PUBLIC HEALTH ASSESSMENT
CAPITOL CITY PLUME
Montgomery, Montgomery County, Alabama
CERCLIS No. AL0001058056
December 2, 2004
Alabama Department of Public Health
Under a Cooperative Agreement with
Agency for Toxic Substances and Disease Registry
On the basis of this assessment, ADPH concludes the following:
- Currently, no residential or municipal wells that are still in use are known to be contaminated. Therefore, ADPH concludes that the CCP site currently represents No Apparent Public Health Hazard to residents with regard to drinking water because since no known exposure via drinking water is believed to be occurring.
- In 1991 and 1992, water analyses of Well 9 W by the Montgomery Water Works and Sanitary Sewer Board (MWWSSB) detected tetrachloroethylene (PCE) at levels above the maximum contaminant level (MCL) for drinking water. ADPH understands that the well was taken out of service in 1992. Therefore, ADPH concludes that the CCP site represented No Apparent Public Health Hazard in the past. This is due to the quick response by MWWSSB in removing the well from service. Any contaminants that may have been present would have been greatly diluted due to blending in the Montgomery water supply system.
- If the plume is left unchecked and no remedial action is taken, the contaminated plume could possibly continue to migrate toward the North Well Field (NWF). Well number 2, 18, and 20, screened in the shallow aquifer, are used during periods of drought. These wells could potentially be affected in the future if remedial activities on the plume are not completed. Improperly constructed or improperly abandoned wells in the NWF may serve as conduits for water from the shallow aquifer to migrate downward into the deeper aquifers. Although possible, it is unlikely that the plume would reach NWF because the low-lying area, where Cypress Creek enters Cypress Inlet along the bank of the Alabama River, would interrupt flow in this direction. Surface and subsurface water from the north and south sides of Cypress Creek appear to enter the Alabama River at this low-lying area.
- In 1993, excavation workers at the Retirement Systems of Alabama (RSA) Energy Plant construction site experienced a completed acute exposure pathway to PCE and trichloroethylene (TCE) in groundwater and subsurface soil. ADPH concludes that the CCP site represents No Apparent Public Health Hazard to these workers because the duration of exposure was short and no lasting health effects occurred. However, business, real estate, and government professionals anticipate further downtown and riverfront development, thus creating the potential for future exposures for excavation workers. The CCP site was determined to represent an Indeterminate Public Health Hazard to future excavation workers because potential contaminant levels and exposure duration are not known at this time.
- Workers who use a shallow-groundwater industrial well for daily vehicle washing operations could have been potentially exposed to PCE and TCE. ADPH is unaware of any health condition(s), among these workers which could be associated with these contaminants, and ADPH concludes that the CCP site currently poses No Apparent Public Health Hazard.
- Contaminated groundwater is approximately 50 feet below ground surface (bgs), and vapor intrusion is unlikely at this site.
Pre-excavation sampling should be conducted at future excavation sites to identify the presence of any contamination. Workers employed at contaminated sites should have proper Occupational Safety and Health Administration (OSHA) training and follow applicable OSHA guidelines to prevent the possibility of exposure to contamination.
MWWSSB tests the city drinking water on a daily basis using state and Federal Water Quality Standards to assure the drinking water is safe for the public. Periodic sampling of the EPA wells and the NWF should continue to monitor for the presence of contaminants. Regardless of whether contaminants are detected, the results should be forwarded to ADPH for evaluation and for inclusion into the site administrative record. Additionally, the industrial well should continue to be sampled to identify and quantify any contaminants, as well as the potential exposure to contaminated groundwater used for washing operations. Whether or not contaminants are detected, the results should be forwarded to ADPH for evaluation and for inclusion into the site administrative record.
A survey was not conducted to locate any existing basements within the area known to be contaminated. Owners of residences with basements should call the Montgomery Fire Department, the Alabama Department of Environmental Management (ADEM), and the ADPH if vapors or odors are detected in a basement.
If you have questions or comments after reading this report, please contact
Phyllis Mardis, Public Health Senior Environmentalist
Alabama Department of Public Health
Environmental data are results of laboratory testing of samples of environmental media (i.e., air, soil, water, or food taken from a site location. These data show the date and location of samples, specific contaminants present, and the amount (or concentration) of those contaminants. If people could come in contact with any contaminated media, the concentrations can be used to determine whether sufficient contaminants could enter the body to cause adverse health effects.
Information About the Community
Information about the community includes the facilities used by the public, demographics, and public input. This information identifies 1) activities that could bring people into contact with contaminated media, 2) environmental health education needs, and 3) specific health problems or certain events about which people are concerned. ADPH evaluates whether health concerns could be related to the site and focuses on any specific illnesses that are toxicologically related to exposures at the site.
Health Outcome Data
Health outcome data are rates of some diseases or health conditions physicians have reported for their patients, which are linked to the patient's residential address, to determine if something in the area may be causing a health hazard. These data can sometimes help determine whether people at a site are experiencing more disease than expected amount. However, CCP workers, who live in at least six different counties, comprise the majority of the site population. Therefore, health outcome data accurately describing the health status of the occupationally exposed CCP-site population are not available.
This public health assessment will provide information on 1) selected site-related contamination, 2) the potential for public contact with contaminants, 3) the public health implications of contact, and 4) how to protect public health. Please see Appendix D for a glossary of environmental terms.
Site Description and Location
The CCP hazardous waste site is located in downtown Montgomery, Alabama (Figure 1). A hazardous waste site is a place where hazardous substances have been released into the environment, and under certain conditions, might be harmful to people who come into contact with these substances. The CCP site consists of one or more contaminated groundwater plumes.
- Groundwater-When rain falls to the ground, the water does not stop moving. Some of it flows along the surface in ditches, streams, or lakes, some of it is used by plants' some evaporates and returns to the atmosphere, and some sinks into the ground. Groundwater is the water that sinks into the ground, filling the spaces around underground soil, sand, and rock.
- Groundwater plume-A groundwater plume is a line or column of underground water that contains chemical(s). A plume usually moves away from the place the contaminant(s) entered the water and toward other areas.
The CCP-site area is estimated to include at least 30 square blocks. A larger area targeted for public health interest more than doubles the geographic area. For this public health assessment, the CCP site includes the EPA area of investigation, plus an expanded buffer zone in the direction of groundwater flow. The area reviewed in this public health assessment also encompasses the municipal wells in north Montgomery (Figure 2).
The ground surface at the site is highest at the southeastern end, sloping downward to its lowest point at the Alabama River at the northwest end of the site. The high end is approximately 290 feet above mean sea level and drops to approximately 170 feet within 0.3 miles. The ground surface then slopes more gradually to approximately 165 feet at the river (3). Surface water runoff is collected by a storm sewer system that was built in approximately 1860. No description or diagram of the storm sewer system is available, but MWWSSB reports that all sewer lines in the area empty into the Alabama River (2).
The CCP site is located over an alluvial aquifer of sandy clay and gravel residuum that could range from 30 to 80 feet bgs. The aquifer is highly permeable, meaning that rainwater not captured by the storm sewer system can quickly sink into the ground. Below the alluvial aquifer is the Eutaw Formation. The Eutaw Formation is hydraulically connected to the alluvial aquifer, meaning that water from the alluvial aquifer also can sink readily into the Eutaw Formation (2). The alluvial aquifer and the Eutaw Formation, together, also may be called the shallow aquifer. Groundwater in the shallow aquifer flows from the southeast to the north northwest, toward the river. At the bottom of the Eutaw Formation, a layer of sandy clay separates the formation from the Gordo Formation below. This confining layer might prevent water in the shallow aquifer from sinking into the Gordo Formation. The Gordo Formation also is an aquifer, and groundwater flow is from the southeast to the northwest within the aquifer (4).
Site and Investigation History
In 1993, soil containing PCE was excavated during construction of the Retirement Systems of Alabama (RSA) Tower Energy Plant. The soil was removed and disposed of properly. The discovery of PCE in soil prompted the Alabama Department of Environmental Management (ADEM) to conduct a preliminary assessment of the area near the construction site, in accordance with the provisions of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). CERCLA is a federal law concerning hazardous substances in the environment and protection of public health. The ADEM Preliminary Assessment, dated February 1995, concluded that groundwater at the site was contaminated with PCE (5).
In 1991 and 1992, MWWSSB detected PCE in Municipal Well 9 W. The well was taken out of service to protect the city's drinking water system. Well 9 E is next to Well 9 W and is approximately the same depth. Well 9 E also was removed from service in 1997 because of contamination and the structural condition of the well (5).
In 1996, ADEM performed a site investigation to assess the threat to human health and the environment. ADEM concluded that the site could pose a serious threat to much of Montgomery's north and west well fields. These wells have been reported to provide as much as 34 percent of Montgomery's water supply. The ADEM Site Investigation report, dated March 1996, recommended that EPA evaluate the site further under CERCLA (5).
In 1999, MWWSSB conducted an investigation of groundwater and the storm-water system in the downtown area and found similar contamination in groundwater (5). In 2000, EPA began a remedial investigation (RI) as recommended by ADEM by installing monitoring wells. EPA sampled the soil taken from holes bored to construct wells. The soil and groundwater samples, taken in 2000, were analyzed and evaluated for data quality. EPA sampling data detected PCE and TCE. During Phase II of the RI during January 2001, additional monitoring wells were dug and sampled. In Phase III of the RI during February 2002, two permanent monitoring wells and three temporary wells were installed. These five wells and other industrial wells were sampled (8). Contaminants found during the February 2002 sampling round are listed in Appendix A.
On the basis of a review of documentation ADEM provided under the provisions of CERCLA, EPA proposed to list the CCP site on the NPL. The proposal was published in the Federal Register on May 11, 2000. The NPL is an EPA list of the most serious, uncontrolled or abandoned, hazardous-waste sites that are identified for possible long-term remedial response. EPA may use money from a special trust fund (also called Superfund) to conduct these remedial responses (42USC9628).
For more information, public documents for the CCP site are available for review at:
Montgomery Library Main Branch
245 High Street
Montgomery, AL. 36104
Demographics, Land Use, and Natural Resources Use
The CCP site is located in a downtown business, governmental, and industrial area of Montgomery, Montgomery County, Alabama. The population is predominately workers who commute from at least six counties into downtown Montgomery. Based on the numbers of workers in selected buildings, ADPH estimated the number of workers to be between 10,000 and 20,000. Workers are employed by a variety of private, public, and governmental institutions. Workers vary widely with respect to race, income, and education levels. ADPH assumes worker ages range from 18 to 65 years of age. Local residents make up a smaller portion of the population. Based on the number of homes and apartments, ADPH estimated the number of residents to be approximately 1,675. Residents also vary widely with respect to age, race, income, and education levels. Children at the CCP site include resident children and approximately 200 who commute into attend day care centers (6).
Much of the area is covered by paved city streets and parking lots; stone- or concrete-covered sidewalks; and public, private, and government buildings. Spaces that lack hard surfaces include
Well-landscaped, grass-covered parks, residential yards that vary with regard to vegetative cover, partially vegetated vacant lots, industrial property, and railroad tracks (6).
MWWSSB reports active customers in the area, but it is not aware of anyone using groundwater from domestic wells. ADPH Bureau of Clinical Laboratories does not receive samples for bacteriological analysis from addresses in the area. No on-site well survey has been conducted because no evidence exists to justify such a survey.
Municipal water has been available to the area since 1885. MWWSSB operates a blended-water system that takes water from the Tallapoosa River, the West Well Field, and the North Well Field (NWF). The Wellhead Protection Plan, dated April 1997, reports that in 1990, approximately 5 percent of the MWWSSB total water supply came from the NWF. Raw water from the NWF is pumped to the Court Street Pump Station for storage and treatment. The water is treated as needed with fluoride and chlorine. After treatment, the water is pumped into the water system for delivery to customers (4). MWWSSB serves 220,002 people. MWWSSB provides 40 percent of the water supply of the Pintlala Water and Fire Protection Authority, which serves 3,819 people. MWWSSB also provides 75 percent of the water supply of the Hunter Walk Manufactured Home Community that serves 597 people (2).
Five of the 15 wells in the NWF range in depth from 70 feet to 79 feet bgs, and draw water from the shallow aquifer (Wells 2, 9 W, 9 E, 18, and 20). One of the 15 wells in the NWF is 270 feet deep, and it only draws water from the Gordo Formation (Well 11). Eight of the 15 wells in the NWF range from 600 feet to 755 feet bgs. Two of those wells draw water from the Gordo Formation (Wells 7 and 14). All eight of those wells draw water from the Coker Foundation (Wells 5, 7, 8, 13, 14, 51, 52, and 53) (4).
A prominent natural resource, the Alabama River, is located at the northwestern portion of the CCP site. The river is classified as a fish and wildlife area and a water contact sport area (2). Development along the riverfront has created tourist and recreation attractions, including a minor league baseball stadium, an amphitheatre, a marina, a park with a public boat landing, riverboat rides, and a renovated train station. The Montgomery Civic Center is adjacent to the south side of the park. Business, real estate, and government professionals are planning further downtown and riverfront development. Other downtown tourist attractions include Old Alabama Town, the Civil Rights Museum, the Dexter Avenue King Memorial Baptist Church, the Rosa Parks Museum, and the Hank Williams Museum. Combined, these facilities attract millions of visitors annually (3, 6).
ADPH and ATSDR Involvement
ADPH, under a cooperative agreement with ATSDR, attended public meetings held by EPA and the City of Montgomery. ADPH reviewed existing data and conducted a site visit with EPA in May 2000, as well as several subsequent site visits to collect information about the community. ADPH announced the public health assessment activity; solicited community involvement through mailings, the Internet, and interviews. ADPH provided further information about the public health assessment process on the Internet. ATSDR provided technical assistance and toxicological resources to ADPH throughout the process.
Quality Assurance and Quality Control
The quality of this public health assessment is dependent upon the quality and quantity of the sampling data and information evaluated. ADEM, EPA, and MWWSSB produced sampling data for this evaluation. ADPH reviewed available information on the chain of custody, laboratory QA/QC, and data-reporting procedures provided in documents referenced in this report. ADPH also reviewed field notes, maps, diagrams, photographs, and site descriptions for assistance in interpreting sampling data. Environmental sampling was conducted by EPA-certified laboratories, using approved methods; therefore, ADPH found the data quality to be acceptable.
Environmental Contamination and Exposure
Several investigations and sampling events have been conducted at the CCP site since 1993. Sampling data are reported in documents referenced in this report. ADPH screened the substances reported in sampling data to select those that require a public health evaluation. Each substance was screened by comparing its concentration level in the environment with ATSDR health-based comparison values.
Comparison values are set below the levels that would be expected to harm public health to assure a margin of safety to the public. ADPH emphasizes that comparison values are screening tools for health assessments, and are not to be confused with clean-up levels, health-effect levels, or toxicity levels.
Substances at the CCP site that were found at levels above comparison values are called the contaminants of concern, which are the subject of public health assessment. Substances for which no comparison values have been established are automatically assigned contaminant of concern status.
When a substance is released into the environment, it enters the air, soil, water, or food chain. That release does not always cause human exposure. People are exposed only if they come into contact with the substance. Exposure may occur through breathing, eating or drinking, or skin contact. Many things determine whether exposure will result in adverse health effects:
- exposure dose (how much),
- exposure duration (how long),
- exposure frequency (how often),
- how contact occurred,
- exposure to other substances,
- age, sex, and family traits,
- health habits, and
- health status.
In this document, ADPH evaluated PCE and TCE groundwater-sampling data produced by MWWSSB, ADEM, and EPA. Water results are reported in parts per billion (ppb)
In 1991 and 1992, MWWSSB detected PCE levels in Wells 9W and 9E ranging from non-detectable to 21.0 ppb. Well 9W was taken out of service in 1992. Since that time, sampling of Well 9W detected levels ranging from non-detectable to 58.1 ppb (7). Well 9E remained on standby until 1997, when it was closed due to contamination and structural problems. The PCE level in well 9E at that time was 4.23 ppb.
In 2000, EPA sampling of shallow and deep aquifers in their area of investigation detected PCE levels ranging from non-detectable to 85.0 ppb. Their sampling detected TCE levels ranging from non-detectable to 18.0 ppb (8).
EPA field activities for this site's Remedial Investigation include the collection of subsurface soil and groundwater samples in three phases. A total o16 permanent and 16 temporary monitoring wells were installed during the three phases of the RI. Analytical results for groundwater samples collected during the RI indicate that the upper aquifer at the CCP site has been affected by past waste disposal practices in the downtown Montgomery area. Several compounds were detected at elevated concentrations when compared to the Federal Drinking Water Maximum Contaminant Levels (MCL). PCE was the organic contaminant detected at elevated concentrations in the most wells. The 2002 sampling of shallow and deep aquifers by EPA detected PCE levels ranging from 1.0 ppb to 240 ppb (8).
Very little soil contamination is present in the Capitol City Plume site area. Except for benzo(a)pyrene in one sample, no organic contamination was detected at elevated levels. Inorganic contaminants were detected in some samples; however, the levels were low (Table 1).
In 1993 and 1994, ADEM conducted sampling of subsurface (from 4 to 34 ft.) soil in the vicinity of the RSA Energy Plant detected PCE levels ranging from non-detectable to 7843.0 parts per million (ppm) (2). Soil removal was accomplished at this site.
In 2000, EPA sampling of subsurface soil in its area of investigation detected PCE levels ranging from non-detectable to 2.0 ppm. Their sampling detected TCE levels ranging from non-detectable to 9.0 ppm (8).
EPA conducted additional sampling in 2002. Neither PCE nor TCE were reported in the analysis of the subsurface-soil samples. RI sampling results do not provide strong evidence that contaminated soil is a significant source of groundwater contamination (8).
ADPH analyzed multiple exposure-pathway scenarios to groundwater and subsurface soil. Exposure pathway descriptions for residents and workers are based on past events, information in public documents, and information from the community. Exposure pathway scenarios are described below.
PCE and TCE were discovered during excavation of the RSA Energy Plant in 1993 (2). A completed exposure pathway to PCE and TCE existed in the past for excavation workers. A potential future exposure pathway to PCE and TCE exists for excavation workers in further development of the downtown area.
An industrial well on North Court Street has been in use for approximately 35 years. The well draws water from the shallow aquifer and is used daily in a vehicle (bus) washing operation (4). A potential past exposure pathway to PCE and TCE exists for washing-operation workers. Testing of this well in 2002 did not show any contamination from PCE or TCE.
A second industrial well (an irrigation well used to water grass) in downtown Montgomery was also tested in 2002. The presence of PCE was noted, but at a level below the Maximum Contaminant Level (MCL).
Well 9W was taken out of service in 1992 after PCE was detected at levels above the MCL. The well draws water from the shallow aquifer (2, 7). A potential past exposure pathway to PCE existed for customers if contaminated water was distributed.
Improperly constructed or improperly abandoned wells that extend through clay layers into the Gordo Formation and the Coker Formation exist in the NWF area. Potentially, contaminants could move downward through these openings in the clay layers into the lower aquifers, contaminating active MWWSSB wells in the NWF (4). A potential future exposure pathway to PCE and TCE exists to MWWSSB customers if contaminated water is distributed.
Many single-family residences in the area are at least 60 years old, and most residents are of low socioeconomic status (6). A Potential Past Exposure Pathway to PCE and TCE exists for households that have used groundwater from domestic wells. No domestic wells are currently in use in the downtown Montgomery area.
No completed pathway for subsurface soils in the downtown Montgomery area has been identified. It is unlikely that children will be digging in this area. Limited exposure for adults during construction activities could occur.
Many of the metals detected in groundwater-monitoring wells are essential nutrients and are at levels that should not cause any adverse health effects because of dilution in the blended-water system.
Contaminants of concern at this site were selected from those chemicals found at concentrations that exceeded a health-based comparison value in at least one environmental medium (e.g., air, water, soil). Lifetime (70 years) exposure to chemical concentrations at or below the appropriate comparison values for a chemical would not result in any significant risk for cancer or non-cancer health effects. Comparison values used in this assessment include the following:
- ATSDR Environmental Media Evaluation Guides (EMEGs)
- ATSDR Cancer Risk Evaluation Guides (CREGs)
- Reference Dose Media Evaluation Guides (RMEGs), computed from EPA
- Reference Dose (RfD) for chronic exposure of a child, assuming pica behavior for soil ingestion
- EPA Drinking Water Health Advisories-Lifetime (LTHA)
- EPA Safe Drinking Water Act Maximum Contaminant Levels (MCL)
Typically, the toxicological evaluation in a public health assessment is a comparison of the estimated exposure dose (i.e., the amount of a substance to which individuals in an exposure pathway are exposed daily) with an appropriate health guideline. The guideline is usually either the ATSDR Minimal Risk Level (MRL), the EPA Reference Dose (RfD), or the U.S. Food and Drug Administration (FDA) Acceptable Daily Intake (ADI). The MRLs and RfDs are estimates of daily human exposure to a contaminant below which noncarcinogenic adverse health effects are unlikely to occur. Therefore, a review of the toxicological literature is conducted to determine whether the specific exposure situation represents a hazard to public health.
Chemicals of Concern:
Many of these substances may have been used or stored over several decades at a variety of the businesses operating in downtown Montgomery (1, 2). The types of businesses could include, for example, dry cleaners, service stations, auto repair shops, printers. Although numerous possible sources exist, EPA did not locate any other sources of contamination other than the one found at the RSA Energy Power Plant in downtown Montgomery.
a. TetrachloroethyleneTetrachloroethylene is a manufactured nonflammable liquid solvent that is widely used in dry cleaning, wood processing, fabric manufacturing, and metal degreasing. It readily evaporates into the air and has a sharp, sweet odor. Other names for tetrachloroethylene include PCE, "perc," perchloroethylene, and tetrachloroethene (9).
People are exposed to PCE most often when they use it in their work, when cleaning, or when engaged in hobbies. Clothes that have been dry cleaned also will release PCE into the air. You also can be exposed through contaminated drinking water. Small amounts of PCE can pass through the skin when people handle the chemical, contaminated soil, or bathe in contaminated water. High levels of PCE (particularly in closed, poorly ventilated areas) can cause dizziness, headache, sleepiness, confusion, nausea, difficulty in speaking and walking, unconsciousness, and death. People at this site are not expected to be exposed to levels that could cause these symptoms.
Results from some studies suggest that women, who work in dry cleaning industries, where exposures to PCE can be quite high, may have more menstrual problems and spontaneous abortions than women who are not exposed. However, it is not known whether PCE was responsible for these problems because other possible causes were not considered. The health effects of breathing in air or drinking water with low levels of PCE are not known. The U.S. Department of Health and Human Services (DHHS) had determined that PCE may reasonably be anticipated to be a carcinogen.
Contaminated wells at this site were capped when PCE was detected. The contaminated wells are not in use, and ADPH has determined that the site does not pose a current public health hazard.
b. LeadExposure to lead can cause adverse health effects, especially for young children and pregnant women, or women of childbearing age. Lead uptake by pregnant women or women of childbearing age can move through the placenta and into the developing fetus. Lead is a neurotoxin that permanently interrupts normal brain development. Lead is known to accumulate in the body and has no beneficial biological function. ATSDR has not developed a health guideline for lead because no safe threshold has been identified. FDA published a provisional, tolerable daily lead-intake value of 6 micrograms (µg) for a 10-kilogram (kg) child, based on an acceptable blood lead level of 10 micrograms per deciliter (µg/L). A survey of a variety of foods determined the average adult lead intake to be 54 micrograms per day (µg/day) (10).
The Centers for Disease Control and Prevention (CDC) considers lead poisoning the number one preventable pediatric health problem facing children today. Several signs of lead toxicity have been described at low levels of exposure. Symptoms include decreased attention span, hyperactivity, and lower IQ scores. Lead levels as low as 10 micrograms/deciliter (µg/dL) have been shown to affect child development. Several studies provide sufficient evidence that children's cognition is adversely affected by lead (10).
Lead is a cumulative poison, in that many small doses have the same effect as a single large dose. Lead primarily attacks the nervous system. Lead also interferes with growth and development of the nervous system. Some laboratory animals that were fed a diet containing lead developed cancers of the liver or kidneys. EPA has classified lead as a probable human carcinogen (EPA Class B2). Insufficient information is available to evaluate the risk of contracting cancer from exposure to lead (10).
No health guidelines have been developed for exposure to lead in soil, so the exposure doses for lead in this medium cannot be evaluated directly. Only one in 66 soil samples at this site demonstrated the presence of lead at a level of 2500 mg/kg. EPA allows 1000 mg/kg of lead at remedial site. Downtown Montgomery is primarily a commercial site. Exposure to lead in subsurface soil at this site is highly unlikely.
Lead also was detected in monitoring wells at the CCP site. Should water from the municipal wells in the area contain lead, it would be diluted due to the blending of water in the water system.
c. ChromiumChromium in the environment occurs primarily in the trivalent state (III), which is the most stable form, or in the hexavalent state (VI), which is a strong oxidizing agent. Trivalent chromium is thought to be an essential nutrient required for sugar and fat metabolism. Normal dietary intake of chromium for humans is believed to be suboptimal. The estimated safe and adequate daily dietary intake for trivalent chromium is 50 to 200 µg. However, trivalent chromium has a very large safety range, and no documented signs of chromium toxicity at levels up to 1 milligram (1000 µg) per day have appeared in any of the nutritional studies. Most diets are thought to contain less than 60% of the minimum suggested daily intake of 50 µg. As a nutrient, chromium will be of benefit only to those who are marginally or overtly chromium deficient (11).
Hexavalent chromium is recognized by the International Agency for Research on Cancer (IARC) and by DHHS as a carcinogen. The increased risk of cancer occurs through inhalation and affects primarily the lung. Although individual studies suggest the possibility of an excess incidence of cancer at sites outside the lung, the results from these studies are inconsistent. Further, studies have shown that the available evidence strongly indicates that hexavalent chromium is changed (reduced) in body fluids and tissues to the trivalent form, which reduces its potential toxicity and genotoxicity. Animal studies have not shown trivalent chromium to be carcinogenic by ingestion. Therefore, even in the respiratory tract, which is the only consistent target of hexavalent chromium carcinogenicity in humans, barriers exist to hamper chromium carcinogenicity.
One in 66 soil samples showed the presence of chromium at this site. Fifty-six of 66 shallow and intermediate groundwater samples showed chromium present. Exposure to chromium in the subsurface soil and groundwater at this site is unlikely. Excavation activities in downtown Montgomery could expose workers to contaminants in the soil. This exposure however would be minimal and should pose no health hazards.
d. ArsenicArsenic is a naturally occurring element widely distributed in the earth's crust. In the environment, arsenic is combined with oxygen, chlorine, and sulfur to form inorganic arsenic compounds. Arsenic in animals and plants combines with carbon and hydrogen to form organic arsenic compounds (12).
Inorganic arsenic compounds are mainly used to preserve wood. Organic arsenic compounds are used as pesticides, primarily on cotton plants.
Breathing high levels of inorganic arsenic can give one a sore throat or irritated lungs. Ingesting high levels of inorganic arsenic can result in death. Lower levels of arsenic can cause nausea and vomiting, decreased production of red and white blood cells, abnormal heart rhythm, damage to blood vessels, and a sensation of "pins and needles" in hands and feet.
Ingesting or breathing low levels of inorganic arsenic for a long time period can cause a darkening of the skin and the appearance of small "corns" or "warts" on the palms, soles, and torso (12).
Several studies have shown that inorganic arsenic can increase the risk of lung, skin, bladder, liver, kidney, and prostate cancers. The World Health Organization (WHO), DHHS, and EPA have determined that inorganic arsenic is a human carcinogen (12).
It is not known whether exposure to arsenic will result in birth defects or other developmental effects in humans. Birth defects have been observed in animals exposed to inorganic arsenic.
It is likely that adverse health effects seen in children exposed to high amounts of arsenic will be similar to the effects seen in adults.
Exposure to arsenic in the subsurface soil and groundwater at this site is unlikely. Excavation activities in downtown Montgomery could expose workers to contaminants in the soil; however, this exposure would be minimal and should pose no health hazards.
e. AntimonyAntimony is a silvery-white metal that is found in the earth's crust. Antimony ores are mined and then mixed with other metals to form antimony alloys or combined with oxygen to form antimony oxide (13).
Little antimony is currently mined in the United States. It is brought into this country from other countries for processing. However, companies in the United States do produce antimony as a by-product of smelting lead and other metals.
Antimony is not used alone because it breaks easily, but when mixed into alloys, it is used in lead storage batteries, solder, sheet and pipe metal, bearings, castings, and pewter. Antimony oxide is added to textiles and plastics to prevent them from catching fire. It is also used in paints, ceramics, and fireworks, and as enamels for plastics, metal, and glass.
Exposure to antimony at high levels can result in a variety of adverse health effects. Breathing high levels for a long time can irritate the eyes and lungs and can cause heart and lung problems, stomach pain, diarrhea, vomiting, and stomach ulcers. In short-term studies, animals that breathed very high levels of antimony died. Animals that breathed high levels had lung, heart, liver, and kidney damage. In long-term studies, animals that breathed very low levels of antimony had eye irritation, hair loss, lung damage, and heart problems. Problems with fertility also were noted. In animal studies, problems with fertility have been seen when rats breathed very high levels of antimony for a few months.
Ingesting large doses of antimony can cause vomiting. Any other effects that may be caused by antimony ingestion are unknown. Long-term animal studies have reported liver damage and blood changes when animals ingested antimony. Antimony can irritate the skin if left on it.
Antimony can have beneficial effects when used for medical reasons. It has been used as a medicine to treat people infected with parasites.
The DHHS, IARC, and EPA have not classified antimony as to its human carcinogenicity (13).
Exposure to antimony at this site from groundwater is unlikely. If antimony should enter the water supply, it would be diluted due to blending.
f. BerylliumBeryllium is a hard, grayish metal naturally found in mineral rocks, coal, soil, and volcanic dust. Beryllium compounds are commercially mined, and the beryllium is purified for use in nuclear weapons and reactors, aircraft and space vehicle structures, instruments, x-ray machines, and mirrors. Beryllium ores are used to make specialty ceramics for electrical and high-technology applications. Beryllium alloys are used in automobiles, computers, sports equipment (golf clubs and bicycle frames), and dental bridges (14).
Swallowing beryllium has not been reported to cause effects in humans because very little beryllium is absorbed from the stomach and intestines. Ulcers have been seen in dogs ingesting beryllium in the diet. Beryllium contact with skin that has been scraped or cut may cause rashes or ulcers.
DHHS and the IARC have determined that beryllium is a human carcinogen. EPA has determined that beryllium is a probable human carcinogen (14).
The level of beryllium found in the monitoring well, while above comparison values, was extremely low. Should beryllium enter the public water supply, it should not pose a health risk.
g. CobaltCobalt is a naturally occurring element found in rocks, soil, water, plants, and animals. There are non-radioactive and radioactive forms of cobalt (15).
Non-radioactive cobalt, referred to as stable cobalt, is used to produce alloys (mixtures of metals) used in the manufacture of aircraft engines, magnets, grinding and cutting tools, artificial hip and knee joints. Cobalt compounds are also used to color glass, ceramics, and paints, and used as a drier for porcelain enamel and paints.
Cobalt has both beneficial and harmful effects on human health. Cobalt is beneficial for humans because it is part of vitamin B12.
Exposure to high levels of cobalt can result in lung and heart effects and dermatitis. Liver and kidney effects have also been observed in animals exposed to high levels of cobalt.
Exposure to large amounts of radioactive cobalt or the radiation it emits can damage cells in your body from the radiation. You might also experience acute radiation syndrome which includes nausea, vomiting, diarrhea, bleeding, coma, and even death
Non radioactive cobalt has not been found to cause cancer in humans or animals following exposure in food or water. Cancer has been shown, however, in animals who breathed cobalt or when cobalt was placed directly into the muscle or under the skin. Based on the laboratory animal data, IARC has determined that cobalt and cobalt compounds are possibly carcinogenic to humans.
Exposure to high levels of cobalt radiation can cause changes in the genetic materials within cells and may result in the development of some types of cancer (15).
Exposure to cobalt at this site from groundwater is unlikely. If antimony should enter the water supply, it would be diluted due to blending.
h. CopperCopper occurs naturally at levels of approximately 50 ppm in the earth's crust. Levels at the CCP site vary up to 480 ppm in subsurface soil. Groundwater in the plume has levels up to 1600 ppb (16).
Potential for high exposure of the general population to copper may exist where people consume large amounts of tap water that has picked up copper from the distribution system. People living near copper smelters and refineries, and workers in these and other industries, may be exposed to high levels of copper in dust by inhalation and ingestion.
Copper levels were elevated in the soil at the CCP site, but no health guideline has been developed for copper. Estimates for exposure to copper in food range from 1-5 mg/day. Daily contact with copper in soil would result in exposures much less than those from copper commonly found in food, so adverse health effects are unlikely (16). Infrequent exposure to the soil on the site would make development of adverse health effects unlikely.
Copper was not detected in the public water supply wells above comparison values.
i. Di(2-ethylhexyl)phthalateDi(2-ethylhexyl)phthalate (DEHP) is a manufactured chemical that is commonly added to plastics to make them flexible. DEHP is a colorless liquid with almost no odor (17).
DEHP is present in plastic products such as wall coverings, tablecloths, floor tiles, furniture upholstery, shower curtains, garden hoses, swimming pool liners, rainwear, baby pants, dolls, some toys, shoes, automobile upholstery and tops, packaging film and sheets, sheathing for wire and cable, medical tubing, and blood storage bags.
At the levels found in the environment, DEHP is not expected to cause harmful health effects in humans. Most of what we know about the health effects of DEHP comes from studies of rats and mice given high amounts of DEHP.
Harmful effects in animals generally occurred only with high amounts of DEHP or with prolonged exposures. Moreover, absorption and breakdown of DEHP in humans is different than in rats or mice, so the effects seen in rats and mice may not occur in humans.
Skin contact with products containing DEHP will probably cause no harmful effects because it cannot be taken up easily through the skin
DHHS has determined that DEHP may reasonably be anticipated to be a human carcinogen. The EPA has determined that DEHP is a probable human carcinogen. These determinations were based entirely on liver cancer in rats and mice. The IARC has stated that DEHP cannot be classified as to its carcinogenicity to humans (17).
The presence of DEHP in a monitoring well at the CCP does not pose a public health hazard.
j. ManganeseThe manganese concentration in the shallow groundwater-monitoring wells was higher than that in the drinking water in towns in Greece, in which elderly (average age 67 years), long-term residents (residence of 50 years or longer) displayed differences in various neurological signs from similarly-aged residents of a nearby town in which the water contained much less manganese. A child subject to pica behavior might ingest more manganese each day, weight for weight, from the soil on the property than did the villagers described above. No evidence has been found to connect manganese ingestion with cancer. Pica behavior typically does not last as long as the people in the Greek towns drank manganese-contaminated water, and a child of the age subject to pica behavior is not likely to be exposed to soil at this site. Manganese also is less readily absorbed from food or other solid material than from water (18-19).
Exposure to metals at levels of health concern at the CCP site is not likely.
k. NickelThe most common harmful health effect of nickel in humans is an allergic reaction. Approximately 10-15% of the population is sensitive to nickel. People can become sensitive to nickel when jewelry or other objects containing nickel are in direct contact with the skin. Once a person is sensitized to nickel, further contact with the metal will produce a reaction. The most common reaction is a skin rash at the site of contact. The skin rash also may occur at a site on the body other than the site of contact. Less frequently, some people who are sensitive to nickel have asthma attacks following exposure to nickel. Some sensitized people react when they ingest nickel in food or water or breathe dust containing nickel (20).
DHHS has determined that nickel metal may reasonably be anticipated to be a carcinogen and that nickel compounds are known human carcinogens. IARC has determined that some nickel compounds are carcinogenic to humans and that metallic nickel may possibly be carcinogenic to humans. EPA has determined that nickel-refinery dust and nickel sulfide are human carcinogens (20).
Exposure to nickel at this site from either groundwater or subsurface soil is unlikely. Nickel was not detected in the public water supply wells.
Public Health Implications
Excavation workers at the RSA Energy Plant construction site in 1993 experienced an acute exposure to PCE and TCE in groundwater and subsurface soil. ADPH assumes that approximately 15 workers might have been involved in the excavation at the plant. The routes of exposure may have included inhalation, incidental ingestion, and dermal absorption. Inhalation would result when PCE and TCE, which are volatile organic compounds (VOCs), evaporate in the presence of air. Incidental ingestion would result from normal hand-to-mouth activities, like wiping the face or eating, drinking, or smoking with unwashed hands. Dermal absorption would result from contaminated groundwater or soil remaining on the skin throughout the work day. However, these exposures were not long-lived. No data are available to quantify individual employee's exposures during the removal and transport of contaminated soils. Based on the short exposure durations and the localized concentrations of contaminants, health risks during excavation likely were minimal.
Excavation workers employed at future construction sites in downtown Montgomery could potentially experience acute exposure to PCE and TCE in groundwater and subsurface soil. The number of workers exposed would depend upon the nature of the activity; therefore, no estimate of the number of people potentially exposed through this pathway is offered.
Workers using shallow groundwater for vehicle washing operations could potentially experience chronic (long-term) exposure to PCE and TCE. Several individuals have conducted washing activities daily for approximately 20 years. Others have been involved fewer than 15 years. The routes of exposure could include inhalation and dermal absorption. The 2002 well-sampling data do not show the presence of PCE or TCE above the health comparison value.
Because no MWWSSB wells are known to be currently affected by the CCP site, no current exposure to site contaminants is occurring. Customers of municipal water supplies from the MWWSSB blended-water system potentially could have experienced a past exposure to PCE from Well 9W. The routes of exposure could include ingestion, inhalation, and dermal absorption. However, because this is a blended water system with multiple wells, the concentration to which consumers would be exposed is likely to be greatly diluted. In addition, less than 5 percent of the total water volume of the Montgomery water supply generally is expected to come from the NWF in which Well 9W is located.
In the future, customers of the municipal water supply could potentially experience chronic exposure to PCE, TCE, and other VOCs if contaminants move downward into the deeper aquifer and affect the deep wells of the NWF. Approximately 224,420 customers receive water either directly from MWWSSB, from the Pintlala Water and Fire Protection Authority, or the Hunter Walk Manufactured Home Community. The future routes of exposure could include ingestion, inhalation, and dermal absorption. Ingestion would result from drinking and cooking with the water. Inhalation would result when PCE, TCE, or VOCs evaporate from shower spray or water left standing uncovered. Dermal absorption would result from bathing, showering, and washing activities. If the contaminant plume is left unchecked, customers could be exposed to PCE, TCE, and other VOCs in the future. However MWWSSB regularly tests all water to assure that contaminant levels are not above state or Federal Safe Water Standards.
If any households in the past used domestic wells from the shallow aquifer, people potentially could have experienced chronic exposure to PCE, TCE, and VOCs. ADPH has no information about the past existence of domestic wells. If wells were in use, the number of people exposed would have been limited to those living in particular households. No estimate of the number of people potentially exposed through this pathway is offered. No wells are currently in use and, therefore, no exposure is occurring.
ADPH considered the possibility that structures (either residential or commercial) contain a basement and are located in the area of the contaminated groundwater plume. Under this scenario, the potential exists for exposure to TCE or PCE via inhalation of vapors that migrate into basement air through the floor and walls. However, EPA has determined that the contaminated water is 50 feet bgs and that vapor intrusion is unlikely due to the depth of contaminated groundwater. It is doubtful that any adverse health effects have or will occur to people that have inhaled or are inhaling the chemicals found in the basement air of their residences.