PORT SHELTER WATER CONTROL ZONE STATEMENT OF WATER QUALITY OBJECTIVES

PORT SHELTER WATER CONTROL ZONE STATEMENT OF WATER QUALITY OBJECTIVES

PORT SHELTER WATER CONTROL ZONE STATEMENT
OF WATER QUALITY OBJECTIVES

(Cap. 358, section 5)

[28 July 1989]

L.N. 251 of 1989 -

The water quality objectives set out in the first column of Schedule 1 have
been established for those parts of the Port Shelter Water Control Zone defined in
Schedule 2 set opposite those water quality objectives in the second column of
Schedule 1.

SCHEDULE 1

Water Quality Objective Part or parts of Zone

A. AESTHETIC APPEARANCE
(a) Waste discharges shall cause no objectionable Whole Zone
odours or discolouration of the water.
(b) Tarry residues, floating wood, articles made of Whole Zone
glass,plastic, rubber or of any other substance
should be absent.
(C) Mineral oil should not be visible on the surface. Whole Zone
Surfactants should not give rise to a lasting foam.
(d) There should be no recognisable sewage-derived Whole Zone
debris.
(e)Floating, submerged and semi-submerged objects of Whole Zone
a size likely to interfere with the free movement of
vessels,or cause damage to vessels, should be
absent.
(j) Waste discharges shall not cause the water to Whole Zone
contain substances which settle to form
objectionable deposits.
B. BACTERIA
(a) Waste discharges shall not cause the level of Secondary Contact
Escherichiacoli to exceed 1000 per 100 mI, in Recreation Subzone
more than 60% of the samples collected during the
whole year.
(b) The level of Escherichia coli should not exceed Bathing Beach Subzones
1000 per100 mI, calculated as the running median
of the most recent5 consecutive samples. Samples
should be taken3 times in one calendar month at
intervalsof between 3 and 14 days. The sampling
programme extends from March to October
inclusive in any year.
(c) The level of Escherichia coli should not exceed Inland waters
1000 per100 mI, calculated as the running median
of themost recent 5 consecutive samples taken at
intervals of between 7 and 21 days.





Water Quality Objective Part or parts of Zone

C. COLOUR
Waste discharges shall not cause the colour of water to Inland waters
exceed 50 Hazen units.
D. DISSOLVED OXYGEN
(a) Waste discharges shall not cause the level of dissolved Marine waters excepting
oxygen to fall below 4 mg per litre for 90% of the Fish Culture Subzones
sampling occasions during the year; values should be
calculated as the water column average (arithmetic
mean of at least 3 measurements at 1 m below
surface, mid-depth and 1 m above seabed). In
addition, the concentration of dissolved oxygen
should not be less than 2 mg per litre within 2 m ofthe
seabed for 90% of the sampling occasions during the
year.
(b) The dissolved oxygen level should not be less than Fish Culture Subzones
5 mg per litre for 90% of the sampling occasions
during the year; values should be calculated as
water column average (arithmetic mean of at least
3 measurements at 1 m below surface, mid-depth and
1 m above seabed). In addition, the concentration of
dissolved oxygen should not be less than 2 mg per litre
within 2 m of the seabed for 90% of the sampling
occasions during the year.
(C) Waste discharges shall not cause the level of dissolved Inland waters
oxygen to be less than 4 mg per litre.
E. pH
(a) The pH of the water should be within the range of Marine waters excepting
63-8.5 units. In addition, waste discharges shall not Bathing Beach Subzones
cause the natural pH range to be extended by more
than 0 .2 units.
(b) The pH of the water should be within the range of Bathing Beach Subzones
6.0-9.0 units for 95% of samples. In addition, waste
discharges shall not cause the natural pH range to be
extended by more than 0.5 units.
(e) Waste discharges shall not cause the pH of the water Ho Chung (A) Subzone
to exceed the range of 63-8.5 units.
(d) The pH of the water should be within the range of Other inland waters
6.0-9.0 units.
F. TEMPERATURE
Waste discharges shall not cause the natural daily tem- Whole Zone
perature range to change by more than 2.0C
G. SALINITY
Waste discharges shall not cause the natural ambient Whole Zone
salinity level to change by more than 10%.
H. SUSPENDED SOLIDS
(a) Waste discharges shall neither cause the natural Marine waters
ambient level to be raised by 30% nor give rise
to accumulation of suspended solids which may
adversely affect aquatic communities.
(b) Waste discharges shall not cause the annual median of Inland waters
suspended solids to exceed 25 mg per litre.





Water Quality Objective Part or parts of Zone

1. AMMONIA
The ammonia nitrogen level should not be more than Whole Zone
0.021 mg per litre, calculated as the annual average (arith-
metic mean), as unionised form.
J. NUTRIENTS
(a) Nutrients shall not be present in quantities sufficient Marine waters
to cause excessive or nuisance growth of algae or other
aquatic plants.
(b) Without limiting the generality of objective (a) above, Marine waters
the level of inorganic nitrogen should not exceed
0. 1 mg per litre, expressed as annual water column
average (arithmetic mean of at least 3 measurements
at 1 m below surface, mid-depth and 1 m above
seabed).
K. 5-DAY BIOCHEMICAL OXYGEN DEMAND
Waste discharges shall not cause the 5-day biochemical Inland waters
oxygen demand to exceed 5 mg per litre.
L. CHEMICAL OXYGEN DEMAND
Waste discharges shall not cause the chemical oxygen Inland waters
demand to exceed 30 mg per litre.
M. DANGEROUS SUBSTANCES
(a) Waste discharges shall not cause the concentration of Whole Zone
dangerous substances in the water to attain such levels
as to produce significant toxic effects in humans, fish
or any other aquatic organisms, with due regard to
biologically cumulative effects in food chains and to
toxicant interactions with each other.
(b) Waste discharges of dangerous substances shall not Whole Zone
put a risk to any designated beneficial uses of the
aquatic environment.
N. PHENOL
Phenols shall not be present in such quantities as to Bathing Beach Subzones
produce a specific odour, or in concentrations greater than
0.05 mg per litre as C6H.0H.
0. TURBIDITY
No changes in turbidity or other factors arising from waste Bathing Beach Subzones
discharges shall reduce light transmission substantially
from the normal level.

SCHEDULE 2

In this statement-

'bathing beach subzone' means a bathing beach that is specified in the Fourth Schedule to the Public Health and
Municipal Services Ordinance (Cap. 132) and situated in the Port Shelter Water Control Zone;

'fish culture subzone' means a fish culture zone that is designated in the Fish Culture Zone (Designation) Order (Cap.
353 sub. leg.) and situated in the Port Shelter Water Control Zone;





'Ho Chung (A) subzone' means that part of the catchment of the Ho Chung River delineated on
the Map and which delineated part is marked HC(A);

'Map' means a 1:25 000 map marked PSWCZ signed by the Secretary for Lands and Works,
Lands and Works Branch, on 6 July 1989 and deposited in the Land Office, Victoria;

'marine waters' means the waters within the Port Shelter Water Control Zone boundary below
the high water mark;

'Secondary Contact Recreation Subzone' means an area delineated as such on the Map, except
where the area is designated as a bathing beach subzone or a fish culture subzone.

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