Copper and lead levels in two popular leafy vegetables grown around Morogoro Municipality, Tanzania

Abstract

Abstract:A study was carried out to determine the levels of two heavy metals, Lead (Pb) and Copper (Cu), in two popular leafy vegetables grown around Morogoro Municipality in Tanzania. Vegetable samples of Pumpkin leaves (Cucurbita moschata) and Chinese cabbage (Brassica chinensis) were collected from three sites and analysed for their concentrations of the two metals using an Atomic Absorption Spectrophotometer. The three sites, namely Mazimbu, Kihonda and Towelo are located within a 10 km perimeter. The site selection was based on the anticipated levels of contamination of the water used for irrigation. The results showed that the levels (mg/100g dry weight) ranged from 0.885 to1.39 for Copper and 0.05 to 0.315 for Lead. The levels of Lead and Copper varied between the vegetable varieties and from site to site. Vegetables from Mazimbu showed higher concentration levels of the two metals compared to the other sites in both varieties. Towelo vegetables had relatively low concentrations. There was a significant difference (P<0.05) in levels of the two metals across the sites but there was no significant difference (P>0.05) in the levels of Copper between the two vegetable varieties from all the three sites. There was a significant difference (P<0.05) in the levels of Lead between the vegetable varieties. The levels of both Lead and Copper in the two vegetables were found to be below the maximum permissible levels recommended by FAO/WHO for the two metals in vegetables.

Heavy Metal Levels in Soil, Tomatoes and Selected Vegetables from Morogoro Region, Tanzania

“…In our study, in soil where pH was recorded near neutral (7.22), low concentrations of heavy metals were recorded in the soil contrary to [19]. This might be due to vegetables and tomatoes absorbing heavy metals through leaves exposed to air from polluted environment [16].…”

“…A similar study was conducted in Morogoro for pumpkin and chinese cabbage by Chove et al [16]. Lugwisha and Othman [17] …”

“…Samples were stored in sealed pre-cleaned polyethylene bags and transported to the Chemistry Department for investigation. [16] method which was followed with minor modifications was used for vegetable and tomato samples collection. The collected samples were first washed with tap water and rinsed three times with distilled water to remove surface pollutants and any items adhering to the surfaces.…”

“…The results of Cu (7.19 µg/g-dw) in onion at Kihonda could have been contributed by industrial effluents and indiscriminate disposal of domestic or sewages directed to the stream of Ngerengere, which are untreated or partially treated [16]. At Towelo, where there are no industrial activities apart from horticultural activities, the concentration of Cu could have been contributed by the nature of rocks, fertilizer, atmospheric deposition and other sources [22] The concentrations of Cu in soils from the respective locations ranged between 0.08 µg/g-dw at Mgeta and 1.5 µg/g-dw at Towelo.…”

Potential human health risk assessment of heavy metals intake via consumption of some leafy vegetables obtained from four market in Lagos Metropolis, Nigeria

“…Chromium depending on the valent state can be beneficial or harmful; the hexavalent state of chromium is harmful (Leopora, 2005). Chromium is known to help maintain normal blood glucose levels by enhancing the effects of insulin (Chove et al, 2006). The most widespread human effect is chromium allergy caused by exposure to chromium (especially Cr (VI) compounds), and they are assumed to cause cancer (RTI, 2000).…”