Background. Increased growth of industrial activities, especially in urban centers, is one of the main sources of toxic substances in Nigeria. The level of these impacts is not well known. Soil and sediment samples from one such industrial area were examined for their mineralogical composition and heavy metals contents in order to assess the level of contamination and potential ecological risk status. Methods. Mineralogical composition of the media and their heavy metals concentrations were determined using X-ray diffractometry and inductively coupled plasma-mass spectrometry methods, respectively. Ecological risk assessment was carried out using single (contamination factor, geo-accumulation index, enrichment factor) and multi-elemental (contamination degree, pollution index and modified pollution index) standard indices. Results. The average heavy metal concentrations in soils and sediments followed the order magnesium (Mn) > chromium (Cr) > lead (Pb) > copper (Cu) > cadmium (Cd) > cobalt (Co) > nickel ...

Background. Metal recycling factories (MRFs) have developed rapidly in Nigeria as recycling policies have been increasingly embraced. These MRFs are point sources for introducing potentially toxic elements (PTEs) into environmental media. Objectives. The aim of this study was to determine the constituents (elemental and mineralogy) of the wastes (slag and particulate matter, (PM)) and soils around the MRFs and to determine the level of pollution within the area. Methods. Sixty samples (30 slag samples, 15 soil samples and 15 PM samples) were collected for this study. The soils, slag and PM samples were analyzed for elemental constituents using inductively coupled plasma optical emission spectrometry. Mineralogy of the PM was determined using scanning electron microscope-energy dispersive spectroscopy (SEM-EDS), and soil mineralogy was determined by an X-ray diffractometer (XRD). Results. The results of the soil analyses revealed the following concentrations for the selected metals in mg/kg include lead (P...

The harmful health effect of suspended particulate matter (PM₁₀) is mostly associated with its mass concentrations and chemical compositions. Therefore, this study focuses on the determination of the particulate matter (PM₁₀) concentrations and their potentially toxic elements (PTEs) composition from different road networks in Ibadan southwestern, Nigeria. In addition, human health risk assessment was estimated from the PTE data. The PM₁₀ samples were collected from different road networks such as national highway roads (NHR), inner-city major roads (ICR), and remote roads (RRD) in Ibadan, Nigeria. The sampling was carried out with a high-volume air sampler (model #15000 manufactured by Science Resource, Walboro, USA) with a PM₁₀ cut-off on a Whatman cellulose filter during the harmattan period. The PM₁₀ concentrations and PTEs compositions (Al, Ba, Cd, Cu, Fe, La, Mo, Mn, Ni, Pb, V, and Zn) were determined by gravimetry and inductively coupled plasma-optical emission spectrometry (ICP-OES) methods (VISTA-MPX manufactured by Varian Incorporation), respectively. The PM₁₀ concentrations in all three road networks were more than 3 folds higher than World Health Organization (WHO), United State Environmental Protection Agency (USEPA), and United Kingdom Environmental Protection Agency (UKEPA) standards (50 µg/m³) for 24 h. The maximum average contents of Ba, Cd, Cu, La, Mn, Pb, and V, were observed at NHR, while that of Al, Fe, Mo, and Zn, were found at ICR. The principal component analysis (PCA) showed that PC1 (Ba, Cd, Cu, La, Mo, Pb, and V) and PC4 (Zn) were characterised by elemental markers of both exhaust emission and non-exhaust emissions, while PC2 (Mn) and PC3 (Al, Fe) were characterised by crustal elements. The Enrichment factor (EF) analysis classified all the PTEs as moderately to very highly enriched, especially in NHR and ICR, except Al, Fe, and to some extent Mn. Both the maximum and average hazard quotient (HQ) levels of Cd, Cu, Mn, Pb, and Zn were < 1, which was within the permissible level. Also, the carcinogenic risk (CR) was also within the permissible limit.