Multigenerational effects of two glucocorticoids (prednisolone and dexamethasone) on life-history parameters of crustacean Ceriodaphnia dubia (Cladocera)

Occurrence, Fate, Effects, and Risks of Dexamethasone: Ecological Implications Post-COVID-19

“…DEXA exposure to F3 yielded mean offspring numbers of 4.6 and 9.2 at 62.5 and 15.6 µg/L, respectively, compared to 17.8 in control groups, with a significant reduction in reproduction at 3.9 µg/L (p < 0.05) (Bal et al, 2017). The higher toxicity of DEXA at lower concentration(s) is likely due to the presence of the fluorine atom at the 9α position, responsible for increased glucocorticoid, which, in turn, slows down metabolic activity [91].…”

“…Studies have demonstrated the deleterious effects of DEXA on non-target aquatic taxa (e.g., fish, crustaceans, algae, and bacteria) at different levels of organization (Table S1). In summary, potential effects of DEXA to aquatic taxa include an increase in bacterial doubling time [42]; inhibition or promotion of growth and chlorophyll-a content in algae [44,48]; mortality, reproduction inhibition, and population growth in crustaceans [44,87]; and inhibition of growth and reproduction performance in fish [47], among others (Figure 2). Findings have demonstrated potential deleterious toxicological outcomes of DEXA to aquatic taxa, dependent on various factors.…”

“…Two parallel sets of toxicity bioassays were run for up to four consecutive generations (F0-F3) of C. dubia. Short-and long-term effects of DEXA to crustacean C. dubia included acute immobilization (50-3200 µg/L) and multigenerational chronic effects (fecundity, average time to first brood, mean brood size, body length) (1.95-125 µg/L) [87]. Based on the 48 h-EC 50 results, DEXA was very toxic (EC 50 = 750 µg/L), but no significant differences were observed in the controls as a function of generation.…”

“…Reproduction inhibition was observed in F0 at a test concentration of 62.5 µg/L. Further, due to high reproduction inhibition and consequent mortality at 125 µg/L in F1, progeny from the third brood (F2) was inadequate to continue the next generation (F3) [87].…”

“…Current literature, as discussed in Section 4.1, shows conventional WWTPs can efficiently remove DEXA from municipal influent, especially at low concentrations [113,114]. However, influents with higher DEXA concentrations, e.g., from hospitals and the animal husbandry sector (e.g., swine farms), are ineffectively remediated using biological secondary treatment processes, with concomitant significant environment concentrations detected in the effluent [87]. Depending on the water quality requirements for the effluent discharges with respect to public and environmental health, tertiary treatment technologies are required to remove the remaining DEXA post-primary processes [24,103,115], as the results in Table S2 demonstrates.…”