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

Abstract

ABSTRAC: 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. @ JASEM Pollution of water bodies with heavy metals from variety of sources is becoming a matter of global concern (Dike et al., 2004). Though effects of chemical contamination of drinking water are not felt on short-term bases (except nitrate), their accumulation over a long period in the body has significant health effects (Musa et al., 2004). Sokoto metropolis has been facing a lot of water supply problems, some of which are of great public health significance (Junaidu et al., 2001), and one of such problem is improper treatment of water at the Sokoto Water Works, and broken down pipes among others which buttressed the findings of Ibrahim et al (2000) that showed that Sokoto State lacks safe drinking water and has environmental sanitation problem. So far, studies carried out in this environment focused only on the bacteriological quality. Aspects such as chemical contamination of drinking water which have not been investigated is the basis for this study. Therefore, the aim of this research is to characterize the physico-chemical-heavy metal quality of drinking water sources in Sokoto metropolis.