Problem Statement: Exotic Species Introductions: “Environmental Pathogens”
The 303(d) listing of exotic species is based on documented examples of aquatic biological invasions, both worldwide and local, which have caused demonstrable injury to ecological integrity, economic activity, and public health15. As such, random exotic species introductions to an estuarine ecosystem are analogous to the exposure of a person to random bacterial or viral pathogens, for instance in drinking water. To prevent water-borne disease, our society desires a national target of “zero” pathogens for our tap water, but the standards we set are based on the limits of our best available treatment technology. Since we have a hypothetical goal of completely eliminating exotic species introductions, the system that we develop to protect waters of the state from these “environmental pathogens” could parallel our nation’s technology-based approach to protecting drinking water supplies from water-borne disease, discussed below.
Exotic Species Threaten the Regional Ecology, Economy, and Public Health
A growing body of scientific evidence strongly suggests that shipping ballast water and perhaps hull fouling are the most significant sources of exotic species to the San Francisco Estuary, which can adversely affect the region’s ecology, economy, and public health. Many exotic species now dominate several habitats in the estuary, reducing biodiversity and in some cases displacing native species, and the rate of invasion within the estuary has been increasing in the last ten years. A report published in January 1999 by Cornell University estimated that exotic species cost the United States $122 billion per year16. Threats to economic activities include the fouling of water supply systems, the destruction of fisheries, and the compromising of levee structural integrity. Public health is threatened by the potential for introduction of toxic dinoflagellate algae (e.g., red tide), cholera and other pathogenic organisms, and the discharge of sewage-contaminated ballast water. Scientific evidence suggests that the risks posed to beneficial uses by current and future introductions of exotic species are as great as any other pollutant regulated under the Clean Water Act.
As the most significant pathway of exotic species introductions, ballast water and hull fouling discharges threaten most of the beneficial uses of the San Francisco Estuary and its tributaries. The broad threat relates to the wide range of organisms that have been documented to survive transoceanic transport in ballast tanks and on ship hulls. Ballast water studies from Coos Bay, Oregon and Chesapeake Bay have revealed species ranging from viruses and dinoflagellate cysts to schools of juvenile fish17. The potential effects of a new exotic species in the estuary are as broad as the diversity of species found in ballast water. Based on observed invasions, a new exotic species could displace native and/or sensitive species, deplete or pollute aquaculture, foul water delivery systems, decimate fisheries and associated economies, lead to invasion of freshwater habitats, threaten the health of swimmers, and so on. Often the establishment of an exotic species is unimpeded by lack of native predators or competitors. The threatened beneficial uses include cold freshwater habitat (COLD), ocean, commercial, and sport fishing (COMM), estuarine habitat (EST), fish migration (MIGR), fish spawning (SPAWN), municipal and domestic supply (MUN), preservation of rare and endangered species (RARE), water contact recreation (REC1), noncontact water recreation (REC2), shellfish harvesting (SHELL), warm freshwater habitat (WARM), and wildlife habitat (WILD).
Treatment-Based Standards: Drinking Water Approach to Pathogen Control
In terms of numeric targets, exotic species in estuary water is more akin to pathogens in drinking water than toxic pollutants in estuary water. For example, our society desires a standard of “zero” for pathogens in tap water, but our system of measuring compliance considers the performance of the best available treatment technology. Since instances of water-borne disease are now very rare, there is general acceptance of our national treatment-based standards for drinking water, without employing expensive research-level analyses to continually check for the presence of viruses and other microorganisms. The national treatment standard for viruses in drinking water, established in place of maximum contaminant levels or MCLs, is “4-log-kill” or 99.99% removal of viruses. For the protozoan cyst Giardia, the treatment standard for drinking water is 3-log kill or 99.9% removal18. In some cases a single non-native organism has the potential to initiate a biological invasion of the estuary, and for this reason, a numeric target of multiple-log kill, based on treatment or best management practices, may be the desired standard for exotic species.
The design of ballasting equipment allows for incomplete exchange of ballast water and sediments with ocean water. Ballast sediments are probably largely retained in these operations, and the sediments are known to contain a wide range of viable organisms, depending on the length of the ship’s journey. Therefore, although limited information is available, the order of magnitude for exotic species removal afforded by open ocean exchange is probably around 90%, or “1-log-kill.” Such a level of treatment would be inadequate for protection of a drinking water source from pathogens. Additionally, the most stringent of the mandatory open ocean exchange requirements in place today allows exemptions for heavy weather conditions, when ballast water exchanging operations can jeopardize the ship and its crew. In such situations, the ballast water discharged is completely unabated, or 0-log-kill.
While crew safety is of paramount importance, the exemptions under existing mandatory guidelines in the Great Lakes, etc., would continue to allow an unabated threat to this estuary’s beneficial uses. This ongoing threat suggests the need for a comprehensive technology evaluation of the collection and treatment of ballast water at ports, also known as “on-shore treatment.” On-board treatment should also be considered, but for numerous legal and technical reasons, it may not be feasible to implement. For example, U.S. authority to require such permanent elements on ships under foreign flags (i.e., 97% of the world fleet) is severely limited.
Numerous laws prevent the intentional introduction of non-native species in both aquatic and terrestrial habitats, but laws and regulations currently in effect do not explicitly require characterization, abatement or treatment of ship ballast water and hull fouling. Provisions of the federal Clean Water Act (CWA) and the state Porter-Cologne Water Quality Control Act (California Water Code or CWC) could apply to the introduction of exotic species from ship hulls or in ballast water releases, as a waste discharge of a biological pollutant. Ballast water and hull fouling constitute a “waste” as defined by the CWC at Section 13050.
A potential conflict exists between the CWA statute and its implementing regulations at 40 CFR 122.3(a) that does not require vessels to have permits for discharges under the National Pollutant Discharge Elimination System (NPDES) of point source pollution permitting. As described above, the federal and state statutes define these discharges as point sources of pollution, but the regulations authored by the EPA presently may not allow the regulating system to impose any accountability or control on them. On January 13, 1999, a coalition of scientists and diverse groups formally petitioned the EPA Administrator to repeal the regulations set forth at 40 CFR 122.3(a), on the grounds that any vessel exclusion is illegal and runs counter to case law. Eighteen representatives to Congress from the Bay Area jointly signed a bipartisan letter dated February 11, 1999, urging the Administrator to repeal the vessel discharge regulation at 40 CFR 122.3(a), on the basis that the regulation was drafted at a time when this exotic species vector was poorly understood. EPA responded on April 6, 1999, committing to a staff report on regulatory options by September 1999.
The permitting system under the California Water Code, “waste discharge requirements” or WDRs, could be used to regulate vessel discharges to waters of the state. However, it is desirable to implement such surface water discharges under the federal NPDES program for two reasons. First, all surface water discharges in California are presently regulated under the NPDES program, and any permitting program for ballast water should be consistent with this approach. Second, states’ authority to regulate interstate and international commerce is legally questionable. For this reason, use of the federal permitting system may be more legally defensible.