Environmental Assessment of South Street

Transcription

1 Environmental Assessment of South Street 16 January 2018 Mark Martin, P.E. Barbara Butler, P.E. Chris Saranko, Ph.D., DABT

2 Agenda Review of Timeline Recent Events Site Assessment Overview Site Assessment Results Risk Analysis Options 2

3 Review of Timeline Mark Martin, P.E. Project Manager, Black & Veatch 3

4 Water System Operations (1930s & 1940s) : The original Water Treatment Plant (WTP) was located at the corner of Anderson Ave. (MLK Jr. Blvd.) & Cranford St. The WTP used lime softening to produce up to 2 million gallons per day (mgd) of potable water for City residents. 1947: A new wellfield was located south and west of the intersection of Martin Luther King Jr. Blvd. & Ortiz Ave. The wellfield served as water supply for the WTP. 1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s 2010s

5 Groundwater had a high concentration of calcium due to percolation through limestone deposits in the soil. A high concentration of calcium is defined as hard water. Hard water is treated through a softening process that removes calcium through the addition of lime. 5

6 Water System Operations (1950s & 1960s) : New facilities were built at the WTP to produce up to 10 mgd. Additional wells were also built at the wellfield. 1962: The City purchased undeveloped properties (now known as 3348 South St.) for the purpose of sludge disposal. Existing borrow pits on the site were used as a continuous fill sludge lagoon. 1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s 2010s

7 South Street Property Prior to Purchase 7

8 Lime sludge is a byproduct of the lime softening process and was traditionally treated as a waste product. The common nationwide practice was to dispose of lime sludge in the nearest watercourse. Beginning in 1962, lime sludge was continually placed in the sludge lagoons until they were full. Continuous fill sludge lagoons were a common practice in the 1960s & 70s. The deposition of lime sludge was prior to full residential development of the adjacent area. 8

9 What is Lime Sludge? When lime is added to hard water, a chemical reaction occurs that produces calcium carbonate. Calcium carbonate separates and settles out of the water. Lime sludge is about 95% calcium carbonate with some additional minerals that settle out of the water. Calcium carbonate is the predominant component in eggshells, sea shells and antacid tablets. 9

10 Aerial Timeline of South Street 1940s 1944 Aerial Photograph 10

11 Aerial Timeline of South Street 1950s 1953 Aerial Photograph 1958 Aerial Photograph 11

12 Aerial Timeline of South Street 1960s 1966 Aerial Photograph 1968 Aerial Photograph 12

13 Aerial Timeline of South Street 1970s 1972 Aerial Photograph 1975 Aerial Photograph 13

14 Aerial Timeline of South Street 1970s & 1980s 1979 Aerial Photograph 1986 Aerial Photograph 14

15 Aerial Timeline of South Street 1990s 1990 Aerial Photograph 1996 Aerial Photograph 15

16 Aerial Timeline of South Street 2000s 2002 Aerial Photograph 2007 Aerial Photograph 16

17 Aerial Timeline of South Street 2010s 2012 Aerial Photograph 2016 Aerial Photograph 17

18 Water System Operations (1960s 1970s) : A river pump station & pipeline were built to recharge the wellfield with water from the Caloosahatchee River : The sludge lagoon (borrow pits) on site were completely filled with sludge and operations ceased. 1977: Drinking water rule goes into effect which sets the standard for arsenic at 50 parts per billion (ppb). 1979: The State revises Chapter 17-7, F.A.C. This is the first environmental regulation governing the disposal of sludge. 1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s 2010s

19 Water System Operations (1970s 2000s) Late 1970s-Early 1980s: Lee County installs a potable water system in the area bounded by Edison Ave., Ford St., Canal St. & Highlands Ave : City builds a new WTP at the corner of Jacksonville St. & Canal St. The original WTP is decommissioned & lime sludge is no longer produced. 2006: Drinking water rule is updated which sets the standard for arsenic at 10 ppb. 1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s 2010s

20 Property History ( ) 1994: Habitat for Humanity was offered the property at 3348 South St. for purchase. Offer later withdrawn after determination that the soil stability was unsuitable for home construction. October 2002: City hired ERMI to conduct a visual inspection of the site. ERMI concluded that no evidence of dumping of lime sludge was observed with the exception of the possibility of vegetation covering the area of concern. They also concluded that no environmental concerns would exist if such dumping had occurred on site. 1990s

21 Property History ( ) October 2002: FDEP indicated that lime sludge is not considered to be a hazardous waste. The material can be used as fill, and if present, should not be a regulated source of soil or groundwater contamination. September 2003: Property is annexed into the City of Fort Myers as part of the Dunbar annexation. February 2007: City hired ASC Geosciences to conduct testing at the property and lime sludge is discovered. The sludge is sampled, tested and found to contain arsenic concentrations higher than the residential cleanup standard. 1990s

22 Property History ( ) April 2007: City Council established funding for a Home-a- Rama project on the property. City indicated they would work with FDEP to implement a cost-effective solution to mitigate the lime sludge. April 2008: City hired ACT to perform a groundwater assessment. ACT installed 6 monitor wells & sampled groundwater. Arsenic was detected in 2 of the 6 wells at concentrations slightly higher than the drinking water standards. 1990s

23 Property History ( ) July 2008: FDEP reviewed the groundwater assessment and requested the City to submit a remedial action plan (RAP) for the property. July 2010: After discussions with FDEP, City submitted a RAP which included semi-annual monitoring of the groundwater for 5 years. FDEP accepted the RAP. August 2010: City began groundwater sampling & testing on a semi-annual basis. Sampling occurred every February and August. 1990s

24 Property History ( ) April 2012: FDEP reduced the groundwater sampling frequency from semi-annual to annual, beginning in August January 2017: FDEP reduced the groundwater sampling frequency from annual to biennial (every other year). The next groundwater sampling is scheduled for September s

25 Recent Events Mark Martin, P.E. Project Manager, Black & Veatch 25

26 Recent Events (June July 2017) June 2017: FDEP made a presentation regarding lime sludge at a regular City Council meeting. FDEP stated there was no evidence that the contaminant was moving from the site and the lime sludge could remain in place as long as the groundwater was not contaminated and causing harm to others. FDEP recommended additional sampling be completed. July 2017: City hired GFA to perform an environmental site assessment of the property. GFA submitted a work plan which was subsequently approved by FDEP. City hired B&V to evaluate & oversee the site investigations. 26

27 Recent Events (August December 2017) August 2017: City conducted a public information meeting to provide information on the environmental assessment work plan and receive public comments. August - September 2017: Extensive rainfall from tropical storms & Hurricane Irma flooded the site and made the property inaccessible for sample collection. October 2017: Groundwater sample collection at onsite monitor wells. Standing water collection at the site. November December 2017: Sludge/soil sample collection at site. Installation of offsite monitor wells. Groundwater sample collection at onsite & offsite monitor wells. 27

28 Site Assessment Overview Barbara Butler, P.E. Project Manager, Black & Veatch 28

29 Scope of Site Assessment Perform sampling and analytical testing to: Characterize lime sludge (what chemicals does it contain?) Define vertical extent of sludge (how deep is it?) Characterize groundwater conditions Estimate groundwater flow direction Evaluate potential exposure risks (are there any community or environment impacts?) Present sampling & testing results in a report and make presentations to the public 29

30 Site Assessment Goals Evaluate potential risks to human health Evaluate potential risks to groundwater resources Collect data to make redevelopment decisions 30

31 Data Collection Achieve goals by collecting field data: Installation of offsite monitor wells Water levels at onsite & offsite monitor wells Groundwater samples from onsite & offsite monitor wells Water samples from standing water onsite Sludge/soil samples onsite Achieve goals by evaluating field data: Evaluate human health risk Determine groundwater resource risk by evaluating leachability data Determine sludge thickness 31

32 Site Assessment Results Barbara Butler, P.E. Project Manager, Black & Veatch Site Assessment data provided by GFA International, Inc. 32

33 Groundwater Sampling/Water Level Measurements 6 onsite monitor wells in October onsite & 5 offsite monitor wells in December 2017 October 2017 samples analyzed for > 200 constituents Priority pollutants Drinking water quality parameters Including: Metals Organic chemicals Inorganic chemicals Radionuclides 33

34 Groundwater Sampling/Water Level Measurements December 2017 onsite samples analyzed for 5 metals & total dissolved solids, based on October 2017 sampling results December 2017 offsite samples analyzed for 13 metals & total dissolved solids Samples analyzed by FDEP-certified laboratory (TestAmerica) 34

35 Monitor Well Locations 35

36 Groundwater Flow Direction Is North/Northwest 36

37 Groundwater Sampling Results - October 2017 No organic chemicals. Common naturally occurring groundwater metals: arsenic, aluminum, barium, chromium, copper, lead, iron, manganese, molybdenum, nickel, selenium, sodium. Arsenic exceeds primary drinking water standard (PDWS) in 3 of 6 monitor wells. Radionuclides exceed PDWS in one sample. All 6 monitor wells contain at least one metal or quality exceeding secondary drinking water standard (SDWS). Metals such as iron and manganese. Total dissolved solids and color. 37

38 Onsite Monitor Wells with Arsenic > PDWS 38

39 Groundwater Sampling Results - December 2017 Only 5 metals detected: arsenic, aluminum, iron, manganese & molybdenum. Only arsenic > PDWS. 3 of 6 onsite monitor wells. 3 of 5 offsite monitor wells. Aluminum, iron, manganese & total dissolved solids > SDWS in multiple onsite and offsite monitor wells. Molybdenum above FDEP criterion in one offsite monitor well 39

40 Onsite/Offsite Monitor Wells with Arsenic > PDWS 40

41 Area Public & Private Wells City public wells are upgradient > 1 mile to east. Lee County public wells are upgradient > 12 miles to southeast. Nearest irrigation well is one block to northeast. Groundwater from City public wells is > 600 feet. Groundwater from irrigation wells is about 200 feet. Onsite & offsite monitor wells are < 12 feet below ground surface. 41

42 Irrigation Well Locations Groundwater flow is in opposite direction from water supply & nearby irrigation wells. Water in irrigation wells is separated from water in onsite/offsite monitor wells by a confining layer at about 20 depth 42

43 Standing Water Sampling 3 locations of standing water in October 2017 Samples analyzed by FDEP-certified laboratory (TestAmerica) Samples analyzed for 19 metals 12 metals detected including arsenic All metals concentrations < PDWS METALS CONCENTRATIONS IN STANDING WATER POSE NO RISK 43

44 Standing Water Sample Locations 44

45 Sludge Sampling Sludge samples collected in November Collected continuous samples from ground surface to below maximum depth of sludge at 25 locations. Samples for chemical analysis collected between 0.5 & 9 feet Samples analyzed by FDEP-certified laboratory (TestAmerica) Sludge samples collected from 22 locations where sludge was present 5 of 22 samples analyzed for full list of priority pollutants 17 of 22 samples analyzed for priority pollutant metals 10 samples analyzed for leachable arsenic 45

46 Sludge Sample Locations 46

47 Sludge Sampling Results Sludge observed at 22 of 25 locations Sludge moist, light brown in color Sludge present at ground surface at 22 locations Minimum sludge depth = 3 feet Maximum sludge depth = 14 feet 47

48 Sludge Sampling Results Sludge No organic chemicals in 5 of 5 samples As expected, range of metals in 22 0f 22 samples Arsenic in 22 of 22 samples Concentration by sample depth 0.5 to 2 feet: mg/kg 3 to 5 feet: mg/kg 6 to 9.5 feet: mg/kg Leachate Arsenic in 1 of 10 samples (DP-1) Concentration = mg/l Concentration significantly lower than FDEP criteria Corresponding sludge concentration is 10.8 mg/kg ARSENIC IN LIME SLUDGE NOT LEACHING TO GROUNDWATER 48

49 Sludge Sample & Well Locations 49

50 Site Assessment Conclusions Source of arsenic in groundwater is not lime sludge City public water supply wells are > 1 miles from site County public water supply wells are > 12 miles from site Groundwater flow at site is away from City/County/nearby irrigation wells Depth of public & private wells are significantly below the confining layer 50

51 Risk Analysis Chris Saranko, Ph.D., DABT Principal Toxicologist, Geosyntec Consultants 51

52 Arsenic Levels in U.S. Surface Soils Arsenic is a naturally occurring element (20 th most abundant in the earth s crust) Map shows natural background concentrations of arsenic in surface soils throughout the U.S. Soil arsenic levels are above 10 mg/kg in large areas of the country. There is no evidence of a link between soil arsenic and adverse health effects in these areas. 52

53 Risk Assessment Overview Risk assessment is a regulatory tool used to establish safe levels of exposure to chemicals in soil, groundwater, etc.

54 FDEP s Risk-Based Corrective Action Framework FDEP has established rules (Chapter and , F.A.C.) that provide a framework for the investigation and cleanup of properties impacted by chemical contaminants. The residential and commercial/industrial cleanup target levels (CTLs) incorporate exposure assumptions that intentionally overestimate potential exposures for the majority of the population. 54

55 Soil Cleanup Target Levels (SCTLs) FDEP residential arsenic SCTL = 2.1 mg/kg. FDEP commercial/industrial arsenic SCTL = 12.0 mg/kg. These default CTLs for soil are walkaway numbers that are defined as safe. FDEP recently approved an arsenic SCTL of > 10 mg/kg for recreational exposures. USEPA Region 4 residential arsenic cleanup levels typically range from 20 to 50 mg/kg.

56 Simplified Risk Calculation Risk = Dose x Toxicity Dose [Soil Conc] x [Soil Ingestion] x [Exposure Freq] x [Exposure Duration] [Body Weight] x [Constants] Soil Cleanup Targets solve the equation for soil concentration given a desired risk level Dose = Target Risk / Toxicity

57 Protective Assumptions The default residential SCTLs assume: People live on the contaminated property for 30 years starting at birth. All the soil/dust that people come into contact with comes directly from the contaminated property they live on. Exposure to soil occurs by ingestion, breathing, and skin contact. These exposures occur on a daily basis, year in, year out.

58 Typical Daily Arsenic Intakes Daily arsenic intakes associated with soil at FDEP s default residential and industrial SCTLs and detected site concentrations are well below typical daily intakes from water, dietary, and other sources.

59 Conclusion The detected soil arsenic concentrations do not pose a shortor long-term health concern to people in the surrounding neighborhood.

60 Options Mark Martin, P.E. Project Manager, Black & Veatch 60

61 Conclusions Source of arsenic in groundwater is not lime sludge Arsenic concentrations in standing water pose no risk Arsenic concentrations in sludge do not pose a short- or long-term health concern to people in the surrounding neighborhood. In accordance with , F.A.C., the lime sludge is not required to be removed from the site. 61

62 Options The City has the following options in handling the lime sludge, with continued FDEP coordination: No further action Property remains in its current condition Provide a cap (concrete, asphalt, soil) over the lime sludge Passive park with walking or exercise trails Remove & replace the top 2 of lime sludge and stabilize Active park with sports areas or picnic area Completely remove & replace the lime sludge Residential development 62

63 Mark Martin January 2018