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HomeMy Public PortalAbout20120823Exhibits (2).pdfTerracon Consultants, Inc. 2201 Rowland Avenue Savannah, Georgia 31404 P (912) 629 4000 F (912) 629 4001 terracon.com/savannah July 26, 2012 Georgia Environmental Protection Division Underground Storage Tank Management Program 4244 International Parkway, Suite 4 Atlanta, Georgia 30354 Attn: Mr. Kelly B. Adams P: (404) 362 2597 E: kelly.adams@dnr.state.ga.us Re: No Further Action Confirmation Request Van Horn Property 76 Van Horn Street Tybee Island, Chatham County, Georgia EPD Facility ID: 4250113*1 Terracon Project No.: ES127048 Dear Mr. Adams: Terracon Consultants, Inc. (Terracon) is submitting this letter and supporting documentation on behalf of the City of Tybee Island, Georgia in reference to the Van Horn Site (EPD Facility ID No. 4250113*1). The purpose of this letter is to request confirmation that the current No Further Action Status is still applicable given the results of recent groundwater and soil sampling at the site. Our recent groundwater and soil sampling was completed as part of a pre-development Limited Site Investigation (LSI) of the site for a new Tybee Island Police Department building. SITE SUMMARY 1.0 The subject site is located at what is now known as 78 and 80 Van Horne Street, Tybee Island, Chatham County, Georgia. The subject site consists of a city owned parking lot and four (4) permanent buildings. The Tybee Island Police Department (78 Van Horne Street) occupies a two-story building built in the early 1930’s along with a single story building adjacent to the main building. There is also a U-shaped, single story building (80 Van Horne Street) that is currently being used to store and repair parking meters, known as the Ceramic building. The site location is depicted on Figure 1 in Appendix A. A Site Plan showing the property configuration and location of soil and groundwater locations from the HGBD Environmental CAP Part A (1998) and the Terracon LSI (2012) field work is included as Figure 2 of Appendix A. No Further Action Confirmation Request Van Horn Property - Facility ID: 4250113*1 Tybee Island, Chatham County, Georgia July 26, 2012 Terracon Project No. ES127048 Responsive Resourceful Reliable 2 PREVIOUS ENVIRONMENTAL WORK 2.0 Two (2) abandoned underground storage tanks were identified at the site in October 1997 during utilities work at the site. After the tanks were closed, a UST Closure Report was submitted to EPD on November 13, 1997, prepared by HGBD Environmental, Inc. Groundwater sampling completed as part of the UST closure indicated an elevated Benzene concentration above the Maximum Contaminant Level. A Corrective Action Plan – Part A was prepared for the site and submitted to EPD in June 1998. Three (3) soil borings were installed in vicinity of the former tank pit area and converted to permanent monitoring wells. BTEX, PAHs, and TPH were not detected in any of the soil samples. The groundwater sample collected from CAP Part A well MW-2 showed detectable levels of Toluene, Ethylbenzene, and Xylenes. However, the levels were below both the USEPA MCL and the Georgia In-Stream water quality standards. A composite map showing the CAP-A sampling locations and the recent LSI sampling locations is included as Figure 2. RECENT ENVIRONMENTAL WORK 3.0 3.1 Limited Site Investigation A Limited Site Investigation (LSI) was conducted at the site for planned new Tybee Island Police Department building. Three (3) soil borings were advanced in the vicinity of existing USTs, existing dispensers, and CAP Part A monitoring well MW-2 (Figure 2) in order to determine the horizontal impact to the subsurface from the historical and existing USTs. The laboratory results indicate the presence of volatile organic compounds and semi-volatile organic compounds in the soils and groundwater at the subject site. The detected compounds are less than the Georgia EPD USTMP Table B Soil Threshold Levels (< 500 feet to surface water body). The groundwater analytical results indicate that all detected compounds were less than the Georgia In-Stream Water Quality standards in TW-2 and TW-3. Toluene, ethylbenzene, and Xylene (total) were detected at concentrations above the Georgia In-Stream Water Quality standards in TW-1, which was located in the general vicinity of CAP Part A well MW-2. Benzene was not detected in any of the soil or groundwater samples collected as part of the LSI, which is consistent with the CAP Part A analytical results. The soil and groundwater analytical data is summarized in Table 1 and Table 2 presented in Appendix B. Terracon’s LSI report, including the executed chain-of-custody form and laboratory data sheets, is included as Appendix C. No known leaks and/or loses from the existing UST system are recorded based conversations with the City of Tybee Island personnel familiar with the fueling operations at the site (i.e., Police Chief Robert Bryson). No Further Action Confirmation Request Van Horn Property - Facility ID: 4250113*1 Tybee Island, Chatham County, Georgia July 26, 2012 Terracon Project No. ES127048 Responsive Resourceful Reliable 3 3.2 Water Resources Survey Terracon completed a water resources survey to identify public and private wells within applicable radii of the site. Field reconnaissance did not indicate the presence of any private water supply wells within 0.5 mile of the site. The City of Tybee Island operates three (3) supply wells completed within the Floridan Aquifer within two (2) miles of the site. Hydrogeologic units in Chatham County, Georgia, include in descending order, the surficial aquifer system, consisting of the water-table zone, upper confined zone, and lower confined zone (Clarke, 2003); the Brunswick aquifer system, consisting of the upper Brunswick and lower Brunswick aquifers (Clarke and others, 1990); and the Upper Floridan aquifer (Miller, 1986; Clarke and others, 1990). In the vicinity of the subject site, the surficial aquifer system is generally present from land surface to 60 ft below land surface (bls). The surficial aquifer system is typically informally divided into a water-table zone, an upper confined zone, and a lower confined zone (Clarke, 2003). These water-bearing zones are separated by clay confining units. The confining unit underlying the surficial aquifer is represented by the A-marker horizon, which is present just above the Miocene upper confining unit (Clarke and others, 1990). The upper confining unit of Miocene age in the vicinity of the subject site extends from 60 to 140 ft bls. The Lower Brunswick aquifer is identified by Williams and Gill (2010) to be present in the vicinity of the subject site from 140 to 160 ft bls. The City of Tybee public supply wells are completed to produce water from the Upper Floridan aquifer. The top of the Upper Floridan aquifer at approximately 160 ft bls in the vicinity of the subject site. (Clarke and others, 1990; Williams and Gill, 2010). The City of Tybee wells range in depth from 402 ft to 602 ft bls. The location of the water supply wells and the subject site are presented in Figure 3. Mr. George Reese, City of Tybee Island Water and Sewer Department Director, was contacted concerning any impacts to any drinking water supplies from the subject site. Mr. Reese confirmed that there have been no known impacts to the water supply wells in the area and provided analytical data collected from Well No. 3 in 2011 indicating no detectable concentrations of volatile organic compounds. 3.3 Site Ranking The Site Sensitivity Score for the site using the soil and groundwater data collected in 2012 is 500. Terracon did not score any public wells as they are not hydraulically connected to the shallow surficial aquifer. All drinking water wells within a two mile radius of the subject property are cased at depths that exceed 150 feet below ground surface. APPENDIX A: FIGURES SI T E V I C I N I T Y M A P TY B E E I S L A N D V A N H O R N E S T R E E T S I T E Ge o r g i a E P D F a c i l i t y N o . 4 2 5 0 1 1 3 * 1 78 a n d 9 0 V A N H O R N E S T R E E T Ty b e e I s l a n d , C h a t h a m C o u n t y , G e o r g i a 1 ES 1 2 7 0 4 8 Ju l y 2 6 , 2 0 1 2 SA D SA D WS A WS A N. T . S . Pr o j e c t M a n a g e r : Dr a w n b y : Ch e c k e d b y : Ap p r o v e d b y : Pr o j e c t N o . Sc a l e : Fi l e N a m e : Da t e : Figure ES 1 2 7 0 4 8 - F i NO T E S : Im a g e f r o m G o o g l e E a r t h P r o 22 0 1 R o w l a n d A v e n u e S a v a n n a h , G e o r g i a 3 1 4 0 4 PH . ( 9 1 2 ) 6 2 9 4 0 0 0 F A X . ( 9 1 2 ) 6 2 9 4 0 0 1 SI T E - L o c a t i o n o f F o r m e r U S T s - T a n k 3 a n d T a n k 4 - L o c a t i o n o f C u r r e n t U S T s - T a n k 1 a n d T a n k 2 TW - 1 TW - 3 TW - 2 MW - 2 / B - 2 MW - 1 / B - 1 MW - 3 / B - 3 TAN K # 1 T A N K # 2 T A N K # 4 T A N K # 3 FO R M E R T A N K S P O L I C E D E P A R T M E N T VAN H O R N E S T R E E T F O R T A V E N U E TYB E E I S L A N D SUP P L Y W E L L N o . 2 TW - 3 MW - 1 / B - 1 Dr a w n B y : Ch e c k e d B y : Ap p r o v e d B y : Pr o j e c t M n g r : Fi l e N o . Da t e : Sc a l e : Pr o j e c t N o . Co n s u l t i n g E n g i n e e r s a n d S c i e n t i s t s Fi g u r e : 22 0 1 R o w l a n d A v e n u e S a v a n n a h , G e o r g i a 3 1 4 0 4 Fa x : 9 1 2 . 6 2 9 . 4 0 0 1 Ph o n e : 9 1 2 . 6 2 9 . 4 0 0 0 Ju l y 2 5 , 2 0 1 2 1 i n c h = 3 0 f e e t ES 1 2 7 0 4 8 WS A WS A SDSD TY B E E I S L A N D V A N H O R N E S T R E E T S I T E Ge o r g i a E P D F a c i l i t y I D N o . 4 2 5 0 1 1 3 78 A N D 8 0 V A N H O R N E S T R E E T Ty b e e I s l a n d , C h a t h a m C o u n t y , G e o r g i a SI T E P L A N 2 ES 1 2 7 0 4 8 - S I T E 0 3 0 ' 6 0 ' 1 I N C H = 3 0 F E E T 2- M i l e R a d i u s 3 1 1 SI T E 2 Dr a w n B y : Ch e c k e d B y : Ap p r o v e d B y : Pr o j e c t M n g r : Fi l e N o . Da t e : Sc a l e : Pr o j e c t N o . Co n s u l t i n g E n g i n e e r s a n d S c i e n t i s t s Fi g u r e : 22 0 1 R o w l a n d A v e n u e S a v a n n a h , G e o r g i a 3 1 4 0 4 Fa x : 9 1 2 . 6 2 9 . 4 0 0 1 Ph o n e : 9 1 2 . 6 2 9 . 4 0 0 0 Ju l y 2 5 , 2 0 1 2 ~1 i n c h = 1 , 5 0 0 f e e t ES 1 2 7 0 4 8 WS A WS A SDSD TY B E E I S L A N D V A N H O R N E S T R E E T S I T E Ge o r g i a E P D F a c i l i t y I D N o . 4 2 5 0 1 1 3 78 A N D 8 0 V A N H O R N E S T R E E T Ty b e e I s l a n d , C h a t h a m C o u n t y , G e o r g i a 20 1 1 T O P O G R A P H I C M A P 3 ES 1 2 7 0 4 8 - S I T E APPENDIX B: TABLES De t e c t e d A n a l y t e TW - 1 # 6 8' b g s (m g/ k g ) TW - 2 # 5 8' b g s (m g / k g ) TW - 3 # 5 8' b g s (m g / k g ) Re g u l a t o r y L i m i t ( m g / k g ) A Be n z e n e BR L B R L B R L 0 . 0 1 7 To l u e n e 32 . 5 B R L 4 . 8 9 1 1 5 . 0 0 Et h y l b e n z e n e 33 . 0 8 . 4 9 1 6 . 5 1 8 . 0 0 Xy l e n e ( T o t a l ) 28 7 4 4 . 8 2 1 1 7 0 0 . 0 0 Na p h t h a l e n e 6. 5 1 4 . 5 7 1 0 . 6 N / A 2- M e t h y l n a p t h a l e n e 14 1 0 . 6 2 2 . 1 N / A 1- M e t h y l n a p t h a l e n e 8. 5 7 6 . 4 4 1 6 . 1 N / A TO T A L P A H s 22 . 5 7 2 1 . 6 1 4 8 . 8 N / A BR L - B e l o w R e p o r t i n g L i m i t s A - Re g u l a t o r y L i m i t s - G e o r g i a E P D U S T M P T a b l e B S o i l T h r e s h o l d L e v e l s ( < 5 0 0 f e e t t o s u r f a c e w a t e r p o i n t ) BO L D - D e t e c t e d c o n c e n t r a t i o n e x c e e d s t h e a p p l i c a b l e r e g u l a t o r y l i m i t Te r r a c o n P r o j e c t N o . E S 1 2 7 0 4 8 TA B L E 1 : S O I L D A T A S U M M A R Y Ci t y o f T y b e e I s l a n d V a n H o r n e P r o p e r t y 78 a n d 8 0 V a n H o r n e S t r e e t Ty b e e I s l a n d , G e o r g i a De t e c t e d A n a l y t e TW - 1 (µ g / L ) TW - 2 (µ g / L ) TW - 3 (µ g / L ) In - S t r e a m W a t e r Q u a l i t y L i m i t (µg/L)A Be n z e n e BR L B R L B R L 5 1 To l u e n e 10 , 6 0 0 1, 1 3 0 3 7 8 5 , 9 8 0 Et h y l b e n z e n e 2, 5 3 0 1, 5 9 0 1 , 2 3 0 2 , 1 0 0 Xy l e n e ( T o t a l ) 15 , 6 0 0 7, 0 9 0 8 , 8 0 0 N / A Na p h t h a l e n e 84 9 5 8 5 8 6 2 N / A 2- M e t h y l n a p t h a l e n e 44 9 3 0 7 5 6 6 N / A 1- M e t h y l n a p t h a l e n e 24 8 1 7 6 3 4 4 N / A TO T A L P A H s 1, 5 4 6 1 , 0 6 8 1 , 7 7 2 N / A BR L - B e l o w R e p o r t i n g L i m i t s A - Re g u l a t o r y L i m i t s - G e o r g i a I n - s t r e a m W a t e r Q u a l i t y S t a n d a r d s Te r r a c o n P r o j e c t N o . E S 1 2 7 0 4 8 T A B L E 2 : G R O U N D W A T E R D A T A S U M M A R Y Ci t y o f T y b e e I s l a n d V a n H o r n e P r o p e r t y 78 a n d 8 0 V a n H o r n e S t r e e t Ty b e e I s l a n d , G e o r g i a Sa m p l e D a t e : M a r c h 2 3 , 2 0 1 2 1 3 9 Q 0 0 6 3 2 ° 0 . 0 ' 4 0 . 9 0 5 " N 8 0 ° 5 0 ' 3 1 . 8 5 5 " W P u b l i c S u p p l y 4 0 2 U n k n o w n 2 3 9 Q 0 0 1 3 2 ° 1 ' 2 4 . 5 2 6 " N 8 0 ° 5 0 ' 5 9 . 7 7 2 " W P u b l i c S u p p l y 6 0 6 U n k n o w n 3 3 9 Q 0 0 4 3 2 ° 1 ' 1 7 . 8 7 5 " N 8 0 ° 5 0 ' 4 3 . 4 1 2 " W P u b l i c S u p p l y 6 0 2 U n k n o w n To t a l D e p t h of W e l l (f e e t B G ) Casing Depth (feet BG) TA B L E 3 : W a t e r W e l l L o c a t i o n Ci t y o f T y b e e I s l a n d V a n H o r n e P r o p e r t y 78 a n d 8 0 V a n H o r n e S t r e e t Ty b e e I s l a n d , G e o r g i a Te r r a c o n P r o j e c t N o . E S 1 2 7 0 4 8 We l l N u m b e r o n Fi g u r e 3 US G S W e l l I D N o . La t i t u d e (d e g r e e s m i n u t e s se c o n d s ) Lo n g i t u d e (d e g r e e s m i n u t e s se c o n d s ) Us e o f W e l l