THE ENVIRONMENT
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In order to assess 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 abundance 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 no more than 10 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. For the 1991 bathing season the number of bathing beaches classified as good was 27; acceptable 19; barely acceptable 7, and unacceptable, 3.
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 1 (good), 2 (fair), 3 (acceptable) and 4 (poor). The snapshot is based on the most recent monitoring data and is intended to provide feedback to the public on the latest water quality at the bathing beaches.
Some very popular beaches on the south side of Hong Kong Island, such as Repulse Bay, Middle Bay and Stanley main beaches were among the ones showing declining water quality in the past. They were polluted as a result of the leakage of sewage from defective sewerage, the lack of sewage treatment facilities and improper maintenance of some treatment facilities. In 1989, 'first-aid' measures were implemented at several of the most affected beaches and as a result, the deterioration was halted, and water quality at these beaches during the 1991 bathing season was good. The measures were, however, of a stop-gap nature involving the interception and diversion of sewage which flowed into the beaches, and repairs to existing sewerage. The success must therefore be considered temporary and lasting improvements will not be achieved until the comprehensive sewerage network is installed.
Following the implementation of the livestock waste control scheme a significant improvement of the beach water quality at Silvermine Bay was achieved. The beach, which was graded 'unacceptable' after the 1988 bathing season, was re-opened to swimmers at the beginning of the 1990 season. During the last two years the water quality at this beach has continued to improve.
Wastes
Municipal solid waste arisings are monitored biannually to collect up-to-date information for planning future waste disposal facilities. Compared with the 1990 arisings, waste quantities increased by 51 per cent to 23 500 tonnes per day in 1991. Significant growth by 92 per cent was observed for construction waste while the quantities of domestic waste, industrial waste and commercial waste increased only moderately by one per cent, 10 per cent and six per cent respectively. The general increase in waste arisings reflects the continued economic growth, particularly in the construction industry.
Local waste recovery activities continued to play an important role in waste management, resulting in the export of substantial quantities of recovered waste materials for recycling overseas. A total of 1.3 million tonnes of waste materials including waste paper, metals and plastic were exported in 1991, generating export earnings of $2.3 billion. Local recycling is known to be active, although reliable statistics are difficult to obtain.