Acute toxicity of escitalopram to the Antarctic freshwater copepod Boeckella poppei

Authors: Miguel Jorge Lourenço Domingos, Alexandra Warkentin, Caio Cesar Ribeiro

Affiliations: for each author ECHO - Ecotoxicology and Chemical Oceanography Group, Centre of Marine Sciences (CCMAR), University of Algarve, Faro, Portugal.

Abstract: Antidepressants can reach polar waters through human activities, but toxicity data for Antarctic freshwater invertebrates remain scarce. We tested the acute toxicity of escitalopram to adult Boeckella poppei collected from ponds near the Great Wall Antarctic Station, King George Island. Copepods were exposed under static conditions for 48 h at 4 ± 0.5 °C and a 16:8 h light:dark cycle, across nominal concentrations from 0 to 100,000 µg L⁻¹. The estimated 48 h LC50 was 75,000 µg L⁻¹ (95% confidence interval: 57,800–97,400 µg L⁻¹). No mortality was reported at concentrations up to 10 µg L⁻¹; the study reports a NOEC of 10 µg L⁻¹ and a LOEC of 100 µg L⁻¹. These results provide an initial acute toxicity benchmark for a polar freshwater copepod and show how a bioassay conducted at low temperature can address species and conditions absent from standard temperate testing. Further work should verify exposure concentrations and examine sublethal responses and longer exposure periods.

Keywords: escitalopram, Boeckella poppei, Antarctic freshwater, copepod, acute toxicity, polar ecotoxicology