Evaluation of the aquatic toxicity of two veterinary sulfonamides using five test organisms

Toxicity of the veterinary sulfonamide antibiotic sulfamonomethoxine to five aquatic organisms

“…Studies have reported that other veterinary SAs exhibit chronic toxicity to daphnids higher than that observed in the present study. For example, two SAs, sulfaquinoxaline and sulfaguanidine, have been observed to inhibit reproduction in D. magna when the EC 50 values were 3.47 and 0.87 mg L −1 , respectively (De Liguoro et al, 2010). In another study, the EC 50 of sulfamethazine for D. magna was 4.25 mg L −1 (De Liguoro et al, 2009) and was lower than that observed in the current study.…”

“…Furthermore, discrepancies in the toxicity of SAs to aquatic organisms have been reported; some studies have reported significant toxic effects (De Liguoro et al, 2010;Eguchi et al, 2004;Isidori et al, 2005), whereas other studies have not (Lin et al, 1993). These discrepancies might be due to differences in the sensitivity of the tested organisms and criteria used for defining the toxic effects (Baran et al, 2011).…”

Toxicity of four sulfonamide antibiotics to the freshwater amphipod Hyalella azteca

“…The majority of toxicity tests conducted with SAs are short in duration (i.e., on the order of hours, days, or weeks) and measure acute end points (i.e., lethality, immobility); these tests may not accurately assess environmental impacts because aquatic ecosystems receive continuous inputs of these compounds 7 and, therefore, environmental exposures occur over an extended period of time. Chronic effects in crustaceans also occur at lower concentrations than acute effects: LC50s for Hyalella decreased from weeks 1 to 4 in the present study, and EC50s for reproduction occurred at concentrations an order of magnitude lower than EC50s for immobility in Daphnia exposed to SAs 12, 13. Therefore, long‐term, low‐level exposures such as those that occur in aquatic ecosystems could affect sensitive chronic end points at environmentally relevant concentrations.…”

“…To our knowledge, this is the first time the toxicological effects of SAs have been studied in Hyalella . Previous research on the toxicity of SAs to freshwater invertebrates has been conducted primarily on two crustaceans, Ceriodaphnia dubia and D. magna (Table 5); acute toxicity (24–96 h) ranges between 18 and 2,060 µM (nominal), and chronic toxicity (7–21 d) ranges between 0.83 and 55 µM (nominal) 12–20. When comparing the toxicity of the specific SAs tested in our study, the acute effects of SG, ST, and SM occurred at concentrations sevenfold, more than sixfold, and up to 39‐fold lower, respectively, in Hyalella than in Daphnia , while the chronic effects of SG occurred at fourfold lower concentrations (Tables 4 and 5).…”

“…In particular, freshwater invertebrate species are underrepresented in the published literature. Several studies have been published on the toxicity of a variety of SAs to freshwater invertebrates, but only two species have been tested in these studies: Daphnia magna and Ceriodaphnia dubia 12–20.…”