EPA's Vessel General Permit and Small Vessel General

metals in marine mammals is generally limited to tissue concentrations (Varanasi et al. 1994,
Sanpera et al. 1996, Wagemann et al. 1996, Wood and VanVleet 1996, Sydeman and Jarman
1998, Meador et al. 1999, Welfinger-Smith et al. 2011). There are a few in vitro investigations
demonstrating cytolotoxic, genotoxic and immunotoxic effects of metals in marine mammal
tissues (DeGuise et al. 1996, Kakuschke et al. 2008, Frouin et al. 2010, Chen et al. 2012). While
data from in vitro studies are difficult to interpret in ecological terms, they identify the
mechanisms by which pollutants affect organisms.
Because EPA’s modeled concentrations of the metals aluminum, arsenic, cadmium, chromium,
lead, nickel, and zinc are well below levels documented to cause adverse effects in aquatic and
aquatic-dependent species, we do not anticipate adverse effects to listed species from these
metals discharged from vessels, even given the uncertainties associated with the assessment. We
expect that monitoring of discharges from new builds will assist in the reduction of uncertainty
regarding these concentrations and assist in the verification of assumptions made herein.
Copper
Copper concentrations estimated by EPA from anti-fouling hull coatings and other discharges
range up to 2.99 ug/L pre-permit and 2.33 ug/L post-permit in hypothetical estuarine harbor
scenarios, and up to 0.164 ug/L pre-permit and 0.131 ug/L post-permit in hypothetical river
harbor scenarios, suggesting an approximately 20 percent reduction in discharges of dissolved
copper. Post permit copper estimates fell below the response thresholds selected by EPA for
evaluating risks of exposure to copper. These thresholds ranged from 3.5 to 119 ug/L for
freshwater organisms and from 7.9 ug/L to 249 ug/L for estuarine/marine organisms. The
threshold values EPA selected for freshwater and estuarine/marine invertebrates and for marine
vertebrates were derived from NOECs and LOECs. The invertebrates NOECs were 2.5 ug/L and
6.1 for freshwater and estuarine/marine organisms, respectively. The NOEC for
estuarine/marine vertebrates was 249 ug/L.
EPA predicts that high-end concentrations are likely to be overestimations of even worst-case
scenarios. However, we believe that given the uncertainties in EPA’s exposure analysis, species
may be exposed to copper concentrations from vessel discharges that not only meet but exceed
estimates calculated by EPA. In addition, vessel discharges are likely to combine with other
sources of copper in waterways to produce even higher concentrations than those predicted in
this analysis. At present, copper impairs 14,000 miles of rivers and streams (12% of impaired
rivers and streams) and 964 square miles of bays and estuaries (43% of impaired bays and
estuaries). Due to the high sensitivity of aquatic species to copper, adverse effects to listed
species are likely to occur if copper discharges from vessels reach concentrations predicted in
this analysis.
As described by EPA, copper is a nutritionally essential inorganic element for all species, both
plant and animal, and thus has the potential to accumulate in tissues of aquatic animals. As long
as water column or dietary concentrations are not so high as to overwhelm homeostatic
mechanisms, aquatic species are able to regulate their internal body burden of copper. Aquatic
organism exposure to copper concentrations in excess of nutritional needs via other potential
routes of exposure in addition to direct waterborne toxicity (e.g. dietary toxicity) may pose a
286