Marine Pollution Bulletin
Edited byE. I. Hamilton Marine Ibllution Ihdletin, Vol. 18, N~, 10, pp. 5 6 4 - 5 6 6 , 1987, Printed in Great Britain.
The objective of BASELINE is to publish short communications for the concentration and distribution of elements and compounds in the marine environment. Only those papers which clearly identify the quality of the data will be considered for publication. Contributors to Baseline should refer to 'Baseline--A Record of Contamination Levels' (Mar. Pollut. Bull. 13,217-218).
Metals in 19 Intertidal Macroalgae in Hong Kong Waters Levels of metals in marine animals in Hong Kong have been extensively studied (e.g. Phillips et al., 1982), but only limited information is available for the three macroalgae Chaetomorpha brachygona, Enteromorpha crinita (Wong et al., 1979) and Ulva lactuca (Ho, 1981). This paper reports on the levels of seven metals in 19 species of macroalgae collected from 17 intertidal sites around the Island of Hong Kong. As shown in Fig. 1, Sites 1-10 are in the rural south and southeastern parts of Hong Kong where the coastal waters are relatively clean. The northern part of the Island, in which the remaining sites are situated, and Kowloon are highly urbanized and border on Victoria Harbour which receives untreated domestic sewage and industrial effluents from a population of > 3.5 million. About 0.2 to 0.5 kg fresh weight of alga was harvested for each sample during low tide; 90 algal samples were taken. After collection, the samples were dried for 24-48 h at 105°C and then ground. Duplicated subsamptes each weighing about 1 g dry wt were acid-digested (Ho, 1984). Reagent blanks were also
Fig. I Map of Hong Kong showing the locations of the sampling sites (numbered) and the sewage outfalls (arrowed).
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prepared. The concentration of metals in the subsamples was determined by atomic absorption spectrometry (Instrumentation Laboratory 651, with background correction and actylene as fuel) and data are expressed as gg metal g-~ dry wt. No detectable ( < 0.01 gg m1-1) amounts of Mn, Ni, Cu, Cd, and Pb were found in the reagent blanks. Occasional contamination of Fe and Zn was detected which at most contributed to < 3% of the metals in the algae. The mean coefficients of variation for Mn, Fe, Ni, Cu, Zn, Cd, and Pb were respectively 2.1, 2.8, 4.4, 2.4, 2.4, 4.8, and 7.6%. Table 1 presents the mean and range values of the seven metals for each of the 19 species of algae studies. In most cases metal levels in an alga from more than one site were pooled to give a single mean and ranged values. Generally the order of metal abundance in the algae was Fe > Mn, Zn > Cu, Ni, Pb > Cd. An alga with a high level of Fe usually had a relatively high level of Mn and vice versa (Table 1). The same applies to the variability of these two metals within an alga. Dermonema frappieri was rather exceptional as it consistently had higher levels of Mn than Fe. Enterornorpha flexuosa, Colpomenia sinuosa and Ectocarpus siliculosus accumulated high levels of Fe. Conversely Hizikia fusiforme contained a relatively low level of Fe. The levels of Ni and Cu in the algae were often < 10 p.g g-t. Both Ectocarpus siliculosus and Dermonerna frappieri apparently took up these two metals to a greater extent than the other algae in the rural sites (Table 1). With the exceptions of Rhizoclonium and Dermonema the rural algae normally contained between 10 and 100 gg g-t of Zn. Relatively low levels of - 1 gg g-~ or less of Cd were found in most of the algae. However, the two red algae Corallina pilulifera and Dermonema frappieri had relatively high mean Cd values of 2.5 and 1.8 gg g-t respectively. Algae from the rural sites had -< 15 gg g-I of Pb in most cases but the concentration range of the metal for each alga might be considerable as in Chaetornorpha antennina and Scytosiphon lomentaria. When compared with the same algae in the rural sites, the two species of Enteromorpha in the urban areas, namely, E. compressa and E. ,flexuosa accumulated some 4 to 10 times more Mn, Fe, Cu, Zn, and Pb. Similarly Gymnogongrus flabelliformis from site 11 had significantly higher levels of Mn, Fe, and Pb than those found in the rural sites. Although Caulacanthus okamurai was only taken from the urban area, and hence no data from the rural sites were available for comparison, high contents of Mn, Fe, Cu, Zn, and Pb were found. Therefore the waters in Victoria Harbour contain higher levels of these metals than those in the southern part of the Island. Higher seawater metal levels led to a greater bioaccumulation of these metals in the algae.
Volume 18/Number 10/October 1987
TABLE 1 Mean and range values (p.g g-~ dry wt) of the metals in the algae. Site
2, 5, 6
Rhi, oclonium riparium
4, 5, 7-10
Ecto ca rpus si licu Iosus
1, 3, 5, 7-10
1-3, 5, 7
l 5.4 9.0-25.7
Phaeophyta Colpornenia sinuosa
lshigefoliacea lshige okamurai
Rhodophyta Caulacanthus okamurai Corallina pihdifem Derrn on em a frappieri
The major source of these metals in the Harbour waters came from the continuous discharge of vast quantities of domestic and industrial effluents through the many major and numerous minor outfalls and contaminated stormwater drains. Indeed Chan et al. (1974) found high metal contents, including Fe, Cu, Zn, and Pb in shoreline waters near the main outfalls in the Harbour. The levels of Ni and Cd in the algae from the urban sites were not much higher than those in the corresponding algae from the rural sites. This indicated that either only limited contamination of these metals occurred in the urban sites relative to the rural ones, or
that the elements were not very bioavailable and hence no appreciable bioaccumulation took place.
Y.B. HO Department of Botany, University of Hong Kong, Pokfulam Road, Hong Kong Chan, J. P., Cheung, M. T. & Li, F. P. (1974). Trace metals in Hong Kong waters. Mar Polha. Bull. 5 , 1 7 1 - t 7 4 . Ho, Y. B. (1981). Mineral element content in Ulva lactuca L. with reference to eutrophication in Hong Kong coastal waters. Hydrobiologia 77, 43-47.
Marine Pollution Bulletin Ho, Y. B. (1984). Zn and Cu concentrations in Ascophyllurn nodosum and Fucus vesiculosus (Phaeophyta, Fucales) after transplantation to an estuary contaminated with mine wastes. Conserv. Recycl. 7, 329337. Phillips, D. J. H., Thompson, G. B., Gabuji, K. M. & Ho, C. T. (1982).
Marine Pollution Bulletin, Vol, 18, No. 10, pp. 5 6 6 - 5 6 7 , 1987. Printed in Great Britain.
An occasional series on the current activities of the Joint Group of Experts on the Scientific Aspects of Marine Pollution.
Outcome of GESAMP XVII GESAMP, which is the IMO, FAO, UNESCO, WMO, WHO, LAEA, UN, and UNEP Joint Group of Experts on the Scientific Aspects of Marine Pollution, held its seventeenth session at the Headquarters of FAO, Rome, from 30 March to 3 April 1987. This group, upon request by its sponsoring agencies, provides advice on marine pollution issues particularly in those cases where a multidisciplinary approach is needed which goes beyond the expertise of the specialized agencies and United Nations bodies. In light of the rather different scopes of the sponsoring agencies, the topics considered by the group cover a wide range of items in the field of prevention and control of marine pollution. These include the review of substances which might pose harmful effects to the marine environment (under discussion are carcinogenic substances and nutrients), the evaluation of hazards of harmful substances carried by ships (chemicals in bulk or transported as packaged goods), the interchange of pollutants between the atmosphere and the oceans, the riverine inputs of contaminants into the sea, the establishment of global ocean monitoring systems, the evaluation of coastal modelling relevant to inputs into the sea of wastes discharged from land or dumped in shelf areas (in particular low-level radioactive wastes), the long-term ecological consequences of low-level contamination of the marine environment. Last but not least, the group recently began an attempt at evaluating the state of the marine environment as a whole. Two new fields of activity relating to economic aspects of marine pollution and to the use of the 'collective dose' approach (so far used by ICRP in radiological protection) for examining effects on human health of anthropogenic inputs to the marine environment are under consideration, i.e. GESAMP is discussing whether these topics should be included in its future work programme. GESAMP, since its establishment in 1969, has so far published thirty reports and studies on scientific aspects of marine pollution, and these have been widely circulated within the scientific community. The report of its recently held seventeenth session is being published by FAO as No. 31 of the GESAMP reports 566
Trace metals of toxicological significance to man in Hong Kong seafood. Environ. Pollut. (Ser. B) 3, 27-45. Wong, M. H., Chan, K. Y., Kwan, S. H. & Mo, C. E (1979). Metal contents of the two marine algae found on iron ore tailings. Mar. Pollut. Bull. 10, 56-59.
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and studies series. A study on land-sea boundary flux will be published in the near future by UNESCO as GESAMP Reports and Studies No. 32. All GESAMP publications can be made available free of charge through one of the sponsoring agencies or by the Administrative Secretary of GESAMP (Director, Marine Environment Division, International Maritime Organization, 4 Albert Embankment, London SE1 7SR, UK). At the seventeenth session of GESAMP discussions mainly focused on two subject items: 1. Integrated Global Ocean Monitoring, and 2. the State of the Marine Environment. With regard to the Integrated Global Ocean Monitoring, GESAMP could not wholeheartedly support proposals for the development of this concept as prepared by a working group. The working group, comprised of GESAMP members and outside experts, had made an attempt to define a scientific rationale, as well as a justification for an integrated global ocean monitoring concept. However GESAMP felt that for the implementation of the plans developed by the working group an over-optimistic approach had been taken with regard to time-frames and the availability of monitoring techniques and methods. It was further pointed out that quite a number of existing international scientific programmes of regional and global scope had not sufficiently been taken into account. On the other hand a number of GESAMP experts, as well as representatives from several of the sponsoring agencies, were satisfied with the work accomplished. It was one of the cases where no consensus could be reached by GESAMP, basically due to the diversity of views of the scientists concerned, and therefore the report will not be published in the GESAMP reports and studies series. In this regard it was noted that other attempts made by GESAMP many years ago on the development of global ocean monitoring systems had likewise been a matter of controversy. The UNEP Technical Secretary of GESAMP, representing the organization which had provided considerable financial funding to the work, indicated that a study reflecting the various attempts made by GESAMP on global ocean monitoring would be prepared for publication in UNEP's Regional Seas Reports and Studies; this would include the ideas and concepts of the report of the working group on integrated global ocean monitoring. The other item considered by GESAMP resulting in some heated debate was the very ambitious undertaking