Assessment of Heavy Metal Pollution of Agricultural Soil, Irrigation Water, and Vegetables in and Nearby the Cupriferous City of Lubumbashi, (Democratic Republic of the Congo)

Abstract

Lubumbashi (DR Congo)—the capital of copper mining—has been considered as one of the richest mining regions of the world for more than a decade. These riches have brought along multiple mining companies responsible for soil, river water and vegetable pollution, as in many African cities. The aim of the present study was to quantify and evaluate the pollution levels and the potential sources of soil, irrigation water and vegetable contamination by the metals As, Cd, Cr, Cu, Pb, Co and Zn in the urban gardens of Lubumbashi (DR Congo). The contamination, pollution and enrichment levels of the gardens were determined based on different indices in order to rank the soils. The results show that soils, waters and vegetables present contamination levels that represent a serious concern for human health. All soils presented contamination indices ranging from low (72% of the soils) to very high (3.4% of the soils) metal (copper, lead, zinc) contamination. The Cu and Cd contents varied between 1355 mg/kg et 236 mg/kg, much higher than the World Health Organisation (WHO) thresholds (100 mg/kg for Cu and 2 mg/kg for Cd). Moreover, the water used for crop and garden irrigation presented high Pb (57% of the waters), Fe (52%), Cu (19%) and Cd (10%) contamination levels, above the Association Française de Normalisation (AFNOR) U4441 toxicity thresholds (2 mg/kg for Cu; 0.1 mg/kg for Fe and 0.01 mg/kg for Pb) for crop irrigation. Finally, the vegetables produced in these gardens and sold in the local markets had very high metal content (47% contained Cu; 100% contained copper and cobalt) above the WHO standard (10 mg/kg for Cu, 2 mg/kg for Cd and 1 mg/kg for Co) for human consumption. In the face of these issues, it would be preferable to consider cheaper, more sustainable techniques that reduce soil-to-plant metal transfer.

Accumulation of phytotoxic metals and metalloids in vegetable continuum subjected to different irrigation streams: a threat towards nutritional security

“…Moreover, anthropogenic activities are the primary cause of the pollution of soil and groundwater (Hassan et al, 2021). The production of food crops on these contaminated soils with contaminated irrigation water resulted to the bioaccumulation of potentially toxic substances in plants, which increased significant health risks for people (Riaz et al, 2021;Mununga Katebe et al, 2023). Findings of the current study revealed similar results in which polluted irrigation sources resulted in higher bioaccumulation metals and metalloids in the ridge gourd fruit (Tables 1-3).…”

“…The solubility of heavy metals increases with a decrease in pH, leading to higher plant accumulation and absorption. This can pose possible health risks and the health of consumers (Mununga Katebe et al, 2023;Tariq et al, 2023).…”

Accumulation of Trace Metals in Fruits from Mango and Syzygium guineense Growing in Residential Households from a Contaminated District of Lubumbashi (DR Congo): Is Fruit Consumption at Risk?

“…Consistent with the concentration values in soils and plants, the results showed a higher proportion of values above the FAO and WHO limits in Penga Penga ( Figure 2 ). In this case, the consumption of mango and S. guineense fruits and leaves may constitute an additional factor for exposure to trace metals, as already reported for other plant products in the region [ 7 , 44 , 45 ]. Nevertheless, calculations of the SWC showed that the consumption of S. guineense fruit is limited to 6.6 kg by the Cd concentration, while it is limited to 9 kg per week for mango flesh (and skin) by the Pb concentration ( Table 5 ).…”

Static and Dynamic Source Identification of Trace Elements in River and Soil Environments Under Anthropogenic Activities in the Haraz Plain, Northern Iran

“…Natural sources of trace elements are geological formations, weathering of rocks, soil erosion and volcanic activities (Arfaeinia et al, 2019). Anthropogenic sources include mining (Qiao et al, 2023), industrial processes (Long et al, 2021), agricultural practices (Mununga Katebe et al, 2023), wastewater discharge (Xia et al, 2023), surface runoff (Gao et al, 2022), transportation (Faisal et al, 2022), dam construction (Çevik et al, 2009) and many others.…”