gowanus canal fs tests are started more than 2 weeks after collection, it is desirable to conduct...

Gowanus Canal FS

EPA Meeting

April 26, 2012

2

Agenda Meeting Topic 1 : Ecological PRG – Concerns with Amphipod Data Concerns with Dose- Response Relationship City’s PRG for Total PAH

Meeting Topic 2 - Concerns with CSO data – Collection Methods Quality of the Data Estimates and Interpretation

Meeting Topic 3 – Lack of Conceptual Site Model for the Canal All Sources not Characterized Impact of Groundwater Solids balance

3

Topic 1: Concerns with EPA Ecological PRG

4

Open Uncertainties Regarding Amphipod Testing

Exceeding Recommended Holding Times?

EPA’s Leptocheirus Guidance (2001) recommends two weeks holding times and always less than 8 weeks to minimize test variability and effects on toxicity (in ether direction)

EPA ARCs states “Recommended sediment holding time ranges from less than two (ASTM 1993) to less than 8 weeks (USEPA-USACOE 1993). If whole-sediment toxicity tests are started more than 2 weeks after collection, it is desirable to conduct additional characterizations of sediment to evaluate possible effects of storage on sediment.”

Were final tests re-run on the same test sediments as used in the first two failed tests, on new samples, or on an archived subsample?

EPA Leptocheirus Guidance recommends minimal disturbance of test sediments

‒ Unclear how samples were sub-sampled three times without significant disturbance of samples

Assessment and Remediation of Contaminated Sediments (ARCS) Program, Assessment Guidance Document Chapter 6, US Environmental Protection Agency. 1994. ARCS Assessment Guidance Document. EPA 905-B94-002. Chicago, Ill.: Great Lakes National Program Office. EPA 600/R-01/020, March 2001, Method for Assessing the Chronic Toxicity of Marine and Estuarine Sediment-associated Contaminants with the Amphipod Leptocheirus plumulosus, Office of Research and Development, Western Ecology Division, U.S. Environmental Protection Agency

5

Open Uncertainties Regarding Amphipod Testing

Was sample exhausted?

If sample was exhausted, how were experimental samples held between restarts of the Lepthcherius test?

How were sediments held between attempts?

EPA does not address the potential changes in the sediment during the unspecified periods between trials;

The EPA laboratory report does not address or explain the revised testing – the reference to these re-trials occurs only in a footnote to the text.

6

Station 326

Reason for Exclusion Comment Closest to canal with highest likelihood of canal influences

(1) Station 326 had the lowest concentration of total PAHs (1.8 ppm) of all the references stations indicating little influence from canal.

Highest frequency of metal criteria exceedances and only reference area station to exceed SELs for chromium, lead, and silver

(1) Station 326 did not exceed the SEL for Chromium (2) Station 326 slightly exceeded the SEL for Lead

based on an estimated value (3) Frequencies of exceeding LELs are (10/11 at 326;

6/11 at 328; 9/11 at 329; 7/11 at 330 and 333)

NYC recommends retaining station 326 as a reference station because it does not appear to be under the influence of the canal (very lowest measured PAH concentrations) and contributes to the range of reference conditions inherent in a reference envelope approach.

7

Range of PRGs Based on Leptocheirus Tests

Value (ppm)

Source Endpoint Basis

39 EPA Survival NOAEC from Graphical Method

39 NYC Survival Maximum Concentration at Site Station(s) Within Reference Envelope Survival

24.5 NYC Survival Average Concentration of Non-Toxic Site Stations (if station 326 is retained as a reference station)

7.8 EPA Growth NOEAC from Graphical Method

39 NYC Growth Statistical Comparison of Site Sample Toxicity (station 303) to Toxicity at EPA NOAEC Sample (station 328)

39 NYC Growth Maximum Concentration at Site Station(s) Within Reference Envelope Survival

26.7 NYC Growth Average Concentration of Non-Toxic Site Stations (if station 326 is retained as a reference station)

7.8 EPA Repro. NOAEC from Graphical Method 33.9 NYC Repro. Statistical Comparison of Site Sample Toxicity (station

321) to Toxicity at EPA NOAEC Sample (station 328)

25.4 NYC Repro. Average Concentration of Non-Toxic Site Stations (if station 326 is retained as a reference station)

8

EPA Comment Regarding PRG at Reynolds Metal

Reynolds Metal PRG of 10 ppm total PAH was “based on ingestion of fish by local residents and represent sediment contaminant concentrations which would be associated with carcinogenic risks on the order of 10[-4]”

EPA/ROD/R02-93/201, 1993, EPA Superfund Record of Decision: REYNOLDS METALS CO EPA ID: NYD002245967 OU 01, MASSENA, NY, 09/27/1993

9

PRG of 7.8 is Outside Range at Other Sites The Gowanus Canal PRG (EPA Estimate) for Total PAHs is 2 to 18 Times Lower Than Those Developed at Other Sites Nation-Wide:

PRGs From Various Sites Nation-Wide Applied to Gowanus Canal (assuming 6.4% TOC in Gowanus Canal based on Table 1.1 Summary of Sediment Physical Characteristics Gowanus Canal Feasibility Study) Site Site-Specific

PRG Total PAH ppm

Basis of PRG Development PRG Applied to Gowanus Canal Conditions (ppm)

Basis of Application

Gowanus Canal – NYC Estimate

85 25 to 39

(1) Based on Nereis Toxicity (2) Based on Leptocheirus Toxicity

85 25 to 39

Mean concentration among non-toxic samples

Gowanus Canal EPA Estimate

7.8 (1) Leptocheirus Toxicity 7.8 See critique of method in prior slides

Buffalo River 16 (1) Ten Day Benthic Toxicity Tests (2) Benthic Invertebrate Equilibrium Partitioning Model (3) Target Lipid Model for Invertebrates (3) Chronic Invertebrate Toxicity Testing

16 Provided as Bulk Sediment Concentration

Steven’s Point, WI 22.8 (1) Adopted Probable Effects Levels for Invertebrates from MacDonald et al. 2000.

22.8 Provided as Bulk Sediment Concentration

Grand Calumet River, Lake Michigan

30.8 (1) 28 Day Benthic Toxicity Tests (2) Regression Analysis (3) Comparison to Threshold Values for protection of benthic organisms and Effect Levels From Literature (to demonstrate validity of site specific calculations)

24.3 Extrapolated from Calumet Site PRG of 3.8 ppm @ 1% TOC and adjusted for Gowanus Canal TOC

Indiana Harbor, Lake Michigan

45.8 (1) 28 Day Benthic Toxicity Tests (2) Regression Analysis (3) Comparison to Threshold Values for protection of benthic organisms and Effect Levels From Literature (to demonstrate validity of site specific calculations)

36.5

Extrapolated from Indiana Harbor Site PRG of 5.7 ppm @ 1% TOC and adjusted for Gowanus Canal TOC

Elizabeth River, VA 45 (1) Regional Benthic Toxicity Studies (2) Application Of An Exposure Model To Site Specific Sediment Data, (3)Comparison Between Onsite And Background Sediment [PAH]

45 Provided as Bulk Sediment Concentration

Duwamish 79 Human Health Effects 79 Provided as Bulk Sediment Concentration

Ashland Northern States Power

9.5 (1) Benthic Toxicity Testing (2) Comparison to Benthic effects benchmarks

146

Extrapolated from Ashland PRG of 9.5 ppm @ 0.415% TOC and adjusted for Gowanus Canal TOC

11

Topic 2: Concerns with CSO Data

12

CSO Data Collection EPA’s Sampling Program for CSOs consisted of the following:

COPC measurements on CSO solids from pipes. (These data were not used by EPA although the samples are a direct measure of CSO solids)

COPC measurements on CSO effluent during wet weather event

Includes limited composite measurements.

For PAHs, only whole water analysis was conducted. Separate phases were not analyzed yet EPA’s estimate of the solids phase concentration is the basis for its remedy selection for CSOs.

Highly variable nature of CSO TSS concentrations lead to very uncertain estimates of contaminant concentrations on CSO solids.

13

Duplicate results collected by EPA for CSOs show inconsistent agreement.

There are differences in the absolute values as well as the PAH signature among duplicates

CSO Datasets have a High Degree of Uncertainty – Poor Agreement with Duplicates

Analyte

Actual Concethe ntration (ug/L) Percentage of Total PAH Concentration

RH-033 Duplicate

RH-033 OH-007

Duplicate OH-007

RH-033 Duplicate

RH-033 OH-007

Duplicate OH-007

2-Methylnaphthalene 2.1 0.2 0.26 12% 10% 10%

Acenaphthene 1.1 1.7 0.21 0.19 100% 10% 10% 7%

Acenaphthylene

Anthracene 0.16 0.15 1% 6%

Benzo(a)Anthracene 0.19 0.096 0.15 1% 5% 6%

Benzo(a)Pyrene

Benzo(b)Fluoranthene 0.39 0.21 0.29 2% 10% 11%

Benzo(g,h,i)Perylene 0.42 2%

Benzo(k)Fluoranthene 0.066 0.15 0.25 7% 10%

Chrysene 0.13 0.12 0.19 1% 6% 7%

Dibenz(a,h)Anthracene 0.11 0.16 0% 5% 6%

Fluoranthene 0.44 2%

Fluorene 0.33 0.14 0.21 2% 7% 8%

Indeno(1,2,3-c,d)Pyrene 0.39 2%

Naphthalene 10 0.23 0.35 57% 11% 14%

Phenanthrene 0.89 0.27 0.35 5% 13% 14%

Pyrene 0.41 0.3 2% 15%

Total PAH 1.1 17.616 2.036 2.55 176% RPD 22% RPD

14

CSO Datasets have a High Degree of Uncertainty – Poor Agreement among Duplicates

CSO Weather

Event Sample

Type Aluminum (ug/L) Iron (ug/L) Lead (ug/L)

Magnesium (ug/L)

RH-033 WWE 1 N 331 2220 21.6 5790

RH-033_Dup WWE 1 FD 1620 J 8800 103 75000 U

OH-007 WWE 3 N 200 U 1180 J 56.4 2910 J

OH-007_Dup WWE 3 FD 137 J 858 J 50.6 2680 J

15

Composite samples were not collected by EPA to characterize the CSOs.

Sampling for CSOs needs to account for first flush and a composite sample for the “rest of the storm”. From some results, it appears that the captured sample is “first flush”.

TSS results show high variability for different wet weather events. Average Relative Percent Difference of 100 %.

For some CSOs (RH-035, RH-037) the dry weather TSS is significantly less than the Wet Weather TSS result.

Anticipated Dry weather TSS results are ~ 120 mg/L. RH-038 has TSS of 467 mg/L ( 4 times the anticipated value).

For duplicate analytical results, duplicate TSS values were not reported (measured?)

Duplicates do not appear to be collected for TSS data.

TSS result was not reported by EPA for RH-034 Wet Weather Event 3.

10

100

1000

TSS

(mg/

L)

TSS for Wet and Dry Weather Events

WW1

WW2

WW3

Dry

0%

20%

40%

60%

80%

100%

120%

140%

160%

180%

Rel

ativ

e Pe

rcen

t Diff

eren

ce fo

r TSS

TSS Variability among Wet Weather Events

CSO Datasets have a High Degree of Uncertainty – Wide variability in the TSS Results

16

EPA’s Evaluation of the available CSO Data is questionable

PAH data collected for solids in CSO Pipes (the only measurement available for CSO solids) was not used by EPA

EPA ‘s methodology to estimate PAH concentration on CSO solids is overly conservative and results in overestimation of Total PAH concentration on CSO solids.

EPA assumes that all the PAH mass is on the CSO solids – does not account for soluble PAHs

No correlation between TSS and Total PAH is observed to support this methodology

EPA’s Interpretation of the CSO Data is Questionable

17

EPA has discounted the data collected from CSO pipes under the premise that solids in the pipes are coarse.

PAH in solids from CSOs do not correlate with grain size distribution.

Flow weighted Total PAH concentration of solids from CSO pipes is 9.5 ppm which essentially meets the EPA PRG of 7.8 ppm

CSO Solids Data from Pipes

0

5

10

15

20

0 10 20 30 40 50 60

CSO Pipe SolidsPercent Fines vs. Total PAH

RH-033

RH-031

RH-036

OH-007

RH-037

RH-035OH-005Tota

l PA

H (m

g/kg

)

Percent Fines

Major CSOs shown in bold

18

LMW PAHs, which are soluble in water, account for more 60% of the TPAH Concentration in CSO Effluent.

2-methyl Naphthalene and Naphthalene on an average account for 49% of the LMW PAH concentration and 35 % of the TPAH concentration.

CSO Wet Weather Data – LMW / Total PAH Ratio

On average, more than half of the Total PAH concentration is dissolved making EPA’s estimates of the solid phase biased high.

19

There is no correlation between TSS and Total PAH.

CSO Wet Weather Data – TSS vs. TPAH

This further discounts EPA’s theory that all PAH mass is on the solids.

TSS (mg/L)

Expanded Scale

20 20

From Gasperi et al., 2011Total Concentration (ug/L)

Rings Parameters Min Max Mean N Min Max Mean2 Naphthalene* 0.09 0.22 0.13 4 0% 80% 52% 69%3 Acenaphthalene 0.01 0.03 0.02 4 69% 70% 70% 70%3 Acenaphthene 0.00 0.01 0.00 4 0% 0% 0%3 Anthracene* 0.01 0.04 0.02 4 0% 23% 11% 22%3 Fluorene 0.01 0.04 0.03 4 0% 100% 52% 69%3 Phenanthrene 0.07 0.24 0.16 4 15% 41% 30% 30%4 Benzo(a)anthracene 0.05 0.17 0.13 4 0% 0% 0%4 Chrysene 0.08 0.27 0.19 4 0% 0% 0%4 Fluoranthene 0.13 0.37 0.28 4 2% 15% 7.5% 7.5%4 Pyrene 0.14 0.41 0.29 4 2% 12% 6.5% 6.5%5 Benzo(a)pyrene* 0.06 0.20 0.13 4 0% 8% 2.9% 5.5%5 Benzo(b)fluoranthene* 0.10 0.37 0.23 4 0% 0% 0%5 Benzo(b)fluoranthene* 0.04 0.13 0.08 4 0% 0% 0%6 Benzo(ghi)perylene* 0.07 0.26 0.14 4 0% 9% 2.3% 9.1%6 Indeno(cd)pyrene* 0.07 0.25 0.14 4 0% 12% 3% 12%

Total PAHs 0.96 2.67 1.97 4 2% 19% 11.8% 11.8%Fraction Naphthalene 3% 12% 8% 4

From Huang and Foster, 2006Total PAHs 1.50 12.50 ? 3% 32%

Fraction Naphthalene+C1 3.8% 4.6%

EPA DataCSOs Excluding Impacted CSOs

Total PAHs 1.7 3.7 2.6Fraction Naphthalene+C1 10% 60% 26%

Impacted CSOsTotal PAHs 1.0 34.0 10.7

Fraction Naphthalene+C1 36% 93% 64%

PAHs in CSOs, Paris, France

PAHs in Stream Flow receiving SWOs, Washington, DC

Gowanus Canal CSOs

Fraction Dissolved Mean(meas'd

PAH Partitioning Behavior is Unresolved

21

City estimated the TPAH concentration on solids from CSOs as follows:

Assumed Equilibrium Partitioning.

Partitioning coefficients from Agency for Toxic Substances and Disease Registry (ATSDR) were used.

Non-detected results with an RL of 1 ug/L were excluded.

On average, EPA estimate is 4.5 times that of City’s Estimate

Median is 2 times greater

City’s Estimates of TPAH Concentration on Solids from CSOs

1

10

100

1000

1 10 100 1000

USE

PA E

stim

ate

- mg/

kg

Partitioning-based Estimate - mg/kg (NYC DEP)

22

Comparison of City and EPA Estimates from CSO Wet Weather Data

0.1

1

10

100

0.1 1 10 100

USE

PA E

stim

ate

- mg/

kg


2-Methylnaphthalene

0.1

1

10

100

0.1 1 10 100

USE

PA E

stim

ate

- mg/

kg

Equilibrium-based Estimate - mg/kg (NYC DEP)

Benzo(a)Pyrene

0.0001

0.001

0.01

0.1

1

10

0.0001 0.001 0.01 0.1 1 10

USE

PA E

stim

ate

- mg/

kg


Acenaphthylene

0.1

1

10

100

0.1 1 10 100

USE

PA E

stim

ate

- mg/

kg

Equilibrium-based Estimate - mg/kg (NYC DEP)

Benzo(b)Fluoranthene

23

Summary – Total PAH

Approach Ecological PRG TPAH (mg/kg)

Assumptions Sample Type

TPAH Concentration on CSO Solids (mg/kg)

Min Max Flow weighted

Average

EPA 7.8

1) All PAHs on Solids Wet Weather

Samples 4 330 50

NYC-DEP 85 1) Does not include non-detects with RL of 1 ug/L

2) Equilibrium partitioning

Sediment in CSO Pipes

1.1 18.3 9.5

Wet Weather Samples

2 88 28

24

Summary – Four Largest CSOs

TPAH Concentration (mg/kg)

CSO % of Total Discharge

Sediment in CSO Pipes

City Estimate EPA Estimate Comparison with City’s Ecological PRG (85ppm)

RH-034 32% NA 37 65 Less than City's PRG

RH-035 29% 3 8 13 Less than City's PRG

OH-007 18% 17 35 57 Less than City's PRG

RH-031 9% 18 46 103 EPA Estimate Exceeds City's

PRG

25

Topic 3: CSM Issues for the Site

26

Lack of CSM for the Site EPA has not developed a conceptual site model (CSM) for the site. All the Sources in the site have not been characterized:

Extent of the NAPL and its impact on CSOs and Canal is not well understood

CSOs have not been sufficiently characterized. Current datasets do not provide a thorough characterization

~200 unpermitted outfalls have not been evaluated

Impact of groundwater on the Canal is not accounted

Harbor Exchange is unaccounted for

27

CSM Issues

Direct evidence for NAPL impacts on CSO discharges

Evidence for Solids Contributions

Bathymetry

Metals Balance

PAH sources not fully identified

PAH balances

CSO vs Surface Sediments

Individual compound basis

Groundwater Transport

28

Possible Impact of NAPL on the Canal and CSOs

TPAH (ug/L) - NY City CSOs from CARP

CSOs near Fulton Site

Impact of NAPL on the Canal has not been evaluated completely. Of the three MGP sites only one site has been characterized by DEC Effluent data from CSOs indicates that there is a potential impact of MGP sites on CSOs.

29 For the potentially impacted CSOs, the sum of 2-Methylnaphthalene and Naphthalene,

concentration is more that 10 ug/L and accounts for 69% or more of the Total PAH Concentration

CSOs – Owls Head CSOs – Red Hook Mean Concentration Percentage of Total PAH Concentration

Fulton Site

Possible Impact of MGP Sites on CSOs

30

CSO Pipes at Fulton Site

Boundaries of MGP Site Potentially Impacted CSO

31

Solids Balance in the Canal EPA does not account for solids mixing in the Canal.

EPA has used the bathymetry data to characterize the deposition patterns in the Canal.

Based on the observed patterns EPA asserts that CSOs are responsible for all the solids that settle in the Canal especially at the head end.

EPA does not account for solids entering the Canal from the harbor.

CSO discharges occur roughly 75 times per year

Remainder of the year, water column solids originate from resuspension or the harbor

The gross amount of solids entering the Canal from the Harbor is an order of magnitude higher than the amount of solids from CSOs.

Entity Flow (MG/Yr) TSS (mg/L) Mass (kg/yr)

CSO 377 70 100,000

Tidal 40,795 10 1,500,000

32

Results of Bathymetric Comparison

CSO Solids cannot account for more than approximately 20% of solids that settle in the Canal!!!

Change in Elevation from June 2003 to January 2010 (6.6 years)

Acres Deposition Erosion Net

(Deposition - Erosion)

CSO Discharge

(MGY) TSS (mg/L)

%Solids from CSOs vs. Net Deposition

Whole Study Area

Volume (cy)

28

31,000 20,000 11,000 377 136

20% Rate (cy/yr) 5,000 3,000 2,000

Mass (kg/yr)* 2,900,000 1,900,000 1,000,000 195,000

Head End to Carrol Street Volume (cy)

3 6,000 500 5,500

125 136 13% Rate (cy/yr) 900 100 800

Mass (kg/yr)* 550,000 60,000 490,000 65,000 Head End to 4th Street Turning Basin

Volume (cy) 5

9,500 1,000 8,500 194 136

14% Rate (cy/yr) 1,400 200 1,200 Mass (kg/yr)* 855,000 120,000 735,000 100,000

33

Iron and Total Fines Content Along the Gowanus Canal

0

10000

20000

30000

40000

50000

60000

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Iron

(mg/

kg)

Distance from the Gowanus Bay (miles)

Iron Concentration along the Gowanus Canal

Canal Sediments Reference

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

100.00

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

% F

ines


Total % Fines along the Gowanus Canal

Canal Sediments

34

Iron and Total Fines Content Along the Gowanus Canal

0

10,000

20,000

30,000

40,000

50,000

60,000

30 40 50 60 70 80 90 100

Iron

(mg/

kg)

Percent Fines

Iron vs Fines Surface Sediments

Surface Sediments Reference

35

Iron Concentration in Surface Sediments and CSOs

1,000

10,000

100,000

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Fe (m

g/kg

)

Distance from Gowanus Bay (miles)

Fe Surface Sediments and CSO Solids

Surface Sediments CSO-Pipes CSO - Wet Weather Ref

36

Aluminum in Surface Sediments vs. CSO Wet Weather Solids

100

1,000

10,000

100,000

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Al (

mg/

kg)


Al Surface Sediments and CSO Solids

Surface Sediments CSO-Pipes CSO - Wet Weather Ref

37

Pb/Fe Ratio in Surface Sediments vs. CSO Wet Weather Solids

0.001

0.01

0.1

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Pb/F

e


Pb/Fe Surface Sediments and CSO Solids

Surface Sediments

CSO-Pipes

CSO - Wet Weather

Ref

38

Cu/Fe Ratio in Surface Sediments vs. CSO Wet Weather Solids

0.001

0.01

0.1

1

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Cu/

Fe


Cu/Fe Surface Sediments and CSO Solids

Surface Sediments

CSO-Pipes

CSO - Wet Weather

Ref

39

TOC Along the Gowanus Canal

0%

2%

4%

6%

8%

10%

12%

14%

16%

18%

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

%TO

C


TOC Concentration along the Gowanus Canal

Canal Sediments Reference

40

Solids Contribution: Chemical Mass balance for Pb & Al Preliminary Analysis for Solids Contribution:

Used a chemical mass balance approach

Two-end members for solids (CSO and Harbor)

Two chemicals – Pb & Al.

Results showed CSO on average contribute ~ 30 percent of solids.

Given the uncertainties, this is consistent with bathymetry observations, i.e., the harbor is the main source of solids

Further statistical analysis is being conducted to determine uncertainty in estimate.

41

Total PAHs in Surface Sediments vs. CSO Wet Weather Solids

1

10

100

1000

10000

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Tota

l PAH

(mg/

kg)


Total PAHs in Surface Sediments and CSO Wet Weather Solids

Reference

Surface Sediments

EPA PRG TPAH

NYCDEP Estimate of PRG CSO - Pipe Sediments

CSO - City Estimates

CSO - EPA Estimates

42

B(a)A in Surface Sediments vs. CSO Wet Weather Solids

0.01

0.1

1

10

100

1000

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Ben

zo(a

)Ant

hrac

ene

(mg/

kg)


Benzo(a)Anthracene in Surface Sediments and CSO Wet Weather Solids

Reference

Surface Sediments

CSO - Pipe Sediments


Non-Detect

CSO - EPA Estimates

43

B(a)P in Surface Sediments vs. CSO Wet Weather Solids

0.01

0.1

1

10

100

1000

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Ben

zo(a

)Ant

hrac

ene

(mg/

kg)


Benzo(a)Pyrene in Surface Sediments and CSO Wet Weather Solids

Reference

Surface Sediments



Non-Detect

CSO - EPA Estimates

44

B(b)F in Surface Sediments vs. CSO Wet Weather Solids

0.01

0.1

1

10

100

1000

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Ben

zo(b

)Flu

oran

then

e (m

g/kg

)


Benzo(b)Fluoranthene in Surface Sediments and CSO Wet Weather Solids

Reference

Surface Sediments



Non-Detect

CSO - EPA Estimates

45

Dibenzo(a,h)Anthracene in Surface Sediments vs. CSO Wet Weather Solids

0.01

0.1

1

10

100

1000

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Dib

enz(

A,H

)Ant

hrac

ene

(mg/

kg)


Dibenz(A,H)Anthracene in Surface Sediments and CSO Wet Weather Solids

Reference

Surface Sediments



Non-Detect

CSO - EPA Estimates

46

Acenaphthalene in Surface Sediments vs. CSO Wet Weather Solids

0.01

0.1

1

10

100

1000

10000

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Acen

apht

hyle

ne (m

g/kg

)


Acenaphthylene in Surface Sediments and CSO Wet Weather Solids

Reference

Surface Sediments



Non-Detect

CSO - EPA Estimates

47

Naphthalene in Surface Sediments vs. CSO Wet Weather Solids

0.01

0.1

1

10

100

1000

10000

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Nap

htha

lene

(mg/

kg)


Naphthalene in Surface Sediments and CSO Wet Weather Solids

Reference

Surface Sediments



Non-Detect

48

Impact of Groundwater on the Canal City’s Groundwater Flow Model Development indicates:

Based on site information and USGS publications

Agrees well with USGS head and flow data

The calibrated discharge to Gowanus Canal is about 2.1 ft3/sec (USGS pre-development estimate is 2.5 ft3/sec).

Model indicates about 75% of the flow to Gowanus Canal is through the sediment and 25% of flow is through the banks.

EPA has not accounted for the groundwater impact on the Canal for metals and PAHs.

49

Groundwater Loads to the Canal - PAHs

Analyte

Mean Concentration From Sampled

GW (ug/l)

Estimated Annual Load

from GW (Kg/yr)

Estimated Mean GW

Concentration* (ug/L)

Potential Annual Loads

from GW* (Kg/yr)

Mean CSO Aqueous

Concentration (ug/L)

CSO Loads (kg/yr)

CSO Loads (kg/yr) after CSO Order

Upgrades 34% Reduction in

CSO Discharge

Acenaphthene 946 1,750 0.67 0.96 0.63

Acenaphthylene 1,020 1,900 0.2 0.28 0.18

Anthracene 156 300 0.2 0.29 0.19

Benzo(a)anthracene 1.47 2.84 5.1 10 0.25 0.36 0.24

Benzo(a)pyrene 1.34 2.60 1.2 2*(1.2**) 0.25 0.36 0.24

Benzo(b)fluoranthene 0.82 1.60 0.7 1 0.35 0.5 0.33

Benzo(g,h,i)perylene 0.60 1.16 0.4 1 0.39 0.55 0.36

Benzo(k)fluoranthene 0.58 1.13 0.2 0.4 0.23 0.33 0.22

Chrysene 3 6 0.26 0.37 0.24

Dibenz(a,h)anthracene 0.14 0.27 9 17 0.24 0.34 0.22

Fluoranthene 34 65 0.34 0.48 0.32

Fluorene 429 800 0.29 0.41 0.27

Indeno(1,2,3-cd)pyrene 0.55 1.06 0.44 1 0.35 0.5 0.33

Naphthalene 1335 2590

26,925 50,500*

(7,500**) 4 5.7

3.8

Phenanthrene 33.4 64.7 412 770* (110**) 0.48 0.69 0.46

Pyrene 53 100 0.38 0.55 0.36

* - Based on effective solubility of NAPL ** - Based on results of SEAM3D groundwater contaminant fate and transport model

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Conclusions Eco PRG: Data are not robust enough to support a remedial decision

CSO data are not adequate to characterize their impact on the Canal

PAH partitioning behavior is highly uncertain

CSM fails to account for sediment deposition and mixing throughout the Canal

Data provides strong evidence for a significant contribution of harbor solids

CSM does not take groundwater into account

Surface sediment and CSO data indicate the occurrence of ongoing sources of B(a)P, Napthalene and other PAHs significantly greater than CSO contributions

Remedy does not prevent recontamination from groundwater discharges/ upwelling during cap construction and over the long term

Deep dredging impacts on DO are not considered.

Runs counter to the Eco PRG for protection of benthics

City proposes to fill data gaps

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Proposed SOW for Data Collection CSO characterization

‒ Dissolved and Solids Phase measurements of COPCs

‒ TSS

Eco toxicity testing

Impacts of MGP sites on CSOs due to Fulton MGP Site

• CCTV Investigation

• Sampling up and down gradient of MGP Sites

Solids balance in the Canal

• Radionuclide sampling in surface sediments of the Canal and Harbor

• Radionuclide sampling in TSS from the CSOs, Canal, and Harbor

• TSS in the Canal water column

• TSS in the Harbor

Chemical Balance in the Canal

• COPC sampling in recently deposited surface sediments of the Canal and Harbor

• COPC sampling water column for Canal and Harbor

NYCDEP is prepared to assist EPA to collect data on an expedited basis

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Questions?

gowanus canal fs tests are started more than 2 weeks after collection, it is desirable to conduct...

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