Nutrients: trace metals, micronutrients, oestrogen and B-vitamin content of Osun River: A River that runs southwestern Nigeria into the Atlantic Gulf of Guinea

Abstract

Osun-Osogbo Grove has a long history of healing and therapeutic claims by adherent believers, in spite of advancement in medicine. Scientists made attempts at investigating the biodiversity of the Grove, till date, there has not been convergence point between science and these indigenous beliefs. This study identified the presence of therapeutic agents in the water of Osun-Osogbo River, paying attention to at least six parameters; vitamin, phosphate, nitrate, amino acid, hormone and trace metal. Water samples were taken from two different sites during pre, during and post raining sessions (April 2017 - September 2019) were analysed using High Performance Liquid Chromatography (HPLC), Gas Chromatography Mass Spectroscopy (GC-MS) and Atomic Absorption Spectrometer (AAS). Trace metal analysis revealed an average of 0.009-0.079 mg/Kg Zinc from site one and lower in site two. The mean value of manganese at both sites was virtually the same at 0.018-0.313 mg/kg, aluminum content was 0.045-0.179mg/Kg at site one, 0.050-0.192mg/kg at site two, cobalt was 0.024 mg/kg at site one, 0.026 mg/kg at site two while nickel was 0.006 mg/kg and 0.004 mg/kg for site one and two respectively. HPLC analysis shows mean Methionine content at both sites is higher than the FDA (56.6 ug/mL); site one had 74.41 ug/mL while site two had 57.11 ug/mL The mean values of two water-soluble vitamins; Thiamine (B1) was 3.758 mg/Kg and 2.355 mg/Kg while Pyridoxine (B6) was 0.108 mg/Kg and 0.072 mg/Kg at site one and two. GCMS analysis of steroidal content revealed values below lowest observed effect level (LOEL), testosterone (4.8 ng/L) and estrogen (2.4 ng/L) were still elevated while ethinylestradiol and estriol were ≥1.5 ng/L. Summarily, site one the major part for spiritual activities showed higher essential nutrient contents than site two which support the enrichment and potential therapeutic properties of the Osun river water. However, further scientific research is required to ensure that these therapeutic potentials supersede the toxicological effect.