EPA's Vessel General Permit and Small Vessel General

Metals
sVOCs and VOCs
Pollutant
Biochemical Oxygen
Demand (BOD, mg/L)
Hexane Extractable Oil
and Grease (HEM, mg/L)
Silica Gel Treated-
Hexane Extractable Oil
and Grease (SGT-HEM,
mg/L)
Aluminum (total, μg/L)
Cadmium (dissolved,
μg/L)
Chromium (dissolved,
μg/L)
Copper (dissolved, μg/L)
Nickel (dissolved, μg/L)
Zinc (dissolved, μg/L)
2,4,6-Trichlorophenol
(μg/L)
Benzene (μg/L)
Bis (2-ethylhexyl)phthalate
(μg/L)
Trichloroethene (μg/L)
Point
Estimate Used
in BE
190
Detection
frequency
Mean (range)
50 th /75 th /90 th
Percentiles b
7/7 190 (2-770) 14/330/770
9.3 7/7 9.3 (1.1-44) 5.2/7/44
4.4
370
1.9
12
100
9.2
130
7
61
15
2.6
7/7 4.4 (1.1-18) 2.4/3.5/18
7/7 370 (26-940) 330/640/940
1/7 1.9 (nd-10) nc/nc/10
5/7 12 (nd-56) 1.6/17/56
7/7 100 (6.6-350) 56/120/350
6/7 9.2 (nd-15) 8.8/14/15
7/7 130 (53-250) 100/190/250
1/7 7 (nd-24) nc/nc/24
4/7 61 (nd-410) 0.1/1.3/410
4/7 15 (nd-71) 1.4/21/71
1/7 2.6 (nd-0.3) nc/nc/0.3
a
Nondetect (censored) concentrations were replaced with ½ of the reporting limit for calculating average
concentrations.
b
Percentiles are the concentrations of each analyte below which at least that percentage of the values fall.
So the 75th percentile is the concentration below which at least 75% of the observations were found.
c
Distribution statistics were only calculated when analytes were detected at a sufficient frequency.
Deck Washdown. Deck washdown occurs from all vessels as a result of deck cleaning.
Constituents in the discharge can include detergent, soap, deck surface components (e.g., rust,
paint chips) and anything dropped, spilled, dripped, or scattered onto the deck surface. Deck
washdown volumes vary widely and are highly dependent on a vessel’s purpose, service, and
practices. For example, since aesthetics are important to the industry, deck washdowns may be
performed more frequently on cruise ships than other types of vessels. EPA analyzed the risk of
this discharge in its BE due to the high number of vessels discharging, the large volume and
frequency of discharges, along with the potentially high risk posed by the concentration and
types of pollutant discharged.
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