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Zinc as its citrate or sulphate salt is added to some toothpaste as a bactericide to reduce the presence of bacteria in the mouth. These bacteria can form plaque or produce acids which cause dental decay and halitosis. Zinc salt is added at amounts which are enough to show activity against oral bacteria without causing toxicity to the user. Five commercial samples of different brands of toothpaste (TP-A, TP-B, TP-C, TP-D and TP-E) were purchased from different pharmacy stores in Ogige and Eko markets, Nigeria and analysed for the presence of zinc using atomic absorption spectrophotometric method. The samples were digested with deionized water and HNO3, centrifuged and filtered. The absorbance of the supernatants obtained was read with a spectrophotometer. Calibration curves for zinc sulphate and zinc citrate were obtained with regression (R²) values of 0.9992 and 0.9973, respectively. The equation obtained from the curves used in determining the content of zinc in the samples. The zinc content (% w/w) of samples was determined to be 0.8467%, 0.8127%, 0.0119%, 0.0188% and 0.0305%, respectively. These values were well below the maximum permissible level of zinc in toothpaste samples but were within the upper limit for daily zinc intake. [ABSTRACT FROM AUTHOR]

In recent times, there had been reported cases of Pb poisoning in Anka gold mining area, Northwest Nigeria. Therefore, this study was carried out to determine the extent of bioaccumulation of heavy metals in the hairs and nails of children in the area. Forty samples (twenty nails and twenty hairs) samples were collected from ten boys and ten girls of ages 5–9 residing in the area. To ascertain the sources of heavy metals in children, 15 soils samples, 15 groundwater samples, 5 samples of mine tailings, and 5 plants samples were collected. Hair and nails of the subjects were collected using internationally acceptable techniques. All samples were kept in uncontaminated ziplock bags prior to laboratory preparation and analysis. The samples were cleaned using nonionic detergent (triton X-100) and deionized water. The hairs and nails were digested with 10 mL of 6:1 mixture of nitric acid and perchloric acid. The soils, mine tailings, and plants were air-dried at room temperature, sieved, and chemically digested using the aqua regia method. The concentrations of metals in all the samples were determined using high-performance liquid chromatography–inductively coupled plasma–mass spectrometry. Statistical analysis was employed to unravel potential sources of metals in the media. Results showed that heavy metals in children of the area are above results from similar studies and pathological ranges for heavy metals in hairs and nails. Also, heavy metals in environmental media are above the recommended standards. Multivariate analysis showed that the metals are mainly from mining and other anthropogenic sources. Results of correlation between heavy metals in hairs and nails with those in geological samples revealed that heavy metal that bioaccumulates in the children of this area are mostly from contaminated environmental media. It is recommended that complete remediation and effective health education be carried out in the area. [ABSTRACT FROM AUTHOR]

Abstract: Kaolinite clay obtained from Ubulu-Ukwu, Delta State in Nigeria was modified with polyvinyl-alcohol (PVA) reagent to obtained PVA-modified Kaolinite clay. Kinetic and equilibrium data were obtained for the batch adsorption of Pb2+ onto PVA-modified Kaolinite clay. Time-dependent Langmuir and pseudo-second order kinetic models (TDLM and PSOM) were developed to predict the optimized minimum operating time for the adsorption of Pb2+ onto PVA-modified Kaolinite clay in a two-stage batch adsorber system. Results obtained suggest that the two-stage batch adsorber process leads to improved contact time and increased percentage Pb2+ removal. Data from both models (TDLM and PSOM) were compared using t-test and F-test and were found to be precise enough for use in the optimization of kinetic data for a two-stage adsorption of Pb2+ ions from aqueous solution. [Copyright &y& Elsevier]