REILLY TAR & CHEMICAL CORPORATION SITE
ST. LOUIS PARK, HENNEPIN COUNTY, MINNESOTA
Based on the information and data reviewed, the MDH concludes that the Reilly Tar and Chemical Corporation site poses no apparent public health hazard.
At present, local residents use water drawn from some municipal wells which contain low levels of PAHs. Exposure to these compounds may occur via ingestion of and possibly dermal contact with potable water. However, concentrations of PAHs in the water from these wells are monitored to assure that they are below Drinking Water Criteria established in the CD-RAP (see Public Health Implications). As long as the concentrations of PAHs in these wells remain below the Criteria, exposure to them via drinking water use is not of public health concern.
Although local residents may have been exposed to higher concentrations of PAHs in drinking water in the past, neither the concentration of the PAHs nor the duration of exposure can be determined because sampling of municipal wells did not occur prior to 1978. Therefore, it is not possible to evaluate potential health impacts resulting from past use of municipal drinking water.
In 1984, the MDH, in conjunction with the University of Minnesota School of Public Health, evaluated the feasibility of conducting a community-based epidemiologic study to address adverse health outcomes which might be related to the ingestion of contaminated drinking water in St. Louis Park. Following an intensive 18-month evaluation, the MDH concluded that it was very unlikely that any type of epidemiological study would be able to directly address the impact of ingestion of PAH-contaminated water and subsequent cancer development.
On recent site visits it was observed that gullying was occurring on the sides of the hill located in the SW portion of the Site. Erosion of the vegetative cover on the top of the hill was also occurring. This may potentially pose a hazard to persons (for example, children) playing on the hill because these processes have exposed potentially contaminated subsurface soil and demolition debris such as rotted wood, chunks of cement, and bricks. (The hill was formed from visibly contaminated excavated soils and some demolition debris that remained after the razing of the former plant buildings and the construction of the on-Site apartments).
The results of limited sampling efforts have shown that subsurface soils both on- and off-Site are contaminated with Site-related chemicals. These soils (excluding those of the hill in the SW corner of the Site) are considered to be generally inaccessible to people because of the presence of vegetative cover, roadways, buildings, parking lots, etc.
The provisions of the 1986 CD-RAP are continuing to guide the remediation of the Site. Many remedial activities have been completed, and others are on-going. Briefly, remedial activities have included: installation and operation of contaminant source control wells, installation and operation of contaminant gradient control wells, installation and operation of granular activated carbon treatment systems on two municipal wells to remove PAHs, implementation of a comprehensive groundwater monitoring program, closing of multi-aquifer wells that allowed contaminants to migrate to deeper aquifers, excavation and removal of on-Site contaminated soils during past demolition and construction activities, construction of storm water retention ponds to control surface run-off from the Site, and off-Site wetland filling (in the area where waste water discharge occurred during plant operations).
A thorough investigation of the hill in the SW corner of the Site should be carried out. This should include the quantitative determination of any chemical contaminants (for example, PAHs) present in the subsurface and surface soil (0-3"). If it is determined that chemical contaminants are present in the soils and that human contact with them is possible (or occurring), they should be removed in a timely fashion or made inaccessible by appropriate means until remediation is completed.
A thorough investigation of potential chemical contamination of the subsurface and surface soils (0-3") of the remaining portion of the Site should be carried out. At this time, the very limited data that are available show that subsurface soil is contaminated throughout the 80-acre Site. Because the Site is used as a park and housing units are built on the Site, persons may be exposed to Site-related contaminants during activities in which contact with soils are possible (for example, team sport activities, children digging in the soil). In addition, contaminants in the on-Site subsurface soils can migrate downward through the soil and serve as a continuing source of groundwater contamination.
The surface water and sediment of the on-Site stormwater retention pond (Oak Pond) should be sampled for the presence of Site contaminants (for example, PAHs). There were no sampling data found pertaining to the potential contamination of either the water or sediment of this pond. While contact with these media are not expected to be routes of human exposure to Site contaminants, the water and sediments should be sampled for the presence of Site-related contaminants because contamination data for these media are currently lacking.
Certain compounds included under Parts A.1.1 (Carcinogenic PAH), A.1.2 (Other PAH) and A.2 (Extended List of Carcinogenic PAH) of Appendix A of the Remedial Action Plan should be examined with respect to their ability to cause cancer in humans. For example, benzo[k]fluoranthene, which is considered to be a human carcinogen by the National Toxicology Program (32), is not counted as a carcinogenic compound during routine groundwater monitoring. The reason for this is that it is listed under Part A.1.2. of Appendix A, and section D. of the 1986 Consent Decree states that: "For Monitoring purposes, the concentration of Carcinogenic PAH shall be the sum of the concentrations of all compounds listed in Parts A.1.1 and A.2 of Appendix A of the RAP". In addition, there are also chemicals that may be considered to be non-carcinogenic that are listed under Parts A.1.1 and A.2 that will, if present in the groundwater, unnecessarily increase the total reported concentration of Carcinogenic PAH.
All provisions for remediation, monitoring, and reporting of results outlined in the 1986 Consent Decree-Remedial Action Plan for the Site should continue to be carried-out. This is particularly important because implementation of these measures will reduce or prevent further contamination of area groundwater or other environmental media with Site-related contaminants such as PAHs.
Special attention should be paid to provisions of the Consent Decree-Remedial Action Plan which deal with the future development (including construction of buildings, playgrounds, roads, etc.) on Site and in the immediate vicinity of the Site. This will reduce or eliminate the potential for human exposure to chemical contaminants that may be exposed during these activities.
Work on the pilot bioventing system/technology for contaminated soils, sponsored by the EPA SITE team, MPCA, and the City, should continue.
When indicated by public health needs, and as resources permit, MDH, in conjunction with ATSDR will evaluate additional relevant health outcome data and community concerns, if available.
The Minnesota Department of Health and the Agency for Toxic Substances and Disease Registry (ATSDR) will follow the progress of the recommendations outlined above. One way MDH will follow the progress of investigations and remedial activities at the Site will be to review, at the request of the appropriate parties (for example, the Minnesota Pollution Control Agency), reports or progress updates prepared by those carrying out these activities.
The city of St. Louis Park will begin monthly inspections of the hill in the southwest portion of the Reilly Tar & Chemical Corporation site. The inspections will begin in 1992 after the spring snow melt and continue until snow covers the ground. In the event erosion of the hill is observed, the condition will be immediately corrected.
In accordance with the Comprehensive Environmental Response Compensation and Liability Act of 1980 (CERCLA) as amended, the Reilly Tar and Chemical Corporation site has been evaluated for follow-up health activities. Although human exposure to site contaminants is currently occurring via drinking water use, this exposure is not occurring at levels of public health concern. Prior to 1978, exposure to higher concentrations of contaminants may have occurred. However, because extensive environmental groundwater sampling did not occur prior to 1978, it is not possible to evaluate the significance of this past exposure. A community health education effort related to this site was undertaken. The Minnesota Department of Health and the Minnesota Pollution Control Agency have distributed fact sheets and conducted/attended numerous public meetings. Community health education activities are ongoing. This site is not being considered for additional follow-up health activities at this time. However, if data become available suggesting that human exposure to hazardous substances at levels of public health concern is occurring, ATSDR and the Minnesota Department of Health will re-evaluate this site for any additional follow-up health activities.
Robert Roy, Ph.D.
Research Scientist 2 (Toxicologist)
Minnesota Department of Health
Section of Health Risk Assessment
ATSDR Regional Representative:
Denise Jordan-Izaguirre
Regional Services
Office of the Assistant Administrator, ATSDR
ATSDR Technical Project Officer:
Richard R. Kauffman, M.S.
Technical Project Officer
Division of Health Assessment and Consultation
Remedial Programs Branch, ATSDR
This public health assessment was prepared by the Minnesota Department of Health under 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 assessment was begun.
Richard R. Kauffman, M.S.
Technical Project Officer, SPS, RPB, DHAC
The Division of Health Assessment and Consultation, ATSDR, has reviewed this public health assessment, and concurs with its findings.
Robert C. Williams, PE, DEE
Director, DHAC, ATSDR
