Physico-chemical Quality and Diversity of Cysts of Enteropathogenic Protozoa in Water from Wells and Boreholes in the City of Douala, Cameroon
Kapso Mireille, Mbog Diazine, Chinche Belengfe, Koji Ernest, Nguepidjo Gilbert, Teukam Willy et 6 autre(s)
International Journal of Sustainable Development Research
In developing countries, access to drinking water in urban areas is limited. People living in certain neighbourhoods rely on wells (W) and boreholes (B) for their water needs. The aim of this study was to assess the physico-chemical and biological quality, and in particular the diversity of enteropathogenic protozoa present in this commonly used water in the city of Douala. Bi-monthly water samples were collected at 12 water points from July 2023 to March 2024. The physicochemical analyses consisted of measuring temperature, pH, salinity and total dissolved solids using a Water quality tester (WQT) multimeter model EZ-9909SP. Protozoans were isolated by direct slide staining, tube staining and concentration methods before observation under a light microscope at 40X magnification. The results show that the groundwater studied is acidic (pH =5.6±0.07 UC), with a salinity of up to 0.3 USP and rich in Total dissolved solids (TDS) (86 to 400 ppm). Biological analyses revealed the presence of 4 groups of protozoa and 11 species. Enteric protozoan cysts were mainly represented by rhizopods, with mean densities of 116 ± 23 cysts/L in well W1 and 96 ± 37 cysts/L in well W3. In well W6, flagellates reached a peak of 40 ± 6 cysts/L. In the well water, ciliates were virtually absent, while rhizopod cysts were more abundant in B1 (60 cysts/L) and B6 (34 cysts/L). Sporulated forms were present in the borehole water with an average density ranging from 14 (B1) cysts/L to 32 cysts/L (B5). On a time plan, the highest abundance was recorded in the dry season. Significant positive correlations were observed between flagellate viability and TDS (r= 0.324; p=0.000). Ciliates were significantly and positively correlated with salinity (r= 0.324; p=0.000). Rhizopods are inversely correlated to TDS (r= -0.181; p=0.030). The exogenous matter brought in by pollution considerably increases the adherence of cysts in biofilms and hence their abundance. Analysis has identified pH non-compliance as a critical and widespread water quality issue affecting all sampled wells and boreholes during both the rainy and dry seasons As recommendation, to suspend use of W3 for direct drinking water until pH correction is implemented. W3 recorded the lowest pH (~4.0–4.5), representing the highest health risk. Advise boiling and pH correction prior to consumption until permanent treatment is in place. Deploy pH correction units as an emergency measure at W1–W5 and all borehole sites.