Superfund Information Systems: Site Profile

Superfund Site:

TAR CREEK (OTTAWA COUNTY)
OTTAWA COUNTY, OK

Health & Environment

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What Are the Risks at the Site?

Operable Unit 2 – Residential Areas

OU2 focuses only on residential exposure scenarios with emphasis on young children. The risk assessment identified lead as the only Site-related chemical of concern, and identified oral ingestion as the only significant exposure route or pathway. An exposure route or pathway is the way in which contaminants may enter a human being (e. g. inhalation, oral ingestion, and absorption through the skin). Cadmium and zinc are also Site-related chemicals, but the concentrations in the different media (soil, air, drinking water, etc.) for cadmium or zinc were not high enough to exceed acceptable exposure levels.

The elevated concentrations of lead in soil found at many residences at the Site pose a significant health risk to young children living at those residences (or to those children who may live at those residences in the future). Young children (six-years old and younger) who now play (or children six-years-old and younger who may play in the future) in the residential areas on the Site may be exposed to lead through incidental ingestion of lead contaminated soil during normal hand-to-mouth activity during play, and this lead may pose an imminent and substantial endangerment to the health of such children. In addition, lead contaminated soil may be tracked from residential yard soil into the homes of children where it may be ingested during play or at mealtime, and this lead may pose an imminent and substantial endangerment to the health of such children.

The risk assessment identified lead-contaminated soil as the medium which posed the greatest threat to human health on the Site. The EPA selected, a lead remediation goal of 500 parts lead per million parts soil (ppm) for protection of the child resident.

 

Operable Unit 4 – Source Material

The OU4 Remedial action objectives (RAOs) consist of medium-specific or location-specific goals for protecting human health and the environment. The table presents the RAOs and the remediation goals for source material, soil, and ground water at the Site. It outlines the risks identified and provides the basis for evaluating the cleanup options.

Medium

Summary of Remedial Action Objectives

Remediation Goals

Source Material, transition zone soil, and soil which underlies source material

 

Prevent adolescents from coming in direct contact, through the ingestion and inhalation exposure pathways, with lead-contaminated source material where lead concentrations exceed 500 ppm.  The purpose of this objective is to reduce the central estimate of blood lead concentration in adults (i.e., the mature adolescents in question) that have been exposed to source materials to a level that ensures that the 95th percentile fetal blood lead concentration in their offspring does not exceed 10 µg/dl.  This objective will also be protective for children who live on-site in the event they come in direct contact with the source material through the ingestion and inhalation exposure pathways.

 

Prevent terrestrial fauna from coming in direct or indirect contact, through the ingestion exposure pathway, with

cadmium-, lead-, or zinc-contaminated source materials and soils  where cadmium, lead, and zinc concentrations exceed their respective remediation goals of 10.0 mg/kg, 500 mg/kg, and 1100 mg/kg.  By indirect contact EPA means contact with these contaminants via ingestion of plants grown in contaminated source materials and soil.

 

 

General Tactics:

To meet the above remedial action objectives for source material, the remedy selected in this ROD calls for excavation of source materials to native soils with confirmation samples to ensure the remediation goals are met.    The selected remedy calls for a minimal footprint of source material and maximum unrestricted use of Site land.

 

Adolescents:

500 ppm lead in source material in transition zone soil, and in the soil which underlies source material.

 

 

 

Terrestrial Fauna:

 

10.0 mg/kg cadmium, 500 mg/kg lead and 1100 mg/kg zinc in source material, smelter waste, in transition zone soil, and in the soil which underlies source material.

 

 

 

 

Source Material, transition zone soil, and soil which underlies source material

 

Prevent riparian biota including waterfowl from coming into contact, through the ingestion exposure pathway, with unacceptable concentrations of lead, cadmium, and zinc in surface water and sediment by eliminating all discharge of cadmium, lead, and zinc from source materials to surface water.

Zero discharge of cadmium, lead, zinc from source materials to surface water.  [By zero discharge EPA means discharge concentration levels that would be consistent with the concentration levels that would be expected from soil that has background concentrations of these chemicals.]

Soils

 

Prevent children from direct contact, through the ingestion and inhalation exposure, with lead-contaminated soil where soil lead concentrations exceed 500 ppm.  [The purpose of this objective is to limit exposure to soil lead levels such that a typical (a hypothetical) child or group of similarly exposed children living on site would have an estimated risk of no more than 5% exceeding 10 µg/dL blood lead level.]

 

General Tactics:

To meet the above remedial action objective, the remedy selected in this ROD calls for excavation of residential yard soil up to a maximum depth of 12 inches or until soil concentrations no longer equal or exceed 500 ppm, whichever calls for less soil to be excavated.

 

Prevent terrestrial fauna from coming in direct or indirect contact, through the ingestion exposure pathway, with cadmium-, lead-, or zinc-contaminated soil where cadmium, lead, and zinc concentrations exceed their respective remediation goals of 10.0 mg/kg, 500 mg/kg, and 1100 mg/kg.    By indirect contact EPA means contact with these contaminants via ingestion of plants grown in contaminated soil.

 

General Tactics:

To meet the above remedial action objective, the remedy selected in this ROD calls for excavation of visible source materials down to native soils with confirmation samples of the soil taken to ensure that remediation goals are met.

 

Children:

500 ppm lead in soil

(See OU2 Record of Decision for Tar Creek Residential Areas)

 

 

 

 

 

 

 

 

 

 

Terrestrial fauna:

 

10.0 mg/kg cadmium, 500 mg/kg lead and 1100 mg/kg zinc, in transition zone soil, and in soil underlying source material.

Ground water

Prevent Site residents from the ingestion of water from private wells that contains lead in concentrations exceeding the National Primary Drinking Water Standards.

 

General Tactics:

To meet the above remedial action objective, the remedy will include an alternative water source for those residences affected.

 

0.015 mg/L lead at the water tap

 

 

OU5 – Surface Water and Sediments      Record of Decision – future date to be determined

As this time, there is insufficient information to determine the potential human health risks related to surface water and sediment exposure.  EPA Regions 6 and 7 are working closely with the 3 states (Oklahoma, Missouri, Kansas), nineTribes (Quapaw Nation, Peoria Tribe, Ottawa Tribe, Miami Tribe, Eastern Shawnee Tribe, Modoc Tribe, Wyandotte Nation, Seneca-Cayuga Nation, and Cherokee Nation), and the community to develop and complete a human health risk assessment, characterization report, and feasibility study. This OU5 effort includes 7 watersheds covering approximately 437 square miles and 119 river miles within Oklahoma, Kansas, Missouri, and 9 tribal areas.

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Contaminant Information

View a full list of contaminants of concern for this site.

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Performance Measures

EPA uses performance measures to track environmental results at Superfund sites. If you have any questions or concerns about the measures at this site, please contact the site team members listed under Site Contacts.

Read more about Superfund Remedial Performance Measures.

Performance
Measure
Status at this
Superfund Site
What does this mean?
Human Exposure Under Control No Yes means assessments indicate that across the entire site:
  1. There are currently no unacceptable human exposure pathways; and
  2. EPA has determined the site is under control for human exposure.

No means an unsafe level of contamination has been detected at the site and a reasonable expectation exists that people could be exposed.

Insufficient data means that, due to uncertainty regarding exposures, one cannot draw conclusions as to whether human exposures are controlled, typically because:
  1. Response to the contamination has not begun; or
  2. The response has begun, but it has not yet generated information sufficiently reliable to evaluate whether there are currently any unacceptable human exposure pathways at the site.
Groundwater Migration Under Control Insufficient Data

Yes means EPA reviewed all information on known and reasonably expected groundwater contamination. EPA concluded the migration of contaminated groundwater is stabilized and there is no unacceptable discharge to surface water. EPA will conduct monitoring to confirm that affected groundwater remains in the original area of contamination.

No means EPA has reviewed all information on known and reasonably expected groundwater contamination, and the migration of contaminated groundwater is not stabilized.

Insufficient data means that due to uncertainty regarding contaminated groundwater migration, EPA cannot draw conclusions as to whether the migration of contaminated groundwater is stabilized.

Construction Complete No

Yes means the physical construction of the cleanup is complete for the entire site.

No means either physical construction is not complete or actions are still needed to address contamination.

Sitewide Ready for Anticipated Use No Yes means:
  1. All cleanup goals affecting current and reasonably anticipated future land uses of the entire site have been achieved, so there are no unacceptable risks;
  2. All required land-use restrictions or other controls have been put in place; and
  3. The site has achieved Construction Complete status.

No means that one or more of these three criteria have not been met. However, a site listed as no may still have redevelopment occurring on portions of the site and may be eligible for additional redevelopment.

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