PUBLIC HEALTH ASSESSMENT
CLEBURN STREET WELL SITE
GRAND ISLAND, HALL COUNTY, NEBRASKA
The Cleburn Street Well site is an area in the central part of Grand Island, Nebraska, where groundwater is contaminated with VOCs, primarily PCE. The main area of contamination originated at the former One Hour Martinizing dry cleaners property and has since spread to the Cleburn Street municipal well. In addition, several areas of less extensive VOC contamination, which have impacted two other municipal wells, are also present at the site.
The Agency for Toxic Substances and Disease Registry considers the Cleburn Street well site an indeterminate public health hazard because although available environmental sampling data and health outcome data do not indicate that people have been exposed to site contamination at levels that would be expected to cause adverse health effects, sampling data are not available or not sufficient for some environmental media to which people may be exposed.
Residents of Grand Island using municipal water have been and may still be exposed to low levels of VOCs, including trihalomethanes (bromoform, bromodichloromethane, chloroform, and chlorodibromomethane), 1,1,2-trichloroethane, and possibly PCE, in their drinking water. Although no adverse health effects are expected based on the contaminant levels measured in the municipal water system, the contaminant levels at the point of exposure (i.e., at the tap) are not known.
Potential exposure to site-related contaminants is also possible for 1) residents in the site area who use private well water for their household water needs (e.g., drinking, showering); 2) persons living or working in areas where groundwater is contaminated by VOCs, especially PCE, due to soil gas infiltrating their residences or places of business and contaminating their indoor air; 3) persons who worked in businesses where PCE or other volatile chemicals were stored, used, or disposed of, such as the One Hour Martinizing dry cleaners; and 4) persons, such as remedial site workers or city utility personnel, working in areas with significant VOC contamination including soils at the One Hour Martinizing building and standing water inside the nearby underground traffic light control box. However, the public health significance of those potential exposures cannot be fully evaluated with currently available information.
As part of the site investigation, ATSDR conducted one-on-one public availability meetings to gather community health concerns about the site. Health concerns raised at the meetings are addressed in the Public Health Implications section of this public health assessment.
Based on the findings of this public health assessment, ATSDR has made recommendations to 1) further characterize contaminant levels in municipal tap water, private well water, and indoor air; 2) prevent further contamination of water supply wells and to prevent use of contaminated groundwater for drinking water supplies; and 3) protect residents and site workers from potential exposure to site contaminants.
ATSDR has determined that no follow-up health activities are indicated at this time because exposure to site contamination in the past and present is not expected to cause adverse health effects. However, if additional information becomes available in the future which indicates that human exposure to hazardous substances is occurring or has occurred at levels of public health concern, ATSDR will reevaluate the site for appropriate follow-up activities.
The Agency for Toxic Substances and Disease Registry (ATSDR), whose headquarters are in Atlanta, Georgia, is a federal agency within the U.S. Department of Health and Human Services and is authorized by the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) to conduct public health assessments of hazardous waste sites. As part of that mandate, ATSDR has evaluated the public health significance of the Cleburn Street Well site (e.g., are health effects possible?) and has recommended actions to reduce or prevent possible health effects.
The Cleburn Street Well site is an area in downtown Grand Island, Nebraska, where groundwater has been contaminated by Volatile Organic Compounds (VOCs), primarily tetrachloroethylene (PCE). As shown in Figure 1, the site covers approximately 130 blocks and is bounded on the north by 10th Street, on the south by Division Street, on the east by Pine Street, and on the west by Adams Street (1). The site area is comprised mainly of single family residences, retail shops, and light industry (1,2). The site includes three municipal water supply wells - the Cleburn Street well, the Pine Street well, and the Lincoln Street well (Figure 2) - which have been impacted by VOC contamination. Of these three wells, the Cleburn Street well, located at the intersection of Cleburn Street and North Front Street, is most affected by site contaminants (3). The Cleburn Street and Lincoln Street wells are no longer in use, while the Pine Street well is used during peak demand periods to supplement the municipal water supply (2,4).
PCE was detected initially in the Lincoln Street well (at 6.6 micrograms/liter [ug/l]) in April 1984 during sampling by the Nebraska Department of Health (NDOH). Subsequent tests conducted in March 1986 by the NDOH found PCE in the Cleburn Street well at 21.9 ug/l. In April 1986, follow-up sampling by the NDOH found PCE at 3.5 ug/l in the Lincoln Street well and at 26.5 ug/l in the Cleburn Street well. As a result, the Cleburn Street well was disconnected from the municipal water system (5). Subsequent samples from the Cleburn Street well in September 1986, August 1987, and March 1988, contained PCE at levels ranging from 15 to 25 ug/l.
During a March 1988 site investigation, several potential sources of VOCs were identified near the Cleburn Street well, and more than 20 such sources were identified within a 3-mile radius (5). A soil gas investigation conducted in September 1988 indicated three separate areas of PCE soil gas contamination (Figure 3) in the general vicinity of the Cleburn Street well. The investigation identified four potential sources associated with the PCE soil gas plumes (see Figure 3): 1) the former One Hour Martinizing dry cleaners located at the intersection of North Eddy Street and West 4th Street; 2) the former Nebraska Solvents Company located at the intersection of Lincoln Street and North Front Street; 3) Liberty Cleaners located at the intersection of North Eddy Street and West 8th Street; and 4) Ideal Cleaners located at the intersection of Cedar Street and West 1st Street. The highest PCE soil gas concentrations were around the One Hour Martinizing building, which is located approximately 150 feet northwest of the Cleburn Street well. In addition, very high levels of PCE were found in March 1988 samples of standing water inside an underground traffic light box just east of One Hour Martinizing. Follow-up water samples collected in September 1988 from the traffic light box also contained significant levels of PCE (1).
In July 1991, the Cleburn Street Well site was proposed to EPA's National Priorities List (NPL). The NPL is the national list of hazardous waste sites that qualify for cleanup under the federal Superfund program. The site was listed as final on the NPL in October 1992 (2).
During 1992 and 1993, EPA conducted a remedial investigation (RI) of the Cleburn Street Well site. The purpose of the RI was to characterize the nature and extent of contamination at the site and to evaluate potential risks to human health posed by such contamination. Phase I field activities, conducted in May and June 1992, included installation of 11 monitoring wells and collection of soil, groundwater, and municipal water samples. As part of the Phase II field activities, which were conducted in November 1992 and January 1993, additional groundwater and municipal water samples were collected. The results of the Phase I and Phase II investigations indicated soil and/or groundwater contamination at the four potential source areas previously identified and at an additional location - the former Oil Dealers Association at the intersection of North Front Street and Clark Street. The greatest soil and groundwater contamination was generally found near the former One Hour Martinizing building and, to a lesser extent, near the former Nebraska Solvents Company location (1,6).
Additional RI field activities (Phase III) were conducted in June 1993 to further characterize the extent of soil and groundwater contamination at the One Hour Martinizing location. The Phase III activities included the installation of 7 additional monitoring wells, collection of 53 soil samples from 17 soil probe locations, and collection of groundwater samples from the monitoring wells and 2 municipal wells (1,7). The Phase III sampling results were consistent with the Phase I and Phase II results and suggested that contaminants from the former One Hour Martinizing cleaners were the main source of groundwater contamination associated with the Cleburn Street well. However, contaminants from the former Nebraska Solvents Company may also have contributed to the Cleburn Street well contamination. The other three areas of concern - Liberty Cleaners, Ideal Cleaners, and the former Oil Dealers Association - were determined to be small, isolated areas of groundwater contamination which were not associated with the Cleburn Street well contamination (1,7).
Note: During the Phase I field activities, groundwater samples were also collected from existing monitoring wells at the Grand Island fire station, located about 5 blocks southeast of Ideal Cleaners (see Figure 2). The monitoring wells were originally installed to monitor groundwater quality near the fire station's underground storage tank. Sampling data from the fire station monitoring wells will not be evaluated in this public health assessment since the wells are outside of the site boundaries and are not impacted by site-related contamination.
As previously discussed, the Cleburn Street well was used to supplement the municipal water supply until April 1986 when it was disconnected from the municipal water system. However, the Cleburn Street well was still pumped intermittently to lower the local groundwater table in order to help prevent flooding at the Eddy Street underpass, located about one block southwest of the Cleburn Street well. Water pumped from the well was discharged into an adjacent storm sewer and eventually into the Wood River, which is approximately 2 miles southeast of the city (5). In September 1992, use of the Cleburn Street well for de-watering the underpass was discontinued due to increasing PCE levels in the well (1). In 1993, pumping of the Cleburn Street well resumed to control flooding at the Eddy Street underpass. However, all water produced from the well was discharged to the municipal wastewater treatment plant via the sanitary sewer system.
In July 1993, EPA initiated a removal action at the site to prevent groundwater contamination at the One Hour Martinizing source area from spreading to downgradient water supply wells such as the Pine Street municipal well. The removal action involved the installation of a groundwater extraction well at the One Hour Martinizing location. Since its installation, the extraction well has been pumped at a rate of approximately 50 gallons per minute (gpm). Water from the well is discharged to the sanitary sewer system for treatment by the municipal wastewater treatment plant. Operation of the Cleburn St. well has been discontinued because pumping of the extraction well to contain the groundwater contamination plume also effectively controls flooding at the Eddy Street underpass.
In 1995, the Lincoln Street municipal well, which is located about 1,200 feet from the Cleburn Street well, was shut down reportedly because of PCE contamination. As such, the Lincoln Street well no longer contributes to the municipal drinking water system (2,4).
Note: The Cornhusker Army Ammunition Plant, another NPL site, is located about 6 miles west of Grand Island. ATSDR has issued a public health assessment (final release August 1992) of the ammunition plant, including related contaminated groundwater that extends into the Capital Heights section of Grand Island. The location of the Capital Heights area is shown in Figure 2. Contamination associated with the Cornhusker site will not be evaluated in this public health assessment of the Cleburn Street well site.
On January 14, 1992, Steve Richardson, Bill Greim, and Don Gibeaut, ATSDR headquarters staff, and Roberta Erlwein, former ATSDR Region VII representative, visited the Cleburn Street Well site. Pertinent information obtained during that visit is described in appropriate sections of this document.
Grand Island, with a population of nearly 40,000, is about 90 miles west of Lincoln, the state capital, and is the largest city in central Nebraska. The population is about 96% white, about 1% Asian or Pacific Islander, less than 0.5% African-American, and less than 0.5% Native American. A city map shows that there are about 10 public parks, 20 schools, and a community college in the area. About half of the area shown is residential, and half is commercial/light industry.
Residential, commercial, and light industry are the dominant land uses in the site area. Beyond the city limits, land use is almost exclusively agricultural, principally feed grains and livestock.
Natural Resource Use
Residents of Grand Island use groundwater from either the public (municipal) water supply or private wells for their water needs. Most residents (approximately 38,500) are served by the city's municipal water system which draws water from the alluvial aquifer. In the Grand Island area, this aquifer is composed of sand, gravel, silt, and clay. The depth to groundwater varies from less than 10 feet to greater than 150 feet below ground surface while the thickness of the aquifer ranges from about 80 to 310 feet (3). In the vicinity of the site, the alluvial aquifer, with an average saturated thickness of 70 feet, is comprised primarily of highly permeable sand and gravel and is underlain by an extensive clay layer. The aquifer extends from the groundwater surface, at a depth of 15 to 22 feet below ground surface, to the top of the confining clay layer, which is encountered at a depth of 87 to 94 feet. The clay aquitard unit has a thickness ranging from about 145 to 155 feet. The regional groundwater flow direction is northeast, while local groundwater flow is more toward the east-northeast. However, cones of depression created by operation of municipal wells, such as the Cleburn Street well, may produce local changes in the groundwater flow.
According to Grand Island utility representatives, the municipal water system currently consists of 27 wells, ranging in depth from 90 to 130 feet, and 4 reservoirs (one of which serves as a flow equalization tank). Eleven of the wells are within the Grand Island city limits, while the other 16 (the Platte River Island Well Field) are several miles southwest of the city. The reservoir capacities range from about 1 to 3 million gallons. The locations of the 11 in-town wells are shown in Figure 1.
Nine of the 11 municipal wells within the city limits are high pressure wells which pump directly into the distribution system (following chlorination at the well heads). The remaining 2 wells are the low pressure Pine Street and Lincoln Street wells which pump into the Pine Street reservoir. (The Cleburn Street well also pumped to the Pine Street reservoir prior to April 1986.) The 16 wells at the Platte River also pump to the Pine Street reservoir and to two other reservoirs. Water drawn from the reservoirs is chlorinated and then pumped into the water distribution system.
The Cleburn Street, Lincoln Street, and Pine Street wells are the only municipal wells located within the site boundaries, and are the only municipal wells affected by site-related VOC contamination. In addition, the Pine Street reservoir is the only reservoir which receives water from the Lincoln Street and Pine Street wells. Although traces of VOCs, primarily trihalomethanes (THMs), have been found periodically in other Grand Island municipal wells, the contaminants were not related to the site and the contaminant levels were not above federal drinking water standards. Therefore, contaminants associated with municipal wells and the reservoirs outside the site boundaries will not be evaluated further in this public health assessment.
Approximately 1,100 residents in the Grand Island area are not served by the municipal water system and, therefore, depend on private wells for their household water needs (3). Most of these private wells, which also draw from the shallow alluvial aquifer, are located more than a mile south of the Cleburn Street well and are not affected by contamination from the site (6). In the immediate site vicinity, a few residents have private wells for outdoor watering, and one residence is reported to use a private well for all their household water needs, including drinking water. This well is believed to be several blocks east of Liberty Cleaners and is not likely to be impacted by any site-related groundwater contamination (3,8).
Groundwater is also used extensively in the Grand Island area for agricultural purposes. Specifically, more than 300 wells are used within 4 miles of the site for irrigation of food and feed crops (3).
The nearest significant surface water to Grand Island is the Wood River, which, as previously mentioned, is about 1 mile southeast of the city limits and about 2.5 miles southeast of the Cleburn Street well. This small river flows northeast and is a tributary of the Platte River. It is not known whether the Wood River is used for recreational activities such as swimming, boating, or fishing.
The State of Nebraska operates a cancer registry and keeps vital health statistics records. Data are available in the 1989 annual report of the cancer registry (9). The annual report summarizes cancer incidence and mortality rates at the state and county levels. Additional and more current incidence rates were obtained through the Nebraska Department of Health (10). The vital statistics report is available for 1989 and includes information on births and deaths based on county and state (11).
On January 14, 1992, ATSDR staff held a public availability meeting to gather community concerns about the Cleburn Street Well site. Residents attending the availability meeting raised the following health-related questions:
- Is the increased incidence of cancer in the area related to the Cleburn Street well contamination? Is this why the hospital added a cancer treatment unit last year?
- Is it safe to use the municipal water for canning and vegetable gardening?
Although a resident also raised questions about property values, these questions will not be addressed in this document because ATSDR public health assessments focus on public health. However, the resident was referred to EPA officials for answers to these questions.
During the January 1992 site visit, ATSDR staff also contacted state and local officials to gather additional information regarding health concerns about the site. These officials indicated that some complaints had been reported in the past about the taste of the municipal water; however, the complaints were not believed to be related to the Cleburn Street Well contamination.
Note: The Cleburn Street Well public health assessment was made available for public review and comment at the Edith Abbott Library in Grand Island, Nebraska, from February 7 to March 14, 1997. At that time, the public heath assessment was also provided to the U.S. Environmental Protection Agency, the State of Nebraska Department of Health and Department of Environmental Quality, the Hall County Health Department, and the City of Grand Island for review and comment. ATSDR received no comments on the public health assessment during the public comment period.