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 (Ni), with corresponding values for soils and sediments of 324.3, 79.9, 66.1, 40.7, 14.3, 9.1, 6.8 mg kg−1 and 266.8, 78.6, 40.6, 39.8, 12.9, 8.4, 4.6 mg kg−1, respectively. Principal component (PC) analysis of the results indicated three main sources of metals (industrial, vehicular activities and geogenic input). Evaluated contamination factor (Cf), enrichment factor (Ef) and geo-accumulation index (Igeo) revealed very high contamination for Pb, Cd and Cu in all of the samples, with calculated pollution index (PI) and modified pollution index (MPI) revealing that all the samples were severely polluted. Calculated potential ecological risk factor (ERi) within the industrial area demonstrated a strong potential ecological risk for Cd, Pb and Cu.Conclusions.Activities in the industrial area have affected the quality of the analyzed environmental media, with possible detrimental health consequences. Regular environmental monitoring of the industrial area and the formulation of appropriate policies that support reduction of contamination are strongly recommended. However, due to the limitations of comparing site samples with a single control sample in this work, further study is recommended to compliment this preliminary study.Competing Interests.The authors declare no competing financial interests

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 (Pb) (21.0–2399.0), zinc (Zn) (56.0–4188.0), copper (Cu) (10.0–1470.0), nickel (Ni) (6.0–215.0), chromium (Cr) (921.0–1737.0) and cadmium (Cd) (below detectable limit (Bdl)-18.1). For the slags the results were Pb (68.0–.333.0), Zn (1364.0–3062), Cu (119.0–1470.0), Ni (12.0–675.0), Cr (297–1737) and Cd (Bdl-15.8). The results in μg/g for the metal analysis in PM were Pb (4.6–160.0), Zn (18.0–471.0), Cu (2.5–11.0), Ni (0.8–4.2), and Cr (2.5–11.0), while Cd was undetected. The slags are currently utilized for filling the foundations of buildings and roads, providing additional pathways for the introduction of PTEs into the environment from the suspended materials generated from mechanical breakdown of the slags.Conclusions.The MRFs were found to have impacted the quality of environmental media through the introduction of PTEs, impairing soil quality, in addition to PM, which can have detrimental health consequences. Further studies on the health implications of these pollutants and their impacts on human health are needed.Competing Interests.The authors declare no competing financial interests

Background. Rare earth element (REE) composition of atmospheric dust has recently been used to trace potential sources of dust pollution. Objective. The present study aimed to determine the sources of atmospheric pollution in the study area using REE patterns and determine their level of pollution. Methods. Twenty-five (25) atmospheric dust samples were collected in the study area, with five samples each from an industrial area, traffic area, dumpsite area, residential area and remote area in Ibadan, southwestern Nigeria. In addition, five (5) topsoil and two (2) rock samples (granite gneiss) were collected for comparison. Concentrations of REE were determined by inductively coupled plasma mass spectrometry (ICP-MS). Results. The ratio of lanthanum/cerium (La/Ce), especially in some locations in industrial area (1.5), traffic area (1.5) and to some extent dumpsite area (1.1) was higher than in soil (0.2), upper continental crust (0.5) and the minimum value of fluid catalytic crackers (1.0). Generally, the respective average values of the ratios of La/praseodymium (Pr), La/neodymium (Nd) and La/samarium (Sm) in industrial area (32.1, 7.8 and 52.6) and traffic area (14.9, 4.4 and 26.8) were higher than their respective averages in soil (4.4, 1.1 and 6.2), rock (5.7, 1.9 and 14.1), upper continental crust (4.4, 1.1 and 6.6) and the minimum value in fluid catalytic crackers (5.8, 3.7 and 37.0). Meanwhile, their corresponding value in the dumpsite area, residential area and remote area were lower or similar to the geological background levels. Discussion. The contamination factors of REEs in the atmospheric dust of the industrial area and traffic area were classified as heavily contaminated, especially with light lanthanoid elements in REE. The degree of contamination of REEs in the atmospheric dust of industrial area (30.9) and traffic area (18.8) fell within the considerable contamination category. The high values of the light lanthanoid ratio and the contamination indices were attributed to their emission from the fired-power plant and vehicular exhaust. Conclusions. Most of the composition of the atmospheric dust was sourced from the local geology of the study area as observed in the residential area and remote area, while the contamination in the industrial area and traffic area was attributed to human activities. Competing Interests. The authors declare no competing financial interests.

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Cemeteries have been identified as a possible source of groundwater and environmental pollution. This may be due to wrong siting of cemeteries, poor soil selection and very thin vadose zone. Over the years, most communities around Osun State experience a number of communicable diseases like dysentery, diarrhea and typhoid, especially after episodes of flash floods. Therefore, this study was carried out to audit the impact of burial practices on the immediate environment viz-a-viz their interaction with both surface and groundwater which forms the main source of potable water for the communities. Method of approach include; assessing possible water contamination, studying the vadose hydrological characteristics as well as studying the geotechnical properties of soils within the vadose zone. Water samples from the vicinity of both cemeteries shows probable contamination with an average pH of 6.19 for Ede and 6.57 for Iragbiji, EC with an average 480μS for Ede and 1210μS for Iragbiji. Biological constituents found within the area include; enterobacteriaceae (salmonella spp., serratia spp., proteus spp., shigella spp.), suggesting likely contamination of both surface and groundwater around the vicinity of the cemeteries. Most cations and anions analysed for (Mg2+, NO3-, SO42-, and PO43-) comply with the WHO standards based on their maximum permissible limits (MPL). Geotechnical investigations revealed that soils within the study areas are largely unsuitable for a standard cemetery due to their high moisture content, poor grading characteristics, low compaction value, poor hydraulic characteristics and shallow water level. The study concluded that cemeteries from both towns have a negative impact on their immediate environment due to poor selection of soil materials (porous and permeable sandy soil) as reflected in the quality of surface and groundwater.