Hollingsworth Solderless Terminal

• Site Profile
• Administrative Record Index (PDF): OU1 (34 pp., 909K), ESD (1 pp., 34K)
• Additional Site Documents including Five Year Reviews, Records of Decisions (ROD) and Explanation of Significant Differences (ESD).
• For documents not available on the website, please contact the Region 4 Freedom of Information Office (http://www.epa.gov/region4/foiapgs/submit.htm).

Site Background:

The Hollingsworth Solderless Terminal Company (HSTC) Site is located on 3.5 acres of an industrial/residential area of Ft. Lauderdale, FL. The plant operated from 1968 to 1982 as a solderless terminal manufacturing facility. The manufacturing process included the use of molten salt baths, degreasing parts and electroplating. The wash and process waters, which contained high concentrations of trichloroethylene (TCE), a metal degreaser, and heavy metals, were disposed of in numerous onsite drainfields-, by surface discharges, and in a 100-foot-deep injection well.

Site Responsibility: This site is being addressed through federal actions.

Threats and Contaminants

Groundwater contamination due to the discharge of TCE into the four drainfields, which surrounded the process building, has resulted in a groundwater plume in the immediate vicinity of the site.  Several communities in the vicinity of the site obtain their drinking water from the sole-source Biscayne aquifer.

Cleanup Approach

In 1982 HSTC pumped out the injection well.  After the company filed for bankruptcy, EPA installed and operated a soil vacuum extraction system in one of the former drainfields.  This system was operated for two and a half months, from January through July 1991. 

A groundwater recovery and treatment system was constructed and put into operation in the early 1990s. This system treated contaminated groundwater and re-injected the treated water into the aquifer. Groundwater recovery and treatment ceased in October 1994. Subsequent monitoring of groundwater has shown a consistent upwards trend of groundwater contaminants, well above State of Florida and federal standards. Fieldwork to locate the potential source(s) of groundwater recontamination took place in August 1999. As a result of this work, the former South Drainfield has come to be identified as a previously unrecognized and untreated source of groundwater contamination.

In February 2002, contaminated soil located in the South Drainfield area was removed and disposed of. Soil was excavated to a depth of approximately two feet below the water table. In addition, the septic tank associated with the Western Drainfield was removed and its contents were disposed of.  Sampling of groundwater in the summer of 2002 showed that the site’s shallow well had met the clean-up goals. Intermediate depth wells (50- and 75-foot below ground surface) were found to be above the site’s clean-up goals for certain volatile organic compounds.

In December 2003, subsurface soil samples were recovered for the purpose of determining the subsurface soil’s oxidant demand. Results indicate that the subsurface soil oxidant demand is substantial, increasing the cost of an in-situ chemical oxidation remedy for the remaining contaminated subsurface soil. In March 2004, EPA and FDEP were evaluating pursuing chemical oxidation or enhanced biostimulation as remedies for the remaining areas of subsurface soil contamination. Biostimulation is the addition of an organic substance, such as potassium lactate, which would be metabolized by microorganisms. In the process, contaminants are degraded. End products are innocuous ethene and ethane.

Response Action Status

The results from the first round of potassium lactate injection are mixed.  Field and laboratory analytical results indicate that the reductive dechlorination (contaminant breakdown) process is working and that viable bacteria are present.  However, the operation of one of the recirculation cells, located in the area of the former south drainfield, has resulted in what appears to movement of previously undetected contamination into one of the performance monitoring wells.

A second batch of potassium lactate was injected and re-circulated in mid-2006.  Results of sampling of about two dozen wells in late September 2006 were encouraging.  There appeared to have been a site-wide decrease in contaminant concentrations.  In addition, geochemical and bacteriological indicators were also positive, indicating the right environment for dechlorination.  Groundwater sampling in 2007 showed that two, relatively small areas exist with concentrations considerably above State standards.  An amendment to the 1986 ROD was proposed in May 2008, to permit additional injection of a carbon source, designed to promote the final degradation of these two areas.  The amendment to the 1986 ROD was finalized in November 2008.  As a result of November 2008 sampling, it was recommended that before additional carbon source is added, another round of groundwater data be obtained since all but two wells had fallen to below the State Natural Attenuation Default Criterion for vinyl chloride.  These two wells were only 20 parts per billion above that criterion.  May 2009 groundwater monitoring results indicate rebound of TCE degradation products in a monitoring well near the former South Drain Field.  A design will be underway during the summer of 2009 for additional injection of additional carbon source, in order to insure that contaminant concentrations remain below standards.   

The site’s third Five Year Review Report was concluded in December 2005.  The link to the Report is:  http://www.epa.gov/superfund/sites/fiveyear/f0604003.pdf.

Site Repository
Broward County Public Library, 100 S. Andrews Ave.-Level 5, Ft. Lauderdale FL 33301