In the region of Bransfield Strait and southern part of Drake Passage the highest amounts of chlorinated hydrocarbons (CHs — compounds of the DDT group, HCH isomers and PCBs) were found in the samples taken at the sampling station where the CHs bottom deposits were released to the upper layers due to the special hydrological situation at this station. Increased amounts of CHs were observed also in phytoplankton sampled close to the melting ice of glacier origin which was considered as a source of pollution. However, phytoplankton sampled from the waters covered with pack-ice exhibited the lowest rate of CHs accumulation. Slightly elevated CHs accumulation was found in sea ice diatoms. All the samples exhibited elevated amount of polichlorinated biphenyls, markedly higher than that of chloroorganic insecticides.
In Antarctic summer 1983/1984 samples of planktonie and attached diatoms were collected in the Admiralty Bay (King George Island, South Shetland Islands) as well as samples of planktonie diatoms in the region of South Orkneys, Drake Passage and Bransfield Strait (BIOMASS-SIBEX Project). Using gas chromatography residues of chloroorganic pesticides, namely the compounds of the DDT group and HCH isomers were determined. It was found that the highest values of the content of these compounds occurred in attached diatoms coming from areas continuously washed with water from the melting glacier, in planktonie diatoms from the samples of the Admiralty Bay and from strongly glaciated regions. A hypothesis was put forward that along with the direct atmospheric transport the release of the deposits of these compounds from ice and glaciers during their melting is an additional source of input of chloroorganic biocides into Antarctic waters. Diatoms are good indicators of this process.
Influence exerted by various concentrations (0.01 to 50 ppm) of some chlorinated hydrocarbons (Aroclor 1254, Aroclor 1242, pp'DDE, pp'DDT and Lindane (ɣ НСН)) upon the photosynthetic assimilation of 14C02 in Antarctic marine diatom assemblage dominated by Corethron criophilum and some species of Nitzschia (Fragilariopsis group) has been investigated. The photosynthesis was fully inhibited by Lindane (ɣ HCH) in all applied concentrations To smaller extent the photosynthetic process was inhibited in turn by Aroclor 1242, pp'DDE and pp'DDT successively. Aroclor 1254 proved to be the least toxic. The possibility of the decrease of the primary production of the Antarctic diatoms caused by the chlorinated hydrocarbons was discussed.
Experiments have been carried out on the influence exerted by Aroclor 1254 upon the photosynthetic production of organic 14C by an assemblage of marine Antarctic diatoms (Thalassiosira sp. 48%, Nitzschia sp. 21%, Chaetoceros sp. 15% and Corethron iriophilum 10%). Samples of various numbers of cells per cm3 of water have been used. Incorporation of 14C02 by the diatoms proved to be proportional to the increased number of cells in the sample only at the lowest levels of concentration in per cm3. Further increase of the level of 14C in diatoms has not been found as number of cells in the sample kept growing. Calculation of brutto photosynthesis has indicated that low concentration of Aroclor 1254 (0,01 to 1 ppm) may stimulate the photosynthetic incorporation of carbon, yet the photosynthetic release of carbon from cells within the photorespiratory process is stimulated to a higher degree. High concentration of Aroclor (1 to 50 ppm) inhibit the brutto assimilation, yet the release of carbon during the photorespiratory process is inhibited to a higher degree. A hypothesis is being considered implying that the relation between the intensity of photosynthesis and intensity of photorespiration may vary according to the rate of concentration of Aroclor.
The influence of Lindane on net phytoplankton (mainly diatoms) in samples of waters from the Antarctic was investigated for 24 hours from the introduction of ɣ HCH 0,02 and 2 ppm into the environment. Changes in intensity of 14C incorporation in the light and in rate of release of 14C by the cells in the dark during consecutive light/dark periods were measured. The effect of two different Lindane concentrations in diatoms occurred 16 hours after introduction of the compound into the environment and was independent of concentration. The effect was manifested by delayed induction of photosynthesis following the dark period and also by changes in dynamic equilibrium between carbon assimilation and dissimilation. The presence of Lindane clearly stimulated 14C incorporation in the light and also enhanced the participation of 14C incorporation in overall CO2 exchange in the dark.
Contents of PCBs was investigated using the gas chromatography method in the tissue of four Antarctic migratory birds: Oceanites oceanicus, Larus dominicanus, Catharacta skua and Sterna vittata, and the three penguin species: Pvgoscelis adeliae, P. papua and P. antarctica. Samples were collected at King George Island in February 1978 and, for comparison, in March 1983. The highest PCBs content was recorded in the adipose tissue of O. oceanicus and C. skua (15.7 and 1.2 ppm). Differences in the content of these compounds in the tissue of various penguin species in 1978 was observed. The mean cumulation level of PCBs in the adipose tissue of penguins was higher in 1983 than in 1978. Differences in the level of PCBs contents in the tissue of migratory birds were related to their winter migrations to areas polluted to various degress with PCBs remains. A tendency to the increase of the contamination of penguin tissues with PCBs was observed. This tendency was related to the increase of vhe pollution of the Antarctic environment with these compounds.
In 1979- 1981 at the King George Island samples of adipose tissue of 5 pinniped species (L. carcinophagus, L. weddelli, H. leptonyx, M. leonina and A. gazella) were collected and the contents of chlorinated hydrocarbons (CHs) were determined with the gas chromatography method. The highest values were recorded in the leopard seal (432.3 -614.7 ppb DDT), the second highest values in the mature elephant seal (73.4 ppb DDT) and the third in the Weddell seal (54.4 — 69.1 ppb DDT). In the Weddell seal the highest level of HCH content (23.3 — 32.1 ppb) was recorded. A decrease in the content of pp'DDE in the adipose tissue of crabeater seal in successive years was recorded, the values being 36.8 ppb in 1979, 24.4 ppb in 1980 and 15.3 ppb in 1981, as well as an increase in the concentration of HCH (15.3 ppb in 1980 and 27.4 ppb in 1981). The contents of CHs in the adipose tissue of Antarctic pinnipeds are 100—1000 times lower than those in the Arctic seals.