Microbiotests for the evaluation of the pollution from the oil shale industry

Abstract

In this study a comparative chemical and toxicological analysis of 8 phenolic river water and wastewater samples originating from the Kohtla-Jarve oil shale industry region (north-western part of Estonia) was made. The total phenolic content of the samples ranged from 0.01 to 195 mg/1. For 5 wastewaters the corresponding synthetic phenolic analogues were prepared. A battery of biotests was applied to study the toxicity of environmental wastewaters and their synthetic phenolic analogues. The battery consisted of 3 crustacean tests (Daphtoxkit F™ magna, Daphtoxkit F™ pulex, Thamnotoxkit F™), one protozoan test (Protoxkit F™), one rotifer test (Rotoxkit F™), one algal test (Algaltoxkit F™) and 3 photobacterial tests (Microtox™, BioTox™ and Vibrio flscheri 1500). The observed toxicity correlated with the amount of phenolic compounds in the samples. The most sensitive tests in the battery were the Daphtoxkit F™ magna and the photobacterial tests. The comparison of the toxicity of environmental wastewaters and their synthetic phenolic analogues showed that, in general, the environmental wastewaters exhibited higher toxicity than the analogues. For some samples and some tests the difference was as high as a factor 75. This study again shows that (exclusive) chemical analysis is inadequate for toxicity prediction and should be complemented by ecotoxicological testing.