FLORIDA DEPARTMENT OF ENVIRONMENTAL PROTECTION

Transcription

1 FLORIDA DEPARTMENT OF ENVIRONMENTAL PROTECTION SOUTH DISTRICT P.O. BOX 2549 FORT MYERS, FL RICK SCOTT GOVERNOR CARLOS LOPEZ-CANTERA LT. GOVERNOR HERSCHEL T. VINYARD JR. SECRETARY June 26, RETURN RECEIPT REQUESTED Robert Taylor Lead Environmental Scientist Maintenance Management-Infrastructure Management Section South Florida Water Management District (SFWMD) 3301 Gun Club Road West Palm Beach, Florida Subject: Collier County WC Limited Phase I & Phase II Environmental Site Assessment (ESA) South Florida Water Management District (SFWMD) Work Order 27 Section 16, Township 52 South, Range 28 East Collier County, Florida URS Job # FDEP BWC Tracking # COM_ Dear Mr. Taylor: The Florida Department of Environmental Protection-South District Office s Compliance Assistance Program (FDEP-SD CAP) Waste Cleanup Program has completed our technical review of the Limited Phase I & Phase II Environmental Site Assessment (ESA) And Geotechnical Evaluation for the. The Environmental Site Assessment generated by URS Corporation, including a Geotechnical Evaluation by Radice, was received by the South District on June 5, 2014 for technical review and evaluation. We have determined that the submittal has addressed the Recognized Environmental Concerns (RECs) associated to the excavation/dredging of soils and bedrock to create an oxbow with a shallow and deep brackish water pool off of the as a habitat for the West Indian Manatee. Please review our Interoffice Memorandum dated June 24, 2014 detailing our technical review of the submittal.

2 Page 2 June 26, 2014 Any questions regarding the Department s technical review of documents associated to the subject areas associated to this project should be directed to Charles A. Masella, Environmental Consultant, at (239) , or Charles.Masella@dep.state.fl.us, South District Waste Cleanup Program-CAP. Whenever possible, please submit any written communication(s) or submittal(s) electronically to our South District general folder at FTM.Tanks.Cleanup@dep.state.fl.us. Please refer to FDEP Project Tracking Identification Number for this site COM_ on all future correspondence with the Department concerning the subject and associated areas. Sincerely, Charles A. Masella, Environmental Consultant Division of Waste Management Waste Cleanup Program/Storage Tank Program South District - Compliance Assistance Program CAM cc: Janet Starnes SFWMD (JStarnes@sfwmd.com) Jennifer Gent- SFWMD (JGent@sfwmd.com) Emily Bauer US FWS (Emily_bauer@fws.gov) Edward Leding URS (Ed.Leding@urs.com) Jamie Sullivan URS (Jamie.Sullivan@urs.com) Jon Iglehart FDEP (Jon.Iglehart@dep.state.fl.us) Albert D. McLaurin FDEP (Albert.McLaurin@dep.state.fl.us) Jennifer Carpenter FDEP (Jennifer.Carpenter@dep.state.fl.us) Charles A. Masella - FDEP (Charles.masella@dep,state.fl.us) Mark A. Sautter FDEP (mark.sautter@dep.state.fl.us) Julie Neurohr FDEP (Julie.Neurohr@dep.state.fl.us)

3 Interoffice Memorandum To: From: File Charles A. Masella Bureau of Waste Cleanup-South District CA&E Date: June 24, 2014 Subject: Collier County WC Limited Phase I & Phase II Environmental Site Assessment (ESA) South Florida Water Management District (SFWMD) Work Order 27 Section 16, Township 52 South, Range 28 East Collier County, Florida URS Job # FDEP BWC Tracking # COM_ The Department s South District Waste Cleanup Program has completed our technical review of the Limited Phase I & Phase II Environmental Site Assessment (ESA) and Geotechnical Evaluation for the with the. The submittal (dated May 29, 2014) was generated by URS Corporation (URS) pursuant to South Florida Water Management District (SFWMD) Work Order #27, and received by the Department for technical review and comment on June 5, The initial investigation was conducted on the project area property along the western bank of the, south of the Port of Islands residential community. The project consists of a that is associated to the Picayune Strand Restoration Project (PSRP). The project consists of the excavation/dredging of soils and bedrock in an effort to create an oxbow with a shallow and deep brackish water pool off of the as a habitat for the West Indian Manatee. URS was tasked to conduct an evaluation of the subject area for contamination by hazardous substances, primarily agrochemicals, petroleum product associated residuals, and metals which might represent a Recognized Environmental Concerns (RECs). The initial Phase I ESA investigated the western bank of the. It was determined that the project site was used to stage materials excavated during the construction of the in the late 1960s. During the interim, native upland vegetation has been established on the eastern portion, with mangrove and other native vegetation taking hold on the lower elevation, western portion of the subject area. Historically, a failed residential and agricultural community was located two plus miles to the north and northeast of the site position. Current agricultural operations exist approximately six plus miles to the northwest. Drainage from these areas, plus assumed direction of surface flow, indicate that these past and present agricultural operations might have posed a potential for impact to the subject area that should be further investigated to determine the current status of the project site through Phase II ESA activities. Printed on recycled paper.

4 FDEP WC Tracking # COM_ Page 2 The Phase II ESA consisted of determination of the spoil materials that were excavated and dredged from the, and deposited on the project location. The assessment was initiated during February 2014 by URS, with water table levels documented at 3.0 to 7.0 feet below grade level. URS representatives advanced ten (10) soil borings, with ten soil samples collected for analysis. Testing consisted of EPA Method 8081A for Organochlorine Pesticides, Florida Residual Petroleum Organic Method (FL-PRO) for Total Recoverable Petroleum Hydrocarbons (TRPHs), Eight (8) Resource Conservation Recovery Act (RCRA) Metals, and the metal Copper. Synthetic Precipitation Leachate Procedure (SPLP) was conducted on selected metals to determine leachability potentials. The analytical results indicate that Organochlorine Pesticides and Total Recoverable Petroleum Hydrocarbons (TRPHs) were below detection limits (bdls). Chromium was reported to be in excess of Florida Administrative Code (F.A.C.) Rule Soil Cleanup Target Levels (SCTLs) for Leachability Based on Freshwater Surface Water Criteria for half the samples tested. The metals Chromium, Copper, and lead were further analyzed by Synthetic Precipitation Leachate Procedure (SPLP) to determine site specific leachability. Those results indicated that all three metals will not leach into the groundwater and surface water at concentrations exceeding SCTLs for the project area. URS reported that the 95% Upper Confidence Level (UCL) for Chromium was calculated at 7.44 milligrams per kilogram (mg/kg), a value that is below the site specific SPLP analysis results. Groundwater samples were collected from two temporary monitoring wells, designated TMW-1 and TMW-2. Testing consisted of EPA Method 8081A for Organochlorine Pesticides, Florida Residual Petroleum Organic Method (FL-PRO) for Total Recoverable Petroleum Hydrocarbons (TRPHs), Eight (8) Resource Conservation Recovery Act (RCRA) Metals, and the metal Copper. In addition, the laboratory was instructed on the Chain of Custody to hold sufficient samples of the 8 RCRA metals and Copper for filtered/unfiltered sampling comparison. The laboratory reported low concentrations of the metals Arsenic, Barium, Chromium, and Lead A concentrations within F.A.C. Chapter Groundwater Cleanup Target Levels (GCTLs). The metal Selenium was detected (and confirmed during a re-analysis) to exceed GCTLs. The organochlorine pesticides and residual petroleum constituents were not detected in the samples. However, Selenium concentrations are indicative of saline background concentrations related to the close proximity of the (salt water wash over events) to the sampling area, and not an indication of contamination that requires remediation. The Geotechnical Evaluation (dated May 2, 2014) included in the URS submittal and generated by Radise determined the existing subsurface conditions to assist in the evaluation and design of the project. Printed on recycled paper.

5 FDEP WC Tracking # COM_ Page 3 The Radise evaluation determined that the project area, a reticulated coastal swamp, consisted of naturally occurring native soil, and wetland ground conditions, covered by stockpiled spoil material excavated from the adjacent during the construction of the. The upper naturally occurring soils are classified as Durban Series type, a poorly drained organic soil overlying sandy marine sediments. The Radise report evaluated the differentiated materials that occur (natural and made depositional) in the project area, and methods of excavation as related to the individual strata that will be encountered during the construction phase of the project. The report also expresses concerns that might occur as related to de-watering in an ecologically sensitive area. The Radise report should be considered when planning the field construction design for the project. Summary: The detection of materials regulated by the Department through Florida Administrative Code (F.A.C.) Rule Soil Cleanup Target Levels (SCTLs), and Groundwater Cleanup Target Levels (GCTLs) appear to be within criteria, it would be logical to assume that the operations involving the excavation/dredging and deposition of spoils might, however unlikely, contain a concentration of a regulated constituent in excess of criteria that could leach or contaminate if conditions were ideal. In considering the three options for disposal of excavated/dredged material included in the URS submittal, the most efficient is Option 1: Spread the Dredged Material in the Project Area. This option, with significantly less transport expense appears not only to be the most cost effective, it is the only option with a guarantee that any possibly impacted soils and/or sediment will not be distributed to pristine areas, or buried at locations within the water table. However, considering our review of the Geotechnical Evaluation, the excavated material should not pose an impact to the environment, both flora and fauna, if employed as material to construct and strengthen the bank or shoreline features of the proposed oxbow channel in the area. As a secondary consideration, Option 3: Relocate to a Nearby District Project would solve a need for soils for other projects, but would include substantial additional transportation cost. The Department would sanction this option, with caveat that no materials are placed below the water table. We would suggest reconsideration of the Option 2: Bury Dredged Material in the Project Area which would require a more extensive soil sampling regiment, likely including additional laboratory analysis to determine the exact concentrations of materials destined for burial in areas that are at or below seasonal water levels. The Radise Geotechnical Evaluation (dated May 2, 2014) and included in the URS submittal, appears to indicate that the water table is elevated in relation to the URS approximation, and this would result in a greater percentage of material, if buried, to be within the water table, or subject to overflow from storm surge. We would assume that the topography is similar for lands south of US Highway 41 east and west of the Faka Union Canal, and similar high water would be encountered in those areas precluding burial of soils.

6 FDEP WC Tracking # COM_ Page 4 In selecting which of the three options may be the most suitable for post excavation/dredging material disposal, the Radise Geotechnical Evaluation (dated May 2, 2014) should be considered by the stakeholder to optimize the use of the material, and reduce costs associated with disposal. Printed on recycled paper.