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Analyses of source water samples from three areas in South Africa for estrogenic activity and oxidative stress

dataset
posted on 2024-02-15, 09:02 authored by Naledi MmekwaNaledi Mmekwa

These dataset contains concentration–effect curves and oxidative stress response results from the AREc32 reporter gene assay (table 1). Samples were analyzed in replicate through bioassays, and screening for the presence of pharmaceuticals using ultra-high performance liquid chromatography system. During data analysis, the results for each replicate were compared to ensure that the variability did not exceed a pre-determined level. The average of the intra-assay replicates was then used as a single number. The concentration–response curve for all repeats was also evaluated together. The final result was reported as the average of the two closest results.

Estradiol equivalent concentrations (ng/L) in source water from Gauteng (GP), Mpumalanga (MP), and Limpopo (LP) provinces, South Africa, using the yeast estrogen screen (YES) (Table 2). The following equation was applied to correct for turbidity: corrected value = test abs (540 nm) – [test abs (620 nm) – median blank abs (620 nm)]. The detection limit of the yeast assay was calculated as absorbance induced by the solvent control (blank) plus three times the standard deviation. Sample concentrations with absorbance values below the solvent control minus three times the standard deviation were considered cytotoxic concentrations. The estradiol equivalents (EEq) of the samples were interpolated from the estradiol standard curve and corrected with the appropriate dilution factor for each sample. This was calculated for samples with 3 or more points above the detection limit. EEq values were reported as the average ± SD of three independent repeats.

Pharmaceutical compounds were detected using the Dionex Ultimate 3000 UPLC (table 3). Compass Data Analysis 4.3 (Bruker, Germany) software package together with the tools found in the software package such as compass isotope pattern and compound crawler were used in the screening workflow. Accurate mass measurements of each peak from the extracted ion chromatograms were obtained using a sodium formate calibrant solution delivered by a Kd Scientific external pump. The function edit chromatogram was used to obtain the extracted ion chromatogram (EIC) of each compound using their molecular formula. MS/MS spectrum of each compound was then obtained using the find compound spectra function in the data analysis. The compound crawler function in the Data Analysis 4.3 software was used to confirm that the peak represents the suspect compounds in online databases of KEGG (Kyoto Encyclopedia of Genes and Genomes), CHEBI (Chemical Entities of Biological Interest), HMBD (Human Metabolome Data Base), and FOR-IDENT. Parameters used in screening were mass accuracy ≤5 ppm, isotopic fit (mSigma) less than or equal to 100, signal-to-noise ratio of 3, minimum intensity threshold of 500, and presence of a minimum of one production.


Funding

Water Research Commission (WRC)

History

Department/Unit

Environmental Chemical Pollution and Health Research Unit

Sustainable Development Goals

  • 6 Clean Water and Sanitation