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SECTION
5 ASSIMILATIVE CAPACITY CAPITAL STOCK
| 5.2 |
Assimilative
Capacity of Marine Waters |
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| 5.2.3 |
Impacts
and Resource Constraints |
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| 5.2.3.1 |
The
assimilative capacity of marine waters is
directly affected by the inputs of pollutant
loads resulting from anthropogenic activities
but can be offset by anthropogenic efforts
to reduce or treat pollutants using infrastructure
or regulatory programmes. Three types of drivers
will determine the future status of Hong Kong's
marine water quality and its ability to serve
an assimilative capacity function for receiving
future waste inputs. These drivers consist
of pressures on pollutant inputs, pressures
on the natural assimilative capacity, and
pressures on the assimilative capacity enhancers,
each of which is discussed below. |
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Pressures
on Pollutant Inputs
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| 5.2.3.2 |
As
shown by the energy usage statistics discussed
in Paragraph 3.6.1.10, Hong Kong's industrial
sector has dwindled in recent years and
from this it can be inferred that the share
of the total wastewater load contributed
by industry has also declined. However,
given the expected continued growth of Hong
Kong's population, domestic sewage arisings
will undoubtedly increase with time and
it is likely that the bulk of the growth
in future wastewater volumes will be from
this sector. For the remaining share of
wastewater generated by industrial and commercial
sectors, clean production technologies which
can reduce pollutant loads while simultaneously
producing economic benefits may become increasingly
important. For the domestic sector, technological
solutions will likely be less important
than reductions in freshwater usage which
will translate into smaller, but more concentrated,
domestic wastewater flows. Opportunities
for reduced usage of freshwater resources
are discussed in Paragraphs 3.4.3.4 - 3.4.3.5.
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| 5.2.3.3 |
Pollutant
inputs to marine waters may also arise from
inputs other than wastewater. Dredging and
dredged material disposal activities, if
not managed properly, can create plumes
of suspended sediments and associated depressions
of dissolved oxygen and nutrient elevations.
Existing mechanisms to manage these activities
exist in the form of environmental impact
assessments which are conducted on all major
dredging projects and disposal site designations
prior to operation. These assessments predict
the effects on marine waters and recommend
appropriate mitigation measures and are
thus, in combination with monitoring programmes,
generally effective in preventing adverse
impacts. Hong Kong is a signatory to the
London Convention on the Prevention of Marine
Pollution by Dumping of Wastes at Sea through
the Mainland of China and adheres to fully
compliant and international best practice
methods in the classification, disposal
and management of contaminated dredged materials
(ERM 1999d).
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| 5.2.3.4 |
Another
type of pollutant input that is currently
being managed is nutrient enrichment from
mariculture operations. The potential for
problems to arise from this enrichment is
being addressed by a remediation programme
conducted in various fish culture zones.
Government has also conducted research on
the causative factors underlying red tides
and plans to establish a phytoplankton monitoring
programme to improve early warning of red
tide outbreaks.
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| 5.2.3.5 |
A
final category of pollutant input to marine
waters is illegal dumping, either of liquid
waste (eg from workshops) into storm drains,
or of liquid or solid waste into marine waters
from vessels or land-based sources. The former
issue is being addressed through greater enforcement
of the Water Pollution Control Ordinance (Cap
358) and by the operation of the Chemical
Waste Treatment Facility at Tsing Yi which
now provides an appropriate disposal route
for many types of liquid waste that were previously
disposed through the drainage system. It is
worth noting however, that the discharge of
domestic waste effluents from small vessels
in typhoon shelters and open water is not
subject to WPCO control. |
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| 5.2.3.6 |
The
issue of illegal dumping of waste at sea is
now controlled under the Dumping at Sea Ordinance
(Cap 466) and recent enforcement actions (ie
a Po Toi restaurant owner fined $55,000 for
a dumping violation) will likely act as a
deterrent to potential violators. The Chemical
Waste Treatment Facility also serves as a
receiving facility for MARPOL (ie the International
Convention for the Prevention of Pollution
from Ships (MARPOL 73/78)) wastes which include
oil (Annex I), noxious liquid substances (Annex
II), harmful substances in packaged form (Annex
III), sewage (Annex (IV), and garbage from
ships (Annex V). Hong Kong, through the Mainland
of China is a signatory to Annexes I-III and
V of the MARPOL Convention. The issue of casual
littering from vessels or at beaches or other
coastal areas is potentially more problematic
and will require both public education and
penalties to address (see Paragraphs 3.2.2.10
and 4.3.2.9 for further discussions on litter).
Floating rubbish presents a number of aesthetic
and public health problems and removing the
problem is expensive - in 1996 the Marine
Department was allocated $50.4 million to
modernise its refuse collection and scavenging
fleet (ISD 1998) which is reported to collect
200 tonnes of marine refuse per day (EPD 1998c).
It is difficult to foresee trends in the issue
of illegal dumping since little is known about
current, unrecorded practices. |
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