In August I reported on abandoned mine lands in Missouri, which are inventoried and reclaimed by the Land Reclamation Program of the Missouri Department of Natural Resources, working with the Office of Surface Mining Reclamation and Enforcement of the Department of the Interior. These lands constitute the largest inventory of contaminated lands in Missouri. The most seriously contaminated, however, are Missouri’s Superfund sites, and the most widely dispersed are leaking underground storage tanks. These are each monitored by different government programs, and the programs that monitor them are distinct from the program that monitors toxic releases. I will report on these latter three types of pollution in the next several posts.

In 1980, the U.S. Congress enacted the Comprehensive Environmental Response, Compensation, and Liability Act, designed to clean up sites badly contaminated with hazardous substances. This program is what is known by the common name of Superfund. Contaminated sites are proposed to EPA for inclusion on the National Priorities List (NPL). Using a number of criteria, the EPA assesses each site and assigns a hazard score to each, and those above the designated threshold are assigned to the NPL for clean up. The NPL sites are what we commonly call Superfund sites. They tend to be the largest, most badly contaminated hazardous waste sites, the worst of the worst.

The number of NPL sites in Missouri and several other states are given in the table below. Some of the sites are mine sites, but others represent contamination by industrial or agricultural chemicals and pollutants.

Table 1: Number of National Priorities List Sites in Selected States:

North Dakota has the fewest in the nation. (With all the petroleum activity up there, would you want to bet on whether that will change?) New Jersey has the most. (EPA 2017a) You can see that the number of sites in the selected states has changed only slightly.

Figure 1. Source: EPA 2017a.

Figure 1 at right shows the location of the sites in Missouri. Yellow diamonds are sites on the NPL. Green circles are sites that were on the list, but have been removed. Red squares indicate sites that have been proposed for addition to the list. The sites cluster around St. Louis, Kansas City, Springfield, Joplin, and the Lead Belt mining region. The yellow, orange, and pink denote different EPA administrative regions. Missouri is in Region 7.

In some cases, the contamination cannot be made safe. Rather, it must be removed and placed in a structure designed to prevent the contamination from escaping for a very long time.

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Figure 2. Weldon Spring Disposal Cell. Source: Department of Energy.

The NPL site in Weldon Spring is a good example. A large chemical plant operated in Weldon Spring that produced explosives during World War II and that processed uranium for 11 years at mid-century. A large volume of land became contaminated with toxins, including radioactive materials. This land was excavated and put in a large pit/mound surrounded by impervious materials and covered with rock (a “disposal cell”) (See Figure 2). Residual contamination remains, which is handled through “administrative means,” (keeping the public out), and the NPL program will have to continue to monitor the site for a very long time. (EPA 2017b, DOE date unknown)

Nationwide, 1,785 sites are listed as active on the NPL. Of these, 394 are classified as deleted (meaning the site has been remediated to the point that it is no longer of interest to the NPL program), 1,342 are classified as on the final list (meaning they are awaiting remediation, in the process of remediation, and/or under continuing monitoring after remediation), and 40 are listed as proposed (meaning they are under consideration for addition to the list). (EPA 2017a)

Sources:

U.S. Department of Energy. Weldon Spring Interpretive Brochure. Printing date unknown. Downloaded 10/28/17 from https://www.lm.doe.gov/LMSites.aspx?id=1399.

U.S. Department of Energy. 2017. Weldon Spring Site (photo). Downloaded 10/28/2017 from https://www.lm.doe.gov/Weldon/Interpretive_Center/Presentation_Topics.pdf.

U.S. Environmental Protection Agency. 2017a. Search for Superfund Sites Where You Live.. At this webpage, each NPL site is listed, and links are provided to additional information about the site. In addition, maps of NPL sites can be created, and spreadsheets can be downloaded. Viewed online at https://www.epa.gov/superfund/search-superfund-sites-where-you-live#advanced.

U.S. Environmental Protection Agency. 2017b. Superfund Site: Weldon Spring Quarry/Plant/Pits (USDOE/ARMY), St. Charles, MO. Viewed online 2017-10-18 at https://cumulis.epa.gov/supercpad/SiteProfiles/index.cfm?fuseaction=second.cleanup&id=0701753.