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Concentrations of copper, zinc, cadmium and lead in rabbitfish (Siganus oramin) collected in Victoria Harbour, Hong Kong
Pergamon
0025--326X(95)00136-0
Marine Pollution Bulletin, Vol. 31, Nos 4--12, pp. 277-280, 1995 Copyright © 1995 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0025-326X/95 $9.50 + 0.00
Concentrations of Copper, Zinc, Cadmium and Lead in Rabbitfish (Siganus oramin) Collected in Victoria Harbour, Hong Kong KING MING CHAN
Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong
The urban area of Hong Kong supports a population of about 4 million people, with an annual production of several hundred million tonnes of untreated domestic and industrial effluent. This causes significant marine pollution problems in Victoria Harbour. Moreover, urban runoff also brings pollutants to Victoria Harbour. This paper presents preliminary data on the concentrations of heavy metals from different parts of the rabbitfish (Siganus oramin) taken from Hung Horn, Wan Chai and the Central Ferry Pier, close to urban and sewage outfalls in Victoria Harbour, from June to September 1983. Metal concentrations in the seawaters and from the gills, viscera, vertebrae and muscle were determined by atomic absorption spectrophotometry. Concentrations of copper, zinc and lead in the muscle were found to be the lowest in the muscle as compared with other parts of the body (cadmium concentrations were similar in muscle and viscera), but concentrations were nevertheless still high (mean_+SD, dry weight): 5.7_4.0 ppm for copper, 66.6_+31.8 ppm for zinc, 3.3___1.1 ppm for cadmium and 19.1+__6.3 ppm for lead. Cadmium and lead concentrations in the rabbitfish samples of this study were significantly higher than those previously reported in fish from the nearby Pearl River estuary.
Two decades ago, seawater concentrations of cadmium, copper, zinc and lead in Victoria Harbour were 180 times, 2.5 times, 2 times and 160 times higher, respectively, than concentrations of these metals in the open ocean (Chan et al., 1974). Copper and zinc bioavailabilities in Victoria Harbour were also reported to be much higher than elsewhere in Hong Kong coastal waters, as reflected by the biomonitor, Saccostrea glomerata (phillips, 1979). This data, together with the report ofYim & Fung (1981) on metal concentrations in marine sediments of Hong Kong, indicated that the uncontrolled dumping of raw sewage, industrial effluent and urban runoff (via nullah drainage) from the urban areas of Hong Kong have caused significant marine pollution problems, which includes metal contamination in Victoria Harbour.
The urban area of Hong Kong supports a population of more than 4 million people, with approximately 300 million tonnes of untreated sewage, including domestic and industrial effluent, produced and discharged into Victoria Harbour annually (Morton, 1976, 1989; Thompson & Ho, 1981). Local hydrological flow was considered to be effective in diluting and flushing this sewage, but several dead-end areas in the harbour, such as the typhoon shelter Kai Tak Nullah which receives poor tidal flushing, were found to have deteriorated seriously (Environmental Protection Department, 1992, 1994). According to the data published in the recent annual reports (Environmental Protection Department, 1993, 1994), it appears that the situation has not improved since the 1970s, as reported by Morton (1976). Metal contamination of sediments in Victoria Harbour has also been monitored. The sediments in Victoria Harbour and the Tseun Wan area were found to be highly contaminated (200-400 ppm or more) with copper, zinc, lead, nickel and other metals (Yim & Fung, 1981; Environmental Protection Department, 1993, 1994). It is believed that film-processing factories, dyeing industries, ship leakage, paint, aerosol from vehicles (roadside dust), etc., are the sources of heavy metals in the urban runoff and sewage discharged into Victoria Harbour. To date, no studies have been published on the effects of metal pollution on fish populations in Victoria Harbour, although reports on the effects of metals on phytoplankton and on metal accumulation in rock oysters, barnacles and mussels have been published (Phillips & Yim, 1981; Thompson & Ho, 1981; Phillips, 1985, 1989; Phillips & Rainbow, 1988). Significantly large accumulations of copper, zinc and lead were found in the tissues of mussel and barnacles (as biomonitors) collected in Victoria Harbour (Phillips & Rainbow, 1988). The present investigation was carried out in 1983, and its aim was to investigate the metal concentrations in the tissues of the rabbitfish (Siganus oramin) collected from Victoria Harbour. Although submarine outfalls discharge sewage beyond the shoreline, seawall outfalls 277
Marine Pollution Bulletin
and nullah drainage outlets are still accessible in inshore marine organisms. In Victoria Harbour, several ferry piers with seawall outfalls and nullah drainage are often popular fishing spots for local people. One of the common species caught is the rabbitfish. This paper investigates the concentrations of copper, zinc, cadmium and lead in various parts of the rabbitfish and in the water samples collected in Victoria Harbour during the summer of 1983.
Results Table 1 shows the metal concentrations in various tissues of the rabbitfish collected from Victoria Harbour. The metal concentrations in the tissues of the rabbitfish collected from the three locations in Victoria Harbour (Fig. 1) were not significantly different (/7 < 0.05, data not shown) from each other as determined by Duncan's multiple range tests (Little & Hills, 1978), and therefore the data were pooled (Table
1). Methods Sampling sites were located on the shores of the central part of Victoria Harbour (Fig. 1). Water samples and fish were collected every 2 weeks, during the period from June to September 1983, at midtide between high and low tide, from Hung Hom, Wan Chai and Central Pier. Water samples were also collected at Kwun Tong Pier. The fish (four individuals, every 2 weeks from each site) and water samples were collected randomly from 3-15 m away from the seawall outfalls. The water samples were kept in acid-washed polyethylene bottles, acidified immediately after collection with the addition of 1% hydrochloric acid and were processed within 4 h. The fish were frozen at - 2 0 ° C until analysis (within 6 months). Analyses were performed in 1983-1984 in Dr M. H. Wong's laboratory, Biology Department, The Chinese University of Hong Kong. The rabbitfish collected ranged between 6.4 and 9.8 cm long (fork length) and between 6.8 and 16.6 g fresh wt. For tissue analyses, fish were dissected and divided into the gills, viscera, vertebrae and flesh (muscle), all of which were washed with distilled deionized water and dried on paper towels. Samples were dried to constant weight at 105°C and digested in a mixture (0.5:5:1) of sulphuric acid, nitric acid and perchloric acid (Allen et al., 1974), and the metal concentrations of the samples were determined by atomic absorption spectrophotometry using a Varian AA1475 spectrophotometer. For water analyses, samples of between 100 ml and 1 1 were treated to vacuum filtration (0.45 ~tm) to collect suspended solids for metal analyses. The acidified filtrate was also analysed for metal concentrations, by atomic absorption spectrometry using a Varian AA1475 spectrophotometer.
Duncan's multiple range tests were also performed to compare the data listed in Table 1. Lead and cadmium concentrations were found to be higher (p<0.01) in the gills and vertebrae, copper levels highest (p < 0.05) in the viscera and zinc levels lowest (p<0.05) in muscle as compared to the other parts of the body. The concentrations of copper, zinc and lead were found to be the lowest in the muscle as compared to the other parts of the body (cadmium concentrations were similar in muscle and viscera). In comparison with published local data (Phillips et al., 1982; Luk et al., 1990), however, metal concentrations were nevertheless high in the muscle (mean+SD, dry weight): 5.7+4.0 ppm for copper, 66.6-4-31.8 ppm for zinc, 3.3+ 1.1 ppm for cadmium and 19.1 +6.3 ppm for lead. Comparing these data, for example, with a report on the metal concentrations in marine fish collected outside Victoria Harbour in the region offshore of the Pearl River estuary in 1987-1988 (Luk et al., 1990), the cadmium and lead concentrations in the rabbitfish in this study were significantly higher. Table 2 lists the metal concentrations in water samples collected from Victoria Harbour. The water samples collected from Kwun Tong were found to be heavily contaminated with copper and zinc, particularly in the suspended solids, in comparison with the other locations. Metal concentrations in water samples TABLE 1 Metal concentrations (ppm, dry weight) in tissues of rabbittish from Victoria Harbour. Copper
Zinc
Cadmium
Lead
5.7 4.0 3.6 0.6-73.5
66,6 31.8 53.9 14.9-347.6
3.3 1.1 3.0 0.6-7.1
19.1 6.3 17.0 6.0-40.3
15.6 4.0 16.4 2.9-26.0
165.7 56.5 144.0 39.9-913.2
18.0 4.6 17.9 6.0-33.6
94.6 22.7 91.9 40.8-199,5
26.6 15.9 19.8 0.3-135.4
192.9 105.0 139.1 15.6-973.4
3.9 1.1 3.8 1.4-6.8
26.8 10,2 23,3 7.0--98.1
170.6 71.8 130.8 71.8-493.4
13.9 3.7 13.2 1.7-25.4
83.1 18.6 83.0 25.5-147.1
Muscle (n = 51)
Mean SD Median Range Gills (n = 42)
Mean SD Median Range Viscera (n = 50)
Mean SD Median Range
Vertebrae (n--- 44)
Fig. 1 Sketch-map of Victoria Harbour in 1982 showing the sampling sites: Kwun Tong (KT), Central Pier (CP), Hung Horn (HH) and Wan Chai (WC).
278
Mean SD Median Range
10.4 3.7 11.1 1.9-21.6
Volume 31/Numbers 4--12/April-December1995 TABLE 2 Metal concentrations (ppb) in water samples from Victoria Harbour.*
Copper
Zinc
Cadmium
Lead
Filtrates CP/WC/HH (n = 38)
Mean SD Median Range
68.1 30.7 58.5 15-304
131.0 75.1 91 24--403
54.5 22.7 50.5 8-109
237.6 104.7 245 40--440
89.3 55.8 59 22-294
34.5 20.9 24 10-79
134.6 38.8 130 70-240
133.9 103.2 100.5 0--466
8.2 7.4 6 0--49
132.2 51.7 135 35-635
12.4 12.2 92.5 0-67
259.3 132.7 2025 15-515
Kwun Tong (n = 13)
Mean SD Median Range
1639 847.7 1521 158--3731
Suspended solids CP/WC/HH (n =42)
Mean SD Median Range
79.2 82.1 28.5 4.5-1526
Kwun Tong (n = 14)
Mean SD Median Range
12824 1049 I0 887.2 730.3 5852.5 709.3 2395-37010254.5-3157
*See Fig. 1 for locations.
collected from the other three locations in Victoria H a r b o u r were not significantly different from each other (Duncan's multiple range tests, p < 0.05); therefore, data are pooled together in Table 2. In general, the metal concentrations in the water samples were similar to or higher than (but still within the same order of magnitude as) those reported by Chan et al. (1974).
Discussion Luk e t al. (1990) investigated 15 species o f marine fish collected offshore from the estuarine region o f the Pearl River, directly west o f H o n g Kong. Metal concentrations were determined in the skin, flesh (muscle), bone, gills and viscera. Average values (ppm, dry weight) for metals in the muscle tissue were found to be 3.8 (range 1.6-7.1) for copper, 21.4 (range 6.8-30.9) for zinc, 0.08 (range 0.03-0.20) for cadmium and 0.7 (range 0.4--1.2) for lead. These values are of the same order o f magnitude as those reported for Atlantic cod (Gadus morhua) by HeUou et al. (1992), except for the lead concentrations. Lead concentrations in the muscle of the fish collected offshore from the Pearl River and in the rabbitfish in Victoria H a r b o u r are at least one order and 10 orders of magnitude higher, respectively, than those found in the Atlantic cod. Concentrations of all metals analysed in the tissues o f the rabbitfish from Victoria H a r b o u r were found to be higher than those reported for Atlantic cod muscle tissue. The levels o f trace metals in H o n g K o n g seafood from local harbours in 1976 and 1978 were investigated by Phillips et aL (1982). No significant metal contamination was detected in the fintish that were analysed, except in the case o f cadmium ( < 0 . 5 ppm, wet wt) and arsenic (range 0.3-21.1 ppm, wet wt). Comparing their
data with metal concentrations found in this study, copper, zinc, cadmium and lead concentrations in the rabbitfish tissues were found to be much higher. Burger & Gochfeld (1993) reported that the lead concentrations in the feathers o f egrets and herons found in Hong K o n g were among the highest in the world, and they believed that the high lead content was attributable to the use o f leaded gasoline. This explanation is also relevant to the present study, as the lead concentrations in the waters o f Victoria Harbour in 1983 were generally very high too (Table 2). These sample sites received sewage from seawall outfalls and urban runoff which might have contained a large amount of roadside dust heavily contaminated with lead (Lau & Wong, 1982). Fan (1989) reported that Jinzhou Bay in Bohai Sea, N o r t h China, was the most heavily polluted bay in China, with concentrations of mercury, cadmium, lead, zinc and copper at 1, 10, 10, 400 and 7 ppb, respectively. However, the metal concentrations in Victoria H a r b o u r in 1983 (Table 2) were found to be much higher than those reported by Fan (1989), except in the case of zinc, because a zinc smelter plant was one o f the main polluters in Jinzhou Bay. The metal concentrations detected in the water samples of the present study were much higher (except for zinc) than concentrations in the third-class sea area data investigated by Fan (1989). In conclusion, the rabbitfish collected from Victoria H a r b o u r in 1983 were found to be heavily contaminated with cadmium and lead. The heavily contaminated waters were thought to be directly responsible for the high metal concentrations in the rabbitfish. It would be important to examine recent metal concentrations in rabbitfish from Victoria H a r b o u r to see if the metal contamination has improved since 1983. The author would like to thank Prof. M. H. Wong for his generosity and support, and Mr K. S. Wong and Miss K. M. Siu for technical support. Allen, S. E., Grimshaw, H. M., Parkinson, J. A. & Quarmby, C. (1974). Chemical Analysis of Ecological Materials. Halsted Press, New York, USA. Burger, J. & Gochfdd, M. (1993). Heavy metal and selenium levels in feathers of young egrets and herons from Hong Kong and Szechuan, China. Arch. Environ. Contain. ToxicoL 25, 322-327. Chan, J. P., Cheung, M. T. & Li, F. P. (1974). Trace metals in Hong Kong waters. Mar. Pollut. Bull. 5, 171-174. Enviroumental Protection Department (1992). Environment Hong Kong 1992: a review of 1991. Government Printer, Hong Kong. Environmental Protection Department (1993). Environment Hong Kong 1993: a review of 1992. Government Printer, Hong Kong. Environmental Protection Department (1994). Environment Hong Kong 1994: a review of 1993. Government Printer, Hong Kong. Fan, Z. (1989). Tackling the most heavilypolluted bay in China. Mar. PoUut. Bull. 20, 362.
Hellou, J., Warren, W. G., Payne, J. F., Belkhode, S. & Lobel, P. (1992). Heavy metals and other dements in three tissues of cod, Gadus morhua, from the Northwest Atlantic. Mar. Pollut. Bull. 24, 452-458. Lau, W. M. & Wong, M. H. (1982). An ecological survey of lead contents in roadside dusts and soils in Hong Kong. Environ. Res. 28, 39-54. Little, T. M. & Hills, J. J. (1978). AgriculturalExperimentation: design and analysis. John Wiley, New York, USA. Luk, C. W., Lira, Y. T,, Yang, M. L., Ho, K. M. & Huang, X. P. (1990). Heavy metals in economically important marine fishes eoUected in Pearl River estuarine region. Mar. Environ. Sci. 9(2), 32-38 (in Chinese). 279
Marine Pollution Bulletin Morton, B. (1976). The Hong Kong sea-shore---an environment in crisis. Environ. Conserv. 3, 243-254. Morton, B. (1989). Pollution of the coastal waters of Hong Kong. Mar. Pollut. Bull. 20, 310--318. Phillips, D. J. H. (1979). The rock oyster Saccostrea glomerata as an indicator of trace metals in Hong Kong. Mar. Biol. 53, 353360. Phillips, D. J. H. (1985). Organochlorines and trace metals in greenlipped mussels Perna viridis from Hong Kong waters: a test of indicator ability. Mar. Ecol. Progr. Ser. 21, 251-258. Phillips, D. J. H. (1989). Trace metals and organoehiorines on the coastal waters of Hong Kong. Mar. Pollut. Bull. 20, 319327.
280
Phillips, D. J. H. & Rainbow, P. S. (1988). Barnacles and mussels as biomonitoring of trace elements: a comparative study. Mar. Ecol. Progr. Ser. 34, 261-266. Phillips, D. J. H. & Yim, W. W.-S. (1981). A comparative evaluation of oyster, mussels and sediments as indicators of trace metals in Hong Kong waters. Mar. Ecol. Progr. Set. 6, 285-293. Phillips, D. J. H., Thompson, G. B., Gabuji, K. M. & Ho, C. T. (1982). Trace elements of toxicological significance to man in Hong Kong seafood. Environ. Pollut. (B) 3, 27-45. Thompson, G. B. & Ho, J. (1981). Some effects of sewage discharge upon phytoplankton in Hong Kong. Mar. Pollut. Bull. 12, 168-173. Yim, W. W.-S. & Fung, K. W. (1981). Heavy metals in marine sediments of Hong Kong. Hong Kong Engng. 9(10), 33-39.
0025--326X(95)00136-0
Marine Pollution Bulletin, Vol. 31, Nos 4--12, pp. 277-280, 1995 Copyright © 1995 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0025-326X/95 $9.50 + 0.00
Concentrations of Copper, Zinc, Cadmium and Lead in Rabbitfish (Siganus oramin) Collected in Victoria Harbour, Hong Kong KING MING CHAN
Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong
The urban area of Hong Kong supports a population of about 4 million people, with an annual production of several hundred million tonnes of untreated domestic and industrial effluent. This causes significant marine pollution problems in Victoria Harbour. Moreover, urban runoff also brings pollutants to Victoria Harbour. This paper presents preliminary data on the concentrations of heavy metals from different parts of the rabbitfish (Siganus oramin) taken from Hung Horn, Wan Chai and the Central Ferry Pier, close to urban and sewage outfalls in Victoria Harbour, from June to September 1983. Metal concentrations in the seawaters and from the gills, viscera, vertebrae and muscle were determined by atomic absorption spectrophotometry. Concentrations of copper, zinc and lead in the muscle were found to be the lowest in the muscle as compared with other parts of the body (cadmium concentrations were similar in muscle and viscera), but concentrations were nevertheless still high (mean_+SD, dry weight): 5.7_4.0 ppm for copper, 66.6_+31.8 ppm for zinc, 3.3___1.1 ppm for cadmium and 19.1+__6.3 ppm for lead. Cadmium and lead concentrations in the rabbitfish samples of this study were significantly higher than those previously reported in fish from the nearby Pearl River estuary.
Two decades ago, seawater concentrations of cadmium, copper, zinc and lead in Victoria Harbour were 180 times, 2.5 times, 2 times and 160 times higher, respectively, than concentrations of these metals in the open ocean (Chan et al., 1974). Copper and zinc bioavailabilities in Victoria Harbour were also reported to be much higher than elsewhere in Hong Kong coastal waters, as reflected by the biomonitor, Saccostrea glomerata (phillips, 1979). This data, together with the report ofYim & Fung (1981) on metal concentrations in marine sediments of Hong Kong, indicated that the uncontrolled dumping of raw sewage, industrial effluent and urban runoff (via nullah drainage) from the urban areas of Hong Kong have caused significant marine pollution problems, which includes metal contamination in Victoria Harbour.
The urban area of Hong Kong supports a population of more than 4 million people, with approximately 300 million tonnes of untreated sewage, including domestic and industrial effluent, produced and discharged into Victoria Harbour annually (Morton, 1976, 1989; Thompson & Ho, 1981). Local hydrological flow was considered to be effective in diluting and flushing this sewage, but several dead-end areas in the harbour, such as the typhoon shelter Kai Tak Nullah which receives poor tidal flushing, were found to have deteriorated seriously (Environmental Protection Department, 1992, 1994). According to the data published in the recent annual reports (Environmental Protection Department, 1993, 1994), it appears that the situation has not improved since the 1970s, as reported by Morton (1976). Metal contamination of sediments in Victoria Harbour has also been monitored. The sediments in Victoria Harbour and the Tseun Wan area were found to be highly contaminated (200-400 ppm or more) with copper, zinc, lead, nickel and other metals (Yim & Fung, 1981; Environmental Protection Department, 1993, 1994). It is believed that film-processing factories, dyeing industries, ship leakage, paint, aerosol from vehicles (roadside dust), etc., are the sources of heavy metals in the urban runoff and sewage discharged into Victoria Harbour. To date, no studies have been published on the effects of metal pollution on fish populations in Victoria Harbour, although reports on the effects of metals on phytoplankton and on metal accumulation in rock oysters, barnacles and mussels have been published (Phillips & Yim, 1981; Thompson & Ho, 1981; Phillips, 1985, 1989; Phillips & Rainbow, 1988). Significantly large accumulations of copper, zinc and lead were found in the tissues of mussel and barnacles (as biomonitors) collected in Victoria Harbour (Phillips & Rainbow, 1988). The present investigation was carried out in 1983, and its aim was to investigate the metal concentrations in the tissues of the rabbitfish (Siganus oramin) collected from Victoria Harbour. Although submarine outfalls discharge sewage beyond the shoreline, seawall outfalls 277
Marine Pollution Bulletin
and nullah drainage outlets are still accessible in inshore marine organisms. In Victoria Harbour, several ferry piers with seawall outfalls and nullah drainage are often popular fishing spots for local people. One of the common species caught is the rabbitfish. This paper investigates the concentrations of copper, zinc, cadmium and lead in various parts of the rabbitfish and in the water samples collected in Victoria Harbour during the summer of 1983.
Results Table 1 shows the metal concentrations in various tissues of the rabbitfish collected from Victoria Harbour. The metal concentrations in the tissues of the rabbitfish collected from the three locations in Victoria Harbour (Fig. 1) were not significantly different (/7 < 0.05, data not shown) from each other as determined by Duncan's multiple range tests (Little & Hills, 1978), and therefore the data were pooled (Table
1). Methods Sampling sites were located on the shores of the central part of Victoria Harbour (Fig. 1). Water samples and fish were collected every 2 weeks, during the period from June to September 1983, at midtide between high and low tide, from Hung Hom, Wan Chai and Central Pier. Water samples were also collected at Kwun Tong Pier. The fish (four individuals, every 2 weeks from each site) and water samples were collected randomly from 3-15 m away from the seawall outfalls. The water samples were kept in acid-washed polyethylene bottles, acidified immediately after collection with the addition of 1% hydrochloric acid and were processed within 4 h. The fish were frozen at - 2 0 ° C until analysis (within 6 months). Analyses were performed in 1983-1984 in Dr M. H. Wong's laboratory, Biology Department, The Chinese University of Hong Kong. The rabbitfish collected ranged between 6.4 and 9.8 cm long (fork length) and between 6.8 and 16.6 g fresh wt. For tissue analyses, fish were dissected and divided into the gills, viscera, vertebrae and flesh (muscle), all of which were washed with distilled deionized water and dried on paper towels. Samples were dried to constant weight at 105°C and digested in a mixture (0.5:5:1) of sulphuric acid, nitric acid and perchloric acid (Allen et al., 1974), and the metal concentrations of the samples were determined by atomic absorption spectrophotometry using a Varian AA1475 spectrophotometer. For water analyses, samples of between 100 ml and 1 1 were treated to vacuum filtration (0.45 ~tm) to collect suspended solids for metal analyses. The acidified filtrate was also analysed for metal concentrations, by atomic absorption spectrometry using a Varian AA1475 spectrophotometer.
Duncan's multiple range tests were also performed to compare the data listed in Table 1. Lead and cadmium concentrations were found to be higher (p<0.01) in the gills and vertebrae, copper levels highest (p < 0.05) in the viscera and zinc levels lowest (p<0.05) in muscle as compared to the other parts of the body. The concentrations of copper, zinc and lead were found to be the lowest in the muscle as compared to the other parts of the body (cadmium concentrations were similar in muscle and viscera). In comparison with published local data (Phillips et al., 1982; Luk et al., 1990), however, metal concentrations were nevertheless high in the muscle (mean+SD, dry weight): 5.7+4.0 ppm for copper, 66.6-4-31.8 ppm for zinc, 3.3+ 1.1 ppm for cadmium and 19.1 +6.3 ppm for lead. Comparing these data, for example, with a report on the metal concentrations in marine fish collected outside Victoria Harbour in the region offshore of the Pearl River estuary in 1987-1988 (Luk et al., 1990), the cadmium and lead concentrations in the rabbitfish in this study were significantly higher. Table 2 lists the metal concentrations in water samples collected from Victoria Harbour. The water samples collected from Kwun Tong were found to be heavily contaminated with copper and zinc, particularly in the suspended solids, in comparison with the other locations. Metal concentrations in water samples TABLE 1 Metal concentrations (ppm, dry weight) in tissues of rabbittish from Victoria Harbour. Copper
Zinc
Cadmium
Lead
5.7 4.0 3.6 0.6-73.5
66,6 31.8 53.9 14.9-347.6
3.3 1.1 3.0 0.6-7.1
19.1 6.3 17.0 6.0-40.3
15.6 4.0 16.4 2.9-26.0
165.7 56.5 144.0 39.9-913.2
18.0 4.6 17.9 6.0-33.6
94.6 22.7 91.9 40.8-199,5
26.6 15.9 19.8 0.3-135.4
192.9 105.0 139.1 15.6-973.4
3.9 1.1 3.8 1.4-6.8
26.8 10,2 23,3 7.0--98.1
170.6 71.8 130.8 71.8-493.4
13.9 3.7 13.2 1.7-25.4
83.1 18.6 83.0 25.5-147.1
Muscle (n = 51)
Mean SD Median Range Gills (n = 42)
Mean SD Median Range Viscera (n = 50)
Mean SD Median Range
Vertebrae (n--- 44)
Fig. 1 Sketch-map of Victoria Harbour in 1982 showing the sampling sites: Kwun Tong (KT), Central Pier (CP), Hung Horn (HH) and Wan Chai (WC).
278
Mean SD Median Range
10.4 3.7 11.1 1.9-21.6
Volume 31/Numbers 4--12/April-December1995 TABLE 2 Metal concentrations (ppb) in water samples from Victoria Harbour.*
Copper
Zinc
Cadmium
Lead
Filtrates CP/WC/HH (n = 38)
Mean SD Median Range
68.1 30.7 58.5 15-304
131.0 75.1 91 24--403
54.5 22.7 50.5 8-109
237.6 104.7 245 40--440
89.3 55.8 59 22-294
34.5 20.9 24 10-79
134.6 38.8 130 70-240
133.9 103.2 100.5 0--466
8.2 7.4 6 0--49
132.2 51.7 135 35-635
12.4 12.2 92.5 0-67
259.3 132.7 2025 15-515
Kwun Tong (n = 13)
Mean SD Median Range
1639 847.7 1521 158--3731
Suspended solids CP/WC/HH (n =42)
Mean SD Median Range
79.2 82.1 28.5 4.5-1526
Kwun Tong (n = 14)
Mean SD Median Range
12824 1049 I0 887.2 730.3 5852.5 709.3 2395-37010254.5-3157
*See Fig. 1 for locations.
collected from the other three locations in Victoria H a r b o u r were not significantly different from each other (Duncan's multiple range tests, p < 0.05); therefore, data are pooled together in Table 2. In general, the metal concentrations in the water samples were similar to or higher than (but still within the same order of magnitude as) those reported by Chan et al. (1974).
Discussion Luk e t al. (1990) investigated 15 species o f marine fish collected offshore from the estuarine region o f the Pearl River, directly west o f H o n g Kong. Metal concentrations were determined in the skin, flesh (muscle), bone, gills and viscera. Average values (ppm, dry weight) for metals in the muscle tissue were found to be 3.8 (range 1.6-7.1) for copper, 21.4 (range 6.8-30.9) for zinc, 0.08 (range 0.03-0.20) for cadmium and 0.7 (range 0.4--1.2) for lead. These values are of the same order o f magnitude as those reported for Atlantic cod (Gadus morhua) by HeUou et al. (1992), except for the lead concentrations. Lead concentrations in the muscle of the fish collected offshore from the Pearl River and in the rabbitfish in Victoria H a r b o u r are at least one order and 10 orders of magnitude higher, respectively, than those found in the Atlantic cod. Concentrations of all metals analysed in the tissues o f the rabbitfish from Victoria H a r b o u r were found to be higher than those reported for Atlantic cod muscle tissue. The levels o f trace metals in H o n g K o n g seafood from local harbours in 1976 and 1978 were investigated by Phillips et aL (1982). No significant metal contamination was detected in the fintish that were analysed, except in the case o f cadmium ( < 0 . 5 ppm, wet wt) and arsenic (range 0.3-21.1 ppm, wet wt). Comparing their
data with metal concentrations found in this study, copper, zinc, cadmium and lead concentrations in the rabbitfish tissues were found to be much higher. Burger & Gochfeld (1993) reported that the lead concentrations in the feathers o f egrets and herons found in Hong K o n g were among the highest in the world, and they believed that the high lead content was attributable to the use o f leaded gasoline. This explanation is also relevant to the present study, as the lead concentrations in the waters o f Victoria Harbour in 1983 were generally very high too (Table 2). These sample sites received sewage from seawall outfalls and urban runoff which might have contained a large amount of roadside dust heavily contaminated with lead (Lau & Wong, 1982). Fan (1989) reported that Jinzhou Bay in Bohai Sea, N o r t h China, was the most heavily polluted bay in China, with concentrations of mercury, cadmium, lead, zinc and copper at 1, 10, 10, 400 and 7 ppb, respectively. However, the metal concentrations in Victoria H a r b o u r in 1983 (Table 2) were found to be much higher than those reported by Fan (1989), except in the case of zinc, because a zinc smelter plant was one o f the main polluters in Jinzhou Bay. The metal concentrations detected in the water samples of the present study were much higher (except for zinc) than concentrations in the third-class sea area data investigated by Fan (1989). In conclusion, the rabbitfish collected from Victoria H a r b o u r in 1983 were found to be heavily contaminated with cadmium and lead. The heavily contaminated waters were thought to be directly responsible for the high metal concentrations in the rabbitfish. It would be important to examine recent metal concentrations in rabbitfish from Victoria H a r b o u r to see if the metal contamination has improved since 1983. The author would like to thank Prof. M. H. Wong for his generosity and support, and Mr K. S. Wong and Miss K. M. Siu for technical support. Allen, S. E., Grimshaw, H. M., Parkinson, J. A. & Quarmby, C. (1974). Chemical Analysis of Ecological Materials. Halsted Press, New York, USA. Burger, J. & Gochfdd, M. (1993). Heavy metal and selenium levels in feathers of young egrets and herons from Hong Kong and Szechuan, China. Arch. Environ. Contain. ToxicoL 25, 322-327. Chan, J. P., Cheung, M. T. & Li, F. P. (1974). Trace metals in Hong Kong waters. Mar. Pollut. Bull. 5, 171-174. Enviroumental Protection Department (1992). Environment Hong Kong 1992: a review of 1991. Government Printer, Hong Kong. Environmental Protection Department (1993). Environment Hong Kong 1993: a review of 1992. Government Printer, Hong Kong. Environmental Protection Department (1994). Environment Hong Kong 1994: a review of 1993. Government Printer, Hong Kong. Fan, Z. (1989). Tackling the most heavilypolluted bay in China. Mar. PoUut. Bull. 20, 362.
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