Abstract: The physicochemical quality of municipal water from three waterworks
in Osun State, Nigeria was monitored in terms of temperature, pH, electrical
conductivity, dissolved oxygen, solids (total, suspended and dissolved),
nitrates and phosphates from April, 2003 to March, 2004 in order to assess the
adequacy of treatment at the waterworks. The trace metal levels as well as the
microbial quality of the municipal water from these waterworks were also
monitored for the same length of time to establish their pollution levels. The temperature values varied between 24.6°C and 32.0°C. The annual mean pH
values for the three municipal water varied between 6.92 and 7.54 and therefore
conforms with the WHO guideline of <8.0 in drinking water. The electrical
conductivity values obtained ranged from 120.05 μS/cm to 265.00 μS/cm. The mean levels of oxygen-demanding substances, nitrate, phosphate, total solids and
dissolved solids were generally low and ranged from 6.23 mg/l to 8.99 mg/l; Not
Detected (ND) to 2.59 mg/l; ND to 3.56 mg/l; 77.33 mg/l to 180.00 mg/l and
58.27 mg/l to 116.67 mg/l respectively. The concentrations of these substances
were within safe limits. The coliform population varied from zero to 93
coliforms per 100 ml, the total bacteria count ranged between 0.3
× 10^4 Cfu/ml and 45.50 × 10^8 Cfu/ml while
Escherichia coli was rarely detected throughout the study. Among the nine trace
metals of interest only Hg, As and Cd occurred at concentrations above the WHO limits for
drinking water and this give cause for concern
Keywords: Municipal water, trace metals, reservoirs, physico-chemical, contamination
