Quantification of Heavy Metals in Breast Milk Samples Sampled from Kilimani/Kidoti in Zanzibar

People of Zanzibar are perpetual users of tomatoes.  Different varieties of tomatoes are regularly consumed in day-to-day meals in Zanzibar. These fruits are farmed under different settings varying from purely organic mode to extensive use of agrochemicals. It is well known that the use of agrochemicals may give rise to heavy metals contaminations with significant health impacts to consumers. The use of fertilizers and pesticides in some areas during cultivation may bring about individuals to eat tomatoes together with harmful heavy metals. However, no study has been done to find the quantity of heavy metals entered in consumers’ bodies. The objective of this study was to quantify heavy metals present in breast milk of individual tomato consumers. The methodology used was sampling, processing, digestion and analysis. The instrument used for analysis was Atomic Absorption Spectrometer (AAS). Samples were collected, digested with HNO3 and H2O2 in a semi–closed glass digestion apparatus. After cooling, volume was adjusted to 25 ml with distilled water and analyzed by AAS. Zinc detected by AA spectrometer ranged from 231 μg/l to 1466 μg/l of milk, with average of 900±457 μg/l. Cadmium ranged from 24.1 μg/l to 35.9 μg/l with average of 31.1±3.46 μg/l. Lead ranged from 32.4 to 1630 μg/l with average of 707±582 μg/l. The concentration of Al metal, which was detected in only one sample, was 0.91 μg/l. The results show that breast milk contains heavy metals contaminants necessary to be removed before infant feeding

Quantification of Lycopene from Tomatoes and Watermelons by Using Beer-Lambert Principle

Red tomatoes and red-fleshed watermelons contain a high level of lycopene.  It is well known that lycopene is precursor to vitamin A. In Uganda, and East Africa in general, there are so many tomato and watermelon varieties with little information on their lycopene content. However, no study has been done to estimate the quantity of lycopene in fresh tomatoes and watermelons in Uganda. The objective of this study was to quantify lycopene by using Beer-Lambert Principle. The varieties were bought from Nakulabye market in Kampala, and extracted by using solvent system of acetone/ethanol/ hexane (5ml/5ml/10ml). Stirring on ice was done for 15 minutes. 3 ml of deionized water was added after shaking. Samples were shaken for 5 minutes on ice and then left at room temperature for 5 minutes to allow the separation of phases. The lycopene layer were then separated and scanned in UV-VIS spectrophotometer. The results showed that the lycopene concentration ranged from 27 μg/g to 115 μg/g with % relative error ranged from 2.86 to 3.14, the standard error ranged from ± 0.013to ± 0.015,and standard deviation ranged from 7.38 to 29.5.  Both watermelons and tomato varieties contain the appreciable quantities of lycopene which is the significant nutrient for human body in daily life.

Organochlorine pesticides and polycyclic aromatic hydrocarbons in marine sediments and polychaete worms from the west coast of Unguja island, Tanzania

The coastal areas of Stone Town, on the island of Unguja that is part of Zanzibar, are subjected to different anthropogenic activities and receive untreated municipal wastes that are likely to carry organic pollutants that can bio-accumulate in marine organisms. Sediments and polychaete worms Capitella capitata collected from coastal sites north and south of Stone Town were analysed for organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) using GC-MS to assess their pollution status in the coastal environment and uptake by the food web. The analysis revealed quantifiable concentrations of DDTs, cyclodienes, and HCHs, and six of the 11 USEPA-priority PAHs. The concentration ranges of ΣOCPs were 0.1–100 ng/g dm (dry mass) and 8.5–96 ng/g lm (lipid mass) in sediments and worms, respectively. The concentrations of ΣPAHs6 ranged from non-detectable to 27 ng/g dm in sediments and non-detectable to 18 ng/g lm (lipid mass) in worms. Malindi harbour was the most contaminated of all sites with respect to the pollutants we measured in both sediments and worms. The relative compositions of the OCPs suggest legacy use of DDT and technical HCH, and more recent use of lindane. The relatively higher proportion of low molecular mass PAHs to high molecular mass PAHs suggests major contributions from petrogenic sources in the study area. The results demonstrated bioavailability and uptake of OCPs and PAHs to the food web via C. capitata. Concentrations of DDTs, HCHs, and dieldrin exceed sediment quality guidelines, indicating risk to sediment-dwelling organisms, as well as organisms that eat them. It is likely that other toxic compounds are present, suggesting that the current assessment may underestimate the risk. Due to the indicated risk, further work is needed to look at coastal distributions, terrestrial concentrations, and accumulation of pollutants into higher trophic level organisms of Zanzibar and associated seas.Funding agencies: Building Stronger University (BSU-II) programme of the State University of Zanzibar, Tanzania; Western Indian Ocean Marine Science Association (WIOMSA), Tanzania through a MARG II programme</p

Adsorption-desorption of chlorpyrifos in soils and sediments from the Rufiji Delta, Tanzania

Batch adsorption-desorption equilibrium techniques were used to investigate the adsorption capacity and influence of salinity on partitioning of the insecticide chlorpyrifos between water and soil or water and sediments from the Rufiji Delta. The data were fitted to different adsorption-desorption models and the hysteresis index was calculated using the ratio between the Freundlich exponents for desorption and adsorption, and secondly, the difference in area under the normalized adsorption and desorption isotherms using the maximum adsorbed and solution concentrations. The data showed non-linear adsorption and that chlorpyrifos was strongly adsorbed to soil and sediments from the Rufiji Delta. The linearized adsorption coefficient (KD) and Freundlich adsorption coefficient (Kf) correlated significantly with organic carbon content. Chlorpyrifos adsorption as well as hysteresis calculated by both methods decreased with salinity (i.e. the sediment adsorbs increasing amounts of chlorpyrifos with decreasing salinity). This indicates that settling of freshwater sediments is among the major removal pathways of the chemical from the water column, but increased turbulence during high tides may resuspend settled sediment simultaneously increasing salinity and re-dissolve chlorpyrifos. However, discharge of fresh water, particularly during heavy rains, increases the trapping efficiency of the sediments. The theoretical approach developed showed that the Langmuir model describes the desorption data better than the Freundlich model, and that a better index of hysteresis is one that considers areas under the adsorption and desorption isotherms, provided the desorption isotherm is described by the normalized Langmuir isotherm and the adsorption isotherm by the normalized Freundlich isotherm

Building capacity for the management of coastal resources in Tanzania and Zanzibar

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