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MARINE ENVIRONMENTS:
Marine environments are classified into three broad categories:
Estuaries:
semi-enclosed coastal water bodies that have a free connection to the
open ocean, where seawater enters and mixes with freshwater derived
from land drainage with high productivity.
Coastal waters: Overlie the inner continental shelf, typically within 4.8
km of shore. Oceanic processes affect coastal waters much more greatly
than estuaries, with various oceanic phenomena.
Open ocean: waters overlying the outer continental shelf, continental
slope and beyond constitute of the open ocean. Open ocean systems have
considerable capacity to dilute, transport, and disperse wastes and
associated pollutants due to their large volume and free exchange of
water and, hence, are less vulnerable to the impact of waste disposal than
other marine waters.
 Many organisms inhabiting the open sea spend part of their lives in
coastal waters and estuaries, where they are subjected to great
concentrations of contamination.
According to Group of Expert on the Scientific Aspect of Marine
pollution (GESAMP) marine pollution is defined as the “introduction by
man, directly or indirectly, of substances or energy into the marine
environment (including estuaries) resulting in such deleterious effects as
harm to living resources, hazards to human health, hindrance to marine
activities including fishing, impairment of quality for use of seawater and
reduction of amenities.”
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 Distinction is made between pollution and contamination in marine
environments. Pollution occurs when the concentration of a waste
substance exceeds the level at which damaging effects are manifested
in the sea.
In contrast, contamination takes place when the
concentration of a waste substance in seawater, sediments, or
organisms exceeds background levels without causing measurable
damaging effects.
 Pollutants enter estuarine and coastal marine waters by numerous
routes.
(1) Untreated or poorly treated sewage discharged.
(2) Release large numbers of pathogenic microorganisms that can
significantly degrade water quality and pose a serious health hazard
to man.
(3) Accumulating of toxic substance derived from industrial and
municipal wastes, dredged-spoils, and nonpoint source pollution.
(4) Physical, chemical, and biological processes affect the distribution
and fate of these substances in the marine environment.
(5) Various chemical processes – particularly adsorption, desorption,
dissolution, oxidation, reduction, flocculation, volatilization,
neutralization, and precipitation - influence the availability,
persistence, and degradation of wastes in sediments and overlying
waters.
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 The deterioration of estuarine and coastal marine waters by waste
inputs is often severe and accompanied by a number of over effect
such as:
1. Degraded water quality manifested by hypoxia or anoxia over
extensive area;
2. Disease, abnormalities, reproductive failure, and mortality of fish
and shellfish population;
3. Changes in abundance, diversity, and distribution of marine
communities;
4. Loss of submerged aquatic vegetation, wetlands, and other critical
habitats;
5. Closure of shellfish grounds and beaches due to chemical or
microbial contamination;
6. Outbreaks of human disease caused by individuals swimming in
contaminated marine waters or consuming contaminated shellfish.
 Deep-sea bed has been used for disposal of dredged spoils, sewage
sludge, industrial wastes, pharmaceuticals, and low level
radioactive wastes.
International treaties have been enacted to
control the disposal of such wastes. Two of the most important are
the Convention on the Prevention of Marine Pollution by Dumping
of Wastes and Other Matter of 1972 (better known as the London
Dumping Convention and now simply the London Convention.
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 The disposal of wastes into the deep sea effectively isolates
pollutants from surface living communities in the open ocean and
precludes their impact on coastal environments.
 Studies have revealed increased density of some benthic
populations at the dumpsite, owing to increased concentrations of
organic carbon which serves as an additional food source.
However, the species diversity of the benthic community has
declined in response to the sludge dumping.
 The NEADS dumpsite, which has been in existence since 1967. It
lies at a mean depth of 440 m. This dumpsite received large
quantities (-2000 mt/yr) of low level radioactive wastes from
nuclear power stations.
 There is little evidence of radioactive impacts on the benthic fauna
at NEADS.
 Although contents of radioactive waste dumped at NEADS are
expected to corrode and leach through their containment sometime
in the future, the delay should allow enough time to ensure the loss
of radioactivity via decay of shorter-lived radionuclide.
 Pollutants in marine environments derive from both point and
nonpoint sources (Table 3).

Primary point-source categories responsible for the introduction of
pollutants to U.S. marine waters. Major contaminant loadings of
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U.S. marine waters from point sources have decreased substantially
during the past two decades due to tighter state and federal
government regulations and improved industrial controls of pointsource discharges.
However, the input of non-point-source
pollutants is more problematical, and acute and insidious biological
effects of these pollutants are extremely difficult to assess.21
 Nonpoint runoff is a major source of pollutants to rivers.
Nonpoint-source pollutants also originate from this activities at sea
associated with accidental release.

It is quantitatively significant, particularly on developed
coastlines. Nonpoint pollution occurs in virtually all estuarine and
coastal marine waters along developed shorelines, varying
dramatically both spatially and temporally.
 Because nonpoint runoff is so diffuse, wide spread, and variable, it
is difficult to accurately quantify. Lack of information-gathering,
inadequate systematic analyses of gathered data, and ineffective
dissemination of results.
 Marine waste disposal activities continue to be overwhelmingly
concentrated in estuarine and coastal marine waters, which receive
80-90% of all wastes released to marine environments worldwide.
 Outfall
discharges
and
runoff
generally
deliver
greater
concentrations of pollutants to these coastal systems than dumping.
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 Because of the great variability in composition of marine-dumped
wastes and the intermittent and localized nature of dumping
operations, it is difficult to compare pollutant inputs derived from
sewage sludge and dredged material dumping and those resulting
from pipeline discharges and runoff. Some general observations
are possible (Table 4).

Nonpoint runoff is the major contributor of fecal coli form bacteria
to U.S. marine waters. It also represents the principal source of
suspended solids, total phosphorus, and certain heavy metals.
 The types of pollutants found either locally or regionally depends
on several important factors, theses factors are:
(1) The relative contributions of agricultural and urban runoff,
(2) The type and magnitude of industrial discharges,
(3) The size and number of sewage treatment plants that release effluent,
(4) The amount of harbor or port maintenance,
(5) Affects the input of pollutants and their subsequent biotic impacts on
both local and regional scales.
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