THE ENVIRONMENT
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Wan, Chai Wan, Junk Bay and the vicinity of Kowloon Bay; plus a ship-to-ship domestic refuse collection service. In July, two motorised sampans were added to the Aberdeen Harbour service and two fleets - each consisting of a mechanised cargo boat and three non-motorised sampans – began operating on a flexible working area basis within Victoria Harbour. Both are expected to lead to a definite improvement in the cleanliness of these waters. The harbour cleansing service is carried out by more than 50 mechanised cargo boats and sampans owned and crewed by private contrac- tors, but supervised by staff of the Pollution Control Unit. Public tenders for these services are invited annually, ensuring a fair and reasonable cost to the government. An average of 16 tonnes of wet refuse is lifted from the sea each working day while the ship-to-ship service collects about 2 tonnes of refuse daily from ocean-going ships. Medium-term proposals call for establishing a mechanised and fully integrated sea-land refuse collection and disposal system covering the entire waters of Hong Kong and the phasing out of manually-operated services.
In the seven years since it was formed, the Pollution Control Unit has successfully prosecuted many who have caused pollution; fines totalling about $150,000 were imposed during the year.
The Marine Pollution Section of the Agriculture and Fisheries Department resumed its fortnightly plankton sampling programme in Tolo Harbour in late 1976 in colla- boration with the marine science laboratory of the Chinese University of Hong Kong. Sampling at the innermost station was abandoned as reclamation work approached in April, but a station was added on a new spoil dumping ground off Flat Island. A number of red tides were observed in the inner harbour in the spring, and a major fish kill occurred in Tai Po Hoi at the end of May after heavy rains washed accumulated organic wastes out of the Lam Tsuen River.
A new programme of fortnightly plankton sampling, initiated late in 1976, covers 12 stations in Port Shelter, Junk Bay, Victoria Harbour and its western and south- western approaches. Intensive sampling was undertaken in Junk Bay in July and August to investigate its long-term capacity to receive effluent discharges.
A benthic or sea-bottom survey, undertaken in collaboration with a research student from the University of Hong Kong, was completed in August and the results have been presented in thesis form. An additional survey of Tolo Harbour was made as a part of the university's malacological workshop in early April. Surveys of sea urchin and sea fan abundance on rocky bottoms are being made in co-operation with amateur divers as a local contribution to Underwater Conservation Year.
Long-term monitoring of toxic metal loads in inshore fish and shellfish was initiated in the autumn as a sequel to last year's preliminary survey. The major object is to determine long-term trends in contamination levels.
In an effort to curb pollution that farmers cause by hosing and dumping livestock manures into New Territories streams and watercourses, the Agriculture and Fisheries Department Waste Treatment Unit spent most of the year tackling problems the polluters will face when they change their unsatisfactory manure-handling and dis- posal practices.
Pilot schemes run by the department to help solve these problems include a rotary-type drier at Pat Heung that continued to convert poultry manure into fertiliser, and a batch-type drier at Sai Kung that was commissioned in the last half of the year.