Physico-chemical characteristics and Heavy metal levels in Drinking Water sources in Sokoto metropolis in North-western Nigeria

This study investigated the physico-chemical characteristics of drinking waters collected from tap, well and sachet in Sokoto metropolis in North Western Nigeria. Conductivity and pH values were determined by standard methods while elemental composition was analysed using X-ray Fluorescence spectroscopy. Majority of the water samples had neutral pH (6.80 – 7.20) few were slightly alkaline and one was acidic. Tap water samples had similar conductivity values (180 -190μS/m), sachet water samples had conductivity values ranging from 80μS/m to 260μS/m while well water samples had highest conductivity values with a sample having value above standard limit of 1,500μS/m. Heavy metals (copper and lead), rare earth metals (gallium, rubidium, strontium and vanadium) and other elements (potassium, calcium, chromium, manganese, iron, cobalt, nickel, zinc, arsenic, selenium, bromine and molybdenum) were detected. Result of elemental analysis showed the presence of 18 compounds in the different water samples, of which seven, namely: As, Cr, Mn, Pb, Ni, Se and Br had levels above WHO recommended permissible limits, with their attendant health implications. Generally, all the sampled waters analysed in this study failed chemical tests and therefore not suitable for drinking.