Page 1 of 26

MEMORANDUM

TO: Dan Buford and George Noguchi, Fish and Wildlife Service

Jennifer Schultz, Ron Dean, and Pat Shaw-Allen, NOAA

FROM: Ryan Albert and Jamie Piziali, Environmental Protection Agency

DATE: October 25, 2012

SUBJECT: Addendum to the Biological Evaluation for the 2013 Vessel General Permit 

(VGP) and Small Vessel General Permit (sVGP) - Correction for Antifouling Leachate and Selenium Discharges

This memorandum is an addendum to the Biological Evaluation (BE) for the 2013 VGP and 

sVGP to correct two issues in the Quantitative Effects Analysis (Section 5): copper loadings 

from anti-foulant hull coatings and selenium loadings from exhaust gas scrubbers. We 

appreciate the Services’ input and feedback regarding our biological evaluation, and have 

conducted supplementary analyses to further explore these issues. Regarding copper, in 

preparing the BE, EPA inadvertently excluded from its analysis pollutant loadings contributed by 

anti-fouling leachate discharges. This memo first describes copper loadings, updates those 

loadings, estimates concentrations of copper in harbors resulting from copper, and finally, briefly 

discusses impacts to our risk quotient analyses. Regarding selenium, EPA both grossly 

overestimated the numbers of vessels that would be using “open loop” exhaust gas scrubbers and 

there appears to be matrix interference in the selenium measurements used to calculate loadings. 

Beginning on page 19, we discuss the previous overestimates of selenium loadings and provide 

more accurate, updated estimates. Based on these supplemental analyses, we still conclude that

these pollutants are not likely to adversely affect listed species or critical habitat.

I. Copper

EPA describes copper leached from vessel anti-fouling coatings into receiving waters in Section 

3.2 (Vessel Discharges Meriting Detailed Analysis) of the BE. We then discuss the quantitative 

analysis performed for pollutants such as copper in Section 5.2.1 (Hypothetical Harbor and 

Estimation of Exposure Concentrations) and in Appendix G (Methodology for Hypothetical 

Harbor Modeling) of the BE.

EPA made the following errors in estimating copper loads discharged from vessel anti-fouling 

leachate and in the subsequent quantitative analysis:

Text on page 3-38 and Table 3-18 mistakenly exclude sVGP vessels;

Table 3-18 mistakenly omits an important clarification that few barges use anti-fouling 

coatings; and
Page 2 of 26

The quantitative analyses described in Section 5.2.1, Section 5.4.1, Section 5.4.2, and 

Appendix G mistakenly exclude copper loadings from vessel anti-fouling leachate.

a. Corrected Text on Page 3-38 and Corrected Table 3-18

Table 3-18 did not include the copper loadings which would originate from anti-foulant coatings 

on sVGP vessels and relevant text did not include discussion. The following paragraph replaces 

the final paragraph on page 3-38 of the BE:

Another source of copper is from anti-fouling coatings applied to the vessel hull to 

prevent biofouling. Copper can leach from anti-fouling coatings at rates ranging from 4 to 

17 μg/cm2/day1. To estimate the amount of copper leached from anti-fouling coatings on 

the various types of VGP and sVGP vessels, the average vessel length and draft (i.e., 

depth below the water line) was estimated and an average copper leaching rate applied. 

Table 3-18 shows the estimated daily amount of copper leached from VGP and sVGP 

vessel types. Copper leaching rates range from 0.0057 lbs/day for small commercial 

fishing vessels to up to 2.6 lbs/day for large oil and gas tankers.

The following table with sVGP vessels replaces Table 3-18 on page 3-40 of the BE (note there 

are no changes to VGP vessels in this table):

Table 3-18. Estimated Amount of Copper Leached from Anti-fouling Coatings Applied to 

Various Vessel Types

Vessel Type

Average 

Vessel 

Length (ft)

Estimated 

Vessel Draft

(ft)

Wetted 

Hull Area 

(ft2)

Average Copper 

Leaching Rate 

(μg/cm2/day)j

Estimated Copper 

Leaching Rate

(lbs/day/vessel)

Barges 175a10d3,500 10.5 0.075n

Oil and Gas Tankers 797b75e120,257 10.5 2.6

Large Commercial 

Fishing Vessels 250a

17f8,500 10.5 0.18

Large Cruise Ships 995c28g55,706 10.5 1.2

Large Ferries 200a15.5h6,200 10.5 0.13

Medium Cruise 

Ships 325a

15.5h10,075 10.5 0.22

Bulk Cargo and 

Other Carriers 663b

38i50,355 10.5 1.1

Small Commercial 

Fishing Vessels 33k

4

l

264 10.5 0.0057

Passenger Vessels 

(tour boats, water 

taxis, etc.)

45k4

m

360 10.5 0.0077

 

1 USEPA. 2011. Technical Development Document (TDD): Underwater Hull Husbandry, EPA800-R-11-004, November 2011.
Page 3 of 26

Table 3-18. Estimated Amount of Copper Leached from Anti-fouling Coatings Applied to 

Various Vessel Types

Vessel Type

Average 

Vessel 

Length (ft)

Estimated 

Vessel Draft

(ft)

Wetted 

Hull Area 

(ft2)

Average Copper 

Leaching Rate 

(μg/cm2/day)j

Estimated Copper 

Leaching Rate

(lbs/day/vessel)

Utility Vessels (tug 

boats, off-shore 

vessels, etc.)

50k4

m

400 10.5 0.0086

a) Average length estimated from Figure 1.3 of USEPA’s Report to Congress (USEPA, 2010).

b) Average length for oil tankers and bulk cargo carriers from Chamber of Shipping of America, MSD Survey, 2010.

c) Average cruise ship length calculated from the following cruise ships: Carnival Freedom, Disney Magic, Golden Princess 

and Freedom of the Sea.

d) Estimated draft for barges based on Barge Number 4727, Ingram, Nashville, TN.

e) Estimated draft for oil and gas tankers based on a Suezmax tanker, 

http://people.hofstra.edu/geotrans/eng/ch5en/appl5en/tankers.html

f) Estimated draft for large commercial fishing boats based on trawlers, http://maritimesales.com/fishing%20vessels.htm

g) Estimated draft for large cruise ships based on Royal Caribbean Freedom of the Seas.

h) Estimated draft for large ferries and medium cruise ships based on Washington State Department of Transportation’s M/V 

Sealth, passenger/auto ferry.

i) Estimated draft for bulk cargo vessels based on Golden Pegasus Navigation S.A High Glow vessel.

j) Average copper leaching rate from USEPA Underwater Ship Husbandry Discharges, (USEPA, 2011f).

k) Average length estimated from Figure 1.5 of USEPA’s Report to Congress (USEPA, 2010).

l) Estimated draft for small commercial fishing boats 30 to 40 feet in length, http://pacificboatbrokers.com/fishing/licvess.asp.

m) Estimated draft for various passenger and utility vessels, http://www.taxi-boat.com/, http://commercial.apolloduck.com/, 

http://allmandboats.com/.

n) Per EPA’s Notice of Intent database, very few barges use anti-fouling coatings. EPA assumes these barges are engaged in 

coastwise trade of bulk cargo.
Page 4 of 26

b. Corrected Loads and Harbor Concentrations Analyses

The following table replaces Table G-8 on page G-75 of the BE:

Table G-8. Total VGP and sVGP Pollutant Loads for RAA Harbors Under Pre-permit

Class Analyte

Estuary Harbor Loads (lb/day) River Harbor Loads (lb/day)

Seattle Houston

New 

York San Fran Miami Duluth St. Louis

Classicals Biochemical Oxygen Demand (BOD) 21,000 1,100 8,970 3,540 4,960 161 180

Classicals Hexane Extractable Material (HEM) 1,430 255 1,510 703 1,460 14.1 16.7

Classicals Silica Gel Treated HEM (SGT-HEM) 389 76.9 372 182 371 3.72 4.19

Classicals Total Residual Chlorine 49.3 0.561 4.6 1.08 1.65 0.0537 0.0642

Classicals Total Suspended Solids (TSS) 4,650 589 1,720 831 1,070 40.1 45.6

Metals Aluminum, Total 29.5 9.97 19.5 9.51 13.8 0.513 0.653

Metals Arsenic, Dissolved 8.47 44.5 39.1 26.1 20.1 3.21 0

Metals Arsenic, Total 8.65 44.5 39.1 26.2 20.2 3.21 0.000734

Metals Cadmium, Dissolved 0.0199 0.00449 0.00589 0.00378 0.00425 0.000207 0.000252

Metals Chromium, Dissolved 0.044 0.0142 0.0157 0.0103 0.00991 0.00078 0.000449

Metals Copper, Dissolved 24.2 68.7 54.9 31.4 23.8 3.21 0.43

Metals Lead, Dissolved 0.066 0.0203 0.0678 0.0267 0.0437 0.00143 0.0018

Metals Nickel, Dissolved 1.26 6.69 5.9 3.93 3.06 0.481 0.00107

Metals Nickel, Total 0.115 0.256 0.288 0.169 0.203 0.0141 0.00227

Metals Selenium, Dissolved **   **  ** ** 0

Metals Selenium, Total   **  **   0
Page 5 of 26

Table G-8. Total VGP and sVGP Pollutant Loads for RAA Harbors Under Pre-permit

Class Analyte

Estuary Harbor Loads (lb/day) River Harbor Loads (lb/day)

Seattle Houston

New 

York San Fran Miami Duluth St. Louis

Metals Zinc, Dissolved 11.3 1.43 8.58 3.12 5.05 0.157 0.189

Nutrients Ammonia As Nitrogen (NH3-N) 219 4.06 36.8 21.5 21.7 0.626 0.53

Nutrients Total Phosphorus 273 19.7 96 56.3 98.8 0.886 0.859

SVOC 2,4,6-Trichlorophenol 0.0236 0.00363 0.00393 0.00294 0.0021 0.000198 0.000221

SVOC Benzo(a)anthracene 0.158 0.156 0.142 0.0972 0.069 0.0156 0.00521

SVOC Benzo(a)pyrene 0.141 0.0862 0.0808 0.0562 0.0375 0.0105 0.00505

SVOC Benzo(b)fluoranthene 0.112 0.0101 0.0133 0.0108 0.00325 0.00445 0.00442

SVOC Benzo(k)fluoranthene 0.124 0.0111 0.0147 0.012 0.0036 0.00493 0.00489

SVOC Bis(2-ethylhexyl) phthalate 0.131 0.0285 0.0349 0.023 0.0213 0.00376 0.00387

SVOC Chrysene 0.169 0.217 0.196 0.133 0.0965 0.02 0.00521

SVOC Ideno(1,2,3-cd)pyrene 0.0997 0.00899 0.0118 0.00966 0.0029 0.00398 0.00395

VOC Benzene 0.716 0.11 0.136 0.0964 0.069 0.0222 0.0228

VOC Bromodichloromethane 0.0319 0.035 0.0448 0.0243 0.0368 0.00143 0.00192

VOC Dibromochloromethane 0.0319 0.035 0.0448 0.0243 0.0368 0.00143 0.00192

VOC Tetrachloroethene 0.000263 0.000588 0.000662 0.000388 0.000465 0.0000324 0.00000521

VOC Trichloroethene 0.992 26.2 4.81 0.215 0.222 0.0000737 4.63

** Note that Selenium values have been removed and are discussed later in this memo.
Page 6 of 26

The following table replaces Table G-9 on page G-76 of the BE:

Table G-9. Total VGP and sVGP Pollutant Loads for RAA Harbors Under Post-permit Conditions

Class Analyte

Estuary Harbor Loads (lb/day) River Harbor Loads (lb/day)

Seattle Houston

New 

York San Fran Miami Duluth St. Louis

Classicals Biochemical Oxygen Demand (BOD) 15,500 930 8,580 3,130 4,770 146 178

Classicals Hexane Extractable Material (HEM) 718 123 745 345 721 5.5 6.08

Classicals Silica Gel Treated HEM (SGT-HEM) 205 37.7 184 89.6 182 1.55 1.64

Classicals Total Residual Chlorine 15.2 0.417 3.02 0.937 1.46 0.0456 0.0623

Classicals Total Suspended Solids (TSS) 2,980 263 1,250 519 703 24.2 31.8

Metals Aluminum, Total 23.5 6.43 14.5 6.26 9 0.323 0.603

Metals Arsenic, Dissolved 8.35 44.5 39.1 26.1 20.1 3.21 0

Metals Arsenic, Total 8.5 44.5 39.1 26.2 20.2 3.21 0.000734

Metals Cadmium, Dissolved 0.016 0.00281 0.00359 0.00225 0.00216 0.000116 0.000231

Metals Chromium, Dissolved 0.0426 0.012 0.0134 0.00886 0.00816 0.000661 0.000434

Metals Copper, Dissolved 19.0 53.6 43.2 24.8 18.9 2.57 0.336

Metals Lead, Dissolved 0.0602 0.014 0.0591 0.0212 0.0353 0.00109 0.00172

Metals Nickel, Dissolved 1.23 6.68 5.89 3.93 3.05 0.481 0.00106

Metals Nickel, Total 0.115 0.256 0.288 0.169 0.203 0.0141 0.00227

Metals Selenium, Dissolved **   **  ** ** 0

Metals Selenium, Total   **  **   0

Metals Zinc, Dissolved 10.4 1.11 8.14 2.83 4.66 0.139 0.185

Nutrients Ammonia As Nitrogen (NH3-N) 171 3.67 34.7 18.8 21.4 0.558 0.528
Page 7 of 26

Table G-9. Total VGP and sVGP Pollutant Loads for RAA Harbors Under Post-permit Conditions

Class Analyte

Estuary Harbor Loads (lb/day) River Harbor Loads (lb/day)

Seattle Houston

New 

York San Fran Miami Duluth St. Louis

Nutrients Total Phosphorus 12.5 1.22 2.28 1.32 1.11 0.0767 0.116

SVOC 2,4,6-Trichlorophenol 0.0118 0.00228 0.00219 0.00149 0.00106 0.0000992 0.000193

SVOC Benzo(a)anthracene 0.158 0.156 0.142 0.0972 0.069 0.0156 0.00521

SVOC Benzo(a)pyrene 0.141 0.0862 0.0808 0.0562 0.0375 0.0105 0.00505

SVOC Benzo(b)fluoranthene 0.112 0.0101 0.0133 0.0108 0.00325 0.00445 0.00442

SVOC Benzo(k)fluoranthene 0.124 0.0111 0.0147 0.012 0.0036 0.00493 0.00489

SVOC Bis(2-ethylhexyl) phthalate 0.0976 0.0159 0.0186 0.0127 0.00842 0.0031 0.00342

SVOC Chrysene 0.169 0.217 0.196 0.133 0.0965 0.02 0.00521

SVOC Ideno(1,2,3-cd)pyrene 0.0997 0.00899 0.0118 0.00966 0.0029 0.00398 0.00395

VOC Benzene 0.593 0.0739 0.0891 0.0657 0.0326 0.0203 0.0215

VOC Bromodichloromethane 0.011 0.0109 0.0132 0.00638 0.00935 0.000368 0.000865

VOC Dibromochloromethane 0.011 0.0109 0.0132 0.00638 0.00935 0.000368 0.000865

VOC Tetrachloroethene 0.000132 0.000294 0.000331 0.000194 0.000233 0.0000162 0.00000261

VOC Trichloroethene 0.00439 0.000847 0.000814 0.000552 0.000395 0.0000368 0.0000716

** Note that Selenium values have been removed and are discussed later in this memo.
Page 8 of 26

In order to provide the best information regarding potential sources of copper loadings from vessels, we have added two tables below 

describing what we believe to be the primary vessel types and discharge streams which result in copper source loadings. Tables 1 and 

2 below present the revised dissolved copper loadings by wastestream for each of the harbor scenarios. These revised loadings 

increased the estimated dissolved copper receiving water concentrations for the 14 hypothetical harbor scenarios evaluated in the BE.

Table 1. Pre-Permit Dissolved Copper Loads by Wastestream for Harbor Scenarios

Permit Vessel Type Discharge Type

Estuary Harbor Loads (lb/day)

River Harbor Loads 

(lb/day)

Seattle Houston New York San Fran Miami Duluth St. Louis

VGP Oil/Gas Tankers Antifouling 0.243 47.5 14 7.59 0 0 0

VGP Cargo/Bulk Carrier Antifouling 3.14 11 18.9 13.6 10 2.29 0

VGP Oil/Gas Tankers Exhaust Gas Scrubber (Saltwater) 0.0267 5.22 1.54 0.834 0 0 0

VGP Cargo/Bulk Carrier Exhaust Gas Scrubber (Saltwater) 0.816 2.86 4.9 3.52 2.6 0.594 0

VGP Large Cruise Ship Antifouling 4.8 1.2 6 3.6 8.4 0 0

sVGP Utility Boats Antifouling 0.0516 0.367 0.249 0.14 0.066 0.141 0.14

VGP Large Cruise Ship Exhaust Gas Scrubber (Saltwater) 0.643 0.161 0.804 0.482 1.13 0 0

VGP Large Cruise Ship Graywater 0.285 0.0714 0.357 0.214 0.499 0 0

sVGP Utility Boats Wet Exhaust (Propulsion) 0.00768 0.0547 0.037 0.0209 0.00982 0.021 0.0209

VGP Oil/Gas Tankers Deck Washdown 0.000269 0.0527 0.0155 0.0084 0 0 0

VGP Barge Deck Washdown 0.00104 0.0276 0.00507 0.000225 0.000234 0 0.00489

VGP Oil/Gas Tankers Bilgewater 0.00013 0.0253 0.00747 0.00404 0 0 0

VGP Cargo/Bulk Carrier Deck Washdown 0.00527 0.0184 0.0316 0.0227 0.0168 0.00384 0

VGP Large Cruise Ship Deck Washdown 0.0566 0.0142 0.0708 0.0425 0.0991 0 0

VGP Barge Bilgewater 0.000501 0.0133 0.00245 0.000109 0.000113 0 0.00236

VGP Cargo/Bulk Carrier Bilgewater 0.00253 0.00887 0.0152 0.0109 0.00808 0.00185 0

VGP Oil/Gas Tankers Graywater 0.0000425 0.00831 0.00245 0.00133 0 0 0

VGP Oil/Gas Tankers Stern Tube Packing Gland 0.0000321 0.00627 0.00185 0.001 0 0 0

sVGP Utility Boats Graywater 0.000743 0.00529 0.00358 0.00202 0.000951 0.00204 0.00202

VGP Cargo/Bulk Carrier Graywater 0.00148 0.00516 0.00885 0.00636 0.0047 0.00107 0

VGP Large Cruise Ship Bilgewater 0.0119 0.00298 0.0149 0.00894 0.0209 0 0

sVGP Utility Boats Wet Exhaust (Generator) 0.000381 0.00271 0.00183 0.00103 0.000486 0.00104 0.00103

VGP Cargo/Bulk Carrier Stern Tube Packing Gland 0.000627 0.00219 0.00376 0.0027 0.002 0.000456 0

sVGP Utility Boats Bilgewater 0.000185 0.00132 0.000892 0.000503 0.000237 0.000508 0.000503
Page 9 of 26

Table 1. Pre-Permit Dissolved Copper Loads by Wastestream for Harbor Scenarios

Permit Vessel Type Discharge Type

Estuary Harbor Loads (lb/day)

River Harbor Loads 

(lb/day)

Seattle Houston New York San Fran Miami Duluth St. Louis

sVGP Passenger Vessel Antifouling 0.115 0.000749 0.077 0.0341 0.038 0.0127 0.0154

VGP Large Cruise Ship Stern Tube Packing Gland 0.00295 0.000737 0.00368 0.00221 0.00516 0 0

sVGP Passenger Vessel Graywater 0.0872 0.000567 0.0582 0.0258 0.0288 0.00957 0.0116

sVGP Utility Boats Deck Washdown 0.0000294 0.000209 0.000142 0.00008 0.0000376 0.0000807 0.00008

sVGP Passenger Vessel Wet Exhaust (Propulsion) 0.0217 0.000141 0.0145 0.0064 0.00714 0.00238 0.00289

sVGP Utility Boats Stern Tube Packing Gland 6.61E-06 0.000047 0.0000318 0.000018 0.00000845 0.0000181 0.000018

sVGP Passenger Vessel Wet Exhaust (Generator) 0.00341 0.0000221 0.00228 0.00101 0.00112 0.000374 0.000455

sVGP Passenger Vessel Bilgewater 0.000275 1.79E-06 0.000184 0.0000813 0.0000906 0.0000302 0.0000367

sVGP Passenger Vessel Deck Washdown 0.000142 9.21E-07 0.0000946 0.0000419 0.0000467 0.0000156 0.0000189

sVGP Passenger Vessel Stern Tube Packing Gland 7.15E-06 4.64E-08 4.77E-06 2.11E-06 0.00000236 0.000000785 0.000000955

VGP Commercial Fishing Stern Tube Packing Gland 0.000009 0 3.67E-07 0 0 0 0

VGP Barge Antifouling 0 0 0 0 0 0 0

VGP Medium Cruise Ship Exhaust Gas Scrubber (Saltwater) 0 0 0 0 0 0 0

VGP Barge Graywater 0 0 0 0 0 0 0

VGP Commercial Fishing Bilgewater 0.00767 0 0.000313 0 0 0 0

VGP Commercial Fishing Deck Washdown 0.000884 0 0.0000361 0 0 0 0

VGP Commercial Fishing Graywater 0.0147 0 0.000599 0 0 0 0

VGP Commercial Fishing Fish Hold Cleaning 0.0012 0 0.0000489 0 0 0 0

VGP Large Ferry Stern Tube Packing Gland 0.0000793 0 0.000991 0.0000815 0.0000815 0 0

sVGP Commercial Fishing Wet Exhaust (Propulsion) 0.556 0 0.0185 0.0299 0 0.000556 0

sVGP Commercial Fishing Antifouling 5.7 0 0.19 0.306 0 0.0057 0

sVGP Commercial Fishing Graywater 0.599 0 0.02 0.0322 0 0.000599 0

sVGP Commercial Fishing Stern Tube Packing Gland 0.000367 0 0.0000122 0.0000197 0 0.000000367 0

sVGP Commercial Fishing Bilgewater 0.313 0 0.0104 0.0168 0 0.000313 0

sVGP Commercial Fishing Deck Washdown 0.0361 0 0.0012 0.00194 0 0.0000361 0

VGP Large Ferry Deck Washdown 0.00152 0 0.019 0.00156 0.00156 0 0

VGP Large Ferry Graywater 0.0462 0 0.577 0.0474 0.0474 0 0

VGP Commercial Fishing Fish Hold 0.0309 0 0.00126 0 0 0 0

VGP Large Ferry Exhaust Gas Scrubber (Saltwater) 0 0 0 0 0 0 0

VGP Commercial Fishing Antifouling 4.41 0 0.18 0 0 0 0
Page 10 of 26

Table 1. Pre-Permit Dissolved Copper Loads by Wastestream for Harbor Scenarios

Permit Vessel Type Discharge Type

Estuary Harbor Loads (lb/day)

River Harbor Loads 

(lb/day)

Seattle Houston New York San Fran Miami Duluth St. Louis

VGP Large Ferry Antifouling 0.52 0 6.5 0.534 0.534 0 0

sVGP Commercial Fishing Fish Hold 1.26 0 0.042 0.0677 0 0.00126 0

sVGP Commercial Fishing Fish Hold Cleaning 0.0489 0 0.00163 0.00263 0 0.0000489 0

VGP Medium Cruise Ship Deck Washdown 0.00121 0 0.00121 0.00121 0.00121 0.000657 0.00121

VGP Medium Cruise Ship Stern Tube Packing Gland 0.000063 0 0.000063 0.000063 0.000063 0.0000341 0.000063

VGP Medium Cruise Ship Graywater 0.00651 0 0.00651 0.00651 0.00651 0.00352 0.00651

sVGP Commercial Fishing Wet Exhaust (Generator) 0.0497 0 0.00166 0.00267 0 0.0000497 0

VGP Medium Cruise Ship Bilgewater 0.000255 0 0.000255 0.000255 0.000255 0.000138 0.000255

VGP Medium Cruise Ship Antifouling 0.22 0 0.22 0.22 0.22 0.119 0.22

VGP Large Ferry Bilgewater 0.000324 0 0.00405 0.000333 0.000333 0 0

Total Dissolved Copper Load 24.2 68.7 54.9 31.4 23.8 3.21 0.43

Table 2. Post-Permit Dissolved Copper Loads by Wastestream for Harbor Scenarios

Permit Vessel Type Discharge Type

Estuary Harbor Loads (lb/day)

River Harbor Loads 

(lb/day)

Seattle Houston New York San Fran Miami Duluth St. Louis

VGP Oil/Gas Tankers Antifouling 0.182 35.7 10.5 5.69 0 0 0

VGP Cargo/Bulk Carrier Antifouling 2.36 8.25 14.1 10.2 7.52 1.72 0

VGP Oil/Gas Tankers Exhaust Gas Scrubber (Saltwater) 0.0267 5.22 1.54 0.834 0 0 0

VGP Cargo/Bulk Carrier Exhaust Gas Scrubber (Saltwater) 0.816 2.86 4.9 3.52 2.6 0.594 0

VGP Large Cruise Ship Antifouling 3.6 0.9 4.5 2.7 6.3 0 0

sVGP Utility Boats Antifouling 0.0387 0.275 0.186 0.105 0.0495 0.106 0.105

VGP Large Cruise Ship Exhaust Gas Scrubber (Saltwater) 0.643 0.161 0.804 0.482 1.13 0 0

VGP Large Cruise Ship Graywater 0.285 0.0714 0.357 0.214 0.499 0 0

sVGP Utility Boats Wet Exhaust (Propulsion) 0.00768 0.0547 0.037 0.0209 0.00982 0.021 0.0209

VGP Barge Deck Washdown 0.00104 0.0276 0.00507 0.000225 0.000234 0 0.00489
Page 11 of 26

Table 2. Post-Permit Dissolved Copper Loads by Wastestream for Harbor Scenarios

Permit Vessel Type Discharge Type

Estuary Harbor Loads (lb/day)

River Harbor Loads 

(lb/day)

Seattle Houston New York San Fran Miami Duluth St. Louis

VGP Oil/Gas Tankers Deck Washdown 0.000135 0.0263 0.00776 0.0042 0 0 0

VGP Barge Bilgewater 0.000501 0.0133 0.00245 0.000109 0.000113 0 0.00236

VGP Oil/Gas Tankers Bilgewater 0.0000648 0.0127 0.00373 0.00202 0 0 0

VGP Cargo/Bulk Carrier Deck Washdown 0.00263 0.00921 0.0158 0.0114 0.0084 0.00192 0

VGP Large Cruise Ship Deck Washdown 0.0283 0.00708 0.0354 0.0212 0.0496 0 0

VGP Oil/Gas Tankers Stern Tube Packing Gland 0.0000321 0.00627 0.00185 0.001 0 0 0

VGP Oil/Gas Tankers Graywater 0.0000319 0.00623 0.00184 0.000994 0 0 0

sVGP Utility Boats Graywater 0.000743 0.00529 0.00358 0.00202 0.000951 0.00204 0.00202

VGP Cargo/Bulk Carrier Bilgewater 0.00127 0.00443 0.0076 0.00547 0.00404 0.000923 0

VGP Cargo/Bulk Carrier Graywater 0.00111 0.00387 0.00664 0.00477 0.00353 0.000806 0

sVGP Utility Boats Wet Exhaust (Generator) 0.000381 0.00271 0.00183 0.00103 0.000486 0.00104 0.00103

VGP Cargo/Bulk Carrier Stern Tube Packing Gland 0.000627 0.00219 0.00376 0.0027 0.002 0.000456 0

VGP Large Cruise Ship Bilgewater 0.00596 0.00149 0.00745 0.00447 0.0104 0 0

sVGP Utility Boats Bilgewater 0.000185 0.00132 0.000892 0.000503 0.000237 0.000508 0.000503

VGP Large Cruise Ship Stern Tube Packing Gland 0.00295 0.000737 0.00368 0.00221 0.00516 0 0

sVGP Passenger Vessel Graywater 0.0872 0.000567 0.0582 0.0258 0.0288 0.00957 0.0116

sVGP Passenger Vessel Antifouling 0.0865 0.000562 0.0578 0.0256 0.0285 0.00949 0.0116

sVGP Utility Boats Deck Washdown 0.0000294 0.000209 0.000142 0.00008 0.0000376 0.0000807 0.00008

sVGP Passenger Vessel Wet Exhaust (Propulsion) 0.0217 0.000141 0.0145 0.0064 0.00714 0.00238 0.00289

sVGP Utility Boats Stern Tube Packing Gland 6.61E-06 0.000047 0.0000318 0.000018

0.0000084

5 0.0000181 0.000018

sVGP Passenger Vessel Wet Exhaust (Generator) 0.00341 0.0000221 0.00228 0.00101 0.00112 0.000374 0.000455

sVGP Passenger Vessel Bilgewater 0.000275 1.79E-06 0.000184 0.0000813 0.0000906 0.0000302 0.0000367

sVGP Passenger Vessel Deck Washdown 0.000142 9.21E-07 0.0000946 0.0000419 0.0000467 0.0000156 0.0000189

sVGP Passenger Vessel Stern Tube Packing Gland 7.15E-06 4.64E-08 4.77E-06 2.11E-06

0.0000023

6

0.00000078

5

0.0000009

55

VGP Commercial Fishing Deck Washdown 0.000442 0 0.000018 0 0 0 0
Page 12 of 26

Table 2. Post-Permit Dissolved Copper Loads by Wastestream for Harbor Scenarios

Permit Vessel Type Discharge Type

Estuary Harbor Loads (lb/day)

River Harbor Loads 

(lb/day)

Seattle Houston New York San Fran Miami Duluth St. Louis

VGP Barge Antifouling 0 0 0 0 0 0 0

VGP Commercial Fishing Graywater 0.011 0 0.000449 0 0 0 0

VGP Commercial Fishing Fish Hold 0.00771 0 0.000315 0 0 0 0

VGP Commercial Fishing Bilgewater 0.00383 0 0.000156 0 0 0 0

VGP Commercial Fishing Antifouling 3.31 0 0.135 0 0 0 0

VGP Commercial Fishing Stern Tube Packing Gland 0.000009 0 3.67E-07 0 0 0 0

VGP Large Ferry Exhaust Gas Scrubber (Saltwater) 0 0 0 0 0 0 0

sVGP Commercial Fishing Fish Hold Cleaning 0.0367 0 0.00122 0.00197 0 0.0000367 0

sVGP Commercial Fishing Deck Washdown 0.0361 0 0.0012 0.00194 0 0.0000361 0

sVGP Commercial Fishing Antifouling 4.28 0 0.143 0.23 0 0.00428 0

sVGP Commercial Fishing Fish Hold 0.944 0 0.0315 0.0508 0 0.000944 0

sVGP Commercial Fishing Wet Exhaust (Propulsion) 0.556 0 0.0185 0.0299 0 0.000556 0

sVGP Commercial Fishing Stern Tube Packing Gland 0.000367 0 0.0000122 0.0000197 0

0.00000036

7 0

sVGP Commercial Fishing Bilgewater 0.313 0 0.0104 0.0168 0 0.000313 0

sVGP Commercial Fishing Graywater 0.599 0 0.02 0.0322 0 0.000599 0

sVGP Commercial Fishing Wet Exhaust (Generator) 0.0497 0 0.00166 0.00267 0 0.0000497 0

VGP Medium Cruise Ship Exhaust Gas Scrubber (Saltwater) 0 0 0 0 0 0 0

VGP Large Ferry Deck Washdown 0.00152 0 0.019 0.00156 0.00156 0 0

VGP Commercial Fishing Fish Hold Cleaning 0.000299 0 0.0000122 0 0 0 0

VGP Large Ferry Stern Tube Packing Gland 0.0000793 0 0.000991 0.0000815 0.0000815 0 0

VGP Large Ferry Antifouling 0.39 0 4.88 0.401 0.401 0 0

VGP Large Ferry Bilgewater 0.000324 0 0.00405 0.000333 0.000333 0 0

VGP Barge Graywater 0 0 0 0 0 0 0

VGP Medium Cruise Ship Graywater 0.00651 0 0.00651 0.00651 0.00651 0.00352 0.00651

VGP Medium Cruise Ship Stern Tube Packing Gland 0.000063 0 0.000063 0.000063 0.000063 0.0000341 0.000063

VGP Medium Cruise Ship Antifouling 0.165 0 0.165 0.165 0.165 0.0894 0.165
Page 13 of 26

Table 2. Post-Permit Dissolved Copper Loads by Wastestream for Harbor Scenarios

Permit Vessel Type Discharge Type

Estuary Harbor Loads (lb/day)

River Harbor Loads 

(lb/day)

Seattle Houston New York San Fran Miami Duluth St. Louis

VGP Medium Cruise Ship Bilgewater 0.000127 0 0.000127 0.000127 0.000127 0.0000689 0.000127

VGP Medium Cruise Ship Deck Washdown 0.000606 0 0.000606 0.000606 0.000606 0.000329 0.000606

VGP Large Ferry Graywater 0.0462 0 0.577 0.0474 0.0474 0 0

Total Dissolved Copper Load 19 53.6 43.2 24.8 18.9 2.57 0.336
Page 14 of 26

Tables 3 and 4 below present the revised results of the dissolved copper concentrations for each 

of the scenarios evaluated in the BE. Across the 10 estuarine scenarios, the increase in loading 

due to hull fouling results in an average modeled copper concentration of 0.78 μg/L which is 

attributable to total vessel loading. In the 4 freshwater scenarios, the average concentration is 

0.037 μg/L. The maximum concentration in any scenario is in Scenario 2 with an in-water body 

concentration of 2.99 μg/L resulting from vessel discharges in the “pre-permit” state and 2.33 

μg/L in the post permit state. This scenario has the low flushing rate of a port such as Miami,

but the high vessel traffic from a port such as Houston. Hence, it is our belief that this scenario 

exceeds a worst case scenario. In comparison, Scenario 5 is a more realistic scenario with a 

simulating the Miami harbor with Miami vessel population, with an in-water body concentration 

of 0.82 μg/L in the post permit state.

Table 3. Dissolved Copper Concentrations (μg/L) in Hypothetical Estuarine Harbors 

Evaluated in the BE

Permit Condition

Scenario 1Scenario 2Scenario 3Scenario 4Scenario 5Scenario 6Scenario 7Scenario 8Scenario 9Scenario 10

Pre-Permit 1.05 2.99 2.39 1.37 1.03 0.14 0.39 0.31 0.18 0.14

Post-Permit 0.82 2.33 1.88 1.08 0.82 0.11 0.31 0.25 0.14 0.11

Table 4. Dissolved Copper Concentrations (μg/L) in Hypothetical River Harbors Evaluated 

in the BE

Permit Condition Scenario 11 Scenario 12 Scenario 13 Scenario 14

Pre-permit 0.164 0.022 0.001013 0.000136

Post-permit 0.131 0.017 0.000810 0.000106

c. Corrected Quantitative Effects Analysis

The revised dissolved copper loading estimates that include antifouling loads will change the 

estimated risk quotients (RQs) presented in Sections 5.3.2.5, 5.4.1, and 5.4.2.; however, EPA 

estimates that the risks under post-permit conditions will remain within the range of “remote” to 

“negligible” for all benchmarks evaluated in Section 5.3.2.5. EPA also estimates that mixtures of 

metals (Section 5.4.1) will also remain within the range of “remote” to “negligible” risk to listed 

species. 

Although the RQ for copper exceeds 1 when applying a safety adjustment factor of 2.0 to the 

Agency’s criterion continuous concentration (CCC) in two of the fourteen modeled scenarios,

EPA believes that the revised dissolved copper loadings do not change the Agency’s ultimate 

determination presented in Section 7.3 that for traditional pollutants VGP and sVGP vessel 
Page 15 of 26

discharges are “Not Likely to Adversely Affect” listed species. In the safety factor analysis, EPA 

selected the maximum concentration for comparison with half of the CCC benchmark. As 

previously mentioned, only two of the fourteen scenarios modeled in the BE exceed the safety 

factor benchmark and are classified as “potentially significant” under post-permit conditions. 

The remaining twelve scenarios all predict a “remote” or “negligible” risk to listed species. The 

dissolved copper loadings are driven by the presence of oil and gas tankers, bulk cargo and other 

carriers, and large cruise ships within a harbor. All three of these vessel types have significantly 

large surface areas that contribute to large loading rates. The number of ports within the United 

States that have large populations of these vessels types present at one time are limited and many 

of the ports with the largest populations of these vessel types were already included in the BE 

(e.g., Houston, New York, and Miami). The likelihood of a port with the receiving water 

characteristics of the hypothetical harbor scenario 1 containing vessel populations equivalent to 

Scenarios 2 and 3 (i.e., Houston and New York) is low. 

The remainder of this section presents the revised RQ values for the maximum dissolved copper 

concentration predicted in the hypothetical harbor modeling analysis.

The following table replaces Table 5-32 on page 5-95 of the BE:

Table 5-32. Risk Quotients Based on Division of Pre- and Post-permit Maximum 

Exposure Concentrations by Chronic Toxicity Thresholds of Representative Surrogate 

Taxa to Dissolved Copper

Taxa

ECW

(Pre-Permit

Condition);

(μg/L)

ECW

(Post-Permit

Condition);

(μg/L)

CTETA,W

(μg/L)

RQ

(PrePermit)

RQ

(PostPermit)

Freshwater Vertebrate

0.164 0.131

4.690 0.035 0.028

Freshwater Invertebrate 3.899 0.0422 0.0337

Freshwater plant (Vascular) 114.2 0.00144 0.00115

Estuarine/Marine Vertebrate

2.99 2.33

206.7 0.0144 0.0113

Estuarine/Marine Invertebrate 7.900 0.378 0.295

Saltwater plant (Vascular) 49.80 0.06 0.0468

Taxa

ECT

(Pre-Permit

Condition);

(mg/kg wet wt.)

ECT

(Post-Permit

Condition);

(mg/kg wet wt.)

CTETA,T

(mg/kg wet 

wt.)

RQ

(PrePermit)

RQ

(PostPermit)

Freshwater Vertebrate

0.0477 0.0381

3.00 0.0159 0.0127

Freshwater Invertebrate 3.80 0.0125 0.01

Freshwater plant (Vascular) NA 0.189 0.147

Estuarine/Marine Vertebrate

0.866 0.676

4.59 0.222 0.173

Estuarine/Marine Invertebrate 3.90 0.0159 0.0127
Page 16 of 26

Table 5-32. Risk Quotients Based on Division of Pre- and Post-permit Maximum 

Exposure Concentrations by Chronic Toxicity Thresholds of Representative Surrogate 

Taxa to Dissolved Copper

Saltwater plant (Vascular) NA 0.0125 0.01

Taxa

ECO

(Pre-Permit

Condition);

(mg/kg bw/d)

ECO

(Post-Permit

Condition);

(mg/kg bw/d)

CTETO

(mg/kg bw/d)

RQ

(PrePermit)

RQ

(PostPermit)

Mammals (Freshwater) 0.00655 0.00523 11.7 0.00056 0.000447

Birds (Freshwater) 0.0361 0.0289 47.0 0.000769 0.000614

Mammals (Saltwater) 0.119 0.0926 11.7 0.0101 0.00791

Birds (Saltwater) 0.656 0.512 47.0 0.014 0.0109

The following table replaces Table 5-56 on page 5-141 of the BE:

Table 5-56. Summary of Species-Specific Risk Conclusions for Listed Aquatic and 

Aquatic-dependent Species in RAAs

Pollutant

ECW

(Pre-Permit

Condition)

(μg/L)

ECW

(Post-Permit

Condition)

(μg/L)

CCC/2.0b

(μg/L)

RQ

(PrePermit)

RQ

(PostPermit)

Freshwater

Total Residual Chlorine 0.00328 0.00319 5.5 0.000597 0.00058

Aluminum, Total 0.0334 0.0309 44 0.000759 0.000701

Arsenic, Dissolved 0.164 0.164 75 0.00219 0.00219

Cadmium, Dissolved 0.0000129 0.0000118 1.1 <0.0001 <0.0001

Chromium, Dissolved 0.0000399 0.0000338 5.5 <0.0001 <0.0001

Copper, Dissolved 0.164 0.131 1.5c0.11 0.0876

Lead, Dissolved 0.0000922 0.0000878 1.3 <0.0001 <0.0001

Nickel, Dissolved 0.0246 0.0246 26 0.000946 0.000945

Selenium, Total ** ** 2

d

 

Zinc, Dissolved 0.00968 0.00948 60 0.000161 0.000158

Total Ammonia Nitrogen 0.000032a0.0000285a0.28a0.000114 0.000102

Saltwater

Total Residual Chlorine 2.14 0.66 3.8 0.564 0.174

Aluminum, Total 1.28 1.02 - <0.0001 <0.0001

Arsenic, Dissolved 1.94 1.94 18 0.108 0.108

Cadmium, Dissolved 0.000867 0.000697 4.7 0.000184 0.000148

Chromium, Dissolved 0.00191 0.00185 25 <0.0001 <0.0001

Copper, Dissolved 2.99 2.33 1.6 1.87 1.46

Lead, Dissolved 0.00295 0.00262 4.1 0.000719 0.000639

Nickel, Dissolved 0.291 0.291 4.1 0.0709 0.0709
Page 17 of 26

Table 5-56. Summary of Species-Specific Risk Conclusions for Listed Aquatic and 

Aquatic-dependent Species in RAAs

Pollutant

ECW

(Pre-Permit

Condition)

(μg/L)

ECW

(Post-Permit

Condition)

(μg/L)

CCC/2.0b

(μg/L)

RQ

(PrePermit)

RQ

(PostPermit)

Selenium, Total **  ** 36  

Zinc, Dissolved 0.493 0.452 40 0.0123 0.0113

Total Ammonia Nitrogen 0.00954a0.00742a- - -

** Note that Selenium values have been removed and are discussed later in this memo.
Page 18 of 26

The following table replaces Table 5-57 on page 5-144 of the BE:

Table 5-57. Sum of RQs for Metals Under Pre- and Post-Permit Conditions 

Taxa Cd RQ CrVI RQ Cu RQ Pb RQ Ni RQ Zn RQ Sum

RQ

Pre-PermitConditions

Freshwater Fish 0.0000077 0.00000133 0.035 0.000000985 0.000156 0.000134 0.0353

Freshwater Invertebrate 0.0000682 0.0000259 0.0422 0.0000152 0.00349 0.000395 0.0462

Freshwater plant 0.0000129 0.00000131 0.00144 0.0000000115 0.0000725 0.000000981 0.00153

Estuarine/Marine Fish 0.000106 0.00000208 0.0144 0.000258 0.0000688 0.00817 0.0231

Estuarine/

Marine Invertebrate 0.000122 0.000109 0.378 0.000124 0.0133 0.00313 0.395

Saltwater plant 0.0000932 0.0000000193 0.06 0.000364 0.0355 0.0000522 0.0959

Post-Permit Conditions

Freshwater Fish 0.00000705 0.00000112 0.028 0.000000937 0.000156 0.000132 0.0283

Freshwater Invertebrate 0.0000624 0.000022 0.0337 0.0000145 0.00349 0.000387 0.0377

Freshwater plant 0.0000118 0.00000111 0.00115 0.000000011 0.0000725 0.000000961 0.00124

Estuarine/Marine Fish 0.0000851 0.00000201 0.0113 0.000229 0.0000688 0.00749 0.0191

Estuarine/

Marine Invertebrate 0.0000981 0.000106 0.295 0.00011 0.0133 0.00287 0.311

Saltwater plant 0.0000749 0.0000000187 0.0468 0.000323 0.0354 0.0000478 0.0827
Page 19 of 26

II. Selenium

After further examination and analysis, we believe that our original estimates of selenium 

loadings originating from exhaust gas scrubber effluent are elevated by at least one to three 

orders of magnitude. First, as part of EPA’s original estimates, we grossly overestimated the 

numbers of vessels expected to discharge exhaust gas scrubber water into waters subject to the 

permit. Secondly, we believe matrix interference elevated measured selenium concentrations in 

both the influent and effluent results on which we based our estimates for modeled loadings. 

Additionally, , when vessels are stationary, their discharge rates will be reduced because the 

engines will only be on partial power (EPA estimated volume discharged based on maximum 

power output and did not quantify the effect of engines running on partial power). When these 

numerous conservative assumptions are taken into account, the total loading and concentrations 

of this discharge decreases tremendously. 

a. Overestimating Vessels Utilizing this Technology During the Permit Term

In the Biological Evaluation, we estimated that at any given time, 10% of certain vessels (oil and 

gas tankers, cruise ships, or cargo/bulk carriers) would be discharging exhaust gas scrubber 

effluent. Those vessel numbers were combined with an estimated discharge volume and 

concentration to generate loadings. As you know, we translated the numbers of vessels in a 

water body into “vessel equivalents.” For example, the port of Houston is estimated to have 

18.29 oil and gas tanker equivalents2(i.e., on average 18.29 oil and gas tankers would be 

operating in Houston at any given time). Using the 10% scenario, we estimated that 1.829 oil

and gas tanker vessel equivalents would be discharging exhaust gas scrubber effluent (i.e., on 

average 1.829 oil and gas tankers would be discharging that effluent at any given time).

We communicated with the Exhaust Gas Cleaning Systems Association to obtain a more

accurate number of vessels actually utilizing these systems. In an October 22, 2012 

correspondence with us, the director of that association, Don Gregory, sent information on all 

commercial installations and orders to date. Mr. Gregory noted that the information “is the 

definitive list from members”. Of systems currently installed, in design, or on order, there are 

nine vessels that installed open loop systems or for which there are designs or plans to install 

those systems on those vessels. Of those nine systems, two systems are no longer operational 

(on vessels AA and BB). Of the remaining seven, three to four are currently installed, and three 

are planned for next year. Hybrid systems are currently installed on four vessels, with plans to

install two more in the next year. See Table 5 below.

 

2

Populations presented are expressed as vessel equivalents where a vessel equivalent represents a single vessel 

discharging 24-hours per day in the harbor. For example, 1 vessel equivalent could represent 24 vessels that each 

operate (and discharge) for 1 hour in the harbor environment each day.
Page 20 of 26

Table 5. Commercial Installations and Orders of Open Loop Exhaust Gas Scrubbers to 

Date

Owner Vessel 

Name

Vessel 

Type

System 

type

Total 

Power

Install 

Date 

Notes

System A AA Ferry Open 0.8MW Fall 

2005

Test installation only

System B BB Cruise Open 8MW Oct 

2007

One of 5 main engines scrubbed

System C CC Container Open 8MW Sep 

2011

3 x 2.9MW aux engines scrubbed in one 

multi-inlet scrubber

System D DD RORO Open 9MW Dec 

2011

One scrubber each for 4 auxy engines (2MW 

each) and one scrubber for boiler (2.5t/hr 

steam)

System D EE RORO Open 9MW April 

2012

One scrubber each for 4 auxy engines (2MW 

each) and one scrubber for boiler (2.5t/hr 

steam)

System D FF RORO Open 9MW Fall 

2012

One scrubber each for 4 auxy engines (2MW 

each) and one scrubber for boiler (2.5t/hr 

steam)

System D GG RORO Open 9MW Spring 

2013

One scrubber each for 4 auxy engines (2MW 

each) and one scrubber for boiler (2.5t/hr 

steam)

System E HH VLGC Open 19MW 2013 Complete ship EGCS installation. Main 

engine (15MW) one scrubber, 3 auxys one 

multi-inlet scrubber (4MW)

System E II VLGC Open 19MW 2013 Complete ship EGCS installation. Main 

engine (15MW) one scrubber, 3 auxys one 

multi-inlet scrubber (4MW)

System F JJ RORO Hybrid 28MW Mar 

2013

Triple inlet 25MW scrubber for main & auxy 

engines and one single inlet 6MW for auxy 

in port

System G KK Container Hybrid 3MW Presently undergoing design

System H LL Test Lab Hybrid 600kW 2011 Single stream laboratory test installation

System I MM Bulk Hybrid 10MW 2009 Multistream test installation ME, 4 x AE, 

Boiler

System I NN Bulk Hybrid 10MW June 

2012

Multistream installation, ME, 3 x AE, Boiler

System J OO ROPAX Hybrid 21MW Sep 

2010

Main engine only

As part of our economic analysis, we expected new air rules coming into effect to drive higher 

levels of adoption of these systems (see EPA’s proposed VGP Fact Sheet for further discussion). 

Our initial estimates of vessels adopting these technologies were made nearly two years ago. 

However, we note that vessels could also utilize low sulfur fuel, liquid natural gas, or other 

strategies to meet the new rules. Based on how many of these systems have been ordered, 

designed, and installed, we believe these values to be gross overestimates. For instance, with 

only 7 or so functional open loop systems expected to be installed by permit operation date, it is 

unlikely that 1.829 oil tanker vessel equivalents will be using the technologies in Houston in any 

given day. The following table shows how many vessel equivalents discharging exhaust gas 

scrubber washwater would be expected if 1% of vessels utilized this technology in a given year, 

or if 0.1% of systems utilized this technology in a given year.
Page 21 of 26

Table 6. Adjusted Vessel Equivalents for 10%, 1%, and 0.1% with EGS Discharges 

Assumed to be Present in Each Harbor

Vessel Seattle Houston Miami New York

San 

Francisco

St 

Louis Duluth

10%

Oil/Gas Tankers 0.01 1.83 0.00 0.54 0.29 0.00 0.00

Large Cruise Ship 0.40 0.10 0.70 0.50 0.30 0.00 0.00

Cargo/Bulk Carrier 0.29 1.00 0.91 1.71 1.23 0.00 0.21

Total Vessel 

Equivalents 0.70 2.93 1.61 2.75 1.82 0.00 0.21

1%

Oil/Gas Tankers 0.00 0.18 0.00 0.05 0.03 0.00 0.00

Large Cruise Ship 0.04 0.01 0.07 0.05 0.03 0.00 0.00

Cargo/Bulk Carrier 0.03 0.10 0.09 0.17 0.12 0.00 0.02

Total Vessel 

Equivalents 0.07 0.29 0.16 0.28 0.18 0.00 0.02

0.1%

Oil/Gas Tankers 0.00 0.018 0.00 0.005 0.0032 0.00 0.00

Large Cruise Ship 0.004 0.001 0.007 0.005 0.003 0.00 0.00

Cargo/Bulk Carrier 0.003 0.01 0.009 0.017 0.012 0.00 0.002

Total Vessel 

Equivalents 0.007 0.029 0.016 0.028 0.018 0.00 0.002

b. Matrix Interference Resulting in Unreasonably High Measured Values

In our Exhaust Gas Scrubber Technical Analysis3, we noted that matrix interference could result 

in elevated selenium values. In that document, we stated: “In EPA’s 2009 Study of Discharges 

Incidental to Normal Operation of Commercial Fishing Vessels and Other Non-Recreational 

Vessels Less Than 79 Feet (USEPA, 2010), the high concentrations of chloride and other cations 

in seawater were found to interfere with the analytical determination of arsenic, as well as 

selenium. It is possible that a similar problem occurred in this study, and would explain the 

unexpectedly high concentrations of these metals in these samples of seawater and washwater.”

However, in developing our concentrations used in our model, we did not further account for this 

possibility of matrix interference. After further analysis, we believe this to be inappropriate. 

In our Exhaust Gas Scrubber Technical Analysis, we reviewed monitoring data from the effluent 

of three exhaust gas scrubber systems. Selenium was monitored in only one of the three reports 

we reviewed. We have the results from those studies, but do not have the raw laboratory data, 

including QA/QC information. The sampling method used was EPA 200.8, the same method for 

which we had the problems with identified matrix interference for arsenic and selenium in our 

 

3 USEPA. 2011b. Exhaust Gas Scrubber Washwater Effluent. EPA 800-R-11-006, November

2011.
Page 22 of 26

2010 study.

4 High Salinity waters have been documented to interfere with selenium analyses5

. 

As an example, bromines are compounds found in high quantities in seawater which can cause

notable selenium interference. Based on discussion with our EPA laboratory experts “Bromine 

may interfere with the determination of arsenic, selenium, and other analytes by ICP-MS [EPA 

method 200.8].... Environmental samples from coastal areas may contain bromine because sea 

water contains 65 mg/l bromine and a Canadian reference sediment, PACS-1, “has been found 

...to contain bromine at 663 mg/kg.””

6

 Furthermore “Selenium concentrations provided to the 

US EPA from ICP-MS measurements for bromine-industry wastes were found to have a high 

bias. Additional examination of this ICP-MS data has revealed that this selenium interference 

can be attributed to 81BrH+ ions and that the arsenic concentrations reported for these wastes are 

elevated by an indirect additive interference...i.e., the interference corrected arsenic signal.”6

As mentioned above, bromines are found in high concentrations in seawater, with an average 

bromide concentration in typical seawater (35 ppt) around 65 ppm. Notable interference can be 

observed as low as 100 or 200 ppb (personal communication, Terri White and Robin Costas, 

U.S. EPA Laboratory Scientists with substantial expertise in ICP-MS (EPA Method 200.8)). For 

instance, Terri White analyzed samples from an industrial operator which were taken from the 

thermal bromination process in the plant and had concentrations of 320 ppm Br. In that project, 

the measured 82Se concentration without correction was 855 μg/l; with correction it was 10.3

μg/l. Terri also spiked a blank sample with 10 μg/l in a controlled solution containing 100 ppm 

Br. In this test run, 82Se concentration without correction was 265 μg/l; with correction it was 12 

μg/l. In short, bromides have a notable impact of selenium results when they are not corrected. 

Additionally, it is notable that bromines are not the only compounds that might create significant

matrix interference in seawater.

All four areas where tests were conducted were from waters that have salinity, ranging from 

lightly brackish (Skagway at around 5 ppm7) to waters with higher salinities (Vancouver at 12-29 

ppt8, Juneau at 20-32 ppt9, and San Diego at 32-24 ppt10. Furthermore, 8 of 14 samples taken 

had raw intake water (exhaust gas scrubber influent) concentrations higher than the discharged

effluent concentration, which indicates that the exhaust gas scrubbing process is generally not a 

significant source of loading. See Figure 1 below. 

 

4 We also note that the arsenic loadings for our BE are also likely high due to matrix interference, but are not 

conducting further analysis because, despite likely interference, the estimated arsenic loadings are not likely to 

adversely affect listed species.

5 Moellmer, William O., Teron G. Miller, Steve Wilbur, and Emmett Soffey. 2007. ICP-MS Analysis of Trace 

Selenium in the Great Salt Lake. Spectroscopy. 

6 Hinners, Thomas A.,and Heithmar, Edward M., Interferences in ICP-MS by Bromine Species USEPA, Las Vegas, 

NV.

7

Source: http://water.epa.gov/polwaste/vwd/plume_dilution.cfm - Appendix B

http://water.epa.gov/polwaste/vwd/upload/2009_03_18_oceans_cruise_ships_compiled_ser_appendices.p

df

8

Source: http://www.pices.int/publications/scientific_reports/Report16/Section2.pdf

9

Source: http://www.afsc.noaa.gov/Publications/ProcRpt/PR1993-10.pdf

10 Source: http://www.portofsandiego.org/convention-center-expansion-project/san-diego-conventioncenter-expansion-documents/doc_view/1224-characterizing-the-spatial-and-temporal-variation-inturbidity.html
Page 23 of 26

In summary, we strongly suspect that the high selenium concentrations used in the original BE 

loading estimates are a direct result of matrix interference, and therefore were used

inappropriately, resulting in an overestimate of potential loadings from this discharge into US 

waters.

Figure 1. Selenium Concentrations in treated exhaust gas scrubber effluent from one 

treatment system 

From Figure 11 in HA & H-K. 2010. Holland America Line Sea Water Scrubber Technology 

Demonstration Project. Final Report by Holland America and Hamworthy-Krystallon to U.S. 

Environmental Protection Agency. March 31, 2010. (http://www.hollandamerica.com/assets//about-bestcruise-lines/Final_report.pdf).

c. Updated Selenium Loadings

With the information at hand, there is not a good way to correct for matrix interference based on 

results values alone. However, to provide a revised quantified loading estimate, we recalculated

loadings using the following two approaches. In the first model run, we used the average 

difference between the effluent and the intake selenium concentrations with an assumption that 

1% of certain vessels would discharge exhaust gas scrubber effluent. This resulted in an 
Page 24 of 26

estimated additional selenium discharge concentration of 14.5 μg/L input into our model 

(Scenario A). In the second scenario, we also estimated the average difference between the 

effluent and intake selenium concentrations; however, we replaced any differences that were 

negative with zeros (a conservative assumption that the treatment would not remove selenium)

with an assumption that 1% of certain vessels would discharge exhaust gas scrubber effluent. 

This resulted in a total selenium concentration of 31.2 μg/L input into our model (Scenario B). 

See Table 7 below which lists loading estimates for our seven areas (our reference action areas in 

the BE).

Table 7. Estimated Selenium Loading with a Post Hoc Correction to Compensate for likely 

Matrix Interference

Load 

Scenario

Permit 

Condition Analyte

Estuary Harbor Loads (lb/day)

River Harbor 

Loads (lb/day)

Seattle Houston

New 

York

San 

Fran Miami Duluth

St. 

Louis

Scenario A

PrePermit Se, Dissolved 0.202 0.385 0.342 0.233 0.174 0.0279 0

Scenario A

PostPermit Se, Dissolved 0.167 0.385 0.341 0.231 0.174 0.0278 0

Scenario A

PrePermit Se, Total 0.144 0.797 0.7 0.468 0.36 0.0575 0

Scenario A

PostPermit Se, Total 0.144 0.797 0.7 0.468 0.36 0.0575 0

Scenario B

PrePermit Se, Dissolved 0.411 1.54 1.36 0.913 0.698 0.111 0

Scenario B

PostPermit Se, Dissolved 0.376 1.54 1.36 0.911 0.698 0.111 0

Scenario B

PrePermit Se, Total 0.309 1.71 1.51 1.01 0.775 0.124 0

Scenario B

PostPermit Se, Total 0.309 1.71 1.51 1.01 0.775 0.124 0

As previously discussed in this memo, there are currently only a handful of vessels using exhaust 

gas scrubber systems which result in a discharge. Hence, in the early part of this permit term, 

and perhaps toward the end of the permit term, even 1% of certain vessels using these systems is 

an overestimate. If we assume that only 0.1% of certain vessels would be using these systems at 

a given time would result in even lower loadings to these estuaries11. Since the majority of 

estimated selenium loading estimated in our BE originates from exhaust gas scrubber systems, an 

order of magnitude reduction in the numbers of vessels discharging (from 1% to 0.1%) would 

result in nearly an order of magnitude reduction in the loading of selenium. In the interest of 

brevity, those results are not listed here, but by way of example, post permit total selenium 

loading into San Francisco would be reduced to 0.04-0.06 pounds per day in Scenario A, and 

0.10-0.12 pounds per day in Scenario B. 

 

11 0.1% estimate of certain vessels discharging exhaust gas system effluent is reasonable since there are currently 

only a handful of vessels for which these systems have been installed or ordered.
Page 25 of 26

Use of the loadings assuming that 1% of the certain vessels using exhaust gas scrubber systems 

discharging effluent would result in an average concentration of disolved selenium in our 

estuarine modeled harbors of 0.0064 μug/L for scenario A, and 0.024 μg/L for scenario B in post 

permit settings. Of the 14 modeled estuaries, hypothetical harbor scenario 2 would have the 

maximum concentration of 0.0167 μg/L dissolved selenium for scenario A in pre-permit setting, 

and 0.0671 μg/L dissolved selenium in scenario B in a post permit setting. The average post 

permit concentrations of total selenium would be 0.012 μg/L in Scenario A and 0.026 μg/L in 

scenario B, with the maximum concentrations found in hypothetical harbor scenario 2 being 

0.0346 μg/L in Scenario A and 0.0745 μg/L in Scenario B. In short, these concentrations are

trace amounts.

d. Updated Selenium Risk Quotients

The previous BE estimates for risk quotients for selenium, using the high selenium loadings, 

resulted in risk quotients that were all very low (the maximum values being 0.136 for estuarine 

vertebrates and 0.108 for saltwater mammals). However, when one considers the reduction in 

vessels discharging this effluent, combined with a reduction in loading per vessel, the maximum 

risk quotient values become exceptionally small. Hence, we believe the loadings from selenium 

resulting from exhaust gas scrubber discharges would be insignificant and discountable. See 

Tables 8, 9, and 10 below.

Table 8. ECw RQ Comparison for Selenium

Taxa Analyte

Previous BE Estimate Scenario A Scenario B

RQ

(PrePermit) 

RQ

(PostPermit)

RQ

(PrePermit) 

RQ

(PostPermit)

RQ

(PrePermit) 

RQ

(PostPermit)

Freshwater Fish Se, Total 0.0023 0.0023 <0.0001 <0.0001 <0.0001 <0.0001

Freshwater Invertebrate Se, Total 0.00221 0.00221 <0.0001 <0.0001 <0.0001 <0.0001

Freshwater plant (Vascular) Se, Total <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001

Estuarine/Marine Fish Se, Total 0.00354 0.00354 <0.0001 <0.0001 0.00011 0.00011

Estuarine/Marine 

Invertebrate Se, Total 0.0113 0.0113 0.000164 0.000164 0.000352 0.000352

Saltwater plant (Vascular) Se, Total 0.0337 0.0337 0.000488 0.000488 0.00105 0.00105

Table 9. ECt RQ Comparison for Selenium

Taxa Analyte

Previous BE Estimate Scenario A Scenario B

RQ

(PrePermit) 

RQ

(PostPermit)

RQ

(PrePermit) 

RQ

(PostPermit)

RQ

(PrePermit) 

RQ

(PostPermit)

River Vert Se, Total 0.0105 0.0105 0.000152 0.000152 0.000327 0.000327

River Invert Se, Total 0.028 0.028 0.000406 0.000406 0.000875 0.000875

Estuary Vert Se, Total 0.136 0.136 0.00198 0.00198 0.00426 0.00426

Estuary Invert Se, Total <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
Page 26 of 26

Table 10. Eco RQ Comparison for Selenium

Taxa Analyte

EGS Baseline Scenario A Scenario B

RQ

(PrePermit) 

RQ

(PostPermit)

RQ

(PrePermit) 

RQ

(PostPermit)

RQ

(PrePermit) 

RQ

(PostPermit)

Mammals (Freshwater) Se, Total 0.0203 0.0203 0.000294 0.000294 0.000633 0.000633

Birds (Freshwater) Se, Total 0.0101 0.0101 0.000147 0.000147 0.000316 0.000316

Mammals (Saltwater) Se, Total 0.108 0.108 0.00157 0.00157 0.00337 0.00337

Birds (Saltwater) Se, Total 0.054 0.054 0.000783 0.000783 0.00168 0.00168

III. Conclusions

Based on the supplementary analyses above, we identified additional copper loadings from antifoulant paints, and how they would affect copper concentrations in our 14 modeled harbors. We 

also briefly discussed how it would impact our risk quotients for copper, and our interpretations. 

In this memo, we did not discuss the trade off that comes with using anti-foulant paints with the 

benefits of reducing attached living organisms to vessels hulls (thereby significantly reducing 

risk of introducing or dispersing invasive species). However, we note that we have discussed 

this topic at length during our consultation, and we appreciate your consideration of that issue. 

Please see the VGP fact sheet, the BE, and our technical development document on hull 

husbandry for additional written discussion. Additionally, based on the appropriate revisions to 

our analyses of exhaust gas scrubbers, we believe selenium loadings from exhaust gas scrubber 

effluent are negligible.

We believe the information discussed above supports the conclusion that either copper or 

selenium loadings from VGP and sVGP discharges are not likely to adversely affect listed 

species or critical habitat. We would be pleased to discuss these analyses and our results with 

you in greater detail to support your analyses as you deem appropriate before delivery of your 

draft Biological Opinion. Once again, thank you for your continued help and advice in this 

consultation process and we look forward to its successful conclusion.