From 1904 to 1931, the Barker Chemical Company manufactured a product known as “super phosphate”. In the manufacturing process, phosphate was stripped from low grade, phosphate-rich rock, using sulfuric acid processed on the Site. Sulfuric acid was processed from pyrite and arseno-pyrite imported from Spain and England. The Withlacoochee River served as a barge canal for the import of raw materials such as pyrite and the export of super-phosphate.
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In the early 1900s, sulfuric acid was commonly processed utilizing the lead chamber method. In this method, sulfides, such as copper and iron pyrites, were heated to produce sulfur dioxide, leaving iron and arsenic as a by-product. The sulfur dioxide was then mixed with nitric oxides in lead lined chambers producing sulfuric acid. Sulfuric acid, added to finely ground low grade phosphate-rich rock, would produce super-phosphate, releasing fluorine in the process.
Iron from the burning of sulfides would be the most probable source of the reddish-colored soils at the Site. Arsenic from the burning of sulfides such as arseno-pyrites would be the most probable source of arsenic contamination at the Site. Lead from the lead-lined chambers, leached by sulfuric acid, would be the most probable source of lead contamination at the Site.
In March of 1995, the Florida Department of Environmental Protection (FDEP) became aware of arsenic and lead contaminated soils at the Site. In March and April of 1995, FDEP collected and analyzed soil samples from the Site along with sediment and surface water samples from the Withlacoochee River. In April, May, July and August of 1995 the Florida Department of Health and Rehabilitative Services collected soil samples from residential yards and ground water samples from residential wells in the sub-division. In October of 1995, FDEP submitted a Preliminary Draft Assessment Report to EPA for review.
In December of 1995, EPA’s Emergency Response and Removal Branch (ERRB) performed a removal site evaluation, to determine the full extent of contamination in the residential area. Soils from residential yards, a day care center, the local school, a swimming area and several local businesses were sampled, along with ground water from residential wells. Based on the analytical results, on March 11, 1996, the EPA Waste Management Division Director approved the use of removal funds to undertake a removal action at the Site. A $2,780,000 ceiling was established. The removal action was intended to address contaminated soils in the residential area. On August 27, 1996, a Ceiling Increase to continue removal activities was approved, establishing a Site ceiling of $5,802,000. Removal activities were initially completed on April 14, 1997. During the initial assessments and removal activities, EPA found levels of lead and arsenic in soil as high as 34,000 mg/kg and 640 mg/kg, respectively.
Since EPA's Removal Action, FDEP has continued investigating the Site. In July of 2003, samples were taken by FDEP and EPA’s Environmental Services Division. Based on an FDEP request, EPA ERRB and START conducted a review of the previous action and the recent FDEP sampling to determine possible additional areas of surficial soil contamination. After a review of the proposed sampling plan by FDEP, EPA, FDEP and START conducted a removal assessment at the Site on December 21, 2003, including the collection of 37 surface and sub-surface soil samples at 5 residential properties, not previously addressed. At the request of FDEP, sediment samples were also taken on the banks of the Withlacochee River.
Analytical results indicated the presence of elevated levels of lead and arsenic, above removal action criteria, in residential surficial soils at the Site. Levels as high as 630 mg/kg and 6,800 mg/kg for arsenic and lead, respectively were found. Based on the removal site evaluation, on August 9, 2004, the EPA Region 4 Waste Managment Division Director approved the use of removal funds to undertake a removal action at the Site. A $1,122,000 Site ceiling was established.
Clean-up activities at this Site have continued since September of 2004.