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The Washington State Department of Health (DOH) has prepared this health consultation at the request of the Washington State Department of Ecology (Ecology) to evaluate the potential public health hazards posed by contaminants in the vicinity of the proposed Trent Avenue (SR 290) realignment located in Spokane, Spokane County, Washington. This health consultation will consider both current and future land use scenarios. DOH prepares health consultations under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR).

The Washington Department of Transportation (DOT) has proposed two alternatives to realign Trent Avenue so that it no longer crosses the Spokane River. The proposal would require approximately 0.75 miles of new road, some of which would cover suspected areas of environmental contamination located along the banks of the Spokane River. These areas were identified in a limited assessment released by DOT in February 1996. These areas include the former Spokane Gas Manufacturing (CERCLIS NO. WAD981762990), the former American Tar Company (CERCLIS NO. WAD981766272), a former rail yard, the former Spokane Inland Empire Railroad power substation, Freedom Marine Manufacturing and the former St. Louis Brass and Iron Foundry. (1). Figure 1 shows the approximate location of each of these sites.

Brown Building Materials (BBM) now occupies the site of the former Spokane Gas and American Tar companies, and is located directly beneath the Hamilton Street Extension on the south bank of the Spokane River. The Spokane Gas Manufacturing company occupied approximately 1.3 acres along the river and functioned as a coal gasification facility from 1905-1948, producing the fuel "town gas" as the primary product. Coal tar was produced as a byproduct and sold to the American Tar Company, located adjacent and directly to the south. Light oils were also produced as a byproduct and may have been disposed on-site. Other wastes likely disposed on-site include ash and clinkers (metallic, granular debris probably composed of silicon, calcium, and aluminum oxides.) Wastewater was discharged directly to the Spokane River and probably contained ammonia, various petroleum hydrocarbons and polycyclic aromatic hydrocarbons (PAHs). (2) ,(3)

Historic analysis of coal gasification plants indicate that tar-water emulsion leaks occurred from all stages of production. In addition, some plants suffered from high water contamination of the tar byproduct reducing its value and perhaps increasing on-site dumping. Historic use of fill along the south bank of the river has increased the acreage of the area and changed the original location of the south bank of the river. This is consistent with other plants that reportedly used brick from demolished process structures as fill. (3),(4) Fill has also been used more recently to cover spots of surface tar. (1),(5) Figure 2 gives the former locations of buildings owned and operated by the Spokane Gas and American Tar companies.

The former rail yard is located east of the BBM property along Riverside Avenue. Various maintenance and warehousing activities were conducted at the site by the Burlington Northern Santa Fe Railroad. Soil windrows remain in this area from previous cleanup conducted by the City of Spokane along Riverside Avenue. The former Spokane Inland Empire Railroad power substation property is located west of Erie Street and is currently owned by BBM. This area was identified as a power substation in 1910, but was later occupied by Western Light Metals. Freedom Marine Manufacturing is a fiberglass boat manufacturer located on Front Avenue west of Erie Street and the BBM property. The former St. Louis Brass and Iron Foundry operated from the 1930s through the late 1960s on Erie Street just north of Freedom Marine on the south bank of the Spokane River.(5)

Site Visit

On January 23, 1998, Robert Duff and Cindy Gleason (DOH) accompanied Mark Fuchs (Ecology) on a site visit of the areas of concern outlined above. Windrowed soil was noted to be present along Riverside Avenue in the area of the former rail yard (see Appendix A for site photos). The area of the former Spokane Gas and American Tar companies was noted to be occupied by BBM with a considerable amount of salvage construction materials extending along the south bank of the Spokane River from Erie Street east to the former train tunnels. Two transient dwellings were visible at the end of Riverside Avenue located on a basalt bluff east of the BBM property. It is not known whether or not these dwellings are currently occupied or how frequently they are used.

Access to the river on the BBM property was limited by vegetation with one footpath to the water noted. Salvage materials were arranged in an orderly fashion some of which were within several feet of the river bank including a stack of creosote treated rail road ties. Monitoring wells were also noted on the site.

Environmental Investigations

A May 1995 Screening Site Inspection Report prepared for the United States Environmental Protection Agency (EPA) included sediment and surface water sampling in the Spokane River. One surface water sample with duplicate was taken near the south bank of the river, adjacent to the site, approximately 60 meters downstream of the Hamilton Street Extension. One sediment sample was taken downstream of the site on the north bank of the river. Background sediment and surface water samples were taken upstream of the site. Sediment and surface water samples were analyzed for inorganics (metals), polychlorinated biphenyls (PCB) and semi-volatile organic compounds (SVOC), and polynuclear aromatic hydrocarbons (PAH).(2)

Further and more extensive sampling of soil and groundwater was conducted in September 1997 in response to the areas of concern outlined in the DOT limited assessment. Soil sampling in the former rail yard area along Riverside Avenue included 10 test pit soil samples and 2 surface soil grab samples taken from the windrowed soil stockpile. Soil samples were also taken from 47 borings located primarily in the vicinity of the former Spokane Gas Works as well as other areas of concern noted above. At the time of this sampling event, visible contamination was still present at the terminus of some of these borings, with observations of free phase hydrocarbons and tar-like substances at various depths. Groundwater samples were taken from six of these soil borings in the vicinity of the former Spokane Gas Works, using a temporary well point. Both soil and groundwater samples were analyzed for metals, PCB, SVOC, PAH and total petroleum hydrocarbons (TPH).(2) The location of these soil borings are shown in Figure 2.

The most recent investigation included installation of 8 monitoring wells (five shallow and three deep) located around the perimeter of the former Spokane Gas Company (see Figure 2). Groundwater samples taken from these wells in December 1997 were analyzed for PAH and cyanide. One soil boring sample was analyzed for volatile organic chemicals (VOC), SVOC, TPH, cyanide and metals. A single sediment sample was collected from a location in the Spokane River immediately adjacent to the site, while a background sediment sample was taken at an upstream location. One surface water sample was also taken at each of these locations. Sediment and surface water samples were analyzed for PAH and cyanide. (6)

The maximum detected levels of the contaminants of concern are given in Table 1 below. Contaminants of concern are chosen based on comparison of levels detected in each medium with respective screening values for that medium. Contaminants of concern do not necessarily represent a public health hazard, but signify the need for further evaluation. The screening values used in this consultation are provided by ATSDR.

Table 1.

Maximum Levels of Contaminants of Concern at the former Spokane Gas and American Tar Companies
Sediment Surface Water Surface Soil * Sub-surface Soil ** Groundwater
CONTAMINANT ppm ppb ppm ppm ppb
PAH 0.42 1.64 4.3 129,036 9866
TPH NA NA 1840 396,000 206,000
dibenzofuran ND ND NA 800 77.1
carbazole ND ND NA 2270 262
bis-2-ethylhexylphthalate ND ND NA ND 27
n-nitrosodiphenylamine ND ND NA 179 53.6
arsenic 9.3 2.6 12.3 59 28
lead 59 4.4 568 799 + 1.5

* = Surface soil samples were taken only in the vicinity of the former rail yard area.
** = Sub-surface soil sample maximums found at various depths in the vicinity of the former Spokane Gas Company.
+ = This maximum detection of lead was located in the former rail yard area. The maximum lead level found on the former Spokane Gas Company site is 427 ppm.

ND = Not detected
NA = Not analyzed.

The data given in Table 1 indicate that a substantial source of coal gasification byproducts exist at significant depths below ground surface in the vicinity of the former Spokane Gas and American Tar companies. The primary soil contaminants are TPH and PAH. Surface soil sampling data are limited to test pits and grab samples taken in the former rail yard area. They do not include areas where highly contaminated soil boring samples were taken. Arsenic was also detected at elevated levels in sub-surface soil and moderately high lead levels were found in both surface and sub-surface soil.

Groundwater analyses indicate very high levels of TPH and PAH. However, these data were generated exclusively from well sampling points established in soil borings SB-1 through SB-37 that are suspect for suspended solid or phase separated product contamination. Subsequent analysis of groundwater samples taken from 8 monitoring wells showed no detection of PAH, but were not sampled for TPH or SVOC. It should be noted that these monitoring wells were not located in the previously identified areas of high soil and groundwater contamination, but were located so as to define the perimeter of this contamination.

Surface water and sediment samples taken from the Spokane River, indicate minimal PAH contamination. However, only one sediment sample and two surface water samples were taken adjacent to the site. A second sediment sample taken downstream and on the opposite bank of the river, detected trace levels of PAH. Surface water and sediment were not analyzed for TPH.

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