Quality audit of drinking water sources in Ikwo rural setting of Ebonyi State, Southeastern Nigeria

Abstract

We assessed the quality status of surface and ground waters used for drinking in Ikwo, Southeast Nigeria, using the physicochemical and bacteriological qualities, and antimicrobial susceptibility profiles following standard procedures. Overall. the mean values of the physicochemical qualities of the water samples revealed the following: colour (brown/dark-brown/colourless), odour (objectionable), temperature (28–30 °C), pH (6.30–7.50), electrical conductivity (12.94–12.99 µs cm−1), total dissolved solids (7.74–7.80 mg L−1), alkalinity (0.3–1.4 mg L−1), hardness (19–252 mg L−1), chloride (0.8–3.1 mg L−1), copper (0.01–0.72 mg L−1) and zinc (0.03–1.49 mg L−1). Only nitrate was not detected all through. Likewise, total heterotroph, coliform and Escherichia coli counts ranged from 1.16 to 6.96 × 103 cfu mL−1, 150 to 2400 MPN/100 mL and 45 to 345 CFU/100 mL, respectively. The antimicrobial susceptibility profiles showed that the E. coli isolates were relatively susceptible to gentamycin (58%) and levofloxacin (50%), with high percentages of the isolates displaying resistance against tetracycline (78%), norfloxacin (76%), nalidixic acid (76%), augmentin (68%), ampiclox (62%), doxycycline (62%) and amoxil (52%). While the physicochemical parameters were generally within the permissible limits of the WHO guidelines, reverse is the case for the bacteriological loads. Exceedance of bacteriological water quality criteria and prevalence of multidrug-resistant E. coli indicate high levels of microbial and drug pollutants in the waters, rendering them unfit for direct human ingestion without proper pretreatment.