SUPPLEMENTAL HEALTH CONSULTATION
ECONOMY PRODUCTS COMPANY SITE SHENANDOAH, PAGE COUNTY, IOWA
STATEMENT OF ISSUES AND BACKGROUND
Region VII Environmental Protection Agency (EPA) provided the Iowa Department of Public Health, Toxic Substances Evaluation Program (IDPH-TSEP) with a draft copy of the Engineering Evaluation/Cost Analysis (EE/CA) dated April 1998 and recent sampling reports (October/November 1997 and March 1998) for the Economy Products Company site in Shenandoah, Iowa . Region VII EPA asked TSEP staff to review data and information provided to determine whether recent data suggests that human exposure to hazardous substances at levels of public health concern is occurring, or has occurred in the past and to provide comments on the EE/CA. This health consultation focuses on the most recent data and information provided by Region VII EPA. The Health Consultation for the Economy Products Company dated April 7, 1998 provides a review of historical data and information (including maps and figures) and is provided in Appendix A.
The Economy Products Company (EPC) site is a 1-acre property located in Shenandoah, Page County, Iowa. The surrounding area is a mixture of commercial and residential properties. The east and south side of the site is bordered by the Earl May Seed and Nursery Company (EMSNC), and to the north and west, by 8th Avenue and Southwest Road, respectively. EPC operated as an agricultural chemical firm that formulated various pesticides, including organochlorine (OC) pesticides, from 1961 to 1973. Some of the pesticides are now banned or have been subjected to restricted use regulations (i.e., aldrin, chlordane, tetrachlorodiphenylethane (DDD), dichlorodiphenyltrichloroethane (DDT), dieldrin, endrin, heptachlor, lindane, and toxaphene).
On May 10, 1973, a fire destroyed the chemical warehouse together with the main packaging area and an adjacent building. An office building situated on the southwest corner of the property was the only structure remaining. In 1974, EMSNC purchased the EPC property and currently uses the building for office space. The remainder of the site is composed of soil/grass plots, which are segregated by concrete sidewalks. The closest private residence is approximately 40 feet south of the site.
It was thought that, pesticide residues were dispersed throughout the site and surrounding areas during the fire. Following the fire, most of the recoverable hazardous chemical materials/residues were removed and disposed of at off-site locations by the Iowa National Guard. The bulk of the materials were buried in the Stennett limestone quarry in Stennett, Iowa, and the remaining debris and rubble were disposed of at the Shenandoah Municipal Landfill. The area where the fire occurred was covered with a one-foot clay cap.
Additional environmental samples were collected during October-November 1997 and March 1998. As part of the EE/CA, samples were collected in October-November 1997 and analyzed in the field with a mobile gas chromatograph. A percentage of samples was sent to the EPA regional laboratory for confirmatory analysis. The areal and vertical extent of pesticide contamination was established during the sampling event and included surface (approximately 0-4 inches) and subsurface soil (at varying depths up to 14 feet), dust and groundwater samples. A total of fifty seven surface and twenty one subsurface soil samples were collected onsite, on the adjacent railroad property and in the nearby residential areas. Six dust samples were also collected from the floors and walls of the north and south on-site metal buildings. Nine groundwater samples were collected. Additionally, thirteen soil samples at multiple depths were collected onsite and analyzed for polychlorinated dibenzodioxins/ polychlorinated dibenzofurans (PCDDs/PCDFs).
Pesticides were detected in surface and subsurface soil samples at concentrations greater than compound specific risk-based removal action levels (RALs). The highest detected concentrations were located on the Economy Products property. Table 1 presents the highest detected concentrations exceeding RALs and their respective RALs. Several pesticides were detected in dust samples at levels below compound specific risk-based RALs. In March 1998, confirmatory soil sampling was conducted on surface and subsurface soils. Samples were collected from the on-site and adjacent railroad property. The results confirmed the mobile laboratory results and supported the established boundaries of contamination.
Nine groundwater samples were collected in October/November 1997. Six of the groundwater samples did not have detectable levels of pesticide. Three of the groundwater samples had detectable levels of pesticide. Lindane (38.0 ppb) and dieldrin (0.082 ppb) were detected in a shallow on-site piezometer (P-5) located in the area of the fire. Dieldrin was also detected in two shallow groundwater samples on the railroad property (0.9 ppb in piezometer #1(P-1) and 0.068 ppb in monitoring well #6 (MW-6)). The federal maximum contaminant level (MCL) for lindane is 0.2 ppb. An MCL for dieldrin has not been established.
Additionally, thirteen subsurface soil samples were collected onsite and analyzed for PCDDs/PCDFs. Total 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents were calculated. Four samples contained total 2,3,7,8-TCDD equivalents greater than 1.0 ppb (residential comparison value) but less than 10.0 ppb (industrial comparison value). The highest concentration of total 2,3,7,8-TCDD equivalents detected was 5.84 ppb. All four samples were located on-site near the location of the fire.