Clay Minerals as Indicator of Phosphatogenesis: A Case Study of Sokoto Basin, Northwestern Nigeria

Phosphate deposits which occur in the Sokoto Basin of northwestern Nigeria is more pronounced in the shales of Dange Formation which recorded value ranges of 32- 36% P2O5. Minor occurrences were documented in shale of Dukamaje Formation and the limestone of Kalambaina Formation. However, non phosphatic siltstone, marl, shale and sandstone also occur. Clay mineral evaluation of the phosphatic and non phosphatic units was undertaken in order to study their relationship with phosphatogenesis. Result of analysis shows that the clay mineral distribution in the phosphate bearing sediments and non phosphatic units are consistently different. Kaolinite and hydrargillites are associated with phosphate bearing sediments whereas montmorillonite is typical of non phosphatic ones. The study of clay mineral distribution appears to be a good tool in phosphate exploration in an epicontinental inland basins. Keywords: Phosphatogenesis, Clay mineral, Sokoto Basin, Kaolinite, Montmorillonite, Paleocen

APPLICATION OF ENZYME-LINKED IMMUNOSORBENT ASSAY FOR AFLATOXIN CONTENT EVALUATION OF DIFFERENT POWDERED MILK AVALABLE IN ANAMBRA STATE, NIGERIA

The application of enzyme-link immunosorbent assay for aflatoxin contamination of 20 different powdered milk samples consumed within Anambra State, Nigeria was carried out primarily to ascertain their health implications. The samples were subjected to Ridascreen ELISA competitive enzyme immunoassay for the quantitative determination of aflatoxins in the milk. All the reagents required for the enzyme immunoassay including statndards were contained in the test kit used. Preparatory samples stages were grinding, extraction, filtration/centrifugation followed by acid mixture digestion process with tablet of selenium catalyst. The proximate analyses of the samples were done via AOAC standard procedures. The results revealed relatively low moisture contents with a range of 1.64 to 4.72%, with sample T recording highest value of 4.72% . The highest value of ash content was observed for sample D ( 6.57%) while sample R had lowest value of 0.85%. The lowest amount of crude fat was recorded by sample F (2.60%) as against high value of 21.33% for sample B.  Crude protein showed least amount in samples A (20.19%) with the highest amount found in sample H (23.67%). The quantification of aflatoxins in the 20 powdered milk samples using ELIZA method revealed relatively low concentration of aflatoxins in the samples and the trend observed had a range of 0.36ppm (sample B) to 0.81ppm (sample F). The average aflatoxin concentration was estimated to be 0.61ppm. Samples C, E and F had mean level of aflatoxin recorded as 0.71ppm while the mean amount implicated for samples A, B, G and K was 0.51ppm. Conclusively, the results of the proximate analysis of the milk samples revealed appreciable occurrence of crude protein and relatively low amount of aflatoxins. The level of aflatoxins in all the samples was found to occur below National Regulatory threshold value of 4ppm, hence all the samples analyzed can be adjudged to be safe for consumption with little precautionary measures for hygiene and preservation