The distribution of metals in the forest floor of aged conifer stands at a plantation in Northern England

The distribution of the elements Cd, Cr, Cu, Mn, Ni, Pb, Sr, V and Zn has been examined in the horizons of soils under aged Sitka spruce (Picea sitchensis (Bong.) Carr.) stands at a plantation in Northern England. The stands are under first-generation cultivation and are up to 33 years old. Cadmium, Mn, Pb and Zn concentrations were consistently higher in the organic layers than in the underlying mineral soil. This contrasted with the situation for Sr and V. Cadmium, Pb and Zn all showed an increase in concentration in the L + F horizons with stand age and a corresponding increase in the difference between L + F horizon concentrations. Soil pH declined with increasing stand age. Cadmium, Cr, Pb and Zn were all present at higher concentrations in the F horizon than in any other, while Cu and Ni were relatively constant through all the horizons studied. For all nine elements, the H horizon was the largest store of the three organic layers. Calculated rates of accumulation of Cd, Pb and Zn in the L + F horizons gave good agreement with estimated regional atmospheric deposition rates. In comparison to atmospheric deposition, biological mobilisation and deposition of Cd, Pb and Zn make a relatively minor contribution to the surface soil metal burden. Cadmium appeared to be the most readily leached of these three metals from the forest floor, although some transfer of atmospherically-derived Pb to the H+ soil horizons was indicated.     

The distribution and intracellular compartmentation of metals in the endogeic earthworm Aporrectodea caliginosa sampled from an unpolluted and a metal-contaminated site

The tissue distribution of Cd, Cu, Pb, Zn and Ca in the endogeic earthworm Aporrectodea caliginosa living in a non-polluted and a heavy metal polluted soil was investigated. The tissues of animals from the contaminated soil contained greater concentrations of Cd, Pb and Zn than the corresponding tissues of animals from the unpolluted soil. The greatest concentrations of Cd, Pb, Zn, and Ca were primarily accumulated within the posterior alimentary canal (PAC), a tissue fraction which contained the greatest proportion of the whole-worm burdens of the respective metals. Cu was distributed fairly evenly in the tissue fractions investigated. The pattern of accumulation for the 'heavy' metals is broadly similar to that for epigeic earthworms; in contrast, a different pattern of tissue accumulation was found for Ca. In animals from the uncontaminated site, the major elemental constituents of the chloragosomes were P, Ca, Zn and S. A significant positive correlation exists between P and Ca within the chloragosomal matrix. These intracellular vesicles are major foci for Pb and Zn accumulation within the PAC, with 'excess' metals associated with P ligands within the chloragosome matrix. The incorporation of Pb and Zn appears to involve the cationic displacement of Ca. Such compartmentation appears to prevent dissemination of large concentrations of these metals into other earthworm tissues, and may thus represent a detoxification strategy based on accumulative immobilization. No intracellular localization of Cd was identified in the study, although the Cd concentration in the metalliferous soils examined was not exceptionally high. The observations are discussed in the context of a contribution to enhanced understanding of metal ecotoxicology in earthworms by providing baseline data on a little investigated ecophysiological group of earthworms. Comparisons of metal distribution and mechanisms of metal sequestration are made with other ecophysiological groups of earthworms, and the significance of the findings to biomonitoring and toxicity-testing programmes is considered.     

Metal accumulation in poplar plant grown with industrial wastes

In this study the effects of different levels of industrial wastes on growth traits and metal accumulation in aerial portions were determined for Populusxeuramericana clone I-214. The experiment started in April 2003. Scions of Populusxeuramericana clone I-214, were grown outdoor near Pisa (Italy), in lisimeters filled with soil naturally present in the land around the experimental site, were daily drip irrigated, hand weeded, monthly fertilized, pruned for a unique shoot and cultivated with four increasing treatments: soil non-amended, soil amended with 4.8 kgm(-2), with 9.6 kgm(-2) and with 19.2 kgm(-2) of fresh tannery waste. The climatic parameters were daily recorded throughout the whole experiment. Growth relieves were performed during the growing season. After six months since the plantation of the scions, aerial portions of every plant were harvested for biomass and metal content analyses. Data demonstrated that the waste exerted beneficial effects on poplars mainly through a general increase of growth traits and that the nutrients relocation is the mechanisms involved in modulating growth rate. The concentration and the amount of the mineral elements analysed (N, P, K, Na, Ca, Mg, S, B, Fe, Mn, Cu, Zn, Cr) changed determinately among treatments, organs and position. We concluded that phytoremediation strategies of tannery wastes might be possible and sustainable for polar plantations in soil amended with non-hazardous levels of industrial waste, which maintain total heavy metals concentration close to background values.     

Phosphate-induced metal immobilization in a contaminated site

To assess the efficiency of P-induced metal immobilization in soils, a pilot-scale field experiment was conducted at a metal contaminated site located in central Florida. Phosphate was applied at a P/Pb molar ratio of 4.0 with three treatments: 100% of P from H3PO4, 50% of P from H3PO4+ 50% of P from Ca(H2PO4)2, and 50% of P from H3PO4+5% phosphate rock in the soil. Approximately 1 year after P application, soil and plant samples were collected to determine mobility and bioavailability of selected metals (Pb, Zn, and Cu) using sequential extraction procedure and mineralogical characterization using X-ray diffraction (XRD) and scanning electron microscope-energy dispersive X-ray (SEM-EDX) analysis. Phosphorus distribution and soil pH effects were also evaluated. Phosphate was more effective in transforming soil Pb (to 53%) from the non-residual to the residual phase than soil Zn (to 15%) and soil Cu (to 13%). This was because Pb was immobilized by P via formation of an insoluble pyromorphite-like mineral in the surface and subsurface of the soil, whereas no phosphate mineral Zn or Cu was identified. While P amendment enhanced metal uptake in the roots of St. Augustine grass (Stenotaphrum secundatum), it significantly reduced metal translocation from root to shoot, especially Pb via formation of a pyromorphite-like mineral on the membrane surface of the root. A mixture of H3PO4 and phosphate rock was effective in metal immobilization, with less soil pH reduction and less soluble P. Although H3PO4 was effective in immobilizing Pb, its use should be limited to minimize soil pH reduction and potential eutrophication risk.     

Use of the lichen Rhizoplaca melanophthalma as a biomonitor in relation to phosphate refineries near Pocatello, Idaho

Phosphate refineries are point sources for atmospheric Cr, Cd, Zn and P. Concentrations of these and other elements were determined in the lichen Rhizoplaca melanophthalma (Ram.) Leuck. and Poelt in relation to distance and direction from phosphate refineries northwest of Pocatello, Idaho. Elemental concentrations in lichens collected were measured using a multi-element Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). Linear regression analysis revealed that concentrations of Cd, Cr, Zn, and P were negatively correlated with distance from the refineries. The concentrations of the elements Cd, Zn, Ca, Mn, B, and Pb were significantly different among four transects in different directions from the pollution source. Analysis of covariance indicated significant differences in concentrations of Cd, Cr, Zn, P, Cu, Ca, Mg, and K in lichens as a function of distance and direction from the pollution source. These results indicate that this lichen species may be used to determine deposition patterns of air pollutants in semi-arid environments.     

Distribution of elements in needles of Pinus massoniana (Lamb.) was uneven and affected by needle age

Macronutrients (P, S, K, Na, Mg, Ca), heavy metals (Fe, Zn, Mn, Cu, Pb, Cr, Ni, Cd) and Al concentrations as well as values of Ca/Al in the tip, middle, base sections and sheaths of current year and previous year needles of Pinus massoniana from Xiqiao Mountain were analyzed and the distribution patterns of those elements were compared. The results indicated that many elements were unevenly distributed among the different components of needles. Possible deficiency of P, K, Ca, Mn and Al toxicity occurred in needles under air pollution. Heavy metals may threaten the health of Masson pine. Needle sheaths were good places to look for particulate pollutants, in this case including Fe, Cu, Zn, Pb, Cr, Cd and Al.     

Strategies of heavy metal uptake by three plant species growing near a metal smelter

Some higher plant species have developed heavy metal tolerance strategies which enable them to survive and reproduce in highly metal-contaminated soils. We have investigated such heavy metal uptake and accumulation strategies of two absolute metallophyte species (Armeria maritima ssp. halleri and Cardaminopsis halleri) and one pseudometallophyte (Agrostis tenuis) growing near a former metal smelter. Samples of plant parts and soil were analysed for Zn, Cd, Pb, and Cu. In soil, there were two dominant types of metal concentration gradients with depth. Under the absolute metallophytes, extremely high metal contents were measured in the surficial Ah horizon, followed by a strong decrease in the underlying soil horizons (L(11) and L(12)). Under the pseudometallophyte, metal concentrations in the Ah horizon were much lower and fewer differences were observed in metal concentrations among the Ah, L(11), and L(12) horizons. The concentrations of Zn, Cd, Pb, and Cu in Agrostis tenuis roots were greater than concentrations in leaves, indicating significant metal immobilisation by the roots. For C. halleri, Zn and Cd concentrations in leaves were >20,000 and >100 mg kg(-1), respectively, indicating hyperaccumulation of these elements. Armeria maritima ssp. halleri exhibited root concentrations of Pb and Cu that were 20 and 88 times greater, respectively, than those in green leaves, suggesting an exclusion strategy by metal immobilisation in roots. However, Zn, Cd, Pb, and Cu concentrations in brown leaves of Armeria maritima ssp. halleri were 3-8 times greater than in green leaves, suggesting a second strategy, i.e. detoxification mechanism by leaf fall.     

Distribution of elements in needles of Pinus massoniana (Lamb.) was uneven and affected by needle age

Macronutrients (P, S, K, Na, Mg, Ca), heavy metals (Fe, Zn, Mn, Cu, Pb, Cr, Ni, Cd,) and Al concentrations as well as values of Ca/Al in the tip, middle and base sections, and sheaths of current year and previous year needles of Pinus massoniana from Xiqiao Mountain were analyzed and the distribution patterns of those elements were compared. The results indicated that many elements were unevenly distributed among the different components of needles. Possible deficiency of P, K, Ca, Mn and Al toxicity occurred in needles under air pollution. Heavy metals may threaten the health of Masson pine. Needle sheaths were good places to look for particulate pollutants, in this case including Fe, Cu, Zn, Pb, Cr, Cd and Al.     

Impact of soil quality on elemental uptake by, and distribution in, Colocasia esculenta (Amadumbe), an edible root

In this study the elemental distribution of selected essential (Ca, Mg, Al, Mn, Cu, Fe, Co, Cr, Zn, Ni and Se) and the non-essential (Pb, Hg and As) elements were determined in the bulb and peel of Amadumbe (Colocasia esculenta) samples from eight different sites in KwaZulu-Natal, South Africa. The concentration of Se and As in the soil and in the Amadumbe bulbs were below the detection limit of 0.09 μg g?1. The total and bioavailable concentrations of the elements in conjunction with pH, soil organic matter (SOM) and cation exchange capacity (CEC) were determined in the soil samples from the eight sites. Statistical analysis was done to evaluate the impact of soil quality parameters on the chemical composition of the Amadumbe root. The results show accumulation or exclusion of certain elements by the bulb as evidenced by the noticeable increase or decrease of the concentrations of elements, respectively. Ca and Mg were found to be major elements in the range (2000-12000 μg g?1), whilst Mn, Zn, Fe and Al were found to be minor elements in the range (20-400 μg g?1). A general trend observed was that the plant favours the absorption of Zn over Cu. A positive correlation between Mg & Ca, Cu & Fe and Co & Ni was also observed. Statistical analysis revealed that the plant tended to accumulate Mg, Ca, Co, Cr and Pb whilst it excluded Hg and Fe, to a lesser extent.     

Bioavailability and plant accumulation of heavy metals and phosphorus in agricultural soils amended by long-term application of sewage sludge

Amendment of agricultural soils with municipal sewage sludges provides a valuable source of plant nutrients and organic matter. Nevertheless, addition of heavy metals and risks of eutrophication continue to be of concern. Metal behaviour in soils and plant uptake are dependent on the nature of the metal, sludge/soil physico-chemical properties and plant species. A pot experiment was carried out to evaluate plant production and heavy metal uptake, soil heavy metal pools and bioavailability, and soil P pools and possible leaching losses, in agricultural soils amended with sewage sludge for at least 10 years (F20) compared to non-amended soils (control). Sewage sludge application increased soil pH, N, Olsen-extractable-P, DOC and exchangeable Ca, Mg and K concentrations. Total and EDTA-extractable soil concentrations of Cu and Zn were also significantly greater in F20, and soil metal (Cu, Mn and Zn) and P fractionation altered. Compared to the control, in F20 relative amounts of acid-extractable (Mn, Zn), reducible (Mn, Zn) and oxidisable (Cu, Zn) metal fractions were greater, and a dominance of inorganic P forms was observed. Analyses of F20 soil solutions highlighted risks of PO4 and Cu leaching. However, despite the observed increases in metal bioavailability sewage sludge applications did not lead to an increase in plant shoot concentrations (in wild plants or crop species). On the contrary, depending on the plant species, Mn and Zn tissue concentrations were within the deficiency level for most plants.     

Earthworms as biological monitors of cadmium, copper, lead and zinc in metalliferous soils

Earthworms (Lumbricus rebellus and Dendrodrilus rubidus) were sampled from one uncontaminated and fifteen metal-contaminated sites. Significant positive correlations were found between the earthworm and 'total' (conc. nitric acid-extractable) soil Cd, Cu, Pb and Zn concentrations (data log1) transformed). The relationships were linear, and the accumulation patterns for both species were similar when a single metal was considered, even though there were species difference in mean metal concentrations. Generally, the earthworm Cd concentration exceeded that of the soil; by contrast, the worm Pb concentration was lower than the soil Pb concentration in all but one (acidic, low soil Ca) site. Our observations suggest that Cu and Zn accumulation may be physiologically regulated by both species. Total-soil Cd explained 82-86% of the variability (V2) in earthworm Cd concentration; 52-58% of worm Pb and worm Zn concentrations were explained by the total-soil concentrations of the respective metals. Total-soil Cu explained only 11-32% of the worm Cu concentration. The effect of soil pH, total Ca concentration, cation-exchange capacity (CEC) and organic carbon on metal accumulation by L. rubellus and D. rubidus was investigated by multiple regression analysis. Soil pH (coupled with CEC) and soil Ca had a major influence on Pb accumulation (V2 of worm Pb increased to 77-83%), and there was some evidence that Cd accumulation may be suppressed in extremely organic soils. The edaphic factors investigated had no effect on Cu or Zn accumulation by earthworms. In the context of biomonitoring, it is proposed that earthworms have a potential in a dual role: (1) as 'quantitative' monitors of total-soil metal concentrations (as shown for Cd); and (2) as estimators of 'ecologically significant' soil metal, integrating the effects of edaphic factors (as shown for Pb).     

Bioconcentration of zinc and cadmium in ectomycorrhizal fungi and associated aspen trees as affected by level of pollution

Concentrations of Zn and Cd were measured in fruitbodies of ectomycorrhizal (ECM) fungi and leaves of co-occurring accumulator aspen. Samples were taken on three metal-polluted sites and one control site. Fungal bioconcentration factors (BCF = fruitbody concentration: soil concentration) were calculated on the basis of total metal concentrations in surface soil horizons (BCF_tot) and NH₄NO₃-extractable metal concentrations in mineral soil (BCF_lab). When plotted on log-log scale, values of BCF decreased linearly with increasing soil metal concentrations. BCF_lab for both Zn and Cd described the data more closely than BCF_tot. Fungal genera differed in ZnBCF but not in CdBCF. The information on differences between fungi with respect to their predominant occurrence in different soil horizons did not improve relations of BCF with soil metal concentrations. Aspen trees accumulated Zn and Cd to similar concentrations as the ECM fungi. Apparently, the fungi did not act as an effective barrier against aspen metal uptake by retaining the metals.     

Degradability of ethylenediaminedisuccinic acid (EDDS) in metal contaminated soils: implications for its use soil remediation

Previous research has identified ethylenediaminedisuccinate (EDDS) as a promising biodegradable alternative for persistent compounds such as EDTA for application in soil washing or enhanced phytoextraction of heavy metals. This study examines heavy metal mobilization in three polluted soils varying in soil composition, with specific attention for competitive behaviour for complexation between the various metals and major elements, such as Al, Fe, Mn, Ca and Mg. In addition, amendment biodegradability was compared between the different soil types. The selected soils included a moderately contaminated calcareous clayey soil, a dredged sediment derived surface soil with similar soil characteristics yet more heavily polluted with Cd, Cr and Zn, and a sandy soil moderately contaminated by historical smelter activity (atmospheric deposition). Biodegradability of EDDS in the three soils varied distinctly. This was mainly expressed in the duration of the lag phase prior to metal complex degradation, and not so much in the half life when degradation effectively did set in. Differences in the lag phase were attributed to differences in soil pollution. However, EDDS was fully degraded within a period of 54 d in all soils regardless of initial delay. Assessment of the cation mobilisation patterns in the three soils under study revealed that mainly Ca, Fe and Al can reduce effectiveness of heavy metal mobilisation by competition for complexation.     

Physicochemical characterisation of diesel exhaust particles: Factors for assessing biological activity

A range of microscopy and analytical techniques have been used to investigate the physicochemical properties of diluted DEP that may be important in determining its biological activity. Transmission electron microscopy demonstrated four basic categories of particle morphology: (1) “spherulites” [individual particles]; (2) “chains” or “clusters” of spherulites; (3) “spherules”, [large bodies of spherulites]; (4) “flake-like bodies”. Image analysis of TEM photomicrographs determined empirical morphological parameters (30 nm mean spherulite diameter, aspect ratio 1.5, mean particle area 0.078 μm, equivalent spherical diameter 0.23 μm, roundness 2.76) and derived parameters (0.313 μm² surface area, 3.7 μm² pg surface area per mass and 0.042 μm³ volume) of DEP. Distributions of the particle sizes by number showed 10.1% were ultrafine (<0.1 μm), 89.5% fine (0.1–2.0 μm), 0.4% coarse (>2.5 μm), but distributions based on a mass value were different (0.01% ultrafine; 52.6% fine, 47.4% coarse). In contrast, impacted DEP contained 60.87% ultrafine, 39.13% fine and 0% coarse particles by number. Field emission scanning electron microscopy of spherulites revealed smooth surfaces and flocculated spherules with large surface areas. Electron probe X-ray micro-analysis demonstrated the presence of C, O, Na, Mg, K, Al, Si, P, S, Cl, Ca along with a range of metals (Ti, Mn, Fe, Zn, Cr), that were heterogeneous in distribution. Inductively coupled plasma mass and atomic emission spectrometry identified Mg, P, Ca, Cr, Mn, Zn, Sr, Mo, Ba, Na, Fe, S, and Si as the mobile sorbed metals readily removed during sonication in water from DEP suspensions. X-ray Diffraction confirmed previous observations of the presence of nanometer sized crystallites of disordered graphite. Comparison of microscopy and analytical results between sonicated and impacted DEP revealed a physicochemical difference that must be taken into account in any toxicological investigations.     

Copper distribution in surface and subsurface soil horizons

The horizons of four natural soils were treated with Cu²⁺ in an acid medium to study the retention capacity of Cu. The possible mineralogical changes arising because of the treatment were also studied. The soil properties and characteristics with the greatest influence on the metal retention and its distribution among the different soil fractions were determined. Crystalline phases of each horizon were determined by X-ray diffraction (XDR). The morphology, structural distribution and particle chemical composition of soil samples were investigated using field emission scanning electron microscopy. Cu distribution in the different geochemical phases of the soil was studied using a sequential extraction. The treatment led to an increase in the amorphous phases and the formation of new crystalline phases, such as rouaite (Cu₂(NO₃)(OH)₃) and nitratine (NaNO₃). Cu was also found superficially sorbed on amorphous hydroxy compounds of Fe that interact with albite, muscovite and gibbsite, and also on spherical and curved particles of aluminium clays. The largest amount of Cu retained was in an exchangeable form, and the smallest amount associated with the crystalline Fe oxides and residual fraction. In the surface horizons, the predominant Cu retention process is complexation in organomineral associations, while in the subsurface horizons it is adsorption.     

Source identification and risk assessment of heavy metal contaminations in urban soils of Changsha,a mine-impacted city in Southern China

The urban soils suffered seriously from heavy metal pollutions with rapid industrialization and urbanization in China. In this study, 54 urban soil samples were collected from Changsha, a mine-impacted city located in Southern China. The concentrations of heavy metals (As, Cd, Co, Cu, Mn, Ni, Pb, and Zn) were determined by ICP-MS. The pollution sources of heavy metals were discriminated and identified by the combination of multivariate statistical and geostatistical methods. Four main sources were identified according to the results of hierarchical cluster analysis (HCA), principal component analysis (PCA), and spatial distribution patterns. Co and Mn were primarily derived from soil parent material. Cu, Pb, and Zn with significant positive relationships were associated with mining activities and traffic emissions. Cd and Ni might be affected by commercial activities and industrial discharges. As isolated into a single group was considered to have correlation with coal combustion and waste incineration. Risk assessment of heavy metals in urban soils indicated an overall moderate potential ecological risk in the urban region of Changsha.     

Vertical distribution of Cd, Pb and Zn in soils near smelters in the North of France

The analysis of the horizons of 12 soil profiles confirm occasionally significant levels of Cd, Pb and Zn contamination in the areas surrounding two lead and zinc smelters in the North of France. A pedological approach enabled the original Cd, Pb and Zn content of the horizons to be estimated, based on physico-chemical characteristics of soil unaffected by contamination. The main contamination was found in the upper 20-30 cm. Traces of Cd and Zn contamination were found at a depth of around 2 m. The mobility of the metals may be classified in the following order: Cd>Pb> or =Zn. The concentration profile of a metal seems insufficient to evaluate its movement as the metal could have been leached beyond the contaminated horizons. The depth reached by the metals increases with their concentration in the surface horizon; a decrease in pH and an increase in sand content seem to facilitate their movement. The depth reached by Zn increases with the organic carbon content in the surface horizon. Earthworm galleries act as paths via which metals migrate downwards     

Probing the distribution and contamination levels of 10 trace metal/metalloids in soils near a Pb/Zn smelter in Middle China

The horizontal and vertical distribution patterns and contamination status of ten trace metal/metalloids (Ag, Bi, Co, Cr, Ge, In, Ni, Sb, Sn, Tl) in soils around one of the largest Chinese Pb–Zn smelter in Zhuzhou City, Central China, were revealed. Different soil samples were collected from 11 areas, including ten agricultural areas and one city park area, with a total of 83 surface soil samples and six soil cores obtained. Trace metal/metalloids were determined by inductively coupled plasma–mass spectrometry after digestion by an acid mixture of HF and HNO₃. The results showed that Ag, Bi, In, Sb, Sn, and Tl contents decreased both with the distance to the Pb–Zn smelter as well as the soil depth, hinting that these elements were mainly originated from the Pb–Zn smelting operations and were introduced into soils through atmospheric deposition. Soil Ge was influenced by the smelter at a less extent, while the distributions of Co, Cr, and Ni were roughly even among most sampling sites and soil depths, suggesting that they were primarily derived from natural sources. The contamination status, as revealed by the geo-accumulation index (I _geo), indicated that In and Ag were the most enriched elements, followed by Sb, Bi, and Sn. In general, Cr, Tl, Co, Ni, and Ge were of an uncontaminated status.     

Effects of arsenic on concentration and distribution of nutrients in the fronds of the arsenic hyperaccumulator Pteris vittata L

Pteris vittata was the first terrestrial plant known to hyperaccumulate arsenic (As). However, it is unclear how As hyperaccumulation influences nutrient uptake by this plant. P. vittata fern was grown in soil spiked with 0-500 mg As kg(-1) in the greenhouse for 24 weeks. The concentrations of essential macro- (P, K, Ca, and Mg) and micro- (Fe, Mn, Cu, Zn, B and Mo) elements in the fronds of different age were examined. Both macro- and micronutrients in the fronds were found to be within the normal concentration ranges for non-hyperaccumulators. However, As hyperaccumulation did influence the elemental distribution among fronds of different age of P. vittata. Arsenic-induced P and K enhancements in the fronds contributed to the As-induced growth stimulation at low As levels. The frond P/As molar ratios of 1.0 can be used as the threshold value for normal growth of P. vittata. Potassium may function as a counter-cation for As in the fronds as shown by the As-induced K increases in the fronds. The present findings not only demonstrate that P. vittata has the ability to maintain adequate concentrations of essential nutrients while hyperaccumulating As from the soil, but also have implications for soil management (fertilization in particular) of P. vittata in As phytoextraction practice.     

Impact of soil quality on elemental uptake by,and distribution in,Colocasia esculenta (Amadumbe), an edible root

In this study the elemental distribution of selected essential (Ca, Mg, Al, Mn, Cu, Fe, Co, Cr, Zn, Ni and Se) and the non-essential (Pb, Hg and As) elements were determined in the bulb and peel of Amadumbe (Colocasia esculenta) samples from eight different sites in KwaZulu-Natal, South Africa. The concentration of Se and As in the soil and in the Amadumbe bulbs were below the detection limit of 0.09 μg g^?1. The total and bioavailable concentrations of the elements in conjunction with pH, soil organic matter (SOM) and cation exchange capacity (CEC) were determined in the soil samples from the eight sites. Statistical analysis was done to evaluate the impact of soil quality parameters on the chemical composition of the Amadumbe root. The results show accumulation or exclusion of certain elements by the bulb as evidenced by the noticeable increase or decrease of the concentrations of elements, respectively. Ca and Mg were found to be major elements in the range (2000–12000 μg g^?1), whilst Mn, Zn, Fe and Al were found to be minor elements in the range (20–400 μg g^?1). A general trend observed was that the plant favours the absorption of Zn over Cu. A positive correlation between Mg & Ca, Cu & Fe and Co & Ni was also observed. Statistical analysis revealed that the plant tended to accumulate Mg, Ca, Co, Cr and Pb whilst it excluded Hg and Fe, to a lesser extent.