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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

The aim of this study was to assess the heavy metal content of the dust generated by the Sagamu cement factory and its attendant health hazards on the immediate environment, especially on the inhabitants of the area. A total of 25 samples were collected and analyzed using inductively coupled plasma-optical emission spectrometry. Records of medical ailments associated with heavy metal toxicity were also compiled from the Obafemi Awolowo Teaching Hospital situated in the town. The results for some of the selected heavy metals showed the following pattern: limestone: Cd (n.d.-1.7 ppm), Pb (42-48 ppm), Cu (3.0-11 ppm), Zn (7.0-53 ppm) and Ni (3.0-8.0 ppm); shale: Cd (0.3-1.1 ppm), Pb (17-22 ppm), Cu (2.0-11 ppm), Zn (17-147 ppm) and Ni (3.0-18 ppm); dusts: Cd (0.5-0.7 ppm), Pb (32-52 ppm), Cu (2-16 ppm), Zn (5-152 ppm) and Ni (2-17 ppm); soils: Cd (0.5-1.1 ppm), Pb (28-49 ppm), Cu (22-35 ppm), Zn (43-69 ppm) and Ni (13.0-17 ppm). High levels of heavy metals were found in the rocks and soils. We propose that the high levels of metals in the dust and soil were acquired from the raw materials used by the cement factory and from active industrial discharge from this same factory. Medical records and the current health situation of the local residents in the study area reveal that there have been increases in the prevalence of diseases linked to heavy metal toxicity in the environment, especially those related to dust generation.

Provenance analysis serves to reconstruct the predepositional history of a sediment/sedimentary rock. This paper focuses on the reconstruction of the provenance and tectonic settings of the Niger delta clastic facies using geochemical approach. The main types of geochemical tests include major, trace, and rare earth element (REE) tests. Twenty-one samples of shales and sandstones units were purposely collected from a depth between 1160 and 11,480 m, grinded, pulverized, and sieved with a <75 μm. About 5 g was packed and sent to Acme analytical Laboratory Ltd., Vancouver, Canada. The analyses were carried out by both induced coupled plasma-mass spectrometry (ICP-MS) and induced coupled plasma-emission spectrometry (ICP-ES). Bulk-rock geochemistry of major oxides, trace elements, and rare earth elements was utilized for the provenance and tectonic setting determination. Based on the discrimination diagram for major oxides, the probable provenance of the south eastern Delta clastic sediments was mainly of the active continental margins. The bivariate plots of La versus Th, La/Y versus Sc/Cr, and Ti/Zr versus La/Sc and the trivariate plots of La-Th-Sc, Th-Sc-Zr/10, and Th-Co-Zr/10 are all plotted on the fields of active continental margin sediments which is consistent with the known actively opening of a failed arm of triple junction. The trace elements and REE analysis indicates that they are virtually Fe-rich, lithic/quartz arkosic sandstones. The normalizing factors used for the REE are Wakita chondrite. Their rare earth elements (REE) pattern displays high light REE/heavy REE (LREE/HREE) ratio, flat HREE, and a significant negative Eu anomaly which correlate well with the UCC and PAAS average composition. The source area may have contained felsic igneous rocks.

The Ramsar convention on wetlands defines wetlands as "areas of marsh, fen, peat-land or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or saline, including areas of marine water the depth of which at low tide does not exceed six meters". 1 Wetlands have unique characteristics that distinguish them from other water bodies or landforms. These include: hydrology (water level), soils (the soils are developed in watersaturated materials) and vegetation (plants adapted to wet conditions). As transitional areas between terrestrial and aquatic environments, wetlands serve as the depository of land-derived materials. 1 These materials include both beneficial and non-beneficial materials to flora and fauna well-being in the wetlands. 2 Sediment and soil contamination can be problematic on several levels, Background. Active cultivation of wetlands without consideration of the quality of the sediment is a common practice in the city of Lagos. Wetlands in several parts of the city have been cleared for growing vegetables and other crops. As a buffer for all surface runoff from the surrounding areas, wetlands are a depository for whatever contaminants are sourced from the catchments; hence the need to ascertain the quality of sediment on which edible crops are grown to determine suitability for agriculture. Methods. Wetland water samples were tested for pH levels, electrical conductivity, and total dissolved solids. Randomly selected core samples from one of the cultivated wetland areas located in the city center were taken to up to 8 cm in depth, then dried, recovered from the barrel and divided into groups of the following depths: 0-2 cm, 2-4 cm, 4-6 cm, and 6-8 cm. The dried and divided samples were subsequently sieved and analyzed for metal content using inductively coupled plasma mass spectrometry. Results for copper (Cu), lead (Pb), zinc (Zn), nickel (Ni), chromium (Cr) and vanadium (V) were geochemically evaluated. Results. The wetland water samples were found to be acidic, ranging from 5.9-6.4. The electrical conductivity was 430-500 µS/cm, and total dissolved solids, 280-320 mg/L. The metal content results (in mg/kg) for samples from 0-2, 2-4, 4-6 and 6-8 cm depths were: