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Following is a question by the Hon Ronny Tong and an oral reply by the Secretary for the Environment, Transport and Works, Dr Sarah Liao, in the Legislative Council meeting today (June 7) :
Question:
I received complaints from some fish farmers about the sharp increase in the number of incidents in which fish and shell fish died collectively in the fish culture zones of Tolo Harbour, compared to the corresponding figures in the past years. As the laying of natural gas pipelines in Tolo Harbour last year might have stirred up the toxic heavy metals deposited in the seabed, and the test results of the Agriculture, Fisheries and Conservation Department ("AFCD") last year indicated that the concentration of cadmium, a heavy metal, in shell fish samples collected from such area was more than twice the permitted concentration specified for food in the Food Adulteration (Metallic Contamination) Regulations (Cap 132 sub. leg. V), the fish farmers requested the Environmental Protection Department ("EPD") to take soil samples for testing from two to three metres beneath the seabed near the works site. EPD turned down the request on grounds of insufficient resources and the lack of drilling equipment and technical staff in this respect. On the other hand, the test results of AFCD showed that such fish and shell fish were mainly infected by bacteria, virus and parasites. In this connection, will the Government inform this Council:
(a) whether EPD has considered adopting other methods such as using hammer grabs, deploying divers or other means for taking soil samples for testing from two to three metres beneath the seabed;
(b) how it will solve the problem relating to the lack of resources for EPD to conduct such tests; and
(c) how it will help the fish farmers solve the problem of the infection of a large amount of fish and shell fish with bacteria, virus and parasites?
Reply:
Madam President,
My reply to the three questions raised is as follows:
(a) The Environment Protection Department (EPD) considers that testing the surface sediment samples collected next to the pipeline is adequate to determine whether the exceedance of cadmium in pearl oysters at Lo Fu Wat Pearl Farm was caused by the pipelaying works. This is because only sediment stirred up during jetting and deposited on the surface next to the pipeline can possibly be dispersed and drifted to the pearl farm. During the drifting process, the sediment will be dispersed and diluted. Thus, the sediment samples next to the pipeline represent the worst scenario. Moreover, unless heavy metal exists naturally in the sediment, the concentration of heavy metal is usually higher on the surface if the heavy metal is deposited onto the seabed as a result of human activities. For this reason, EPD considers that there is no technical justification to take sediment samples at a depth of 2 to 3m below the seabed. Besides, it is not feasible to take such sediment samples by means of a hammer grab or by deploying divers.
The Hong Kong and China Gas Company Limited or its contractor is required by the Environmental Permit issued under this project to monitor the environmental impacts closely. EPD has also conducted independent monitoring, including carrying out site inspections and water quality monitoring by taking water samples from Tolo Harbour for testing. All the data collected indicate that the pipelaying project does not induce any adverse impact on the water quality of Tolo Harbour.
(b) EPD monitors the heavy metal content of the marine sediment in Tolo Harbour regularly for over a decade. Thus, there are sufficient data to evaluate whether the pipelaying project causes any heavy metal contamination of the marine sediment. Nonetheless, when resources permitted, EPD had arranged the collection of grab samples of surface sediment next to the pipeline for testing by the Government Laboratory with a view to allaying the concerns of the fishermen. The test results confirm that the cadmium content of the sediment samples is comparable to that obtained by EPD under its long term monitoring programme.
(c) In the natural environment, there exists a certain amount of pathogens, including bacteria, virus and parasites in the water body. In mariculture zones, fish may be under stress and more prone to infection under crowded environment. In addition, there are other external factors, which may subject the fish to health risk including sudden change in water quality, malnutrition, skin injury resulting from hitting or abrasion, causing an increase in the chance of fish infection or death induced by pathogens. Moreover, parent fish may be carriers of pathogens, resulting in the transmission of diseases from the mother fish to their offspring at birth.
Under the "Fish Health Inspection Programme", the Agriculture, Fisheries and Conservation Department (AFCD) conducts health inspections of cultured fish at marine fish culture zones on a regular basis. This programme aims to offer assistance on fish culture and identify fish diseases at the earliest opportunity with a view to preventing the transmission of diseases and resulting fish death. Moreover, AFCD offers suggestions to fishermen on the selection of healthy fries and on demanding the importers to provide health certificates issued by the country of origin. AFCD also assists fishermen to inspect imported fries specimen and conducts virus tests to prevent the fries from pathogenic infection through their mothers. Besides, AFCD organises regular training and on-farm demonstrations for, and distributes leaflets and guidelines to the fishermen on good mariculture practises and disease prevention.
Apart from the fish health inspections conducted by the AFCD, fishermen should also carry out simple inspection on their fish every day. Should there be any suspected infection, the fish concerned must be isolated immediately and assistance from the Veterinary Officers of the AFCD should be sought for proper treatment as soon as possible.
Ends/Wednesday, June 7, 2006
Issued at HKT 14:20
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