Rainwater Quality Index of Selected Communities in Langtang North and South Local Government Areas, Plateau State North-Central Nigeria

This study examines the portability of rainwater in Langtang north and south LGAs of Plateau State-Nigeria using arithmetic water quality index method with 10 samples collected directly from zinc and aluminum rooftops in 10 selected communities. Twenty-six water quality parameters were analyzed in the field and laboratory. Temperature, pH, EC, TDS and turbidity were analyzed in the field using appropriate equipment as well as color, odour and taste. The most probable number was used to determine the presence of bacteria, while photometric and the Atomic Absorption Spectrophotometer (AAS) were used to determine the concentration of the various chemical parameters (USEPA, 2012). The results revealed unobjectionable taste, color and odour, temperature (26.8-27.5), pH (6.5-7.8), Turbidity (1.8-2.7), Conductivity (20-30), TDS (10-15), Caco3 (5-10), Ca (2-8), Mg (1-4), SO4 (1-7), NO3 (1.3-8.6), Fe (0.01-0.15), Cl (10-32), F (0.001-0.002), Cu (0.01-0.2), Zn (0-1.5), Mn (0-0.02), Cr (0-0.01), Al (0.01-0.06), and total coliform (0-4). Cadmium, Arsenic, Lead, phenols, pesticides, faecal coliform and e-coli were not detected. All parameters tested were within acceptable limits for drinking water. While aluminium catchments do not show any difference in parameter concentrations, zinc catchment revealed increase in Zn concentration with age of materials. Calculated water quality index of samples ranged from 2 to 12 with an overall value of 4.7 indicating excellent water quality for all samples. Based on these results, the paper concludes that the rainwater is of good quality suitable for drinking. However, age of catchment materials may influence rainwater quality in due course through leaching, and therefore recommended regular maintenance of catchments, observance of first flush and avoid use of old roof for RWH.