Abstract:This study involved the determination of heavy metals of Cd, Cr, Cu, Pb and Zn in cauliflower (Brassica oleracea L.var botrytis L.), carrot root (Daucus carota L.), tomato fruit (Lycopersicum esculentum Mill.), onion bulb (Allium cepa L.) and leafy cabbage (Brassica oleracea L. var capitata L.) and the respective soils from Lushoto District, Tanzania. Samples were collected from eight growing sites. The accumulated heavy metals were quantified and the levels compared to the FAO/WHO CODEX-STAN 179:2003 and TZS 972:2007 contamination limits for such produce. The methodology involved random sampling, extraction of the metals from the vegetable and soil and determination of heavy metals by using ICP-OES and GFAAS. The levels of Cu in all vegetables were below the FAO/WHO limit while levels of Cr and Zn in all vegetables were found to be above this limit therefore advocating a health risk for consumers. Pb was only found in carrots at 2 sites (Montisory and Resource centre) and in onions at the market all at levels above the FAO/WHO limit while Cd was only found in onions and tomatoes at 2 sites (market and Montisory) at above the FAO/WHO limits. Vegetables especially onions from the Mlalo market advocate a health risk to consumers. Levels of heavy metals in the soils were below the limits of the Tanzanian standard (TZS 972: 2007) and were lower than levels found in vegetables. However, the bioconcentration factor for Cr, Pb, Cd and Zn in all vegetables and tomatoes where they were detected except for cabbages at the Garage site were found to be above 1, an indication of high uptake of heavy metals in the vegetables from the soil. Cu at 80% of the sites had a BCF lower than 1 indicating that Cu was more abundant in the soil compared to the vegetables. These results suggest that these vegetables from Lushoto district are not safe for consumption in their raw state.

Abstract:The physicochemical composition of pomegranate (Punica granatum L.) fruits from Kimara, Dar es Salaam during open air storage ripening process were determined. The ash, titratable acidity, crude fat, crude fiber, moisture and sugars content were determined by proximate analysis. Ascorbic acid contents were determined using the 2,6-dichlorophenol-indophenol dye method while mineral elements and heavy metals were determined by Flame Atomic Absorption Spectrophotometry (FAAS). The fruits were always harvested at the mature stage and allowed to ripen during open air storage. The determinations were done immediately after arrival at the laboratory and thereafter at intervals of two days from the day of harvest to the 8 th day. The results showed that fresh pomegranate fruits had high moisture content range of (89.6%-77.5%), low titratable acidity (<0.86% ca), low crude fat (0.30 g/100 g-fw), low ash content (0.35 g/100 g-fw), moderate crude fibre content (4.20 g/100 g-fw), high ascorbic acid content (53.7 -20.4 mg/100 g-fw), high total sugars content (48.9% -29.1%), moderate reducing sugar content (42.0% -25.5%) and sucrose content (5.7% -2.0%). Of the mineral elements (K, Ca and Na) determined, the highest content was of Ca (1086 mg/100 g-fw.). Heavy metals (Fe, Zn, Cu, Pb and Cd) content was very low in the pomegranate fruits, ranging between <0.0015 mg/100 g-fw for Cd and 0.84 mg/100 g-fw for Fe. Except for sucrose which was increasing during storage ripening, the moisture content, acidity content, ascorbic acid content, total sugar content and reducing sugar content were all decreasing as the fruit was ripening while in storage. There were no significant changes during storage ripening for levels of crude fat, ash, minerals and heavy metals. The results of this study suggest that these fruits could highly contribute in the improvement of the nutrition of consumers.

Abstract:The concentrations of heavy metals of Cd, Cu, Cr, Pb and Zn were determined in cauliflower (Brassica oleracea L.var. butrytis L.), carrot root (Daucus carota L.), tomato fruit (Lycopersicon esculenta Mill.), onion bulb (Allium cepa L.) and leafy cabbage (Brassica oleracea var. capital capitata L.), and the respective soils from Morogoro region, Tanzania. The accumulated heavy metals were quantified and levels compared to FAO/WHO (2003) and TZS (2007) safety limits for such produce. The methodology involved random sampling, extraction of the metals from the tomatoes, vegetables and soil and determination of heavy metals by using ICP-OEC and GFAAS. The results showed that levels of Cd, Cu, Cr, Pb and Zn at 90% of the sites in vegetables and tomatoes were above the FAO/WHO limit. The mean concentrations of Cd, Cr, Pb and Zn in all vegetables and tomatoes except Cu were also found to be above this limit therefore advocating a health risk for consumers. Levels of heavy metals in the soils were below the limits of the Tanzanian standard (TZS 972: 2007) and were lower than levels found in vegetables. The bioconcentration factor for Cu recorded 1 for tomatoes and cabbage at Towelo and below 1 for tomatoes and cauliflowers from Mgeta. Cd in onions at Mgeta as well recorded below 1. However, the bioconcentration factor for these heavy metals in vegetables and tomatoes in all other sites were found to be above 1 in all heavy metals an indication of high uptake of heavy metals in the vegetables and tomatoes from the soil. These results suggest that such vegetables and tomatoes might place the consumers at health risk; therefore they are not safe for consumption in their raw state.