SECTION 10 



EXPERIMENTAL TESTING OF TOXICITY OF WATER MEDIA AND INCREASING 

 OF THE SENSITIVITY OF BIOLOGICAL TESTS 



L.P. Braginski, V.D. Bersa, T.I. Birger, I.L. Burtnaya, 

 F.Ya. Komarovski, A.Ya. Malyarevskaya, E.P. Shcherban 



General increase of anthropogenic pollution of the hydrosphere raises 

 the problem of quantitative and qualitative characterization of pollu- 

 tants and evaluation of their biological danger. Additionally, the ques- 

 tion of establishing analytical and control methodologies of wide applica- 

 bility for assaying the toxicity of the water medium based on evaluation 

 of biological effects of toxicants is of paramount importance. One of 

 the principal ways of solving the problem is the application of biologic 

 tests. These tests have enjoyed wide spread acceptance in Europe 

 (Bringmann and Kuhn, 1959; Liebmann, 1960; Stanislawski , 1969), in the 

 USA (Katz, 1971; Environmental Protection Agency, 1972; Federal Water 

 Pollution Control Administration, 1969) and in the USSR (Braginski, 1971; 

 Lesnikov, 1971; Anon., 1959; 1971, 1966; Stroganov, 1971). 



The main advantage of the biological tests are simplicity and avail- 

 ability of methodology, high sensitivity of the test organisms to the 

 minimum concentrations of toxic agents, speed, and the fact that expen- 

 sive reagents and equipment are not required. The main principle of bio- 

 logical testing is extremely simple. It is used to establish confident 

 differences between the experiment (medium containing toxicant) and the 

 control (clean water) in any indicative biological parameter test or- 

 ganism. Both alternative (life-death) and graded (percent of the experi- 

 ment as contracted with the control) experiments are used to indicate com- 

 plete or partial inhibition of essential functions of test organisms 

 under the influence of the test water or toxicants in certain concentra- 

 tions. 



Discrimination between two types of test organisms is made: 1) indi- 

 cative, and 2) representative ones. The first category implies the use 

 of organisms with the greatest degree of sensitivity to toxicants, the 

 second implies the use of organisms that most fully represent a given 

 ecosystem (the crustacean EptAkuia. in Lake Baikal, Mij^li in the Danube 

 estuaries, and so on). 



When choosing test organisms, one is compelled to account for their 

 individual ecological specificity, their restriction to certain type of 

 waters, lentic or lotic environmental requirements, typical habitats 



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