PETITIONED PUBLIC HEALTH ASSESSMENT
ATLANTA GAS LIGHT COMPANY
AUGUSTA, RICHMOND COUNTY, GEORGIA
The Atlanta Gas Light facility (AGL) is located in Augusta, Georgia. The AGL site consists of three parcels (Northern, Southern, and Western) separated by 8th and Taylor Streets and the Third Level Canal. The site is a former manufactured-gas plant that operated from approximately 1852 through 1954. AGL derived gas by heating coal, which produced tar by-product. This tar was pumped to an adjacent facility, Southeastern Bituminous, until the early 1950s when Southeastern Bituminous shut down. After that time, AGL reportedly buried some of its tar in a trench on the southern parcel. Other process-related activities have resulted in the contamination of soil and groundwater as evidenced in various site investigations, beginning with the preliminary assessment in 1992. In April 1994, a contractor for AGL initiated a comprehensive Remedial Investigation of the site that revealed contamination of surface water, soil, sediment, and groundwater both on- and off-site. Contaminants detected include metals, polycyclic aromatic hydrocarbons (PAHs), and volatile organic compounds (VOCs).
Area residents have expressed several concerns relating to exposure to tar products and contaminated air, surface water, soil, and groundwater. Some residents have reported experiencing adverse health reactions after contacting the soil on their property and wonder whether their soil is contaminated. Several residents expressed concern that the number of cancer deaths in their neighborhood may be unusually high compared with other neighborhoods. On September 4, 1996, area residents living adjacent to the AGL site requested that the Agency for Toxic Substances and Disease Registry (ATSDR) investigate the existence of hazardous contaminants at the AGL site and determine whether potential exposures to site-related waste products are at levels of public health concern.
ATSDR reviewed available data and evaluated who might be exposed to site-related contaminants and to what extent. Available data of the current level of contaminants detected on-and off-site indicate the AGL site represents No Apparent Public Health Hazard for current and future exposures. However, although information is not available, exposure to contaminants in the past is plausible, and the site represents an Indeterminant Public Health Hazard for past exposures.
The site is fenced, thereby limiting exposure to contaminated soil, sediment, and surface water. Although some evidence of trespassing was observed on the site, it is doubtful that trespassers would experience adverse health effects from these potentially intermittent and short-term exposures. The extent of past human exposure to contaminated media, including tar-like material observed on site, is uncertain. Limited exposure is not expected to be associated with adverse health effects.
People living in the vicinity of the site are not known to be exposed to site-related contaminants at levels associated with health hazards, although available soil data are limited. Although no off-site "product" has been identified or sampled by investigators, residents report black tar "oozing" onto their properties. Some off-site wells have low levels of constituents of tar (e.g., VOCs and PAHs), suggesting some off-site groundwater contaminant migration. Area residents receive drinking water from the municipal water supply system and, therefore, do not consume the contaminated groundwater. Area residents may be exposed to contaminated groundwater during high water events, such as heavy rain storms; however, these limited exposures are not likely to present a public health hazard.
Exposure to measured air concentrations of benzene during the 5-month decommissioning of a gas holder on-site is not likely to pose a health hazard. The extent of longer-term exposure, if any, is not known because no other air data are available.
Using the results of this health assessment, ATSDR makes the following recommendations to protect the health of area residents:
- Inform residents of the potential health effects associated with contacting contaminated groundwater, soil, sediment, and air in the past, present, and future. Provide educational support upon request.
- Perform additional off-site surface-soil sampling to more fully characterize contamination in residential yards, testing specifically for lead, PAHs, and tar-related materials.
- Restrict access to the Third Level Canal and the former Southeastern Bituminous Property by fencing the area.
- Prohibit the use of area groundwater for household, industrial, or irrigation purposes.
- Present the results of the public health assessment to the community and discuss any remaining community health concerns. Because some area residents may be leaving the neighborhood soon, ATSDR's findings should be widely distributed.
The Atlanta Gas Light (AGL) site is a former manufactured-gas plant (MGP) in Augusta, Richmond County, Georgia, which operated from 1852 through 1954. The site covers approximately 3.5 acres and consists of three parcels (Northern, Southern, and Western). See Appendix A for site location maps and site plans for the three parcels and the adjacent Third Level Canal. For the purposes of this public health assessment, the word "site" refers to all three parcels and the Third Level Canal. According to site representatives, the property has been fenced throughout its years of operation. A chainlink fence was extended around portions of the canal in 1992.
Over AGL's 102-year operation, three different gas manufacturing processes were used, with varying amounts of coal and oil feedstocks. By-products included tar, spent oxide, coal dust, and cinders. Southeastern Bituminous, an asphalt plant on Barnes Street, purchased tar from AGL as well as other manufactured gas sites. The Southeastern Bituminous plant was closed in the 1950s when natural gas was brought to Augusta. Following Southeastern Bituminous's closing, AGL reportedly buried small quantities of tar in a trench on the southern parcel. AGL ceased manufacturing gas in the 1950s, but the site was used as an operations center (for storing vehicles and refueling) until the mid 1980s, with offices located in the main building on the Northern Parcel.
As a result of AGL's gas-manufacturing activities, on-site surface and subsurface soil, groundwater, sediment and surface water became contaminated with waste products. Various site investigations were performed including a remedial investigation (RI), under a consent order entered into by AGL and the Georgia Environmental Protection Division (GA EPD) of the Georgia Department of Natural Resources. The RI and previous site investigations indicated the presence of groundwater contaminants at concentrations that exceeded federal and state Maximum Contaminant Levels (MCL) for drinking water and soil/sediment contamination. Appendix B presents a chronology of site-related events, including the various site investigations.
Area residents filed a lawsuit against AGL to recover damages suffered through their close proximity to the site. The lawsuit is currently being settled, and AGL estimates that approximately 60 residents will vacate their properties in the King, Taylor, and 7th Street area. AGL plans to tear down the homes and leave the lots vacant. The company estimates that 70% of residents who filed suit will vacate their homes, although the exact total is not known. AGL's primary goal is to remove vacated houses immediately to prevent them from attracting vagrants.
The following sections present background information on the three on-site parcels and the Third Level Canal.
The Northern Parcel contained the manufacturing operations and gas storage. The parcel is bounded by Walton Way, 8th Street, and the Third Level Canal and is sparsely vegetated. ATSDR observed some evidence of trespassing (e.g., cigarette butts, beer bottles) in these areas during its site visit. ATSDR also observed tar-like material in the central portion of the parcel and along the border of the Third Level Canal. On-site buildings and facilities (identified on maps printed between 1904 and 1954) once included four gas holders, oil tanks, gas purifiers, a tar separator, a retort house, and a main building. The only structures remaining on this parcel include the first floor of the main building and old concrete pads. Several aboveground, gas-transmission pipes are located near the southern corner of this parcel (Law Engineering and Environmental Services, Inc., 1996).
The Southern Parcel, bounded by Taylor and King Streets and the Third Level Canal, contained the foundation of a former building and Gas Holder No. 5, a large aboveground storage tank. Two properties on King Street (one of which appears to be abandoned) are within approximately 15 feet of where the tank was formerly located. Directly south of where the holder was located is an open grassy area. As mentioned above, small quantities of tar were buried in a trench on this parcel after Southeastern Bituminous closed. During AGL's site investigations, tar-like material was observed in several locations on this parcel (Law Engineering and Environmental Services, Inc., 1996). This tar-like material was sampled during the RI.
Gas Holder No. 5 was a 1.5-million-cubic-foot gas holder that contained liquids consisting of two layers: an approximately 4-foot-thick layer of by-product-like material, and an approximately 27-foot-thick water layer. The 3 million gallons of water in the holder were pumped through a carbon filter in an on-site treatment system, tested weekly, and sent out through the municipal sewer. AGL completed pumping this wastewater in March 1997. The gas holder was dismantled on May 19, 1997. Dismantling the holder took approximately 3 weeks.
The Western Parcel is on D'Antignac Street, bordered by the Third Level Canal and residential housing. A city park is located immediately southwest (across the street). The parcel contains the remains of a small concrete foundation. The Western Parcel was reportedly used primarily for storage of gravel and street rubble. Earlier maps of the site indicate that an aboveground storage tank was formerly located on this parcel. Habitat For Humanity has expressed interest in the Western Parcel, and AGL may donate the property to this group (Remediation Technologies, Inc., 1997a).
AGL released a Remedial Investigation/Feasibility Study (RI/FS) report for the Western Parcel in February, 1997. AGL has separated the Western Parcel data from the rest of the RI sampling data because remedial activities at this parcel are scheduled to occur before remedial activities at other site areas. AGL reports in the RI that sampling data collected during the RI, Preliminary Assessment, and Site Investigation show the Western Parcel to have low levels of contamination. RI sampling data identified one area of tar-like material in surface soil. Because the Western Parcel is less contaminated than the Northern and Southern parcels, remediation of the Western Parcel is expected to be limited compared with that required for the rest of the site (Remediation Technologies, Inc., 1997a).
Third Level Canal
The Third Level Canal was built in 1848 to serve as a water source and storm-water-runoff conduit. The canal is part of a network of canals, owned and operated by the city of Augusta. The section of the canal under study by AGL is approximately 5,000 feet long and extends between 5th and 12th Streets. AGL completed an RI for the Third Level Canal on January 31, 1997. A map of the canal appears in Appendix A. Currently, the canal is filled with approximately 3 feet of refuse, weeds, and mud. No significant water flow occurs in the canal except during heavy rains; it has not been used as a waterway for approximately 100 years. Large quantities of tar are visible along the embankment of the canal, and ATSDR observed a strong tar-like odor during its scoping visit to the site in January 1997.
Under normal conditions, the portion of the canal west of 8th Street flows northwest and the portion east of 8th Street flows southeast. Historically, during flood conditions, flood gates were closed at 12th Street, the current was reversed between 12th and 8th Streets, and water flowed southeast toward Beaver Dam Ditch. From there, the water flowed to the Phinizy Swamp and then out to the Savannah River (Remediation Technologies, Inc., 1997b).
The Augusta Canal Authority wants to restore the canals and develop a historic site, as was done with the Erie Canal.
During the RI, AGL collected off-site soil and groundwater samples from areas surrounding the AGL property. For sampling purposes, AGL divided the off-site areas into the eight blocks (see map, Appendix A) described below:
- Block A is north of the Northern Parcel and includes an Amoco Gasoline Station and a self-service car wash; AGL sampled surface and subsurface soil (deeper than 2 feet), and groundwater.
- Block B is adjacent to the Northern Parcel, west of the canal. The Southeastern Bituminous Company was formerly located on this property. Access was not granted for sampling the former Southeastern Bituminous site; however, AGL observed a tar-like substance covering portions of the ground surface and the banks of the canal (Law Engineering and Environmental Services, Inc., 1996). One geoprobe field-screening location, a monitoring well, and piezometer were sampled at Block B, but not on Southeastern Bituminous' former property.
- Block C includes the Western Parcel. Sampling results are presented in the Western Parcel RI and are summarized in this report in Appendix D, Tables 2, 8, and 10.
- Block D is located northeast of the Northern Parcel. AGL sampled shallow and deep groundwater within this area.
- Block E is located east of the Northern Parcel and north of the Southern Parcel. The Trinity Christian Methodist Episcopal (CME) Church occupies the southern third of the area. AGL sampled surface soil, subsurface soil, shallow groundwater, and deep groundwater.
- Block F is not described in the RI and no samples were taken from the area.
- Block G is located northeast of the Southern Parcel and contains closely spaced residential properties. AGL sampled deep groundwater in this area.
- Block H is located east of the Southern Parcel and is bounded on the south by the Third Level Canal. AGL collected surface soil, subsurface soil, shallow groundwater, and deep groundwater samples here.
ATSDR completed a Petitioned Scoping Report on May 12, 1997, and subsequently held a Petitioned Screening Committee (PSC) meeting to evaluate the report. The PSC determined that available data indicating the presence of soil and water contamination constituted a reasonable basis for conducting additional public health activities in response to the community's concerns about the AGL site. ATSDR responded to the petitioners in a July 1997 letter reporting the PSC's findings.
ATSDR staff met with community members in January 1997. Approximately 31 residents attended an informal community meeting at the CME Church, where discussions centered around community health concerns and questions about possible exposure to site contaminants. Community members requested that ATSDR evaluate the extent of their exposure. In addition, ATSDR staff met with the Georgia Department of Public Health and the Augusta County Health Department.
During January 1997, ATSDR staff conducted a site visit of the three AGL parcels and the Third Level Canal. ATSDR examined the Gas Holder No. 5 tank on the Southern Parcel while AGL was in the process of removing it. ATSDR spoke with AGL's on-site contractors about a trespassing and vandalism incident that had occurred in December 1996. AGL subsequently hired a night security guard, and no other acts of vandalism or trespassing have been reported. The area formerly occupied by Southeastern Bituminous was visible from the Northern Parcel. The site appeared abandoned and was not fenced. AGL informed ATSDR that it took possession of the Southeastern Bituminous property in May 1997 and will be including it in the cleanup activities.
ATSDR held a community availability session at the CME Church in January 1997. The original petitioner requested that all responsibilities associated with the petition process be turned over to the church's minister and parishioners. The church is located on Taylor Street, across the street from the site's Southern and Northern Parcels. Meeting participants, some of whom reported using the church for their children's day care, expressed concern about possible health effects associated with exposure to site contamination.
To evaluate potential health effects associated with exposure to hazardous substances in the environment, ATSDR obtains information on the population in the vicinity of the site ("demographics"), types of land use near the site, and natural resource use in the area.
Population information is needed because some types of illnesses and diseases are more common in certain age groups such as the elderly or children, in certain ethnic groups, or in groups of people with low income. In addition, some groups may be more sensitive to the presence of hazardous substances in the environment. Land use information is important because sensitive groups of people such as school children or residents in health care facilities may be located near the site. Use of some natural resources such as groundwater may have an impact on the potential for human exposure to hazardous substances.
In 1990, the total population within 1 mile of the site was 9,848 persons. Of this population, 19% were white, 80% were black, and 1% were other races. A total of 5,147 housing units are within 1 mile, and 892 children aged 6 and younger live within 1 mile (US Department of Commerce 1990). Appendix C presents a map of the area with demographic statistics.
The AGL site covers approximately 3.5 acres, consisting of three parcels (Northern, Southern, and Western) and the Third Level Canal. Southeastern Bituminous, a former asphalt production plant, was located adjacent to the site; cleanup of the Southeastern Bituminous site will occur concurrently with cleanup of the canal. Currently, the AGL site is surrounded by residential and commercial areas. The nearest residence is approximately 15 feet from the Southern Parcel. A small park is across the street from the Western Parcel. A church with a day-care center is located across from the Northern and Southern Parcels. Land use is typical of residential areas (e.g. gardens and playgrounds).
Gas manufacturing occurred at the site from 1852 through 1954. Land use before the 1800s is unknown. The Northern Parcel was used as an operations center for natural gas transfer until the mid 1980s. The Southern Parcel formerly housed a gas holding tank, which was dismantled in May 1997. The Western Parcel was used primarily for storing gravel and street rubble.
No future plans exist for the Southern Parcel, which is currently being seeded with grass. Future plans for the Western Parcel are uncertain. AGL is beginning to evaluate possible clean-up scenarios for the parcel, including various plans to dig and haul. Habitat for Humanity has expressed interest in building a house on the Western Parcel, and AGL may donate the property to that group. The Augusta Canal Authority is pursuing federal funding to turn the Third Level Canal into a historic site and would like to see the AGL-owned portion of the land donated to the Canal Authority. The Canal Authority may use the former office building on the Northern Parcel as part of a proposed tourist site.
Natural Resource Use
The city of Augusta receives drinking water from a municipal water system whose intake is located on the Savannah River, upstream from the site. To ATSDR's knowledge, no private drinking-water wells exist in the area. The RI identified two non-drinking-water wells within Augusta city limits, one used for cooling at a nursing home, and the other used for irrigation. The nursing home well is located approximately one mile west of the site; the location of the reported irrigation well could not be identified (Law Engineering and Environmental Services, Inc., 1996).
The Third Level Canal is the primary surface water body in the site's vicinity, although little water presently flows through the canal except during flood conditions. The canal was constructed in the 1840s as a tailrace (canal or ditch used for removal of waste products) for water-powered mills built on the Second Level Canal and was also meant to carry storm water, sanitary sewage, and other discharges away from the city center of Augusta (Remediation Technologies, Inc., 1997b). The canal does not currently serve as a tailrace because all water turbine installations on the Second Level Canal are out of service. The current function of the canal is as the main storm water drainage system for downtown Augusta. Canal water flows northwesterly west of 8th Street (toward the Savannah River flood gates) and southeasterly east of 8th Street (toward Phinizy Swamp). The Savannah River passes approximately 4,000 feet from the site (see Appendix A).
ATSDR believes identifying and addressing community health concerns relevant to this site is critically important to the Public Health Assessment. Community concerns were communicated during a community meeting attended by ATSDR staff, and through phone contact and letters. This section identifies community health concerns regarding possible health effects of this site.
Health Outcome Data
No health outcome data related to the site are available. According to Georgia's Emergency Management division, no health studies have been conducted.
The Department of Energy is sponsoring a cancer study of the Savannah River area adjacent to the Savannah River Plant, a nuclear production facility in Aiken, South Carolina. Richmond County, Georgia, is one of the targeted counties; however, the study only covers cancer data from 1991 to 1993 at the county level and is not specific to residents near the site. Therefore, county-level data will not likely provide practical health outcome data concerning the site's impact on area residents' health.
Community Health Concerns
During a meeting on January 30, 1997, parishioners of the CME Church voiced concerns about the general health status of residents of their neighborhood. The church is located on Taylor Street, across the street from the Southern and Northern Parcels of the site. Parishioners' concerns include:
- Skin problems (e.g., rashes; skin irritation; small, fine white bumps). One resident who lives across the street from the site complained of experiencing skin irritation and bumps on her hands after digging in her garden. She reported that dermal exposure consistently resulted in this rash. Her perception is that the site contaminated her soil.
- Problems with hot water. Several residents complained that their hot water taps expel a black, oily substance. Their perception is that the water problems are site-related.
- Surface water run-off contaminating residential vegetable gardens. Residents see black, oily water backing up the sewers and flowing down the streets during heavy rainstorms. Their perception is that the water is contaminated and that dermal exposure to the water or ingestion of food grown in the area could cause health problems. Houses in the area do not have basements because the water table is high, and residents complained that black, oily water leaked into their houses.
- Inhalation of site contaminants. An area resident complained of smelling an odor so strong that she could not breathe while walking past the site with her children. This resident has asthma and is concerned that her asthma may be exacerbated by the site's odor. Other residents complained of smelling terrible odors on the first day AGL began cleaning up the holding tank on the Southern Parcel. They continued to notice the odor during early morning hours.
- Eye problems such as cataracts and glaucoma. An area resident has had her cataracts operated on twice. She knows of several other people in the area who also have cataracts. Another resident's sister has glaucoma; their mother has both glaucoma and cataracts and has lost her sight in one eye. The residents are concerned that exposure to site-related contaminants is causing their eye problems.
- Reports of black tar oozing in area backyards. Area residents complain that they sometimes see tar oozing from the ground on their property on hot days. These reports have not been confirmed. Residents are concerned about possible health implications of being in contact with tar.
- High incidence of cancer and death in the neighborhood. Area residents are concerned that they might be experiencing a cancer cluster, but no data are available to support an inquiry. A house-to-house survey compiled reports of 42 deaths over the past 10 years from lung, throat, and other cancers. Residents want to know whether the cancer and deaths are site-related.
- Choking and burning sensation in lungs. A visiting pastor at the CME Church complained that site odors made her feel as if she were choking. The church then contacted area residents to see whether anyone else was experiencing health problems related to odors. Several residents complained of the odor but did not report any associated health effects. During a meeting with parishioners, several residents expressed concern about air pollution.
- Body pain. One resident complained of experiencing what he described as "full-body pain" and wondered whether it could be site-related.
For further discussions evaluating community health concerns, see the Community Concern Discussion section later in this document under Public Health Implications.
In this section, the available environmental monitoring data are presented. The tables in Appendix D list contaminants in each medium: soil, sediment, groundwater, and air. These contaminants are evaluated in subsequent sections of the public health assessment to determine whether exposure to them has public health significance. ATSDR selects and discusses contaminants based on several factors, including concentrations on- and off-site, comparison of on- and off-site concentrations with public health assessment comparison values for noncarcinogenic and carcinogenic endpoints, and community health concerns.
The listing of a contaminant in the tables does not mean that it will cause adverse health effects if exposure occurs at the specified concentrations. Contaminants included in the tables are further evaluated in this public health assessment. The potential for adverse health effects to result from exposure to contaminants of health concern is discussed in the Public Health Implications section.
Comparison values for ATSDR public health assessments are maximum concentrations of contaminants in a specific medium (e.g., soil, sediment, surface water, groundwater, air) that are not expected to produce an adverse health effect in people who are exposed. When the concentration of a contaminant detected on or off of the AGL site is above the comparison value it is selected for further evaluation to determine potential adverse health effects. See Appendix E for a description of the comparison values used in this public health assessment. ATSDR and other agencies developed these values as guidelines for estimating the media concentrations of contaminants that are unlikely to cause adverse health effects, given a standard daily ingestion rate and standard body weight. ATSDR considers both adults and children when developing comparison values, with the assumption that in certain situations children may be more sensitive and more exposed to contaminants. For example, children may come into contact with and ingest soil particles at higher rates than do adults; also some children with a behavior trait known as "pica" are more likely than others to ingest soil and other nonfood items.
The site hydrogeology (i.e., the type of soils/rock and water underlying the site) consists of a vertical sequence of fill material and sediments overlying saprolite rock (Remediation Technologies, Inc., 1997b). The saprolite grades into bedrock. Fill material is encountered at depths of up to 10 feet below ground surface (bgs) and comprises concrete, asphalt, demolition materials, and by-product-like material. Sediments extend from the ground surface to 15 to 25 feet bgs. The groundwater in the aquifer below the site generally flows east toward the Savannah River; groundwater discharge to the canal may occur at locations where the canal's water elevation falls below the groundwater elevation in the aquifer. Data in the RI indicates the depth to groundwater ranges approximately 4-16 feet bgs, depending on the location (Law Engineering and Environmental Services, Inc. 1996).
AGL originally installed 16 monitoring wells (MW-01 through MW-16) on the Northern and Southern Parcels. Three wells (MW-01, MW-02, and MW-03) were abandoned because free product was encountered during sampling. Subsequently, product was found in MW-8, MW-9, and MW-14 (Law Engineering and Environmental Services, Inc., 1996).
Groundwater was analyzed for EPA Target Compound List (TCL) volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs) (including polycyclic aromatic hydrocarbons [PAHs]), and inorganic compounds. The results of on-site groundwater sampling are summarized in Appendix D, Table 1. The contaminants identified during the sampling include benzene, PAHs (chrysene, fluoranthene, naphthalene, and pyrene), and arsenic. The highest benzene concentration (64,000 parts per billion [ppb]) was detected in Monitoring Well (MW)-12, which is located on the northeast corner of the Southern Parcel and within several feet of houses on King Street. Benzene was detected at 28,000 ppb in MW-13 and at 20,000 ppb at MW-6, both located at the northern edge of the Northern Parcel. The highest PAH concentrations were detected in MW-13 and MW-3 (also located on the Northern parcel). The community obtains their drinking water from a municipal source; residents are not drinking the groundwater, therefore, exposure through the groundwater is not a completed pathway.
Western Parcel Groundwater: AGL sampled three monitoring well and three geoprobe locations at various depths as part of Western Parcel investigations. Groundwater samples were analyzed for TCL VOCs, PAHs, and inorganic compounds. Table 2 (Appendix D) summarizes groundwater sampling data. Benzene, chloromethane, methylene chloride, styrene, toluene, naphthalene, lead, nickel, vanadium, and several other inorganic compounds were detected.
Two types of air monitoring were conducted at the perimeter of the Southern Parcel during the decommissioning of the gas holder: real-time monitoring and collection of time-weighted cumulative data. Real-time monitoring was used to evaluate noise, odor, and air emissions, and to protect workers and the adjacent residents. Airborne emissions of particulates, benzene, and naphthalene were measured using hand-held or portable instruments. AGL also collected perimeter samples (both upwind and downwind of the work area) on a continuous basis over an 8-hour period. These samples are reportedly representative of the daily average exposure of the community at the site perimeter. Benzene, toluene, ethylbenzene, and xylene (BTEX); PAHs; and lead were monitored during the RI. While the steel structure surrounding the gas holder was being dismantled, AGL monitored for particulates and lead in the ambient air. These data are summarized in Appendix D, Table 3. No other air data are available. Naphthalene at 0.01 parts per million (ppm) and benzene at 0.05 ppm were detected above the ATSDR comparison values of 0.002 ppm and 0.00003 ppm, respectively. No other contaminants were detected above available comparison values. AGL attributes a large part of these emissions to the exhaust from on-site power equipment rather than to any site-related contamination.
Surface water was sampled from the Third Level Canal during a 1992 Site Investigation and as part of the RI. Surface water samples were analyzed for VOCs, SVOCs, PAHs, and metals. The results are summarized in Appendix D, Table 4. Low levels of PAHs (less than 1 ppb) were detected in one sample. The community obtains their drinking water from a municipal source; residents would not be drinking the surface water, therefore, exposure through surface water is not a completed pathway.
Gas Holder Effluent
Gas Holder No. 5, located on the Southern Parcel, was a 1.5-million-cubic-foot gas holder containing a 27-foot-thick water layer. The 3 million gallons of water were pumped through a carbon filter in an on-site treatment system. This holder was dismantled in May 1997. The following is a summary of sampling data from the treatment system.
Average daily influent concentrations were reported at 134 ppb for benzene and 74 ppb for toluene. After passage through the treatment system, the water was discharged to the Publicly Owned Treatment Works (POTW). Benzene concentrations in the treatment system effluent during the first 20 days of system operation ranged from 1.2 to 69 ppb. On five occasions, during the next 8 days of operation, instantaneous concentrations of benzene were recorded in the effluent above the daily average concentration, ranging from 340 to 520 ppb. AGL believes the situations where average values were exceeded were caused by an increase in the influent concentration combined with excessive channeling within the carbon bed filter system. No subsequent excessive values were recorded. The daily average concentration limit for toluene was never exceeded.
Site investigations involved sampling sediment from various locations along the Third Level Canal, including active and non-active source discharge points. Sampling results are summarized in Appendix D, Table 5. Contaminants detected above soil comparison values for a pica child and child include VOCs (benzene, ethylbenzene), PAHs (benzo(a)pyrene, chrysene, fluoranthene, naphthalene, and pyrene), and inorganic compounds (arsenic, chromium, and lead). Soil comparison values for adults were exceeded for benzene, benzo(a)pyrene, chrysene, and lead. Lead was detected at 9,420 ppm. The majority of the highest detections occurred in samples collected adjacent to the Northern Parcel (SD-02 and SD-03). In 1992, fencing around the canal was reportedly extended, restricting access to the canal.
AGL collected seven samples of the tar-like material observed on the Northern and Southern Parcels, at depths ranging from 0.5 to 8 feet bgs. Samples were analyzed by the Toxicity Characteristics and Leaching Procedure (TCLP) to evaluate whether the material was considered "hazardous" under federal regulations. The results of these analyses are summarized in Appendix D, Table 6. The highest detected benzene concentrations were collected from samples below surface depths, although the tar-like material also was observed at surface locations.
During different phases of site investigations, AGL collected surface soil samples from the Northern, Southern, and Western Parcels at depths of approximately 0-2 feet bgs, including "screening" samples analyzed in an on-site laboratory for PAHs and selected VOCs. In addition, approximately 40 samples were analyzed in an off-site laboratory for VOCs, PAHs, and inorganic compounds. Appendix D, Table 7 summarizes surface soil sampling results for the Northern and Southern Parcels. PAHs were detected at concentrations ranging from not detected to 11,000 ppm. Benzene (maximum concentration: 130 ppm), benzo(a)pyrene (2,700 ppm), chrysene (3,500 ppm), fluoranthene (3,700 ppm), naphthalene (9,900 ppm), phenanthrene (11,000 ppm), pyrene (6,500 ppm), and arsenic (36.6 ppm) were detected above comparison values.
Western Parcel Surface Soil: AGL collected 30 surface soil samples at depths of approximately 0-2 feet bgs for laboratory analysis. Appendix D, Table 8 summarizes these results. PAH concentrations ranged from not detected to 75 ppm. Lead levels were detected up to 381 ppm, which is above GA EPD's conservative screening value of 75 pm, but below the GA EPD approved site-specific action level of 400 ppm.
AGL sampled numerous subsurface soil locations on-site at depths greater than 2 feet bgs. Appendix D, Table 9 summarizes on-site subsurface soil sampling results. Comparison values show that subsurface soil contaminants of concern include benzene (maximum concentration: 190 ppm), benzo(a)pyrene (400 ppm), chrysene (870 ppm), and naphthalene (8,600 ppm). Several metals were detected above comparison values, including lead at 5,400 ppm. The majority of the samples were collected on the Northern Parcel.
Western Parcel Subsurface Soil: AGL sampled subsurface soil from 25 locations on the Western Parcel at depths greater than 2 feet bgs. The results are summarized in Appendix D, Table 10. No comparison values exist for the contaminants detected (inorganics only), but the values fall within the range of typical background concentrations in the eastern United States (Shacklette and Boerngen, 1984).
AGL installed and sampled a total of 16 off-site monitoring wells. Off-site groundwater samples were analyzed for VOCs, PAHs, and inorganic compounds. Appendix D, Table 11 summarizes off-site groundwater sampling data. Benzene, chrysene, naphthalene, arsenic, and lead were detected. Some of the highest detections occurred in samples collected at monitoring wells down gradient from the canal. Because the community obtains their drinking water from a municipal source, exposure through the groundwater pathway is not complete, and residents are not expected to drink the off-site groundwater.
No off-site air monitoring was conducted.
One sample was taken from off-site (up gradient) surface water in the Third Level Canal. Appendix D, Table 12 summarizes the results. Methylene chloride was the only analyte detected that might be of concern if people ingested the water, however this is unlikely because community members obtain their drinking water from the municipal supply.
AGL also sampled several off-site surface soil locations at depths of approximately 0-2 feet bgs for VOCs, PAHs, and inorganic compounds. Appendix D, Table 13 summarizes the results. PAHs were found at relatively low concentrations, ranging from nondetect to 2.7 ppm. The highest concentrations occurred in samples collected in the vicinity of the church. Lead was detected at 7,290 ppm, significantly above the site-specific action level of 400 ppm. The highest lead detections occurred in samples collected in the vicinity of an Amoco station and an open, vacant lot. No data are available for soils located in specific residential yards.
AGL sampled multiple off-site subsurface soil locations at depths greater than 2 feet bgs. Sampling results are summarized in Appendix D, Table 14. PAH concentrations ranged from nondetect to 490 ppm. Lead was detected at 4,900 ppm. The majority of the samples were taken when monitoring wells were installed south/southwest of the Southern Parcel.
No off-site sediment samples were collected.
In preparing this public health assessment, ATSDR relied on information provided in reference documents. ATSDR assumes that adequate quality assurance and quality control measures were followed regarding chain of custody, laboratory procedures, and data reporting, unless otherwise stated.
According to AGL personnel, the site has always been fenced. In 1992, the fence was extended to the canal, thereby limiting access to the site. ATSDR observed evidence of trespassing during its site visit in January 1997. No physical hazards were noted during the site visit on the Northern and Southern Parcels. A large amount of building debris and rubble was observed on the Western Parcel that could constitute physical hazards if people had access to it. The Third Level Canal has a steep bank and a narrow passage between the chain-link fence and the bank.
To determine whether people were exposed to contaminants originating from the AGL site, ATSDR evaluated the environmental and human components that lead to human exposure. This pathways analysis consists of five elements:
- Source of contamination
- Environmental medium in which the contaminants may be present or may migrate
- Points of human exposure
- Routes of human exposure such as ingestion, inhalation, or dermal exposure
- Receptor population
ATSDR identifies exposure pathways as completed, potential, or eliminated. An exposure pathway is complete in the past, present, or future if all five elements of an exposure pathway link the contaminant source to a receptor population. Potential pathways, however, are defined as situations in which at least one of the five elements is missing, but could exist. Potential pathways indicate that exposure to a contaminant could have occurred in the past, could be occurring now, or could occur in the future. Eliminated exposure pathways are those where site characteristics make past, current, and future exposure through the pathway extremely unlikely. All completed, potential, and eliminated exposure pathways for this public health assessment are presented in Appendix F.
On-site Sediment: Ingestion and Dermal Contact
Canal sediment contains elevated levels of arsenic, benzene, chromium, ethylbenzene, lead, and PAHs (benzo(a)pyrene, chrysene, fluoranthene, naphthalene, and pyrene). Evidence of trespassing was observed during ATSDR's site visit in 1997, though the site is fenced. Possible exposure routes include ingestion of and dermal contact with contaminated sediment. Access to the sediment is greatly limited by the steep slope of the canal bank. It is unlikely, though plausible, that trespassers and workers contacted sediment in the canal. Therefore, although this is a completed pathway, exposure is expected to be minimal. In addition, it is highly unlikely that small children came or would come in contact with canal sediments.
On-Site Surface Soil: Ingestion and Dermal Contact
On-site workers and trespassers on the AGL property were likely exposed via ingestion and dermal contact to elevated levels of arsenic, benzo(a)pyrene, chromium, chrysene, cyanide, fluoranthene, lead, naphthalene, phenanthrene, and pyrene on an intermittent basis in the past. Most of the highest detections occurred in samples collected on the Southern Parcel, which is in close proximity to several residential properties. Although the fence restricts access, evidence of trespassing still exists.
On-Site Surface Water: Dermal Contact
ATSDR also assumes that, in the past, when surface water was present in the canal (e.g., during flood conditions) trespassers on the AGL property were exposed to elevated levels of benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, chrysene, and methylene chloride. The intermittent exposure route is through dermal contact with contaminated water in the past. However, little or no surface water is presently in the canal, except during flooding conditions. The RI describes the canal as being "silted in" and overgrown. It is unlikely that trespassers were exposed to sufficient amounts of surface water to cause adverse health effects.
Off-Site Surface Soil: Ingestion and Dermal Contact
ATSDR assumes that area residents are exposed to contaminated soils on adjacent properties. AGL sampled surface soil off-site at depths of approximately 0-2 feet primarily from rights of way. Sampling revealed the presence of arsenic, benzo(a)pyrene, chromium, chrysene, and lead. The highest concentrations of PAHs (2.7 ppm,) occurred primarily in samples collected on Block E, in the vicinity of the CME Church. The highest lead detection (7,290 ppm) was sampled on Block A. During the ATSDR site visit, an Amoco gasoline station and a vacant lot were observed in Block A. Exposure routes include ingestion and dermal contact with the soils by neighborhood children, gardeners, etc.
While the Gas Holder No. 5 was being removed, AGL collected air samples along the perimeter of the Southern parcel. Benzene, naphthalene, toluene, and xylene were detected on-site, at the perimeter. The gas holder has been removed, and this source of contaminant release is no longer present. Area residents complained of foul odors while the gas holder was being removed. It is therefore assumed that workers and nearby residents could have been exposed to air contaminants during that time. No other air data are available.
Arsenic, benzene, chrysene, lead, and naphthalene were detected in off-site groundwater. No one drinks this water because all of Augusta uses municipal water. People have expressed concern, however, about exposure to occasional flood waters in the vicinity of the site. If groundwater contributes to these flood waters, concentrations of contaminants in groundwater would likely be diluted. In addition, the canal serves as a conduit and should drain flood water away from the neighborhood. People's contact with any flood water is expected to be sporadic and limited. Nonetheless, it represents a potential exposure pathway that ATSDR examined.
Off-Site Surface Water
Methylene chloride was detected in off-site surface water, upstream from the site. Although this area of the canal is accessible to area residents, it is unlikely that exposure to the water will occur often enough to cause adverse health effects.
Current and future exposure to on-site sediment is considered only a potential exposure pathway because access to the sediment is limited by both a fence and the steep incline of the canal's bank. Elevated levels of arsenic, benzene, benzo(a)pyrene, chromium, chrysene, ethyl benzene, fluoranthene, lead, naphthalene, and pyrene were detected. Exposure in the present and future is unlikely, however, because the site is fenced and access limited.
Off-Site Groundwater (Ingestion)
Arsenic, benzene, chrysene, fluoranthene, methylene chloride, naphthalene, and pyrene were detected in groundwater off-site. However, because residents in Augusta receive municipal drinking water supplies, no one uses or is exposed to groundwater below or near the site. Thus this pathway has been eliminated from further analysis.
On-site Surface Water
Benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, chrysene, and methylene chloride were detected in on-site surface water from the canal. During ATSDR's site visit and during the remedial investigation, the canal was observed to be stagnant, thus this pathway has been eliminated from further analysis. Not enough water is present in the canal to constitute a current or potential future exposure pathway.
On-Site Subsurface Soil
Arsenic, benzene, benzo(a)pyrene, chromium, chrysene, cyanide, ethylbenzene, fluoranthene, lead, naphthalene, pyrene, and toluene were detected in on-site subsurface soil at depths greater than 2 feet bgs. This pathway has been eliminated from further analysis because people are not expected to be exposed to subsurface contamination.
Off-Site Subsurface Soil
Arsenic, benzo(a)pyrene, chromium, chrysene, fluoranthene, lead, naphthalene, and pyrene were detected in off-site subsurface soil. The maximum detections were taken 4-6 feet bgs. This pathway has been eliminated from further analysis because it is unlikely that area residents would come in contact with subsurface soil. However, testing of residential soils has been recommended.
In this section, ATSDR discusses the adverse health effects that could plausibly result from exposures to site contaminants. Although the relative toxicity of a chemical is important, the response of the human body to chemical exposure is actually determined by several additional factors, including the magnitude of exposure (how much), the duration of exposure (how long), and the route of exposure (i.e., breathing, eating, drinking, or skin contact). Lifestyle factors (i.e., occupation and personal habits) have a major impact on the likelihood, magnitude, and duration of exposure. In addition, individual characteristics such as age, sex, nutritional status, overall health, and genetic constitution affect how a contaminant is absorbed, distributed, metabolized, and eliminated from the body. In short, the probability that exposure-related adverse health outcomes will actually occur does not depend solely on concentrations in environmental media.
Using available scientific data, much of which the agency has collected in its Toxicological Profiles, ATSDR has determined concentrations of chemicals that can reasonably (and conservatively) be regarded as harmless, assuming default conditions of exposure. The resulting comparison values and health guidelines generally include ample safety factors to ensure protection of sensitive populations. They are used to screen contaminant concentrations at a site and to select so-called "chemicals of concern" that warrant closer scrutiny by agency health assessors and toxicologists. A "chemical of concern" is defined as any chemical that is detected in air, water, or soil at concentrations that exceed one or more of ATSDR's comparison values. (See Appendix E for a more complete description of ATSDR's comparison values, health guidelines, and other values ATSDR uses to screen site contaminants.)
It cannot be emphasized strongly enough, however, that comparison values are not thresholds of toxicity. Although concentrations at or below a relevant comparison value may reasonably be considered safe, it does not necessarily follow that any concentration that exceeds a comparison value would be expected to produce adverse health effects. Indeed, the whole purpose behind highly conservative, health-based standards and guidelines is to enable health professionals to recognize and resolve potential public health problems before that potential is realized.
Chemicals of Concern at AGL
The "chemicals of concern" detected at AGL are PAHs and metals (including arsenic, chromium, and lead) in on- and off-site soils and on-site sediment, and PAHs detected in on-site surface water. Benzene, detected in on-site sediment and air samples, is also a chemical of concern.
A public health hazard exists only if people are exposed to the contaminated media and the potential exposure doses may be high enough to produce adverse health effects. In many cases, contaminant levels detected on-site exceeded child or pica comparison values only, indicating that contaminants are not of public health concern if only adult exposures exist. To evaluate the likelihood, if any, of the chemicals of concern at the AGL site causing adverse health effects to the people described in the preceding Pathways Analysis section, ATSDR estimated the dose of these chemicals to which individuals might be exposed, and compared them to doses reported in the scientific literature to be associated with either carcinogenic or non-carcinogenic adverse health effects.
Polycyclic Aromatic Hydrocarbons
Polycyclic aromatic hydrocarbons are generally found in mixtures within the waste products of burned coal, oil, gas, or other organic substances. Approximately 20 different PAHs are commonly found in the environment. PAHs detected at the AGL site include benzo(a)pyrene, benzo(a)anthracene, benzo(b)fluoranthene, chrysene, fluoranthene, naphthalene, and pyrene. Some of these PAHs have been shown to cause cancer in experimental studies, others have not. Benzo(a)pyrene is thought to be the most potent (strongest) naturally-occurring carcinogenic PAH. Fluoranthene, naphthalene, and pyrene have not been demonstrated to induce cancer in animals or humans.
PAHs can enter an individual's body when a person ingests or contacts PAH-contaminated water, soil, and/or sediment or breathes air that contains PAHs. Inhalation studies of animals exposed to concentrations of 9.5 mg/m3 of benzo(a)pyrene showed an association between benzo(a)pyrene and cancer (ATSDR, 1995a). The PAHs detected in air samples at the AGL site, however, included only noncarcinogenic PAHs (naphthalene, fluorene, and phenanthrene) and were present at low concentrations (not detected to 0.05 mg/m3 [0.01 ppm]). The PAHs detected in air, therefore, do not pose a public health concern.
ATSDR estimated exposure doses for individuals who might be exposed to PAHs at levels detected in soils and sediment at and around the AGL site. Evaluation of the public health significance of PAHs found in on- and off-site soils and sediment is presented below.
Noncancer Effects: ATSDR developed a conservative scenario for estimating potential exposures to PAHs in soils and sediment from skin contact and ingestion. PAH concentrations ranged from not detected to 11,000 ppm (phenanthrene), with the highest concentrations detected on-site. Trespassers and workers were assumed to come in contact with the most contaminated soils for periods of 7 and 30 years, respectively. ATSDR concludes, using available sampling data, that exposure to PAHs in soils is not associated with acute or chronic noncancer effects because site-specific exposure doses are less than noncancer health guidelines. Exposures to PAHs in canal sediment are assumed to be much less than exposures to soil because of their inaccessibility. Limited past exposures to PAHs in canal sediment, therefore, are not of public health concern. In addition, exposure to the levels of PAHs detected in off-site soils is not likely to result in adverse health effects.
Cancer Effects: Assuming the same scenario described above, ATSDR evaluated the potential for carcinogenic effects associated with exposure to PAHs in soils and sediment. The conservative exposure assumptions described above indicate that no likelihood for excess cancers exists.
Benzene is a component of coal tar, crude oil, and gasoline. Because benzene is relatively volatile (i.e., it moves easily into air), inhalation can be a primary route of exposure. Exposure to benzene can also result from ingesting contaminated drinking water or from contact with contaminated soil/sediment. Very little information is available pertaining to human health effects associated with the ingestion of benzene. Direct contact with liquid benzene may cause irritation to the skin (Sandmeyer, 1981).
Benzene was detected in AGL on-site soil, sediment, air, groundwater, and in the tar-like material observed on-site. Benzene was not detected in soil samples collected off-site. As with PAHs, ATSDR evaluated the likely amount of benzene that individuals might be exposed to and estimated exposure doses based on conservative exposure scenarios. ATSDR assumed that people have in the past, or might in the future, come into contact with benzene-contaminated soil, sediment, tar-like material, and groundwater, or that people have in the past breathed benzene in the air. The results of this evaluation are presented below.
Soil/sediment/tar-like material: If workers or trespassers contacted soil/sediment/tar that contained maximum detected concentrations of benzene, these potential exposures were expected to have been infrequent and of short duration and to be of no public health concern. Furthermore, the benzene detected in tar samples (see Table 6) was "extracted" under laboratory conditions, and benzene found in the environment is bound up in the tar-like material and not in a form that is directly available to individuals coming in contact with the material. ATSDR will evaluate any future data that may be available on residential properties.
Groundwater: To be conservative, ATSDR assumed that a resident might come in contact with benzene detected in area groundwater, which ranged from not detected to 64,000 ppb on-site and from not detected to 3 ppb off-site. As stated previously, groundwater is not used for drinking purposes in the AGL area. Although exposure to the maximum concentrations of benzene detected in on-site groundwater samples would be potentially hazardous to health if that water were used for drinking purposes, no such hazard currently exists due to the absence of exposure. However, because the city of Augusta has no institutional controls in place regarding the installation and use of groundwater wells, the potential for future exposure to contaminated groundwater cannot be ruled out.
Air: Available air data are limited to samples collected at the perimeter of the site during the 5-month period in which AGL pumped, dismantled, and removed Gas Holder No. 5, formerly located on the Southern Parcel. No samples were collected beyond the perimeter of the site. Benzene concentrations measured in the perimeter samples ranged from not detected up to 157 µg/m3 (or 0.05 ppm). The highest concentrations were detected when the tank was being pumped (March/April 1997). The current occupational health standard for benzene is 1 ppm (1,000 ppb) in air, which means that workers can be exposed to that level for 8 hours a day, 40 days a week, without experiencing adverse health effects. The maximum air concentration measured at AGL is equivalent to ATSDR's acute EMEG of 50 ppb which is based on effects observed in mice and contains a safety factor of 300. This maximum is much lower than the high concentrations (700 to 3,000 ppm) of benzene in air, reported to possibly cause acute affects such as drowsiness, dizziness, rapid heart rate, headaches, tremors, confusion, and sometime unconsciousness in humans (ATSDR, 1995b). ATSDR considers that no acute, adverse health effects are likely to occur at the highest concentration of benzene reported at the AGL site.
Chronic effects are more difficult to assess. Air data exist only for a limited period of time. No other air data are available (for example, the concentration of benzene in air in the past, during historical operations of the AGL facility). Benzene was detected in air for a period of approximately two months, suggesting that disturbance of materials in the holder resulted in the highest emissions of benzene. Assuming area residents were exposed to benzene at detected levels for only this limited period of time, these exposures would represent no plausible cancer hazard to exposed residents.
Possible sources of elevated lead levels in the environment include lead-containing automobile exhaust, industrial emissions, and lead-based paint. It is not uncommon for soils next to well-traveled roadways to contain lead levels between 30 and 2,000 ppm and soils next to houses with exterior lead-based paint may have lead levels greater than 10,000 ppm (ATSDR, 1993a).
Lead was detected on-site in surface soils at concentrations up to 381 ppm. Lead concentrations were as high as 9,420 ppm in canal sediment. Although no lead screening data for children living near the site were available for review, small children, i.e., those most likely to exhibit pica or geophagic (soil-eating) behavior, are unlikely to be exposed to on-site soils and sediment.
Off-site sampling was limited primarily to street right-of-ways and open lots. Lead was detected off-site at one location (Block A, near a gas station) at a concentration of 7,290 ppm. Lead concentrations in soil collected on the nearby church property were relatively low, ranging from 14.4 to 487 ppm. These values are somewhat higher than lead levels in background soils of the Eastern United States which range from less than 10 to 300 ppm (Shacklette and Boerngen, 1984). However, the source of the lead detected in area soils cannot be determined on the basis of the available monitoring data and further testing of residential soil is recommended.
Other Metals in AGL Soil, Water, and Sediment
Arsenic: Experimental studies indicate that ingestion of arsenic-contaminated soil is more likely to contribute to the overall non-occupational uptake of arsenic than either skin contact or inhalation exposures (ATSDR, 1993b). ATSDR, therefore, focussed on the potential incidental ingestion of on-site and off-site soils by site trespassers/workers and nearby residents. Arsenic detected in on-site soils (36.6 ppm) and sediment (62.1 ppm) was not present at concentrations exceeding the health guideline for adults (i.e., less than ATSDR's chronic EMEG of 200 ppm). Although the pica and child EMEG's for arsenic were exceeded, small children are not likely to have been exposed to on-site soils or sediment in the past, nor are they expected to be exposed presently or in the future.
The range of arsenic concentrations detected off-site (0.19-8.2 ppb) is below ATSDR's EMEGs for both children and adults. Therefore, the arsenic levels in contaminated soils off-site do not pose any public health hazard to residents.
Chromium: Chromium III, the most common form of chromium in the environment, is an essential nutrient, but another form of chromium, chromiumVI, is potentially toxic, if the dose is high enough. However, since the human body readily converts chromium VI into chromium III, adverse effects are seldom seen outside of worker populations that have been exposed by inhalation of high levels for prolonged periods of time (ATSDR, 1993c). The levels of chromium in on-site and off-site soils are far too low to produce adverse health effects and do not pose any public health concern. Chromium was detected in on-site soils at concentrations that only slightly exceeded health guidelines for pica children and are well below EMEGs for children and adults. Chromium concentrations in off-site soils were even lower.
- Skin problems (e.g., rashes; skin irritation; small, fine white bumps) and reports of black tar oozing in area backyards.
- Concern regarding the condition of municipal water lines and the belief that contamination is entering the water pipes through old and cracked lines.
- Surface water run-off contaminating residential vegetable gardens.
- Inhalation of site contaminants and choking and burning sensation in lungs.
- Eye problems such as cataracts and glaucoma.
- High incidence of cancer and death in the neighborhood.
Although certain AGL contaminants of concern (e.g., benzene and PAHs) are associated with skin irritation, ATSDR's evaluation of available sediment and surface soil data suggests that exposure to detected concentrations are not likely to be associated with adverse health effects. However, only limited off-site soil data are available and no off-site "product" has been identified or sampled by investigators. High concentrations of benzene were detected in the "leachate" of one sample of the tar-like material sampled on-site. Benzo(a)pyrene has been shown in experimental studies to cause skin irritation in humans and workers exposed to PAH mixtures (e.g., coal tar). These individuals experienced skin conditions including chronic dermatitis and hyperkeratosis (EPA, 1988). The exposure levels required to produce such effects are generally much higher than those estimated to exist in the general environment.
Some residents, whose homes are all connected to the municipal water supply, have explained that their hot water taps expel a black, oily substance. Water from residential taps has not been sampled. However, water being pumped through the pipes is primarily under positive pressure; if cracks in the pipes exist, water would tend to flow out of the pipes rather than allow substances to flow into the pipes (Fonk, 1997). Following any maintenance of the municipal water system, residents are encouraged to let their tap water run for short periods to flush out possible impurities (sediment, rust) that could be present in the pipes and were loosened during maintenance of the line. However, sampling tap water at these residences is recommended.
No soil samples were taken from the yards of nearby residences or home gardens; soil samples came primarily from roadside areas and from locations on semi-private lots. In general, off-site surface soil sampling did not reveal significant amounts of tar-related compounds. PAHs were detected at concentrations up to 2.7 ppm. Lead was detected as high as 7, 290 ppm in one sample taken near the gas station. However, this is not necessarily an "abnormal" concentration for gas stations. Only limited uptake of PAHs and lead from soil by plants is possible (ATSDR, 1995a).
In general, risk of exposure to contaminants in soil from gardening activities is from soil brought into homes on shoes, clothing, children's hands and from soil adhering to the outsides of roots and leaves of plants. To minimize the amount of soil brought into homes, it is generally recommended to clean hands after playing and gardening, especially children's hands, and to remove soil that may adhere to plants by rinsing all garden-grown crops well with water. As additional soil data become available, ATSDR will evaluate expected uptake and possible health effects associated with this exposure route.
An area resident complained of smelling an odor so strong that she could not breathe while walking with her children past the site. Since the time of that complaint, the gas holder on the Southern Parcel has been removed. Perimeter air monitoring data collected during the 5-month period when the gas holder was being dismantled showed levels of benzene up to 0.05 ppm. Such levels are not likely to be associated with acute adverse health effects, and people cannot typically begin to smell benzene until concentrations reach 1.5-4.7 ppm. No other contaminants detected in air samples at that time (low concentrations of toluene, xylene, PAHs, and lead) would be expected to result in adverse health effects.
Based on a review of available literature, ATSDR concludes that none of the primary contaminants of concern at the AGL site would be expected to cause eye damage of any sort, including cataracts and glaucoma. Chromium, which was not detected at AGL at concentrations associated with adverse health effects, has been shown to cause eye injuries only in cases of direct contact with chromium solutions in occupational settings (ATSDR, 1993c).
No health outcome data exist on cancer incidence in the area surrounding the site. Environmental sampling data from the site detected elevated amounts of some carcinogenic contaminants, including certain PAHs and benzene. However, review of the available data suggests no currently plausible link between the contaminant levels to which area residents were exposed and any excess incidence of cancer. ATSDR has recommended the collection of additional off-site sampling data. ATSDR will review new data as it becomes available.
From the information reviewed, ATSDR concludes:
- Based on ATSDR's review of available data on current levels of contaminants detected on and off-site and exposure potentials, the AGL site represents no apparent health hazard for current and future exposures. However, because exposures to contaminants in the past are plausible, although information is not available, the site represents an indeterminant public health hazard for past exposures.
- Exposure (present, past, and future) to contaminants detected in the canal poses no apparent public health hazard. Although environmental sampling data revealed elevated concentrations of contaminants in sediment and surface water in the canal on the AGL site, people are not likely to contact canal sediment and surface water because of its inaccessibility. Furthermore, water is seldom present in the canal. Assuming limited exposures, the dose to which people might be exposed is not expected to be of health concern.
- Exposure (present, past, and future) to soil contaminants is unlikely to result in adverse health effects. Site trespassers and past workers are assumed to have been exposed for short durations to PAHs and metals in on-site soils, but the doses to which people might have been exposed are not expected to be significant.
- Although off-site soil sampling in the general vicinity of AGL revealed the presence of a limited number of PAHs and metals, the amount of contamination that people are expected to be exposed to, except for lead, is not likely to result in adverse health effects. The source of lead in surface soils is unidentified and represents a data gap. Further sampling of off-site soils would better define the extent of lead contamination and the potential for exposure.
- Available air data show that short-term exposure (during decommissioning of the gas holder in 1997) to measured air contaminant concentrations poses no apparent public health concern. This is because the release was of the limited time and off-site air concentrations would be expected to be even lower than those measured at the site perimeter. The extent of potential long-term past exposure to air contaminants is not known because historical air data are not available.
- Residents, in general, are not exposed to the area's contaminated groundwater (benzene, PAHs, and metals) because homes are connected to the municipal water supply. Residents' concerns are reasonable regarding exposure to contaminants when their homes flood during periods of high water, but because exposure is sporadic and short-term, adverse health effects are not likely. However, sampling of residential taps, where it is reported that a black oily substance is coming from the hot water tap, is recommended.
- The extent of human exposure to the tar-like material ("product") observed on-site is uncertain. Available testing results indicate that benzene is a primary component of this material. Limited exposure is not expected to be associated with adverse health effects. Although residents report black tar "oozing" onto their properties, no documentation of such events exists; this represents a data gap.
ATSDR makes the following recommendations to protect the health of area residents:
- Perform additional off-site surface soil sampling to more fully characterize contamination in residential yards. Evaluate the extent of lead contamination in soil and the reported black tar on residential properties.
- Provide health education regarding exposures to lead in the environment and home.
- Restrict access to the Third Level Canal and the former Southeastern Bituminous plant by fencing the area.
- Although no documented use of nearby groundwater wells exists, prohibit development and use of groundwater wells in the future to prevent the use of contaminated groundwater for household, industrial, or irrigation purposes.
- Present results of the public health assessment to the community and follow up with an availability session to discuss any remaining community health concerns.
- Inform residents of potential health effects associated with contaminated groundwater, soils, sediment, and air.
- Distribute ATSDR's findings widely to inform residents who may be leaving the neighborhood soon.
- Sample residential water taps where it was reported that a black, oily substance was expelled from the hot water taps.
In accordance with the Comprehension Environmental Response Compensation and Liability Act of 1980 as amended, ATSDR evaluates available environmental data, health outcome data and community concerns regarding potential exposures to hazardous contaminants, in the form of Public Health Assessments and Public Health Consultations. Based on conclusions from the health assessment or consultation(s) including; the identification of an exposed population, levels of contaminants at public health concern, a completed exposure pathway, and community concerns, follow-up health activities may be recommended by ATSDR Divisions of Health Assessment and Consultation, Health Education and Promotion, Health Studies, and Toxicology. Following review of the site documents, community concerns and ATSDR recommendations, further follow up activities many not be implemented.
The Public Health Action Plan (PHAP) for the AGL site contains a description of actions to be taken by ATSDR at and in the vicinity of the site following the completion of this public health assessment. For actions already taken at the site, please see the BACKGROUND section of this Public Health Assessment. The PHAP is designed to ensure that this public health assessment not only identifies public health hazards but provides a plan of action to mitigate and prevent adverse human health effects resulting from exposure to hazardous substances in the environment.
ATSDR includes a commitment to follow up on this plan and ensure that it is implemented. Public health actions to be implemented by ATSDR are:
- ATSDR will provide education to community and health professionals as needed.
- ATSDR will continue to review environmental sampling data as it is made available.
Adele M. Childress, Ph.D., MSPH
Environmental Health Scientist
Exposure Investigation and Consultation Branch/Petition Response Section
Division of Health Assessment and Consultation, ATSDR
Danielle Langmann, MS
Environmental Health Scientist
Exposure Investigation and Consultation Branch/Petition Response Section
Division of Health Assessment and Consultation, ATSDR
Frank Schnell, Ph.D., DABT
Exposure Investigation and Consultation Branch/Petition Response Section
Division of Health Assessment and Consultation
ATSDR Sr. Regional Representative
EPA Region 4
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