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We have determined the heavy-metal status of the lower reaches of the New Calabar River in the Niger Delta region over a 40-km-long distance, and its impact on the development of catfish (juvenile Clarias gariepinus). The total mean concentrations of dissolved trace metals in the river were 0.01, 0.85, 0.56, 2.08, 0.05, 12.0, and 6.59 mg/l for Hg, Pb, Cd, Cu, Cr, Fe, and Zn, respectively. The accumulated concentration of trace metals in the muscles of different mature fish caught from the river were examined, and the results fell within the action levels adopted in most countries. To evaluate the contributions of trace metals to fisheries depletion, eggs of C. gariepinus were hatched in dilution water spiked with the total mean metal levels determined in the river water. Our results indicate substantive inhibition of egg hatch even at very low concentrations of the majority of the trace metals studied, with mortality rates well above 50% after 216 h of exposure (Table 5). These findings suggest that trace metals (except for Zn), even at very low concentrations, negatively affect fish hatch and fry rearing, implying that aquatic milieus contaminated by trace metals are not suitable as nursery grounds for fish cultures.

Proximate analysis and phytochemical screening of Triclisia subcordata Oliv leaf were investigated using standard analytical methods. Results of the proximate analysis showed contents for moisture (79.28±2.32%), ash (1.91±0.21%), crude fibre (1.83±0.13%), lipid (1.81±0.16%), crude protein (8.32±1.20%) and carbohydrate (6.91±0.74%). Phytochemical screening showed the presence of all six metabolites studied but at different concentrations. Saponin and flavonoids > alkaloids > phenol, tannin and cyanogenic glycoside. Tannins, saponins, alkaloids, flavonoids, cyanogenic glycosides and phenol gave 0.01±0.00%, 5.81±0.23%, 2.32±0.13%, 6.01±0.36%, 0.20±0.00% and 0.03±0.00%. Given observed high contents of moisture, flavonoids and saponins, moderate amounts of alkaloids and low contents of lipid, cyanogenic glycosides, tannins and phenols in Triclisia subcordata Oliv leaf, this study rationalises the medicinal use of the plant, and unveils its potential as a source of micronutrients.

ABSTRACT:The levels of some trace metals (Fe, Zn, Cu, Ni, Cd) were quantitatively determined in raw and heat processed staple food cultivars (yam, cassava, cocoyam and maize) from oil producing areas of part of the Niger Delta and compared with a non-oil producing area of Ebonyi State as control. The survey was conducted to evaluate the role of foods as exogenous source of these metals among the inhabitants. The data showed that metal levels in all the raw staple foods from oil producing areas were significantly higher at (p<0.05) than those from non-oil producing areas. However, lead levels of all the raw staple foods in all the studied areas were below detectable levels. Exceedingly higher levels of these metals characterized the raw staple food cultivars from oil producing areas than those from non-oil producing area and on heat treatment the levels were reduced. These high levels are indicative of extensive pollution in these areas understudied suggesting possible health risks in consumption of food cultivars from such areas. @JASEM

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Aim: To ascertain the effects of boiling and fermentation on the physicochemical properties, fatty acid, mineral and vitamin composition of Hibiscus sabdariffa (HS) seeds. Study Design: Completely randomized design Place and Duration of Study: Rivers and Anambra states, Nigeria, between February and September, 2018. Methodology: Two portions of 200 grams of HS seeds each were subjected to boiling and fermentation. The three samples were designated HSR, HSB and HSF for raw, boiled and fermented HS seeds respectively. Standard methods were used in determining the physicochemical properties and micronutrient composition, while fatty acid constituents were identified using a gas chromatography. Results: The acid, free fatty acid, peroxidase values and specific gravity were significantly increased (p<0.05), while iodine value was significantly reduced (p<0.05) after boiling and fermentation. Saponification value showed a mixed trend, while refractive index was not significantly (p>0.05) altered. Lauric (5.51–33.79%), palmitic (27.23–30.87%) and myristic (12.69–35.00%) acids were the predominant saturated fatty acids in HSR, HSB and HSF samples respectively. Oleic, linoleic, alpha-linolenic and arachidonic acids were the unsaturated fatty acids present in the samples. Boiling increased oleic acid level, while fermentation caused a drastic reduction (>90%) in its amount. Linoleic acid level improved up to 43% after fermentation. Magnesium, iron and sodium amounts significantly (p<0.05) reduced after boiling and fermentation, while zinc, calcium and molybdenum levels were significantly (p<0.05) improved after boiling. Na/K ratios for all the samples were greater than 0.60, while Ca/Mg values ranged between 0.82 and 3.46, below the recommended value (1.0). Vitamins B1, B3, B12 and D were significantly reduced (p<0.05) after boiling and fermentation, while fermentation significantly increased (p<0.05) vitamins B2, A, E and K levels. Conclusion: HS seeds were shown to possess good physicochemical properties that can enhance its utility in the industry. Boiling and fermentation maximized the usefulness of HS seeds as quality nutritional plant.

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