Response to Comments on the reduction in emerging contaminants in water samples from the Esmeraldas Coast (Ecuador)

Abstract

We read with great interest the recent article by Cipriani-Avila et al., where the authors showed that pharmacological micropollutants (indicated as emerging contaminants, ECs), reported in water samples of Esmeraldas Coast (Ecuador) throughout 10 river mouth sites and 14 coastal sites, exhib ited a marked difference in concentration between two different annual pe riods, one of which characterized by COVID-19-caused social restrictions and lockdowns (Cipriani-Avila et al., 2023). Briefly speaking, the authors evaluated the concentration in the indicated samples of at least four commonly used pharmaceutical drugs (acetaminophen, diclofenac, sulphomethoxazole and trimethoprim) and of caffeine, in two different ex perimental settings, i.e., in a COVID-19-free period (November 2019) and during the COVID-19 pandemic (November 2020), in order to use drugs as ECs of anthropic presence. I found the idea to assess the dynamic of COVID-19 pandemic by detecting ECs in the environment very intriguing, yet some questionable issues were raised when I thoroughly read the paper. The analytical chemistry of ECs determination (Cipriani-Avila et al., 2023), appeared to account only on the native bioactive molecule in the en vironment, not to any further degraded by-product from the same molecule due to organic or biological catabolism. This may be fundamental to ascer tain microbiological activity on those molecules within the tested environ ment. The authors reported that environmental parameters in river mouths and coastal sites, particularly for temperature, differed significantly. More over, Cipriani-Avila et al., showed that there was a clear spatial relationship in the concentrations of these micropollutants in different coastal sites, as all the pharmaceutical drugs were detected in at least two of the fours coastal sites investigated and all reached a drastic reduction during the COVID-19 period (Cipriani-Avila et al., 2023).