Collected reprints: Abstract 3746
Collected reprints
Abstract
Persoone, G.; Van Steertegem, M. (1987). The influence of temperature and salinity on the sensitivity of Artemia nauplii to chemical compounds. Artemia Research and its Applications 1:
The toxicity of chemicals to aquatic organisms is mostly determined in a set of experimental conditions which are close to optimal for the test species. Because in nature organisms have to cope with fluctuating environmental conditions which can range during the course of the year from optimal to suboptimal, up to the limits of the tolerance range, the conditions under which routine bioassays are normally performed do, however, not reflect the large range of situations occurring in the field. Considering the scarcity of information on the effect of fluctuating environmental conditions on the sensitivity of test species to toxicants, a comparative laboratory study has been undertaken to determine the combined influence of environmental variables on the sensitivity of three aquatic invertebrates : the brackish water rotifer Brachionus plicatilis, the freshwater crustacean Daphnia magna, and the marine crustacean Artemia.
This study reports on the combined effects of two important abiotic variables, namely temperature and salinity, on the sensitivity of Artemia nauplii for two chemical compounds : potassium dichromate and sodium laurylsulphate. LC50 24h have been determined, using the standardized ARC-test in a factorial design with temperatures ranging from 10 to 30°C in combination with salinities ranging from 5 to 50 promille. The results reveal that whereas the LC50 in standard conditions is approximately 22 mg/l for both chemicals, the LC50's ranged from 9 up to 291 mg/l for potassium dichromate and from 7 up to 154 mg/l for sodium laurylsulphate in the various combinations of the factorial experiment. Consequently, changes in environmental conditions thus influenced the outcome of the test by increasing the sensitivity of the test organism by a factor of 2.5 and 3 respectively, or decreasing it by a factor 7 up to 13, in comparison to the so-called "standard" conditions. Furthermore, comparing the results with analogous experiments carried out with the two other test species named above, it appeared that the pattern and the magnitude of the variation in toxicity resulting from different environmental conditions is chemical as well as species dependent.
This study thus clearly demonstrates once more the necessity to take environmental factors into consideration for the predictive determination of the hazard of manmade chemicals.
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