PUBLIC HEALTH ASSESSMENT
POWELL ROAD LANDFILL
DAYTON, MONTGOMERY COUNTY, OHIO
On site refers to the location of the landfill (within the fenced area) and also along the fenced edge of the landfill. Off site refers to the remainder of the Remedial Investigation area (Figure 1, Appendix A).
Chemicals presented in this section will be discussed in further detail in other sections of this document. Chemicals listed in these data tables are not necessarily a threat to human health and may be eliminated in other sections of the public health assessment.
Comparison values are numbers used as guides to aid in the determination of the chemicals of concern at a site. If a chemical concentration exceeds the comparison value and is in a human exposure pathway (i.e. drinking water), it may be retained as a chemical of concern. Comparison values have been developed specifically for drinking water, soil, and air. Comparison values have not been developed for other media.
Comparison values for chemicals that do not cause cancer are either the ATSDR Environmental Media Evaluation Guides (EMEGs) or are calculated by ODH. Calculated comparison values used the U.S.EPA standard Reference Dose (RfD), body weights, and ingestion rates for adults. The comparison values for drinking water are either the U.S.EPA Maximum Contaminant Level (MCL), EMEGs, or the calculated value, whichever is the lowest number. Cancer Risk Evaluation Guides are estimated contaminant concentrations based upon the probability that 1 additional cancer case may occur in excess of the number that will be expected to occur among 1 million people (assuming they have been exposed to the contaminant for a lifetime). Cancer Risk Evaluation Guides are calculated from U.S. EPA's cancer slope factors. The formulas used for calculating comparison values are located in Appendix C.
On-site environmental monitoring data included gas vent vapor and liquid, surface leachate, ambient air, surface and subsurface soil, soil gases, and groundwater (along the fenced edge of the land-fill). Vent vapor was a sample of material from the gas vents present in a gaseous form. Vent liquids were samples of liquid taken from gas vents on the landfill.
Gas Vent Vapor and Liquid
Samples of the vent vapor and vent liquids discovered a number of volatile organic compounds (VOCs), semivolatile organic compounds and metals (Table 1).
On-Site Gas Vent Vapor and Vent Liquid Analysis
for Volatile Organic Compounds
at Powell Road Landfill
|NR = Not Reported|
|Dames and Moore, 1990|
Eleven VOCs were detected in both vent vapors and liquids (Table 1). The distribution of VOCs in vent liquids was different from that of vent vapors (Figures 2 and 3, Appendix A). There were pockets of high VOC concentrations in the liquid samples in the central and northeastern portions of PRL (Figure 3). There is also a pocket of VOCs in the south eastern section of the landfill. Volatile organic compounds in vent vapor increase from east to west across the landfill (Figure 2).
Semivolatile concentrations ranged from just above the detection
limit to a maximum concentration of 5,600 parts per billion of
benzoic acid (Table 2).
Semivolatiles Detected in Vent Liquid
Powell Road Landfill
|Dames and Moore, 1990|
The distribution of semivolatile compounds in vent liquid samples was similar to that of VOCs. Concentrations were greatest in the southcentral, northeastern, and southeastern parts of PRL.
Vent liquid also contained high levels of a number of metals and
other inorganic chemicals (Table 3). Metal concentrations
represent total rather than dissolved content.
Metal and Inorganic Compound Analysis of Gas Vent Liquid
On-site at Powell Road Landfill
|Chemical||Concentration Range (ug/L)
|Dames and Moore, 1990|
Most of these metals and inorganics also occur naturally in the soil, groundwater, and to some extent, surface water. However, the concentrations of these metals and inorganics in vent liquids exceeded what would naturally occur in most media.
Surface leachate was sampled from one seep on the southwest corner of the landfill. This was the only seep which produced enough liquid to sample. This one leachate sample contained VOCs, semivolatile organic compounds, and metals (Table 4). The VOCs were also present in vent gas and liquids. The phthalate esters and naphthalene were also in vent liquid (Table 1). The metals and inorganic chemicals were all present in vent liquid samples (Table 3). Metal concentrations represent total rather than dissolved content.
Chemicals in On-Site Surface Leachate
Powell Road Landfill
|Bis (2-ethylhexyl) phthalate||88|
|Dames and Moore, 1990|
Ambient air samples were taken from eight locations within the fenced boundary of the landfill. Samples were taken on two days in October 1988 and may not represent normal day-to-day releases of chemicals from PRL.
On-site ambient air sampling revealed very low concentrations of
several VOCs close to the detection limits (Table 5). Those VOCs
present in ambient air were also detected in vent vapor, vent
liquid, and surface leachate.
On-site Ambient Air VOC Analysis
Powell Road Landfill
1 = U.S. EPA Reference Concentration
On-site surface soil samples were taken from 25 areas on the mounded portion and base of the landfill. There were only two surface samples taken from the mounded part of the landfill. Samples along the eastern - southeastern borders of the landfill contained semivolatile organic compounds. Polynuclear aromatic hydrocarbons (PAHs) were detected in one sample at 29,831 ug/kg. This sample location was next to the landfill access road along the eastern border of the landfill. PAHs were found above the detection limit in two different media, surface soil (one sample) and vent liquids.
Ten subsurface soil samples were taken from the base of the landfill mound. There were no subsurface soil samples taken directly from the landfill mound. One subsurface soil sample out of 10 had significant concentrations of semivolatiles (15,724 ug/kg). Butyl-benzyl phthalate was the main chemical in this sample taken from the northwest corner of PRL. This chemical was also found in one vent liquid sample, but at the northeast corner of the landfill.
Soil gas analysis measures the amount of chemicals which may be in the pore or open spaces in soils. Field measurements of methane and VOCs at PRL were taken along the northern and eastern borders of the landfill. Methane was measured with a combustible gas indicator and given as a percent methane. Combustible gas concentrations, as represented largely by methane, ranged from 11 percent to 62 percent, with two areas at relatively high levels. Field measurements of VOCs taken at 15 locations were generally below 2.0 ppm. There are, however, some limitations to using this type of field equipment for detailed measurement of soil gases.
Groundwater samples taken in December 1988 and April 1989 detected
VOCs. The 16 on-site monitoring wells are along the southern edge
of PRL (Figure 4). Contaminants were detected in seven of these
wells. The chemicals detected, range of concentrations, and
sampling years are in Table 6.
VOCs Detected in On-Site Groundwater
at Powell Road Landfill
NA = None Available
1 = Cancer Risk Evaluation Guide Calculated by ODH
|Dames and Moore, 1990|
Both the shallow and deep aquifers contained VOCs. The distribution of chemicals found in a number of monitoring wells varied from the first sampling round to the second. For example, in one well, vinyl chloride, chloroethane, and 1,2-dichloroethene were detected in 1988, but not in 1989. In addition, vinyl chloride was detected in two additional monitoring wells, but only in the second round of sampling. The wells with changes in chemical constituents are in the shallow aquifer.
Off site is outside of the PRL boundary, but within the Remedial Investigation study area (Figure 1). Off-site samples include ambient air (upwind and downwind), surface water, sediment from the Great Miami River, sediment samples from the intermittent stream, and groundwater.
Five VOCs were detected at very low concentrations in four ambient air samples collected downwind (north) of PRL. Maximum concentrations in samples collected during the 2-day October sampling period in 1988 were very close to the detection limits. Toluene, 1,1,1-trichloroethane, trichlorofluoromethane, and total xylene were also present in on-site ambient air samples. The VOCs present in downwind air were also present in vent vapor and vent liquid samples. Carbon tetrachloride was found only in one downwind air sample. Volatile organic compounds in upwind air samples were detected at very low levels during one day and were below detection the second day.
Sediment and surface water samples were taken from eight sample stations in the Great Miami River. Three sites were north of the landfill and not likely to be impacted by PRL. Only one chemical 4,6-Dinitro-2-methylphenol at 1,900 ug/kg, was found in a sediment sample. This sample was south of PRL on the northern edge of the river. This chemical was not found in a duplicate sample nor was it found in other media sampled.
Surface water samples from the Great Miami River were analyzed for VOCs, metals, and inorganic compounds. Metal concentrations represent total rather than dissolved content. There were no VOCs detected in these samples. Concentrations of metals and inorganics in upstream and downstream samples did not differ and may reflect regional characteristics of surface water.
Off-site groundwater sample areas are north and south of the site
(Figure 1, Appendix A). Twenty-one monitoring wells were sampled
as part of the groundwater investigation. Samples were taken from
the deep and shallow aquifers. There were no VOCs detected from
the area north of PRL (Figure 1, Appendix A). Data obtained in the
Remedial Investigation (Table 7) and other data (Tables 8 and 9)
have detected a pocket of contamination south of the community of
Eldorado Plat, located in the area east of Sunny Acres Mobile Home
Park and north of Needmore Road (Figures 1 and 4, Appendix A).
Off-site Groundwater Data
from Monitoring Wells
|*Also present in on-site groundwater.
1 = U.S. EPA Maximum Contaminant Level
|Dames and Moore, 1990|
Groundwater contamination off-site is present in both the shallow and deep aquifers. Both aquifers on-site also contained chemicals. However, only one of these compounds (1,2-dichloroethene) was present in on-site groundwater. Trichloroethene was present in on-site vent vapor and ambient air, but not in groundwater.
A total of 29 samples of residential wells and public water
supplies were taken in 1988 and 1989 as part of the remedial
investigation. These residential wells were north of PRL, south of
PRL at Eldorado Plat, and north of Needmore Road (in the southern
part of the study area). There were two samples out of the 29 with
VOCs above the detection limit. The two samples were from the
abandoned well at Sunny Acres Mobile Home Park and one well from
OSWC's well field (Table 8). Sunny Acres was placed on Dayton city water in 1984 and VOC strippers are in place on the OSWC wells.
Recent sampling (OSWC, personal communications, 1990) indicates
continued contamination of the raw groundwater with organic
compounds, with 140 ppb DCE in Well #5 and 4-5 ppb vinyl chloride
in Well #4). Wells and finished water at the well field currently
are regularly sampled on a monthly basis to insure water quality is
maintained below the U.S.EPA MCLs. There were no site-related
chemicals present in the samples taken north of PRL or other
private wells sampled.
Off-Site Public Water Wells
VOC Results from Areas South of Powell Road Landfill
|1 = U.S. EPA Maximum Contaminant Level
2 = ATSDR EMEG
ND = Chemical Not Detected
|CH2M Hill, 1986|
VOCs were first observed in a small sample of the Miami well field production wells as early as 1983 (CH2M Hill, 1986). Expanded sampling outside of the well field by the OEPA, U.S.EPA, and the city of Dayton discovered additional contamination. Sampling discovered VOCs in wells from the Sunny Acres Mobile Home Park, a gas station, a golf course, and other private wells (Table 9). These areas are south of Powell Road Landfill and the OEPA does not consider Powell Road Landfill to be the source of contamination in these other areas.
There were other private wells sampled from 1983 through 1985 which
did not show any chemical contamination. These wells were both
north and south of the site.
Concentration of VOCs in Off-Site Groundwater
from Previous Sampling South of Powell Road Landfill
DCA = 1,1-Dichloroethane
DCE = 1,2-Dichloroethene
ND = Chemical Not Detected
NA = None Available
1 = U.S.EPA Maximum Contaminant Level
2 = Comparison Value Calculated by ODH
Other data collected by the city of Dayton in 1985 during the drilling of 40 monitoring wells, indicated additional groundwater contamination. VOCs were detected in two of the 40 wells sampled. These two wells are located in the South Well field (south west of PRL in area of Kitty Hawk Golf Course (Figure 1, Appendix A). Additional data collected by the city of Dayton detected low levels of VOCs from two wells in the proposed Rip Rap Island area (Miami North Well Field).
Third and fourth rounds of groundwater sampling took place in November, 1990 and February, 1991, respectively. Forty-six wells, including eight new monitoring wells, were sampled in the round 3 sampling. The eight new wells included MW16A, MW16B, MW16C, and replacement well MW4BR, located along the southern margin of the landfill, plus monitoring wells MW13C, MW14B, MW15B, and MW15C, located south of the Miami River, along the northern edge of Eldorado Plat (see Figure 1, Appendix A). There were quality control problems with the third round sampling and the results were discarded (Eagon & Associates, 1991).
The same 46 wells, including two residential wells in the Eldorado Plat area, were resampled in February 1991. The results of this round of sampling is presented in Table 10.
Fourth Round of Groundwater Monitoring-1991
Powell Road Landfill
|1,2 Dichloroethene||ND-220||70 - 1003|
NA = None Available
1 = Cancer Risk Evaluation Guide Calculated by ODH
2 = Comparison Value Calculated by ODH
3 = U.S.EPA Maximum Contaminant Level
These VOCs, with the exception of trichloroethene, were detected in the previous rounds of groundwater sampling (Table 6). VOCs were detected in monitoring wells screened in the shallow aquifer (depths 7-17 ft), located along the southern margin of the landfill. This is consistent with previous sampling rounds (1988, 1989, SCA, Inc, 1990). The highest concentrations of 1,1 dichloroethane were recorded for wells MW04B and MW4BR, both screened in the deep aquifer at depths of 57-62 ft. The highest concentrations of DCE and TCE were detected in monitoring wells screened in the deep aquifer in the vicinity of Needmore Road, southeast of the PRL site and south of Eldorado Plat. This area has recorded consistently high levels of TCE and DCE in deep aquifer groundwater since 1984 (SCA Inc., 1990). Probably the most significant new information provided by the round four sampling was the occurrence of low levels of TCE and DCE in monitoring wells MW13B and MW15B, both screened in the deep aquifer (depths of 62-67 ft and 43-48 ft, respectively) and both on the south side of the Miami River, along the northern edge of Eldorado Plat. Residents in Eldorado Plat use private wells screened in the deep aquifer for their water supply.
The ODH obtained the Toxic Chemical Release Inventory (TRI) data for the city of Huber Heights from the OEPA Air Pollution Control to identify possible facilities that could contribute to the contamination near Powell Road Landfill. The TRI was developed by the U.S.EPA from the chemical release information provided by certain industries. The TRI information for Huber Heights indicated that one facility released tetrachloroethene into the air. This chemical was not detected in the off-site monitoring data at the site.
In preparing this public health assessment, ATSDR and the ODH relied on the information provided in the referenced documents and assumes that adequate quality assurance and quality control measures were followed with regard to chain-of-custody, laboratory procedures, and data reporting. The validity of the analysis and conclusions drawn for this public health assessment is determined by the availability and reliability of the referenced information.
There are no physical hazards associated with the Powell Road Landfill. The presence of methane in soil gas may represent a hazard to the two residents along the northern boundary of the landfill due to the flammibility of the gas. Field measurements of methane and VOCs at PRL were taken along the northern and eastern borders of the landfill. Methane alarms have been placed in these two homes.
Chemicals can be present in gaps and pores of soils as gases. Soil
gas analysis was not adequate to determine the extent of soil gas
contamination. Chemicals in soil can migrate through the soil to
the north, east, and west of the site. The Great Miami River and
the distance to residential areas to the south would tend to
inhibit soil gas migration.
Site investigations at PRL revealed site-related chemicals in gas vent vapor and liquid, leachate, ambient air, soil, and groundwater. Environmental pathways and human exposure pathways are discussed in the following sections.
VOCs are mobile chemicals prone to transport from one media to another. The physicochemical nature of VOCs enables them to move easily into air (volatilization), into surface water, or groundwater. Once in the air, VOCs in general, do not remain for long periods of time. Vinyl chloride, for example, has a half-life in the atmosphere of approximately two days. Many of these chemicals, such as chloroethane and benzene, are subject to degradation when present in the atmosphere. VOCs in surface water tend to volatilize into the air where they degrade. VOCs are fairly persistent in groundwater.
Semivolatile organic compounds are not as mobile as VOCs. They would not readily move through soil into the groundwater. Under conditions when water inundates the landfill, they may enter groundwater attached to soil particles. They would, however, remain adsorbed to soil particles. Semivolatiles may be transported by adsorption to dust.
Ambient air may be an important pathway for chemical transportation from PRL. VOCs were detected downwind from the landfill. The presence of these contaminants in downwind samples (at very low concentrations) may be due to transport from PRL. VOCs in vent liquid may be a continuous source of chemicals. Release of VOCs to ambient air may increase during remediation or if the landfill cap integrity is adversely affected.
Groundwater is an important pathway for contaminant migration at PRL. Chemicals were discovered in groundwater both on site and off site. Off-site contamination detected in the remedial investigation was centered in the extreme southern part of the study area (Sunny Acres, Figure 1, Appendix A). There are also historical data indicating other areas of contamination (Table 9). Groundwater along the southern edge of the landfill contained VOCs. While the two residential wells in Eldorado Plat that were sampled in round 4 (1991) showed no contaminants (Eagon & Associates, 1991 ), the occurrence of VOCs in the 1991 sampling of monitoring wells 400 to 600 feet north and northwest of the nearest homes, indicates that site-related chemicals are moving into the deep aquifer under the site and are moving towards residential wells in Eldorado Plat.
VOCs in groundwater are fairly persistent and there is very little opportunity for losses from the system. In general, VOCs can be fairly water soluble and will travel great distances in groundwater. These types of compounds can undergo degradation, changing from one compound to another. The degradation of tetrachloroethene to trichloroethene, to 1,1- Dichloroethene and finally to vinyl chloride, is an example of pathway degradation. This type of pathway degradation creates new chemicals in a medium, such as groundwater.
Powell Road Landfill overlies an area of permeable sand and gravel outwash deposits. Groundwater in the study area is present as one or two aquifer systems depending on the presence of a confining bed. At the south end of the PRL site, this sand and gravel aquifer is divided into shallow and deep aquifers by a layer of less permeable, clay-rich till, up to 20 feet thick (Figure 5, Appendix A). This layer of till can act as an effective barrier to the downward migration of contaminants to the deep portion of the aquifer, however, it is absent directly under the landfill itself. At the landfill site, the water table occurs from 1 to 10 feet below the floodplain surface.
The presence or absence of the till-confining bed can have a significant effect on contaminant transport in groundwater. In those areas where the till zone is present, the upper aquifer is highly susceptible to downward movement of contaminants. However, the confining bed does limit further vertical movement of contaminants from the shallow aquifer into the deep aquifer (CH2M Hill, 1986). The absence of the confining bed under most of PRL may allow chemicals to move from the landfill into the aquifer. This enhances the migration of chemicals to both the shallow and deep aquifers.
There are other factors which may affect chemical transport in the groundwater. The presence of a groundwater divide, south of the landfill and extensive pumping of groundwater may also impact transport of site-related chemicals in the groundwater. The bulk of the groundwater flow under the landfill moves from the northwest to the southeast due to capture by the Ohio Suburban Well Field. Travel time from the PRL site to the Ohio Suburban Well Field is estimated to range from one to five years depending on local conditions. Proposed development of the Rip Rap Island area (Miami North Well Field), west of the landfill, as a municipal well field by the city of Dayton would further disrupt groundwater flow in the area. It could divert flow under the PRL site from the southeast towards the Ohio Suburban Well Field, to the west into the proposed new Dayton well field. Without any form of remediation, travel times to the new well field from PRL would be extremely short (CH2M Hill, 1986). Extensive pumping of groundwater in the area surrounding PRL may alter the travel time and direction of contaminatead groundwater. The presence of chemicals in groundwater along the southern edge of PRL follow groundwater flow. Presently, contaminants are moving north to south or south-east. The current direction of contaminant migration is important when considering future migration of contamination in the groundwater.
The flow of groundwater in the area of PRL may be affected by the aquifer recharge and the Great Miami River. Aquifer recharge includes precipitation, recharge from Great Miami River, and inflow from upland areas. Significant recharge to the groundwater from the surface can enhance infiltration of contaminants through PRL into the aquifer. Recharge from the Great Miami River may, however, aid in dilution of contaminants in the groundwater.
There were also differences in which chemicals were detected in the two aquifers. Chemicals were not always present in both aquifers on site and off site. On-site groundwater contamination, with the exception of one sample, was found in the shallow aquifer. In off-site groundwater, 1,2-Dichloroethene and trichloroethene were found in deep aquifer samples (Table 7).
Changes in chemical detection may represent changes in concentration or (hot spots) of landfill constituents. The drought of 1988 throughout most of the region may also have had an impact on chemical detection, because of changes in levels of groundwater. Groundwater inundates the landfill during periods of high water which may affect movement and dilution of chemicals from the landfill (Dames and Moore, 1990).
Vent vapor and vent liquid analysis provided additional information to determine future contamination scenarios, in as much as samples may be representative of what chemicals are present at PRL. Vent liquid may represent actual landfill liquids or vapors which were released from the landfill and condensed to liquid form back into the vent. Chemicals present in vent liquids, especially VOCs, may be free to move into groundwater and ambient air. VOCs in groundwater on site and to some extent, off site, were also present in vent samples. There were some VOCs consistently found in vent samples (liquid and vapor) and groundwater. The common occurrence of chemicals in vent vapor, vent liquid, groundwater and air, may be indicative of transport of landfill materials from PRL.
Volatile organic compounds were present at very low levels in on-site ambient air and in downwind air samples. If remedial activities on the site alter the landfill cap, the volume of compounds released could be significant. Under current circumstances, ambient air is not a significant route of human exposure to the general public.
Exposure to leachate does not represent a significant exposure pathway, as there is only one seep located at the landfill.
Groundwater in off-site residential wells contained VOCs. The wells
with contamination have been abandoned. Exposure which may have
occurred has ceased. Sunny Acres Mobile Home Park was placed on
Dayton City water in 1984 and exposure has ceased. Sampling in
1985 by the U.S EPA detected very low levels of VOCs in residential
wells in the Eldorado Plat area. Three of these 4 wells were
abandoned in 1987 and 1988, and new, deeper wells were drilled.
Groundwater sampled from monitoring wells off site also contained
VOCs. Wells in the Miami and OSWC wells are equipped with air-strippers to remove any VOCs in the water and any ongoing exposure
has ceased. The human exposure pathways associated with
contaminated groundwater are presented in Table 10. These human
exposure pathways include possible past exposure and potential
exposures, provided additional chemicals migrated to off-site
drinking water supplies.
Human Exposure Pathways
from Powell Road Landfill
|Chemical||Route of Exposure
*Humans can inhale vapors released from contaminated household
water. On-site remediation workers may be exposed to airborne
contaminants if landfill cap integrity is adversely affected.
Environmental investigations in the area of PRL discovered site-related chemicals in the groundwater. There is a potential for humans to be exposed to site-related chemicals. The full scope of the contamination was discussed in the Environmental Contamination and Other Hazards Section and the Pathways Section. Data do not show that exposure to humans is now occurring, but it may occur in the future.
Workers on the site may be exposed to VOCs in ambient air. This may be significant if the release of volatiles greatly increases during remedial activities. Because of the extremely low concentrations, the general public should not be at risk from exposure to chemicals in the air.
The following discussion reviews the available data about the chemicals of concern that are in the pathways of human exposure at the Powell Road Landfill. Exposures may have occurred in the past and may occur in the future. There is often little information available about the health effects of exposures to the concentrations of the chemicals found at PRL. Most of the studies of human exposure use information from industrial exposures, where the exposure levels are much higher than those that may occur from chemicals at PRL. Industrial exposure data normally does not include precise information about the dose, the purity of the compounds, interactions, and the duration of the exposure. With the acknowledgement of these limitations, pertinent human data will be used in this section. Although animals do not necessarily have the same responses that humans show when exposed to toxic substances, animal experiments can be conducted under carefully controlled dosages and time periods. Accordingly, when human information is unavailable, pertinent animal data will be incorporated into this section. Often the essential toxicological properties of the compounds discussed have not been adequately investigated.
In determining how toxic a chemical is, it is important to evaluate not only whether it is in a human exposure pathway, but how much of it is present. The toxicity assessment of a chemical is made by determining its adverse effects in organisms (generally animals and people) and how much of it is needed to produce these effects. A chief objective of a toxicity assessment is to find the lowest dose, which can cause illness. This information is obtained by a dose-response curve, which shows the relationship between the dose and the response. As the dose increases, at some level above 0, the response (toxic reaction) becomes apparent and then increases. This information is shown as a no-observed-adverse-effects-level, NOAEL, (the highest dosage at which no adverse effects are observed) and the low-observed-adverse-effects-level, LOAEL, (the lowest dosage at which toxic reactions begin to be observed).
Vinyl chloride levels in groundwater at PRL exceeded the Maximum Contaminant Level and other health guidelines. Inhalation exposure to high levels of vinyl chloride in occupational settings can cause liver and possibly brain cancer in some workers. Vinyl chloride is classified as a known human carcinogen. There is very little data available on potential adverse human health effects from ingestion of vinyl chloride. If a person were to drink water containing vinyl chloride at levels found in on-site groundwater, the risk of developing cancer from this exposure would be increased. In studies using rats, oral doses of vinyl chloride increased the incidence of tumors and/or liver cancer. For the rat, the liver is the target organ for both carcinogenic and noncarcinogenic effects by inhalation and oral exposure. There were no data available for dermal exposure to vinyl chloride.
The toxicological data for chloroethane is extremely limited. Human inhalation exposure to 13,000 ppm (a higher exposure level than would be expected at the Powell Landfill) results in slight symptoms of poisoning (Torkelson and Rowe, 1981). The Federal Standard and the Time Weighted Average permissible exposure limits in air is 1000 ppm or 2,600 mg/m3 (Sittig, 1985). Long term inhalation exposure to high concentrations has caused cancer in rats and female mice (Torkelson and Rowe, 1981). Dogs exposed to high doses of chloroethane vapors suffered respiratory effects and cardiac depression. There are no data on health effects from oral or dermal exposure. Chloroethane at one time was used as an anesthetic. It is not known what health effects if any, could develop if a person were to be exposed to levels of chloroethane found in on-site groundwater.
The highest concentration of this chemical in groundwater at PRL was 48 ppb, well below the MCL, however, the potential exists for levels to increase. Inhaling high levels of 1,1,1-trichloroethane can cause irritation of the respiratory tract, organ damage and depression of the central nervous system. Exposure of this type also resulted in dizziness and eye irritation. Depression of the nervous system appears to be consistent with exposure to this compound. Mice exposed to relatively high doses of 1,1,1-trichloroethane experienced increases in liver weight and triglycerides and alterations in liver cells. Inhalation was the most common route of exposure studied, therefore, data on oral and dermal exposure is limited. Low levels of 1,1,1-trichloroethane, in drinking water in combination with other VOCs, have been associated with congenital heart defects (Bove et al., 1992). However, this study would not provide sufficient evidence to show that 1,1,1-trichloroethane causes congenital heart defects, because the people were exposed to more than one chemical and it is difficult to determine which chemical would be associated with the congenital heart defects. Moreover, information on other risk factors for congenital heart defects was not included in this study.
There were no human data available for acute or long-term exposure to 1,2-dichloroethene (DCE). DCE is found in two chemical forms, a cis and a trans isomer (or form). The DCE measurements at the Powell Landfill did not distinguish these forms. The concentration range of DCE measured in off-site groundwater ranged from 12 to 520 ppb. If a person were to be exposed to groundwater with DCE at the concentrations found on site, the estimated dose would be close to the level of concern.
Low concentrations of DCE in drinking water, in combination with other VOCs, have been associated with congenital mouth and nervous system defects (Bove et al., 1992), and childhood leukemia, deaths around the time of birth, childhood disorders, congenital abnormalities, recurrent infections, and with heart disease (Lagakos, 1986) (Byers et al., 1988) (Goldberg, 1990). These studies, however, do not provide sufficient evidence that DCE causes these adverse health effects, because the people were simultaneously exposed to more than one chemical. It is difficult to determine which chemical or combination of chemicals would be associated with the various adverse effects. Moreover, information on other risk factors for these adverse effects was not included in these studies.
An animal study found that no adverse effects were observed in rats, rabbits, guinea pigs, and dogs inhaling 1000 ppm for seven hrs/day, five days/ week for six months. The lungs and liver were affected and the leukocyte count was decreased in rats exposed to a relatively high dose for an intermediate period of time(Torkelson and Rowe, 1981). Long-term inhalation exposures resulted in effects on the liver. DCE does not appear to be carcinogenic. In rats, DCE was toxic when given orally. No data were available for dermal exposure to either animals or humans.
The levels of TCE found in off-site groundwater ranged from 2.0 to 508 ppb. The first symptoms in occupational settings begin to occur around 30 ppm.
Trichloroethene, in drinking water in combination with other VOCs, has been associated with congenital mouth and nervous system defects and very low birthweight (Bove et al., 1992), and childhood leukemia, deaths around the time of birth, childhood disorders, and congenital abnormalities recurrent infections, and with heart disease (Lagakos, 1986)(Byers et al., 1988) (Goldberg, 1990). These studies, however, did not provide sufficient evidence that TCE causes these adverse health effects, because the people were exposed to more than one chemical simultaneously. It is difficult to determine which chemical would be associated with the various adverse effects. In addition, information on other risk factors for these adverse effects was not included in this study. The data on carcinogenicity in humans exposed through inhalation and oral ingestion are limited. TCE is classified as a probable human carcinogen. The levels in groundwater at PRL are generally low, but there would be a slight increased cancer risk if a person were consuming water contaminated with TCE at the levels found on site. Mice dermally exposed to TCE did not develop tumors.
Long term inhalation and ingestion exposure studies in mice and rats also resulted in central nervous system effects. In addition, there were liver and kidney damage, effects on the blood, and tumors of the liver, kidney, and male sex organs.
ODH must depend on previously gathered data to perform a public health assessment. The only readily accessible data are for cancer mortality for Huber Heights, Montgomery County and the state of Ohio. There are some limitations that must be considered when cancer mortality data are evaluated. The number of people who may be affected by chemicals at the site are usually smaller than the groups of people for which we have health outcome data. When this occurs, the illnesses of the smaller group may not be distinguishable from the larger groups' rates. Death certificates only contain those who have died of cancer and not the persons who have been diagnosed with cancer. Mortality records such as the Ohio Death Certificates are also subject to the decisions made by the recording physician who must differentiate between "immediate", "contributing", and "underlying" causes of death. Cancer mortality statistics must therefore, be interpreted with caution.
The age adjusted rate for all cancer in Ohio from 1986-1988 was
207.5 deaths per 100,000 people; for Montgomery County, the rate
was 212.5 (Table 12). Overall, Montgomery County ranks in the top
25th percentile of Ohio Counties for all cancer deaths for this
time period (Cancer Mortality Rates in Ohio, 1986-1988, ODH). When
comparing the overall cancer rate there is little difference
between the areas. There is no difference in cancer rates between
Huber Heights and the other areas (Table 12).
Cancer Mortality Evaluation for
Huber Heights, Dayton, Montgomery County, Ohio
|CANCER DEATH COMPARISON|
|ANNUAL AGE ADJUSTED RATE PER 100,000 PEOPLE|
2 = Montgomery County and Ohio the period includes 1986-1988.
3 = The Other Category includes cancers which are not listed separately in Table 12, such as oral, cervical, skin, bone, stomach, etc.
1) Are people at risk from the toxic waste and chemicals at the landfill?
Response: Yes people were at risk and may be a risk in the future from the chemicals at the landfill. Hazardous waste sites are placed on the Superfund, National Priorities List (NPL) because of the potential for risk to human health. This public health assessment has concluded that some residents south of the landfill may have been exposed to VOCs through the consumption of contaminated groundwater. There is also a potential for people to be exposed in the future if contaminated groundwater reaches other private wells.
2) How was this allowed to happen? How can we keep this from happening in the future?
Response: Unfortunately, problems such as these are a terrible legacy of our industrial society. Prior to the early 1970's, the disposal of hazardous waste was minimally regulated. Until the discovery of the environmental problems that DDT caused, very little was known about the problems associated with hazardous waste. Today there are strict regulations which restrict hazardous waste disposal and use. In addition, many companies are working to limit their production of hazardous waste.
3) What type(s) of chemicals are there at the landfill?
Response: The types of chemicals included semivolatiles (PAHs, phthalate esters, phenol), VOCs (vinyl chloride, trichloroethene) and metals. Additional information is presented in the Data Tables in the Environmental Contamination Section of this public health assessment.
4) Have there been studies done so far on the health statistics of people in the area?
Response: To date, the Ohio Department of Health has evaluated the cancer mortality data for Huber Heights, Dayton, and Montgomery County. This information is discussed in the Health Outcome Data Evaluation Section. County-wide data are not relevant if a smaller area is being studied. The data and information developed in the Powell Road Landfill Public Health Assessment have been evaluated for appropriate follow-up health activities. The following follow-up actions may also be considered:
- Inclusion in the TCE subregistry;
- A disease and symptom prevalence study; and
- Development of a voluntary disease and symptom tracking system.
If data become available suggesting that humans are currently being exposed to levels of hazardous substances that may adversely impact human health, ATSDR will reevaluate this site for additional follow-up public health actions.
5) What health problems have resulted from exposure to VOCs?
Response: There are very little toxicological data on adverse human health effects of VOC exposure through the consumption of contaminated water. Certain birth defects such as neural tube defects, oral clefts, cardiac defects, and very low birth weight have been associated with contaminants in groundwater. These contaminants included, trichloroethene, carbon tetrachloride, tetrachloroethene, 1,2-dichloroethane, 1,1,1-trichloroethane, dichloroethenes, and trihalomethanes. These studies involved more than one chemical exposure and it is difficult to determine which chemical is associated with which adverse birth outcome. In addition, in this study there was no information on other risk factors such as maternal cigarette and alcohol consumption, occupational exposures, illnesses, and medications (Bove, et al. 1992). These other factors have also been linked with birth defects in children born to mothers with these risk factors. These studies do not provide sufficient evidence to make the claim that these contaminants cause adverse reproductive outcomes (Bove et al., 1992). Other studies have found an association with congenital cardiac malformations and drinking water contaminants (Goldberg, S. 1990). One must keep in mind that any adverse effects depend on a number of pieces of information such as the specific chemical, the dose, and the route of exposure. In general, the liver, kidneys, central nervous system, and lungs are the target organs for those VOCs present in groundwater at PRL. Vinyl chloride is classified as a human carcinogen and trichloroethene is classified as a probable human carcinogen.
6) Is there evidence of effects on offspring from exposure to VOCs?
Response: Certain birth defects such as neural tube defects, oral clefts, cardiac defects, very low birth weight have been associated with contaminants in groundwater. These contaminants included, trichloroethene, carbon tetrachloride, tetrachloroethene, 1,2-dichloroethane, 1,1,1-trichloroethane, dichloroethenes, and trihalomethanes. These studies involved more than one chemical exposure and it is difficult to determine which chemical is associated with which adverse birth outcome. In addition, in this study there was no information on other risk factors such as maternal cigarette and alcohol consumption, occupational exposures, illnesses, and medications (Bove, et al. 1992). These other factors have also been linked with birth defects in children born to mothers with these risk factors. These studies do not provide sufficient evidence to make the claim that these contaminants cause adverse reproductive outcomes (Bove et al., 1992). Other studies have found an association with congenital cardiac malformations and drinking water contaminants (Goldberg, 1990).
7) I am interested in the mode of exposure because I live close to the landfill. We have lost trees along the property line.
Response: At this time, it appears as though the most likely route of human exposure to site-related chemicals is through contaminated drinking water supplies. Private wells in the area south of the site along Needmore Road contained VOCs. The OEPA does not consider the Needmore road plume to be linked to Powell Road Landfill. Chemicals can also migrate through soils. We have recommended that the soil gas survey be expanded in order to determine if chemicals are migrating away from the site through the soil.
8) I am concerned about contaminants in the water, land, and air.
Response: The chemicals of concern in groundwater are primarily VOCs. Most of the contamination is on site, but there is some indication that chemicals have moved off site. Soils and air are minimally contaminated at PRL.
9) I am concerned about my children. We have one child with increased sensitivities and another child with respiratory problems. One child was born while PRL was in operation and developed asthma; the child born after it was closed down did not have asthma.
Response: Data reviewed for this health assessment indicated that the most likely route of exposure was through the consumption of contaminated water in the southern most part of the RI study area. If you do not live in this area, it is not likely that you would have been exposed to site-related chemicals. The following includes a discussion of asthma. Asthma is a common condition. Half of all cases occur in children under age 10; in this age group, asthma affects twice as many boys as girls. A hereditary predisposition is indicated; about one third of all asthmatics share the disease with at least one member of their immediate family and three fourths of the children with two asthmatic parents also have asthma. Exposure to tobacco smoke has also been linked with an increased incidence of asthma. In fact, passive smoking may cause up to 100,000 new cases of pediatric asthma in the United States each year.
10) Concerned about the methane at the landfill.
Response: We have recommended additional soil gas sampling at the landfill. Currently, there are 10 passive vents to vent excess gas from the landfill. In addition, there are methane monitors in the two homes closest to the landfill that are equipped with alarms. If methane were to migrate from the landfill into homes near the site, it would likely be detected at these two homes. There are also plans to incorporate a more active venting system for the site remediation.
11) Concerned about the new Dayton wells pulling contaminants to our well.
Response: If the proposed city of Dayton well field along Rip Rap Road goes into operation, it will have the potential to pull groundwater contaminants from the PRL site west towards the well field. Residential wells in the vicinity of PRL are to the north, east, and southeast of the site and may be affected with a lessening of the potential for site-related contaminants to enter these residential wells.
12) There are a number of people in the area that have died from cancer.
Response: There are approximately 49,000 new cases of cancer diagnosed in Ohio each year while about 24,000 Ohioans will die as a direct result of cancer. Approximately one person in three born in 1990 will develop cancer in their lifetime. The age adjusted rate for all cancer in Ohio from 1986-1988 was 207.5 deaths per 100,000 people; for Montgomery County, the rate was 212.5. Overall, Montgomery County ranks in the top 25th percentile of Ohio Counties for all cancer deaths for this time period (Cancer Mortality Rates in Ohio, 1986-1988, ODH). There is little difference in the overall rate when comparing Huber Heights with the nearby metropolitan city of Dayton.
13) I am a nurse and see a lot of children with upper airway problems and increased incidence of asthma in the last 10 years. What is happening to cause children to have these allergies?
Response: Data reviewed for this health assessment indicated that the most likely route of exposure was through the consumption of contaminated water in the southern most part of the RI study area. If you do not live in this area, it is not likely that a large number of these children would have been exposed to site-related chemicals. Upper airway problems can include asthma, colds, and exposure to tobacco smoke. Asthma is a common condition. Half of all cases occur in children under age 10; in this age group, asthma affects twice as many boys as girls. A hereditary predisposition is indicated; about one third of all asthmatics share the disease with at least one member of their immediate family and three fourths of the children with two asthmatic parents also have asthma. Exposure to tobacco smoke has also been linked with an increased incidence of asthma. In fact, passive smoking may cause up to 100,000 new cases of pediatric asthma in the United States each year.
14) Would we consider doing biological testing of people?
Response: At this time, we do not think that biological testing of people would provide accurate information in the determination of possible exposures. As mentioned in concern #1, the human exposure pathway is the consumption of groundwater containing VOCs. Because most people already have body burdens of VOCs, biological monitoring would not really tell us any more than we know now. We would be unable to determine if any detected VOCs resulted from exposure to site-related chemicals or from other background exposures.
15) Concerned about the river flooding into the landfill.
Response: We have discussed the possibility of flooding with the Ohio EPA site coordinator. They are also concerned about this issue, however, as of now there are no answers. We hope to address this issue in discussions with the Ohio EPA.
16) The landfill sits on the water supply and am concerned about the water supply.
Response: As of the time of the Remedial Investigation of the PRL site (1988-1991), groundwater contamination directly related to the site was mostly limited to the immediate vicinity of the site. The City of Dayton Miami South well field and the Ohio Suburban Water Company well field are both regularly monitored for chemical contaminants and have water treatment equipment (Air-strippers and activated carbon filtration systems) already in-place in case contamination does occur.
17) Her grandmother lives in Sunny Acres trailer park. Was it safe there? Was her grandmother exposed to contaminated drinking water? What could TCE/DCE do to her grandmother? Is her grandmother's water safe now?
Response: Sampling outside of the Miami well field by the Ohio EPA, U.S.EPA, and the city of Dayton in 1984 discovered VOCs in wells from the Sunny Acres Mobile Home Park. Trichloroethene (TCE) and 1,2 dichloroethene (DCE) are present in the deep aquifer in the Needmore Road area. Sunny Acres Mobile Home Park was placed on Dayton City water in 1984 and exposure has ceased. We do not know how long the exposure may have occurred. In laboratory animals, these chemicals affected the lungs, liver, and the central nervous system. It is not known whether exposure has the same effects in humans. TCE is classified as a probable human carcinogen. The levels of TCE in groundwater at PRL are generally low, but may increase one's cancer risk if water contaminated with TCE was consumed.
18) Is it safe in Eldorado Plat? Is the water contaminated?
Response: Eldorado Plat is located immediately southeast and down-gradient of the PRL site. Residents of this community use private wells as their water supply. Very low levels of volatile organic compounds (VOCs) were detected in four residential wells in Eldorado Plat in 1984 and 1985. These levels were below health concern levels. Additional sampling of wells in the area (1991) has not detected any chemical contaminants in residential wells. However, new groundwater testing in the area (1991, Appendix C) has shown low-levels of possible site-related contaminants in monitoring wells drilled in the deep aquifer in the northern and northwestern portions of the community on the south side of the Miami River. There may be a potential to affect the quality of the well water used by residents of this community. We have recommended that groundwater in the area of Powell Road Landfill continue to be monitored.
19) Could site contaminants in groundwater move their way? What would the effects be if EPA decides to clean up PRL via Pump & Treat?
Response: Groundwater flow in the vicinity of the PRL site is to the south and southeast. Site-related contaminants at PRL are currently restricted to areas along the western and southern boundaries of the site and the adjacent northern edge of Eldorado Plat. Potential exposure to site-related contaminants is dependent on the location of the resident's well relative to the PRL site.
It is hard to predict the possible effects of a Pump and Treat system at the PRL site in terms of its impact on the local groundwater system. Pumping on site may locally disturb watertable levels and have a minor effect on local groundwater flow directions. The observed effects are a function of how much groundwater is pumped, local groundwater levels (controlled by rainfall, recharge, pumping), and the proximity of the resident's well to the PRL site.
20) Was the contamination along Needmore Road the result of the landfill?
Response: It remains an unresolved question as to whether the contamination of the groundwater aquifer in the Needmore Road area is the result of contamination from the PRL site. The OEPA has concluded that the contamination in this area is not directly related to the site. Trichloroethene (TCE) and 1,2 dichloroethene (DCE) are present in the deep aquifer in the Needmore Road area. In the past, contaminants at the PRL site have consisted of dichloroethane (DCA), DCE, trichloroethane, chloroethane, and vinyl chloride. These contaminants are present in the shallow aquifer.
21) Was the water in the Huber Heights OSWC well field contaminated with chemicals?
Response: The groundwater in the vicinity of the Ohio Suburban Water Company well field is contaminated by organic compounds, including TCE, DCE, and vinyl chloride. Well #5 in the OSWC well field was shut down in 1981 and Well #4 was taken out of service in 1988, both the result of chemical contamination. A water treatment system to remove these organic chemicals from the raw water (air stripper) was installed in 1990. All wells have been returned to service. Recent sampling (OSWC, personal communications, 1990) indicates continued contamination of the raw groundwater with organic compounds, with 140 ppb DCE in Well #5 and 4-5 ppb vinyl chloride in Well #4). Wells and finished water at the well field currently are regularly sampled on a monthly basis to insure water quality is maintained below the U.S.EPA drinking water standards.
22) Could residents' cattle be contaminated?
Response: We do not believe that farm animals in the area have been exposed to any chemicals of concern. At this time, chemicals have migrated off site in the groundwater. In order for cattle to be exposed they would have to drink contaminated groundwater and data does not indicate that any private wells currently in use contain site-related chemicals.
23) Could residents' property and wells be contaminated by site- related pollutants?
Response: The potential for off-site property and well water to be affected by contamination coming from the PRL site is dependent upon the resident's location relative to the site. As indicated previously, private wells along the northern edge of Eldorado Plat face the greatest threat of contamination by PRL-related chemical contaminants. There is no evidence to suggest other off-site movement of contaminants via surface water run-off, wind-blown dust, or air-borne gases. There has been some accumulation of methane gas in soils at the north end of the landfill, south of Powell Road. Currently, there is no evidence that methane gas has moved from the landfill to off-site areas.
24) Concern over the 8-10 people living on Powell Road immediately east of the landfill who had died of cancer. One of the women who's husband died of cancer said that before her husband died, he had intense skin itching. She thought she was beginning to experience these symptoms also.
Response: On average, one out of three people will get cancer and one out of five will die from it. Without the appropriate demographics (e.g., age, race, sex), it is not possible to determine if these deaths exceed the national or local levels. Skin itching is a symptom which often accompanies cancer, especially lymphomas.
25) Concerns that lead paint may have been dumped on the site.
Response: Lead was included in the environmental monitoring and analysis at PRL. Lead is present in vent gas liquid and surface leachate. We do not believe that people are currently being exposed to lead from the site.
26) People were still using the site after it was closed.
Response: We are not aware of site use other than during site investigations. The landfill was closed and capped in 1985. Further use for disposal would have stopped once the landfill was capped.
27) Trucks traveling to the site were leaking wastes along the roads.
Response: This type of information with details about where this occurred should be addressed to the Ohio EPA.
28) Would there be further contamination if the site is disturbed?
Response: The analysis of vent vapors and liquids detected the presence of VOCS, semivolatiles, and metals. VOCs could be released into the surrounding air if the landfill cap was significantly disturbed. Under these circumstances those at risk would be site workers.
29) Residents are under a lot of stress.
Response: We are aware that individuals in the community have many concerns about possible exposures to site-related chemicals. As discussed previously, the most likely route of exposure was through the consumption of contaminated groundwater. One must keep in mind that exposure does not automatically mean that there will be health problems. However, a symptom and disease prevalence study and the inclusion of the residents in a voluntary residents' tracking system were indicated as part of the ATSDR Health Activities Recommendation Panel review.
30) How dangerous are gases released from the landfill? How much dilution of gases occurs when released?
Response: Gases can be released from the landfill through the passive vents at the site. The analysis of vent vapors and liquids detected the presence of VOCS, semivolatiles, and metals. VOCs would be the type of chemical to be released through the vents. We would expect these released VOCs to be diluted and broken down in the surrounding ambient air. The air monitoring data did detect some VOCs. The concentrations are low and it is not clear whether these chemicals are from the site or represent background urban levels.