THE ENVIRONMENT
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Water pollution has increased with urban development. The Environmental Protection Department (EPD) has estimated that, due to the many expedient con- nections between foul sewerage and storm drains, only half the city's sewage million tonnes a day — gets any treatment before it flows into the sea. This has a severe impact on confined areas such as typhoon shelters. In the worst of these, such as the Kowloon Bay typhoon shelter alongside Hong Kong International Airport, foul-smelling and toxic gases emerge from the polluted water. The first stage of the East Kowloon sewerage improvement scheme has reduced the organic pollution load entering the typhoon shelter by 35 tonnes a day and later stages will remove all remaining polluting discharges.
Water quality in the harbour has remained poor over the past decade. Dissolved oxygen, a good indicator of water quality, is about 50 per cent saturation, reflecting the large quantity of organic material poured into the harbour. Stage 1 of the Strategic Sewage Disposal Scheme is under construction and will significantly reduce sewage pollution in the main part of the harbour when completed in mid-1997. Meanwhile, enforcement of the Water Pollution Control Ordinance in Phase I of the Victoria Harbour Water Control Zone is taking effect and control has been extended to cover Phase II of the same zone.
Comprehensive controls on the handling and disposal of chemical waste began in May 1993 with the opening of the chemical waste treatment centre and full implementation of the Waste Disposal (Chemical Waste) (General) Regulations. Hong Kong can now stop the widespread malpractice of dumping bulk chemical waste into the territory's sewers and surface waters. The total toxic metal discharged into Victoria Harbour was cut by 3 000 tonnes per day between May 1993 and the end of 1995.
The Environment of New Towns
The development of what were formerly rural areas of small fishing and market towns has helped to sustain economic growth in Hong Kong. To some extent, the territory's new towns face the same environmental problems as the old urban areas. They have been better planned, with more space, sewerage and waste disposal facilities, but water pollution exists in rivers, streams and the sea due to increased human activities. The inland and coastal waters of all new towns have now been declared Water Control Zones and discharges in these areas are controlled under the Water Pollution Control Ordinance.
Nevertheless, Tolo Harbour, a landlocked inlet with a poor flushing capacity, has a very limited ability to assimilate pollutants. Most pollution comes from the two municipal treatment works at Sha Tin and Tai Po, effluent from industrial and commercial areas reaching storm water drains, sewage discharges from unsewered village areas, mariculture zones and leachate from the Shuen Wan Landfill.
Though it remains unsatisfactory, the decline in water quality appears to have been halted. Many unauthorised or expedient connections have been rectified through the enforcement of the ordinance. Direct sewage discharges from the villages into the surface water will be gradually eliminated by the implementation of the Tolo Harbour Sewerage Master Plan. The most significant contributor to nutrient pollution in Tolo Harbour has been treated sewage from the Sha Tin and Tai Po sewage treatment works. In 1995, the government started pumping high-quality effluent from both these works through a long tunnel under the Kowloon hills and
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