Richard Cheung - Academia.edu (original) (raw)
Papers by Richard Cheung
Abstract The Gong system is a Web-based voice communication,system (http://gong.ust.hk). It allow... more Abstract The Gong system is a Web-based voice communication,system (http://gong.ust.hk). It allows people to communicate,in discussion groups using text and audio over the Internet. Major features of the system include voice indexing, selective word/phrase playback, voice speed-up/slow-down, real-time recordable voice chat and the support for multiple languages such as English, Chinese and Japanese. This paper discusses two different aspects of content development and management,using the Gong
2019 International Symposium on Educational Technology (ISET), 2019
City University of Hong Kong (CityU) was one of the pioneers in the applications of virtual reali... more City University of Hong Kong (CityU) was one of the pioneers in the applications of virtual reality (VR) technology in creative art, humanities and social science. Based on the learning design of a mobile app developed for a CityU MOOC, a smartphone-based solution was adopted to produce an immersive learning package for students to experience certain aspects of a field trip (or study tour). The adoption facilitated pre-class learning which was followed by in-class activities and assessment tasks to achieve the intended learning outcomes, in the context of the flipped classroom approach. Feedback from students indicated increased interest in learning within a virtual tour environment and the alignment of activities to learning outcomes was highly appreciated. Teachers in other local higher education institutions were also attracted by the pedagogical value of such VR field trip. Hence, the production workflow was documented in this paper to further promote the adoption of portable vi...
Agricultural Wastes, 1981
... Nature, 254, 594 5. 122 YH CHEUNG, MH WONG HENRY, DP, THOMSON, RUTH H., S1ZEMORE, DJ O'L... more ... Nature, 254, 594 5. 122 YH CHEUNG, MH WONG HENRY, DP, THOMSON, RUTH H., S1ZEMORE, DJ O'LEAVY, JA (1976). ... Utilization of dried poultry manure by growing chickens fed on a practicaldiet, Brit. Poultry Sci., 19, 137 42. ... SCHROEDER, GERALD L. (1977). ...
Agricultural Wastes, 1985
... When considering the types of heavy metals, it was found that Zn Cu Mn Pb. Of the four wastes... more ... When considering the types of heavy metals, it was found that Zn Cu Mn Pb. Of the four wastes, the highest heavy metal content was in shrimps fed on activated sludgegrown algae, followed by those fed on algae grown in digested sludge, chicken manure and pig manure. ...
Agricultural Wastes, 1986
ABSTRACT Our previous experiments showed that flowering Chinese cabbage (Brassica parachinensis) ... more ABSTRACT Our previous experiments showed that flowering Chinese cabbage (Brassica parachinensis) and Chinese radish (Rhaphanus sativus) var. longipinnatus grown in soil amended with sewage sludge and animal manure accumulated Pb, Cu, Zn and Mn. In this experiment, caterpillars of the common white butterfly (Pieris canidia) were fed with the waste-grown vegetables. Caterpillars fed with sewage sludge-grown vegetables had a lower body weight and a higher level of heavy metals than those fed with animal manure-grown vegetables (average fresh body weights of caterpillars fed with waste-grown leaves of Chinese radish were 75, 122, 186 and 196 mg for activated sludge, digested sludge, chicken manure and pig manure, respectively). Those fed with flowering Chinese cabbage accumulated a higher level of heavy metals than those fed with Chinese radish (Pb, 6·7-fold, Cu, 6·0-fold, Zn, 6·8-fold and Mn, 5·7-fold in treatments with activated sludge). As a whole, the accumulation of heavy metals in the caterpillars, in descending order, was from vegetables manured with activated sludge, digested sludge, chicken manure and pig manure.Caterpillars, even though ingesting an enormous amount of the leaves, accumulated a lower level of Pb, Cu and Zn than that found in the vegetables. The route of elimination was not verified but it was suggested that the egestion of faeces might play an important role.
Water Science and Technology, 1998
Water Science and Technology, 1995
Water Research, 1999
ÐA series of eight pilot-scale ponds (Au Tau pond system) were constructed at Au Tau Fisheries Oc... more ÐA series of eight pilot-scale ponds (Au Tau pond system) were constructed at Au Tau Fisheries Oce, Hong Kong Agriculture and Fisheries Department. Water from a polluted river (Kam Tin River) was pre-treated in the ®rst four ponds by providing sedimentation (S1, S2) and aeration (A1, A2). The euent from A2 was introduced into the latter four ponds (C1±C4) for polyculture of six species of freshwater ®sh (silver carp, big head, common carp, grass carp, tilapia and black bass) and supplementary ®sh feed (peanut cake) was provided. All ®sh (except grass carp) grew to marketable size within one year with a total yearly net yield of 5 t ha À1 yr À1. In addition to the supplied ®sh feed, ®sh also fed on the natural food developed in the ponds and ®sh growth (except common carp and tilapia) was found to be signi®cantly (p < 0.05) correlated with the concentrations of organic matter and nutrients in water. Biological oxygen demand, inorganic N and PO 4 3À were responsible for 60±80% variations of ®sh growth according to multiple regression analysis, which suggested that organic matter and nutrients in ponds aected ®sh growth through the food web developed in ponds. The N conversion to ®sh¯esh from total N input was not more than 3.5% which was below the range reported in other studies (5±25%). The total carbon contents in the sediments of ®sh ponds did not change signi®cantly (p> 0.05), but the signi®cant increase of N (p < 0.05) seemed to be derived from the input of ®sh feed and algal precipitation.
Toxicological & Environmental Chemistry, 1996
ABSTRACT Different dosages of ferrous chloride and ferric chloride were added to digestors separa... more ABSTRACT Different dosages of ferrous chloride and ferric chloride were added to digestors separately, and the volumes of methane and hydrogen sulphide contained in the digestor gas (biogas) were monitored. It was noted that the effects of adding of 16, 18 and 32 kg ferrous chloride/ tonne volatile solids, and 16 and 18 kg ferric chloride/tonne volatile solids were similarly effective in controlling the hydrogen sulphide levels.According to an average amount of undigested sludge (primary sludge mixed with surplus activated sludge) of 41 tonne volatile solids produced each day during the sewage treatment process in Shatin sewage treatment works, and the required dosage of 16 kg ferric chloride/ tonne volatile solids, the amount of iron salts required should be 656 kg/day or 3.3 mg/L for the actual application, based on an average sewage flow of 200,000 m/day.
Marine Pollution Bulletin, 1999
Marine Pollution Bulletin, 1995
Marine Pollution Bulletin, 2004
Hydrobiologia, 1989
... Page 2. 378 chinensis, B. parachinensis and Daucus carota (Wong & Lau, 1983), refuse comp... more ... Page 2. 378 chinensis, B. parachinensis and Daucus carota (Wong & Lau, 1983), refuse compost on B. para-chinensis (Wong, 1985) and effluent from a molasses distillery on Oryza sativa (Behera & Misra, 1982). In the era ...
Environmental Pollution, 1999
The present study aimed at studying the transplantation of oysters from a polluted site Lau Fau S... more The present study aimed at studying the transplantation of oysters from a polluted site Lau Fau Shan (existing oyster culture zone) in Deep Bay to two clean sites mariculture zones at Yung Shue O and Kat O. The hydrological data, growth of oyster shell length, mortality and metal contents in whole soft tissue were monitored from February 1993 to February 1994. The high growth phase (increase in shell length) and gametogenesis (decrease in dry weight of whole soft tissue) were noted in winter (with low temperature and high salinity), and slow growth phase and spawning in summer (with high temperature and low salinity). Sig-ni®cant reductions (p<0.05) of Cd, Cr and Pb concentrations (dry wt basis) in soft tissue of transplanted oysters were observed at Kat O by 29, 55 and 29%, respectively, and at Yung Shue O by 34, 44 and 34%, respectively, with respect to the baseline values for the ®rst batch of oysters and the concentrations in samples collected from Lau Fau Shan in the same months. Maximum reductions of total metal burden in whole soft tissue (mg per individual oyster) of the ®rst oyster batch were found for Cd, Cr, Pb and Sb to be 62, 49, 60 and 25%, respectively, at Kat O, and to be 56, 47, 32 and 49%, repectively, at Yung Shue O. For the second batch of oysters transplanted to Yung Shue O in July 1993, signi®cant reductions (p<0.05) of Cd concentration and total burden of Cd by 60 and 21%, respectively, were observed in February 1994. The high accumulated mortality and the signi®cant (p<0.05) lower growth rate of the tranplanted oysters illustrated that the best time for tranplantation of oysters should be between the end of gametogenesis and the start of spawning (i.e. January and February), and the oysters should not be kept for longer than 3 months at the transplantation sites.
Environmental Pollution, 1999
Samples of coastal sediment were collected from the southern (Victoria Harbour) and the western s... more Samples of coastal sediment were collected from the southern (Victoria Harbour) and the western side (Deep Bay) of Hong Kong to determine the existing or potential impacts of sediment-associated contaminants on the environment. The samples were analyzed for the total concentrations of Cd, Cr, Cu, Pb and Zn, ammonia-N, pH, and simultaneously extracted and soluble metals. Elutriate sediment toxicity tests (ESTT) were also conducted, using a microalgal¯agellate, Dunaliella tertiolecta. In the ®rst experiment, a total of six sediment samples were collected from the inner and outer areas of Deep Bay, inside Tuen Mun typhoon shelter, Rambler Channel, Tsuen Wan and the New Yau Ma Tei typhoon shelter. All the sediment elutriates had inhibitory eects on the growth of the microalgae. The lowest 48-h LC 50 was obtained in Tsuen Wan elutriate (42.6%). The results indicated that the percentage response of the microalgae was not directly correlated to heavy metal contents, but showed a positive correlation to the ammonia concentration. The calculated 48-h LC 50 of ammonia toxicity was 18.671.4 mg/l. In the second experiment, the toxicity of ammonia-N from a total of seven sediment samples (Kowloon Bay, Rambler Channel, Chai Wan, Sam Ka Tsuen, Causeway Bay, Aldrich Bay, Old Yau Ma Tei typhoon shelter) was determined. Air-stripped sediment elutriates reduced the total ammonia contents from 14.41±37.39 to 8.47±22.08 mg/l which signi®cantly reduced the toxic eect on the microalgae when compared with the non-air-stripped samples, suggesting that ammonia-N was one of the major toxicants in the elutriates. The 48-h LC 50 (NH 3) was calculated at 36.672.47 mg/l. These results suggested that a signi®cant component of sediment toxicity was a result of elevated ammonia, although there were elevated concentrations of potentially toxic heavy metals.
Environmental Pollution, 2005
A previously unknown s-triazine species present in commercially available Irgarol-1051, a booster... more A previously unknown s-triazine species present in commercially available Irgarol-1051, a booster biocide additive in copperbased antifouling paints for the replacement of organotin-based antifoulants, has been identified in the coastal aquatic environment. After careful isolation, purification and characterization by high resolution MS-MS and 1 H NMR, the molecular structure of that unknown species is found to be N,N#-di-tert-butyl-6-methylthiol-s-triazine-2,4-diamine (designated as M3). Levels of Irgarol-1051, its major degradation product (M1) and the newly identified M3 in the coastal waters of Hong Kong, one of the world's busiest ports located in the southern coast of China, were monitored by SPMEeGC-MS and SPMEeGC-FID. Water samples from five locations within Hong Kong waters were analysed and the levels of Irgarol-1051, M1 and M3 were found to be 0.1e1.6 mg l ÿ1 , 36.8e259.0 mg l ÿ1 and 0.03e0.39 mg l ÿ1 , respectively. Our results indicate that M3 is relatively stable against photo-and biodegradation and may pose considerable risk to primary producer communities in the coastal marine environment.
Environmental Pollution, 2000
Green-lipped mussels, Perna viridis, were collected from Kat O, Yim Tin Tsai, Ma Liu Shui and Tap... more Green-lipped mussels, Perna viridis, were collected from Kat O, Yim Tin Tsai, Ma Liu Shui and Tap Mun around Tolo Harbour and six local markets in Hong Kong (Aberdeen, Shau Kei Wan, Kowloon City, Mongkok, Yuen Long) and Shenzhen (Dongmun) between July 1994 and February 1995 and analysed for cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn). The metal concentrations of mussels collected from the study sites were Cd (0.45±1.44 mg/g), Cr (0.82±4.89 mg/g), Cu (6.02± 23.99 mg/g), Ni (3.25±6.87 mg/g), Pb (2.02±4.36 mg/g) and Zn (90±135 mg/g), while those from the markets were Cd (0.27±1.44 mg/g), Cr (1.09±3.30 mg/g), Cu (9.05±17.8 mg/g), Ni (2.44±5.25 mg/g), Pb (1.17±5 mg/g) and Zn (51±103 mg/g). The metal concentrations were below the maximum permissible levels set by the Hong Kong Government. In addition, seasonal variation of metal accumulation in mussels was investigated in Yim Tin Tsai and Ma Liu Shui and a reduction in the total heavy metal concentrations during winter was noted. The non-carcinogenic hazard index of mussels collected from Tolo Harbour and from Hong Kong markets was between 0.46 and 1.36 compared with those from Shenzhen markets (0.85±1.46), which indicated a low but possible risk in consuming the mussels.
Abstract The Gong system is a Web-based voice communication,system (http://gong.ust.hk). It allow... more Abstract The Gong system is a Web-based voice communication,system (http://gong.ust.hk). It allows people to communicate,in discussion groups using text and audio over the Internet. Major features of the system include voice indexing, selective word/phrase playback, voice speed-up/slow-down, real-time recordable voice chat and the support for multiple languages such as English, Chinese and Japanese. This paper discusses two different aspects of content development and management,using the Gong
2019 International Symposium on Educational Technology (ISET), 2019
City University of Hong Kong (CityU) was one of the pioneers in the applications of virtual reali... more City University of Hong Kong (CityU) was one of the pioneers in the applications of virtual reality (VR) technology in creative art, humanities and social science. Based on the learning design of a mobile app developed for a CityU MOOC, a smartphone-based solution was adopted to produce an immersive learning package for students to experience certain aspects of a field trip (or study tour). The adoption facilitated pre-class learning which was followed by in-class activities and assessment tasks to achieve the intended learning outcomes, in the context of the flipped classroom approach. Feedback from students indicated increased interest in learning within a virtual tour environment and the alignment of activities to learning outcomes was highly appreciated. Teachers in other local higher education institutions were also attracted by the pedagogical value of such VR field trip. Hence, the production workflow was documented in this paper to further promote the adoption of portable vi...
Agricultural Wastes, 1981
... Nature, 254, 594 5. 122 YH CHEUNG, MH WONG HENRY, DP, THOMSON, RUTH H., S1ZEMORE, DJ O'L... more ... Nature, 254, 594 5. 122 YH CHEUNG, MH WONG HENRY, DP, THOMSON, RUTH H., S1ZEMORE, DJ O'LEAVY, JA (1976). ... Utilization of dried poultry manure by growing chickens fed on a practicaldiet, Brit. Poultry Sci., 19, 137 42. ... SCHROEDER, GERALD L. (1977). ...
Agricultural Wastes, 1985
... When considering the types of heavy metals, it was found that Zn Cu Mn Pb. Of the four wastes... more ... When considering the types of heavy metals, it was found that Zn Cu Mn Pb. Of the four wastes, the highest heavy metal content was in shrimps fed on activated sludgegrown algae, followed by those fed on algae grown in digested sludge, chicken manure and pig manure. ...
Agricultural Wastes, 1986
ABSTRACT Our previous experiments showed that flowering Chinese cabbage (Brassica parachinensis) ... more ABSTRACT Our previous experiments showed that flowering Chinese cabbage (Brassica parachinensis) and Chinese radish (Rhaphanus sativus) var. longipinnatus grown in soil amended with sewage sludge and animal manure accumulated Pb, Cu, Zn and Mn. In this experiment, caterpillars of the common white butterfly (Pieris canidia) were fed with the waste-grown vegetables. Caterpillars fed with sewage sludge-grown vegetables had a lower body weight and a higher level of heavy metals than those fed with animal manure-grown vegetables (average fresh body weights of caterpillars fed with waste-grown leaves of Chinese radish were 75, 122, 186 and 196 mg for activated sludge, digested sludge, chicken manure and pig manure, respectively). Those fed with flowering Chinese cabbage accumulated a higher level of heavy metals than those fed with Chinese radish (Pb, 6·7-fold, Cu, 6·0-fold, Zn, 6·8-fold and Mn, 5·7-fold in treatments with activated sludge). As a whole, the accumulation of heavy metals in the caterpillars, in descending order, was from vegetables manured with activated sludge, digested sludge, chicken manure and pig manure.Caterpillars, even though ingesting an enormous amount of the leaves, accumulated a lower level of Pb, Cu and Zn than that found in the vegetables. The route of elimination was not verified but it was suggested that the egestion of faeces might play an important role.
Water Science and Technology, 1998
Water Science and Technology, 1995
Water Research, 1999
ÐA series of eight pilot-scale ponds (Au Tau pond system) were constructed at Au Tau Fisheries Oc... more ÐA series of eight pilot-scale ponds (Au Tau pond system) were constructed at Au Tau Fisheries Oce, Hong Kong Agriculture and Fisheries Department. Water from a polluted river (Kam Tin River) was pre-treated in the ®rst four ponds by providing sedimentation (S1, S2) and aeration (A1, A2). The euent from A2 was introduced into the latter four ponds (C1±C4) for polyculture of six species of freshwater ®sh (silver carp, big head, common carp, grass carp, tilapia and black bass) and supplementary ®sh feed (peanut cake) was provided. All ®sh (except grass carp) grew to marketable size within one year with a total yearly net yield of 5 t ha À1 yr À1. In addition to the supplied ®sh feed, ®sh also fed on the natural food developed in the ponds and ®sh growth (except common carp and tilapia) was found to be signi®cantly (p < 0.05) correlated with the concentrations of organic matter and nutrients in water. Biological oxygen demand, inorganic N and PO 4 3À were responsible for 60±80% variations of ®sh growth according to multiple regression analysis, which suggested that organic matter and nutrients in ponds aected ®sh growth through the food web developed in ponds. The N conversion to ®sh¯esh from total N input was not more than 3.5% which was below the range reported in other studies (5±25%). The total carbon contents in the sediments of ®sh ponds did not change signi®cantly (p> 0.05), but the signi®cant increase of N (p < 0.05) seemed to be derived from the input of ®sh feed and algal precipitation.
Toxicological & Environmental Chemistry, 1996
ABSTRACT Different dosages of ferrous chloride and ferric chloride were added to digestors separa... more ABSTRACT Different dosages of ferrous chloride and ferric chloride were added to digestors separately, and the volumes of methane and hydrogen sulphide contained in the digestor gas (biogas) were monitored. It was noted that the effects of adding of 16, 18 and 32 kg ferrous chloride/ tonne volatile solids, and 16 and 18 kg ferric chloride/tonne volatile solids were similarly effective in controlling the hydrogen sulphide levels.According to an average amount of undigested sludge (primary sludge mixed with surplus activated sludge) of 41 tonne volatile solids produced each day during the sewage treatment process in Shatin sewage treatment works, and the required dosage of 16 kg ferric chloride/ tonne volatile solids, the amount of iron salts required should be 656 kg/day or 3.3 mg/L for the actual application, based on an average sewage flow of 200,000 m/day.
Marine Pollution Bulletin, 1999
Marine Pollution Bulletin, 1995
Marine Pollution Bulletin, 2004
Hydrobiologia, 1989
... Page 2. 378 chinensis, B. parachinensis and Daucus carota (Wong & Lau, 1983), refuse comp... more ... Page 2. 378 chinensis, B. parachinensis and Daucus carota (Wong & Lau, 1983), refuse compost on B. para-chinensis (Wong, 1985) and effluent from a molasses distillery on Oryza sativa (Behera & Misra, 1982). In the era ...
Environmental Pollution, 1999
The present study aimed at studying the transplantation of oysters from a polluted site Lau Fau S... more The present study aimed at studying the transplantation of oysters from a polluted site Lau Fau Shan (existing oyster culture zone) in Deep Bay to two clean sites mariculture zones at Yung Shue O and Kat O. The hydrological data, growth of oyster shell length, mortality and metal contents in whole soft tissue were monitored from February 1993 to February 1994. The high growth phase (increase in shell length) and gametogenesis (decrease in dry weight of whole soft tissue) were noted in winter (with low temperature and high salinity), and slow growth phase and spawning in summer (with high temperature and low salinity). Sig-ni®cant reductions (p<0.05) of Cd, Cr and Pb concentrations (dry wt basis) in soft tissue of transplanted oysters were observed at Kat O by 29, 55 and 29%, respectively, and at Yung Shue O by 34, 44 and 34%, respectively, with respect to the baseline values for the ®rst batch of oysters and the concentrations in samples collected from Lau Fau Shan in the same months. Maximum reductions of total metal burden in whole soft tissue (mg per individual oyster) of the ®rst oyster batch were found for Cd, Cr, Pb and Sb to be 62, 49, 60 and 25%, respectively, at Kat O, and to be 56, 47, 32 and 49%, repectively, at Yung Shue O. For the second batch of oysters transplanted to Yung Shue O in July 1993, signi®cant reductions (p<0.05) of Cd concentration and total burden of Cd by 60 and 21%, respectively, were observed in February 1994. The high accumulated mortality and the signi®cant (p<0.05) lower growth rate of the tranplanted oysters illustrated that the best time for tranplantation of oysters should be between the end of gametogenesis and the start of spawning (i.e. January and February), and the oysters should not be kept for longer than 3 months at the transplantation sites.
Environmental Pollution, 1999
Samples of coastal sediment were collected from the southern (Victoria Harbour) and the western s... more Samples of coastal sediment were collected from the southern (Victoria Harbour) and the western side (Deep Bay) of Hong Kong to determine the existing or potential impacts of sediment-associated contaminants on the environment. The samples were analyzed for the total concentrations of Cd, Cr, Cu, Pb and Zn, ammonia-N, pH, and simultaneously extracted and soluble metals. Elutriate sediment toxicity tests (ESTT) were also conducted, using a microalgal¯agellate, Dunaliella tertiolecta. In the ®rst experiment, a total of six sediment samples were collected from the inner and outer areas of Deep Bay, inside Tuen Mun typhoon shelter, Rambler Channel, Tsuen Wan and the New Yau Ma Tei typhoon shelter. All the sediment elutriates had inhibitory eects on the growth of the microalgae. The lowest 48-h LC 50 was obtained in Tsuen Wan elutriate (42.6%). The results indicated that the percentage response of the microalgae was not directly correlated to heavy metal contents, but showed a positive correlation to the ammonia concentration. The calculated 48-h LC 50 of ammonia toxicity was 18.671.4 mg/l. In the second experiment, the toxicity of ammonia-N from a total of seven sediment samples (Kowloon Bay, Rambler Channel, Chai Wan, Sam Ka Tsuen, Causeway Bay, Aldrich Bay, Old Yau Ma Tei typhoon shelter) was determined. Air-stripped sediment elutriates reduced the total ammonia contents from 14.41±37.39 to 8.47±22.08 mg/l which signi®cantly reduced the toxic eect on the microalgae when compared with the non-air-stripped samples, suggesting that ammonia-N was one of the major toxicants in the elutriates. The 48-h LC 50 (NH 3) was calculated at 36.672.47 mg/l. These results suggested that a signi®cant component of sediment toxicity was a result of elevated ammonia, although there were elevated concentrations of potentially toxic heavy metals.
Environmental Pollution, 2005
A previously unknown s-triazine species present in commercially available Irgarol-1051, a booster... more A previously unknown s-triazine species present in commercially available Irgarol-1051, a booster biocide additive in copperbased antifouling paints for the replacement of organotin-based antifoulants, has been identified in the coastal aquatic environment. After careful isolation, purification and characterization by high resolution MS-MS and 1 H NMR, the molecular structure of that unknown species is found to be N,N#-di-tert-butyl-6-methylthiol-s-triazine-2,4-diamine (designated as M3). Levels of Irgarol-1051, its major degradation product (M1) and the newly identified M3 in the coastal waters of Hong Kong, one of the world's busiest ports located in the southern coast of China, were monitored by SPMEeGC-MS and SPMEeGC-FID. Water samples from five locations within Hong Kong waters were analysed and the levels of Irgarol-1051, M1 and M3 were found to be 0.1e1.6 mg l ÿ1 , 36.8e259.0 mg l ÿ1 and 0.03e0.39 mg l ÿ1 , respectively. Our results indicate that M3 is relatively stable against photo-and biodegradation and may pose considerable risk to primary producer communities in the coastal marine environment.
Environmental Pollution, 2000
Green-lipped mussels, Perna viridis, were collected from Kat O, Yim Tin Tsai, Ma Liu Shui and Tap... more Green-lipped mussels, Perna viridis, were collected from Kat O, Yim Tin Tsai, Ma Liu Shui and Tap Mun around Tolo Harbour and six local markets in Hong Kong (Aberdeen, Shau Kei Wan, Kowloon City, Mongkok, Yuen Long) and Shenzhen (Dongmun) between July 1994 and February 1995 and analysed for cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn). The metal concentrations of mussels collected from the study sites were Cd (0.45±1.44 mg/g), Cr (0.82±4.89 mg/g), Cu (6.02± 23.99 mg/g), Ni (3.25±6.87 mg/g), Pb (2.02±4.36 mg/g) and Zn (90±135 mg/g), while those from the markets were Cd (0.27±1.44 mg/g), Cr (1.09±3.30 mg/g), Cu (9.05±17.8 mg/g), Ni (2.44±5.25 mg/g), Pb (1.17±5 mg/g) and Zn (51±103 mg/g). The metal concentrations were below the maximum permissible levels set by the Hong Kong Government. In addition, seasonal variation of metal accumulation in mussels was investigated in Yim Tin Tsai and Ma Liu Shui and a reduction in the total heavy metal concentrations during winter was noted. The non-carcinogenic hazard index of mussels collected from Tolo Harbour and from Hong Kong markets was between 0.46 and 1.36 compared with those from Shenzhen markets (0.85±1.46), which indicated a low but possible risk in consuming the mussels.