Pollution status of drinking water sources proximal to dumpsites: insights from diverse geo-environmental settings in Nigeria

Clean and potable water is an essential investment for good health. This study investigated the impacts of dumpsites on groundwater quality in Ondo State, Nigeria, and analyzed groundwater contamination across different geological environments in the country; using multi-pollution indices and statistical analyses. Water samples from sixteen wells and two streams (Well 1-Well 16, Stream 1 and 2) around the three dumpsites were collected and analyzed for pH, total dissolved solid (TDS), electrical conductivity (EC), sodium (Na), calcium (Ca), magnesium (Mg), potassium (K), chromium (Cr), lead (Pb), zinc (Zn), nickel (Ni), manganese (Mn), and iron (Fe). All the samples met the World Health Organization (WHO) and Nigerian Specification for Drinking Water Quality (NSDWQ) specifications for TDS, EC, Na, Ca, Mg, Mn, Zn and Fe. Some water samples had moderately high concentrations of K, Ni, Cr and Pb, rendering them unsafe for consumption. The multi-pollution indices indicated significant contamination in the water samples. Similarly, the human health risk assessment revealed that prolonged consumption of water from the analyzed wells may pose significant health risks to the local population. The analysis of variance (ANOVA) revealed that pH and temperature varied significantly among the dumpsites while the Pearson’s correlation coefficient (PCC) revealed strong correlations for EC-TDS, Ni-K, Pb-Mn, and Ni-pH between the three dumpsites, suggesting similar hydrogeochemical processes from a common source. A Cd-Zn relationship was also observed for dumpsites in the three geological environments. Regular monitoring of heavy metal concentrations in groundwater near dumpsites is crucial to ensure the safety and quality of water resources for local communities.