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Technical Assistance Services for Communities West Lake Landfill Superfund Site Fact Sheet #4 – June 2014

Introduction This fact sheet provides information about the history and status of monitoring for gaseous and airborne contaminants at the West Lake Landfill Superfund site in Bridgeton, Missouri. Background West Lake Landfill is located in the St. Louis metropolitan area on the east side of the Missouri River. The 200-acre area is about one mile north of the Interstate 70/270 interchange and four miles west of Lambert-St. Louis International Airport. Limestone quarrying on site from 1939 until 1988 left behind two quarry pits. Beginning in the early 1950s, operators used parts of the quarried areas as a landfill for municipal, industrial and construction waste. Landfill operations ceased in 2005. EPA divided the site into two areas, or operable units (OUs), for cleanup. OU1 addresses radiologically contaminated areas (Area 1 and Area 2). OU2 addresses other landfill areas, including the Bridgeton Sanitary Landfill. The remainder of this fact sheet focuses on OU1. It also provides some information about odors and air monitoring associated with the ongoing Bridgeton Landfill subsurface smoldering event (SSE). Cleanup EPA selected the cleanup plan for OU1 – radiologically contaminated areas – in 2008. EPA selected the remedy in a decision document called a Record of Decision, or ROD. The remedy included covering the landfill, monitoring ground water, 1

U.S. Environmental Protection Agency Technical Assistance Services for Communities 2014

controlling surface water runoff and monitoring landfill gas. The ROD also called for land and resource use controls, long-term surveillance and maintenance. Since completion of the ROD, EPA has led additional site investigations and directed OU1 Respondents (the potentially responsible party group) to do so as well. TASC Fact Sheet #2 discusses additional ground water sampling at the site. TASC Fact Sheet #3 summarizes a Supplemental Feasibility Study (SFS) completed in December 2011. The SFS Report discusses two alternatives to the ROD-selected remedy, which involve the excavation and removal of radiologically contaminated materials. What’s Next? If EPA decides to revise the remedy in the site’s ROD, the Agency will issue an additional decision document called a ROD Amendment. If EPA issues a ROD Amendment, there will be a public comment period before the Agency finalizes it. Technical Assistance Services for Communities (TASC) The Technical Assistance Services for Communities (TASC) contract provides EPA-funded technical support for communities living near hazardous waste sites. This support can include information assistance, community education and technical expertise. TASC is currently providing technical support to communities affected by the West Lake Landfill through the West Lake Landfill Community Advisory Group.


Air Monitoring Cause of Landfill Odors

There has been periodic air monitoring for gaseous and airborne contaminants at the site. Soil vapor sampling and fugitive dust sampling between 1995 and 1997 were part of the site’s remedial investigation. The Missouri Department of Natural Resources (MDNR) began collecting air samples in August 2012 due to the SSE at Bridgeton Landfill. EPA is planning for on- and off-site air monitoring before, during and after an isolation barrier is put in place to prevent the SSE in Bridgeton Landfill from spreading to OU1. Radon Gas, Landfill Gas and Fugitive Dust Report, West Lake Landfill Areas 1 & 2 (1996) A consultant for the OU1 Respondents measured radon concentrations and sampled soil vapor, surface soil and fugitive dust in Areas 1 and 2, and surrounding areas as part of the site’s remedial investigation. The report came out in November 1996. Radon Collection of radon samples took place at five locations on a wet, rainy day in October 1995 and on a dry day in December 1995. Radon concentrations ranged from 6.7 picocuries of radon per liter of air (pCi/L) to 6,163 pCi/L during wet conditions, and from 3.8 pCi/L to 279.6 pCi/L during dry conditions. [In outdoor air, radon is expected to disperse and become diluted. In indoor air, radon concentrations above 4 pCi/L should be remedied.] Soil Vapor Contractors collected soil vapor samples at 18 soil boring locations in Area 1 and 31 locations in Area 2. They analyzed the samples for methane gas. Methane gas was present in Area 1 borings above its Lower Explosive Limit (LEL) of 5 percent in all but two locations. LEL is the lowest concentration of a gas in air that can result in an explosion if an ignition source is present. The highest methane reading in Area 1 was 40 percent. Methane gas was present above its LEL in 17 Area 2 borings. The highest methane reading in Area 2 was 30 percent. Based on the concentrations measured, a contingency plan was developed to address methane concentrations during drilling. 2

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Some common landfill gases have very unpleasant odors at very low concentrations. Even when concentrations are low enough to not cause health effects from chemical exposure, the odor, itself, can make some people feel sick. Individual sensitivity to odors varies depending on factors such as age, gender, experience and genetics. Odorcausing landfill gases include hydrogen sulfide (rotten egg smell) and methyl mercaptan (rotten cabbage smell). Other typical odor-causing compounds emitted from landfills are reduced nitrogen compounds, including ammonia and triethylamine, and, to a lesser extent, reduced phosphorous compounds, volatile organic compounds (VOCs) and fatty acids. Hydrogen sulfide, in particular, is an important indicator of decomposing wastes typically found in landfills, as it can be smelled at one of the lowest concentrations of any compound emitted from landfills.

Soil Contractors collected soil samples at 2 feet and 2 inches below ground surface to check for the probability of airborne contamination. The report identified only priority pollutant metals as a nonradiological fugitive dust concern. No other nonradiological air emission concerns were identified. Contractors collected soil samples at about 2 feet below ground surface at five locations in Area 1 and 10 locations in Area 2. They analyzed the samples for volatile and semi-volatile organic compounds of concern. Three VOCs – xylenes, 1,4dichlorobenzene and acetone – as well as three semi-volatile organic compounds (SVOCs) – di-noctyphthalate, bis(2-ethylhexyl) phthalate and fluoranthene – were identified in soil samples. Little to no non-methane VOCs were present near the landfill surface beneath Areas 1 and 2. Therefore, potential release of VOCs and SVOCs to the atmosphere did not appear to be a significant issue at the site.


Contractors collected soil samples at a depth of 2 inches at five locations in Area 1 and 10 locations in Area 2. They analyzed the samples for polychlorinated biphenyls (PCBs) and pesticides, priority pollutant metals, and total petroleum hydrocarbons. PCBs were found in soil samples from three borings (one in Area 1, two in Area 2). Pesticides were detected in soil samples from four Area 2 borings. Metals are naturally occurring and were present in all surface samples. However, several soil samples contained metals at concentrations higher than other surface soil samples by one or two orders of magnitude. In some samples, arsenic, beryllium, cadmium, copper, lead, mercury, nickel, selenium and zinc concentrations exceeded their respective, site-specific background concentration. Petroleum hydrocarbons, mostly characteristic of motor oil, were also present in about half the surface soil samples. Fugitive Dust Sampling Contractors sampled fugitive dust upwind and downwind of one non-vegetated radiological “hot spot” in Area 1 and one in Area 2 on April 11, 1996. Wind was blowing from the south at 14 miles per hour or greater. The temperature ranged between 78 and 82 degrees Fahrenheit. There had been no rainfall for three or more days. Dust samples were analyzed for: Isotopic uranium Chromium Isotopic thorium Copper Radium 226 Lead Arsenic Selenium Beryllium Zinc Cadmium Upwind and downwind sampling in Areas 1 and 2 detected uranium-238 and thorium-232. Concentrations varied from 0.00005 to 0.00270 pCi/L. Sampling did not find any uranium-235 decay series constituents or priority pollutant metals in any of the fugitive dust samples. Dust samples collected upwind and downwind of the two radiological hot spots contained radionuclides at concentrations below the occupational health (worker) exposure limit criteria for industrial smoke stack emissions. 3

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For More Information EPA West Lake Landfill website: http://www.epa.gov/region07/cleanup/west_lake _landfill/index.htm Missouri Department of Natural Resources (MDNR) West Lake Landfill website: http://dnr.mo.gov/env/hwp/fedfac/westlakelandfi ll-ffs.htm MDNR Bridgeton Sanitary Landfill website: http://www.dnr.mo.gov/Bridgeton Republic Services Bridgeton Sanitary Landfill website: http://www.bridgetonlandfill.com Rock Road Industries, Inc. West Lake Landfill website: http://westlakelandfill.com/

The report states that “all of the fugitive dust data collected to date have been collected from within the interior of radiological Areas 1 and 2. No data pertaining to fugitive dust concentrations along the perimeter of Areas 1 and 2 have been collected and no conclusions can be reached. The sampling program was designed and performed to evaluate fugitive dust generation under a worst case scenario and not offsite migration and exposure potential.” Remedial Investigation Report (2000) A contractor evaluated the amount of radon gas passing into the air at 54 locations in Areas 1 and 2 and the former Ford Property. Measurements at two locations in Area 1 and two locations in Area 2 were above the 20 picocuries per square meter per second (pCi/m2s) standard for the average amount of radon gas moving into air from a uranium mill tailings pile (see text box). The Remedial Investigation Report states that once the radon gas National Emission Standards for Disposal of Uranium Mill Tailings Radon-222 emissions to the ambient air from a uranium mill tailings pile that is no longer operational shall not exceed more than 20 picocuries per square meter per second of Radon222.


is emitted from the surface of the landfill, it will be immediately diluted and dispersed in the atmosphere. Air Monitoring at Bridgeton Landfill Since April 2013, MDNR personel have continuously monitored hydrogen sulfide, sulfur dioxide, carbon monoxide and total VOCs at three locations. They also conduct routine, twice-daily surveys of hydrogen sulfide, benzene and odor levels around the perimeter of the Bridgeton Landfill. Gamma radiation measurements are also reported. Reports are available at: http://www.dnr.mo.gov/bridgeton/BridgetonSanitar yLandfillReports.htm. The Missouri Department of Health and Senior Services (DHSS) posts health analyses of MDNR air sampling results at: http://www.health.mo.gov/living/environment/bridg eton. The analyses indicate that no detected compound concentrations would be expected to result in acute health effects. DHSS is working with the Agency for Toxic Substances and Disease Registry (ATSDR) to assess chronic health effects. Assessment results are forthcoming. Daily, weekly and additional air sampling reports are also available from Republic Services, owner of Bridgeton Landfill, at: http://www.bridgetonlandfill.com/content.aspx?pag e=AirSampling. Bridgeton Sanitary Landfill Radiological Air Sampling Report (2013) Throughout June 2013, DHSS staff visited Bridgeton Landfill to collect particulate air samples to be analyzed for alpha and beta activity. DHSS concluded that alpha and beta activities around Bridgeton Landfill during June 2013 were indistinguishable from natural background levels. OU1 Respondent Air Monitoring Since late 2013, during the Gamma Cone Penetration Test (GCPT), OU1 respondents sampled air for alpha and beta activity and thorium at two fixed locations in Area 1 of OU1 and one non-fixed location. The non-fixed location is placed down wind of a specific work area. On-site air monitoring will expand in preparation for the 4

U.S. Environmental Protection Agency Technical Assistance Services for Communities 2014

construction of the isolation barrier. The preconstruction work plan outlines air monitoring stations monitored for radioactive particulates, radon gas, VOCs, and gamma radiation at the perimeter of OU1 Areas 1 and 2, and at multiple onsite locations. 2014 EPA Air Monitoring Plans EPA’s West Lake Landfill Update (April 28, 2014) describes the current plan for off-site air monitoring that will take place before, during and after the isolation barrier is put in place. EPA Region 7 will operate off-site monitoring stations in Bridgeton at the Robertson Fire Protection District on Taussig Road, the Pattonville Fire Department Administration Building on St. Charles Rock Road, and Spanish Village Park on Spanish Village Drive. EPA Region 7 will also operate air monitors at Pattonville Fire Department #2 on McKelvey Road in Hazelwood and at St. Charles Fire Department #2 on South Main Street in St. Charles. Figure 1 shows the monitoring locations. Off-site air monitoring will include particulate matter, alpha, beta and gamma radiation and related constituents, and VOCs. EPA expects monitoring to be partially operational by mid-May 2014 and fully operational shortly thereafter.

West Lake Landfill Superfund Site

Figure 1: Proposed locations of EPA’s off-site air monitoring stations

TASC Fact Sheet #4 - Airborne Contaminants - 06 09 2014  
TASC Fact Sheet #4 - Airborne Contaminants - 06 09 2014  
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