Search

Groundwater quality and its potential health risk around a municipal dumpsite in Ikire, Southwest Nigeria was investigated using ten groundwater samples which were analyzed for physicochemical parameters. The methods used were groundwater sampling, analyses, spatial distribution of heavy metal (Cd, Cr, Cu, Fe, Mn, Pb, and Zn) and quantitative health risk analysis using USEPA equations. The chronic daily intake (CDI), hazard quotient (HQ), and hazard index (HI) were used to examine potential human health risks of heavy metal pollution. The mean concentration values of Cl−, Ca2+, K+ Mg2+, Fe, Cd, Pb and Mn were higher than their respective permissible limits, while the mean concentration values HCO3−, Cu and Zn were within their respective limits. The HQ values of the heavy metals via oral ingestion for the children and adults are found in the order: Cd > Pb > Mn > Fe > Zn > Cu and Cd > Pb > Mn > Zn > Cu > Fe, respectively. The HI values via ingestion pathway for all heavy metals were beyond the threshold value of 1.0, indicating high contamination adverse health risk due to an undesirable level of heavy metals. Cadmium is a major contributor to non-cancer effects in children and adults in the groundwater samples in the region. The groundwater is unsafe for drinking and should be treated before domestic consumption.

Purpose – The quality of groundwater in the vicinity of petroleum products retailing stations in Ile-Ife, Nigeria was investigated with a view to providing valuable information on the organic and other physico-chemical parameters associated with the contamination of the groundwaters by petroleum products. The paper aims to discuss these issues. Design/methodology/approach – Three sets of samples were collected per season from artesian wells within petroleum products retailing stations for polycyclic aromatic hydrocarbons (PAHs), trace metals and other physico-chemical parameters analysis. Extraction, cleaned-up and concentration of the PAHs were done using certified analytical methods. Levels of the PAHs and metals were determined using gas chromatography coupled with flame ionization detector and bulk scientific atomic absorption spectrophotometer, respectively, while other pollution indicators were measured using standard analytical procedures. Findings – The groundwaters contained elevated levels of PAHs, Cu, Zn, Mn, Pb, Cr, V, Ni, Fe and total dissolved solids than their maximum allowable limits for drinking water. Analysis of variance (ANOVA) results confirmed that both seasonal variation and location had much influence on the levels of most of the analyzed parameters. Some of the parameters showed strong positive correlation with each other, while Cr/Pb and Na/Pb displayed strong negative correlation with each other, indicating similar source(s) and/or chemical affinity and vice versa, respectively. Cross-plot analysis results using metals and PAHs concentrations as variables showed significant positive correlations (R2=0.99) and (R2=0.60), respectively, suggesting similar source(s) of contamination of the two sets of samples. Originality/value – The level of the groundwater contamination was an indication of indiscriminate discharge of petroleum products and/or underground tank leakage within the study areas.