HEALTH CONSULTATION
PEACH AVENUE RAILROAD UNDERPASS
(a/k/a COLUMBIA PROPANE MGP SITE)
MARSHFIELD, WOOD COUNTY, WISCONSIN
The construction of a railroad underpass, planned in Marshfield, Wisconsin, will encounter coal tar wastes remaining from a manufactured gas plant (MGP) formerly located adjacent to the underpass site. Environmental health hazards include the potential release of MGP-related volatiles and dust to ambient air, the accumulation of polycyclic aromatic hydrocarbons (PAHs) on soils of nearby residences and playgrounds, potential effects to the aquifer used by the Marshfield municipal water utility, and potential exposure related to the underpass lift station. A site management plan is recommended that includes monitoring and control of dust, PAHs, and volatile hydrocarbons. DHFS also recommends that the ABC Childcare Center be relocated during the removal of MGP waste, that the surrounding aquifer be monitored for long-term effects to the regional water supply, and that water and gases at the underpass lift station be monitored for volatile contaminants.
BACKGROUND AND STATEMENT OF ISSUES
The Wisconsin Department of Health and Family Services, Division of Public Health (DPH), was asked by the Wisconsin Department of Natural Resources (WDNR) for assistance in assessing public health hazards associated with the construction of a railroad underpass in Marshfield, Wood County, Wisconsin. The underpass will pass beneath the Soo Line Railroad at its intersection with Peach Avenue (figure 1). The underpass is a joint project of Marshfield and the Wisconsin Department of Transportation (DOT), and is scheduled to begin early in 2003. Environmental assessments of the site (Dames & Moore 2000; RMT 2002) suggest that the work will encounter coal tar wastes remaining from a manufactured gas plant (MGP) formerly located adjacent to the underpass site. Potential environmental health hazards stem from the plan to excavate these coal tar wastes found in soil and groundwater near the railroad-Peach Avenue intersection. The environmental health issues and plans to partially remediate this former MGP site were described in a previous ATSDR Public Health Consultation (Thiboldeaux, 2002). During the spring of 2002, this MGP site was partially remediated by the energy utility company that owns the property. At that time, coal tars, buried structures, and contaminated soil beneath the Peach Avenue MGP site were removed.
As described previously (Thiboldeaux, 2002), the surrounding area is a residential community bisected by a wide industrial and railroad corridor (figure 1). The underpass site lies within this corridor. A residential neighborhood of mostly single-family houses is located to the north across Arnold Street. Pickle Pond Park, a playground, is northeast of the site across Peach Avenue. Adjacent to, and north of, the former MGP site are a building supply company and a child care center (figure 1). Vacant lots and residential neighborhoods lie further west of the site. The residential and working population is estimated from maps (Dames & Moore 2000) to be 100-150 people within a 100-yard radius, and 400-550 people within 300 yards.
Public Health Issues
Discussions in this public health consultation include those on several aspects of the Peach Avenue underpass project anticipated to be potential health issues as this work proceeds. These are:
Potential release of MGP-related volatile organic compounds to ambient air. Soil contaminants detailed in the Laboratory Analysis Reports and Summaries (RMT, 2002) indicate that coal tars remain in areas to be excavated within Peach Avenue. The most concentrated areas, containing benzene, naphthalene, benzo(a)pyrene, and other coal tar components (table 1), are near the buried structure removed by NiSource in 2002. Lower concentrations of coal tars were detected in adjacent soil areas (RMT 2002, data not shown). Previous experience at this and other MGP sites predicts that air releases will occur during excavation and removal of coal tars. In the interest of public health, the DOT workplan should include means to monitor and manage such air releases (see Thiboldeaux and Nehls-Lowe, 2002). MGP wastes contain mixtures of compounds, each having varying properties of vapor pressure, olfactory sensitivity, and toxicity. Odors released from MGP excavation sites are often regarded as nuisances. However, it is important to recognize that smelling an odor also represents a legitimate and verifiable inhalation exposure, the effects of which depend upon the concentration and the toxic mechanism of the substance inhaled. Several volatile compounds which may be encountered during excavation at this site, including benzene, naphthalene, and toluene, may cause acute health effects such as dizziness or nausea. Benzene, which will be encountered in high concentration at some locations on site (table 1), is also an EPA class-A carcinogen.
The nearby receptors for potential air impacts are the children and workers at ABC Childcare Center, as well as people at other nearby businesses and houses. As during the previous round of excavation, the ABC Childcare Center should be temporarily relocated during that portion of the underpass project in which coal tar will be encountered. During the previous (2002) excavation, site visits and reports from neighbors indicated there were occasional air releases sufficient to cause health effects such as eye and throat irritation in the nearby neighborhood. This was observed even though the work employed state-of-the-art air control techniques. In the case of the underpass work, should the prediction of less coal tar and petroleum contamination prove true, then the removal of these materials should proceed smoothly, and the length of the relocation can be shortened. No one can predict with certainty the risks associated with encountering chemical hazards during the planned excavation. However, moving the childcare center in advance will avoid unplanned, costly delays and other problems caused by extended air releases from unexpected contaminants. Given the uncertainty in the degree of contamination, DHFS considers these recommendations prudent.
Air deposition of polycyclic aromatic hydrocarbons (PAHs) on soils of nearby residences, playgrounds, and daycare yard. The PAHs are another group of compounds possessing harmful effects and having the potential for dispersal from this site. Some of these compounds are semi-volatile; others sorb to soil particles. When soil particles are dispersed as dust, humans may be exposed via inhalation or through direct contact with dust deposits. The tent structure used during the 2002 removal at this site adequately prevented dust dispersal and provided the basis of our public assurance that PAHs had not contaminated the adjacent child care center property. We would like to be able to provide a similar level of public health assurance during the proposed underpass project. Although an enclosed tent structure provides optimal conditions for air quality management, other contractors specializing in MGP remediation in Wisconsin have had success with surfactants or foams for dust and odor control. The placement of plastic sheeting may be sufficient under many circumstances but has the shortcoming of being labor intensive. Also, we have seen elsewhere that plastic is prone to failure when it is needed most, namely during high winds and heavy rains. Once one corner anchor of the plastic sheets fails in wind, the rest follows. The time and labor required to place the sheet each morning and evening, as well as during the day when needed, should be cost-balanced against the more effective and less labor-intensive foam or surfactant alternatives.
Potential effects to the aquifer used by the Marshfield Municipal Water Utility. Much of the coal tar contaminants in and near the underpass site were removed in 2002. Additional contaminants will be removed during the underpass construction. However, previous study (Dames & Moore, 2000) suggests that after this completed and scheduled removal of MGP wastes, coal tars below 25 feet deep and a soil and groundwater plume of MGP wastes will remain in the neighboring area. Concerns have been raised by a hydrogeological consultant for the city (Janzen, 2002), that these remaining contaminants will threaten the sole aquifer for the Marshfield municipal water supply. According to published water quality results (WDNR 2002), MGP-related VOCs are not currently a health threat in the Marshfield water supply. The incomplete removal of MGP waste prior to commencing the underpass construction may inhibit future remediation needed to protect groundwater. DHFS agrees that because this plume is incompletely characterized, the potential threat to the Marshfield municipal aquifer is an unanswered question that should be monitored. In addition, city officials should discuss contingencies for alternative or treated water sources should the aquifer eventually become unsafe.
Potential exposure related to the underpass lift station. The underpass plans call for the installation of a lift or pumping station in the underdrain system beneath the underpass. The pumping station, as described, will consist of a concrete-walled man hole, normally used to collect storm water, that will also have a pump in the bottom to lift collected groundwater to the sanitary sewer for discharge. The highway underdrain system will be shunted to this man hole for the collection and discharge of contaminated groundwater. There is an unknown potential for organic contaminants in the groundwater collected at the pumping station to volatilize and release contaminants to air. The potential for these releases depends upon both the concentration of individual compounds in collected groundwater and the vapor pressure (potential to volatilize) of individual compounds. Exposure to volatile contaminants at this source could be brief and intermittent, such as to people working or passing near the lift station. Exposure could also be chronic, where volatiles in storm water might enter homes downstream of the lift station via dry P-traps in basement drains. At this time it is not possible to predict a health threat from this source without knowing the concentration of volatile contaminants in groundwater collected at the lift station, as well as knowing design details of the lift station.
Public outreach. Past community involvement activities related to this project have demonstrated strong local public interest. DHFS recommends outreach designed to inform the public of the environmental health effects of the proposed work. It has been our experience that information provided well in advance of the construction start date, along with a meeting for public discussion, is essential in the public's acceptance of the project. The information provided should include a project overview, contaminants of concern, the effects of noise and dust, truck routes, and expected project dates. In the case of the Peach Avenue underpass, outreach should emphasize outcomes of improved public safety, such as better emergency vehicle access and traffic flow. Residents should also be given telephone numbers for key people within the project should they have questions or need to report problems.
The daycare center located adjacent to the Columbia Propane property presents obvious concerns that children and adults at this facility will be affected by the planned remediation of the Marshfield former MGP. Hazards associated with the MGP remediation include the potential for inhalation exposure to VOCs and the associated possibility of respiratory distress, especially in asthmatic children. PAHs sorbed to soil dust may be released to air during soil removal, and may be deposited on surfaces throughout the daycare facility and surrounding playgrounds. The daycare center should be considered to lie within the air impact zone and possibly the health and safety exclusion zone for some phases of this work. Therefore, temporary relocation of the daycare center during the MGP remediation is recommended. In addition, efforts should be made to avoid the deposition of PAH-containing particles on or around the daycare center. Part of the MGP site remedy should include monitoring for PAHs and plans to remove PAHs from indoor or outdoor surfaces should they be detected at unsafe concentrations.
Dames & Moore Group Company. Final Report, Supplemental Site Investigation, and Evaluation of Remedial Alternatives for the Peach Avenue Former MGP Site, Marshfield, Wisconsin. Proj. no. 41384-019-133. June 2, 2000.
Jansen, John, Aquifer Science & Technology. July 3, 2002 letter to Joseph Pacovsky, Marshfield Electric & Water Dept regarding potential effects of Peach Street MGP site on regional aquifer.
RMT Inc. Laboratory Analysis Reports and Summaries. WI Dept. Transportation no. 1623-09-74. July 30, 2002.
RMT Inc. Amendment to Materials Handling Plan. WI Dept. Transportation no. 1623-09-74. July 30, 2002.
Thiboldeaux, R. Public Health Consultation for Columbia Propane, Marshfield, Wood County, Wisconsin. WI Dept. Health and Family Services, under cooperative agreement with the Agency for Toxic Substances and Disease Registry. July 6, 2002.
Thiboldeaux, R., and Nehls-Lowe, H. Interim Guidance on Air Management at Former Manufactured Gas Plant Sites. January 25, 2002 Memorandum to Mark Giesfeldt, Bureau of Remediation and Redevelopment, Wisconsin Department of Natural Resources.
Wisconsin Department of Natural Resources. 2002. Drinking Water System Database.
Available:
http://www.dnr.state.wi.us/org/water/dwg/swap/index.htm 
Robert Thiboldeaux, Ph.D.
Toxicologist
Health Hazard Evaluation Unit
Bureau of Environmental Health
Division of Public Health
Wisconsin Department of Health and Family Services.
This public health consultation for the Peach Avenue Railroad Underpass investigation was prepared by the Wisconsin Department of Health and Family Services under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the Public Health Consultation was begun.
Gail D. Godfrey
Technical Project Officer, S.P.S., SAAB, DHAC
The Division of Health Assessment and Consultation, ATSDR, has reviewed this Public Health Consultation and concurs with the findings.
Lisa C. Hayes
for Chief, State Program Section, DHAC, ATSDR
Table 1. Selected hydrocarbons detected in soil beneath Peach Avenue in proposed excavation area, August 1998 survey.1
1 RMT
Inc. Laboratory Analysis Reports and Summaries. July 30, 2002.
a Sample location: Soil boring SB-4A, middle of present Peach Avenue
near buried structure removed by NiSource (fig. 1).
bUSEPA, Region III Risk-based concentration, transfer from soil to
air. This value illustrates the most probable exposure route for the contaminants
listed.
cUSEPA cancer classification.
Figure 1. Site of proposed Peach Avenue Underpass and vicinity, Marshfield, Wisconsin.
