Ecotoxicology of stable pollutants in Antarctic marine ecosystems: mercury and organochlorines
Joiris, C.; Holsbeek, L. (1993). Ecotoxicology of stable pollutants in Antarctic marine ecosystems: mercury and organochlorines, in: Caschetto, S. (Ed.) Belgian scientific research programme on Antarctica: scientific results of phase II (10/1988-05/1992): 1. Plankton ecology and marine biogeochemistry. pp. II/07/A/1-33 In: Caschetto, S. (Ed.) (1993). Belgian scientific research programme on Antarctica: scientific results of phase II (10/1988-05/1992): 1. Plankton ecology and marine biogeochemistry. Belgian scientific research programme on Antarctica. Belgian Science Policy Office: Brussel. 295 pp., more In: Belgian scientific research programme on Antarctica. Belgian Science Policy Office: Brussel. , more |
| Abstract | The ecotoxicological study of marine ecosystems concerns the determination of the concentration and transfer mechanisms of stable pollutants in the main biological compartments. In the Antarctic, data were gathered on heavy metals: total and organic (methyl) mercury, and organochlorines: pesticides and PCBs. Contamination of phytoplankton (suspended particular matter) is high when expressed on fresh (or dry) weight basis and reaches values as high as in the heavily polluted North Sea. In order to determine and compare the contamination at the ecosystem level, it is however necessary to express the same data in other units, namely per volume of sea water, since particulate matter is directly contaminated trom the water through adsorption, absorption and partition on the lipids. It appears then that the Antarctic marine systems are about six times less contaminated than the North Sea. The high concentrations per weight unit are resulting from much lower biomasses in the Antarctic: the total load of basically water insoluble residues is almost enterily distributed on less particles, leading to a higher load per particle. This relatively high contamination by mercury and organochlorines is also more recent than in Western Europe and North America, where their utilization was controlled or banned trom the seventies on, while they are still used on a large scale in southern developping countries. A high DDT to DDE ratio provides a typical example of this phenomenon. This situation: relatively low ecosystem load, high concentration on the particulate matter, allows to detect the main transfer mechanisms of the contaminants to the higher trophic levels: if the higher trophic levels, e.g. fish, were mainly indirectly contaminated through their food, high levels of mercury and organochlorines were to be expected. The obtained results show, on the contrary, that contamination levels are much lower than in the North Sea. This clearly shows the importance of direct contamination trom the water to the fish, a confirmation of experimental data. Seabirds being indirectly contaminated from this fish, also present low levels of pollutants, compared with North Sea data. |
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