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. 2024 Jan 18;196(2):170.
doi: 10.1007/s10661-023-12283-6.

Concentrations and health risks of selected elements in leafy vegetables: a comparison between roadside open-air markets and large stores in Johannesburg, South Africa

Sutapa Adhikari  1 , Madeleen Struwig  2
Affiliations

Concentrations and health risks of selected elements in leafy vegetables: a comparison between roadside open-air markets and large stores in Johannesburg, South Africa

Sutapa Adhikari et al. Environ Monit Assess. .

Abstract

This study compared concentrations and health risks of selected elements (Al, As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Zn) in leafy vegetables (coriander, lettuce, mint, spring onion, swiss chard) from roadside open-air markets (OM) and large stores (supermarkets: SM, vegetable markets: VM) in Johannesburg, South Africa. Along with washed leaves (OMW, SMW, VMW), unwashed OM leaves (OMUW) were assessed to investigate the contribution of deposition. The findings revealed that OMUW leaves had the highest concentrations of all elements. Furthermore, compared with washed leaves, OMUW leaves showed significantly higher (p < 0.05) mean concentrations of Cd, Hg, Ni and Pb, elements that typify the composition of polluted urban air. Bi- and multivariate analysis indicated anthropogenic origin of most elements in OM leaves and several in SMW and VMW leaves. Although only OMUW leaves exhibited hazard quotient above the safe threshold of 1 for Cd, Cr, As and Ni, hazard index exceeded this safe limit in all samples (OMUW (11.77) > OMW (1.83) > SMW (1.29) > VMW (1.01)). Determined cancer risk for Cd and As was greater than 1 × 10-6 in both washed and unwashed leaves, and the greatest cancer risk was estimated for OM leaves. Thorough washing of OM vegetables with water reduced non-carcinogenic risk (84%) and cancer risk (74‒87%) markedly. In conclusion, residents primarily relying on open-air markets for their regular leafy vegetable supplies might face far more severe lifelong health implications compared to customers of large stores in Johannesburg.

Keywords: Arsenic; Cadmium; Contamination; Deposition; Nickel; Pollution.

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Conflict of interest statement

The authors have no relevant financial or non-financial interests to disclose.

Figures

Fig. 1
Fig. 1
Elements for which mean concentrations exceeded permissible levels (dashed lines) in leafy vegetables, a aluminium, b cadmium, c chromium, d zinc, e arsenic, f mercury and g nickel. OM open-air markets, SM supermarkets, VM vegetable markets, UW unwashed leaves, W washed leaves
Fig. 2
Fig. 2
Health risks of selected elements in leafy vegetables from OM, SM and VM, a percentage contribution of hazard quotient (HQ) of each element to hazard index (HI), b cancer risk of As, Cd and Pb, c estimated weekly intake of aluminium and d estimated weekly intake of mercury. Cancer risk: dotted line, 1 × 10‒6; solid line, 1 × 10‒4. OM open-air markets, SM supermarkets, VM vegetable markets, UW unwashed leafy vegetables, W washed leafy vegetables
See this image and copyright information in PMC

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