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PUBLIC HEALTH ASSESSMENTMORGAN FALLS MUNICIPAL SOLID WASTE LANDFILL
ROSWELL, FULTON COUNTY, GEORGIA

EPA ID No. GAD980559413

October 28, 2004

Prepared by:

The Georgia Department of Human Resources
Under a Cooperative Agreement with
Agency for Toxic Substances and Disease Registry




Summary

In June 2001, the Georgia Environmental Protection Division (GEPD) requested that the Georgia Department of Human Resources, Division of Public Health (GDPH) address health issues associated with contaminated groundwater originating from the Morgan Falls Municipal Solid Waste Landfill (Morgan Falls landfill), a Fulton County-managed, closed landfill. At that time, GDPH reviewed available environmental sampling data to determine whether adverse health effects were possible from exposure to contaminated groundwater at this site. But given that the extent of off-site contamination originating from the landfill was then unknown, GDPH determined that once the extent of contamination was delineated, a more accurate assessment of health issues could be made. In the summer of 2003, a complete set of environmental data was released. Analyses of the results of off-site soil, groundwater, surface water, sediment, and on-site groundwater and air have confirmed that contamination originating from Morgan Falls landfill has migrated off-site to the Morgan Falls Station apartment complex directly south of the landfill, and to Morgan Falls Lake and the Chattahoochee River.

In the past nearby residents have not been, nor are they currently at increased risk for adverse health effects from exposure to contaminated groundwater - they have been using municipal water for at least 17 years. Additionally, preventative measures will ensure that exposure to contaminated groundwater will not occur in the future. Thus residents living near the Morgan Falls landfill were not in the past, nor are they currently exposed to contaminated soil, surface water, sediment, or air at levels likely to cause adverse health effects. Future exposure to contaminants at levels known to cause adverse health effects is not likely.

This public health assessment contains information about the extent of contaminated soil, groundwater, surface water, sediment, air, specific contaminants, and conclusions about the health risks posed to the public. A public health assessment is designed to provide information about the public health implications of a specific site and to identify populations for which further health actions or health studies are needed. It is not intended to serve the purpose of or to influence any other environmental investigation such as risk assessment or selection of remedial measures, or to address liability or other non-health issues.

Because of the low levels of contaminants found, residents or recreational visitors are unlikely exposed to contaminated soil, surface water, or sediment that originated from Morgan Falls landfill will experience adverse health effects. Accordingly, GDPH has categorized this site as no apparent public health hazard because
  1. exposure to contaminated soil, surface water, sediment and air do not exceed health guidelines;
  2. data are available for all environmental media to which humans are being exposed; and,
  3. community-specific health outcome data do not indicate that the site has had an adverse impact on human health.
GDPH does not have any recommendations at this time. If additional data become available, GDPH will review the information and take action, if appropriate. GDPH will also respond to all requests for information regarding health issues associated with the landfill.

Background

Site Description

The Morgan Falls Municipal Solid Waste Landfill (Morgan Falls landfill) is located in the Sandy Springs area of north Fulton County, Georgia (Figure 1). The site property is between Roswell Road and the Chattahoochee River and comprises approximately 130 acres of land (53 acres encompasses the landfill). It is bordered to the east by undeveloped land and Morgan Falls Parks and Recreation Department (Figure 2). North of the property is Morgan Falls Road, undeveloped woodlands, and Harbor Pointe Apartments. The site is bordered to the south by Morgan Falls Station, which consists of three apartment complexes, and to the west by a Georgia Power transformer station and undeveloped land.

The ground surface generally slopes moderately to steeply on all sides of the landfill, with elevations ranging from 880 to 1,010 feet above mean sea level [1, 2]. The steepest slope is on the southwestern side, and the least dramatic slope is on the northeastern corner [2].

Currently on site are an 18-hole public golf course, a golf driving range, and a recycling facility.

Site Operations and History

The Morgan Falls landfill began operations in the mid 1950s as an open dump and unpermitted landfill. Early filling consisted of dumping refuse on the bottom of the site ravines and covering that refuse with soil. Some areas were excavated to bedrock first to provide cover material. The landfill is reported to have received municipal waste, ink sludge, digested sewage waste, and unspecified liquid waste [2]. Ink sludge could contain such contaminants as dyes and solvents. The first operational plans for the site were adopted in 1971, after a significant amount of refuse was already in place. A revised set of plans was compiled in 1975, after the Georgia Environmental Protection Division (GEPD) was given authority to regulate landfills. GEPD issued a Municipal Solid Waste Permit to Morgan Falls in 1975. Operations ceased temporarily around 1980. The operating plans were revised in 1981 to expand waste fill areas. Some available information indicates that filling operations resumed, and ceased again late in 1988, but that final grading and cover placement continued for at least 2 more years [1]. The original Closure Plans, consisting of an engineered cap of compacted soil and vegetative cover, were approved by GEPD in 1994. A landfill gas collection system was installed in 1997. The GEPD issued a closure certificate on March 23, 1998, when activities were complete. Morgan Falls landfill is now in Post-Closure care.

Current post-closure care activities include groundwater monitoring, methane monitoring, and the operation of a landfill gas collection system. Monitoring wells were initially installed in 1995; five additional or replacement monitoring wells were installed in 1998 [1]. Seven additional monitoring wells were installed from 1999 to 2002, of which two monitoring wells were installed on Morgan Falls Station property to monitor flow in a fractured-rock zone. The current groundwater monitoring system consists of 20 monitoring wells and five surface water sampling points. Currently, various remediation technologies are under review before choosing the best plan of action for on/off site groundwater remediation.

Demographics, Land Use, Natural Resources Use and Hydrogeology

Demographics

The population within 1 mile of Morgan Falls is approximately 9,800 people. Using 2000 Census data, the Agency for Toxic Substances and Disease Registry (ATSDR) has calculated population information for individuals residing within a 1-mile radius of the landfill using an area-proportion special analysis technique (Figure 1).

Land Use

Morgan Falls landfill is located in an area comprised of scattered residences and commercial property. The Blue Heron Golf Club (completed in 2002) now occupies the area that was once the landfill. The closest residential properties lie adjacent to the northern and southern boundaries of the landfill, where large apartment complexes border it.

A 40-inch diameter petroleum pipeline, installed in 1979 and carrying reformulated gasoline and Georgia Power electrical lines, bisects the landfill in an east-west direction. In March 1998 the pipeline, operated by Colonial Pipeline Company (CPC), had reported petroleum releases of more than 30,000 gallons just east of the landfill [3]. In March and April 1998 CPC removed the floating gasoline with vacuum trucks and repaired the pipeline, effectively eliminating any continuing hydrocarbon source. A total of 24,752 tons of impacted soils were remediated by excavation and off-site removal [1]. The Georgia Office of Pipeline Safety issued a Compliance Order to CPC requiring CPC to remove any biodegradable landfill material under the pipeline crossing the landfill and to support the pipeline sufficiently to ensure no movement or settlement. Cleanup efforts and repair were completed by September 1998 [3].

Natural Resource Use

Municipal water has been available to all residences of Morgan Falls Station since the complex was built in 1987 [5]. Residences in the area are connected to municipal water, which comes from surface water intakes on the Chattahoochee River [2]. A review of GEPD files reveals that one private water well is located within ½ mile of Morgan Falls landfill. This well is at the Morgan Falls Dam and is owned by Georgia Power Company. The well is reported as "no longer in use" [1]. According to local officials, the intermittent streams to the southwest and east that provide site drainage are not used for recreational purposes. Nearby Morgan Falls Lake (1000 feet south of the landfill) and the Chattahoochee River (approximately ½ mile west of the landfill) are used for recreation, including fishing, boating, and rafting.

Hydrogeology

Figure 3 is a cross-section that illustrates site geology and hydrogeology. The cross section is a 3400-foot west-east cross-section of the area immediately south of the southern property line of Morgan Falls Landfill. The cross-section includes water levels, monitor well data, lithology, and bedrock contours underlying the landfill [1].

The site is located in the Piedmont physiographic region, which is characterized by both narrow and broad ridges, separated by relatively narrow valleys. At the landfill, the saprolite consists of two distinct strata. The upper strata consists of clayey sand and silt and range in thickness from 0 to 12 feet; the lower strata consists of sand and silt and ranges in thickness from 0 to 35 feet [2]. The permeability of both soils and the available water capacity is described as moderate [1]. Bedrock underlying the surface/subsurface soil is a mainly gneiss [1].

Water-bearing units that underlie the landfill and surrounding areas represent an aquifer system consisting of residual soils, saprolite, partially weathered rock, and the underlying bedrock. The uppermost aquifer on the Morgan Falls landfill site is an unconfined aquifer in the lower saprolite and the underlying jointed and fractured bedrock through joints and fractures. Using water level measurements, there appears to be an interconnection between the soil stratum and the underlying bedrock [1]. Groundwater appears to mimic surface topography and historically flows in a south to southwesterly direction from higher elevations north of the site to the discharge areas along two intermittent streams located in the southwest corner and along the eastern boundary of the site, and eventually into the Chattahoochee River. Although contaminant impacts to the groundwater are confined at or near the landfill, flow velocities in overburden groundwater have been calculated at 59 feet per year [1]. This means that contaminants would take as long as 17 years to reach Morgan Falls Lake, which is approximately 1000 feet south of the landfill.

Morgan Falls Lake and the Chattahoochee River are the two major surface water bodies in the vicinity of Morgan Falls landfill (see Figure 4). All surface water originating from the landfill is directed into detention ponds that overflow into two intermittent streams. The streams discharge into Morgan Falls Lake, which discharges into the Chattahoochee River through overflow structures [2].

Discussion



Available Data Used

Between 1990 and 2003 several investigations were conducted at Morgan Falls landfill to characterize the extent of contamination associated with releases to environmental media (e.g., soil, groundwater, air, surface water, and sediment) from the site. Available data include groundwater samples collected from monitoring wells located at Morgan Falls landfill and Morgan Falls Station. Surface soil samples were collected from 0 to 3 inches below ground surface (bgs), while subsurface soil samples were collected from greater than 2 feet bgs. All surface and subsurface soil samples were collected from Morgan Falls Station. Surface water samples were collected from 0 to 12 inches below the surface of the water, and sediment samples were collected from the sediment-surface water interface. Air samples were collected from methane monitoring points and from groundwater monitoring well headspaces, and analyzed for the presence of volatile organic compounds (VOCs).

Surface soil and sub-surface soil background samples were collected at the Empirian at Northridge apartment complex located approximately 1 mile northeast of Morgan Falls landfill. Chattahoochee River sediment and surface water background samples were collected at the Roswell River Landing, approximately 2 miles upstream of Morgan Falls landfill. Sediment and surface water background samples for Morgan Falls Lake were taken at the Empirian at Northridge apartment complex.

Pathway Analysis

GDPH identifies pathways of human exposure by identifying environmental and human components that might lead to contact with contaminants in environmental media. A pathways analysis considers five principal 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. a receptor population.
Completed exposure pathways are those in which all five elements are evident, and indicate that exposure to a contaminant has occurred in the past, is presently occurring, or will occur in the future. GDPH regards persons who come into contact with contamination as exposed. For example, persons who reside in an area with contaminants in air, or who drink water known to be contaminated, or who work or play in contaminated soil, are considered to be exposed to contamination. Potential exposure pathways are those for which exposure seems possible, but one or more of the elements is not clearly defined. Potential pathways indicate that exposure to a contaminant could have occurred in the past, could be occurring now, or could occur in the future. However, key information regarding a potential pathway may not be available. It should be noted that the identification of an exposure pathway does not imply that health effects will occur. Exposures may, or may not be substantive. Thus, even if exposure has occurred, human health effects may not necessarily result [4].

GDPH reviewed the site's history, community concerns, and available environmental sampling data. After this review GDPH identified exposure pathways that warranted consideration. Each of the completed and potential exposure pathways identified for the Morgan Falls site are discussed in the following sections. The completed exposure pathways identified at the Morgan Falls site are summarized in Table 1, and the potential exposure pathways identified are found in Appendix B.

Evaluation Process

For each environmental medium (e.g., air, soil, groundwater), GDPH examines the types and concentrations of contaminants of concern (COCs). In preparing this health assessment GDPH used the Agency for Toxic Substances and Disease Registry (ATSDR) comparison values, and other agencies' reference values, to screen contaminants that could warrant further evaluation. Comparison values (CVs) are concentrations of contaminants that can reasonably (and conservatively) be regarded as harmless, assuming default conditions of exposure. The CVs generally include ample safety factors to ensure protection of sensitive populations. Because CVs do not represent thresholds of toxicity, exposure to contaminant concentrations above CVs will not necessarily lead to adverse health effects. CVs and the evaluation process used in this document are described in more detail in Appendix C. GDPH then considers how persons could come into contact with the contaminants. Because the level of exposure depends on the route and frequency of exposure and the concentration of the contaminants, this exposure information is essential to determine whether a public health hazard exists.

The contaminants identified for each exposure pathway related to the Morgan Falls site are discussed in the following sections and presented in Tables 2 and 3. Other contaminants not exceeding CVs were reviewed, but not selected for additional evaluation in this assessment. The tables also include the chemical-specific CVs that GDPH considered in the selection process.

When a contaminant exceeds a CV, the toxicological evaluation presented requires a comparison of calculated site-specific exposure doses (e.g., amount of the contaminant believed to enter the body at the person's body weight for an estimated duration of time) with an appropriate health guideline. The health guidelines are health-protective values incorporating various uncertainty factors to account for varying human susceptibility and the use of animal data to evaluate human exposure. Health guidelines used include ATSDR's Minimal Risk Levels (MRLs) and the U.S. Environmental Protection Agency's (EPA's) Reference Dose (RfDs). MRLs and RfD are described in more detail in Appendix C. Usually little or no information is available for a site to know exactly how much exposure is actually occurring, so health assessors assume worse case scenarios where someone received a maximum dose. Actual exposure is likely much less than the assumed exposure. In the event that the calculated, site-specific exposure dose for a chemical is greater than the established health guideline, it is then compared to exposure doses from individual studies documented in the scientific literature that have reported health effects. If a COC has been determined to be cancer causing (carcinogenic), a cancer risk is also estimated.

Completed Exposure Pathways

Ingestion is defined as direct ingestion or actively and passively eating soil particles; and, indirect ingestion, or inhalation of dust particles that are then expelled from the respiratory tract and swallowed (ingested). However, it is important to note that the other routes of exposure - inhalation of very small particles and vapors into the lungs, and direct skin contact (dermal absorption) - could contribute additional exposure to contaminants at this site. But these exposure routes are considered to be minimal and not of health concern.

Table 1: Completed Exposure Pathways
Pathway Exposure Pathway Elements Time
Sources Medium Point of Exposure Route of Exposure Exposed Population
Soil Movement of contaminants discharged onto landfill along with high background levels of some metals Surface Soil Surface Soil, Dust at Morgan Falls Station Ingestion, Inhalation, Dermal Absorption Residents, Workers, Trespassers, Visitors Past
Present
Future
Surface water Movement of contaminants from landfill surface water run-off or from groundwater to surface water Surface
Water
Morgan Falls Lake, Chattahoochee River, and associated drainage ditches Ingestion, Dermal Absorption Residents, Recreational Visitors, Fishers Past
Present
Future
Sediment Movement of contaminants from surface of landfill to groundwater and surface water Sediment Morgan Falls Lake, Chattahoochee River Ingestion, Dermal Absorption Residents, Recreational Visitors, Fishers Past
Present
Future


Soil

Soil samples were collected in 2003 to determine the extent of soil contamination likely to have originated from Morgan Falls landfill. Soil samples were collected from 14 locations (2 were subsurface samples) throughout the Morgan Falls Station property, and 2 surface/subsurface soil background samples were collected from the Empirian at Northridge apartment complex. Aluminum, arsenic, vanadium, and benzo(a)pyrene were detected at concentrations above CVs at Morgan Falls Station. The maximum concentrations were 22,000 parts per million (ppm) for aluminum, 8.7 ppm for arsenic, 790 ppm for vanadium, and 0.230 ppm for benzo(a)pyrene [1]. To conceptualize a part per million, one can think of it as 1 inch in 16 miles. It should be noted that background concentrations of aluminum, arsenic, and benzo(a)pyrene were similar to concentrations detected at Morgan Falls Station. Subsurface soil background concentrations of aluminum and surface soil concentrations of benzo(a)pyrene were actually higher in the background samples than the concentrations detected at Morgan Falls Station. Table 2 presents the ranges of contaminants found at Morgan Falls Station as well as established CVs.

The sampling event conducted in 2003 did not include soil samples on site at the former landfill. The only known soil sampling event that has ever taken place on the Morgan Falls landfill occurred in 1990. Results indicated the presence of several volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs), as well as inorganic metals including arsenic, copper, lead and manganese. It must be noted, however, that with the exception of arsenic, aluminum, vanadium, and benzo(a)pyrene were not previously detected in soil from the landfill.

A final cap was constructed in 1997 to minimize infiltration and erosion from the landfill [1]. The cap is composed of 24 and 36 inches of earthen material laid on the side slopes and top of the landfill, respectively. Moreover, in 2002 a professionally landscaped and contoured golf course was completed over the landfill. This could further minimize infiltration and erosion.

Table 2: Summary of soil sampling results for Morgan Falls Station apartment complex. Sampling data collected in 2003 [2].
Contaminant Number of samples Number of Detections Range of Concentrations Greater than the CV*ppm Health-Based Comparison Value (CV) ppmType of CV
Aluminum 13 13 9,800 to 22,000 4000 EMEG-pci
Arsenic 13 13 1.2 to 8.7 0.5 CREG
Vanadium 13 13 32 to 790 6 EMEG-pci
Benzo(a)pyrene 13 4 0.190 to 0.230 0.0001 CREG
For contaminants with multiple comparison values, the lowest comparison value was selected for this presentation.
Abbreviations used: EMEG-pci: Environmental Media Evaluation Guide for Children with pica intermediate exposure.
CREG: Cancer Risk Evaluation Guide.
*ATSDR, Soil comparison values (Summer 2004)
Background results: aluminum (12,000 ppm surface soil, 34,000 ppm subsurface soil), and surface soil concentrations of arsenic (5.1 ppm), Vanadium (59 ppm), and Benzo(a)pyrene (0.350 ppm)
Using soil sample results taken from Morgan Falls Station in 2003, exposures were evaluated to determine the likelihood of health effects. Adult, child, and children with pica exposure doses were calculated for the concentration of contaminants based on the maximum detected concentration in soil on Morgan Falls Station. It must be noted that apartment residents are a transient population not likely to live in the same apartment complex for many years.


For adults and children, an exposure duration of 5 years, assuming 2 hours per day exposure, was used in the calculations (see Appendix C). Oral ingestion of soil is the route of most concern at Morgan Falls Station. Inhalation of contaminated dust found at Morgan Falls Station is possible; however, the dose of a soil contaminant that results from oral ingestion is likely to exceed the dose resulting from dust inhalation (A Kemp, Assistant Property Manager of Morgan Falls Station, personal communication, March 17, 2004).

Groundcover, mulch, asphalt and sidewalks on the fully landscaped complex further minimize the likelihood of dust emissions. Direct contact with contaminated soil increases the potential for dermal (skin) absorption; however, chemical-specific factors such as lipophilicity, polarity, volatility, molecular weight, and water solubility also affect dermal absorption [7]. Dermal and inhalation exposure doses were calculated and levels were insignificant for all COCs (Appendix C). Estimated doses relative to health guidelines are presented in Table 3.

Table 3: Calculated doses from exposure to contaminated soil compared to health guidelines
Contaminant Total Estimated Dose* mg/kg/day Health Guideline mg/kg/day Numeric Cancer Risk**
Aluminum Adult: 0.003
Child: 0.01
Pica: 0.55
MRL: 2 not applicable
Arsenic Adult: 0.000001
Child: 0.0000075
Pica: 0.0002
MRL: 0.0003 1.6 x 10-6
2.4 x 10-6
Vanadium Adult: 0.0001
Child: 0.0005
Pica: 0.02
MRL: 0.003 not applicable
Benzo(a)pyrene Adult: 9 x 10-9
Child: 5 x 10-8
Pica: 2 x 10-6
not established 6.7 x 10-8
7.8 x 10-8
* Based on ingestion and dermal exposure calculations
mg/kg/day: milligrams per kilogram per day
MRL: minimal risk level (ATSDR Health Guidelines, Summer 04)
* Based on EPA's cancer slope factors [Arsenic: 1.5 (mg/kg/day)-1, Benzo(a)pyrene: 7.3 (mg/kg/day)-1]


Aluminum

The calculated exposure doses for aluminum applicable to adults, children, and children with pica are below the established health guideline of 2.0 mg/kg/day. Adult exposures are approximately 600 times below the MRL, exposure to children is approximately 200 times below the MRL, and exposure to a pica child would be approximately 4 times below the MRL. The level of aluminum associated with neurological effects in a study from which the MRL was derived is more than 51,000 times higher than the calculated exposure dose for adults, and nearly 300 times greater than the calculated exposure for a children with pica for contaminated soil from Morgan Falls Station [8]. Because the difference between calculated exposure doses and exposure doses that are known to be associated with health effects is so great, GDPH concludes that adverse health effects from exposure to soil aluminum are not expected to result from current and future exposures to soil at Morgan Falls Station. Concentrations of soil aluminum that may have existed in the past are unknown. Nevertheless, adverse health effects from past exposure to aluminum are not expected - current estimated exposure doses are substantially below levels in which adverse health effects would likely occur.

The National Toxicology Program (NTP) has not classified aluminum as a known carcinogen. Carcinogenic effects from ingestion of aluminum are not expected.

Arsenic

The calculated exposure doses to arsenic for adults, children and children with pica are far below the established health guideline of 0.0003 mg/kg/day. The health guideline used is ATSDR's chronic oral MRL, which is based on a study conducted in Taiwan where a large number of poor farmers were exposed to high levels of naturally occurring arsenic in well water. A control group used in the study showed no health effects at 0.0008 mg/kg/day [9]. Because the difference between calculated exposure doses and the exposure dose deemed to be health-protective is so great, GDPH concludes that non-carcinogenic adverse health effects from arsenic exposure at Morgan Falls Station are not expected to result from current and future exposures. Concentrations of soil arsenic that could have existed in the past are unknown. Still, adverse health effects from past exposure to arsenic are not expected, again because current estimated exposure doses are substantially below levels in which adverse health effects would likely occur.

Data used to develop the health guideline and assess carcinogenic effects of arsenic exposure are based on the ingestion of drinking water, not on the ingestion of soil or food containing arsenic. The EPA classifies inorganic arsenic as a human carcinogen, using sufficient evidence from human data. Increased mortality from multiple internal organ cancers (i.e., liver, kidney, lung, and bladder) and an increased incidence of skin cancer were observed in populations consuming drinking water high in inorganic arsenic [10].

A significant dose-response relationship was found between arsenic levels in artesian well water in 42 villages in southwestern Taiwan [11]. Residents in these villages have used and consumed water high in arsenic from deep artesian wells for more than 70 years. Arsenic levels in drinking water ranged from 0.010 to 1.752 ppm (mg/l). The study population had 898,806 person-years of observation and 202 liver cancer, 304 lung cancer, 202 bladder cancer, and 64 kidney cancer deaths. Mortality rates increased significantly with age for all cancers and significant dose- response relationships were observed between arsenic level and mortality from cancer of the liver, lung, bladder and kidney in most age groups of both males and females [12]. The data generated provide evidence for an association of the levels of arsenic in drinking water and duration of exposure with the rate of mortality from cancers of the liver, lung, bladder, and kidney cancer [13]. That said, however, that arsenic levels found at Morgan Falls Station are contained in the soil, and that arsenic ingested from [default] concentrations in soil would be much less than if similar concentrations in drinking water were consumed on a daily basis. Furthermore, the development of cancer can be related to other factors, including one's lifestyle: cigarette smoking, heavy drinking, and diet (e.g., excess calories, high fat, and low fiber). Other important cancer risk factors generally include reproductive patterns, sexual behavior, and sunlight exposure. A family history of cancer can also increase a person's chances of developing cancer. Numeric risks of contracting cancer estimated for individuals exposed to arsenic concentrations in the soil at Morgan Falls Station, based on estimated doses, are 1.6 x 10-6 (1.6 in 1 million) for adults, and 2.4 x 10-6 (2.4 in 1 million) for children. Adult numeric risks are based on a lifetime of exposure (70 years), and children's numeric risks are based on 15 years of childhood. The numeric risks are low for both children and adults. Furthermore, because of the transitory nature of apartment living, prolonged exposure to site contaminants is unlikely, so the risk of contracting cancer from site related contaminants is, in all probability, further reduced.

Vanadium

The calculated exposure doses for adults are approximately 30 times lower than the established health guideline, 6 times lower for children, and 7 times higher than the established health guideline for children with pica of 0.003 mg/kg/day. The health guideline is ATSDR's intermediate oral MRL, which was derived from a study of rats exposed to various concentrations of vanadium pentoxide in their drinking water for 3 months. The calculated dose administered to the rats was 0.3 mg/kg/day [14]. No observed adverse health effects were seen at this level [No Observed Adverse Effect Level (NOAEL)] - this dose was used to establish the intermediate MRL for vanadium, and only an uncertainty factor of 100 was used, effectively reducing the dose used for the intermediate MRL to 0.003 mg/kg/day [14]. Adverse developmental effects, cardiovascular effects, and gastrointestinal effects at levels greater than the NOAEL have been reported [15]. Therefore, the concentration of vanadium associated with NOAEL in the study by which the MRL was derived is 3,000 times higher than the calculated exposure dose for adults, 600 times greater than the calculated exposure for children, and approximately 15 times higher than the calculated exposure for a children with pica from soil at Morgan Falls Station. Again, it must be noted that vanadium levels found at Morgan Falls Station are contained in the soil, and that vanadium ingested from [default] concentrations in soil would be much less than if similar concentrations in drinking water were consumed on a daily basis. Because the difference between the calculated exposure doses and exposure doses that are known to be associated with health effects, GDPH concludes that non-carcinogenic adverse health effects from exposure to soil vanadium are not expected to result from current and future exposure to soil at Morgan Falls Station. Although concentrations of soil vanadium that might have existed in the past are unknown, adverse health effects from past exposure to vanadium are not likely because the likely site-specific exposure doses would be low.

The NTP has not classified vanadium as a known carcinogen. Carcinogenic effects from ingestion of vanadium are not expected.

Benzo(a)pyrene

An evaluation of the available benzo(a)pyrene soil data indicate that the calculated exposure dose is 9.2 x 10-9 (9.2 billionths) mg/kg/day for adults, 5.0 x 10-8 (500 millionths) mg/kg/day for children, and if a child exhibited pica characteristics, the estimated dose is 2.0 x 10-6 (2 millionths) mg/kg/day. A health guideline has not been established for benzo(a)pyrene, however, a NOAEL of approximately 200 mg/kg/day has been established for mice undergoing intermediate exposure to benzo(a)pyrene, when reproductive effects were looked at [16]. Non-carcinogenic adverse health effects from soil ingestion are not expected to result from current and future exposure to soil at Morgan Falls Station. Although concentrations of soil benzo(a)pyrene that may have existed in the past are unknown, adverse health effects from past exposure to benzo(a)pyrene are not likely because the likely site-specific exposure doses would be low.

The International Agency for Research on Cancer classifies benzo(a)pyrene as probably carcinogenic to humans (limited human evidence, sufficient evidence in animals). The EPA also classifies benzo(a)pyrene as a probable human carcinogen, while the NTP suggests that benzo(a)pyrene is reasonably anticipated to be a carcinogen. Human data specifically linking benzo(a)pyrene to a carcinogenic effect are lacking. Still, multiple animal studies in many species demonstrate benzo(a)pyrene to be carcinogenic following administration by numerous routes.

One study conducted in 1981, where rats were fed 0.15 mg/kg benzo(a)pyrene (reported to be "highly pure" in their diet either every 9th day or 5 times/week, showed a statistically significant tendency for the proportion of animals with tumors of the forestomach, esophagus or larynx to increase steadily with dose [17]. As part of the same study, rats were administered Benzo(a)pyrene by gavage. A statistically significant association between the dose and the proportions of rats with tumors of the forestomach, esophagus, or larynx was observed. However, this association is not characterized by a linear trend; the linearity was affected by the apparently reduced tumor incidence seen in the high-dose group [18].

Intratracheal instillation and inhalation studies in guinea pigs, hamsters, and rats have resulted in elevated incidences of respiratory tract and upper digestive tract tumors [19]. Trend analysis for incidences of both respiratory tract tumors and upper gastrointestinal tract tumors showed a statistically significant tendency for the proportion of animals with either tumor type to increase steadily with increased dose [18].

Numeric risks for contracting cancer estimated for individuals exposed to benzo(a)pyrene concentrations in the soil at Morgan Falls Station, based on estimated doses, are 6.7 x 10-8 (6.7 in 100 million) for adults, and 7.8 x 10-8 (7.8 in 100 million) for children. Adult numeric risks are based on a lifetime of exposure (70 years) and children's numeric risks are based on 15 years of childhood. The numeric risks are insignificant for both children and adults. Furthermore, because of the transitory nature of apartment living, prolonged exposure to site contaminants is unlikely, so the risk of contracting cancer from site-related contaminants is likely to be further reduced.

Surface Water and Sediment

Surface water runoff from Morgan Falls landfill discharges into Morgan Falls Lake and eventually into the Chattahoochee River. The landfill is about 2 miles upriver from the Cobb-Marietta Water Authority and about 11 miles upriver of the City of Atlanta surface water intakes for potable water. These two intakes combined serve more than 2 million people [2]. Along this section of the river the Chattahoochee is also a fishery and recreation area. Morgan Falls Lake is man-made and is not used for fishing, nor is swimming allowed in the lake [5].

In 2002 surface water and sediment samples were collected from Morgan Falls Lake and the Chattahoochee River to determine the extent of surface water/sediment contamination likely to have originated from Morgan Falls landfill. Prior to 2002, surface water and sediment samples had not been collected at Morgan Falls Station, or the Chattahoochee River. The sampling event conducted in 2002 did not include surface water or sediment from the former landfill, where a golf course is now located.

Surface water samples above a drinking water CV included one sample from the Chattahoochee River downstream of Morgan Falls landfill, a Chattahoochee River background sample, and five samples (including background) from Morgan Falls Lake, located on Morgan Falls Station property. Manganese was detected in the surface water of both the Chattahoochee River and Morgan Falls Lake. The manganese concentration was 3,200 parts per billion (ppb) in the Chattahoochee River; the maximum manganese concentration detected in Morgan Falls Lake was 13,000 ppb. Again, however, it must be noted, that swimming is not allowed at Morgan Falls Lake, and the possibility of exposure would rest on individuals not heeding the posted signage. The manganese concentrations detected in background samples were 59 ppb and 27 ppb in the Chattahoochee River and Morgan Falls Lake, respectively. To conceptualize a part per million, one can think of it as 1 inch in 16,000 miles. Table 4 summarizes surface water and sediment sampling results [1].

Table 4: Surface Water Sampling Data for Morgan Falls Station Apartment Complex and the Chattahoochee River. Sampling data collected in 2003 [2].
Contaminant Number of Samples Number of Detections Range of Concentrations
Measured at Levels
Greater than the CV (ppb)
Health-Based Comparison Value (CV) (ppm) Type of CV
ManganeseChattahoochee 7 1 3200 ppb 500 RMEGc
ManganeseMorgan Falls Lake 6 4 620 to 13,000 ppb 500 RMEGc
For contaminants with multiple comparison values, the lowest comparison value was selected for this presentation.
Abbreviations used:
RMEGc: Reference dose Media Evaluation Guide for a child.
*ATSDR, Drinking Water comparison values (Spring 2004)
CV: comparison values
ppb: parts per billion
ppm: parts per million
Background results: Manganese (59 ppb surface water in the Chattahoochee River, 27 ppb for Morgan Fall Lake)


Sediment samples above a soil CV were taken from seven locations on the Chattahoochee River downstream of Morgan Falls landfill. A background sediment sample was also obtained. Vanadium was detected in all the sediment samples obtained from the Chattahoochee River, including the background sample. Results ranged from 9.8 to 53 ppm, while the background sample was 35 ppm [1].

Analyzing surface water samples collected from the Chattahoochee River and Morgan Falls Lake in 2003, exposures were evaluated to determine the likelihood of health effects. Adult and child exposure doses were calculated based on the maximum detected concentration of contaminants in surface water and sediment in the Chattahoochee River and surface water in Morgan Falls Lake. For adults and children, a conservative exposure duration of 1 hour per day exposure was incorporated into the calculations (see Appendix B). Dermal absorption is the route of most concern with surface water and sediment contaminants. Ingestion of surface water and sediment is possible, but the likelihood of swallowing sediment or drinking river or lake water in volumes large enough to be of concern is not very likely. Estimated doses relative to health guidelines are presented in Table 5.

Table 5: Estimated Doses Obtained from Soil Compared to Health Guidelines.
Contaminant Estimated Doses from Absorption (mg/kg/day) Dermal Health Guideline mg/kg/day
Manganese
(Chattahoochee River)
Adult: 0.0009
Child: 0.002
RfD: 0.14
Manganese
(Morgan Falls Lake)
Adult: 0.004
Child: 0.008
RfD: 0.14
Vanadium
(Morgan Falls Lake)
Adult: 0.0002
Child: 0.00025
MRL: 0.003
mg/kg/day: milligrams per kilogram per day
RfD: EPA reference dose. hwww.epa.gov/iris
MRL: minimal risk level (ATSDR Health Guidelines, Spring 2004)


Manganese

Adverse health effects are not likely to be associated with adult and childhood exposure via direct contact with manganese present in the Chattahoochee River or in Morgan Falls Lake surface water. For inorganic manganese compounds, dermal (skin) exposure is not a typical pathway for exposure - manganese does not readily penetrate the skin [17]. The permeability of the skin to a chemical is influenced by the physicochemical properties of the substance, including its molecular weight (size and shape), electrostatic charge, hydrophobicity, and solubility in water or lipid media. The estimated doses were based on a metal default permeability coefficient of manganese to skin [21]. Because the difference between calculated exposure doses and the exposure dose deemed to be a health-protective value is substantial, GDPH concludes that non-carcinogenic adverse health effects from manganese exposure from the Chattahoochee River and Morgan Falls Lake are not expected to result from current and future exposure. Although concentrations of surface water manganese that might have existed in the past are unknown, adverse health effects from past exposure to manganese are not likely because the likely site-specific exposure doses would be low.

Vanadium

Adverse health effects are not likely to be associated with adult and childhood exposure via direct contact with vanadium present in the Chattahoochee River sediment. No studies were located regarding absorption in humans or animals after dermal exposure to vanadium, although absorption by this route is generally considered very low. Because vanadium is a metal, absorption through the skin is thought to be quite minimal due to its low solubility in water [14]. Dermal absorption calculations assume that individuals exposed to sediment are barefoot, which is unrealistic given the nature of river bottoms. Furthermore, the MRL is based on the ingestion of soil; the ingestion of similar default values of sediment is unlikely, because sediment is underlying surface water and upon departure from the water body is likely to be washed off by flowing water. Nonetheless, the difference between calculated exposure doses and the exposure dose deemed to be a health-protective value is substantial.


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