Superfund Information Systems: Site Profile

Superfund Site:

SOUTH CAVALCADE STREET
HOUSTON, TX

Cleanup Activities

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Background

The 66-acre South Cavalcade site is located in Houston, Texas. A former wood-treating plant operated on site from 1910 to 1962. A coal tar distillation plant also operated on site from 1944 to 1962. These activities contaminated soil and groundwater with volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and metal salts such as arsenic, chromium, copper, lead, and zinc. Following cleanup, operation and maintenance activities and groundwater monitoring are ongoing.

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What Has Been Done to Clean Up the Site?

The site is being addressed through federal, state and potentially responsible party (PRP) actions.

The EPA is required by Statute to conduct a Site review every five years (Five-Year Review) to ensure that the remedy continues to be protective of human health and the environment.  The most recent review concluded that response actions at the site are in accordance with the remedy selected by EPA and that the remedy continues to be protective of human health and the environment in the short term. Continued protectiveness of the remedy requires implementation of institutional controls to prohibit use of off-site contaminated groundwater.

Annual inspections will continue to be conducted to evaluate the integrity of the condition of the containment caps and identify necessary actions to be taken. In addition, annual evaluations will be conducted to ensure that land and ground water use at and in the vicinity of the Site has not changed and to verify the continued absence of complete exposure pathways for the Site ground water.

 

A wood-treating plant operated at the site from 1910 until 1962. Wood preservatives used at the site included creosote and various metallic salts. The wood-treating process area was located on the southern portion of the site, along Collingsworth Street. Koppers Company, Inc. (Koppers), now known as Beazer, operated the wood-treating facility from 1940 until its closure in 1962. Koppers operated a coal tar distillation plant on the southeastern portion of the site from about 1944 until 1962. 

The Site was brought to the attention of the EPA by the Texas Department of Water Resources in 1984. The Site was added to the final National Priorities List (NPL) on June 10, 1986. Extensive steps have been taken by the EPA since then to ensure protectiveness of human health and the environment, which include, site investigation, sampling, evaluation of the sampling results, evaluation of the remedial alternatives, design of the remedy, construction of remedy which includes construction of concrete caps for soil and construction of treatment system for ground water, ongoing ground water monitoring, and ongoing evaluation of the remedy. At least once every five years, as required by statute, a formal review is conducted to determine the effectiveness of the remedy.

A wood-treating plant operated at the site from 1910 until 1962. Wood preservatives used at the site included creosote and various metallic salts. The wood-treating process area was located on the southern portion of the site, along Collingsworth Street. Koppers Company, Inc. (Koppers), now known as Beazer, operated the wood-treating facility from 1940 until its closure in 1962. Koppers operated a coal tar distillation plant on the southeastern portion of the site from about 1944 until 1962. 

The Site was brought to the attention of the EPA by the Texas Department of Water Resources in 1984. The Site was added to the final National Priorities List (NPL) on June 10, 1986. Extensive steps have been taken by the EPA since then to ensure protectiveness of human health and the environment, which include, site investigation, sampling, evaluation of the sampling results, evaluation of the remedial alternatives, design of the remedy, construction of remedy which includes construction of concrete caps for soil and construction of treatment system for ground water, ongoing ground water monitoring, and ongoing evaluation of the remedy. At least once every five years, as required by statute, a formal review is conducted to determine the effectiveness of the remedy.

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What Is the Current Site Status?

EPA split the cleanup into two approaches to manage and prioritize soil and groundwater activities.

Soil: The long-term remedy included soil flushing and washing. After a pilot study demonstrated that the remedy would not reduce contaminants to meet cleanup goals, EPA updated the remedy to include a reinforced concrete cap. Construction of the remedy finished in 2000. Operation and maintenance activities are ongoing.

Groundwater: The remedy implemented for contaminated ground water involved extracting the ground water and treating it on-site. The contaminated ground water was extracted and treated from 1996 to 2006 and creosote was recovered. Since 2006, creosote has been recovered via manual pumping from the collection wells.  Remedial alternatives for the groundwater were evaluated and the remedy selected in September 2014 was to establish Technical Impracticability (TI) Zones for the groundwater contaminated areas.  Monitoring of the groundwater is continuing in these areas to ensure the groundwater contamination remains stable and is not migrating outside the TI Zone.

EPA has conducted four five-year reviews of the remedy at the Site. These reviews ensure that the remedies put in place protect public health and the environment, and function as intended by site decision documents. The most recent fourth five-year review that was completed in august 2017 concluded that response actions for the soil remedy are in accordance with the remedy selected by EPA and that the remedy continues to be protective of human health and the environment in the short term. The five-year review identified that the following actions must be taken for the remedy to be protective over the long term:

  • Evaluate background arsenic levels and the arsenic levels in the different Technical Impracticability (TI) Zone Boundary wells in comparison to the groundwater criteria and determine the impact of this on the TI Zone Boundary.
  • Delineate the groundwater plume adjacent to OW-14 and P-05 and expand and verify the TI Zone Boundary as appropriate.
  • Complete the implementation of Institutional Controls (ICs) for soils and groundwater once the TI Zone Boundary has been expanded and verified.  The Consent Decree (CD) Amendment with the Potentially Responsible Party (PRP) and the Administrative Order on Consent (AOC) with the current property owners needs to be updated to reflect the expanded TI Zone Boundary.
  • Evaluate the seepage of groundwater into the City of Houston storm sewer within the TI Zone to mitigate the seepage of any Dense Non-Aqueous Phase Liquid (DNAPL) into the storm sewer. Once the actions to be taken to address the seepage are identified, the Consent Decree (CD) Amendment needs to be updated.
  • Annual inspection of the capped area is to be conducted consistently on an annual basis and the capped areas need to be caulked and maintained to prevent storm water seepage into the underlying areas.

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Activity and Use Limitations

At this site, activity and use limitations that EPA calls institutional controls are in place. Institutional controls play an important role in site remedies because they reduce exposure to contamination by limiting land or resource use. They also guide human behavior. For instance, zoning restrictions prevent land uses – such as residential uses – that are not consistent with the level of cleanup.

For more background, see Institutional Controls.

Institutional Controls at this Site will be implemented to prevent potential exposure to the contaminated ground water by restricting access to and use of the contaminated water. ICs (i.e., deed restrictions, or restrictive covenants) provide notice to property owners that contaminated water from the Shallow and Intermediate Zones should not be used for any purpose i.e., for drinking or non-drinking water uses

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Sampling and Monitoring

Beazer continues to conduct quarterly groundwater monitoring to  determine the nature and extent of the plume and plume trends and to confirm the Technical Impracticability Boundary as specified in the Record of Decision Amendment #2, dated September 24, 2014.

 

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