THE ENVIRONMENT
declaration of the North Western Water Control Zone in 1992, the protection of the Water Pollution Control Ordinance extended to all new towns.
Despite better planning in the new towns, some water pollution still occurs. In Tolo Harbour, a major part of the pollution comes from connections of effluents from industrial and commercial areas to storm water drains. The nutrient rich effluent has contributed to poor water quality in the harbour. A tunnel that will divert reclaimed water from Sha Tin and Tai Po to a less sensitive area, completing the major elements of the Tolo Harbour Action Plan, broke through in May 1992. This will produce immense benefits to Tolo when it is operational in 1993.
Another pollution problem is heavy metal from industrial discharges. High concen- trations of heavy metals upset the performance of the government's sewage treatment works, thereby adding to environmental pollution. However, statutory controls have been successful in reducing pollution loading in the various water control zones.
Rural areas and the sea
In the developed parts of the New Territories, water pollution in many rivers and streams is still severe. Some streams have recorded a degree of pollution equivalent to 10 times the strength of raw domestic sewage, and a thick, foul crust on streams is common. This pollution is a serious health risk where it passes through towns such as Yuen Long and Tuen Mun.
The cause of much of this pollution is the territory's livestock industry. Before 1987, the total amount of waste produced annually by about 0.7 million pigs and 1.2 million poultry in Hong Kong was 840 000 tonnes. This was equivalent to the pollution load of the raw sewage from a population of two million people. Most of it ended up in Hong Kong's small streams and rivers and then the sea. By the end of 1992, this load had been reduced to only 360 000 tonnes.
In the sea, away from the urban areas and confined bays, water quality objectives are met most of the time. However, dredging and dumping as part of the process of land formation and construction imposed severe pressure during 1992. Extensive areas of muddy water were visible at times, and fishermen in some areas complained of reduced fish catches. Illegal dumping and short dumping (outside the designated areas) of spoil damage marine life.
Bathing beaches have been an important recreational resource in Hong Kong for many years, and because of their attractive locations they have acted as a magnet for high quality housing. This has caused serious pollution in the past, but most of Hong Kong's beaches are now fit for swimming. The government uses strict standards for bacteria levels at bathing beaches. The Environmental Protection Department devised these standards, which relate to the degree of sewage pollution, in a very thorough study of the health risk that bathers face. The following table shows how beaches were classified in 1990, 1991 and 1992. Unfortunately, complaints occur even at beaches that are free from sewage pollution, usually because of floating litter and occasionally because of slime caused by algae.
Beach grade
Good
Fair
364
Poor
Very poor
Health risk cases per 1 000 swimmers
Undetectable Under 10
10 to 15 Over 15
Number of beaches
1990
1991
1992
22
27
22
26
19
22
6
7
9
2
3
3