Information on the occurrence of pharmaceuticals in the environment of Nigeria is limited, only a single publication previously on pharmaceutical occurrence in the environment of Nigeria, which measured general estrogen levels in Enugu, South-East Nigeria. In order to establish a first overview, surface water samples from six locations as well as ten sewage sludge samples from waste water treatment plants were analysed for a range of different pharmaceuticals, including antibiotics, estrogens, and lipid-lowering drugs. The results of this monitoring campaign were evaluated in comparison to published measured environmental concentrations in Africa and worldwide. In surface water samples, 12 of 37 pharmaceutical substances were detected at concentrations ranging from Limits of Detection (LOD) up to 8.84 µg/l. Four of these pharmaceuticals were found at concentrations exceeding ecotoxicological predicted no-effect concentrations (PNEC). In industrial, domestic, and hospital sewage sludge, nine different pharmaceutical substances were detected with the NSAID diclofenac present in all samples at concentrations of up to 1100 µg/kg dry weight, exceeding the highest measured concentration of 560 µg/ kg reported in sludge samples worldwide. This study proves the presence of several pharmaceuticals at relevant concentrations in the environmental matrices studied. Further, more comprehensive monitoring campaigns, especially in locations with high population density and low dilution of treated or untreated waste water in receiving streams are recommended.

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Abstract. Several toxicological studies into the effects of aquatic pollutants on the liver of teleost fish exist in literature. The focus on the liver in these studies is predicated on its central nature in the scheme of biotransformation and excretion of xenobiotics following exposure in polluted water bodies. As a consequence of the latter primary role of the liver in these processes it is regarded as a predilective site for the sub lethal effects of xenobiotics on the organism usually detectable at histological level. Hepatic histopathology recorded in livers from feral populations of the brackish water catfish Chrysichthys nigrodigitatus from locations on the Lagos lagoon complex with significant anthropogenic inputs from denizen populations and industries are presented. Liver sections from sixty specimens from two locations on the Lagos lagoon complex (Badagry lagoon: 6 0 24'N, 2 0 56'E; and Lagos lagoon: 6 0 29'N, 3 0 22'E) were analysed. Observed pathologies included hydropic degeneration (58%), portal / sinusoidal congestion (33%), hepatic necrosis (26%), hemosiderosis (12%) and foci of cellular alterations (FCA's). No obvious oncologic features were observed; the presence of the hydropic Vacuolation lesion was taken as prelude to the development of neoplasms and discussed as such.

Microplastics are a fast-emerging group of contaminants. Their worldwide occurrence in water, sediment, and aquatic fauna raises questions and concerns as to their probable effects on aquatic life and ecology. This study investigates for the first time presence, abundance, and types of microplastics in water and sediment from a lagoon bordering the large urban agglomeration of Lagos in Nigeria, and renders additional information about the sediment composition. Water and sediment samples were collected from four locations in the Lagos Lagoon and a tributary. The abundance and distribution of microplastics in four range classes were determined for the sampled locations. Plastic particles were counted using digital microscopy, and identified with Fourier Transform-Infrared Spectroscopy (FTIR) and pyrolysis Gas Chromatography–Mass Spectrometry (GC-MS). The abundance of microplastics ranged from 310–2319 particles/kg in sediment, and 139–303 particles/L in water. The large discrepancy in the sediments can be explained by sediment characteristics as more microplastics were detected in the fine-grained sediments of Makoko. Fibres were the predominant shape found in all samples followed by fragments and few films. Fibres were more abundant in water (92.6%) than in sediments (32.5%), while more fragments and foils occurred in sediments. The most commonly used polymers polypropylene and polyethylene were also the most detected ones in both matrices. Compared to other studies in Nigeria, our findings especially in the coarser sediments were lower while the fine-grained site revealed similar results.

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