SECTION 11 



THE PREDICTION OF THE EFFECTS OF POLLUTANTS ON AQUATIC ORGANISMS 

 BASED ON THE DATA OF ACUTE TOXICITY EXPERIMENTS 



O.F. Filenko and E.F. Isakoval 



The increasing number of pollutants requires acceleration of the ability 

 to assess their toxicity, and to determine acceptable levels in the environ- 

 ment. These needs, coupled with a reduction of analytic costs, require a 

 reduction in the length of experimental effort, and, at the same time, an 

 increase in the reliability of the response. 



To accelerate capabilities of assessment of toxicity, attempts were made 

 to connect the biological activity of compounds with their physico-chemical 

 properties. The correlation of toxicity of individual compounds with ap- 

 proximately 40 different physico-chemical properties were investigated 

 (Filov and Liublina 1965). Naturally, a high correlation of these data for 

 one organism is not sufficiently reliable for a group of species. It is 

 known that reactions of different organisms, and occasionally even one or- 

 ganism, to the same toxin are different under altered conditions. In such 

 cases, toxicity can differ by many orders of magnitude. 



Another direction in the search has been an attempt to find the specific 

 and especially sensitive reactions of organisms to the action of a given 

 pollutant. These attempts have mostly failed. The sensitive and specific 

 index for poisoning by land, an increasing level of 8-amino levulic acid in 

 blood and urea, proved to be less sensitive than in the case of poisoning by 

 mercury (Jackim 1973). 



Usually such biophysical, biochemical, and physiological indices assist 

 in identifying harmful effects after they have produced irreversible changes 

 in the organism. The natural fluctuations of many of these indices in or- 

 ganisms are so wide that changes produced by chronic toxic action are usual- 

 ly unrecognizable. The picture is further complicated by the varying re- 

 actions of the organisms under the influence of toxic substances in varying 

 environmental conditions. 



^Moscow State University, Biological Faculty, Lenin Hills, Moscow, USSR. 



138 



