Assessing the enrichment of heavy metals in surface soil and plant (Digitaria eriantha) around coal-fired power plants in South Africa

Abstract

Nine metals (Fe, Cu, Mn, Ni, Cd, Pb, Hg, Cr, and Zn) were determined in soil and Digitaria eriantha plants within the vicinity of three coal power plants (Matla, Lethabo, and Rooiwal), using ICP-OES and GFAAS. The total metal concentration in soil ranged from 0.05 ± 0.02 to 1836 ± 70 μg g(-1), 0.08 ± 0.05 to 1744 ± 29 μg g(-1), and 0.07 ± 0.04 to 1735 ± 91 μg g(-1) in Matla, Lethabo, and Rooiwal, respectively. Total metal concentration in the plant (D. eriantha) ranged from 0.005 ± 0.003 to 535 ± 43 μg g(-1) in Matla, 0.002 ± 0.001 to 400 ± 269 μg g(-1) in Lethabo, and 0.002 ± 0.001 to 4277 ± 201 μg g(-1) in Rooiwal. Accumulation factors (A) of less than 1 (i.e., 0.003 to 0.37) at all power plants indicate a low transfer of metal from soil to plant (excluder). Enrichment factor values obtained (2.4-5.0) indicate that the soils are moderately enriched with the exception of Pb that had significant enrichment of 20. Geo-accumulation index (I-geo) values of metals indicate that the soils are moderately polluted (0.005-0.65), except for Pb that showed moderate to strong pollution (1.74-2.53).

Human health risk assessment of heavy metals in soils and commonly consumed food crops from quarry sites located at Isiagwu, Ebonyi State

“…Thus, root tubers accumulated more heavy metals compared to other food crops. This is in consonance with previous studies [23][24][25][26][27][28] and followed the general trend observed for trace metal accumulation in food crops [28]. Among heavy metals analyzed in this study, iron levels was highest in edibles and rhizosphere soils which could be as a results of its presence in the earth crust i.e., parent rock material.…”

“…Mean manganese concentration in food samples from Ishiagu was within the range of 10.16 mg/kg dry weight (dw) to 177.4 mg/kg dw while those from Umudike was within the interval of 0.20 mg/kg dw to 245.90 mg/kg dw. About 58% and 50% of samples from Ishiagu and Umudike respectively were above the joint FAO/WHO permissible limits for Mn in edible plants [23]. Mean manganese concentration in rhizosphere soils increased from 65.55 mg/kg to 248.50 mg/kg dw and 6.50 mg/kg dw to 275.60 mg/kg dw for Ishiagu and Umudike respectively.…”

Anthropogenically disturbed potentially toxic elements in roadside topsoils of a suburban region of Bishkek, Central Asia

“…One argument is derived from the geochemical survey. Soil investigations of geochemical baselines (Salminen & Gregorauskien, ), which are fundamental and valuable for the assessment of PTE contamination (Okedeyi, Dube, Awofolu, & Nindi, ; Wu et al., ; Zahra, Hashmi, Malik, & Ahmed, ), should avoid sampling within 200 m of the highway in this region. The other argument can be made for food cultivation.…”

Heavy Metal Uptake and Transport in Plants

“…In addition to other heavy metals, polonium-210 is found in the vicinity of phosphate fertilizer industry as a major contaminant source (Aoun et al 2010). Mining, smelting, and coal-fired power plants also contribute to the accretion of heavy metals in soils and plants (Okedeyi et al 2013). High altitude points with comparatively less anthropogenic activities are usually less infested with these metals (Cheng et al 2013).…”