The mineral (Li, Na, K, Ca, Mg, Fe, Cu, Mn, Zn and Pb) composition of each of five species of fish, including Sarotherodon galilaues, Cyprinus carpio, Clarias gariepinus, Sardinella spp. and Labeo spp. Was determined in samples previously dried, either by traditional smoking method, or in laboratory oven, to gain knowledge of the quality and acceptability of the smoked products. The samples were brought from markets in Minna metropolis, Niger State of Nigeria. Portions of the meals of whole fish were digested in a nitric acid-hydrogen peroxideperechloric acid (3:11) mixture and the digests were analysed spectrophotometrically. The concentration of lead was lowest in both smoked and oven-dried specimens with mean values ranging from 0.46 to 1.16mg/kg and 0.54 to 0.76mg/kg, respectively, while calcium with ranges of 592.98 to 7553.55mg/kg and 498.65 to 6460.85mg/kg was highest. Comparative studies showed that no significant differences existed between the mineral contents of the samples from the two drying methods, except in the few cases of lithium in S. galilaeus, zinc in C. gariepinus, copper and manganese in both Cyprinus carpio, and Sardinell spp, and lead in S. galilaues. Nonetheless, the smoked samples were consistently richer in their mineral content, suggesting the need for chemical examination of products of this drying method. @JASEM

Five substituted tridentate salicylaldimines, (E)-2-((2-hydroxybenzylidene)amino)phenol, (E)-2-(((2-hydroxyphenyl)imino)methyl)-4-nitrophenol, (E)-4-chloro-2-(((2-hydroxyphenyl)imino)methyl) phenol, (E)-2-(((2-hydroxyphenyl)imino)methyl)-4-methoxyphenol, (E)-4-bromo-2-(((2-hydroxy-phenyl)imino)methyl)-6-methoxyphenol were synthesised and characterised by elemental analysis, IR, UV and NMR (1H and 13C). They were screened against some multi-drug resistance Gram-positive (Streptococcus agalactiae and Staphylococcus aureus), and Gram-negative (Escherichia coli, Klebsiella pneumonia, Proteus mirabilis, Pseudomonas aeruginosa and Salmonella typhimurium) organisms by the agar-well diffusion method. The total antioxidant capacities of the salicylaldimines were determined by the phosphomolybdenum assay. Their antibacterial and antioxidant activities were screened to understand the substituents effects. The result showed that the methoxy-substituted compound exhibited the highest antibacterial and antioxidant activities while the nitro-substituted compound exhibited the least activities. This implies that the electron-donating group of the compound increases its antibacterial and antioxidant activities. The one-way analysis of variance was performed with MINITAB 17 at 95% confidence level.

The analysis of total organic carbon (TOC) by the American Public Health Association (APHA) closed-tube reflux colorimetric method requires potassium dichromate (KCrO), silver sulfate (AgSO), and mercury (HgSO) sulfate in addition to large volumes of both reagents and samples. The method relies on the release of oxygen from dichromate on heating which is consumed by carbon associated with organic compounds. The method risks environmental pollution by discharging large amounts of chromium (VI) and silver and mercury sulfates. The present method used potassium monochromate (KCrO) to generate the KCrO on demand in the first phase. In addition, miniaturizing the procedure to semi microanalysis decreased the consumption of reagents and samples. In the second phase, mercury sulfate was eliminated as part of the digestion mixture through the introduction of sodium bismuthate (NaBiO) for the removal of chlorides from the sample. The modified method, the potassium monochromate closed-tube colorimetry with sodium bismuthate chloride removal (KMCC-Bi), generates the potassium dichromate on demand and eliminates mercury sulfate. The semi microanalysis procedure leads to a 60% reduction in sample volume and ≈ 33.33 and 60% reduction in monochromate and silver sulfate consumption respectively. The LOD and LOQ were 10.17 and 33.90 mg L for APHA, and 4.95 and 16.95 mg L for KMCC-Bi. Recovery was between 83 to 98% APHA and 92 to 104% KMCC-Bi, while the RSD (%) ranged between 0.8 to 5.0% APHA and 0.00 to 0.62% KMCC-Bi. The method was applied for the UV-Vis spectrometry determination of COD in water and wastewater. Statistics was done by MINITAB 17 or MS Excel 2016. ᅟ Graphical abstract.

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Radon in potable water has become an issue of public health concern, especially when consumed or used directly from source for domestic purposes without any pre-treatment. In this study, 222Rn concentration in 22 water samples collected from 2 groundwater sources (open wells, 12 samples and boreholes, 10 samples) in Bosso town, North central Nigeria were measured using Durridge RAD-7 radon detector with RAD-H2O accessories. 222Rn concentrations in open wells varied from 2.1±0.7 to 27.9±2.5 Bq L-1 with a mean of 10.2±1.5 Bq L-1, while that in boreholes ranged from 2.8±1.1 to 39.2±1.5 Bq L-1 with a mean value of 14.3±1.7 Bq L-1. These values are lower than the 100 Bq L-1 upper limit proposed by the European Union Commission, above which any practical intervention may be necessary. Mean annual committed effective dose to adults, children and infants from ingestion of water were 74.64, 71.58 and 53.17 \muSv y-1 respectively for the open wells and 104.24, 99.96 and 74.26 \muSv y-1 respectively for borehole water samples. Mean whole body dose due to ingestion and inhalation of waterborne radon from open wells and boreholes are 27.56 and 38.48 \muSv y-1 respectively, which are below the reference level of 0.1 mSv y-1 for potable water recommended by the World Health Organization for public safety. The excess lifetime cancer risk were 0.10 × 10-3 for the open wells and 0.13 × 10-3 for the boreholes, which are lower than the world safety limit 0.29 × 10-3. Water from the two groundwater sources investigated is therefore fit for consumption and other domestic usage from the point of view of radiation protection.

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