Sustainable access to safe drinking water remains a global problem as more people in the world still consume water from unimproved sources. This study was carried out to evaluate the quality of 12 different water sources and 2 treated water used by a peri-urban town in the Southwest region of Nigeria to assess their suitability for drinking and domestic use. Water quality parameters studied include pH, temperature, acidity, total alkalinity, chloride content and total CO2. A Flame Atomic Absorption spectrophotometer was used to determine the concentrations of Ca, Mg, Cu, Cr, and Pb in the water samples. The total coliform was determined using the most probable number technique while a qualitative method was used to detect the presence of faecal coliform and E. coli in the water samples. All the physicochemical water quality parameters complied with regulatory standards. Similarly, most of the heavy metals also complied except for some sites. Faecal coliform and E. coli tested positive for all the samples except one of the tap water sample. Majority of the water samples (86%) were rated as excellent based on the physicochemical parameters. One sample each was rated as having poor and good water quality, respectively. All the samples tested positive for faecal coliform bacteria and E. coli except one (treated water). It is recommended that Microbial water quality parameters be included in all Water Quality Index (WQI) analyses in order to give the true status of the quality of a water resource.

This paper considered contamination of aquifer resulting from petroleum spillage, which is a common phenomenal in the Niger Delta area of Nigeria. We used the model given by Bestman (1987) and assumed that some endogenous variables are built into the system. To achieve a level of desirable state, we expect the state of water and that of petroleum to be as close as possible within some   neighbourhood. A method to compute a stable control u (.) that will minimise the cost of achieving this desirable state was considered in this paper. We apply the result to a second order system.