THE ENVIRONMENT
Kowloon and the Rambler Channel near Tsuen Wan), the inner parts of embayments (Tolo Harbour, Port Shelter, Junk Bay and Deep Bay), and typhoon shelters. Trends of water quality deterioration have been found in some of these blackspots, in particular Victoria Harbour and Tolo Harbour. In Tolo Harbour, red tides occur frequently, sometimes killing the fish.
As shown by the monitoring results, many rivers and streams are heavily contaminated with livestock waste, sewage and industrial effluents. In some cases, bacteria numbers are dangerously high in the river estuaries. Yet, during the year, slight improvements were detected in some watercourses such as Lam Tsuen, Tai Po, Fo Tan and Shing Mun rivers, mainly as a result of the implementation of the WPCO in the Water Control Zones, clearing of squatter areas, and the interception of sewage from villages.
The microbial water quality at many of Hong Kong's beaches has been deteriorating for a number of years. The deterioration was caused mainly by livestock waste and raw or partially-treated sewage entering the sea at or close to the beaches. The increasingly-large number of faecal bacteria in these discharges contaminated the water at many beaches, posing a health risk to swimmers.
In order to determine the risk of swimming at Hong Kong beaches, a ranking system was developed based on the expected rates of gastroenteritis and skin diseases associated with different degrees of faecal pollution of beach water. The degree of faecal pollution is assessed by regular monitoring of the concentrations of indicator bacteria in the beach water and the rankings are determined by examining the results for each beach averaged over the whole swimming season. Under the system, beaches are classified as good, meaning that the expected gastroenteritis and skin symptom rate is zero; acceptable, meaning that the rate is less than ten per thousand swimmers; barely acceptable, meaning that the rate is up to fifteen per thousand; and unacceptable, meaning that the risk rate is higher than this. The new ranking system for beaches has been accepted by the beach management authorities and was first used in 1988. In 1989, the number of gazetted bathing beaches classified as good was 15; acceptable, 18; barely acceptable, seven and unacceptable, two.
In addition to undertaking the annual ranking of beaches, the EPD publishes fortnightly during the bathing season a 'snapshot' of beach water quality. This takes the form of grading the beaches as A (good), B (acceptable) and C (poor). The snapshot is based on the most recent monitoring data and is intended to give the public rapid feedback on the latest water quality at the bathing beaches.
Among the beaches where water quality has declined in past years were some very popular ones on the south side of Hong Kong Island, such as Repulse Bay, Middle Bay and Stanley main beach. They were polluted largely by sewage from private developments (which either did not possess, or did not properly maintain, sewage treatment facilities) and by sewage leaking from defective sewerage. In 1989, 'first-aid' measures were implemented at several of the most affected beaches on Hong Kong Island, such as Repulse Bay and Middle Bay, and the deterioration has been halted. These measures involved mainly the interception and diversion of sewage which flowed into the beaches, as well as repairs to existing sewerage. This success must be considered temporary and lasting improvements will not be achieved until a comprehensive sewerage network is installed.
Improvements were also achieved as a result of the implementation of the livestock waste control scheme. At Angler's Beach and Silvermine Bay, which were graded 'unacceptable' after the 1988 bathing season, the water quality showed a significant improvement during 1989 and these two beaches will be open to swimmers in 1990.
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