Assessment of glyphosate and its metabolites' residue concentrations in cultured African Catfish offered for sale in selected markets in Ibadan, Oyo State, Nigeria.

Introduction: Glyphosate is a non-targeted organophosphate insecticide whose solubility and mobility in hydrophilic solvents enable its rapid leaching into the soil and subsequent contamination of ground and surface water and possible build-up in the aquatic food chain. Based on the public health importance of glyphosate in fish through consumption, it is crucial to determine the current residue concentration in culture Clarias gariepinus species. The aim of the present study is to evaluate glyphosate's residue concentrations and its metabolites in cultured African Catfish offered for sale in selected markets in Ibadan. Methods: A total of twenty-five (25) adult Clarias gariepinus (300 ± 50 g) were sourced from five (5) selected active fish markets (Ojoo, Iwo road, Eleyele, Challenge, and Apata) within the Ibadan metropolis. The collected fish tissue samples (liver, kidney, and spleen) were prepared for glyphosate residue concentration analysis using Liquid Chromatography (LC). Results: The results showed that glyphosate residues were recorded in all the seventy-five (75) fish tissue samples obtained from the selected fish markets in the Ibadan metropolis and all residue concentrations were above both the recommended Acceptable Daily Intake (ADI) of 1.0 mg/kg (1 × 10-3 mg/L) and Maximum Residue Limits (MRL) of 0.01 mg/kg (1 × 10-5 mg/L). Isopropylamine has the highest residue concentration followed by N-Phosphonomethyl and Aminomethylphosphonic Acid (AMPA), while N-Acetyl Glyphosate has the least residue concentration across the sampled markets. Discussion: The presence of residues of glyphosate and its metabolites in ready-to-eat fish calls for holistic, systematic, and effective risk management strategies towards monitoring pesticide/herbicide usage in aquaculture production and ensuring the provision of wholesome fish and fish products for the consumers.

How sawmill wastes impact surface water, sediment, macrobenthic invertebrates, and fish: a case study of the Lagos lagoon, Okobaba Area, South-western Nigeria.

The Okobaba area of the Lagos Lagoon, Nigeria, is characterised by sawmilling activities which are potential threats to resident aquatic organisms. This study was aimed at evaluating the effect of sawmilling activities on the environmental quality of the Lagos lagoon at Okobaba area, Lagos, Nigeria. Surface water, sediment, macrobenthic invertebrates, and fish species were sampled monthly from six stations for 3 months (July-September 2018). Relevant stakeholders were administered a cross-sectional questionnaire to determine their knowledge of the environmental effects of their activities. Environmental samples were analysed following standard methods. Descriptive and inferential statistics were performed using SPSS 20.0 and PAST 1.97. Results showed that surface water dissolved oxygen and chemical oxygen demand were significantly lower, while sediment total organic matter and nitrates were significantly higher at the test site compared to the reference site. A total of 389 macrobenthic invertebrates comprising eight species and two macrobenthic invertebrates comprising one species as well as 121 fishes comprising nine species and 70 fishes comprising nine (9) species were recorded at the reference and test sites respectively. About 46.3% of respondents alluded to improper waste disposal as the major cause of pollution at the test site among others, 66.7% responded that wastes were disposed of by burning among other disposal methods, and 66.6% agreed that the sawmilling activities contributed to reduction of aquatic animal population. We recommend urgent regulatory intervention to address the indiscriminate discharge of wastes and facilitate adequate environmental risk advocacy to sustain life below water (United Nations Sustainable Development Goal 14).

Micro- and Intermediate Filaments of the Testis of African Catfish (Clarias gariepinus) Treated with a Sub Lethal Dose of Carbendazim.

This study highlighted the effect of Carbendazim on the testicular micro and intermediate filaments adult male African catfish (Clarias gariepinus). Previous studies related to carbendazim toxicity in fish have been limited to mortality patterns and degree of sensitivity across species. Literature on actual pathology in fish  is scanty. The fish were exposed to a pre-determined sub-lethal concentration (1.4 mg/L) of Carbendazim for seven and fourteen days, 10 fish were  sedated by cold shock, and sacrificed on days seven and 14. Another untreated group (control) were sacrificed at the same periods. The testes were harvested and weighed.  Testicular actin microfilament, cytokeratin, desmin and vimentin intermediate filaments were determined using standard immunohistochemistry protocols. Variations in the intensity and pattern of immuno-expression of the testicular actin, cytokeratin, desmin and vimentin were significant in a phase dependent manner with day 14 being more pronounced. Immunohistochemical features of degenerated and necrotic germinal and Sertoli cells in the treated group, with loss of wire-mesh network which supported the mature germinal cells in the testicular lumen were also observed.   A sub-lethal dose of carbendazim exposure for either seven or 14 days, induced deliterous  changes in the testicular micro- and intermediate filaments, of the African catfish. This portends a reduction in the male reproductive potentials of the exposed species and resultant negative impact on production.

Perception and incidence of Buruli ulcer in Ogun State, South West Nigeria: intensive epidemiological survey and public health intervention recommended.

INTRODUCTION: Buruli ulcer (BU) is a highly ranked neglected tropical disease (NTD) of global health importance with increasing incidence in sub-Saharan Africa yet there is paucity of information on the epidemiology of BU in Nigeria. Incidentally, highly BU endemic Benin Republic shares proximity with Nigeria. This study was carried out to establish presence of BU and ascertain the level of BU perception among rural populace in Ogun State, south-west Nigeria. METHODS: Secondary data (2009-2012) on incidence of BU was collected from a reference hospital. A cross-sectional survey using structured questionnaire administered to rural people and healthcare practitioners was conducted in three purposively chosen Local Government Areas (LGAs) in Ogun State based on unpublished reports of BU presence. RESULTS: Data collected revealed 27 hospital confirmed BU cases between 2009-2012 across four LGAs (Obafemi Owode, Abeokuta North, Yewa North and Yewa South) while 14%(21/150) chronic ulcers (suspected to be BU) were discovered during the cross-sectional survey carried out in Odeda, Yewa South and North LGAs. Healthcare practitioners 63.6% (42/66) and 54.7% (82/150) rural people demonstrated poor level of BU perception respectively. CONCLUSION: This study provides evidence that BU exists in Ogun State and evaluates the poor perception that the affected rural populace has on the disease. This pilot study presents baseline information on BU in a rural setting in Ogun State South-west Nigeria hence the vital need for prompt public health involvement and further research on the epidemiology of BU.