PUBLIC HEALTH ASSESSMENT
CLEBURN STREET WELL SITE
GRAND ISLAND, HALL COUNTY, NEBRASKA
ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS
This section of the public health assessment identifies contaminants of concern found in specific environmental media at the Cleburn Street Well site. The contaminants of concern will be evaluated later in the health assessment to determine if exposure to them will affect the public's health.
ATSDR selects and discusses contaminants of concern using the following information:
It is emphasized that the listing of a contaminant in the following tables does not mean that it will cause adverse health effects if people are exposed at the reported concentrations. Rather, the listing of a contaminant indicates that the contaminant will be evaluated further in this public health assessment. When a contaminant is selected as a contaminant of concern in one medium, its presence or absence in all media sampled will be discussed.
The data tables presented in this section include the following abbreviations and/or acronyms:
| = | Cancer Risk Evaluation Guide | |
| = | Environmental Media Evaluation Guide | |
| = | Reference Dose Media Evaluation Guide | |
| = | Lifetime Health Advisory | |
| = | Maximum Contaminant Level Goal | |
| = | Maximum Contaminant Level | |
| = | Proposed Maximum Contaminant Level Goal | |
| Data Clarifiers | ||
| = | parts per billion | |
| = | not detected | |
| = | associated numerical value is an estimated quantity | |
| = | compound was qualitatively identified; however, numerical value is less than the contract-required quantitation limit or less than the EPA limit of quantitation and, therefore, is an estimated value | |
EMEGs are media-specific values developed by ATSDR for use in selecting environmental contaminants of potential health concern. EMEGs are calculated using noncancer health endpoints and do not consider potential carcinogenic effects. RMEGs are media-specific values developed by ATSDR from EPA Reference Doses (RfDs). RfDs are EPA's estimates of the daily exposure to a contaminant that is unlikely to cause adverse health effects. CREGs are estimated contaminant concentrations expected to cause no more than one excess cancer in a million persons exposed over a lifetime (70 years). Maximum Contaminant Level Goals (MCLGs) are EPA-developed drinking water health goals. EPA believes that MCLGs represent levels that no known or anticipated adverse effect on the health of persons should occur which allows an adequate margin of safety. Proposed Maximum Contaminant Level Goals (PMCLGs) are MCLGs that are being proposed. Maximum Contaminant Levels (MCLs) represent contaminant concentrations that EPA deems protective of public health (considering the availability and economics of water treatment technology) over a lifetime (70 years) at an exposure rate of 2 liters of water per day. EPA's Lifetime Health Advisories (LTHAs) represent the level of a contaminant in drinking water (with a margin of safety) at which adverse noncarcinogenic health effects would not be anticipated during a lifetime (70 years) exposure. While MCLs are regulatory concentrations, PMCLGs, MCLGs, and LTHAs are not.
As previously discussed, sampling data have been collected from various environmental media at the Cleburn Street well site, primarily during the 1988 Site Investigation and the 1992-1993 Remedial Investigation. Relevant contaminant data from these and other sampling events, which were described earlier in the Background section, are discussed and evaluated below.
Available sampling data show that VOCs have been released from multiple sources to groundwater in the vicinity of the Cleburn Street well. VOCs, primarily PCE, have been detected in soils, soil gas, groundwater monitoring wells, municipal water supply wells, and/or water supply reservoirs at the site.
For the purpose of this public health assessment, "on-site" refers to those areas within the general site boundary shown in Figure 1. This includes the Cleburn Street, Pine Street, and Lincoln Street wells, the Pine Street reservoir, and the following potential contamination sources: the former One Hour Martinizing cleaners, Ideal Cleaners, Liberty Cleaners, former Oil Dealers Association, and former Nebraska Solvents Company.
It should be noted that the sampling data evaluated by ATSDR do not include information about inorganic compounds or semi-volatile organic compounds. However, other information reviewed by ATSDR indicates that the groundwater contamination at the site is limited to VOCs only. Therefore, inorganic and semi-volatile organic compounds will not be discussed further in this assessment.
Soil Gas
In March 1988, a soil gas investigation was conducted in the Cleburn Street well area to estimate the extent of PCE groundwater contamination and identify potential source areas. Samples were taken at a depth of about 5 feet below ground service at more than 70 locations and analyzed in the field for PCE (12). The sampling results indicated four areas with significant PCE soil gas levels - One Hour Martinizing, former Nebraska Solvents Company, Liberty Cleaners, and Ideal Cleaners (see Figure 3). The highest PCE soil gas concentration (1,560,000 ppb) was found on the east side of the One Hour Martinizing dry cleaners building. Maximum soil gas levels at the other three areas were as follows: 94,800 ppb at the former Nebraska Solvents Company; 59,000 ppb at Liberty Cleaners; and 36,800 ppb at Ideal Cleaners. Based on the high PCE soil gas concentrations, these four areas were identified as potential sources of VOC groundwater contamination (1,12).
Trace amounts of PCE were found in soil gas samples at four other areas - former Oil Dealers Association, Vintage Body Shop, Sink and Baer Cleaners, and Peavey Company. (PCE was not detected at the Grand Island Oil Company.) Since it is reported that these businesses never used PCE, the positive soil gas values were likely due to groundwater contamination associated with the four potential source areas previously discussed (1,12).
Soil
During Phase I of the RI, which was conducted in May and June 1992, soil samples were collected from 19 soil borings at eight areas based on the results of the 1988 soil gas investigation. The Phase I soil boring locations are shown in Figure 4. Samples were collected from the 0-1 foot and the 4-5 foot depth intervals in the shallow borings, and the 6-8 foot and the 12-14 foot depth interval in the deep borings. Soil samples were also collected from borings used in the installation of the 11 Phase I monitoring wells (Figure 5). Depth discrete soil samples for the shallow monitoring well borings were collected from depths of 0-1 foot and 4-5 feet, while samples for the deep monitoring well borings were collected at various depth intervals ranging from 0-1.5 feet to 25.0-26.5 feet. All Phase I soil samples were analyzed for VOCs (1).
During Phase III of the RI (June 1993), an additional 53 soil samples were collected from 17 soil probe locations at the One Hour Martinizing source area (Figure 6) and analyzed in the field for PCE and trichloroethylene (TCE). Thirteen (13) of the soil probe locations were vertical profile borings, collected at depth intervals of 1-3, 6-8, 12-14, and 18-20 feet, with the remaining 4 boring locations angled under the building to a depth of 8.5 to 10.5 feet below the building slab (7).
Analysis of the RI soil samples (Table 1) indicated the presence of VOCs, primarily PCE, at the four potential source areas previously identified - One Hour Martinizing, Liberty Cleaners, Ideal Cleaners, and former Nebraska Solvents Company. In general, soil contamination was greatest at the One Hour Martinizing location.
PCE was found in samples from all four potential source areas at levels ranging from a minimum of 6.5 ppb at Ideal Cleaners to a maximum of 11,000,000 ppb in a soil sample from a depth interval of 25 to 26 feet at One Hour Martinizing. Significant levels of PCE (2,800 ppb) were also found in shallow (0 to 1 foot deep) soil samples underneath a concrete and/or asphalt parking area at One Hour Martinizing.
TCE was found in soil samples at Nebraska Solvents Company and One Hour Martinizing at a maximum concentration of 16 ppb and 4,400 ppb, respectively. The highest TCE level was detected at a depth of 25 to 26 feet at One Hour Martinizing.
Other VOCs, specifically 1,1-Dichloroethylene (1,1-DCE), 1,1,1-Trichloroethane (1,1,1-TCA), and 1,1,2-Trichloroethane (1,1,2-TCA), were also found at the One Hour Martinizing location with the greatest concentrations occurring at the 25-26 foot depth interval. 1,2-Dichloroethylene (1,2-DCE) was found at both One Hour Martinizing and Nebraska Solvents at 48 ppb and 83 ppb, respectively.
It should be noted that the contaminant levels in site soils were all below ATSDR comparison values except for PCE in deep subsurface soils at the One Hour Martinizing location.
No VOCs were detected in soil samples from the other four areas investigated (Grand Island Oil
Company, Vintage Body Shop, Sink & Bear Cleaners, and former Oil Dealers Association).
Table 1. Contaminant Concentrations in Soil (various depths)1
| Contaminant | Concentration Range (ppb) | Comparison Value | ||||
| Liberty Cleaners2 | 1-Hr Martinizing3 | NE Solvents2 | Ideal Cleaners2 | ppb | Source | |
| 1,1-Dichloroethylene | ND | 780 | ND | ND | 1,000 | CREG |
| 1,2-Dichloroethylene | ND | 48 | 83 | ND | 40,000 (trans-) | RMEG |
| Tetrachloroethylene (PCE) | 13 - 110 | 8 - 11,000,000J | 16 - 810 | 6.5 - 270 | 10,000 | CREG |
| 1,1,1-Trichloroethane | ND | 3,100 | ND | ND | None | |
| 1,1,2-Trichloroethane | ND | 33 | ND | ND | 10,000 | CREG |
| Trichloroethylene (TCE) | ND | 50 - 4,400 | 16 | ND | 60,000 | CREG |
Groundwater -- Monitoring Wells
During Phase I (May/June 1992) of the RI, 11 monitoring wells were installed at 7 locations at the Cleburn Street Well site. Eight of the wells (MWs 1A, 1B, 2A, 2B, 3A, 3B, 4A, 4B) were installed as 2-well nests, consisting of a shallow (30 to 34 feet) "A" well and deep (88 to 96 feet) "B" well, at the four potential source areas previously discussed. The three remaining wells consisted of two deep wells (MWs 5B and 6B) northeast of the Cleburn Street well and a shallow well (MW 7A) at the location of the former Oil Dealers Association. The well at the former Oil Dealers Association was installed based on the results of an earlier sampling cone penetrometer survey which indicated potential groundwater contamination at that location (1). The Phase I monitoring well locations are shown in Figure 5.
Following installation, each of the 11 monitoring wells was sampled for VOCs. In November 1992, all of the wells were re-sampled for VOCs as part of the Phase II field activities (1).
In June 1993, 7 additional monitoring wells were installed downgradient of the former One Hour Martinizing building as part of the Phase III RI field investigation (see Figure 6). Six of the wells (MWs 8A, 8B, 10A, 10B, 11A, and 11B) were installed in three, 2-well nests. Each nest contained a shallow (about 30 feet deep) "A" well and a deep "B" well (approximately 85-90 feet deep). The seventh well (MW 9A) was a single shallow monitoring well. Following installation, groundwater samples were collected from all 7 of the new monitoring wells as well as from 8 of the 11 existing monitoring wells (7).
Analysis of the groundwater samples revealed the presence of VOCs in most of the monitoring wells (Table 2). PCE was found in samples from monitoring wells at Liberty Cleaners, One Hour Martinizing, Nebraska Solvents Company, Ideal Cleaners, and former Oil Dealers Association (see Figures 7 and 8 for PCE concentration contours in the shallow and deep monitoring wells, respectively.) The highest PCE concentrations (170,000 ppb) were measured in samples from the shallow (32 feet deep) monitoring well at One Hour Martinizing. The estimated horizontal and vertical extent of PCE contamination originating from the One Hour Martinizing source, based on Phase III groundwater sampling data, is presented as PCE iso-concentration maps in Figures 7 and 8.
Table 2. Contaminant Concentrations in Groundwater from Monitoring Wells1
| Contaminant | Concentration Range (ppb) | Comparison Value | |||||
| Liberty Cleaners2 | 1-Hr Martinizing2 | NE Solvents3 | Ideal Cleaners2 | Oil Dealers Assoc.3 | ppb | Source | |
| Benzene | ND | ND | ND | ND | 20 | 1 | CREG |
| Bromodichloromethane | ND | 2 - 3 | ND | ND | 2 | 0.6 | CREG |
| Bromoform | 1.1 | ND | ND | ND | ND | 4 | CREG |
| Chlorodibromomethane | ND | ND | ND | ND | ND | ||
| Chloroform | ND | 11 - 17 | 1.6 | ND | ND | 6 | CREG |
| Total Trihalomethanes | 1.1 | 13.1 - 20 | 1.6 | ND | 2 | 100 | MCL |
| Chloromethane | ND | ND | ND | 12 | ND | 3 | LTHA |
| 1,1-Dichloroethane | ND | 3.4 - 5 | 4 - 9.1 | ND | ND | None | |
| 1,1-Dichloroethylene | ND | 11 - 37 | 2 - 4.6 | ND | ND | 0.06 | CREG |
| 1,2-Dichloroethylene | ND | 1.5 - 85 | 160 | ND | ND | 70 (cis) | LTHA |
| Tetrachloroethylene (PCE) | 1.1 - 68 | 6 - 170,000 | 80 - 4,100 | 5.3 - 95 | 3.2 | 0.7 | CREG |
| 1,1,1-Trichloroethane | ND | 400 - 540 | 8 - 30 | ND | ND | 200 | LTHA |
| 1,1,2-Trichloroethane | ND | 7.9 - 12 | ND | 2 | ND | 0.6 | CREG |
| Trichloroethylene (TCE) | ND | 1.3 - 410 | 1.1 - 75 | ND | ND | 3 | CREG |
A number of other VOCs, including TCE, 1,1,1-TCA, 1,1-DCE, 1,2-DCE, and THMs, such as chloroform and bromodichloromethane, were also found at significant levels in the shallow One Hour Martinizing monitoring well. Many of these same contaminants were present in samples from the monitoring well at Nebraska Solvents Company but generally at lower levels. At the former Oil Dealers Association location, low levels of PCE and one THM were detected along with benzene, ethyl benzene, toluene, and xylene (BTEX), compounds usually associated with gasoline or petroleum contamination. However, since the ethyl benzene, toluene, and xylene concentrations did not exceed ATSDR's comparison values, these contaminants were not selected as contaminants of concern. At Liberty Cleaners and Ideal Cleaners, other than PCE, only a few low-level VOCs were found in the monitoring well samples.
Groundwater -- Public Wells
Samples from the Pine Street, Lincoln Street, and Cleburn Street municipal wells have been collected on numerous occasions since 1984 when PCE contamination was discovered in the Lincoln Street well. (See Figures 2 and 5 for the location of these three wells.) The Cleburn Street and Lincoln Street wells have been disconnected from the municipal water distribution system since 1986 and 1995, respectively. However, the Pine Street well is still used periodically (during periods of high water demand) to supplement the municipal water supply. As previously discussed, water from this well is pumped into the Pine Street reservoir where it mixes with water from the Platte River well field prior to entering the municipal water distribution system.
Sampling data for the Pine Street, Lincoln Street, and Cleburn Street wells are presented in Tables 3 and 4 below. Table 3 shows sampling results for the Pine Street well and for the Lincoln Street and Cleburn Street wells while they were connected to the municipal system. Table 4 presents sampling data for the Cleburn Street well after it was taken off-line and, therefore, was not contributing water to the municipal water system.
As shown in Table 3, low levels of trihalomethanes and PCE were found in the Pine Street well and in the Lincoln Street and the Cleburn Street wells while they were connected to the municipal distribution system. In recent years, much higher levels of PCE have been detected in the Cleburn Street (Table 4), while VOC levels in the Pine Street well have been mostly not-detectable. PCE levels in the Lincoln Street well have also reportedly increased the last few years; however, ATSDR has no recent sampling data to confirm this. Since the Cleburn Street and Lincoln Street wells are inactive, VOCs in these wells are not currently entering the municipal water supply. However, the VOC plume may eventually spread to the downgradient Pine Street well and impact the municipal water system.
Table 3. Contaminant Concentrations in Pine Street Well, Cleburn Street Well (before taken
off-line in 1986), and Lincoln Street Well (before taken off-line in 1995)1
| Contaminant | Concentration Range (ppb) |
Year Detected2 | Comparison Value | |
| ppb | Source | |||
| Bromodichloromethane | 0.01M - 1.0 | 88 | 0.6 | CREG |
| Bromoform | 4.6 | 88 | 4 | CREG |
| Chlorodibromomethane | 0.02M - 2.7 | 88 | 0.4 | CREG |
| Chloroform | ND | |||
| Total Trihalomethanes | 0.03 - 8.3 | 88 | 100 | MCL |
| Tetrachloroethylene (PCE) | 1.3 - 26.5 | 84,86,87,88,91 | 0.7 | CREG |
Table 4. Contaminant Concentrations in Cleburn Street Well (after taken off-line in 1986)1
| Contaminant | Concentration Range (ppb) |
Year Detected2 |
Comparison Value | |
| ppb | Source | |||
| Tetrachloroethylene (PCE) | 10.0J - 19,000 | 86,87,88,92,93 | 0.7 | CREG |
| 1,1,1-Trichloroethane | 2 - 14.8 | 91,92 | 200 | LTHA |
| 1,1,2-Trichloroethane | 8 | 92 | 0.6 | CREG |
| Trichloroethylene (TCE) | 3.8 - 17.8 | 91,92 | 3 | CREG |
Groundwater -- Public Water Supply Reservoirs
Water samples from the Pine Street reservoir were collected during Phases I and II of the RI and on several previous occasions. The purpose of these samples was to evaluate the quality of water leaving the reservoir for distribution to municipal water users.
As previously discussed, the Pine Street reservoir stores water from the Pine Street well as well as other Grand Island municipal wells. Water is withdrawn from the reservoir, chlorinated, and then pumped into the water distribution system.
As shown in Table 5, low concentrations of THMs (bromoform, bromodichloromethane, chloroform, chlorodibromomethane) and 1,1,2-TCA were found in water samples from the Pine Street reservoir. No other VOCs, such as PCE, were detected in the reservoir. These data suggest that VOCs which have impacted the Cleburn Street, Pine Street, and Lincoln Street municipal wells have not significantly contaminated the municipal drinking water supply.
Table 5. Contaminant Concentrations in Municipal Water Supply Reservoirs (Pine
Street Reservoir)1
| Contaminant | Concentration Range (ppb) |
Year Detected2 |
Comparison Value | |
| ppb | Source | |||
| Bromodichloromethane | 1.1 - 10.6 | 86,87,88,92 | 0.6 | CREG |
| Bromoform | 2 - 12.8 | 86,87,88,92,93 | 4 | CREG |
| Chlorodibromomethane | 2.7 - 9.0 | 86,87,88,92 | 0.4 | CREG |
| Chloroform | 1.0M - 9.1 | 87,88 | 6 | CREG |
| Total Trihalomethanes | 2 - 30.6 | 86,87,88,92,93 | 100 | MCL |
| 1,1,2-Trichloroethane | 3 | 92 | 0.6 | CREG |
Groundwater -- Private Wells
During Phase III of the RI field activities, a groundwater sample was collected from a private well located at a residence upgradient of One Hour Martinizing. This well is reported to be about 60 feet deep and to be used only for outdoor uses such as lawn and garden watering. Analysis of the sample for VOCs detected very low levels of three contaminants - bromoform, bromodichloromethane, and chlorodibromomethane. These compounds, commonly referred to as THMs, are likely to be naturally occurring and unrelated to the Cleburn Street well site contamination.
Sampling data for other private wells in the site area were not available to ATSDR during the development of this health assessment. ATSDR considers this a significant data gap because area private wells, especially those located near the One Hour Martinizing location or the Cleburn Street well, may be affected by site-related groundwater contaminants.
Surface Water
No significant surface waters are present within the Cleburn Street well site boundaries. The nearest major water body is the Wood River, which is located about 2.5 miles southeast of the site. At the present time, water pumped intermittently from the Cleburn Street well for flood control is discharged to the municipal wastewater treatment plant (WWTP) which, in turn, discharges to the Wood River. ATSDR does not have sampling data for VOCs from the WWTP discharges or from the Wood River near the WWTP. However, it is unlikely that VOCs discharged from the Cleburn Street well would significantly impact the Wood River since the contaminant concentrations would rapidly decrease due to volatilization and dilution during transport through the sewer system, treatment in the WWTP, and mixing with the river.
Standing Water
In 1988, two separate samples were taken of standing water (accumulated stormwater runoff and/or shallow groundwater) in an underground traffic light box located just east of the One Hour Martinizing building. This traffic light box tends to intercept stormwater draining from the One Hour Martinizing area to the bottom of the Eddy Street underpass. As shown in Table 6, the first sample, which was collected by the City of Grand Island in March 1988 and held approximately six months before being analyzed, contained very high levels of PCE, 1,1,1-TCA, and TCE. The second sample, obtained during the September 1988 site investigation, showed much lower levels of PCE and 1,1,1-TCA and non-detectable levels of TCE. The September 1988 sample also contained 1,2-DCE and low levels of two THMs - bromodichloromethane and chloroform (5).
Ambient Air
No sampling data for VOCs in ambient air (indoor or outdoor) at the site were available during the development of this public health assessment. For indoor air, this is considered to be a significant data gap since VOCs in soil gas may accumulate inside buildings (e.g., residences, businesses) at areas with significant groundwater and soil contamination (e.g., near One Hour Martinizing location).
Table 6. Contaminant Concentrations in Standing Water in Underground Traffic Light Control Box1
| Contaminant | Comparison Value | |||
| Concentration (ppb) | Concentration (ppb) | ppb | Source | |
| Bromodichloromethane | ND | 1.0M | 0.6 | CREG |
| Bromoform | ND | ND | ||
| Chlorodibromomethane | ND | ND | ||
| Chloroform | ND | 13.0J | 6 | CREG |
| Total Trihalomethanes | ND | 14.0 | 100 | MCL |
| 1,2-Dichloroethene | ND | 110J | 70 (cis) | LTHA |
| Tetrachloroethylene (PCE) | 50,000,000 | 440J | 0.7 | CREG |
| 1,1,1-Trichloroethane | 320,000 | 3.0M | 200 | LTHA |
| Trichloroethylene (TCE) | 180,000 | ND | 3 | CREG |
Except as discussed below, all sampling data evaluated in this public health assessment were from areas inside the defined site boundaries. These areas include the Cleburn Street, Lincoln Street, and Pine Street wells, and the five potential source areas previously discussed. Since no site-related contamination was found outside the site boundaries, no off-site data are presented in this public health assessment.
As previously discussed, traces of VOCs (primarily THMs) have been found in a number of Grand Island municipal water supply wells outside the site boundaries. However, contaminants in these wells, which are a generally several miles south of the site, are not related to contamination at the Cleburn Street and are not present at levels of health concern. As such, the contaminants are outside the scope of this public health assessment and will not be further evaluated.
C. Toxic Chemical Release Inventory (TRI) Review
ATSDR conducted a search of the EPA Toxic Chemical Release Inventory (TRI) database for facilities in Grand Island. The search showed that some facilities in the area release PCE, 1,1,1-TCA, and xylene compounds to the air. TRI records indicated that no VOCs were disposed of in the ground during the reporting period. However, it should be noted that information in the TRI database is reported only by large companies that handle certain quantities of hazardous chemicals. Therefore, it is not possible to determine from the TRI records whether any small businesses have dumped contaminants (such as VOCs) onto the ground in the site area.
The TRI database does not provide sufficient information to estimate airborne concentrations, either at an individual source or downwind of a source. Also, airborne VOC releases are not likely to contribute significantly to groundwater VOC contamination. Therefore, airborne releases identified in the TRI search are not considered further in this assessment.
D. Quality Assurance and Quality Control
The reports and laboratory data sheets ATSDR reviewed indicate that laboratory procedures used to analyze samples from the site included quality control measures. However, that information does not show whether sampling procedures, transport, holding times, and storage were in accordance with accepted quality assurance requirements. For example, one sample taken from the underground traffic light control box was reportedly held for several months before being analyzed. ATSDR has presumed that appropriate protocols were generally followed, and that analytical data are generally accurate. The validity of ATSDR's evaluations, conclusions, and recommendations is contingent upon the completeness and reliability of the available site data and information.
The main physical hazard at the Cleburn Street Well site is the former One Hour Martinizing building. EPA officials report that the dilapidated building has been several holes in its walls, due to neglect and vandalism, which allow unlimited access to the inside. Furthermore, the building has a partially collapsed roof which could endanger anyone entering it. EPA and city officials have received numerous complaints from local residents about the hazardous condition of the building. It is anticipated that the building will either be demolished or repaired in the near future (4).
A less conventional hazard associated with the Cleburn Street Well site is the possibility that soil gases released below ground from contaminated groundwater could rise to the ground surface and accumulate in buildings at levels that could support combustion (explosion). ATSDR's conclusions about combustible gases in structures are discussed later in this assessment.
To determine whether persons are exposed to contaminants from the Cleburn Street well site, ATSDR has evaluated the environmental and human components, or pathways, that lead to human exposure. This pathway analysis considers five elements: 1) a source of contamination; 2) an environmental medium in which contaminants may be present or through which contaminants may be transported; 3) a point of exposure; 4) a route of human exposure; and 5) an exposed population.
ATSDR classifies pathways as completed or potential. For a completed pathway to exist, all five elements must exist, and there must be evidence that human exposure to a contaminant has occurred in the past, is currently occurring, or will occur in the future. A potential pathway exists when at least one of the five elements is missing, or is not clearly defined, but could exist (e.g., exposure to a contaminant could have occurred in the past, could currently be currently occurring, or could occur in the future). A pathway is eliminated when at least one of the five elements is missing and will never exist (e.g., there is no evidence that people have been, are, or will be exposed).
Completed and potential exposure pathways for the Cleburn Street well site are summarized in Tables 7 and 8, respectively. Estimates of the number of exposed persons for completed exposure pathways and the number of potentially exposed persons for potential exposure pathways are shown in Tables 9 and 10, respectively. The discussion that follows these tables includes those exposure pathways considered important or relevant to the site. However, exposure pathways that have been eliminated are also discussed.
Table 7. Completed Exposure Pathways
| PATHWAY NAME |
||||||
| Point of Exposure |
Route of Exposure |
Exposed Population |
||||
| Public Water Supply |
Chemical use, disposal, spillage, and/or leakage | Groundwater | Residences Businesses Industry |
Ingestion Inhalation Skin contact |
Residents Workers Visitors |
Past Present Future |
Table 8. Potential Exposure Pathways
| PATHWAY NAME |
||||||
| Route of Exposure |
Exposed Population |
|||||
| Private Well Water | Chemical use, disposal, spillage and/or leakage | Groundwater | Residences Businesses Industry |
Ingestion Inhalation Skin contact |
Residents Workers Visitors |
Past Present Future |
| Soil gas/ indoor air |
Chemical use, disposal, spillage and/or leakage | Soil to air | Interior of buildings | Inhalation | Residents Workers Visitors |
Past Present Future |
| Worker/ Source chemicals |
Chemical use, disposal, spillage and/or leakage | Chemicals containing VOCs (such as PCE) | Businesses where chemicals were used, disposed, spilled, or leaked | Skin contact Inhalation Ingestion |
Workers | Past Present Future |
| Soil | Chemical use, disposal, spillage and/or leakage | Soil | Areas with contaminated soils (e.g., One Hour Martinizing) | Incidental ingestion; Inhalation | Workers involved in digging, drilling, or excavation activities | Present Future |
| Worker/ Traffic light box |
Chemical use, disposal, spillage and/or leakage | Surface water runoff and/or groundwater | Underground traffic light control box (near Eddy St. underpass) | Inhalation Skin Contact |
Utility workers; Sampling personnel | Past |
Table 9. Estimated Population for Completed Exposure Pathways
| EXPOSED POPULATIONS | AFFECTED BY A COMPLETED EXPOSURE PATHWAY* FOR: | |||
| Location | Estimated Number |
1,1,2-TCA | THMs | Other VOCs (e.g., TCE, PCE) |
| Persons in Grand Island using the municipal water system | 38,000 | Unknown | Public water supply | Unknown/Potential exposure |
Table 10. Estimated Population for Potential Exposure Pathways
| POTENTIALLY EXPOSED POPULATIONS |
|||||||||
| Location | Estimated Number | Benzene | PCE | 1,1,1-TCA, 1,1,2-TCA |
TCE | 1,1-DCA | 1,1-DCE, 1,2-DCE |
Chloro- methane |
THMs |
| Private well users in site area | Unknown | Private well water** | Private well water** | Private well water** | Private well water** | Private well water** | Private well water** | Private well water** | Private well water** |
| Persons who live or
work in areas of the
site underlain by VOC-contaminated groundwater |
Unknown | Soil gas/ indoor air** |
Soil gas/ indoor air** |
Soil gas/ indoor air** |
Soil gas/ indoor air** | Soil gas/ indoor air** | Soil gas/ indoor air** | Soil gas/ indoor air** | Soil gas/ indoor air** |
| Workers in businesses where chemicals containing VOCs were used, stored, spilled, or leaked | Unknown | Worker/ Source chemicals** |
Worker/ Source chemicals** |
Worker/ Source chemicals** |
Worker/ Source chemicals** |
Worker/ Source chemicals** |
Worker/ Source chemicals** |
Worker/ Source chemicals** |
Worker/ Source chemicals** |
| Workers involved in digging, drilling, or excavation activities | Unknown | Not exposed | Soil | Soil | Soil | Not exposed | Soil | Not exposed | Not exposed |
| Persons accessing underground traffic light control box | Unknown | Not exposed | Worker/ Traffic light box |
Worker/ Traffic light box |
Worker/ Traffic light box |
Worker/ Traffic light box |
Worker/ Traffic light box |
Not exposed | Worker/ Traffic light box |
A. Completed Exposure Pathways
Public Water Supply Pathway
As previously discussed, VOCs, primarily THMs and PCE, have been found in the Pine Street, Lincoln Street, and Cleburn Street municipal wells since the mid-1980s (see Tables 3 and 4). VOCs (THMs and 1,1,2-TCA) have also been detected at low levels in the Pine Street reservoir (see Table 5) which is used to store water from the Pine Street well and other Grand Island municipal wells. The Pine Street reservoir also received water from the Cleburn Street and Lincoln Street wells until 1986 and 1995, respectively, when the wells were disconnected from the municipal water system. Water in the Pine Street reservoir is withdrawn as needed, chlorinated, and pumped into the municipal water system for distribution to city water users.
VOC contamination of the Cleburn Street well is believed to originate from the area surrounding the former One Hour Martinizing building. High levels of PCE and other VOCs have been found in soil (see Table 1) and groundwater (see Table 2) at that area which is just upgradient of the Cleburn Street well. The source of contamination at the Lincoln Street well is likely the former Nebraska Solvents Company, while contaminants at the Pine Street well may be associated with the Cleburn Street groundwater plume or some unknown source.
Residents, workers, and visitors who use the public water system are subject to exposure to THMs, 1,1,2-TCA, and possibly other VOCs (such as PCE or TCE) in their drinking water. Although PCE and TCE have not been detected in the municipal water supply, these contaminants have been found in the Cleburn Street well and nearby monitoring wells and could appear in the public water supply in the future.
Exposure to VOCs in the municipal water system is possible by drinking contaminants in the water (ingestion), by breathing contaminants evaporating from the water during showering or other indoor water uses (inhalation), and by absorbing contaminants through the skin during bathing, showering, etc. (dermal contact). It is estimated that up to 38,500 people - the approximate number of persons served by the municipal water system - could be exposed to low concentrations of VOCs from using municipal water. However, since no sampling data are available for VOCs at the users' taps, the actual number of persons exposed and the actual exposure levels are not known. For VOCs such as PCE and 1,1,2-TCA, the levels at the tap are likely much lower than those measured in the municipal water supply wells because of dilution with water from other non-contaminated municipal wells in the Pine Street reservoir. The VOC levels at the tap would also tend to be lower than the levels found in the Pine Street reservoir due to volatilization in the water distribution system. For THMs, however, the levels at the tap may be higher than the levels found in the water supply wells or water supply reservoir because water pumped from the reservoir undergoes chlorination which commonly results in the formation of THMs.
B. Potential Exposure Pathways
Private Well Water Pathway
A few private water supply wells have been identified in the immediate site vicinity. Although most of these wells are reported to be used just for outdoor watering, some of them may be used for indoor water uses, including drinking water. PCE and other VOCs found in groundwater around the Cleburn Street well (see Table 4), the former One Hour Martinizing location, and, to a lesser extent, the former Nebraska Solvents Company location (see Table 2) could impact some of these private wells. If any impacted wells were used for outdoor uses, such as lawn watering or irrigation of home vegetable gardens, significant human exposure to VOCs would be not expected since VOCs tend to evaporate rapidly from water and do not accumulate significantly in fruits or vegetables. However, if such wells were used for household water needs, such as drinking or showering, human exposure to VOCs could occur (see Public Well Pathway discussion).
During the RI, one private well located upgradient of the former One Hour Martinizing cleaners was sampled for VOCs. This well, which was reportedly used for outdoor watering, did not contain any site-related contaminants at levels of concern. Since no other private wells in the site vicinity were sampled, it is not known whether any private wells are actually impacted by site contamination and, if so, to what extent Therefore, at this time, ATSDR cannot fully evaluate potential exposure pathways associated with use of private well water.
Soil Gas/Indoor Air Pathway
At the Cleburn Street well site, PCE has been detected in soil gas at areas where groundwater is contaminated by VOCs. This indicates that PCE is volatilizing from the water table and entering the void spaces of the overlying soil. The highest PCE soil gas levels were found around the former One Hour Martinizing building where groundwater is heavily contaminated with PCE and other VOCs.
PCE and other volatile contaminants migrating upward in soil gases may enter buildings (e.g., residences, businesses) through basement walls, crawl spaces, or foundation cracks, and accumulate inside. Persons living or working in these buildings could then be exposed to the VOCs by breathing the contaminated indoor air. However, since no indoor air data for VOCs are available, it is not known to what extent soil gas VOCs are entering residences and businesses at the site. Therefore, the potential for inhalation exposure to VOCs in indoor air, especially PCE, cannot be evaluated at this time.
No soil gas sampling data are available for estimating potential for combustion. PCE data are available, but that contaminant is not combustible (15). After analyzing potential water/air equilibria, ATSDR estimates that combustible VOCs released from groundwater to the unsaturated soil zone are not likely to be at concentrations at which they would ignite if they subsequently accumulated in overlying structures. Only one water sample, taken from the traffic light control box early in 1988, had concentrations of combustible VOCs great enough to support ignition in ambient air. However, that sample was held for several months before being tested. Because of that departure from protocol, and because a later sample taken at the box contained much lower VOC levels, ATSDR believes the initial sample should not be given substantial weight in this assessment. Ambient air monitoring data are not available, however, to confirm whether explosion potential is an important issue for residences and businesses that are located over areas of groundwater contamination.
Worker/Source Chemicals Pathway
People who worked in businesses where PCE or other volatile chemicals were used or inappropriately disposed of could have been exposed to those contaminants through skin contact and inhalation. Such exposures were especially likely at the One Hour Martinizing cleaners since 1) PCE was used in the dry cleaning operations, 2) PCE spillage inside the business was reported on at least one occasion, and 3) PCE is present at high levels in soil and groundwater beneath the buildings. However, the extent of past exposures (while the business was operating) cannot be evaluated with currently available information. Note: Recent exposures are not likely since this business has been closed and the building vacated for several years.
Soil Pathway
VOCs, primarily PCE, have been found in site soils at the following four locations: One Hour Martinizing, Liberty Cleaners, NE Solvents, and Ideal Cleaners. However, none of the contaminants were present at levels of concern except for PCE in subsurface soils at the One Hour Martinizing location. Moreover, the areas where PCE and other VOCs were found are generally covered by buildings or pavement (asphalt and/or concrete) which prevent direct contact with the contaminated soils. For these reasons, area residents are not likely to be significantly exposed to PCE or any other VOCs in site soils.
Persons involved in extensive digging, drilling, or excavation activities, such as utility personnel or remedial workers, near the One Hour Martinizing building might be exposed to PCE and other VOCs, through incidental ingestion of contaminated soil or through inhalation of contaminants volatilizing from the soil. However, such exposures are expected to be limited since site workers are not likely to come in contact with the most heavily contaminated soils, which are found at a depth of 25-26.5 feet below ground surface. In addition, it is assumed that site workers will take appropriate protective measures when conducting any extensive soil-disturbing activities in significantly contaminated areas.
Worker/Traffic Light Box Pathway
High levels of PCE, 1,1,1-TCA, and TCE have been found in standing water in an underground traffic light control box (see Table 6) just east of and downhill from the former One Hour Martinizing building. Stormwater runoff draining from the One Hour Martinizing area toward the Eddy Street underpass tends to collect in the underground box. In addition, groundwater from the shallow water table may seep into the underground box when the water table is high (e.g., after heavy rains.) Therefore, it is likely that the contaminants found in the traffic light box migrated from the One Hour Martinizing area through stormwater runoff and/or groundwater infiltration.
People who have accessed the traffic box in the past, such as utility maintenance workers or environmental sampling personnel, without proper respiratory or skin protection may have had short-term exposure to PCE, 1,1,1-TCA, and TCE via inhalation and dermal contact. Although such exposures were likely to be brief and infrequent, available information is insufficient to evaluate the extent of these potential exposures.
Groundwater/Surface Water Pathway
As previously discussed, a groundwater extraction well near the former One Hour Martinizing building is being used to prevent groundwater contamination at that location from migrating to downgradient areas. Groundwater pumped from the well is discharged to a sanitary sewer and then to the municipal WWTP which, in turn, discharges to the Wood River. Although water from the well is likely to contain significant levels of PCE and other VOCs, the contaminant levels will decrease rapidly, due to dilution and volatilization, as the water passes through the sewer system, undergoes treatment in the WWTP, and mixes with the Wood River. As a result, the discharges from the extraction well should have little impact on the water quality of the river and should not cause anyone using the river to be significantly exposed to VOCs.
Although the groundwater extraction well helps to control groundwater seepage into the Eddy Street underpass, flooding of the underpass after significant rainfall events has been reported. Flooding of the underpass is caused by accumulated stormwater runoff, which drains from the area surrounding the old One Hour Martinizing building, and excess seepage from the high groundwater table. Since shallow groundwater near One Hour Martinizing and the Cleburn Street well is contaminated with PCE and other VOCs, standing water at the Eddy Street underpass may also contain such contaminants. However, since the flooding occurs on a busy city roadway, and since heavy rainfall will tend to dilute any contamination coming from the One Hour Martinizing area, significant human exposure to contaminants at the underpass is unlikely and will not be evaluated in this public health assessment.
Introduction
This section discusses health issues for persons exposed to specific site contaminants, discusses health outcome data, and addresses specific community health concerns.
To evaluate noncancer health effects, ATSDR has developed a Minimal Risk Level (MRL) for certain contaminants commonly found at hazardous waste sites. The MRL is an estimate of daily human exposure to a contaminant below which noncancer adverse health effects are unlikely to occur. MRLs are developed for routes of exposure and for the length of exposure: acute (less than 14 days), intermediate (15 to 364 days), and chronic (equal to or greater than 365 days). ATSDR presents these MRLs in Toxicological Profiles. These chemical-specific profiles provide information on health effects, environmental transport, human exposure, and regulatory status. If an ATSDR MRL is not available, then EPA's Reference Dose (RfD) is used. The RfD is an estimate of daily human exposure to a contaminant for a lifetime below which (noncancer) health effects are unlikely to occur.
ATSDR estimates cancer risks using EPA's cancer slope factors. EPA has estimated cancer slope factors (CSF) for certain chemicals. CSFs are estimates of a chemical's potency to cause cancer and are used in conjunction with exposure dose to estimate cancer risk of a lifetime of 70 years.
In calculating estimates of exposure to contaminants in water, intake rates of 2 liter/day for adults and 1 liter/day for children were used.
Tetrachloroethylene (PCE)
PCE is a colorless, nonflammable liquid with an ether-like odor. It is practically insoluble in water. PCE is used in dry cleaning and textile processing. It is also used as a cooling gas, an insulating fluid, and in the manufacture of other chemicals and products including fluorocarbons, paint, adhesives, aerosols and coatings. PCE may be formed in small quantities during chlorination of water. It has also been detected in rainwater, sea water, rivers, fruits and vegetables, dairy products, oils, fats, fish, meats, and fresh bread. Potential consumer exposure to PCE may occur through use of coin-operated laundromats containing dry cleaning machines and freshly dry-cleaned clothing (16).
Grand Island residents who used public water before 1986 were probably exposed to low levels of PCE in their drinking water, even though PCE was not detected in the Pine Street reservoir. Prior to 1986, water pumped from the Cleburn Street well was mixed with clean water from other municipal wells in the Pine Street reservoir, thereby diluting any contaminants in the Cleburn Street well water. This may explain why PCE discharged from the Cleburn Street well was never found at detectable levels in the reservoir. Using the highest PCE levels detected in the Cleburn Street well (Table 3), the estimated exposure doses for children are 4 times lower than the chronic RfD and for adults are 13 times lower than the RfD (Table 11) (16). Therefore, adverse health effects are unlikely to occur in children or children exposed to PCE in the municipal water system.
The International Agency for Research on Cancer (IARC) has classified PCE as probably carcinogenic to humans. EPA has classified PCE between a "probable human carcinogen" (based on sufficient evidence in animals and inadequate or no evidence in humans) and a "possible human carcinogen". Using EPA's cancer potency factor for PCE, ATSDR's evaluation indicates that persons exposed to PCE in their drinking water at the levels detected in the Cleburn Street well (Table 3) would have no apparent increase risk of developing cancer (16).
High levels of PCE were detected in the Cleburn Street well after it was taken off-line in 1986 (Table 4) and in soils (Table 1) at the One Hour Martinizing location. (Note: PCE was also found in soils at three other locations - Liberty Cleaners, NE Solvents, and Ideal Cleaners - but at much lower levels.) However, since the Cleburn Street well is no longer connected to the municipal water supply system, exposure to PCE from the well is not a concern. In addition, PCE in site soils is generally confined beneath buildings or paved parking areas. Therefore, Grand Island residents are unlikely to be exposed to PCE in site soils. Persons involved in extensive digging, drilling, or excavation activities, such as utility personnel or remedial workers, in areas where soil contamination is present (e.g., around the One Hour Martinizing building) might be exposed to VOCs. Such exposures should not pose a health hazard if appropriate protective measures are used during the soil-disturbing activities.
PCE was also found at high levels in groundwater (Table 2) at the One Hour Martinizing and NE Solvents locations, and to a much lesser extent at Liberty Cleaners, NE Solvents, and Ideal Cleaners. Although few people in the site area use private wells for their water needs, it is not known whether any private wells are actually in use near the areas of PCE groundwater contamination and, if so, to what extent such wells have been impacted by the contamination. Therefore, at this time, ATSDR cannot evaluate whether potential exposure to PCE poses a health threat to private well users at the site.
Although air quality data are not available for the underground traffic light control box, it is possible that fumes from the very high levels of PCE (50,000,000 ppb) detected in standing water inside the box could have posed a short-term inhalation health risk to environmental sampling staff or utility workers who may have opened the box without proper respiratory protection. However, it is difficult to determine the potential health effects of such an exposure in the absence of ambient air samples.
Bromodichloromethane (BDCM)
BDCM is a colorless liquid that is not readily flammable. It is soluble in water, alcohol, ether, acetone, benzene and chloroform. BDCM is used in the manufacturing of organic chemicals and as a reagent in laboratory research. It has been used to separate minerals and salts, as a fire retardant, in fire extinguishers, and as a solvent for waxes, fats, and resins. However, it is not currently listed as an ingredient in solvents, fire extinguishers, or other commercial products (17).
Since BDCM is not produced or used on a large commercial scale it is unlikely that significant release into the environment will result from industrial processes. The major environmental source of BDCM (and other trihalomethanes) is its formation as a result of the chlorination of drinking, waste, or cooling waters. Consumers are also potentially exposed to BDCM from contaminated food and beverages prepared with chlorinated water containing low levels of BDCM. Exposure can also occur from dermal contact with and ingestion of chlorinated swimming pool water (17).
Grand Island residents using public water have been and may currently be exposed to low levels of BDCM in their drinking water. The estimated exposure doses for adults and children, based on the highest BDCM levels measured in the Pine Street reservoir (Table 5), are 20 times lower than the MRL or the RfD (Table 11). Therefore, adverse health effects are not likely to occur in adults and children exposed to the low levels of BDCM in municipal water.
Although BDCM is classified as a probable human carcinogen by EPA, exposure to BDCM at the levels found in the municipal water system should not present an increased cancer risk.
Potential exposure to the trace amounts of BDCM detected in standing water inside the underground traffic light control box (Table 6) is insignificant.
Low levels of BDCM have also been found in groundwater at the One Hour Martinizing and Oil Dealers Association locations (Table 2). However, significant exposure is not likely based on the low groundwater levels detected and the fact that few people in the site area use private wells for their water needs.
Bromoform
Bromoform (also known as tribromomethane or methyl tribromide) is a colorless to yellow liquid with a chloroform-like odor. Bromoform is used in pharmaceutical manufacturing, as an ingredient in fire-resistant chemicals and gauge fluid, and as a solvent for waxes, greases, and oils. Currently, bromoform is only produced in small amounts for use in laboratories and in geological and electronics testing. When chlorine is added to drinking water to kill any disease-causing organisms which might be present, the chlorine reacts with natural substances present in the water, producing low levels of bromoform as undesired by-product. In the environment, bromoform is either dissolved in water or evaporated in air where it can cause other chemicals to breakdown slowly. Any bromoform in water or soil may also be broken down by bacteria, although the extent of this process is not known (18).
Grand Island residents using public water have been and may still be exposed to low levels of bromoform in their drinking water. The estimated doses for adults and children, using the highest levels of bromoform detected in the Pine Street reservoir (Table 5), do not exceed the MRL or the RfD (Table 11). Therefore, no adverse health effects are expected to occur from exposure to low levels of bromoform in municipal water.
Although bromoform is classified as a probable human carcinogen by EPA, if residents ingested the maximum level of bromoform detected in the municipal water system for 70 years, they would have no significant increased risk of cancer.
Low levels of bromoform have also been found in groundwater at the Liberty Cleaners location (Table 2). However, significant exposure is not likely based on the low groundwater levels detected and the fact that few people in the site area use private wells for their water needs.
Chlorodibromomethane (CDBM)
CDBM is a colorless, heavy, nonflammable liquid with a sweetish odor. CDBM was used to in the past to make chemicals such as fire extinguisher fluids, spray can propellants, refrigerator fluid, and plasticides. Currently it is produced only in small quantities for use in laboratories. When chlorine is added to drinking water to kill any germs, the chlorine reacts with the natural substances in the water to produce CDBM as undesired byproduct. Small amounts of CDBM are also produced by plants the ocean. In the environment, CDBM like all trihalomethanes (THMs), is found dissolved in water or evaporated in air. When CDBM enters soil or water, it is broken down by bacteria, although the extent of this process has not been adequately determined (18).
Grand Island residents using public water have been and may still be exposed to low levels of CDBM in their drinking water. The estimated doses of CDBM, using the highest levels detected in the Pine Street Reservoir (Table 5), are far lower than the chronic MRL or the RfD (Table 11). Therefore, adverse health effects are unlikely to occur from exposure to low levels of CDBM in municipal water.
Although the EPA considers CDBM to be a possible carcinogen based on animal studies only, the International Agency for Research in Cancer (IARC) has not classified CDBM as a carcinogen. People exposed to the low levels of CDBM found in the municipal water system should have no increased risk of cancer.
Chloroform
Chloroform, which is also known as trichloromethane, methane chloride, or methyltrichloride, is a colorless, volatile, nonflammable liquid. It is slightly soluble in water and has a pleasant, non-irritating odor. Chloroform was used as an anaesthetic in the past but its use has been discontinued. Chloroform enters the environment from chemical companies, paper mills, waste water from sewage treatment plants, and drinking water that contains chlorine. Potential human exposure may occur from breathing air contaminated with chloroform, eating food or drinking water containing chloroform, or by absorption of chloroform through the skin. Chloroform is very persistent in both air and groundwater (19).
Grand Island residents using public water have been and may be currently exposed to low levels of chloroform in their drinking water. However, the estimated ingestion doses for children and adults, based on the highest chloroform levels detected in the Pine Street reservoir (Table 5), are substantially lower than the chronic oral MRL or RfD (Table 11). Therefore, adverse health effects are unlikely to occur from exposure to low levels of chloroform in municipal water.
Chloroform detected in the municipal water system is unlikely to cause any increased risk of cancer in residents who use municipal water.
Potential exposure to chloroform detected inside standing water in the underground traffic light control box (Table 6) is insignificant.
Low levels of chloroform have also been found in groundwater at the One Hour Martinizing and NE Solvents locations (Table 2). However, significant exposure is not likely based on the low groundwater levels detected and the fact that few people in the site area use private wells for their water needs.
1,1,2-Trichloroethane (1,1,2-TCA)
1,1,2-TCA is a colorless, sweet-smelling liquid that does not burn easily. 1,1,2-TCA is used mostly where 1,1-dichloroethane (vinylidene chloride) is made. 1,1,2-TCA may also be formed in landfills when 1,1,2,2-PCA is broken down. When 1,1,2-TCA is released into the environment, most of it finally ends up in the air, but some may enter groundwater. Breakdown in air, soil, and groundwater is slow (20).
Grand Island residents who use municipal water are probably exposed to low levels of 1,1,2-TCA in water from the Pine Street water supply reservoir (Table 5). However, the estimated doses for children and adults are substantially lower than the chronic RfD (Table 11). Therefore, adverse health effects are unlikely to occur because of exposure to low levels of 1,1,2-TCA in municipal drinking water.
Although the EPA considers 1,1,2-TCA a possible human carcinogen based on animal studies alone, IARC and the National Toxicology Program (NTP) of the U.S Department of Health and Human Services (DHHS) have not classified 1,1,2-TCA as a carcinogen. Residents exposed to 1,1,2-TCA in municipal water should not have an increased risk of developing cancer.
Low levels of 1,1,2-TCA have also been found in groundwater at the One Hour Martinizing and Ideal Cleaners locations (Table 2). However, significant exposure is not likely based on the low groundwater levels detected and the fact that few people in the site area use private wells for their water needs.
Other Volatile Organic Compounds (VOCs)
1,1,1-Trichloroethane (1,1,1-TCA) (320,000 ppb) and trichloroethylene (TCE) (180,000 ppb) were other VOCs detected in water in the underground traffic control box (Table 6). As a mixture, these contaminants could have posed a short-term inhalation health risk to environmental sampling staff or utility workers who may have opened the box without proper respiratory protection (21,22). However, the potential health effects of such exposures cannot be determined because air quality data from inside the box are unavailable.
1,1,1,-TCA, TCE, and a number of other VOCs were detected in soil (Table 1) and in groundwater (Table 2) at One Hour Martinizing, and to lesser extent, at one or more of the following locations: NE Solvents, Ideal Cleaners, and Oil Dealers Association. Grand Island residents are unlikely to be exposed to such VOCs in site soils since the contaminants are generally confined beneath buildings or paved parking areas. Persons involved in extensive digging, drilling, or excavation activities, such as utility personnel or remedial workers, in areas where soil contamination is present might be exposed to VOCs. Such exposures can be minimized through the use of appropriate protective measures (where required by specific site conditions).
Few people in the site area use private wells for their water needs; however, it is not known whether any private wells are actually in use in those areas where groundwater is contaminated with VOCs (such as the One Hour Martinizing location) and, if so, to what extent such wells have been impacted by the contamination. Therefore, at this time, ATSDR cannot evaluate whether potential exposure to 1,1,1-TCA, TCE, and other VOCs poses a health threat to private well users at the site.
Table 11. Comparison of Estimated Exposed Dose to Health Guidelines for Municipal
Water System Users
| Contaminant | Exposure Pathway |
Health Guideline for Ingestion - mg/kg/day | ||
| Value | Source | Exceeded by Estimated Exposure Dose | ||
| Bromodichloromethane | Municipal water system | 0.02 | MRL*/ RfD** | No |
| Bromoform | Municipal water system | 0.2 0.02 |
MRL RfD |
No No |
| Tetrachloroethylene | Municipal water system | 0.01 | RfD | No |
| Chlorodibromomethane | Municipal water system | 0.03 0.02 |
MRL RfD |
No No |
| Chloroform | Municipal water system | 0.01 | MRL/RfD | No |
| 1,1,2-Trichloroethane | Municipal water system | 0.004 | RfD | No |
B. Health Outcome Data Evaluation
Review of the Nebraska cancer incidence and mortality records for the period 1985 to 1990 (Tables 12 and 13) did not show any statistically significant excess cancer incidence or mortality rates in Hall County compared with either state or national rates. The rates for Hall County are probably considered representative of Grand Island because its population of approximately 39,400 is about 80% of the county's 49,500 resident population.
Table 12. Total Cancer Incidence (1987-1989) and Cancer Mortality Rates (1985-1989)
for Colon/Rectal and Bladder Cancers in Hall County, State of Nebraska,
and United States (1987)
| Area of Consideration |
|||||
| Incidence Rate* | Mortality Rate* |
Incidence Rate* |
Mortality Rate* |
Significant Excess Compared To: | |
| Hall County | 46.1 | 15.8 | 12.0 | 2.2 | |
| Nebraska | 45.8 | 18.5 | 14.2 | 3.0 | No |
| United States | 49.0 | 19.9 | 9.4 | 6.3 | No |
Table 13. Total Cancer Incidence (1987-1990) and Cancer Mortality Rates (1986-1990)
for Liver/Gallbladder Cancer and Combined Cancer Sites in Hall County,
State of Nebraska, and United States (1987)
| Area of Consideration |
|||||
| Incidence Rate* |
Mortality Rate* |
Incidence Rate* |
Mortality Rate* |
Significant Excess Compared To: | |
| Hall County | 2.2 | 1.6 | 306.0 | 173.1 |
|
| Nebraska | 3.2 | 3.4 | 336.2 | 157.3 | No |
| United States | 2.7 | 4.3 | 377.2 | 169.3 | No |
C. Community Health Concerns Evaluation
We have addressed each of the community concerns about health as follows:
No, the addition of a cancer treatment center to the hospital is in response to the recognition of cancer as the second leading cause of death in the United States including Nebraska. Mortality rates have continued to increase nationwide during the 1980s, almost entirely as a result of the rising number of lung cancer deaths (9). Analysis of cancer data for the period between 1985 and 1990 (Tables 12 and 13) indicates that incidence and mortality rates of all cancer types or specific cancer types did not differ significantly when the rates for Hall county are compared with those for state or federal rates. The Nebraska Cancer Registry which began collecting data in 1987 is relatively new and is incomplete in years and data necessary to determine trends in cancer incidence.
In addition, toxicological evaluation of the available environmental data for the Cleburn Street well site does not indicate that residents have been exposed to contaminants in drinking water at levels which might cause adverse health effects such as cancer. However, environmental data and other pertinent information for private wells and other pathways through which people might be exposed to site contaminants are presently unavailable.
Yes, it is safe to use the water for all domestic purposes including canning and vegetable watering. Public supply wells that were found to contain low levels of VOCs were disconnected from the municipal water distribution system in 1986. Plants do not significantly take up or bioaccumulate VOCs. In addition, VOCs volatilize readily, especially when aerated or heated, which would also reduce their presence in the water. As discussed in the Pathways Analyses section, the potential for people to be exposed to contaminants via the food chain is not significant.
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