CNTs coated charcoal as a hybrid composite material: Adsorption of fluoxetine probed by zebrafish embryos and its potential for environmental remediation.

Although traditional water treatment systems can remove various substances from wastewater, these conventional systems fail to remove many chemical molecules that pose potential ecological and health risks. Carbon nanotubes (CNTs) appear attractive to adsorption of many substances, but CNTs adsorbed with toxic substances becomes a nanocomposite still more toxic. Here, we employ zebrafish embryos as biosensor to examine how a hybrid micro/nanostructured carbonaceous material (HMNC) derived from a combination of activated carbon (AC) with hydrophilic carbon nanotubes (CNTs) can remediate wastewater contaminated with the pharmaceutical fluoxetine hydrochloride (FLX). AC and HMNC are practically non-toxic to zebrafish embryos (LC50 > 1000 mg.L-1). HMNC addition to culture medium containing FLX significantly reduces sublethal effects and lethality. Interaction between FLX and HMNC involves chemical adsorption such that embryo co-exposure to HMNC adsorbed with FLX in the range of concentrations evaluated herein does not elicit any behavioral changes in zebrafish.

Exposure to dilute concentrations of bupropion affects zebrafish early life stages.

Psychiatric pharmaceuticals are one of the most prescribed active substances globally. Bupropion (BPP) is an antidepressant that acts via inhibition of norepinephrine and dopamine reuptake. It has been found in various water matrices, and thus its effects on aquatic organisms must be studied. The present study aimed to evaluate the acute toxic effects of BPP on zebrafish (Danio rerio) early life stages. For developmental analysis, organisms were exposed for 168 h to concentrations ranging from 0 to 82000 µg/L. Two other experiments were performed by exposing embryos to a wide range of concentrations (from 0 to 50000 µg/L) in order to evaluate BPP effects on embryonic behavior, using the Zebrabox and testing at the biochemical level (acetylcholinesterase, glutathione-S-transferase, lactate dehydrogenase and catalase). Developmental analysis indicated that BPP had low acute toxicity with a calculated 168 h-LC50 of 50346 µg/L. Concentrations equal to or above 44800 µg/L elicited several effects such as hatching delay, edemas and tail deformities. However, concentrations from 7300 µg/L upwards elicited equilibrium alteration. Behavioral analysis showed that BPP affected zebrafish locomotor behavior by decreasing activity at 0.6 µg/L, increasing activity at 8.8 and 158 µg/L, and decreasing activity at 50000 µg/L. Biochemical analysis showed an increase of AChE activity at 158 and 2812 µg/L, an increase in GST at the highest concentrations, CAT alteration and increase of LDH at 0.6, 2812 and 50000 µg/L. We can conclude that BPP affects zebrafish early life stages at environmental concentrations.