Potential health risks associated with trace metal pollution have necessitated the importance of monitoring their levels in the environment. The present study investigated the concentrations and compositions of trace metals in dust samples collected from classrooms and playing ground from the selected high schools In Pretoria. Schools were selected from Pretoria based on factors such as proximity to high traffic ways, industrial areas, and residential areas. Thirty-two dust samples were collected from inside and outside the classrooms, where learners often stay during recess period. The dust samples were analysed for trace metal concentrations using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The composition of the elements showed that the concentrations of Zn were more than all other elements except from one of the schools. There were significant differences in the concentrations of trace metals from the schools ( < 0.05). Regular cleaning, proximity to busy road, and well maintained gardens seem to have positive effects on the concentrations of trace metals recorded from the classrooms dust. The result further revealed a positive correlation for elements such as Pb, Cu, Zn, Mn, and Sb, indicating that the dust might have a common source.

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Purpose The study assessed trace metal levels in the leaves, stalks and roots of Spinacia oleracea harvested from soil treated with urine in comparison to chemical fertilizers and biosolids. Methods Spinacia oleracea seedlings were planted on soils pretreated with urine, chemical fertilizers and biosolids. Results The soil treated with chemical fertilizers resulted in an increase of Cr, Pb, Cd, Cu, Ni and Sb while there was an increase in the concentrations of Zn and Hg in the soil treated with urine. The soil with no amendments recorded higher mean values of As and Mn, whereas the biosolids treatment did not show any increases of the trace metals in the soil. The concentration of Mn, Pb and Ni in the leaves and stalks of S. oleracea harvested from soil treated with urine were below the recommended limits for trace metals in edible plants as set by WHO even though the urine treatment recorded the highest concentration of Cd in the roots, stalks and leaves. The S. oleracea harvested from the soil treated with chemical fertilizers showed an accumulation Cu and Mn in the stalks and leaves while those harvested from soil treated with biosolids showed an accumulation of Cr, As, Zn and Ni in the stalks and Cr, Pb and Sb in the leaves and all trace metals in the roots except Cd and As. S. oleracea harvested from the soil with no amendments showed an accumulation of Cr, As, Zn and Ni in the stalks and Cr, Pb, Zn and Sb in the leaves. The transfer factor showed that Cd, Zn, Mn and Sn were translocated from the soil to the leaves even though the concentrations were below acceptable limits for human consumption. Conclusions The study demonstrated that the use of urine as a soil amendment may not facilitate or increase the bioavailability of trace metals in the plant tissues.

The use of African traditional medicine in rural and peri-urban areas is common due to its affordability and accessibility. The study aimed to determine the levels of toxic heavy metals in the medicinal plant (Asclepias fruticosa) samples collected around three mining areas in Brits using ICP-OES. The phytochemical screening analysis was done to indicate the absence or presence of different phytochemicals in the medicinal plant. The results of the qualitative phytochemical analysis indicated the presence of flavonoids, alkaloids, proteins, and carbohydrates in Asclepias fruticosa collected from all the mining areas. The results of the heavy metals showed that the mean highest concentration for all the heavy metals was recorded for Mn from the leaves of the medicinal plants. The trend in the heavy metals accumulation was roots > leaves > stems from all the sites, and the differences were significant (p < 0.05). The range of heavy metals in the plant was in the range Mn (12.33 ± 2.31-85.33 ± 51.07 μg.g-1), Zn (10.67 ± 0.58-60.33 ± 0.56 μg.g-1), Cr (3.43 ± 0.06 -34.90 ± 0.10 μg.g-1), Cu (8.67 ± 0.12-18.8 ± 1.57 μg.g-1), Ni (5.67 ± 0.12-23.23 ± 1.7 μg.g-1) and Pb (0.53 ± 0.013-1.59 ± 0.15 μg.g-1). The values of the heavy metals Cr, Zn, and Ni in the plant exceeded the recommended limits set by WHO for human consumption. Heavy metals in the medicinal plant were accumulated in the roots and not translocated to the stems and leaves. It is therefore recommended that communities staying around the mines should be discouraged from picking and using medicinal plants growing around the mines and should be educated on the safety of medicinal plants growing around the mines.

The use of medicinal plants for the treatment of diseases, including cancer, is acknowledged and accepted in many African nations. Heavy metal contamination of plant materials poses a potential health risk, particularly for populations that are already vulnerable. This study determine the levels of heavy metals in medicinal plant samples used for treatment of skin cancer and evaluate the health risk caused by heavy metals to the adult population in Pretoria, South Africa using inductively coupled plasma mass spectrometry (ICP-MS). The concentrations of metals were as follows; As (< 0.2–1.04 ± 0.026), Cd (0.02 ± 0.00026–0.167 ± 0.006), Pb (0.38 ± 0.01–2.27 ± 0.05), Cr (5.31 ± 0.21– 26.9 ± 3.96) mg/kg and Hg which were lesser than 0.02 mg/kg. The mean concentrations of all analyzed heavy metals are above permissible limit except for Hg which are lower than the permissible limit. The Hazard Quotient (THQ) was less than 1 for all the heavy metals, suggesting that there is no obvious non-carcinogenic health risks associated with the consumption of these medicinal plants for now even though the prolonged use may result in health risks. The ingestion route was identified as the primary contributor to the overall risk by the health index (HI) values in the present study were more than 1, indicating that the combined effects of the heavy metal contaminants present in a particular herbal preparation pose health risk in the long term. Our findings support the need for close monitoring of potential heavy metals concentrations in medicinal plants given to patients from herbal shops.