Occurrence profiling, risk assessment, and correlations of antimicrobials in surface water and groundwater systems in Southwest Nigeria

The presence of antimicrobials in water has grown into a major global health concern. This study thus focused on the presence, ecological implications, and potential health risks associated with nine antimicrobials: five antibiotics (ampicillin, chloramphenicol, ciprofloxacin, metronidazole, and tetracycline) and four parabens (methylparaben, ethylparaben, propylparaben, and butylparaben) in surface water and groundwater samples collected from three Southwestern States in Nigeria (Osun, Oyo, and Lagos States). These antimicrobials were widely detected across the three States with ciprofloxacin being the most dominant having maximum average concentrations of 189 μg L-1 and 319 μg L-1 in surface water and groundwater respectively. The range of average concentrations of antibiotics in surface water are 47.3-235 μg L-1 (Osun), 27.9-166 μg L-1 (Oyo) and 52.1-159 μg L-1 (Lagos). For groundwater, it is 35.3-180 μg L-1 (Osun), 26.5-181 μg L-1 (Oyo) and 32.3-319 μg L-1 (Lagos). The average concentrations of all parabens were 32.4-153 μg L-1, 53.4-80.1 μg L-1, and 83.2-132 μg L-1 for surface water and 46.7-55.7 μg L-1, 53-117 μg L-1, and 62.4-118 μg L-1 for groundwater in Osun, Oyo, and Lagos States respectively. Methylparaben was most frequently detected paraben with average concentrations of 153 μg L-1 and 117 μg L-1 in surface water and groundwater respectively. The measured environmental concentrations of these antimicrobials pose a significant ecological risk while those of ciprofloxacin and ampicillin pose a high health risk to all population groups studied. The average concentrations of antibiotics investigated in this study exceeded their threshold values for Predicted No-Effect Concentrations (PNEC) associated with resistance selection, except for tetracycline.

Cellulose-based adsorbents for solid phase extraction and recovery of pharmaceutical residues from water

Cellulose has attracted interest from researchers both in academic and industrial sectors due to its unique structural and physicochemical properties. The ease of surface modification of cellulose by the integration of nanomaterials, magnetic components, metal organic frameworks and polymers has made them a promising adsorbent for solid phase extraction of emerging contaminants, including pharmaceutical residues. This review summarizes, compares, and contrasts different types of cellulose-based adsorbents along with their applications in adsorption, extraction and pre-concentration of pharmaceutical residues in water for subsequent analysis. In addition, a comparison in efficiency of cellulose-based adsorbents and other types of adsorbents that have been used for the extraction of pharmaceuticals in water is presented. From our observation, cellulose-based materials have principally been investigated for the adsorption of pharmaceuticals in water. However, this review aims to shift the focus of researchers to the application of these adsorbents in the effective pre-concentration of pharmaceutical pollutants from water at trace concentrations, for quantification. At the end of the review, the challenges and future perspectives regarding cellulose-based adsorbents are discussed, thus providing an in-depth overview of the current state of the art in cellulose hybrid adsorbents for extraction of pharmaceuticals from water. This is expected to inspire the development of solid phase exraction materials that are efficient, relatively cheap, and prepared in a sustainable way.