STATE, COUNTY, AND PCS MONITOR GROUNDWATER

NEAR SWIFT CREEK CHEMICAL COMPLEX AFTER SINKHOLE COLLAPSE 

White Springs - State and local agencies continue to monitor groundwater quality at private and public water supply wells and the Suwannee River after the collapse of a sinkhole under a phosphogypsum stack at the PCS Phosphate Swift Creek Chemical Complex in Hamilton County released some 84 million gallons of process wastewater.

PCS reported the formaiton of the sinkhole to the Florida Department of Enivronmental Protection (DEP) on December 10. The sinkhole provided a conduit to the Floridan aquifer; however, representatives of PCS Phosphate Company report that most of the water has been captured on site by production wells at the Swift Creek Chemical Complex.

PCS as required by DEP has since expanded its internal monitoring well system and installed additional wells on other parts of its property downstream from the sinkhole to check for the presence of pollutants in the aquifers. DEP also directed PCS to begin sampling private drinking water wells to ensure that process wastewater is not affecting those wells located within a two mile radius of the Swift Creek facility. PCS is conducting exploratory geotechnical drilling to determine the size and shape of the cavity to prepare for eventual closure of the sinkhole.

The Hamilton County Board of County Commissioners has retained the services of Lampl Herbert Consultants (LHC), an independent natural resource consulting firm based in Tallahassee, to review reports and data regarding the sinkhole as these come available from the DEP and PCS. LHC will keep the Board up-to-date on events and findings.

Private Wells Tested

State and local agents began testing additional water wells the week of December 21 at the request of residents in the area, according to John Coates, P.E., Chief, Bureau of Mining and Mineals Regulation, DEP. In other responses to the release fo the process wastewater:

•  DEP and the Hamilton County Health Department tested public water supply wells for the Town of White Springs; the wells are located some 10 miles southeast of the PCS Swift Creek Complex.
• Suwannee River Water Management District (SRWMD) and DEP are jointly monitoring water quaility of the Suwannee River to assess potential enivronmental impacts.

To date, seven residents have requested well testing, Coates said. As of December 22, daily samples had not shown any impacts or concerns at the offsite ground water wells or the Suwannee River sites.

Hamilton County residents may request well testing by calling Ron Taylor, Hamilton County Environmental Health Director at (386) 792-1414, extension #227. County and DEP staff will schedule a time to sample and will provide feedback on your well. Here's what to expect if ask if your well is tested:

• Technicians will use a handheld meter to measure the "pH" and the "conductivity" of the water produced at your well. pH refers to the alkalinity or acidity of the water. Conductivity refers to the measurement of the ability of water to conduct electrical current. The results of the meter tests -- when compared with background data from other wells in the general area -- will provide an immediate, preliminary indication as to whether or not the process wastewater from the sinkhole release has reached your well.
• Technicians will also collect water samples that will be sent to state water quality laboratories for a more complete analysis of chemicals that might by found in the process wastewater such as sulfates, chlorides. and metals. DEP and the county health department staff will provide the results of the expedited laboratory analyses as soon as they are available.

DEP will work with PCS to provide an alternative supply of water to citizens if any wells are impacted, according to DEP in its December 13 press release.

The PCS North Florida Mine Complex

PCS or its predecessors have operated mines and producted fertilizer in the Hamilton County area since the 1970s. The December 2009 sinkhole is the second "collapse feature" to occur at the White Springs phosphate mining area. The previous sinkhole formed at the PCS Suwannee River Chemical Complex in 2007 and was repaired by 2008; this facility is located some five miles east of the December 2009 sinkhole. In 2007, process wastewater was not released from ponds at the Suwannee River facility. Sinkhole features frequently occur in Florida in areas underlain by linmestone.

For additional information, please see "Florida's Sinkholes," Florida Geological Survey, Poster No. 11, prepared by Frank Rupert and Steve Spencer in 2004.

http://www.dep.state.fl.us/geology/geologictopics/sinkhole/florida_sinkhole_poster.pdf