The Use of Algae’s Photosynthetic Activity in Toxicity Assessment with the Purpose of Creating Portable Devices

Abstract

The choice of test organisms and test reactions to be used in biotesting devices for wastewater toxicity, including portable ones, is caused by such factors as ease of cultivation and keeping test organisms in the laboratory, relatively high sensitivity to toxic substances, possibility of instrumental recording of physiological indicators used as test reactions on toxicity, a short time from the beginning of the toxicant action to the appearance of changes in the test reaction. Based on these criteria, we can assume that algae are a fairly convenient test organism for instrumental methods of biotesting since they have the a great deal advantages. Purpose. To find the best options for assessing the photosynthetic activity of algae. Methods. The polarography method. Results. The authors have analyzed dependence of the main characteristics of the sensor on the structure of the diffusion layer and temperature and have found out that the optimal choice of the structure can be made depending on the biological object and experimental conditions. The research has shown that test reactions characterizing physiological state of algae are very diverse. This facilitates their choice for the purposes of instrumental toxicity biotesting, including biotesting toxicity of wastewater with portable instruments. Analysis of the experimental data has shown that it is possible to achieve the difference between concentrations of dissolved oxygen in a liquid culture before and after the exposure of the algae of 1-8 mg / l in a sufficiently short period of time by adjusting the density of algal cultures and light intensity. This indicates the fact that in principle it is possible to quantify photosynthetic activity of algae at short time intervals when exposed to light. Conclusions. The most promising method for assessing the photosynthetic activity of algae is the polarography method, which makes it possible to develop a portable instrument for wastewater toxicity biotesting.