In this study, Skin-lightening creams commonly sold in Mbarara municipality were analyzed for chemical parameters (pH, thermal stability and fatty substance content), total hydroquinone, Lead, Mercury, and Arsenic contents. Total heavy metal content was determined by atomic absorption spectrophotometry. The levels of hydroquinone were determined using High Performance liquid chromatography (HPLC). All the creams showed detectable mean levels of mercury, ranging from 0.07±0.01ppm to 0.33±0.01ppm. Only 26.31% of the creams showed detectable levels of lead and 15.79% creams recorded detectable levels of arsenic. The mean levels of hydroquinone ranged from 0.54±0.02% to 4.47±0.02%. All the creams passed the thermal stability and fatty substance content tests. However, all the creams had very low pH values below the recommended 4.5- 8.5 pH ranges by Uganda National Bureau of Standards (UNBS). The levels of mercury, arsenic and lead in the samples were less than the UNBS, European Union and US Food and Drug Administration’s acceptable limits. Only 84.2% of the cream samples analyzed contained hydroquinone levels higher than the recommended WHO limit of 2%. The use of such creams may lead to serious health hazards. While the low concentrations of heavy metals detected in the cream samples analyzed do not pose any potential risk to consumers, repeated application of these creams may cause a cumulative effect over prolonged exposure. The low pH values may cause skin irritations.  Therefore, the community needs to be sensitized on the implications of using skin lightening creams and UNBS should conduct periodic analysis to ascertain the levels of hydroquinone, heavy metals, and chemical requirements of skin lightening creams sold in Uganda as well as encourage manufacturers to state the exact bleaching agents in their creams.

Sodium thiosulphate reduced phosphomolybdate (STRP) was prepared based on the condensation of phosphate and molybdate ions in aqueous acid medium to form phosphomolybdic acid (PMA) followed by its reduction to molybdenum blue. The STRP was characterized by ultravioletvisible spectroscopy, fourier transform infrared spectroscopy, scanning electron microscopy, raman spectroscopy and X-ray powder diffraction. Comparison of spectral data of the STRP to that of the unreduced phosphomolybdate, indicates that the Keggin structure is retained even after reduction. X-ray diffraction data and SEM/EDX results suggest formation of crystalline cubic phosphomolybdate crystals.

A simple spectrophotometric method for the determination of low levels of the orthophosphate (PO43-) in environmental water systems is reported. The method is based the formation of the phosphomolybdate from the condensation of molybdate and orthophosphate in aqueous acid medium followed by reduction with sodium thiosulphate to form phosphomolybdenum blue. The system obeys Beer’s law at 880 nm (λmax) in the 0.005–0.06 mg P mL-1 phosphate concentration range. Molar absorptivity, Sandell’s sensitivity and correlation coefficient values for the determination were 57526 L mol-1 cm-1, 0.2835 μg cm-2 and 0.9948 respectively. The limit of detection was 2.213 x 10-3 mg P mL-1. The results of PO43- determination in water samples obtained using the spectrophotometric method developed in this study, compare favourably with those generated using the Murphy and Riley method which is commonly used for this analysis. Therefore, the study ably demonstrates the suitability of the present spectrophotometric method for analysis of the orthophosphate in environmental water samples.

Background Aflatoxicosis associated with the consumption of aflatoxin contaminated maize and maize products has been reported in the central part of Tanzania (Chemba, Kondoa, and Kiteto), however little is known about the prevalence of aflatoxin contamination in cattle’s concentrate feed, yet maize constitutes a major component in the feed. The presence of aflatoxin in cattle’s concentrate feed lead to reduced growth rate, and milk production and results ina carryover effect on human being resulting in human health effect. This study aimed at determining the prevalence of aflatoxins contamination, the level of awareness, knowledge, and practices associated with aflatoxin contamination, and control in cattle concentrate feeds produced and sold in Dar es Salaam, Tanzania. Method Eighty one samples of concentrate feed were collected from concentrate feed processors and sellers in four clusters Ilala, Kinondoni, Temeke, and Ubungo. The samples were nalyzed by Enzyme linked Immuno-sorbent Assay and High-Performance Liquid Chromatography-Fluorescent Detector. The level of contamination was compared to the WHO/EAC/TBS recommended limit. Also eighty one concentrate processors and sellers were interviewed to assess the level of awareness, knowledge, and human practices associated with aflatoxin contamination and control. Results Sixty three 63/81 (78%) samples were contaminated with total aflatoxin (TAFs) ranging from LOD to 161.32 ppb, mean of 25.89 ± 3.3 ppb which was significantly higher than the tolerable WHO/TBS limit of 15ppb total aflatoxins (P = 0.002), Level of AFB1 in concentrate feed was ranged from LOD to 133.17 ppb, mean 18.87 ± 2.45 ppb and was significantly higher than the tolerable WHO/TBS limit 10 ppb for AFB1 (P = 0.001). The level of AFB2 was ranged from LOD to 8.21 ppb, mean 1.82 ± 0.27 ppb, AFG1 (LOD to 75.06 ppb, mean 7.75 ± 2.32 ppb) and AFG2 (LOD to 7.87 ppb, mean, 1.30 ± 0.350 ppb), among aflatoxin the level of contamination was AFB1 > AFG1 > AFB2 > AFG2, however, AFB2 and AFG2 had significant same level of contamination (p = 0.518). The samples collected from Temeke and Ilala were significant highly contaminated with aflatoxin than the WHO/TBS recommended limit (15 ppb), with TAFs of 33.63 ± 3.96 ppb, p-value = 0.00015, 30.78 ±, 7.05 ppb, p-value = 0.034 respectively, while those from Kinondoni and Ubungo were not significantly higher than the recommended standard 15ppb (p-value, 0.71,0 .742) respectively. The level of awareness was 38% and not significant (p = 0.353) and 58/81 (72%) of respondents were not aware of the negative health effect of aflatoxins. The poor storage facility, poor handling practices, temperature, humidity and lack of awareness were the predominant factors identified to contribute a high level of aflatoxin contamination. Conclusions The results indicated that the concentrate feeds had aflatoxin concentrations which may pose risk to animals and/or human beings, economic losses due to increased cost of treatment and reduced cattle production. The use of improved pre and post-harvest management technologies, and awareness creation to animal feed value chain actors are important steps in the reduction of this problem.