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Frequently Asked Questions


MCL = maximum contaminant level

OTFG = Ottawa Township Flat Glass

OUs = Operable Units

PNA = Pilkington North America

ppb = parts per billion

ROD = Record of Decision

Table of Contents

Prepared September 2011


1. What is the difference between the Ottawa Township Flat Glass site and the Ottawa Radiation Areas site? Isn't it all one Superfund site?

The Ottawa Township Flat Glass (OTFG) site and the Ottawa Radiation Areas site are two separate Superfund sites.

The OTFG site concerns arsenic contamination at and around Pilkington North America's (PNA) in Naplate and Ottawa, Illinois. The arsenic comes from waste materials produced by the former owner of the facility until 1970. PNA purchased the site 16 years after the use of arsenic was discontinued and does not use arsenic in any form today. Arsenic in residential soil and river sediment near the site has already been addressed and its present level poses no threat to human health or the environment. The ground water, on the other hand, was contaminated when waste materials containing arsenic seeped to the St. Peter aquifer below the site. This ground water contamination underlies portions of the current property owned by PNA and some properties immediately adjacent to the site. However, the groundwater is not used for potable purposes and there are no unacceptable exposures to arsenic. The EPA project manager for the OTFG site is Nefertiti Simmons.

The Ottawa Radiation Areas site consists of 16 areas polluted by radioactive materials scattered within and outside the City of Ottawa in LaSalle County, Illinois. The pollution came from the Radium Dial Co. (from 1918 to 1936) and Luminous Processes, Inc. (from 1937 to 1978). Building demolition material and soil polluted with radioactive waste were used as fill material in the Ottawa area. The EPA project manager for the Ottawa Radiation Areas site is Denise Boone. For more information, see http://www.epa.gov/region05/cleanup/ottawa/

The remaining questions and answers relate only to the OTFG site.

2. What are Operable Units (OUs) and what are they for the OTFG site? How far along the cleanup process is each of the OUs? Can this be shown on a map?

Ottawa Township Flat Glass site map (PDF) (1pg, 1.73MB) September 2011

An operable unit refers to each of a number of separate activities undertaken as part of a Superfund site cleanup. The EPA divided the OTFG site into four operable units or OUs for ease of investigating and cleaning up the site.

3. Is PNA currently releasing arsenic contamination from their property?

PNA purchased this site 16 years after the use of arsenic in glass making was discontinued. PNA has never used arsenic at this site in any of its processes. PNA owns quarries on the north and south sides of the Illinois River and these quarries are filled with waste materials that contain arsenic from operations that occurred before PNA purchased the site. The quarries which contain the old arsenic waste material seeped into the upper aquifer, thus contaminating the ground water in the St. Peter aquifer.

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Water Concerns

4. Is there any testing of water taking place on an on-going basis at the OTFG site? If so, where and how frequently?

Historically, PNA has taken ground water samples on the site twice a year. PNA also samples the Village of Naplate drinking water supply four times per year. In addition, PNA has implemented a sampling program in the unincorporated area of Ottawa related to the remedial design for providing an alternate water supply for OU3.

5. Is the water safe for brushing my teeth or washing my clothes?

In Naplate, the residents are supplied with municipal water, so there is no reason to be concerned about arsenic in the water. In the unincorporated area of Ottawa, where residents use the ground water to clean themselves and wash their clothes, the levels of arsenic are not high enough to be a concern for these activities. Only five properties closest to the PNA site have had historic levels of arsenic in their water that make it unsafe to drink, but incidental ingestion from bathing does not present an unacceptable risk.

6. Has the EPA changed what it considers "safe" or "tolerable" contamination levels of arsenic in the water since the site was first identified?

Yes. When this project began, in 2001, the standard for arsenic in the ground water was 50 parts per billion (ppb), now the standard is 10 ppb, which is a more protective standard. A ppb is comparable to one penny in 10 million dollars or one drop in an Olympic-sized pool.

7. Are there any wells within the St. Peter Sandstone (upper) aquifer?

In Naplate, all known residential ground water wells have been made inactive and the residents are supplied with municipal water. Within unincorporated Ottawa on the south side of the site there is an area where residences have active wells. PNA is conducting sampling within this area. The five households with residential wells where arsenic has historically been detected have been supplied with bottled water by PNA for over 10 years.

8. Is PNA currently discharging to the quarries? If so, does this pose a danger to the aquifers, the environment and human health?

Former sand quarries located on the south side of the river were used from 1996 until March 2006 as wastewater retention ponds for plant process water, sanitary water, and sand pond leachate. These ponds were operated under a permit issued by the State of Illinois. Although PNA retains a permit to operate the quarries, PNA began discharging to the City of Ottawa's sanitary sewer in 2006. The selected remedy for OU3 consists of rerouting surface water drainage on the PNA property to contain the impacted ground water plume within PNA's property boundaries.

9. Is there concern about storm water runoff contamination entering the sewage system or treatment facility?

No, there is no concern of contaminated storm water entering the sewage system. Although the proposed remedy for OU3 will in fact involve redirecting storm water within the PNA property, it is in order to address containment efforts in the groundwater.

Stratigraphy of the Ottawa-Naplate area showing underground rock layers and aquifers.

Stratigraphy of the Ottawa-Naplate area showing underground rock layers and aquifers. View larger image.

10. Can arsenic contamination from the upper aquifer in the Ottawa area contaminate the lower aquifer where water is drawn from for the community?

It is not likely that the upper (St. Peter) aquifer will contaminate the lower (New Richmond) aquifer because there is a 130 to 150-foot-thick naturally occurring barrier called an aquitard between the two aquifers. This barrier is made up primarily of dolomite and shale and it is extremely difficult for water to pass through it. PNA samples the lower aquifer quarterly and the sampling results show that arsenic has not contaminated the lower aquifer.

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Soil Concerns

11. Are there health concerns for children who play outdoors on the soil? Is there a risk if people consume their garden's vegetables?

EPA found no unhealthy levels of arsenic in residential soil samples, except at two yards where the contaminated soil has already been removed. It was determined that arsenic concentrations in residential soils are within the typical range for north central Illinois soil—i.e, consistent with naturally-occurring conditions. Thus, the EPA decided that no further action would be needed to protect the people's health and the environment within Naplate.

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Human Health Concerns

12. People hunt animals that graze in the area. Is there a risk if their meat is consumed?

A human health risk assessment was conducted to evaluate potential exposures of those who may trespass into the Pilkington site to hunt. The risk assessment determined that there would be no unacceptable risk posed to human health as a result of exposure to soil or sediment at the site. EPA assumed that aquatic, terrestrial and bird species observed at the site could be exposed to contaminants through external direct contact or ingestion of impacted sediment or food. EPA concluded that there is no potential for adverse effects to terrestrial and bird species caused by arsenic in the soil, sediment or surface water at OU 3. However, the risk assessment did not look at wading birds such as herons, egrets and cranes, nor did it evaluate fish-eating gulls, ducks and their nestlings. The environmental risk assessment will be re-examined when the final Record of Decision (ROD) is completed for OU3.

13. What about the fish in the Illinois River?

In 2002, PNA conducted river water toxicity testing on benthic organisms—organisms that live on the bottom of the river—and data showed some chronic effects on the organisms, but not enough to impact the fish in the river.

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Site Reuse

14. What happens after a Superfund site is cleaned up? Can it be put to productive use?

Once sites have been cleaned up, EPA works with communities through an array of tools, partnerships, and activities to help to return these sites to productive uses. These uses can be industrial or commercial, such as factories and shopping malls. Some sites can be used for housing, public works facilities, transportation, and other community infrastructure. Some sites can be for recreational facilities, such as golf courses, parks and ball fields; or for ecological resources, such as wildlife preserves and wetlands. No matter what use is appropriate for a site, the community benefits from restoring the site to productivity, because the area can once again add to the economic, social, and ecological value of the community.

The 56-acre undeveloped parcel that is considered part of the OTFG site has been sampled and shown to be not impacted by arsenic on the surface. Thus, the property likely is eligible for reuse, although EPA projects 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.

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