at its current location since 1945. Prior to 1945, the Great Northern Railroad owned the land. Operations prior to 1945 are unknown. EPA and IDEQ (formally Division of Environment with Idaho Department of Health and Welfare) investigated Poles, Inc. multiple times in the 1980s and early 1990s. The investigations were either routine investigations or a result of odor complaints. No site-specific environmental samples were collected during those investigations. In fall 2000, the Healthy Building Committee, formed by Idaho Hill Elementary School staff members, requested that IDEQ, BEHS and the Cancer Data Registry of Idaho (CDRI) evaluate the site. Concurrently with a citizen's petition, IDEQ requested EPA's involvement for a thorough site investigation. Jointly, EPA and IDEQ conducted a comprehensive site investigation in fall 2001. BEHS is evaluating the potential health risks from the exposures associated with the site activities.
In fall 2000, several teachers and school administrative staff from the nearby Idaho Hill Elementary School raised concerns about a strong chemical smell coming from the facility during pole treatment. Teachers and students experienced eye and throat irritation, headaches, and nausea during the treating process. Additionally, citizens in the border community experienced the same symptoms. School staff members and a concerned citizen contacted the IDEQ, BEHS, and CDRI to investigate the potential exposures and health effects of penta and penta-associated impurities. The community members were also concerned with what was perceived as an elevated cancer rate among current and former schoolteachers at Idaho Hill Elementary.
In response to community requests, IDEQ visited Poles, Inc. on October 19, 2000. During this site visit, IDEQ noted that no objectionable odors were detected and fugitive dust emissions were well controlled. However, the plant was not actively treating poles during the visit (IDEQ 2000). Soon after the visit, to accommodate community concerns, Poles, Inc. changed their pole-dipping schedule so the treatment process occurred when Idaho Hill Elementary was not in session. This schedule continued when the facility restarted operations in the Spring of 2001. In April 2001, IDEQ performed an initial evaluation of potential inhalation exposure to penta utilizing two air dispersion models (IDEQ 2001). BEHS reviewed IDEQ's April 2001 air modeling report and prepared a health consultation to address public health issues (BEHS 2001a, Appendix B). The consultation concluded that there might be a potential inhalation exposure to penta based on the modeling results. BEHS recommended a thorough site exposure investigation for the facility in order to adequately address public health concerns. BEHS convened a conference call to address the community comments and questions regarding the consultation in August 2001. Some of the comments and questions were later summarized in another health consultation to document the issues raised by community members (BEHS 2002, Appendix C).
Besides IDEQ and BEHS activities, CDRI performed a cancer incidence evaluation for the ZIP Code of Oldtown (83822) between 1991 and 1999. For the ZIP Code compared to the reminder of the State of Idaho, the rates of the reported 24 cancer types were all within or lower than their expected ranges (Attachment D, Table D-1). Since Oldtown is a relatively small area, people commute to Oldtown for work or school from different areas or ZIP Codes. CDRI could not rule out the possibility of underestimating the risk (Johnson 2001). Additionally, the initial 24 types of cancer evaluated by CDRI did not include two specific types of cancers for which penta is suspected of being associated.
In May 2001, BEHS and IDEQ convened a public meeting. During this meeting, IDEQ presented the results of the April 2001 air dispersion modeling and proposed the possibility of surface soil sampling at the Poles, Inc. property. At the request of BEHS, the Oldtown Community Advisory Group (CAG) was formed. The CAG is composed of volunteers from Oldtown and nearby communities as well as agency representatives from BEHS, IDEQ, Idaho State Department of Agriculture, EPA, and ATSDR. Members of the CAG suggested that BEHS conduct an epidemiological study and/or biological testing of Oldtown residents and teachers. BEHS and ATSDR stated that the need for additional health studies would be determined after environmental data was available and evaluated. In the mean time, BEHS reviewed the Oldtown situation with the Idaho Cancer Analysis Working Group (CAWG). CAWG members include the Idaho State Epidemiologist and representatives from CDRI, the Bureau of Vital Records and Health Statistics, and BEHS. CAWG requested that CDRI perform another cancer incidence evaluation to better define potentially impacted populations around Poles, Inc. The study included additional target cancer sites that are biologically plausible as a result of the site-specific exposures. The results of this cancer incidence evaluation are discussed in section 5.2.3 of this public health assessment.
In June 2001, IDEQ sampled surface soil between the Poles, Inc. treatment dip tank and the school fence line (Appendix E). Penta concentrations in the samples decreased as distance to the dip tank increased. Penta was not detected in soil taken from outside the pole yard border. However, high levels of penta were detected in the soil near the dip tank (IDEQ 2001). These results further supported the need for EPA's involvement.
EPA convened a meeting with the CAG in June 2001 to discuss the multiple, ongoing activities that were proposed by EPA and IDEQ. Given the community interests in petitioning EPA's action, BEHS'S recommendation, and IDEQ's requests, the EPA's Superfund Technical Assessment and Response Team (START) contractor, Ecology and Environment, Inc. (E&E) performed an Integrated Assessment (IA) at the Poles, Inc. Oldtown site. At this meeting, EPA discussed the IA and the public health goals for the IA. Those goals were: (1) to identify and conduct a removal assessment of potentially contaminated environmental media at the site; (2) to characterize the potential sources of contamination; (3) to acquire adequate information to determine whether the site is eligible for placement on the National Priorities List; (4) to document threats or potential threats to public health posed by the site; and (5) to determine whether removal actions are warranted. BEHS reviewed the START IA sampling plan and commented on it in the form of a health consultation (BEHS 2001b, Appendix F). EPA incorporated BEHS and IDEQ's comments before finalizing the IA plan and conducting environmental sampling.
START collected samples for air, surface soil, subsurface soil, sediments of the Pend Oreille River, groundwater, and indoor dust samples. Samples particularly focusing on Idaho Hill Elementary included indoor air samples, wipe samples in Classroom 1, which is the closest to the facility, and surface soil samples from the school playground. Dip tank products including sludge and oil were tested. Because the penta treatment oil is a complex mixture of many chemicals, START analyzed the collected samples for heavy metals, semivolatile organic compounds (SVOCs) which included penta, and volatile organic compounds (VOCs). START completed the final Poles, Inc. IA Report in January 2002 (EPA 2002a).
After EPA's investigation, EPA requested Poles, Inc. hire a contractor to perform a dip tank integrity study. Poles, Inc. hired Mountain Construction Services in September 2001. Cracks were found in the floor's center, the southwest corner welds, and on the west wall of the tank. The cracks ranged from 0.06 to 1.5 inches. All cracks were repaired by the contractor after the inspection (EPA 2002a).
On June, 18, 2002, EPA START conducted limited dioxin and furan sampling at the Poles, Inc. facility. They collected one groundwater, one product, and five surface soil samples to test for polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF). The sampling was to complete data gaps from the 2001 IA (EPA 2002b). Surface soil samples were collected at the top of a trail along the north bluff of Idaho Hill Elementary school, from the playground at the school, from a residence on the edge of the site, from the treated butt-dip pole storage area and a background surface soil was collected near the intersection of East 7th South and Meadowdale Streets (the same background location was used during the IA). A groundwater sample was collected from the monitoring well east of the dip tank and a product sample was collected from the dip tank itself. START completed their report in August 2002 (EPA 2002b).
BEHS is preparing this public health assessment relying on the data and information provided from the START IA (EPA 2002a), the START dioxin/furan sampling (EPA 2002b), and the IDEQ soil sampling report (IDEQ 2001b). Data demonstrated to have Quality Assurance/Quality Control (QA/QC) problems were not used in this public health assessment. IDEQ's April 2001 air modeling results were not used due to high uncertainties of the modeling outcome.
According to the 2000 US Census, the population of Oldtown is approximately 190. Since Oldtown is a relatively small town and it immediately borders Newport, Washington, the estimated population that may potentially be impacted by the facility needs to include residents of Newport. E&E estimated the population within a 1-mile radius of the site to be 2586 and 3722 within a 4-mile radius of the site. Those estimates are based on the sum of (1) census data for Newport and Oldtown; and (2) multiplying the house count for people outside city limits by the average number of persons per household (2.5) for Bonner and Pend Oreille Counties (EPA 2002a). Citizens in Priest River, a town six miles west of Oldtown, have expressed concerns about the site because many people in Priest River drive to the Oldtown/Newport area for work or school. The population of Priest River in 2000 was 1754 (Census 2000). Approximately 10 people work at the Poles, Inc. facility. It is currently not known from where those employees commute to work.
3. ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS
An essential part of every public health assessment is to review environmental contaminants on the site. In this section, BEHS has listed the contaminants of concern. BEHS evaluates these contaminants in the subsequent sections of the public health assessment to determine whether exposure to them has any public health significance. The results from environmental testing at the Oldtown site are summarized for each different environmental media (e.g., air, groundwater, surface soil, subsurface soil, etc.).
Concentrations of chemicals in each of the media have been compared to media-specific health-based comparison values developed by ATSDR to decide whether any of the chemicals need further evaluation. Health-based comparison values are derived using chemical toxicity information and assuming frequent human exposure to contaminants (e.g., a residential setting rather than industrial setting). For non-cancer toxicity, BEHS typically uses Environmental Media Evaluation Guides (EMEGs) derived from ATSDR's Minimal Risk Levels (MRLs) or the Reference Dose Media Evaluation Guides (RMEG) derived from EPA's References Doses (RfDs). MRLs and RfDs are estimates of daily human exposure to a contaminant that is unlikely to cause adverse non-cancer health effects over a lifetime. Cancer Risk Evaluation Guides (CREGs) are risk comparison values based on EPA's chemical-specific cancer slope factors and an estimated excess lifetime cancer risk of one in one million. Therefore, if the concentration of a chemical is less than its comparison value, it is unlikely that exposure would result in adverse health effects. Further evaluation of exposures to that chemical is not warranted. If the concentration of a chemical exceeds a comparison value, adverse health effects from exposure are not necessarily expected, but potential exposures to that chemical at the site should be evaluated.
In addition to the health-based comparison values, BEHS also references other standards and regulations when health-based comparison values are not available or when other standards are lower than the health-based comparison values. EPA's Maximum Contaminant Level (MCL) is the highest level of a contaminant that is allowed in drinking water. MCLs are enforceable standards and they are set as close to Maximum Contaminant Level Goal (MCLG) as feasible. MCLG is the level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs are non-enforceable public health goals. The Lifetime Health Advisories for Drinking Water (LTHAs) are lifetime exposure levels for drinking water at which adverse, noncarcinogenic health effects would not be expected to occur. EPA also recommends secondary standards that are non-enforceable guidelines regulating contaminants that may cause cosmetic or aesthetic effects (e.g., smell, taste, and color) in drinking water. The secondary standards are not health-based. Sometimes secondary standards are 10 to 100 times lower than levels that would induce health effects. Ambient and indoor air measurements have been compared to Idaho Ambient Air Criteria (IAAC) and EPA Region IX's Preliminary Remediation Goals (PRGs) for air. Surface soil and sediment concentration have been compared to EPA Region IX's PRG for residential soil. The lowest of all comparison values was used to identify compounds for further evaluation. The abbreviation of above described guidelines, standards, and criteria are summarized in the following Table.
Table 1. Summary of Comparison Values and other Environmental Standards
|
Guides, Regulations, Standards |
Unit | Unit Example | Target Media | Regulatory (Y/N) | Health Based (Y/N) |
|
CREG |
concentration | µg/M3, µg/kg, µg/L | air, soil, water | N | Y |
|
EMEG |
concentration | µg/M3, µg/kg, µg/L | air, soil, water | N | Y |
|
IAACa |
concentration | µg/M3 | air | Y | Y |
|
LTHA |
concentration | µg/L | water | N | Y |
|
MCL |
concentration | µg/L | water | Y | Nb |
|
MCLG |
concentration | µg/L | water | N | Y |
|
MRL |
dose | mg/kg/day | -- | N | Y |
|
PRG |
concentration | µg/M3, µg/kg, µg/L | air, soil, water | N | Y |
|
RfD |
dose | mg/kg/day | -- | N | Y |
|
RMEG |
concentration | µg/M3, µg/kg, µg/L | air, soil, water | N | Y |
|
Secondary |
concentration | µg/L | water | N | N |
a: an criterion for incremental air release; applicable to
new facility or change of operation for existing facility
b: MCL was set as close to the health based MCLG as feasible using the best
available treatment technology and taking cost into consideration.
The public health implications of exposures to selected contaminants are evaluated in detail in the discussion section of this document. With this in mind, the following summary of environmental data highlights the target chemicals that have been found on the site at levels above the comparison values. The sampling location identification numbers referenced in this public health assessment are the same as the START IA report (EPA 2002a) and the START dioxin/furan sampling (EPA 2002b). The details about the selection of contaminants of concerns are summarized in Appendix G.
The following sections present air sampling results from the START IA report. Air samples were taken while Poles, Inc. was butt-dipping the poles. It is generally believed that the butt-dipping process generates the worst case air emission scenario. Air samples represent the air concentrations at that particular sampling time period. The results do not represent the past exposures before the change of operation.
Twenty-one outdoor air samples (including background) were collected from August 23rd through 25th, 2001. Samples were collected from seven locations over three consecutive 24-hour sampling periods and were analyzed for SVOCs. The temperatures during the sampling period ranged from 40 to 90 ºF. The most common wind direction was west southwesterly following the Pend Oreille River Valley. A meteorological station 1000 feet east of the treatment shed recorded the weather information. The downtown/residential areas of Oldtown/Newport are located within half a mile west-northwest of the site. Penta is the only compound that was detected in the outdoor air at concentrations above the comparison value. In general, the highest penta concentrations were found next to the wood treatment area (0.01 to 0.63 microgram penta per cubic meter air, µg/M3) with an exception of the first day where the highest concentration was detected at a nearby residence (1.48 µg/M3) downwind from the facility at the time of sampling. The penta air sampling analytical data are summarized in Table 2. As a reminder, comparison values for air are theoretical calculations assuming daily exposure over 30 years. Since the exposure to this level of contamination would only occur during the pole treatment process (once a week), the use of these comparison values is a conservative (protective) tool for screening purposes.
Table 2. Pentachlorophenol August 2001 Air Sample Analytical Results, Poles, Inc.
|
Location ID |
Location Description | Aug. 22-23 | Aug. 23-24 | Aug. 24-25 |
| PY04AM | 400 feet south of the site at the school |
BDL |
BDL | BDL |
| PY01AM | 1000 feet east of the site |
BDL |
BDL | BDL |
| PY02AM | 120 feet north of the site near Pend Oreille River bluff |
0.1a |
0.03a | 0.06a |
| PY03AM | 800 feet west of the site at adjacent residence |
1.48a |
BDL | BDL |
| PY05AM | 50 feet east of the dip tank |
0.01a |
0.63b | 0.49b |
| PY07AM | 2000 feet northeast of the site at the north side of the river |
0.05a |
BDL | BDL |
| PY08AM | 2520 feet east of the site |
R |
BDL | BDL |
| PY06AM | Indoor air samples (school hallway) |
BDL |
BDL | BDL |
a: Penta was positively identified. The number is an unknown
bias estimate.
b: Penta was positively identified. The number is a low
bias estimate.
BDL: Below detection limit. The detection limit is between
0.16 - 0.18 µg/M3.
R: Rejected.
Three indoor air samples were collected from August 23rd through 25th, 2001. The samples were collected from inside of the School over three consecutive 24-hour sampling periods and were analyzed for SVOCs. The sampling station was near Classroom 1 in the school hallway directly beneath the air vent. The outdoor air intake for this air vent is the closest to the facility. All the detected indoor air contaminants were at concentrations below their comparison values. Penta was not found in indoor air. The most prevalent wind direction during the sampling period was west-southwest direction following the Pend Oreille River Valley. The school was not downwind during the sampling period.
During the air sampling event, light to moderate odor was noted by the START investigators while in the school. According to school staff, the odor issue for the school improved once Poles, Inc. began treating poles at night. In addition, the odor has been less noticeable since Poles, Inc. installed a vapor condensing system, according to respondents of the Oldtown Community Health Concerns Survey (Appendix M). The facility is no longer treating poles, therefore eliminating the odor issue.
The following sections present soil sampling results from the IDEQ soil sampling study and the START IA and START dioxin/furan sampling. In this public health assessment, BEHS identified samples within Poles, Inc. property as "onsite" and included the log-storage area, penta sack disposal area, wood waste disposal area and part of the Pend Oreille river bank.
3.2.1 Onsite Surface and Subsurface Soil
In June 2001, IDEQ collected 10 surface soil samples (including background) between Poles, Inc. dip tank and the school fence line. Surface soil grab or composite samples were taken from 120, 170, 220, 270, 320, and 370 feet away from the dip tank toward the school (Appendix E, Figure E-1). A composite sample is a combination of five grab samples representing the same distances away from the dip tank. Soils were analyzed for SVOCs. In the onsite surface soil, the maximum concentration of six contaminants were higher than the health-based comparison values (benzo(a)anthrancene, benzo(b)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, Ideno(1,2,3-cd)pyrene, and penta) (Appendix G, Table G-1). Except for penta, the composite sample collected around the railroad track (270 feet) and the haul road (320 feet) generally had the highest concentrations for all other detected contaminants. The highest concentrations were 0.77 milligram per kilogram (mg/kg) for benzo(a)anthrancene, 1.64 mg/kg for benzo(b)fluoranthene, 0.615 mg/kg for benzo(a)pyrene, 0.125 mg/kg for dibenzo(a,h)anthrancene, and 1.28 mg/kg for ideno(1,2,3-cd)pyrene. The highest concentration for penta was 234 mg/kg in soil collected 170 feet away from the dip tank. Generally, the further away from the dip tank, the lower the penta soil concentrations. Penta was not detected in any sample locations beyond the railroad track toward the school.
In August 2001, START took onsite soil samples from the ground surface to about 80 feet below ground (above groundwater level). Subsurface soil was collected in order to characterize the potential impact to groundwater. The surface soil sampling locations included four samples around the treatment shed, six samples around the log storage area, and one sample at the penta storage sack area. Fourteen subsurface soil samples were collected from seven locations around the treatment shed (Appendix A, Figure A-2). The top 6 inches of soil was defined as surface soil. The upper part of subsurface soil ranged from 10 to 40 feet below ground surface (bgs) and the lower part of subsurface soil ranged from 75-80 feet bgs. Wood-treating oil stains and/or petroleum odors were observed in one surface soil sample and five subsurface soil samples collected from three locations around the treatment shed. According to E&E's estimation, the total volume of penta and oil impacted subsurface soil is approximately 3700 cubic meters (4978 cubic yards) (EPA 2002a).
START soil samples were analyzed for metals, chlorinated pesticides, SVOCs, and VOCs. The amount of contamination was generally greater in the lower portions of the subsurface soil. The maximum concentrations of five contaminants in subsurface soil were higher than the health-based comparison values (arsenic, benzo(a)anthrancene , benzo(b)fluoranthene, dibenzo(a,h)anthracene, and penta). Arsenic levels ranged from 6.9 to 16.9 mg/kg. Subsurface soil background arsenic concentrations ranged from 7.8 - 9.1 mg/kg. The maximum concentrations for benzo(a)anthrancene, benzo(b)fluoranthene, dibenzo(a,h)anthracene, and penta were 3, 2.6, 0.07, 0.14, and 1700 mg/kg, respectively (EPA 2002a). However, exposures to onsite subsurface soil 10-80 feet bgs is highly unlikely for the public.
BEHS identified two contaminants, arsenic and penta, in the onsite surface soil that have higher concentrations than the health-based comparison value. Arsenic in surface soil ranged from 6.2 to 15 mg/kg, higher than the CREG of 0.5 mg/kg, but similar to site and regional background levels. Arsenic concentrations are not a site-related issue since Poles, Inc. has never used arsenic in its wood-treating process. From a public health perspective, BEHS evaluates the results of arsenic in each environmental media separately from the site-related issue. Details can be found in Section 3.7.2.
Penta was detected in eight out of 10 onsite surface soil samples. The highest penta concentration, 600 mg/kg, was found at the east log-storage area (PY03SS). The west side of this log-storage area is regularly used by locals as a shortcut between the school/residential area and downtown Oldtown/Newport. Other SVOCs detected by START were below comparison values.
Wood-treating compounds have migrated to surface and subsurface soils from past and recent site activities. Contaminated surface soil around the log storage area may be due to air deposition or from treated poles dripping onto the ground. Contaminated subsurface soil around the treatment shed may be due to accidental spills and the cracks found at the bottom of the dip tank.
In June 2002, START collected one surface soil sample (PY03SS02) on site from the butt-dip pole storage area. While PCDDs and PCDFs were detected, the Toxicity Equivalent Quotient (TEQ) was below ATSDR's health-based comparison value. The TEQ represents the toxicity-related value that combines the toxicities for all dioxin-like PCDDs/PCDFs and expresses them as a sample concentration term for only one congener, 2,3,7,8-tetrachlorodibenzo-p-dioxin. The concentration of all of the congeners is expressed as a single value (EPA 2002b).
The surface soil sampling study conducted by IDEQ in June 2001 included one grab and one composite sample at the Idaho Hill Elementary school fence line. The composite sample is a combination of five grab samples representing the school fence line. Samples were analyzed for SVOCs. SVOCs were not detected in the IDEQ offsite surface soil samples (Appendix G, Table G-1).
Seven offsite surface soil samples were collected by START in August 2001. The offsite samples included a background sample, a sample taken from the closest residence (right by the wood waste disposal area), three samples around the school, and two samples from the school playground. Samples were analyzed for metals, chlorinated pesticides, SVOCs, and VOCs. Arsenic concentrations ranged from 5.8 to 8.8 mg/kg similar to the background ranges. It is important to reiterate, arsenic is not known to be associated with the site activities (EPA 2002a). None of the detected pesticides, SVOCs, and VOCs had concentrations higher than the comparison values. Penta was detected east of the school playground area near trees (SC05SS) and a nearby residence at levels 0.096 and 0.059 mg/kg, respectively, far below the soil CREG for penta (4 mg/kg).
Wood-treating compounds from past and recent site activities were not found at levels above comparison values in the offsite surface soil. Contaminated surface soil onsite and future air emissions, erosion, and deposition may result in future off-site surface soil contamination. However, it is not possible to determine the probability or the levels of future contamination based on the available information.
Four offsite surface soil samples were collected by START in June 2002. The offsite samples included a background sample, a sample taken from the closest residence (right by the wood waste disposal area), one sample on the bluff near the school, and one sample from the school playground. Samples were analyzed for PCDDs and PCDFs. The calculated TEQ was below ATSDR's health-based comparison values.
Three sediment samples were collected by START from the Pend Oreille River to determine whether contaminants are migrating from potential sources at the site toward the river. A background sample was collected from the northeast of the site, approximately 350 feet upstream from the probable point of entry (PPE). One sample was collected at the PPE and the other was collected downstream from the PPE. PPE is the most direct route of surface water drainage from the site into the river. Poles, Inc. does not have a surface water collection system and the site is relatively flat. Water at the site would either drain into the soil or follow the path of a little used dirt road, determined by EPA to be the PPE (Appendix A, Figure A-2) (EPA 2002a). None of the detected pesticides, SVOCs, or VOCs were at levels of health concern. Arsenic sediment background was 5.3 mg/kg. Arsenic levels at the PPE and downstream of the site were 5.2 and 5.7 mg/kg, respectively. The onsite surface soil contamination currently does not appear to reach the river.
During the IA, START collected eight groundwater samples from five monitoring wells around the treatment shed during two sampling events. The monitoring wells were installed in August 2001. Five samples were taken at the time prior to well development. Those samples are not used in this public health assessment because they may be biased due to possibly high dissolved solids from unsettled, disturbed well water. START re-sampled three wells (TP04, TP06, and TP05) after well development in January 2002. These wells were 88.5 feet bgs and the groundwater samples were taken at approximately 77.5 feet bgs. The groundwater samples were analyzed for metals, chlorinated pesticides, SVOCs and VOCs. Penta along with 12 metals showed elevated concentrations compared to health comparison values. Penta was detected in one of the wells at 46 micrograms per liter (µg/L). The maximum concentrations for metals were 115000 µg/L for aluminum, 14 µg/L for antimony, 344 µg/L for arsenic, 1970 µg/L for barium, 9 µg/L for beryllium, 214 µg/L for chromium, 199 µg/L for cobalt, 298000 µg/L for iron, 327 µg/L for lead, 174 µg/L for nickel, 17 µg/L for thallium, and 297 µg/L for vanadium. Most reported metal concentrations were similar among three monitoring wells. Metals were not known to be used in Poles, Inc. wood-treating process (EPA 2002a).
START collected one groundwater sample from existing monitoring well #3 in June 2002 to test for PCDDs and PCDFs. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and 2,3,7,8-tetrachlorodibenzofuran (TCDF) were not detected in the groundwater sample, but other congeners of the contaminants were detected at a combined TEQ level above the ATSDR health-based comparison value. However, the groundwater pathway is not a completed exposure pathway (for more information on the groundwater pathway see Section 4.2.1). BEHS did not evaluate PCDD and PCDF concentrations further. It is not expected that private wells are located down gradient of the Oldtown site (EPA 2002a); therefore, the wells are not likely to be impacted by contamination. However, domestic wells were not sampled during the START IA and the exposures cannot be determined until further monitoring is completed and a beneficial well use survey is completed.
There are 46 domestic wells and 13 public wells located within a 1-mile radius of the site according to the well logs maintained by Idaho and Washington. The nearest well is located approximately 2500 feet southeast (up gradient) of the site. The Oldtown/Newport public water supply system primarily uses surface water taken upstream of the facility. Eight public wells are occasionally used for the Oldtown/Newport public water supply system when water demands are high. Those wells are up gradient of the site and SVOCs were routinely tested for in the wells. SVOCs were not detected in 1993, 1994, 1996, and 1998 sampling (Taylor 2002). In August 2001, IDEQ sampled the West Bonner Well (one of the public wells) and analyzed water for polynuclear aromatic hydrocarbons (PAHs), penta, and VOCs. The only detected chemical was trichloroethylene at 2.7 µg/L, which was higher than the EPA Region IX tap water PRG (1.6 µg/L) but lower than the MCL (5 µg/L). This contamination may be attributable to a nearby former dry cleaner but does not appear to relate to Poles, Inc. The Oldtown/Newport public water system stopped using this well after IDEQ's finding (EPA 2002a).
It is not known whether the monitoring wells are in the same aquifer as any of the nearby drinking water (private or public) wells. Groundwater in the vicinity of the site flows to the east to northeast towards the Pend Oreille River and may ultimately enter the River. Surface water was not sampled in the START IA (EPA 2002a) or in the START dioxin/furan sampling (EPA 2002b).
Wipe samples were taken by START during the IA to determine whether contaminants have migrated from the potential sources at the site and deposited onto the school property. Three SVOC wipe samples were collected from Classroom 1 at the school. Two samples were collected from potentially high-contact areas in each of the classroom walls (composite of four wipes). The third sample was collected from the top of each fluorescent light fixture in an area not regularly cleaned (composite of six wipes). This classroom was intentionally not painted or cleaned after the end of the last school year to ensure that wipe samples represented the conditions during the year. The dust sample on top of the fluorescent light fixtures accumulated over the year. SVOCs were not detected in any of the wipe samples. The low levels of the wood treating contaminants do not appear to have deposited and accumulated in Classroom 1 through the air migration pathway (EPA 2002a).
The treatment shed area of Poles, Inc. has a locked gate but the remainder of the property is not fenced. The public regularly access through the pole yard and the log processing yard as a shortcut between the school/residences and the downtown area of Oldtown/Newport. During the multiple site visits conducted by BEHS, IDEQ and EPA, the investigators observed frequent trespassers including children disregarding multiple "no trespassing" signs (Appendix H). According to the Idaho Hill Elementary school staff; however, the signs were relatively new additions to the site (installed prior to EPA sampling event in August 2001). The frequently trespassed area is full of piled logs, debris, and heavy equipment. A nearby resident told the BEHS investigator that it is common to see elementary school children playing at the area after school. BEHS could not exclude the possibility of physical hazards.
Poles, Inc. is located adjacent to the Pend Oreille River which is used for recreational boating and fishing. START did not find wood-treatment chemicals in sediments collected from the river. However, the contaminated groundwater from the site is expected to flow toward and to ultimately enter the Pend Oreille River. During the IA, START personnel did not observe fishing activities near the site, but did observe boats with fishing gear both upstream and downstream of the facility. The amount of fish caught from the river that were consumed by anglers is unknown (EPA 2002a). Recreational sportsmen and children may come in contact with surface water. Surface water, fish, or other biota was not sampled in the IA.
As described throughout sections 3.2 to 3.5, the elevated arsenic levels were found in surface soil (5.7 - 15 mg/kg), subsurface soil (6.9 - 16.9 mg/kg), and sediments (5.2 - 5.7 mg/kg). The soil arsenic results are similar to the area background level. The site-specific background arsenic levels were 9.7 mg/kg in surface soil and 9.1 mg/kg in the upper and 7.8 mg/kg in the lower portions of the subsurface soil, and 5.3 mg/kg in the river sediment. These background levels are similar to the Spokane Basin area average (9 mg/kg). The Spokane Basin, 40 miles south of Oldtown is the nearest geographic region for which natural arsenic soil background concentrations were reported. Elevated heavy metals including arsenic (0.15 - 0.34 mg/L) were found in groundwater samples (EPA 2002a). However, arsenic does not appear to be a concern for the public drinking water system. Prior to the chlorination process, arsenic detected in the Newport public water system was 0.01 mg/L (Woodke 2002). The health implications of being exposed to arsenic are part of the discussion in this public health assessment. Arsenic is not related to the site activities.
BEHS evaluates the environmental and human components that lead to exposure. Human contact with environmental contamination is only possible when a completed exposure pathway exists. A completed exposure pathway exists when all of the following five elements are present: (1) a source of contamination; (2) transport through an environmental medium; (3) a point of exposure; (4) a route of human exposure; and (5) an exposed population.
ATSDR categorizes an exposure pathway as a completed or potential exposure pathway if the exposure pathway cannot be eliminated. Completed pathways require that all five elements exist and indicate that exposure to a contaminant has occurred in the past, is currently occurring, or will occur in the future. Potential pathways, however, require that at least one of the five elements is missing, but could exist. Potential pathways indicate that exposure to a contaminant could have occurred in the past, could be occurring now, or could occur in the future. An exposure pathway can be eliminated if at least one of the five elements is missing and will never be present. Table 3, Table 4, and Table 5 summarize the pathways for the Oldtown site. The discussion following these three tables concentrates on the pathways that are of public health significance and relevant to the site. Eliminated pathways are briefly described. As an additional note, even though an exposure pathway might be complete or potential, it does not necessarily mean there is a public health risk from the exposure pathway contamination. For a public health risk to occur, contamination in a completed or potential exposure pathway must be present in a substantial enough dose. Further explanation of this can be found in Section 5.1.
4.1 Completed Exposure Pathways
A completed exposure pathway requires all of the five elements to be present: (1) a source of contamination; (2) transport through an environmental medium; (3) a point of exposure; (4) a route of human exposure; and (5) an exposed population. Table 3 lists the completed exposure pathways for the Oldtown site.
Table 3. Completed Exposure Pathways
|
Source |
Media | Point of Exposure | Route of Exposure | Exposed Population | Time | Status |
| Poles, Inc. | onsite surface soil | Poles property | eating skin contact |
workers, trespassers, children playing in log storage area | Past | completed |
| Present | completed | |||||
| Future | potential | |||||
| Poles, Inc. | offsite surface soil | Nearby homes and school | eating skin contact |
nearby residents, gardeners, children playing in school playground, school teachers and staff | Past | potential |
| Present | completed | |||||
| Future | potential | |||||
| Poles, Inc. | sediment | Pend Oreille River bank | eating skin contact |
sport fishermen, children playing along the river | Past | potential |
| Present | completed | |||||
| Future | potential | |||||
| Poles, Inc. | air, fumes and dust | Poles, Inc. property, nearby area | breathing | workers, residents nearby, school children, teachers and staff | Past | completed |
| Present | completed | |||||
| Future | potential |
A completed air exposure pathway exists for past exposures. Higher contaminant concentrations in the past versus the most recent past could have been possible because Poles, Inc. recently installed, prior to their removal, new covers on the dip tank that had a tighter seal and a vapor condensing system. Poles, Inc. also shortened the wood treatment process with a more efficient boiler. The new covers and the vapor condensing system minimized and controlled part of the air emissions. A shorter heating process reduced the time for air emissions to occur. The odor was better controlled and the air emissions improved over time. However, it is not possible to estimate air quality for both indoor and outdoor air prior to the recent air sampling during the IA. Presently, the facility is no longer treating poles and had decommissioned and dismantled the treatment tank at the site. Future exposures to site-related contaminants through the air pathway are possible.
Nearby residents, workers, and trespassers could be have been exposed to certain SVOCs during the wood treatment process. Higher SVOC concentrations were detected outdoors close to the treatment area. Penta was detected in nine out of 24 air samples taken between August 23rd and 25th, 2001.
A completed onsite soil exposure pathway exists currently, as well as in the past. Residents, including children, trespass on the site. Contaminants have migrated from the surface soil into the subsurface soil to 80 feet bgs. Contaminants found in the onsite surface soil include multiple metals, SVOCs, and VOCs. Residents, children, school staff, and site workers are currently being exposed and could have been exposed in the past. Penta and arsenic were found at levels higher than the health-based comparison values; therefore, the public health implications of these exposures will be further evaluated.
Trespassers on the site could come in contact with contaminated soils and be exposed to chemicals. Since children have been reported to play around the log storage area, it is likely that they are exposed to contaminants by accidentally eating contaminated soils or touching the treated logs, if any continue to remain on site. Young children and infants could be exposed to dirt that was carried home with workers and trespassers. Exposure can occur through ingestion, skin contact, or both.
A completed exposure pathway currently exists. Nearby residents, particularly gardeners, children playing in school playground, school teachers and staff could be exposed to soils that contain metals, chlorinated pesticides, SVOCs, and VOCs. Young children frequently put foreign objects in their mouth and some children may eat dirt. These children may be exposed to more contamination due to increased ingestion of soil. However, detected contaminants related to the wood treatment process were all lower than health-based comparison values. Future exposure to site related chemicals through offsite soil is possible but unlikely, especially considering that the facility is no longer treating poles. Without major changes in operation, such as beginning the treatment of poles again using penta, elevated future exposure to offsite surface soil is unlikely because the contaminants did not transfer offsite significantly during the past decades. Arsenic levels in nearby household and the school play area ranged from 5.7 to 8.8 mg/kg, lower than the reported background level of 9.7 mg/kg.
A completed sediment exposure pathway currently exists. Sport anglers, nearby residents, and children playing along the river could be exposed to sediment containing metals, SVOCs, and VOCs. Contaminants related to site activities include two SVOCs and one VOC. The levels were a thousand to a hundred thousand times lower than the comparison values. Arsenic in sediment ranged from 5.2 to 5.7 mg/kg, similar to the sediment background of 5.3 mg/kg. Contaminated groundwater onsite in general flows towards and eventually enters the Pend Oreille River. This may influence future sediment contamination. Future exposure to contaminated sediment is possible but unlikely because the site contaminants did not migrate significantly over the years.
4.2 Potential Exposure Pathways
A potential exposure pathway is defined as one where exposure could be possible except that one or more of the five elements is missing. In some cases, this means that the exposure is not possible now but may be possible in the future. In other cases, an exposure may be possible but cannot be confirmed because data are not available. The potential pathways for the Oldtown site are summarized in Table 4.
Table 4. Potential Exposure Pathways
|
Source |
Media | Point of Exposure | Route of Exposure | Exposed Population | Time | Status |
| Poles, Inc. | groundwater | residential wells | eating skin contact breathing |
people who use wells as drinking water | Past | potential |
| Present | potential | |||||
| Future | potential | |||||
| Poles, Inc. | surface water | Pend Oreille River | skin contact | recreational sportsmen, children playing along the river | Past | potential |
| Present | potential | |||||
| Future | potential | |||||
| Poles, Inc. | biota | fish | eating | consumers of fish or other water biota | Past | potential |
| Present | potential | |||||
| Future | potential |
A potential groundwater exposure pathway exists for individuals who use private wells as their drinking water source. However, most people obtain drinking water from the Oldtown/Newport combined public water supply system. The municipal water supply system serves about 2250 people in the Oldtown and Newport area. It uses surface water from a spring approximately 1.5 miles south (up stream) of the site as the primary water source. When additional capacity is required, eight municipal wells located approximately 0.75 miles southwest (up gradient) of the site may be blended with the surface water. EPA estimated about 30% of the public drinking water is coming from groundwater (EPA 2002a). The public water system discontinued using water from the West Bonner Public Well after IDEQ's July and September 1994 sampling results indicated the presence of trichloroethylene in well water (Lyon 2002). However, trichloroethylene is not likely to be an Oldtown site-related contaminant.
Well logs maintained by Idaho and Washington indicate that there are 46 domestic wells within a 1-mile radius and 530 domestic wells within a 4-mile radius of the site. It is not known if those domestic wells are drawing groundwater from the same aquifer as EPA's monitoring wells or if those private wells are impacted by the groundwater contamination onsite. Since none of the private wells are located down gradient of the Oldtown site (EPA 2002a), the wells are not likely to be impacted. However, domestic wells were not sampled during the START IA and the exposures cannot be determined. BEHS recommends that further groundwater monitoring be conducted at the site and that a beneficial well use survey be conducted to determine if site contamination is migrating off site and if there are any private drinking water wells located down gradient of the site.
A potential surface water exposure pathway exists for individuals who come in contact with the river. Those individuals include recreational sportsmen and children playing in the Pend Oreille river. The River is used as a source of drinking water and recreational boating and fishing. There are three water intakes within 15 miles upstream of the facility. No surface water is taken as a drinking water source within 15 miles downstream of the site. Site-related contaminants were found in groundwater that flows toward and may be entering the river. If penta migrates into surface water, it will undergo biotransformation and photolysis (breaking down by sunlight). Penta is more likely to be absorbed into the sediment than to stay in water or volatilize into air. The river sediment showed low levels of site-related contaminants. Exposure to penta through contacting surface water is unlikely.
4.2.3 Biota - fish and other water organisms
A potential exposure pathway exists for individuals who consume biota such as fish and other water organisms from the Pend Oreille River. Those individuals could include sports fishermen and their families and friends who share the catch. EPA does not know how much fish is caught near the site for human consumption from the river. In this case, it is unlikely that significant amount of penta would accumulate in fish caught from the Pend Oreille River. Penta is less likely to stay in river water than in sediment, and the river sediment showed low levels of site-related contaminants.
Eliminated exposure pathways are defined when exposure is unlikely and that one or more of the five elements ((1) a source of contamination; (2) transport through an environmental medium; (3) a point of exposure; (4) a route of human exposure; and (5) an exposed population.) is missing. This means that the exposure is not possible now and it is not likely to be possible in the future. The eliminated pathways for the Oldtown site are summarized in Table 5.
Table 5. Eliminated Exposure Pathways
|
Source |
Media | Point of Exposure | Route of Exposure | Exposed Population | Time | Status |
| Poles, Inc. | onsite subsurface soil | Poles property | skin contact eating |
workers during site construction (if any) | Past | potential |
| Present | eliminated | |||||
| Future | eliminated | |||||
| Poles, Inc. | dust wipe samples | school; possibly nearby residence | eating skin contact |
residents, school children, teachers and staff | Past | eliminated |
| Present | eliminated | |||||
| Future | eliminated |
Exposure to onsite subsurface soil is highly unlikely for the general population. It was only possible for workers during past construction activities. It is not know if this activity existed. The current and future exposure pathways to subsurface soil for the public are eliminated.
Three wipe samples were collected in Classroom 1 of Idaho Hill Elementary by START during the IA. START did not find any detectable contaminants in the dust wipe samples. The exposure pathways through indoor dust are eliminated.
Next Section Table
of Contents
