Ecotoxicological effects of ciprofloxacin on freshwater species: data integration and derivation of toxicity thresholds for risk assessment

Abstract

Although antibiotics have been increasingly used and detected in natural samples, their ecotoxicological effects on aquatic wildlife are not yet extensively studied. Considering the environmental threat posed by the biological activity of antibiotics it is quite relevant to assess the resulting impact, especially on sub-lethal endpoints. As such, this study evaluated the effects of ciprofloxacin on Pseudokirchneriella subcapitata and Lemna minor growth, on the survival and reproduction of Daphnia magna and on Gambusia holbrooki survival. The risks associated with ciprofloxacin effects on non-target organisms were quantified through the calculation of the PEC/PNEC ratio. Overall, the toxicity values obtained (at the mg L(-1) level) were higher than the environmental concentrations. P. subcapitata and L. minor were more sensitive under short-term exposures than D. magna and G. holbrooki. No acute toxicity was observed for fish. The chronic assay with D. magna evidenced that long term exposures to lower concentrations of this antibiotic induced impairments on its life-history parameters. Such outcome may pre-empt potential damages on the long-term maintenance of natural populations continuously exposed to the input of antibiotics. Indeed, the PEC/PNEC ratios showed that ciprofloxacin represents a risk for the most sensitive aquatic organisms, since the defined threshold of an acceptable risk was considerably surpassed.

Lethal/sublethal responses of Daphnia magna to acute norfloxacin contamination and changes in phytoplankton-zooplankton interactions induced by this antibiotic

“…Thus, the grazer density used here (3 individuals mL −1 ) was similar to that used in previous studies on acute toxicity39. D. magna individuals were not fed during the test periods following previous studies394243.…”

A review on emerging contaminants in wastewaters and the environment: Current knowledge, understudied areas and recommendations for future monitoring

“…Toxiclogical effect information gained from current ecotoxicity testing which use racemic mixtures may therefore underestimate the risk actually posed in the environment. Findings from racemic toxicity testing have been used to recommend predicted effect/no effect concentrations (Ferrari et al, 2004;Quinn et al, 2008a;Martins et al, 2012) and can be seen as a precursor for environmental legislation and the proposal of quality standards. Although environmental legislation has safety buffers incorporated into their derivation, failure to recognise the enantiomeric distribution of chiral compounds in the environment and a lack of information on the toxicological differences between enantiomers is concerning.…”

Ecotoxicological effects of enrofloxacin and its removal by monoculture of microalgal species and their consortium

“…has been widely practiced, because of the higher sensitivity of algae compared to that of other microorganisms (bacteria, fungus, daphnids, and fish) toward the environmental stresses, which can induce the overaccumulation of reactive oxygen species in microalgae cells (Robinson et al, 2005;Isidori et al, 2005;Martins et al, 2012;Xiong et al, 2016Xiong et al, , 2017b. Risk assessment of 14 different antibiotics also showed that algae were more sensitive to the antibiotics than daphnids and fish (Yao et al, 2017).…”