Concentrations Of Toxic Heavy Metals Research Articles

Determination of Toxic Concentrations of Heavy Metals in Selected Samples of Tobacco Products

The foremast threats to human health from heavy metals are related with use tobacco when inserted in the human body by smoking ( shisha and cigarette ) or chewable like shammah which is harm of health. The tobacco species have been collected from different places, natural or included in the installation of some of the species sold in the markets. The samples were analyzed by wet digestion method and standardized. International protocols were followed for the preparation of material and analysis of heavy metals contents and analyzed by Inductively coupled plasma spectrometer Model-Varian720 ES in center Laboratory in Meteorology, Environment and Arid Land Agriculture, and Center of Excellence in Environmental Studies, King Abdulaziz University (KAU). Results obtained using ICP-OES technique for determination of heavy metals in Tobacco products. Through this study the results were shown the heavy metals which found in tobacco samples is clearly. the objective of the study showing the concentrative the heavy metals in tobacco and compared with levels of heavy metals allowing in the World Health Organization (WHO ). What the results indicate is the seriousness of the presence of heavy metals, which cause serious diseases such as cancer and failure in most organs. The use of tobacco should be abandoned.

Identification of Toxic Heavy Metals and Trace Elements in Pesticides Used by Shallots <i>(Allium Cepa Var. Aggregatum)</i> Farmers in Brebes District, Indonesia

This study aims to identify the toxic heavy metals and trace elements in pesticides which are suspected to be a source of environmental pollution. The Neutron Activation Analysis method was used to identify and determine the concentration of toxic heavy metals and trace elements in pesticide samples. The pesticides used in this study consist of pesticides that are widely used by onion farmers in Brebes District, Central Java – Indonesia. These pesticides consist of two types (fungicides and insecticides) and in two different forms (solid and liquid). The results indicates that pesticides contain large levels of trace elements (Mg, Ti, Cl, Al, Ca, Br, Na, U, Mn, Br, La, Se, Hg, Rb, Fe, Eu, and Sb), and toxic heavy metals (As, Co, Cr, Ni, Zn, Cu, Hg). Generally, solid pesticides contain higher concentration of elements than liquid pesticides. In addition to releasing organic compounds, pesticides are also proven to be a source of certain trace elements (especially Mn, Br, Ti, Fe, Al) and toxic heavy metals (Cu, Zn, and Cr). They can affect the presence of these elements in the environment. *Corresponding author: sjuari@ugm.ac.id

Determination of Toxic Heavy Metal Contents of Some Selected Tropical Fruits Grown in Industrial Areas of Bangladesh

Fourteen tropical fruit items were collected from different industrial sites of the Dhaka and Chattogram region, Bangladesh todetermine toxic heavy metal contents. This study aimed at the assessment of the distribution of heavy metals (As, Pb and Cr) as wellas comparison of their level among different locations. The fruit items were analyzed for the quantification of the selected heavymetals using Atomic Absorption Spectrophotometer (AAS). The range of lead, chromium and arsenic in the fruit items were 1.12± 0.077 to 2.899 ± 0.013, 0 to 0.217 ± 0.005 and 0 to 0.078 ± 0.002 mg kg-1 respectively. It was revealed from the results that thelevel of toxic metals (As, Cr) in almost all fruit samples were within tolerable limit whereas the level of Pd in all of the fruit samplesexceeded the acceptable limits of WHO standard value. It was also observed from the results obtained that the concentration of themetals found in the samples from Dhaka regions were considerably higher than that of Chattogram. These metal contributors mainlyarising from anthropogenic sources including industrial wastes, automobile emissions, use of fertilizers, pesticides and herbicides inagriculture, paints, sewage and waste disposal. The extended level of these metals causing environmental pollution is hazardous sinceplants accumulate them. Subsequently, crops uptaking these heavy metals consumed by humans and animals which is detrimental tohealth. It is therefore very important that necessary actions need to be taken to monitor the level of these deleterious elements in foodplants. In decision making, planning and risk assessing this present study will play significant role.
 Dhaka Univ. J. Sci. 70(1): 22-27, 2022 (January)

A Narrative Review of Toxic Heavy Metal Content of Infant and Toddler Foods and Evaluation of United States Policy.

Excessive exposure to inorganic contaminants through ingestion of foods, such as those commonly referred to as heavy metals may cause cancer and other non-cancerous adverse effects. Infants and young children are especially vulnerable to these toxic effects due to their immature development and high ’food intake/ body weight' ratio. Concerns have been raised by multiple independent studies that heavy metals have been found to be present in many foods in the infant and child food sector. Most recently, reports from the U.S. House of Representatives Subcommittee on Economic and Consumer Policy suggest subpar testing practices, lenient or absent standards, and limited oversight of food manufacturers perpetuate the presence of these contaminants in infant and toddler foods. The aim of this narrative review is to evaluate the current state of policies in the United States designed to safe-guard against excessive heavy metal exposure and to discuss what is presently known about the presence of the so-called heavy metals; arsenic, lead, mercury and cadmium found in infant and toddler foods. PubMed was used to search for studies published between 1999 and 2022 using a combination of search terms including: “heavy metal,” “contamination,” “infant,” “toddler,” and “complementary food”.

Evaluation of the surface water and sediment quality in the Duger basin (Burdur, Turkey) using multivariate statistical analyses and identification of heavy metals.

The study aims to determine the chemical contents of the surface water of the Duger Creek and the sediments of the Duger basin, which feeds the Burdur Lake, the correlation between these contents, the potential ecological risks of these contents, the toxic heavy metal contents, and their spatial distribution by using X-ray fluorescence (XRF) spectroscopy method. The Duger basin, which has been selected as the study area, is located on the streams feeding the Burdur Lake, which has been determined as the Ramsar area in Turkey. Burdur Lake has a key role in the ecological balance due to its biological diversity, characteristic animal/plant fauna since it provides a suitable area for seasonal migration of waterfowl. Considering all these functions, the surface water and sediment quality of the Duger basin, which is located in the streams feeding Burdur Lake, is critical. In this study, elemental compositions of 20 water and 20 sediment samples collected from the Duger basin were determined by using the XRF spectroscopy method. Many elements that may have toxicological characteristics in terms of human and environmental health have been detected in the surface water and sediment samples from the Duger basin. These elements were found to have the following average values: Al (60.09mg/L), Co (3.35mg/L), Zn (3.35mg/L), Cu (2.21mg/L), Cr (0.14mg/L). It is interpreted that they may be toxic because they exceed the limits specified in WHO 2004. In this context, the surface water in the Duger basin, which feeds the Burdur Lake, must be filtered before using it as drinking water or for agricultural and livestock purposes. New strategic planning is suggested to ensure the sustainability of the basin's surface water quality.

Determination of Heavy Metals Concentration in Water and Soil at Various Locations in Lahore and their Harmful Impacts on Human and Plants life

Heavy metals poisoning of soil and water has resulted from industrial expansion in Lahore, Pakistan, creating a significant environmental hazard. As a result, monitoring the contamination of soil and water around industrial sites is critical. The fact that higher concentrations of heavy metals have a negative influence on both plants and human life and this cannot be ignored. Higher heavy metal concentrations have a direct impact on human health due to their presence in drinking water. Consumable plants and vegetables cultivated in these polluted areas may collect higher concentrations of heavy metals from soil and water via the phytoremediation process. Its worth mentioning that the accumulation of toxic metals in edible plants and vegetables also has a direct negative impact on human and animal health. The purpose of this study is to find the heavy metals concentration in the soil and ground water in the Lahore area. Five industrial zones were evaluated for water and soil throughout the research period of December 2021 to January 2022 (pre-monsoon). pH and heavy metals content measurements were performed on the collected soil and water samples. We discovered that the water had a higher pH and that the soil was heavily contaminated with significantly higher concentrations of toxic heavy metals. According to the research, there is a gangrenous influence of pollution caused by industrial waste and the surrounding environment on soil and water resources, which affects living creatures. Keywords: Environmental Pollution, Heavy Metal, Pollution, Water pollution, Soil pollution

Combination of Biochar and Phosphorus Solubilizing Bacteria to Improve the Stable Form of Toxic Metal Minerals and Microbial Abundance in Lead/Cadmium-Contaminated Soil

Biochar adsorption and microbial remediation have great potential in the field of soil remediation, but since both are stressed by high concentrations of toxic heavy metals when applied alone, combining the two may become an effective remediation method. In this study, the application effect of phosphorus-solubilizing bacteria (PSB) combined with rice husk biochar on the remediation of Pb/Cd-mixed pollution and the form differences of toxic metal were studied qualitatively and quantitatively. Compared with the contaminated soil, the combined remediation of biochar and PSB significantly increased the pH, carbon and phosphorus by 9.0%, 299.4% and 157.0%. Meanwhile, combined remediation increased the total microbial, bacterial and fungal biomass by 92.11%, 103.13% and 138.10%. This confirmed that the addition of biochar increased the soil nutrients and provided good conditions for PSB or native microorganisms to flourish. The extraction results showed that the stable form of Pb/Cd with biochar + PSB was better than that with biochar/PSB alone. Combined remediation significantly increased the acid-soluble and non-bioavailable fraction of Pb/Cd by 5/15 times and 14/5.8 times in contaminated soil. The acid-soluble and non-bioavailable fractions are the main fraction of toxic metals after combined remediation (>80%). The acid-soluble and non-bioavailable fractions were mainly carbonates and phosphate-based Pb/Cd minerals (XRD analysis). PCA and a GWB model further confirmed that the release of pH and phosphorus was the key to the passivation of Pb/Cd in a short time. Meanwhile, the combination of the biochar (phosphorus supply guarantee) and PSB (acid-soluble phosphorus function) can reduce soil acidification and improve soil nutrients, thus increasing microbial abundance in contaminated soil, even more than that in non-contaminated soil.

Preparation and characterization of fully waste-based glass-ceramics from incineration fly ash, waste glass and coal fly ash

Municipal solid waste incineration (MSWI) fly ash (FA) is a typical hazardous waste due to its high contents of toxic heavy metals, and hence its disposal has attracted global concern. In this work, it was recycled into environmental-friendly CaO–Al2O3–SiO2 system glass-ceramics via adding coal fly ash (CFA) and waste glass (WG). The effects of CaO/SiO2 ratios and sintering temperatures on the crystalline phases, morphologies, mechanical and chemical properties, heavy metals leaching and potential ecological risks of glass-ceramics were investigated. The results showed that wollastonite (CaSiO3), anorthite (CaAl2Si2O8) and gehlenite (Ca2Al2SiO7) were the dominant crystals in the glass-ceramics, which were not affected by CaO/SiO2 ratio and sintering temperature. The compressive strength increased, while the Vickers hardness and microhardness decreased as increasing the sintering temperatures from 850 to 1050 °C, which reached their maximum values of 660.69 MPa, 6.14 GPa, and 7.43 GPa, respectively. However, the increase of CaO/SiO2 ratio resulted into the reduction of the three mechanical parameters. As varying CaO/SiO2 ratio from 0.48 to 0.86, the maximum compressive strength, Vickers hardness and microhardness were 611.80 MPa, 5.43 GPa, and 6.56 GPa, respectively. Besides, all the glass-ceramics exhibited high alkali resistance of >97%. The extremely low heavy metals leaching concentrations and low potential ecological risk of glass-ceramics further revealed its environmentally friendly property and potential application feasibility.

Micro-X-ray spectral determination of the chipboard dust samples elemental composition

The paper determines the composition of dust from electrostatic precipitators of EAF gas cleaners during long-term storage in dumps in order to obtain information on classifying dust as hazardous waste. Determination of the heavy metals content in waste was performed by atomic absorption flame spectrophotometry on an AAS-1N spectrophotometer. The content of the amount total iron and the determination of its various oxidation states was carried out by redox titration with potassium bichromate in an acidic medium. A comprehensive metallo-graphic study of dust samples included macroanalysis (at x16 magnification), microanalysis of the structure of the end section of pellets from fresh dust from EAF electrostatic precipitators using optical microscopy (x 50, x 500). A detailed analysis of the microstructure of the selected samples was carried out using a JSM-6490 scanning electron microscope in the mode of secondary elastically scattered electrons. The X-ray spectral analysis of the selected samples was carried out using energy and wave spectrometers attached to a JSM-6490 scanning electron microscope. Chemical analysis of dust samples showed that there are no significant differences in the content of total iron in the presented dust samples, although there is some decrease in the depth of the dump. A stronger decrease in the transition from the surface of the dump to the depth is noted by the content of Fe3O4. All samples are magnetic, which indicates a significant content of magnetic nitrous oxide-iron oxide in the dust, most likely in an unbound state. The presence of zinc and lead impurities in the melting charge, evaporating at the operating temperatures of the furnace, leads to their oxidation by the air flow, as a result of which they can be in the final dust both in the form of free oxides and in the form of composite structures with iron oxides. It has been established that the results of the chemical analysis of electrostatic precipitator dust samples, their qualitative composition and the content of toxic heavy metals, in general (according to the average value of 10 determinations) correspond to the given technical conditions of the enterprise for this type of waste, the excess was obtained in terms of the zinc content in all considered iron-containing wastes. A distinctive feature of heavy metals present in the waste is extremely low mobility in buffer media and practical insolubility in water.

Determination of toxic heavy metal content in a whitening creams by using inductively coupled plasma-optical emission spectrometry

Determination of toxic heavy metal content in a whitening creams by using inductively coupled plasma-optical emission spectrometry

A review on bioremediation approach for heavy metal detoxification and accumulation in plants

Nowadays, the accumulation of toxic heavy metals in soil and water streams is considered a serious environmental problem that causes various harmful effects on plants and animals. Phytoremediation is an effective, green, and economical bioremediation approach by which the harmful heavy metals in the contaminated ecosystem can be detoxified and accumulated in the plant. Hyperaccumulators exude molecules called transporters that carry and translocate the heavy metals present in the soil to different plant parts. The hyperaccumulator plant genes can confine higher concentrations of toxic heavy metals in their tissues. The efficiency of phytoremediation relies on various parameters such as soil properties (pH and soil type), organic matters in soil, heavy metal type, nature of rhizosphere, characteristics of rhizosphere microflora, etc. The present review comprehensively discusses the toxicity effect of heavy metals on the environment and different phytoremediation mechanisms for the transport and accumulation of heavy metals from polluted soil. This review gave comprehensive insights into plants tolerance for the higher heavy metal concentration their responses for heavy metal accumulation and the different mechanisms involved for heavy metal tolerance. The current status and the characteristic features that need to be improved in the phytoremediation process are also reviewed in detail.

Plants from Urban Parks as Valuable Cosmetic Ingredients: Green Extraction, Chemical Composition and Activity

The research on the possibilities of using biowaste from urban green areas is scarce. In this work, four plants, widely distributed in urban parks in Central Europe (Lotus corniculatus, Medicago lupulina, Knautia arvensis and Plantago major) were extracted using eco-friendly solvents based either on aqueous cyclodextrin solutions (hydroxypropyl-β-cyclodextrin or γ-cyclodextrin) or natural deep eutectic solvents based on glycerol, betaine and glucose. Metal content was determined using total reflection X-ray fluorescence (TXRF). The content of selected metabolites was determined using UV-VIS spectrophotometric methods and HPLC. Skin-related bioactivity was assessed using tyrosinase and elastase inhibition assays. The selected plants contained metals beneficial for skin health, such as zinc and calcium, while having a low content of toxic heavy metals. The extracts contained the bioactive phenolics such as quercetin, kaempferol, luteolin and apigenin. L. corniculatus was the most potent tyrosinase inhibitor, while K. arvensis showed the most pronounced elastase inhibitory activity. The employed solvents actively contributed to the observed bioactivity. The results indicate that the biowaste obtained from urban parks represents an ecologically acceptable alternative to conventional cultivation for the preparation of ecologically acceptable, high-value cosmetic products.

Histopathological Changes in the Liver of Indian Major Carp, Catla catla Caught from Uppanar River Water, Cuddalore, India

Heavy metal contamination of Uppanar River aquatic ecosystem has been recognized as a serious pollution problem. When fish are exposed to elevated levels of heavy metals in a polluted aquatic ecosystem, they take these metals from their environment. In the present investigation, adult live specimens of edible Indian major carp, Catla catla were procured from Uppanar River, Cuddalore District from January to December 2020, Liver were processed for heavy metals estimation and histopathological studies. Liver showed accumulation of heavy metals in Catla catla. In liver the content of toxic heavy metals were found in the order-- zinc ˃ lead ˃ copper ˃ cadmium ˃ manganese˃ chromium ˃ nickel ˃ arsenic.

Comparison of different phytoremediation strategies for acid mine drainage (AMD)

Acid Mine Drainage (AMD) is a severe environmental problem that results from mining industry activities around the world. Water pollution from acid mine drainage not only damages the quality of water and soil but also affects a sustainable environment such as plants and animals in a mining area. Mining water typically has acid with highly toxic heavy metal concentrations. Remediation is one of the technologies that can be used to reduce heavy metal pollutant water from mine drainage water. There were many researches about remediation in the past, but phytoremediation has attracted various researchers’ attention. Phytoremediation is a remediation pollutants method using a plant as a media that has the advantages of being efficient, economical, and eco-friendly. The most significant important aspect for the successful phytoremediation method is a selection of the plant species. Aquatic plants have a high level of efficiency in reducing organic and inorganic pollutants in water. The efficiency of aquatic plants can be improved with innovative approaches. This review focuses on the comparison characteristic of aquatic plants in the phytoremediation method to reduce heavy metals in pollutant water. Comparison served to support innovations to improve efficiency phytoremediation application research challenge for acid mine drainage issues in the near future.

SURFACE WATER QUALITY IN KHARKIV RECREATIONAL AREAS: 2006-2020

The aim of the paper is to assess dynamics of water quality in four main recreational areas in Kharkiv and to develop recommendations for water quality improvement. Methods. Field and laboratory methods and analytical data processing. Results. The paper presents analysis of dynamics in water quality for four main recreational areas located in Kharkiv: Zhuravlevskiy Hydropark, Oleksiivskiy Lugopark, Udyanskiy Hydropark and Osnovyanske Lake. Period of study: 2006-2020, time: May-June and August-September. Average data are presented. Samples were analysed at certified Laboratory of Analytical Chemical Research of the Karazin Institute of Environmental Sciences. Laboratory data were compared with national UA standards and European ones. Conclusions were made for the following key parameters: dissolved oxygen and BOD5, total mineralization, biogenic substances content, oil products and surfactants, toxic heavy metals content. There is no specific dynamics on the pollution level. Conclusions. The following recommendations for improvement of water quality were developed: (i) to preform regular monitoring of water quality; (ii) to introduce regular and systematic control by one local authority; (iii) to improve infrastructure of recreational areas; (iv) to introduce regular cleaning of the recreational areas; (v) to install bio-WC; (vi) to install additional waste containers (preferably with separate waste collection); (vii) plant trees for better isolation from highways; (viii) to improve level of water treatment on WWTP; (ix) to create nature protected areas along rivers

Biological responses to heavy metal stress in the moss Leptodictyum riparium (Hedw.) Warnst

Leptodictyum riparium, a widely distributed aquatic moss, can both tolerate and accumulate very high concentrations of toxic heavy metals, with only slight apparent damage. Here we report the effects on photosynthetic yield, glutathione (GSH), phytochelatin (PCn) synthesis, nitrogen metabolism and cellular localization of molecules rich in SH groups in L. riparium exposed in vitro to heavy metals. We simulated the concentrations of Cu, Zn, Cd, Pb detected in Regi Lagni, Italy, one of the most contaminated freshwater sites in Southern Europe, in the laboratory to test how the moss responds to heavy metal contamination. There was a steady decrease of photosynthetic efficiency correlated with the heavy metal concentrations and ultrastructural organization. All PCn levels increased significantly as the concentration of heavy metals increased, while the GSH levels did not appear to be particularly affected. A significant increase of GDH and NADH-GOGAT activities increased with increasing heavy metal concentration. Immunoblotting analysis revealed an increase of the chl-GS2 while no significant increase was detected in the cyt-GS1. These results give insight into the molecular events underlying the metal-tolerance of the aquatic moss L. riparium exposed to environmental heavy metal concentrations.

Public health implications of heavy metals in foods and drinking water in Ethiopia (2016 to 2020): systematic review

BackgroundBesides their benefits, heavy metals are toxic, persistent, and hazardous to human health, even at their lower concentrations. Consumption of unsafe concentrations of food contaminated with heavy metals may lead to the disruption of numerous biological and biochemical processes in the human body. In developing country including Ethiopia, where untreated or partially treated wastewater is used for agricultural purposes, the problems related to the consumption foods contaminated with heavy metals may poses highest risk to human health. Therefore, this review was aimed to determine the public health implications of heavy metals in foods and drinking water in Ethiopia.MethodsThe articles published from 2016 to 2020 were identified through systematic searches of electronic databases that include MEDLINE/PubMed, EMBASE, CINAH, Google Scholar, WHO, and FAO Libraries. The data was extracted using a predetermined data extraction form using Microsoft Excel, 2016. The methodological quality of the included studies was assessed using mixed methods appraisal tool (MMAT) version 2018 and Joanna Briggs Institute Critical Appraisal tools to determine the relevance of the studies. Finally, the results were evaluated based on the FAO/WHO guidelines for foods and drinking water.ResultsA total of 1019 articles published from 2016 to 2020 were searched from various electronic databases and by manual searching on Google. Following the initial screening, 317 articles were retrieved for evaluation and 49 articles were assessed for eligibility, of which 21 studies were included in the systematic review. The mean concentration of Cr, Cd, Pb, As, Hg, Zn, Cu, Ni, Co, Fe and Mn in fruits and vegetables ranged from 2.068–4.29, 0.86–1.37, 1.90–4.70, 1.01–3.56, 3.43–4.23, 19.18–98.15, 4.39–9.42, 1.037–5.27, 0.19–1.0, 199.5–370.4, 0.26–869 mg/kg, respectively. The mean concentration Cr, Cd, Pb, As, Zn, and Fe in meat and milk ranged from 1.032–2.72, 0.233–0.72, 1.32–3.15, 0.79–2.96, 78.37–467.7, and 505.61–3549.9 mg/kg, respectively. The mean concentration of Cr, Cd, Pb, Zn, and Cu in drinking water ranged 0.0089–0.054, 0.02–0.0237, 0.005–0.369, 0.625–2.137, and 0.176–1.176 ml/L, respectively. The mean concentration of Cr, Cd, Pb, Zn, Cu, Ni, Co, Fe, and Mn in other edible cereals ranged from 0.973–2.165, 0.424–0.55, 0.65–1.70, 70.51–81.58, 14.123–15.98, 1.89–13.8, 1.06–1.59, 67.866–110.3, and 13.686–15.4 mg/kg, respectively.ConclusionThis systematic review identified heavy metals in foods and drinking water and determined their public health implications. The results of this finding imply that the majority of the studies reported high concentrations of toxic heavy metals in foods and drinking water that are hazardous to human health. Therefore, effective food safety and risk-based food quality assessment are essential to protect the public health.

Phytoaccumulation of heavy metals in native plants growing on soils in the Spreča river valley, Bosnia and Herzegovina

This study evaluated the phytoremediation potential of eight native plant species on heavy metal polluted soils along the Spreča river valley (the northeast region of Bosnia and Herzegovina). Plants selected for screening were: ryegrass (Lolium perenne L.), common nettle (Urtica dioica L.), mugwort (Artemisia vulgaris L.), wild mint (Mentha arvensis L.), white clover (Trifolium repens L.), alfalfa (Medicago sativa L.), dwarf nettle (Urtica urens L.) and yarrow (Achillea millefolium L.). All aboveground parts of selected native plants and their associated soil samples were collected and analysed for total concentration of Ni, Cr, Cd, Pb, Zn and Cu. The bioaccumulation factor for each element was also calculated. The levels of Cr (90.9–171.1 mg/kg) and Ni (80.1–390.5 mg/kg) in the studied soil plots were generally higher than limits prescribed by European standards, indicating that the soils in the Spreča river valley are polluted by Cr and Ni. Among the eight screened plant species, no hyperaccumulators for toxic heavy metals Ni, Cr, Cd and Pb were identified. However, the concentrations of toxic heavy metals in the above-ground parts of Artemisia vulgaris L. and Trifolium repens L. were significantly higher than in the other studied plants, indicating that both plant species are useful for heavy metal removal.

Soil Quality as a Key Factor in Producing Vegetables for Home Consumption—A Case Study of Urban Allotments in Gorzów Wielkopolski (Poland)

The aim of the study was to analyse the quality of soil in urban allotment gardens in the context of the production of home-grown vegetables. The study was conducted on six allotment gardens (31 individual plots) in Gorzów Wielkopolski, a medium-sized Polish city with an average level of industrialisation. The following soil characteristics were analysed: pH, electric conductivity, organic matter, organic carbon, humus, total nitrogen, C:N ratio, NH4+-N, NO3-N−, P, K, Ca, Mg, SO4−-S, Cl, Na, Fe, Cu, Zn, Mn, Ni, Cr, Cd, Pb. The analyses showed that the soils were abundant in necessary nutrients for vegetable growing. They had high content of calcium, magnesium, and phosphorus. However, the soil pH in areas of vegetable cropping was too high. The content of toxic heavy metals—cadmium (0.22–0.59 mg∙kg−1 d.m.) and lead (3.46–16.89 mg∙kg−1 d.m.)—was within the acceptable limits. Nevertheless, the chemical analysis of carrots used as test vegetables showed that the permissible limits of cadmium and lead content in their roots were exceeded. The excessive uptake of these toxic metals can be reduced by lowering the soil pH and applying organic carbon to the soil.

Bioremediation potential and lead removal capacity of heavy metal-tolerant yeasts isolated from Dayet Oum Ghellaz Lake water (northwest of Algeria).

Seven metal-resistant yeast strains were isolated and selected from Dayet Oum Ghellaz Lake water (northwest of Algeria) known as a highly polluted area by lead and cadmium. The yeast strains were screened on the basis of their resistance to seven heavy metals Hg, Cr, Cd, Pb, Cu, Zn, and Fe and characterized by molecular and phylogenetic analysis. The sequencing of the D1/D2 domain of the 26S rRNA genes revealed the affiliation of the seven yeast isolates to Rhodotorula mucilaginosa, Clavispora lusitaniae, and Wickerhamomyces anomalus species. All yeast strains were halotolerant as they were able to grow in 10-15% NaCl. The yeast isolates were highly resistant to the studied heavy metals and exhibited different tolerance according to the metal type. The highest minimum inhibitory concentrations (MIC) were observed in R. mucilaginosa RO7 and W. anomalus WO2 strains which were then selected for lead removal assays. The present study is the first to investigate the lead elimination by W. anomalus. The lead uptake was significantly affected by biomass concentration in a reverse relationship, with purification percentages estimated at 98.15 ± 0.9% and 97.046 ± 0.47% and removal efficiency of 12.68 ± 0.91 and 15.55 ± 0.72mg/g for W. anomalus WO2 and R. mucilaginosa RO7, respectively. The investigated metal-tolerant yeast strains proved to be promising candidates for bioremediation processes of heavy metals. This work amends the metal-resistant yeast bank with new strains having interesting abilities to resist to relatively high concentrations of toxic heavy metals and which can be used in the near future as low-cost biosorbents.