EPA's Vessel General Permit and Small Vessel General

These regulations established a standard for the allowable concentration of living organisms
contained in ships’ ballast water discharges.
Similarly, to reduce the number of ANS in ballast water, EPA has included several requirements
in the VGP. The following requirements are likely to reduce the exposure of listed species to
ANS:
� Minimize or avoid ballast water discharge and update in critical habitat
� Ballast water numeric discharge limits (consistent with the Coast Guard’s 2012
standards):
o < 10 living organisms/m 3 ballast water, for organisms greater than or equal to 50
micrometers
o < 10 living organisms/mL ballast water, for organisms less than 50 micrometers and
greater than or equal to 10 micrometers
� Vessels may meet the above standards by one of the following management methods
o Onshore treatment of ballast water
o Use of public water supply for ballast water
o No discharge of ballast water
o Ballast water treatment system (with additional testing, calibration, and reporting
requirements)
In the BE, EPA concluded that their VGP numeric effluent limits are likely to result in a “very
small absolute risk of invasion.” However, as described the BE, an estimated 196 million m 3 of
ballast water is released into U.S. waters annually. Therefore, EPA requirements authorize an
annual discharge of:
� < 1.96 billion living organisms, greater than or equal to 50 micrometers
� < 1.96 trillion living organisms, less than 50 micrometers and greater than or equal to 10
micrometers
For the above calculation, we assumed that all released ballast water in waters of the U.S. would
be subjected to the numeric discharge limits of the VGP; however, this not the case. The
majority of vessels in the U.S. (115,000 to 138,000 vessels) would be covered under the sVGP,
which does not limit the number of living organisms that may be released into waters of the U.S.
Above, we calculated the annual number of living organisms that EPA authorized to be released
in ballast water using the VGP numeric effluent limits; however, EPA does not require numeric
effluent limits for ballast water under the sVGP. Because the majority of vessels are covered
under the sVGP and would not be required to meet numeric treatment limits, the total number of
living organisms in ballast water that EPA authorizes to be released into waters of the U.S. is
likely:
� > 1.96 billion living organisms, greater than or equal to 50 micrometers
� > 1.96 trillion living organisms, less than 50 micrometers and greater than or equal to
10 micrometers
While we are unable to quantitatively estimate how many of these organisms are likely to
become established in waters of the U.S. (NAS 2011), we used the NEMESIS database to
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