A preliminary survey of organic pollution of shellfish in Tolo Harbour,Hong Kong

A preliminary survey on the contamination of clams and sea-waters in various towns in Tolo Harbour was carried out using bacteriological tests. The ‘percentage clean’ method and the ‘most probably number’ method were employed. The pH, salinity and temperature of the seawater were also tested in the field. It was discovered that the number of coliform bacteria obtained by the ‘percentage clean’ was zero in both seawater and clams from all sites including the control. The ‘most probable number’ indicated that the water and the clam tissue collected in the three sites in Tolo Harbour ranged from 15–1,100/100 ml in the water and 825–11,000/g in the clams compared with 0/100 ml and 115/g of the control site. Due to the high level of organic pollution in Tolo Harbour, improvement of the sanitary situation is urged. Cultivation of clams collected in this area in clean and sterilized water for a few days before consumption is recommended.