Health risk and pollution associated with trace metals in the waters of the Ebolowa municipal lake basin (Central Africa): evidence from hydrochemistry, quality indices, and statistical analyses.

The aim of this study was to investigate the status of trace metals (As, Cr, Cu, Ni, Pb, Fe, and Zn) and health and carcinogenic risk associated then in the Ebolowa Municipal Lake (EML) basin. To this end, 21 water samples were collected from the EML and its two tributaries, Mfoumou and Bengo'o, and analyzed by Quantofix method (nanocolors and visiocolor ECO) by using the MACHEREY-NAGEL photometer. The data were processed using multivariate statistics. The results showed that all the physicochemical parameters (pH, EC, and TDS), with the exception of TDS, comply with were within WHO limits. The distribution of trace metals at the three sites investigated was as follows: Zn (80-400 ± 1.58 µg/L) > Cu (50-150 ± 9.38 µg/L) > Fe (10-40 ± 0.71 µg/L) > Pb (1-20 ± 3.02 µg/L) > As (1-9 ± 0.44 µg/L) > Ni (1-9 ± 1.48 µg/L). However, the highest values were observed in the EML and the Mfoumou River, where Pb pollution was noted. Statistical analysis showed that anthropogenic inputs increase the presence of Cr, Cu, Pb, and Zn. Trace Metal Pollution Index values were below 15 at all sites, illustrating low levels of pollution. The trace metal evaluation index values for the Bengo'o stream are pure (mean = 0.6), slightly affected in the Mfoumou stream (mean = 2.0), and moderately affected in the EML (mean = 2.2). The toxicity load index values illustrate that the waters studied are toxic. The non-carcinogenic (HI) and carcinogenic (CR) health risk index values suggest a risk linked to oral ingestion in the LME and Mfoumou watercourses. The latter appears to be the main source of allochthonous pollutant input to the EML.