EXERPT:
Blackwater is sewage, wastewater
from toilets and medical facilities, which can contain harmful
bacteria, pathogens, diseases, viruses, intestinal parasites,
and harmful nutrients. Discharges of untreated or inadequately
treated sewage can cause bacterial and viral contamination of
fisheries and shellfish beds, producing risks to public health.
Nutrients in sewage, such as nitrogen and phosphorous, promote
excessive algal growth, which consumes oxygen in the water and
can lead to fish kills and destruction of other aquatic life.
A large cruise ship (3,000 passengers and crew) generates an
estimated 15,000 to 30,000 gallons per day of blackwater waste.
Graywater is wastewater from
the sinks, showers, galleys, laundry, and cleaning activities
aboard a ship. It can contain a variety of pollutant substances,
including fecal coliform bacteria, detergents, oil and grease,
metals, organics, petroleum hydrocarbons, nutrients, food waste,
and medical and dental waste. Graywater has potential to cause
adverse environmental effects because of concentrations of nutrients
and other oxygen-demanding materials, in particular.
Graywater is typically the
largest source of liquid waste generated by cruise ships (90%-95%
of the total). Estimates of graywater range from 30 to 85 gallons
per day per person, or 90,000 to 255,000 gallons per day for
a 3,000-person cruise ship.
Cruise ships produce hazardous
wastes from a number of on-board activities and processes, including
photo processing, dry-cleaning, and equipment cleaning.
These materials contain a wide
range of substances such as hydrocarbons, chlorinated hydrocarbons,
heavy metals, paint waste, solvents, fluorescent and mercury
vapor light bulbs, various types of batteries, and unused or
outdated pharmaceuticals. Although the quantities of hazardous
waste generated on cruise ships are small, their toxicity to
sensitive marine organisms can be significant. Without careful
management, these wastes can find their way into graywater, bilge
water, or the solid waste stream. Solid waste generated on a
ship includes glass, paper, cardboard, aluminum and steel cans,
and plastics. Much of this solid waste is incinerated on board,
and the ash typically is discharged at sea, although some is
landed ashore for disposal or recycling.
Marine mammals, fish, sea turtles,
and birds can be injured or killed from entanglement with plastics
and other solid waste that may be released or disposed off of
cruise ships. On average, each cruise ship passenger generates
at least two pounds of non-hazardous solid waste per day and
disposes of two bottles and two cans.
With large cruise ships carrying
several thousand passengers, the amount of waste generated in
a day can be massive. For a large cruise ship, about 8 tons of
solid waste are generated during a one-week cruise.12 It has
been estimated that 24% of the solid waste generated by vessels
worldwide (by weight) comes from cruise ships. Most cruise ship
garbage is treated on board (incinerated,pulped, or ground) for
discharge overboard. When garbage must be off-loaded (for example,
because glass and aluminum cannot be incinerated), cruise ships
can put a strain on port reception facilities, which are rarely
adequate to the task of serving a large passenger vessel (especially
at non-North American ports). On a ship, oil often leaks from
engine and machinery spaces or from engine maintenance activities
and mixes with water in the bilge, the lowest part of the hull
of the ship. Oil, gasoline, and byproducts from the biological
breakdown of petroleum products can harm fish and wildlife and
pose threats to human health if ingested. Oil in even minute
concentrations can kill fish or have various sub-lethal chronic
effects.
Bilge water also may contain
solid wastes and pollutants containing high amounts of oxygen-demanding
material, oil and other chemicals. A typical large cruise ship
will generate an average of 8 metric tons of oily bilge water
for each 24 hours of operation.15 To maintain ship stability
and eliminate potentially hazardous conditions from oil vapors
in these areas, the bilge spaces need to be flushed and periodically
pumped dry. However, before a bilge can be cleared out and the
water discharged, the oil that has been accumulated needs to
be extracted from the bilge water, after which the extracted
oil can be reused, incinerated, and/or offloaded in port. If
a separator, which is normally used to extract the oil, is faulty
or is deliberately bypassed, untreated oily bilge water could
be discharged directly into the ocean, where it can damage marine
life. A number of cruise lines have been charged with environmental
violations related to this issue in recent years.
Cruise ships, large tankers,
and bulk cargo carriers use a tremendous amount of ballast water
to stabilize the vessel during transport. Ballast water is often
taken on in the coastal waters in one region after ships discharge
wastewater or unload cargo, and discharged at the next port
of call, wherever more cargo is loaded, which reduces the need
for compensating ballast. Ballast water discharge typically contains
a variety of biological materials, including plants, animals,
viruses, and bacteria. These materials often include non-native,
nuisance, exotic species that can cause extensive ecological
and economic damage to aquatic ecosystems. Ballast water discharges
are believed to be the leading source of invasive species in
U.S.marine waters, thus posing public health and environmental
risks, as well as significant economic cost to industries such
as water and power utilities, commercial and recreational fisheries,
agriculture, and tourism.16 Studies suggest that the economic
cost just from introduction of pest mollusks (zebra mussels,
the Asian clam, and others) to U.S. aquatic ecosystems is more
than $6 billion per year.17 These problems are not limited to
cruise ships, but there is little cruise-industry specific data
on the issue, and further study is needed to determine cruise
ships' role in the overall problem of introduction of non-native
species by vessels.
Air pollution from cruise ships
is generated by diesel engines that burn high sulfur content
fuel, producing sulfur dioxide, nitrogen oxide and particulate
matter, in addition to carbon monoxide, carbon dioxide, and hydrocarbons.
EPA recognizes that these emissions from marine diesel engines
contribute to ozone and carbon monoxide nonattainment, as well
as adverse health effects associated with ambient concentrations
of particulate matter and visibility, haze, acid deposition,
and eutrophication and nitrophication of water.18 EPA estimates
that large marine diesel engines accounted for about 1.6% of
mobile source nitrogen oxide emissions and 2.8% of mobile source
particulate emissions in the United States in 2000.
