Hong Kong Regulations

TOLO HARBOUR AND CHANNEL WATER CONTROL ZONE STATEMENT OF WATER QUALITY OBJECTIVES - SCHEDULE 1

Water Quality Objective Subzone A. AESTHETIC APPEARANCE

        (i)    Odours, taints and colours Waste discharges shall cause no
               noxious or offensive odour or offensive taint or colour in
               either waters or edible aquatic organisms in the subzone to be
               present in concentrations detectable by bioassay or
               organoleptic tests.

        (ii)   Visible matter Waste discharges shall cause no visible foam,
               oil, grease, scum, litter or other objectionable matter in
               waters of the subzone.

   (i)  Harbour subzone.

   (ii) Buffer subzone.

   (iii) Channel subzone.

   (i)  Harbour subzone

   (ii) Buffer subzone

   (iii) Channel subzone B. BACTERIA The level of Escherichia coli should not
        exceed 610 per 100 mL, calculated as the geometric mean of all samples
        collected in one calendar year. (i) Secondary contact recreation
        subzone

   (ii) Fish culture subzones
(L.N. 454 of 1991)

C. CHLOROPHYLL-A Waste discharges shall not cause the level of chlorophyll-a
in waters of the subzone to exceed 20 milligrams per cubic metre, calculated
as a running arithmetic mean of 5 daily measurements for any single location
and depth.

Waste discharges shall not cause the level of chlorophyll-a in waters of the
subzone to exceed 10 milligrams per cubic metre, calculated as a running
arithmetic mean of 5 daily measurements for any single location and depth.

Waste discharges shall not cause the level of chlorophyll-a in waters of the
subzone to exceed 6 milligrams per cubic metre, calculated as a running
arithmetic mean of 5 daily measurements for any single location and depth.
Harbour subzone.

Buffer subzone

Channel subzone. D. DISSOLVED OXYGEN Waste discharges shall not cause the
level of dissolved oxygen in waters of the subzone to be less than 2
milligrams per litre within two metres of the bottom, or to be less than 4
milligrams per litre in the remainder of the water column.

Waste discharges shall not cause the level of dissolved oxygen in waters of
the subzone to be less than 3 milligrams per litre within two metres of the
bottom, or to be less than 4 milligrams per litre in the remainder of the
water column.

Waste discharges shall not cause the level of dissolved oxygen in waters of
the subzone to be less than 4 milligrams per litre at any point in the water
column.
Harbour subzone

Buffer subzone

Channel subzone. E. LIGHT PENETRATION No changes in turbidity, suspended
material, colour or other parameters arising from waste discharges shall
reduce light transmission by more than 20 per cent of the normal level in the
subzone at any location or any time.

No changes in turbidity, suspended material, colour or other parameters
arising from waste discharges shall reduce light transmission by more than 15
per cent of the normal level in the subzone at any location or any time.

No changes in turbidity, suspended material, colour or other parameters
arising from waste discharges shall reduce light transmission by more than 10
per cent of the normal level in the subzone at any location or any time.
Harbour subzone

Buffer subzone

Channel subzone F. pH Waste discharges shall not cause the normal pH range of
any waters of the subzone to be extended by greater than +/- 0.5 pH units at
any time.

Waste discharges shall not cause the normal pH range of any waters of the
subzone to be extended by greater than +/- 0.3 pH units at any time.

Waste discharges shall not cause the normal pH range of any waters of the
subzone to be extended by greater than +/- 0.1 pH units at any time.
Harbour subzone

Buffer subzone

Channel subzone G. SALINITY Waste discharges shall not cause the normal
salinity range of any waters of the subzone to be extended by greater than +/-
3 parts per thousand at any time. (i) Harbour subzone

   (ii) Buffer subzone

   (iii) Channel subzone

H. SETTLEABLE MATERIAL Waste discharges shall give rise to no bottom deposits
or submerged objects which adversely influence bottom-living communities,
alter the basic Harbour geometry or shipping channels, present any hazard to
shipping or diving activities, or affect any other beneficial use of the
waters of the subzone.

   (i)  Harbour subzone

   (ii) Buffer subzone

   (iii) Channel subzone I. TEMPERATURE Waste discharges shall not cause the
        natural daily temperature range in waters of the subzone to be
        extended by greater than +/- 1.0℃ at any location or time. The rate
        of temperature change shall not exceed 0.5℃ per hour at any
        location, unless due to natural phenomena. (i) Harbour subzone

   (ii) Buffer subzone

   (iii) Channel subzone J. TOXICANTS Waste discharges shall not cause the
        toxicants in waters of the subzone to attain such a level as to
        produce significant toxic effects in humans, fish or any other aquatic
        organism, with due regard to biologically cumulative effects in food
        chains and to toxicant inter- actions with each other. (i) Harbour
        subzone

   (ii) Buffer subzone

   (iii) Channel subzone