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Superfund Alternative Site For Illinois
LA SALLE COUNTY
NAPLATE
Congressional District # 11
OTTAWA TOWNSHIP FLAT GLASS SITE
EPA ID# ILD005468616Last Updated: December, 2007
Site Description
The Ottawa Township Flat Glass site ("the site"), also known as the "Libby Owens Ford Plant 5 & 7" site, is located in Naplate, LaSalle County, Illinois. The 228-acre site consists of a glass manufacturing facility ("Plant #7" - (currently inactive) and "Plant #5") located on the north side of the Illinois River plus former silica sand quarries, wastewater disposal areas, and a 56-acre undeveloped parcel of land. It also includes additional former silica quarries and wastewater disposal areas across from the facility on the south side of the river.
The manufacturing plant has been making flat glass products since about 1907. Arsenic trioxide was a minor ingredient in the manufacturing process from 1907 until 1970 when its use was discontinued. The final step in the manufacturing process involved grinding and polishing cast glass with fine silica sand and water. The process generated a waste slurry containing mostly sand, water, and glass particles (containing arsenic) which was discharged into the former quarries for settling of solids and discharge of overflow water into the Illinois River. The slurried waste in the settling areas contains appreciable levels of arsenic and is a source of arsenic contamination in local area groundwater as well as being a direct contact or ingestion threat to human and ecological receptors.
Pilkington North America (“PNA”) has owned and operated the glass manufacturing facility since 1986.
Site Responsibility
The site is being addressed through federal, state, and potentially responsible party actions.Threats and Contaminants
Arsenic is the primary contaminant of concern at the site. It is a poison in high doses and a potential human carcinogen through prolonged exposure to much lower amounts, although it may also be an essential micro-nutrient. People or animals that come into contact with arsenic-contaminated soil or that drink arsenic-contaminated water could be at risk, depending on duration and arsenic exposure levels as well as other factors.
U.S. EPA has divided the site into four distinctive parts ("operable units") for ease of investigating and addressing site contamination and potential health risks. These include residential soils, sediments (in the Illinois River), groundwater and source areas north of the river, and groundwater and source areas south of the river. Elevated levels of arsenic were found in the yards of two residences in Naplate near the glass plant, prompting a look at all yards within the village. The settling areas are located adjacent to the Illinois River, causing a concern that river sediment may have been contaminated with arsenic. Arsenic is found at very high levels in the settling areas and in the shallow groundwater aquifer beneath the settling areas, but it has not impacted Naplate's water supply (derived from a separate aquifer) based on results of historic sampling efforts by the village.
Very high levels of arsenic in residential yards could be an immediate and/or long-term threat to human health through ingestion, inhalation, or dermal absorption. Arsenic contamination in river sediment could impact ecological receptors. Arsenic in the settling areas could be an immediate and/or long-term threat to human health and the environment through ingestion, inhalation, or dermal contact. The arsenic-contaminated groundwater is a potential threat to human health through ingestion should the contaminated water be used for potable purposes.
Cleanup Progress
Illinois EPA initially managed site investigations from the early 1980s until it referred the site to U.S. EPA in the late 1990s. U.S. EPA reached an agreement with PNA in September 2001 whereby the site would be handled as if it were listed on the Superfund National Priorities List but would not have to go through the listing process. U.S. EPA and PNA signed an Administrative Order on Consent ("AOC") under which PNA would conduct a remedial investigation ("RI") and feasibility study ("FS") at the site under U.S. EPA oversight. Remedial investigation activities are underway to determine the nature and extent of (arsenic) contamination in area groundwater, soil, and sediment.
Residential Soils
PNA conducted soil sampling in Naplate residential areas in late 2002 and discovered elevated levels of arsenic in shallow (0 to 6 inches) and deep (greater than 12 inches) sampling points in two lots (417 and 419 22nd Ave.) located close to the factory. It was later determined that settling area fill material had been removed from the facility and used to fill in low spots on the lots so that a home could be built on one of them. PNA, under U.S. EPA oversight, began a time-critical removal action at the two yards in December 2003, excavating arsenic-impacted soil above about 20-40 milligrams per kilogram ("parts per million" or "ppm") and disposing of the impacted soil in an off-site landfill. While this work was being done the affected residents were temporarily relocated to a local hotel. After sampling the edges and bottoms of the excavations to confirm that all impacted soils had been removed, PNA placed clean soil backfill into the excavations and reseeded the lots. The removal action was completed in July 2004. One of the affected residences (417 22nd Ave.) was determined to have high levels of arsenic (dust) within the home and PNA performed an interior cleanup action in 2006 to reduce the interior arsenic levels to safe levels.
PNA also expanded the residential sampling program in 2003 to include additional testing at residences located very near the area of the two impacted properties. The residential soil sampling program was expanded again in Fall 2005 to cover most or all of the homes or lots in the village. Sampling results were tabulated and then evaluated in a risk assessment in the summer of 2007. Generally, sampling results did not indicate that settling area fill material had been placed on other village lots and that no immediate health threats were present.
Sediment
PNA took sediment samples from areas along the site in the Illinois River in 2001 and 2002 to test for arsenic levels. Results are being evaluated with respect to ecological and human health risk with results due in late 2007. Arsenic levels appeared to be mostly at or below naturally-occurring levels in Illinois.
Source Areas and Groundwater
PNA installed a number of groundwater monitoring wells in 2002-04 in and around the site and has sampled nearby private wells to determine the nature and extent of groundwater contamination beneath the site. Results indicate that there are two groundwater aquifers of immediate concern below the site. The upper aquifer, the St. Peter Sandstone, is a regional unconfined aquifer that has been impacted by arsenic contamination from the site. The lower aquifer, the New Richmond Sandstone, has not been found to have been impacted by arsenic contamination. Between the two aquifers lies the Shakopee Dolomite, a 150-200 foot thick aquitard that forms an effective barrier between the St. Peter Sandstone and New Richmond Sandstone. Arsenic levels in the St. Peter Sandstone range from a few parts per billion ("ppb") at the edges of the contaminant plume to several ppm in the center, about 400 times higher than the maximum contaminant level for arsenic (10 ppb) under the Safe Drinking Water Act. The St. Peter Sandstone, however, is not used for potable purposes in the site area. Also, the Village of Naplate public water supply well draws water from the deeper New Richmond Sandstone aquifer and thus is not at risk of arsenic contamination.
PNA collected soil samples on the facility property and results indicate that elevated levels of arsenic are in the settling areas, primarily the former quarries and waste disposal areas where the polishing slurry was discharged. These areas act as sources of arsenic contamination in the upper aquifer. A human health and ecological risk assessment is being prepared to evaluate arsenic impacts with results due in early 2008. Future work will likely consist of gathering data to design soil covers (or “caps”) to place over the source areas that would help prevent further leaching of arsenic into the groundwater, because the volume of source material may be too great to dig up and move to an off-site landfill.
Future Work
PNA will prepare RI reports for each of the four operable units by early to mid 2008 and a FS report for each shortly thereafter. The FS reports will examine cleanup methods for arsenic contamination as appropriate based on the human health and ecological risk assessment results to be presented in the RI reports. However, we will also examine other early action options to address the arsenic in soil and groundwater as appropriate.
Property Reuse
The 56-acre undeveloped parcel that is considered part of the site has been sampled and shown to be not impacted by arsenic on the surface. Thus, the property likely is eligible for reuse, although we project that groundwater-use restrictions may have to be placed on the land to be protective of human health and the environment because arsenic is found in the groundwater beneath the site.
The interior of the impacted residence at 417 22nd Ave. has been cleaned of arsenic residue and is available for reuse.