THE ENVIRONMENT
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investigation of pollution in industrial, residential and other special localities which cannot be covered by fixed monitoring sites. A two-month study in the Tsuen Wan industrial area revealed high levels of pollution at street level. A similar study in the Southern District of Hong Kong indicated generally acceptable air quality. The data from the air monitoring work is being used, inter alia, for the preparation of Air Quality Management Plans.
Monitoring of the lead levels in airborne particulates and roadside dust continued, with results indicating a general downward trend reflecting the reduction in the amount of lead in petrol. Studies of air quality under flyovers and measurement of odours due to sulphur compounds were also undertaken.
The Environmental Protection Department runs a comprehensive programme for monitoring marine and fresh water quality throughout the territory. The department assesses the quality of the water against a series of Water Quality Objectives. The objectives for inland waters in the Tolo Harbour and Channel Water Control Zone were approved by EPCOM and published in the Government Gazette.
Water quality throughout most of Hong Kong's marine waters is good to very good. Even in Victoria Harbour, despite its heavy loading of sewage, the required minimum dissolved oxygen level of 50 per cent saturation is rarely breached. There are, however, a number of pollution blackspots - the typhoon shelters, especially Kowloon Bay, Rambler Channel near Tsuen Wan, inner Tolo Harbour and inner Deep Bay - all of which require urgent pollution control action.
Inland monitoring shows that many rivers and streams are heavily contaminated with livestock waste, sewage and industrial effluents. In some cases, bacteria counts are dangerously high. These results underline the urgent need for control of livestock waste and the provision of more mains sewerage.
All but three of Hong Kong's gazetted (that is, publicly-managed) bathing beaches meet the water quality objectives for beaches most of the time, and are therefore judged to be acceptable for swimming. Over the past five years, the beaches on the south side of Hong Kong Island, at Deep Water Bay, Repulse Bay and Stanley among others, have shown a steady trend towards poorer water quality. These are some of Hong Kong's most attractive and popular bathing beaches, and monitoring has clearly demonstrated the need for urgent pollution control measures to keep the water quality within reasonably safe limits.
During 1987, the EPD and the Department of Community Medicine at the University of Hong Kong continued their joint investigation into the link between beach water quality and health. Preliminary results suggest that the chances of suffering a minor ailment after swimming at Hong Kong's beaches are relatively low, compared with similar studies carried out overseas. This summer, a further 70 000 beach users were questioned to find out if they suffered any symptoms that might be associated with swimming. At the same time 1 000 samples were analysed for about 6 500 bacteria counts. When the project is complete and the results interpreted, the EPD will be able to set a standard for bathing beach waters which the public can rely on to protect health.
Waste arisings are now monitored annually and the information is used to plan future waste disposal facilities. In 1987, waste quantities increased by 11 per cent from an average of 8 100 tonnes a day in 1986 to 9 000 tonnes a day. This represented an increase of five per cent collected by the Urban and Regional Services departments, an increase of 25 per cent collected by the private sector and a 22 per cent increase in construction waste.