Newtown Creek Superfund Site CAG Meeting June 19, 2019 1 Region 2 - - PowerPoint PPT Presentation

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Newtown Creek Superfund Site CAG Meeting June 19, 2019 1 Region 2 - - PowerPoint PPT Presentation

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Region 2 serving the people of New Jersey, New York, Puerto Rico and the U.S. Virgin Islands Newtown Creek Superfund Site CAG Meeting June 19, 2019 1 Region 2 serving the people of New Jersey, New York, Puerto Rico and the U.S. Virgin Islands

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Newtown Creek Superfund Site CAG Meeting June 19, 2019

1 Region 2 serving the people of New Jersey, New York, Puerto Rico and the U.S. Virgin Islands

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SLIDE 2

2

  • Discuss CAG concerns related to operation of the

aeration systems in English Kills and East Branch

  • Concerns articulated in letters:
  • CAG Steering Committee – June 2015 letter to NYSDEC
  • NCA – March 2016 letter to US Army Corps – NY District
  • Goals of the presentation:
  • Discuss community concerns regarding aeration system as

they relate to the Superfund status of the site

  • Provide opportunity to ask questions

Region 2 serving the people of New Jersey, New York, Puerto Rico and the U.S. Virgin Islands

Introduction

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SLIDE 3

Summary of Key Community Concerns

  • Resuspension/disruption of contaminated

sediments by aeration

  • Aeration system effects on the transport of

contaminants by ebullition

  • Potential health impacts from aerosolization of

chemicals by aeration

  • Aerosolization of bacteria not addressed in this
  • presentation. (See evaluations provided by NYCDEP for more information:

https://www1.nyc.gov/site/dep/environment/east-branch-aeration.page.)

3 Region 2 serving the people of New Jersey, New York, Puerto Rico and the U.S. Virgin Islands

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Resuspension/disruption o

  • f

f contaminated sediments ts by y aera ration

4

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Aeration System

  • Aeration system was constructed by NYCDEP pursuant

to an administrative order on consent with NYSDEC

  • The aeration system was constructed and is operated

under regulatory oversight of NYSDEC.

  • Required to maintain dissolved oxygen levels >3 mg/L

during warm weather to support fish and biota survival

  • Aeration system constructed in upper and lower English

Kills and East Branch

  • Operates from May through September and is

periodically tested for short periods at other times

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English Kills Aeration System

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Aer Aeration S System em D Diffuse ser As Asse sembly Desi esign

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Height is about 14.5 inches

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SLIDE 8

Image of PVC header pipe/diffuser

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Sediment Resuspension

  • Total Suspended Solids (TSS) data provides insight into

potential resuspension of sediments by aeration

  • Surface water samples collected monthly in all sections
  • f Newtown Creek from Feb. 2012 to Jan. 2013
  • If aeration is causing sediment resuspension in English

Kills, expect to see increase in TSS during system

  • peration (May through September)

9 Region 2 serving the people of New Jersey, New York, Puerto Rico and the U.S. Virgin Islands

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Surface Water Sample Locations in English Kills

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Monthly Surface Water TSS Data Newtown Creek

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Harbor Survey TSS Data

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0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0

TSS Concentration (mg/L) Month

Harbor Survey Data 2008 to 2018 Total Suspended Solids Monthly Averages - English Kills Station (Dry Weather)

Top (May 2008 to 2018) Bottom (May 2008 to 2018)

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Surface Water TSS Data Summary

  • TSS data for English Kills do not show consistently elevated

TSS in summer months as would be expected if the aeration system was resuspending sediments.

  • The range of TSS concentrations is consistent with the range
  • f TSS concentrations in other creek reaches and tributaries

that don’t have aeration.

  • Air diffuser is elevated above the sediment (about 14

inches)

  • The TSS data does not suggest that the aeration system is

resuspending sediments.

Region 2 serving the people of New Jersey, New York, Puerto Rico and the U.S. Virgin Islands 13

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SLIDE 14

Aeration

  • n s

system em effec ects on t the transport rt o

  • f contaminants by

ebullition

10/20/2016 14

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Ebullition Process

  • Natural process occuring in sediment due to

decomposing organic matter

  • Naturally occuring bacteria in the subsurface create

gases (primarily methane) as a byproduct of their metabolism.

  • Gases build up in sediment until pressure exceeds the

confining forces of the sediment and water column above them

  • Gases fracture the sediment and rise in the water

column to the water surface.

  • Ebullition rates are generally higher in the summer due

in part to higher sediment temperatures.

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Ebullition-facilitated NAPL Transport Process

  • Gas bubbles create an air-water interface to which

hydrophobic chemicals and NAPL adhere to

  • NAPL-covered bubbles reach the water surface and

spread out forming sheens.

  • When sheens are no longer supported by the water’s

surface tension, the sheens descend through the water column and deposit on the sediment surface.

  • Ebullition-facilitated NAPL transport can transfer

contaminants from sediment to surface water and act to move contaminants from the sediments to other locations within the creek.

10/20/2016 16

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Ebullition Conceptual Model

17 Source: Modified from McLinn and Stolzenberg, 2009

Surface sheens decay and fall back to sediment

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Ebullition in Sediment

18 Region 2 serving the people of New Jersey, New York, Puerto Rico and the U.S. Virgin Islands Source: http://www.limno.com/pdfs/2013_Barabas_Lautenbach_Battelle_0213.pdf

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Aeration Effects on Ebullition

  • Ebullition rate is related to a number of factors including the organic matter in

the sediment, sediment temperature, the presence of gas forming bacteria, and the pressure of the sediment and water column.

  • Aeration does not impact the ebullition process or the rate of ebullition.

Aeration system bubbles originate in the water column while ebullition bubbles originate in and travel through the sediment bed before entering the water column.

  • The only potential effect of aeration on ebullition would be dispersal of

sheens on the water’s surface.

19 Region 2 serving the people of New Jersey, New York, Puerto Rico and the U.S. Virgin Islands

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Potential health th impacts from aerosolizati tion of ch chemicals by y aera ration

10/20/2016 20

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Aerosolization of Chemicals

  • Air sampling was conducted at Newtown Creek in June

2013 to assess potential impacts to air from site-related contaminants (VOCs and PCBs).

  • Air samples collected at shoreline and from in-creek

stations over a period of 24 hours

  • Used cannisters that collect continuous air samples at on-

creek and shoreline stations.

  • Sampling was conducted when the English Kills aeration

system was operating.

21 Region 2 serving the people of New Jersey, New York, Puerto Rico and the U.S. Virgin Islands

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Air Sampling Stations

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Air Sampling Results

  • Results of the air sampling did not show the presence
  • f VOCs and PCB Aroclors at concentrations above

background air concentrations (based on statistical tests at 95% confidence level)

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Potential Health Risks from Aerosolized Chemicals

  • Risk to shoreline recreations users from exposure to

chemicals in ambient air were well below EPA’s cancer risk range (1 E-4 to 1E-6)and non-cancer hazard index (1).

  • The BHHRA did not specifically quantify risks for exposure to

aerosolized droplets.

  • The HHRA did estimate risks to boaters and swimmers (and
  • thers) via ingestion and dermal contact with surface water.

Risks for these exposures were well below EPA thresholds.

  • Cancer risks for these exposures were 1 E-7 or lower, and

non-cancer hazards were 0.01 or lower.

24 Region 2 serving the people of New Jersey, New York, Puerto Rico and the U.S. Virgin Islands

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Potential Health Risks from Aerosolized Chemicals

  • For comparison:
  • Dermal Contact - Swimmers: HHRA assumed full body

contact with water for 1/2 hour per visit, 17 visits per year.

  • Dermal Contact - Boaters: HHRA assumed water

contact with head, hands, arms, legs, and feet for 2.5 hours per visit, 26 visits per year.

  • Dermal contact with aerosolized droplets is likely to be

less than these exposures.

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Summary

  • TSS data does not indicate resuspension or

disruption of sediment by the aeration system

  • No significant effect of aerations on ebullition-

facilitated NAPL transport process

  • Air data for VOCs and PCBs in English Kills were not

above background levels for samples collected when the aeration system was on.

  • Exposures from aerosolization of chemicals are

expected to be much lower than air, dermal, and ingestion risk to swimmers and boaters, which are well below EPA’s risk thresholds

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Discussion

  • Questions and comments?

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