Phycotoxicity of antibiotics and non-steroidal anti-inflammatory drugs to green algae Chlorella sp. and Desmodesmus spinosus: Assessment of combined toxicity by Box-Behnken experimental design

There is a growing concern regarding the adverse effects of pharmaceutical pollution on aquatic environments. The present study investigated the toxicity of different antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs) on two green algae namely Chlorella sp. and Desmodesmus spinosus. Based on the 96h IC50 values of the two chlorophytes, tetracycline (TET) was more toxic than other antibiotics (ciprofloxacin (CPF) and amoxicillin (AMX)), while paracetamol (PAR) was more toxic than ketoprofen (KET) and diclofenac (DIF). Gross photosynthesis was markedly reduced with most of the investigated drugs, although, the Chl a content was stimulated in a dose-dependent manner. Algal treated cells exhibited elevated malonaldehyde content which reflected several structural and functional cellular damages. Catalase and ascorbate peroxidase (APX) were involved in the reduction of reactive oxygen species, but the effects of APX were more pronounced at low drug concentrations. Box-Behnken design (BBD) was employed to investigate the combined toxicities of PAR, KET, AMX and TET on D. spinosus in response to growth inhibition and pigment increase. The mutual interactions varied between synergism and antagonism. The BBD analysis indicated that the experimental design could be effectively utilized as a useful tool for ecotoxicological assessment. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study investigated the toxicity of pharmaceuticals on green algae, revealing varying degrees of toxicity and cellular damages caused by different drugs. The research also utilized experimental design to study the combined toxicities of different drugs on algae, providing an effective tool for ecotoxicological assessment.