Pollution has considerably degraded the coastal and marine environment,
including estuaries, of the region over the past 30 years. Increased wastes
from landbased urban, industrial and agricultural activities as well as
from offshore oil and gas exploitation are discharged untreated in the
coastal region (MoSTE Viet Nam 1999).
The most significant sources of pollution include oil from ships, sewage
and other domestic wastes, and industrial effluents. The main route of marine
transport of oil from the Gulf is across the Arabian Sea, and accidental
oil spills have been frequently reported along oil transport routes, at
points of discharge and loading of oil carriers. The shipping of oil coupled
with increasing emphasis on offshore oil exploration makes the northern
Indian Ocean extremely vulnerable to oil pollution. Oil spills also cause
severe pollution in ports in Bangladesh, Indonesia, Malaysia and Pakistan
(DoE Malaysia 1996, 1998). In addition, the cleaning of oil tanks in and
around ports has led to the frequent formation of tar-balls on the southwestern
beaches of Sri Lanka. In the PICs, marine pollution from ships is a threat
that is likely to increase as trade and economies develop further.
The enhanced use of agrochemicals on land and discharge of chemicals
into seawater is a common problem. An estimated 1 800 tonnes of pesticides
enter the Bay of Bengal every year (Holmgrem 1994). In the Sea of Japan,
a survey has revealed high concentrations of mercury, the source of which
could have been wastewater from chemical plants (MSA 1997), while the
Russian Federation admitted in 1993 that the former Soviet Union had dumped
nuclear wastes there 'for decades' (Hayes and Zarsky 1993). In spite of
international regulations, marine pollution in the Sea of Japan and the
Yellow Sea has continued to worsen.
Tourism and other recreational activities also pose a threat to coastal
ecosystems in many countries. The construction of tourism infrastructure
has both a direct and indirect adverse impact on coastal environments
through infilling, dredging and resuspension of contaminated silts, discharge
of untreated or partially treated sewage, operational leaks, and discharge
of hydrocarbons and waste dumping. Sand dunes, an important component
of coastal ecosystems in the region, have also been eroded as a result
of tourism activities.
Sediment load in the coastal zones of South Asia is high, mainly as a
result of soil erosion caused by poor land-use practices and construction
activities. Annually, about 1.6 billion tonnes of sediment reach the Indian
Ocean from rivers flowing from the Indian sub-continent. The total sediment
load of the river system of Bangladesh alone amounts to about 2.5 billion
tonnes, of which the Brahmaputra carries 1.7 billion tonnes and the Ganges
0.8 billion tonnes (UNEP 1987). Coastal erosion is severe in many areas
including the Andaman coast, the Gulf of Thailand, Japan and the PICs.
| Managing ballast water discharges in Australia
The annual discharge of ballast water in Australian coastal waters
is about 150 million tonnes from international vessels and 34 million
tonnes from coastal vessels. A major incursion of black-striped
mussels in Darwin Harbour in early 1999 prompted the establishment
of a National Task Force on the Prevention and Management of Marine
Pest Incursions. A major recommendation of the task force was the
establishment of a single national management regime for vessels.
Its recommendations are implemented through the National Introduced
Marine Pests Coordination Group which was established under the
Ministerial councils for environment, fisheries and aquaculture,
and transport. The Consultative Committee on Introduced Marine Pest
Emergencies, a mechanism for emergency responses to introduced marine
pests, was introduced in 2000.
Since 1990 the Australian Quarantine and Inspection Service (AQIS)
has adopted voluntary guidelines and measures to manage ballast
water. In July 2001, Australia introduced mandatory ballast water
management for international vessels entering its waters. Vessels
are assessed by AQIS: high risk vessels are required to fully exchange
ballast water at sea, while low risk vessels are allowed to exchange
within coastal waters.
Source: Environment Australia 2001