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Sydney Mine Sludge Ponds

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Pond toward center of Sydney Mine Sludge Ponds site.

Additional Resources
Site Summary Profile
EPA ID: FLD000648055
Location: Brandon, Hillsborough County, FL
Lat/Long: 27.929160, -082.209160
Congressional District: 12
NPL Status: Proposed: 06/10/86; Final: 10/04/89
Affected Media: Ground water
Cleanup Status: Construction Complete – physical cleanup activities have been completed
Human Exposure Under Control: Yes
Groundwater Migration Under Control: Yes
Sitewide Ready for Anticipated Use: No
Site Reuse/Redevelopment: Site reuse plans under developmentpotential for commercial land uses
Site Manager: Shelby Johnston (johnston.shelby@epa.gov)


Current Site Status

The Sydney Mine Sludge Ponds site includes an area mined for phosphate ore from the 1930s through the 1950s, and later used as a liquid waste disposal facility until 1981. EPA placed the site on the National Priorities List (NPL) in 1989 because of contaminated soil, sediment and ground water resulting from waste disposal practices. EPA, the Florida Department of Environmental Protection (FDEP) and the site’s potentially responsible parties (PRPs) have investigated site conditions and taken steps to clean up the site in order to protect people and the environment from contamination. Site contamination does not currently threaten people living and working near the site. By monitoring ground water and undertaking Five-Year Reviews, EPA, FDEP and the site’s PRPs continue to protect residents and the environment from site contamination.

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Site Location and Background

The 9.5-acre site is located in a rural area south of Florida State Road 60 in Hillsborough County, Florida, 15 miles southeast of downtown Tampa. The nearest communities include Brandon, several miles west of the site, and Dover, several miles north of the site. The site is a former liquid waste disposal facility wholly contained within a larger, 1,700-acre former mining area. The site is currently a fenced open field. The surrounding phosphate mine is also fenced.

Mining for phosphate ore took place on site from the 1930s through the 1950s. Starting in late 1973, Hillsborough County leased a small portion of the site property and operated a liquid waste disposal facility until 1981. The facility accepted approximately 16 million gallons of liquid waste, including sludge, grease trappings and cutting oil for disposal. In 1989, EPA listed the site on the NPL.  

The property owner recently sold the site to an investment group that expects to build an alternative energy park on the site. The facility will convert algae into fuel.

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Threats and Contaminants

Site investigations identified contamination in soil, sediment and ground water that could potentially harm people in the area. The contamination resulted from past waste disposal practices at the site. Contaminants of concern identified in ground water include volatile organic compounds (VOCs) such as benzene.

Contaminants migrated below ground into the Hawthorn Aquifer, the principal local drinking water source. Contaminated ground water also spread a few hundred feet beyond the site boundary. However, it is wholly contained within the mining area. People living in the area are located far from the site and the contaminated ground water. PRPs removed contaminated soil and sediment in the mid-1980s. Site PRPs monitor the ground water at the site twice annually.

An institutional control in the form of a restrictive covenant prevents the use of ground water at the site. The restrictive covenant also prohibits the use of the site for any residential purpose.

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Investigation and Cleanup Responsibility / Oversight

PRPs lead site investigation and cleanup activities, with oversight provided by EPA and FDEP.

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Site Cleanup Plan

In 1989, EPA issued a cleanup plan (a Record of Decision, or ROD) for the site. The plan included the following activities:

In 1991, EPA issued an Explanation of Significant Differences requiring the cleanup of VOC-contaminated ground water that spread into the upper portion of the deeper Bone Valley Water-Bearing Unit.

Summaries of site cleanup approaches are also available online in key site cleanup documents, including the ROD.

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Cleanup Progress

PRPs began a voluntary cleanup of the site in 1984. The PRPs constructed a below-ground barrier wall around the ponds, dug up and incinerated pit contents, and constructed a ground water pump-and-treat system in the surficial aquifer. After discovering additional contamination, PRPs excavated and air-dried the contaminants. The PRPs dug up and incinerated twelve thousand cubic yards of contaminated soil from the sludge ponds in the mid-1980s.

In the early 1990s, site PRPs modified the ground water pump-and-treat system to improve its performance. At EPA's request, the PRPs installed additional recovery wells in the intermediate aquifer system.

In late 1997, EPA assessed whether bioremediation, or the use of living organisms to break down contaminants, would be a viable option for the site's surficial and intermediate aquifers. PRPs decommissioned the ground water pump-and-treat system during late 2001 and early 2002. Natural attenuation of remaining ground water contamination is ongoing. The PRPs monitor site ground water semi-annually. Levels of benzene in ground water remain above federal and state drinking water standards.

Summaries of site cleanup approaches are also available online in key site cleanup documents, including the ROD.

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Enforcement Activities

EPA negotiated legal agreements with site PRPs to investigate and clean up the site. The PRPs continue to fund site cleanup, monitoring and oversight activities.

The ROD and Five-Year Reviews online provide information on specific legal agreements for the site.

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Community Involvement

EPA has worked with the community and its state partner to develop a long-term cleanup plan for the site, reflecting the Agency’s commitment to safe, healthy communities and environmental protection. Community engagement and public outreach are core components of EPA program activities.

EPA has conducted a range of community involvement activities to solicit community input and to make sure the public remains informed about site activities throughout the cleanup process. Outreach efforts have included public notices and interviews.

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Future Work

Long-term ground water monitoring is ongoing.

EPA completed the last Five-Year Review in 2011 and plans to complete the next Five-Year Review in 2016.

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Additional Information

EPA keeps additional site documents and information in a site information repository at the location below. EPA also posts site documents, when available, on EPA’s CERCLIS Site Profile page. For documents not available on the website, please contact the Region 4 Freedom of Information Office.

Site Repository

Tampa-Hillsborough Public Library
619 Vonderburg Drive
Brandon, FL 33511

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