Toxic Elements In Plants Research Articles

Investigating the Mechanism of Potential Toxic Elements in Plants: A Review Study

Background: This study investigates the mechanism of potential toxic elements (PTEs) in plants. Materials and Methods: To obtain studies, a search was conducted in online databases, including PubMed, Scopus, and Embase until July 30, 2022. Results: A detailed understanding of the pathways and mechanisms by which PTEs can affect human health through the consumption of vegetables or grains can lead us to adopt a suitable strategy for the benefit of the public, farmers, and researchers. Conclusion: The transfer of PTEs from soil to plants takes place through multifaceted mechanisms. Bioaccumulation and toxicity of PTEs in plants are associated with plant type, soil characteristics, and PTE type.

Study of the Elemental Composition of Pectoral Species No. 2 and Its Components

INTRODUCTION. The influence of anthropogenic factors on the content of toxic elements in plants increases the need for monitoring the content of toxic elements in medicinal plant raw materials and the corresponding herbal medicinal products. In addition, studying the elemental composition of herbal medicinal products will help determine their potential in the treatment of elemental metabolism disorders (macroand micro-elementoses).AIM. This study aimed to determine the elemental composition and the heavy metal content in Pectoral Species No. 2 and its components.MATERIALS AND METHODS. The study used Pectoral Species No. 2 and its components, including common coltsfoot (Tussilago farfara L.) leaf, greater plantain (Plantago major L.) leaf, and liquorice (Glycyrrhiza glabra L., G. uralensis Fisch.) root. The samples were manufactured by Krasnogorskleksredstva JSC and purchased at Moscow pharmacies. To determine the elemental composition, the study samples were digested with concentrated nitric acid and analysed by inductively coupled plasma mass spectrometry (ICP-MS). The calibration involved using concentrations ranging from 0.5 to 1.5 times the maximum permissible concentration for each element.RESULTS. This study identified and quantified 26 elements in Pectoral Species No. 2 and its components. The content of heavy metals was within the permissible concentrations. The study established the predominant macronutrients (potassium, calcium, and magnesium), micronutrients (iron, aluminium, and strontium), and ultramicronutrients (barium, nickel, and chromium) in Pectoral Species No. 2. The authors evaluated the contributions of each herbal drug to the total element content in the medicinal product.CONCLUSIONS. Coltsfoot leaf exerts the greatest influence on the content of macro-, micro-, and ultramicronutrients in Pectoral Species No. 2. Greater plantain leaf contributes the most to the zinc, silver, and nickel content. Liquorice root has the highest strontium and molybdenum content.

Content of macro- and microelements in the plants of Artemisia annua L., A. ludoviciana Nutt. and A. austriaca L.

The purpose of this study was to investigate mineral composition of the plants species Artemisia annua L., A. ludoviciana Nutt. and A. austriaca L. Methods. Determination of the elemental composition of plant material was carried out by the X-ray fluorescence method. Results. The content of mineral elements in plants depends on their individual ability to absorb elements from the soil and accumulate them in the roots, leaves and flowers. Plant samples of three species of wormwood were grown and studied during the flowering phase under conditions of introduction in M. M. Gryshko National Botanical Garden of National Academy of Sciences of Ukraine (NBG) during 2019–2022. The qualitative and quantitative content of different macro- and microelements in the soil and plants were investigated. It was shown that aerial parts of the investigated plants accumulate the most important elements for the plants life, such as – K, Fe, Cu, Zn and Mn. Mesoelements Ca and S are present in sufficient quantities also. Elements Nb, Y, Ti, V, Cr were detected in soil, but were not determined in plants. Only A. annua plants contains Ni and Se, while A. ludoviciana and A. annua plants contain Pb. The amount of toxic elements in plants did not exceed the maximum permissible concentrations for vegetable raw materials and food products. Conclusion. Content of the main macro- and microelements was determined in the plants A. annua, A. ludoviciana and A. austriaca growing in NBG. The tendency of plants A. ludoviciana to accumulate high concentrations of iron in the roots and aerial part was observed. The obtained data will be useful for forecasting and evaluating the results of introduction of new promising species of the genus Artemisia, in breeding of new varieties of wormwood, to determine their pharmacological properties and to make a decision about the feasibility of using them in herbal tea and food products.

Accumulation of nutrients and potentially toxic elements in plants and fishes in restored mangrove ecosystems in South China.

Mangroves are highly dynamic ecosystems that offer important services such as maintaining biodiversity, filtering pollutants, and providing habitats for fishes. We investigated the uptake and accumulation of nutrients and potentially toxic elements in mangrove plants and fish to better understand the role of mangrove restoration in maintaining mangrove biota quality. In mangrove plants, the average bioconcentration factors of nutrients and potentially toxic elements were in the order P > Pb > Mn > Mg > Se > Zn > Hg > Cu > Cd > As > Co > Cr > Ni > Fe > V > Sb, where only P (all plant species) and Pb (Sonneratia apetala Buchanan-Hamilton) had a BCF > 1.0 in mangrove plants. In general, Sonneratia spp. had better performances than Kandelia candel (Linn.) Druce, Aegiceras corniculatum (Linn.) Blanco and Acanthus ilicifolius L. Sp. in terms of nutrient uptake and toxic metal(loid)s accumulation, and the best uptake capacity was found in S. apetala. Fast growth and easy adaptation make S. apetala suitable for a restored mangrove ecosystem, but continual management is needed to prevent its suppression of mangrove species diversity. The concentration of As, Cd, Hg, Cu, Cr and Pb in the mangrove sediment were 30-220% higher than the Chinese National Standard of Marine Sediment Quality Class I limits, suggesting that the sediments were unsuitable for aquaculture and nature reserves. Although a higher toxic metal(loid)s concentration in the sediment was found, the target hazard quotient (THQ) of this toxic metal(loid)s in 5 mangrove habitat fishes was <1.0, except THQ of Pb in Boleophthalmus pectinirostris Linnaeus was 1.17, and THQ of Cr in Bostrychus sinensis Lacépède was 1.12. The low THQ (less than 1.0) of mangrove habitat fishes suggested that the restored mangrove system could alleviate the bioaccumulation of toxic metal(loid)s in mangrove fish.

Determination of trace metals in vegetables using ICP-MS

Determination of trace metals in vegetables using ICP-MS

Evaluation of metal accumulation in the forage grass Brachiaria decumbens Stapf grown in contaminated soils with iron tailings.

The biggest world tailing dam rupture occurred in Brazil in 2015, releasing approximately 32 million m3 of iron tailings in the Doce River watershed, along its 660 km trajectory, reaching the Atlantic Ocean. This disaster significantly altered water and soil properties, increasing the soil metal contents, mainly iron concentration. Little is known about the concentration of toxic elements in plants grown in these areas. Brachiaria decumbens stands out as the most cultivated grass in the affected areas and is widely used for cattle grazing. This study verified the metal contents in soils and in samples of B. decumbens grown in the initial pathway of the debris flow. It was noted that the tailingdeposition altered the substrate chemically, increasing Fe by 181% and reducing Zn soil contents by 188%. However, the metal contents in the forage grass were below the toxic limit for cattle feed. In addition, the results suggest that the natural geological characteristics of the region also influenced the metal contents in plantssince those plants grown in nonaffected areas also showed high metal concentrations. The impacted area soils had a slightly basic pH, which can reduce the metal availability. Considering that, in the future, these soils would return to their natural acid state, the metal contents in plants grown in the affected regions could probably increase. Thus, long-term studies are needed to ensure the food safety of the forage production in these areas. Integr Environ Assess Manag 2022;18:528-538. © 2021 SETAC.

Trace elements concentration in soil and plant within the vicinity of abandoned tanning sites in Bangladesh: an integrated chemometric approach for health risk assessment

An effective toxicological assessment of soil-metal bioavailability and plant translocation processes is needed in view of the growing negative impact of trace element pollution on the terrestrial environment and human health. This study was conducted to assess the toxicological processes that regulate the plants’ trace element absorption into their tissues, the suitability for human use, the potential sources of trace elements, and the risk to human health, using an integrated research methodology. Soils and sweet potato plants were collected from agricultural fields near the tannery waste disposal sites of Dhaka City, Bangladesh and inductively coupled plasma mass spectrometers (ICP-MS) were used to analyze the essential and toxic elements. The mean concentrations of total elements in soil followed the descending order of Fe > Zn > Mn > Cr > Ni > Pb > Cu > As > Cd and in plant Fe > Zn > Cu > Cr > Ni > Mn > Pb > As > Cd. In the edible tissues of sweet potato, the concentrations of essential and toxic elements exceeded the maximum permissible levels, indicating not safe for human consumption. The translocation factor (TF) revealed that studied elements are more accumulated in the leaves than tubers. The enrichment factor revealed minimal to very high enrichment of essential and toxic elements in the plant parts while the contamination factor showed low to very high contamination. Considering the health risk of toxic elements from plant samples, As and Pb caused non-cancer and cancer risk on human health. However, the present results suggested that regular monitoring of these essential and toxic elements in soil and plants as well as other food materials around the abandoned tannery waste disposal sites are necessary to prevent excessive build-up of these elements in the food chain.

Jian Feng Ma.

Jian Feng Ma.

Mitigation of Chromium Toxicity in Wheat (Triticum aestivum L.) Through Silicon

Chromium (Cr) is a toxic metal usually found in soil and water, causing environmental pollution. Silicon (Si), however, has excelled in alleviating the stress caused by toxic elements in plants, and its beneficial role was mainly based on external and internal plant mechanisms. This study investigates whether and how Si influences the alleviation of Cr toxicity in wheat at the physiological and biochemical levels. The addition of Si in Cr-stressed plants significantly improved morpho-physiological characteristics, total protein, and membrane stability compared to Cr-stressed plants, suggesting that Si does have critical roles in Cr detoxification in wheat. Furthermore, Si supplementation in Cr-stressed plants showed a significant increase of Cr in roots but not in shoots compared with the plants grown under Cr stress. The addition of Si in Cr stress the raised the total chlorophyll (a and b) compared to non-treated controls. Beside this, abiotic stress indicators, such as cell death, electrolyte leakage and total soluble protein remarkably improved subjected to Si under Cr stress. These improvements are in accordance with the significant decrease of Cr in both root and shoot due to Si under Cr stress. Furthermore, Si application enhanced non-enzymatic scavenging and proline concentration to reduce Cr-induced oxidative damage in wheat. These findings reveal the role of Si on Cr detoxification in wheat and can be further implemented as a fertilization strategy.

X-Ray Fluorescence Analysis in Biology and Medicine

X-ray fluorescence analysis (XRF) is widely used when determining the concentrations of elements in various materials in biological research. Current review considers the achievements related to the features of the XRF method. X-ray fluorescence analysis in most cases is a non-destructive method that has proven its potential for measuring the concentrations of elements with a high atomic number Z in organs and tissues in vivo. The main areas of its application in biology and medicine are content determination of basic and toxic elements in plants, samples of bones, teeth, hairs, nails and tissues of vital organs, body fluids such as blood, serum, plasma, saliva, urine, etc. Usually, these studies are part of applied programs that include environmental and metabolic analyses of the population, including the influence of professional factors. The advantages of XRF are also discussed with regards to biological materials. It is noted that the form of the element in the sample practically does not affect the analysis result. In recent years, several new XRF spectrometers models have been designed, where polycapillary lenses and half lenses are used as collimating systems. This is important in the case of in vivo application of X-ray fluorescence determination of certain elements in bones and tissues. The dynamic development is typical for detectors with thermoelectric cooling. Variants of preparation of biological materials for analysis are discussed (grinding, dry or wet ashing, acid decomposition, use of suspensions in the case of XRF with TIR). The results of evaluating the interelement effects for XRF of materials of plant origin, including herbs, spices, apple leaves, birch and tomato leaves, tea, wheat, rye, rice, oatmeal, flax flour, beans, ground, and instant coffee are presented. Examples of the use of XRF in various types of forensic research are considered: poisoning, counterfeiting of drugs and food brands, dental implants, identification of remains. The review presents examples of the participation of Russian X-ray physicists in solving the problems under consideration. The list of references is 400 papers, mainly including the publications of the last 20 years.

Ionomic responses of rice plants to the stresses of different arsenic species in hydroponics.

Different ionomic profiles of plants are associated with different external stresses to which they are exposed. Investigation of ionomic variation is necessary for understanding the migration and detoxification of toxic elements in plants. In the current study, rice plants were treated with arsenite, arsenate, monomethylarsonic acid and dimethylarsinic acid in hydroponics. The ionomic responses of the rice plants to different arsenic (As) species stresses were measured and analyzed. The multielement approach is more sensitive at detecting significant variations from external environmental stresses than the consideration of several individual elements. The pairs of significant correlations between elements varied based on the rice tissues and As species used in treatment, resulting in specific correlation networks. However, some pairs of correlations existed regardless of As species treatment used in this study. Positive correlations between P and Fe were observed in rice roots treated with any of the As species, implying that P and Fe share similar biological processes. The heatmap from hierarchical cluster analysis (HCA) agreed with the principal component analysis (PCA) results in ionomic differentiation between roots and shoots. Furthermore, ionomic differences between rice plants treated with different As species were identified through PCA. This study revealed that the ionomic profiles in rice plants are sufficient to detect responses to environmental perturbations. Association studies between ionomics and genomics are necessary to further understand the potential mechanisms that promote uptake or exclusion of elements in plants.

Effects of fly ash application on plant biomass and element accumulations: a meta-analysis

Fly ash generated from coal-fired power plants is a source of potential pollutants, but can be used as a soil ameliorant to increase plant biomass and yield in agriculture. However, the effects of fly ash soil application on plant biomass and the accumulation of both nutrient and toxic elements in plants remain unclear. Based on 85 articles, we conducted a comprehensive meta-analysis to evaluate changes in plant biomass and concentrations of 21 elements in plants in response to fly ash application. These elements included macro-nutrients (N, P, K, Ca, and S), micro-nutrients (B, Co, Cu, Fe, Mn, Mo, Ni, and Zn), and metal(loid)s (Al, As, Cd, Cr, Pb, and Se). Overall, fly ash application decreased plant biomass by 15.2%. However, plant biomass was enhanced by fly ash application by 11.6–29.2% at lower application rates (i.e. <25% of soil mass), and decreased by 45.8% at higher application rates (i.e. 50–100%). Belowground biomass was significantly reduced while yield was enhanced by fly ash application. Most of the element concentrations in plants were enhanced by fly ash application, and followed a descending order with metal(loid)s > micro-nutrients > macro-nutrients. Concentrations of elements tended to increase with an increase in fly ash application rate. Our syntheses indicated that fly ash should be applied at less than 25% in order to enhance plant biomass and yield but avoid high accumulations of metal(loid)s.

Elemental Mapping of Lithium Diffusion in Doped Plant Leaves Using Laser-Induced Breakdown Spectroscopy (LIBS).

Mapping of element distributions and diffusion processes in plant tissue has great significance for understanding the systematic uptake, transport, and accumulation of nutrients and harmful elements in plants, and for studying the interaction between plants and the environment. In this work, we used laser-induced breakdown spectroscopy (LIBS) to study the elemental accumulation of Li and its diffusion in plant leaves. The spatially resolved information that LIBS offers, combined with its high sensitivity to light elements make this technology highly advantageous for the analysis of Li. Laser-induced breakdown spectroscopy mapping of Li-doped leaf samples is used to directly visualize the diffusion of Li in the plant leaf and study its distribution as a function of LiCl solution exposure time. Our findings demonstrate that diffusion of Li in plant leaves occurs though their veins (i.e., bundles of vascular tissue) and that Li concentration decreases as we move away from the LiCl exposure site. These results underline the importance of veins in transportation of toxic elements in plants, and mapping of their distribution can be instrumental in the development of possible remediation approaches for managing Li toxicity.

Determination of trace elements in plants using the direct current arc atomic-emission spectrometry

Plants connect together the atmosphere, the biosphere and the hydrosphere, participate in the migration of chemical elements and indicate an anthropogenic environmental pollution. For this reason, it is important to determine the content of a wide range of essential and toxic elements in plants. Atomic emission spectrometry with different sources of excitation of atoms is one of the most frequently used instrumental methods for determining the elemental composition of plants. Express determination of 23 essential and toxic elements in plant powders (without ashing and acid decomposition) using the atomic emission spectrometry with arc discharge (DC-arc AES) was developed. The special ways of obtaining spectra and of spectral information processing provided an increased accuracy of the analytical results in the concentration ranges from n ∙(10 -6 -10 -4 ) to 10 wt. %. The correctness of the results of the developed technique was verified by the means of the encrypted certified reference materials of the plants and matching them with the results obtained by the certified techniques of atomic emission and mass spectrometry with inductively coupled plasma. The application of the DC-arc AES technique to determine trace elements in plants from the ecologically clean and polluted areas with different landscapes, provided new analytical data for the interdisciplinary research. These data are traceable to the well-known international certified reference materials of plants. Keywords : plants, trace elements, direct current arc atomic emission spectrometry, traceability. DOI: http://dx.doi.org/10.15826/analitika.2019.23.3.011 (Russian) I.E. Vasil'eva and E.V. Shabanova Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences, Russian Federation, 664033, Irkutsk, Favorsky Str., 1A

Assessment of potentially toxic trace element contamination in urban allotment soils and their uptake by onions: A preliminary case study from Sheffield, England

Toxic trace element (TTE) contamination in urban soils may pose potential health risks, especially in cities with previous industrial activities. This study aimed to investigate soil contamination in urban allotments in Sheffield, the uptake of TTEs in autumn and spring sown onions (Allium cepa), and their potential risks on human health via consumption of the crops. Paired soil and plant samples were taken in triplicates from four private allotments to assess potentially elevated levels of lead (Pb), zinc (Zn), copper (Cu), arsenic (As), and chromium (Cr). These elements in soils exceeded the ambient background levels for England. Both Pb and As exceeded some UK and EU soil tolerable limits. Concentration factors (CF) were calculated as the ratio of trace element in the plant as compared to that in the soil, and uptake rates were in the order Zn>Cu>Cr>Pb>As. Concentrations were higher for most TTEs in spring sown onions (SSO), and had significantly higher CF (p < 0.05) for Pb and Cr than autumn sown onions (ASO), whereas the opposite was true for As. Toxic elements in plants did not exceed FAO/WHO intake limits when considering TTE content per plant and consumption rates. Human health risk assessment calculations using target hazard quotients (THQ) and hazard indexes (HI) indicated that consuming onions alone did not pose an immediate health risk.

A study of trace elements in plants of the Polar Urals and Chukotka in the search for metallophyte hyperaccumulators

The present study summarizes the results of investigations of the trace element distribution in soils and their uptake by plants of natural habitats on the ultramafic and acidic rocks of the Polar Urals and Chukotka in the Arctic Russia. Concentrations of Fe, Mn, Zn, Cu, Ni, Cr, and Co were determined by atomic absorption spectrometry in 194 plant species of 30 families and 157 soil samples. Two leaches were used for the soil – 1 M ammonium acetate (exchangeable) and 1 M HNO 3 (acid soluble); a mixture of 1.5 M HNO 3 and 3.7 M HCl was used for the plants. The levels of Fe, Cr and especially Ni in the soils on the ultramafic rocks exceeded those of soils on the acidic rocks. The mineral composition of plant species varies depending on the differences in chemical and mineralogical composition of the two soil-forming rock types. Taxon-specific features in the accumulation of potentially toxic elements in plants of these regions have been revealed for the first time. The data on the metal accumulation ability of plant species show that the species Thlaspi cochleariforme DC. and Alyssum obovatum (C.A. Mey) Turcz. ( Brassicaceae ) could be considered as Ni hyperaccumulators. These species could therefore have potential for Ni phytoextraction from contaminated soils.

Impact of Flue Gas Desulfurization Gypsum and Manure Application on Transfer of Potentially Toxic Elements to Plants, Soil, and Runoff.

There are concerns regarding the fate of nutrients from surface application of animal manure. One approach to reduce losses of P is to treat manure with industrial byproducts such as flue gas desulfurization (FGD) gypsum. However, concerns regarding potentially toxic elements contributed to the environment have arisen based on previous element-rich forms of FGD gypsum that included fly ash, whereas "new" FGD gypsum without fly ash is much lower in contaminants. This study examined the impact of FGD gypsum application on soil, plants, and runoff when applied alone or with poultry litter (PL) to soil. The study consisted of a plant response study (four rates of FGD gypsum of 0, 2.2, 4.4, and 8.9 Mg ha and four rates of PL of 0, 4.4, 8.9, and 13.4 Mg ha) and a rainfall simulation study (3.4 Mg PL ha with four rates of FGD gypsum of 0, 2.2, 4.4, and 8.9 Mg ha and controls). Plant, soil, and runoff samples were analyzed for As, Ba, Be, Ca, Cd, Ba, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Sb, Se, Tl, V, and Zn. Results indicated that FGD gypsum application would not result in increased potentially toxic elements in plants, soil, or runoff. In addition, the application of FGD gypsum significantly reduced P, As, and Fe concentrations in runoff, indicating that FGD gypsum can reduce the negative impact of manure surface application on surface water degradation.

Biomonitoring of Toxic Elements in Plants Collected Near Leather Tanning Industry

The present work aimed the study of atmospheric deposition of toxic elements near to a tannery industry by collecting black material deposited on leaf surfaces of cinnamon trees (Cinnamomum zeylanicum). Elements such as As, Ba, Cr, Cu, Fe, Ni, Pb, Sb, V, and Zn were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). For comparison purpose, black particles deposited on the leaf surface of lemon trees (Citrus lemon) collected away from the tannery industry were also analyzed. Results showed that the amount of toxic elements found in the black particles collected near tannery area was significantly higher than the amount of those measured in the comparison site. Enrichment factors (EF) of As and Cr were markedly impacted by anthropogenic emissions, whereas the other elements were moderately/slightly enriched. Cluster analysis (CA) identified the leather industry as the anthropogenic source, while As possibly comes from the wide use of pesticides and herbicides in agricultural practices. The results indicated that emissions from the leather industry and agricultural activities are the main source of pollution in this area.

Investigating the uptake and acquisition of potentially toxic elements in plants and health risks associated with the addition of fresh biowaste amendments to industrially contaminated soil

AbstractSoil contamination by potentially toxic elements (PTEs), due to rapid industrialization and urbanization, is a serious environmental concern that has been threatening both the sustainability of various agroecosystems and human health. Efforts to investigate the bioavailability, transfer, and accumulation of PTEs in the soil–plant system and their possible health consequences have almost exclusively focused in the past studies. However, there is limited evidence for increased human exposure to PTEs through dietary intake of food crop grown on contaminated soil influenced by fresh biowaste amendments (FBAs). Here, we show that FBAs addition to soil markedly (p ≤ .01) intensified human exposure to PTEs through impacts on solubility, uptake, and bioaccumulation compared with the control. In general, the risk assessment performed indicated that the hazard index values for FBAs treatments were notably higher than that of control; however, these were shown to be less than the legal limit (&lt;1). In addition, the lifetime risks of developing carcinogenicity from exposure to PTEs were far above the maximum regulatory limits (1.00E‐06), indicating that remarkable (p ≤ .01) amount of PTEs was transferred to food with the addition of FBAs. Conclusively, these results suggest that the use of FBAs to contaminated soil aggravates health risks of PTEs through wheat consumption. Further studies, which incorporate the in vitro gastrointestinal bioaccessibility, should be conducted to heighten our understanding about PTEs exposure and the risks associated with FBAs addition to contaminated soil.

Toxic Elements in Different Medicinal Plants and the Impact on Human Health.

Local medicinal plants from Madina, Saudi Arabia, are used to cure various diseases. However, some can cause adverse health effects. Five different medicinal plants were collected in the city of Madina: mahareeb (Cymbopogon), sheeh (Artemisia), harjal (Cynanchum argel delile), nabipoot (Equisetum), and kafmariam (Vitex agnus-castus). In total, four toxic elements including Al, Pb, As, and Cd were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The range of recoveries fell between 86.1 and 90.6% for all measured elements. Al levels were the highest of any of the studied elements in all plant samples, with Cymbopogon showing the highest levels. The range of concentrations of Al was 156–1609 mg/kg. Cd appeared at the lowest levels in all plants samples, with Vitex agnus-castus containing this element at the highest levels. Cd concentrations were in the range of 0.01–0.10 mg/kg. A washing process lowered the toxic elements in all plants; average % recoveries were Al (47.32%), As (59.1%), Cd (62.03%), and Pb (32.40%). The calculated human health risk assessment in one dose for toxic elements in all plants was as follows: Al (1.33 × 10−3–5.57 × 10−2 mg/kg.bw), Pb (0–8.86 × 10−5 mg/kg.bw), As (3.43 × 10−7–1.33 × 10−5 mg/kg.bw), and Cd (0–3.14 × 10−6 mg/kg.bw). Medicinal plants are a source of exposure to toxic elements. However, none of the plants in this study exceeded the daily guideline set by the WHO for any element based on conventional use by the local population. We may cautiously conclude that these medicinal plants pose no risk to users based on conventional use.