Relationship between extreme daily rainfall and maximum daily river discharge within Lagos metropolis

Many research works emphasized on rainfall pattern and urban flooding while others examined the relationship between extreme rainfall and its implication for flood frequency with little attempt to establish relationship between extreme rainfall and maximum river discharge. This study therefore, draws interconnection between extreme daily rainfall and maximum daily river discharge within Lagos metropolis. Data on rainfall were collected from Ikeja and Lagos Roof weather stations within the Yewa Basin in Lagos. Also, data on river discharge for Yewa River were obtained from Ogun-Oshun River Basin Development Authority, Abeokuta. Pearson Product Moment Correlation Coefficient (PPMC) was employed to assess the relationship between extreme daily rainfall and maximum daily river discharge at 95% confidence level. Analysis of Variance (ANOVA) employed was used to test for the variability in the means of extreme daily rainfall events across the two weather stations. The result showed that there is a significant relationship between extreme daily rainfall events and maximum daily river discharge for Ikeja station (tvalue = 2.60, Cv= 2.18, P≤0.05) while no significant relationship was shown in Lagos Roof (tvalue = 1.60, Cv= 2.18, P≥0.05). It was also revealed that that there are no significant differences in the mean values of extreme daily rainfall across the stations (F130=2.086, P≥0.05).Therefore, this work has been able to show that the relationship between extreme rainfall and maximum river discharge is not always significant due to several factors such as distance from the sea (continentally) and variation in rainfall across the weather stations.Keywords: Extreme Rainfall, Maximum River Discharge, Ogun-Osun, Flood Frequenc

Tax Structure and Economic Growth in Nigeria

The development of endogenous growth theory has opened an avenue through which the effects of taxation on economic growth can be explored. Taxes are the importance aspects of government revenue and they also act as means of transferring resources from the private sector to the public sector. Explicit modeling of the individual decisions that contribute to growth allows the analysis of tax incidence and the prediction of growth effects. This paper reviews the theoretical and empirical evidence to assess whether a consensus arises as to how taxation affects the rate of economy growth. It is shown that the theoretical models isolate a number of channels through which taxation can affect growth and that these effects may be very substantial. Although there are empirical difficulties, the empirical evidences point very strongly to the conclusion that the tax effect is very weak. Keywords: Tax, Structure, Growth, Economic, Nigeria.

Hydrogeological deep percolation modelling of groundwater recharge in Voinjama Region, Liberia

Indirect physical methods of assess groundwater recharge rely on the measurement or estimation of soil physical parameters, which along with soil physical principles; can be used to estimate the potential or actual recharge. However, the deep percolation method uses a daily water- budget approach to simulate deep percolation. In this method, the model computes daily fluxes of water into and out of a volume extending from the top of foliage to the bottom of the root zone and accounts for changes in water content. In most environments, deep percolation is destined to recharge the saturated systems that are tapped by wells. Deep percolation technique was deployed to determine the rate of ground water recharge in the Voinjama region of Liberia, and also establish points of lineaments where wells can be dug for water supply. The perimeter of the hypothesized basin is about 28.9km while the length of the thalweg of the mainstream is about 11km. the average width of the basin area is 5.9km while the circumference of the equivalent circular area is 25.33km and compactness coefficient (R) of the basin is computed at 1.14. The elongation ratio (Er) is computed at 0.73km. The diurnal recharge computed from Deep Percolation was 6712.21 cm3 /km2 per annum. In conclusion, this study aids the restoration of water supply system destroyed during the war periods emphasizing the abundant water in the hydrological system and viable ground water recharge adequate for exploitation in a near uniform geology. Several faults and crevices scattered abroad the area were recorded indicating good lineament distribution and abundant aquifer recharge.Keywords: Hydrogeology, Deep Percolation Method, Groundwater, Recharg

Heavy metals and sensory evaluation of canned tuna fish

In this study, two heavy metals in canned tuna fish were determined after digestion by the AOAC methods. Mercury and Cadmium levels in canned tuna fish were determined by flame atomic absorption photometry. The results of this study indicate that canned tuna fish imported into the country have concentrations well below the petmissible FAO/WHO levels for these toxic metals. Their contribution to the body burden can therefore be considered negligible and the fish seem to be safe for human consumption. For the sensory evaluation, tuna flakes in vegetable oil (Starkist) from Ghana and light meat tuna chunks in sunflower oil (John West) from Thailand were the most preferred while tuna flakes in brine (John West) from Thailand is the least preferred

Mercury content of some canned seafood collected from Nigerian retail markets

Twenty samples of canned seafood consisting of tuna, mackerel, sardines, prawn and shrimp were collected from retail operations in Victoria Island, Lagos, Nigeria. Mercury content in these canned seafood were determined after digestion by the Association of Official Analytical Chemists methods. The mercury contents for all the canned seafood products have concentrations well below the permissible EU levels for this toxic metal. Their contribution to the body burden can therefore be considered negligible and the canned seafood products seem to be safe for human consumption

Effects of preservatives on the proximate and sensory analysis of smoked-dried Clarias gariepinus during ambient storage

The effect of food grade chemical and natural preservatives on the proximate and sensory analysis of smoked catfish Clarias gariepinus during six weeks ambient storage were determined. Eleven pre-smoking treatments were applied: 25% sodium chloride (NaCl) and 1% ascorbic acid for Iht 25% NaCI and 1% ascorbic acid for 30mins; 3% sodium lactate for 30mins; 3% sodium lactate and ginger (Zingiber officinale) extract for 30mins; 5% sorbic acid for 3Omins; 5% sorbic acid for 1h; 3% sodium lactate and Tetrapleura tetraptera extract for 30mins; 3% sodium lactate and Ethiopian pepper (Xylopia aethiopica) extract for 30mins; Z. officinale extract for 30mins; X aethiopica extract for 30mins and T. tetraptera extract for 30mins. The samples were smoked, cooled and packed for analysis at 0, 2, 4 and 6 weeks of ambient storage. The values of the proximate analysis ranged between 13.0-19.5%, 3.5-5.5%, 12.3-17.6% and 58.4-68.7% for moisture, ash, lipid and protein respectively. There were no significant change of proximate composition and sensory evaluation (p< 0.05) within each treatment groups during the 6 weeks storage without refrigeratio

Pulverized Calcined Clay and Carbide Waste as Alternative Binder in Concrete and Mortar Applications for Sustainable Construction

Portland cement (PC) based concrete is the world’s most consumed man-made material and this consequently puts lots of demand on cement as a binder. The CO2 gas emission during cement clinker production has placed this important material into non-environmental-friendly classification with quest for greener alternatives being on the rise. A recent study showed combination of Pulverized Calcined Clay (PCC) and Calcium Carbide Waste (CCW) as possible alternative for total PC replacement with resulting appreciable mortar strength but delayed setting times and lower strength than PC mortars. This paper reports on effects of PCC-CCW as alternative binder on strength properties of mortars. The mortar mixes had superplasticizers added to reduce water/binder ratio while the CCW was treated to reduce impurities with a view to improving the strength development and a bid to mitigate the observed setbacks of earlier study. The pozzolanic activity indices of the PCC was determined via X-Ray Fluorescence(XRF) and strength determination (strength activity index). The PCC was combined with Purified CCW to determine the binder’s strengths at varying PCC:CCW replacements to determine the prescribed mix combination for optimum strength. Improved optimised mortar strength of 13.11MPa was achieved compared to 11.89MPa in the previous stud

Aflatoxin levels in selected fish feedstuffs and fish feeds sold Inoko Oba Area of Lagos State, Nigeria

This study determined the level of aflatoxin contamination in some fish feeds and fish feed ingredients sold in Lagos. Nigeria. Sixty-two (62) samples: fish feed (12), fishmeal (10), groundnut cake (10), soybeans meal (10), wheat offal (10) and crushed maize (10) were randomly purchased from an agro feeds market inOko oba area of Lagos. Aflatoxin analysis was carried out using the Enzyme-Linked Immunosorbent Assay (ELISA) method-RIDASCREEN FAST Aflatoxin Total. Aflatoxin contamination was detected in approximately 50% of the fish feeds, while 70 – 100% of the feedstuffs were highly contaminated. The aflatoxin concentrations in the samples ranged from 1.85 - &gt; 45μg/Kg. There were no significant difference (p&lt;0.05) in the aflatoxinconcentration in the fish feeds, fishmeal, soybeans meal and wheat offal, but these concentrations were significantly (p&lt;0.05) lower than those of groundnut cake and crushed maize. The moisture content of the samples was not significantly different (p&gt;0.05) ranging from 1.86 to 2.44%. Most of the feedstuffs were highly contaminated. There is therefore a need to create more awareness among stakeholders in the aquaculture industry on the need to source for good quality feedstuffs and the inherent dangers in the use of aflatoxin-contaminated fish feeds and feedstuffs.Keywords: Aquaculture, feed safety, fungi, contaminatio

Assessment of health risks from potassium bromate and trace metals in bread consumption in Ado Ekiti, Southwest, Nigeria

Introduction: Bread, a staple food consumed by a large portion of the population worldwide, including Nigeria, has emerged as one of the most popular quick meal options. The excessive intake of potassium bromate and trace metals in bread has been identified as detrimental to human health due to its heightened propensity to induce cancer in human. Objective: The current study assessed the exposure to potassium bromate (KBrO3) and trace metals through bread consumption, as well as the associated risks to dietary habits among Ado Ekiti, Southwest Nigeria residents. Bread varieties commonly consumed in Ado Ekiti were randomly chosen from local bakeries. These bread samples were then analyzed in the laboratory using an Atomic Absorption Spectrophotometer to determine the levels of trace metals, including lead (Pb), manganese (Mn), nickel (Ni), chromium (Cr), zinc (Zn), cadmium (Cd), and cobalt (Co), as well as potassium bromate concentrations. Results: The findings revealed that cobalt (Co) had the highest mean concentration (29.35±3.59 mg.kg−1), whereas lead (Pb) exhibited the lowest mean concentration (0.06±0.02 mg.kg−1). The sequence of trace metal levels was Co > Cd > Zn > Ni > Mn > Cr > Pb. All trace metal concentrations exceeded the standards set by FAO/WHO. Regarding potassium bromate content, it ranged from 0.01 mg.kg−1 to 0.06 mg.kg−1, surpassing the maximum permissible limits of 0.02 mg.kg−1 set by the Food and Drug Administration.Although the chronic hazard quotient among adults and children was low, the hazard ratio ranged from 11 to 9 among adults and from 14 to 9 among children, suggesting the potential for carcinogenic effects with repeated consumption. Based on the hazard ratios, the estimated chances of developing cancer from daily consumption of bread samples were approximately 14 in 1,000,000, 86 in 1,000,000, 71 in 1,000,000, and 40 in 1,000,000, respectively, for the adult population, and about 20 in 1,000,000, 11 in 1,000,000, 90 in 1,000,000, and 56 in 1,000,000 for the children population. Conclusion: The study showed that trace metals Pb, Mn, Ni, Cr, Zn, Cd and Co concentrations were higher than the FAO/WHO permissible limits. The concentration of potassium bromate in all the sorted bread samples exceeded the maximum acceptable limits except one. Though chronic hazard quotient among adults and children was low, the hazard ratio among the adult and children population was high, signifying possible cancer risks when continually consumed. These findings underscore the importance of stringent oversight by Nigerian regulatory authorities over using potassium bromate as an ingredient in bakeries