Environmental toxicity of selected aminoglycoside antibiotics to Lemna minor

Aminoglycoside antibiotics (AGs) are widely used in human and veterinary medicine. After administration, AGs undergo minimal metabolism and are excreted in their active form, contributing to their presence in the envi ronment. The aim of our study was to determine the ecotoxicological characteristics of five AGs commonly used in human and veterinary medicine: gentamicin, neomycin, spectinomycin, streptomycin and dihydros treptomycin. Their effects on growth and chlorophyll synthesis were investigated under laboratory conditions using the model plant organism Lemna minor. For each AG, logarithmic dilution was performed to yield test solutions with concentrations ranging from 0.001 to 100 mg/L. In the growth inhibition test, low concentrations of spectinomycin and streptomycin stimulated the growth of Lemna minor. The lowest EC₅₀ values, indicating the greatest toxicity, were detected for gentamicin and dihydrostreptomycin, at 0.397 and 0.625 mg/L, respectively. The results of the chlorophyll synthesis test revealed that neomycin and gentamicin had the lowest EC50 values, at 45.33 and 56.01 mg/L, respectively. The other AGs tested did not notably affect chlorophyll synthesis.