Antibiotic ciprofloxacin in water and soil media: reaction of microalgae
A.D. Batakov1, A.P. Kiryushina, D.N. Matorin, V.A. Terekhova
Section: Ecotoxicology
Pharmaceuticals and antibiotics in the environment are of increasing concern due to the impact on representatives of all links in the food chain of natural ecosystems. The effect of the widespread antibiotic ciprofloxacin (Cip) on the green protococcal microalgae Scenedesmus quadricauda and Chlorella vulgaris in water and aqueous soil extracts (artificial standard soil, technosoil, soddy-podzolic soil) was studied in model experiments. Fluorescent parameters were assessed by two different methods (Fluorat 02-5M and Water-PAM devices). The phenomenon of hormesis was observed at low antibiotic concentrations of 5 and 10 mg/L. A decrease in the photosynthetic activity of algae was recorded at an increase of Cip content from 20 to 50 mg/L. A comparison was made of the median (average effective) concentration of the EC50 antibiotic, which suppresses the fluorescent characteristics of microalgae by 50% on 3 days of exposure in different media. The decrease in the toxicity of the studied dose of Cip (300 mg/L) in a number of studied objects can be represented as follows: water > technosoil > artificial standard soil > soddy-podzolic soil. It reflects the percentage of inhibition of the test function relative to the control (samples without antibiotic) by 91.5, 80.0, 62.5, and 60.0% respectively. In the soil matrix, the inhibitory effect of the antibiotic is less pronounced (by 10–30%), probably due to the protective properties of humic substances that adsorb the antibiotic or its metabolites.
ISSN 1995-4301
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