Heavy Metal Concentrations In Plants Research Articles

Effect of particle size and application rate of steel (Linz-Donawitz, LD) slag on heavy metal built-up in soil and their transfer dynamics in spinach (Spinacia oleracea L.)

Linz-Donawitz (LD) slag is a solid industrial waste generated during the production of steel. In general, the amount of LD slag produced varies from 300 to 400 kg ton-1 of steel. Presently only 25 % of the steel slag, which is also rich in various macro and micro-nutrients, is being reused in India compared to 70–100 % in other countries. The present study deals with the possibility of utilizing LD slagas a nutrient rich low-cost soil conditioner in agriculture. An experiment was thus conducted to determine the effect of LD slag application at rates 0.25, 0.50 and 1 t ha-1 in two particle sizes i.e., <50 and <100 microns (µ) on spinach (Spinacia oleracea L.). Physico-chemical, biological characteristics and heavy metals in soil and latter’s transfer from soil to the foliage was also determined. The results showed that an application of LD slag @1 tha-1 and 100 µ particle size significantly improved the soil microbial count and activity of enzymes such as dehydrogenase and phosphatase while at a smaller particle size of LD slag (50 µ) @ 1 tha-1, a significant increase in the foliage yield of spinach was observed. The risk due to heavy metals present in the steel slag as evidence by indicator of heavy metal content in plants i.e. transfer factor (TF), hazard quotient (HQ) and hazard index (HI) was within the permissible range. However long-term effect of steel slag application on ecotoxicity and phytotoxicity levels must be deciphered. In conclusion the application of LD slag in spinach does not negatively impact the soil health and in fact causes an increase in the economic yield of spinach.

Impact of fly ash deposition on plants diversity, metal content, and associated risk on grazing ruminants in the vicinity of Morupule power station, Botswana

Fly ash (FA) deposition originating from power stations and unprotected dumpsites, have been found to affect plant communities, potentially causing environmental degradation and food chain contamination. An analysis of plant composition, heavy metal concentration in plants and soil within 40 kilometers of the Morupule dumpsite was conducted to evaluate the impact of FA disposal. In addition, risks to the ruminants grazing in this area, were assessed. The windward transect had significantly higher species diversity and richness than the leeward transect, especially in areas closer to the dumpsite. This could be attributed to the inability of some plants to tolerate higher concentrations of toxic metal and alkalinity in areas near the dumpsite. In this study, average concentrations in plants of Cr (546.11 mg kg−1), Mn (905.69 mg kg−1), and Cu (128 mg kg−1) were above toxicity levels of 75-100 mg kg−1 for Cr, 400 mg kg−1 for Mn, and 100 mg kg−1 for Cu. Although the quantities of these metals were above the maximum allowable daily consumption, calculations of the daily plant intake by grazing animals in this area revealed a potential danger of exposure to Cr and Cu. Particularly in areas that were nearest to the FA dumpsite, ruminants grazing on the leeward transect were more exposed to Cu than Cr toxicity. Overall, it was found that FA deposition damaged the plant community and put grazing ruminants at greater danger. However, more investigation is required to pinpoint the precise level of hazardous metals found in the grazing animals in this area.

Potential of Purslane (Portulaca oleracea L.) in Phytoremediation: A Study on the Bioaccumulation and Bio-Transfer of Cadmium, Nickel, and Copper in Contaminated Soils

As industrial and agricultural activities intensify and technology rapidly advances, soil pollution has escalated to alarming levels. The increasing contamination of agricultural areas and the crops cultivated therein has emerged as a significant contemporary issue. Phytoremediation, the use of plants to remove pollutants, is a promising method for mitigating soil heavy metal contamination. &#x0D; This study investigates the bioaccumulation capacity of purslane (Portulaca oleracea L.), a potential phytoremediator, in soils artificially contaminated with cadmium (Cd), nickel (Ni), and copper (Cu). Purslane was cultivated under controlled conditions with varying doses of Cd, Ni, and Cu. After 55 days, the plants were harvested and analysed for heavy metal concentrations in their roots, stems, and leaves. Results demonstrated a direct correlation between environmental heavy metal concentration and plant heavy metal content, with the most significant accumulation occurring in the roots. Leaf chlorophyll content was adversely affected by increased Cd, Ni, and Cu applications. The highest Cu, Ni, and Cd contents were found in the roots at 140 mg kg-1 Cu, 80 mg kg-1 Ni, and 20 mg kg-1 Cd applications, respectively. The bio-transfer coefficient (BTC), a measure of heavy metal transport from the root region to the leaves, was calculated. The BTC values ranged from 0.84-1.09 for Cu, 0.39-0.84 for Ni, and &gt;1 for Cd at the Control and 5 mg Cd kg-1 treatments. &#x0D; These findings suggest that purslane has potential for phytoremediation of heavy metal-contaminated soils, although the bioaccumulation and bio-transfer of heavy metals are dependent on the specific metal and its concentration in the soil. The study also highlights the potential risks associated with the consumption of plants grown in heavy metal-contaminated soils, as heavy metals can accumulate in different plant tissues, potentially entering the food chain.

Investigation of Heavy Metal Contents in Thyme (Thymus vulgaris) and Ginger (Zingiber officinale) Sold in Bingöl Herbalists

Objective: In our country, which is rich in medicinal plant diversity, there is an increase in heavy metal accumulation with the increase of industrial development and environmental pollution. The aim is to evaluate the health safety of heavy metal content of thyme and ginger plants, which are frequently used for therapeutic purposes, sold in herbalists. Methods: In this study, heavy metal (Cr, Fe, Co, Ni, Cu, Zn, As, Cd, Hg, Pb) levels in thyme (Thymus vulgaris) and ginger (Zingiber officinale) plant samples obtained from three different herbalists in Bingöl were determined by ICP-MS. Results: Fe, Zn, Cd and Pb levels in both thyme and ginger samples, Cr levels in thyme samples and Cu levels in ginger samples were above the safe limit values for health. In the thyme and ginger samples, Co, Ni, Cr levels in ginger samples and As levels in thyme samples were found to be in the safe range for health Conclusion: As a result; it is noteworthy that some heavy metals in medicinal plants used for therapeutic purposes in this study are above the recommended critical levels. Considering the possibility of exposure to heavy metals while consuming medicinal plants, regular monitoring of heavy metal concentrations in plants is important in order to minimize the risks that may adversely affect human health

Phytostabilization Potential of Salix alba as Biomonitors of Heavy Metals in Soil Pollution near the Erzeni Riverbank

The great sources of water pollution in Albania in the last decade are urban discharges which indicate in other sistems. The aim of this study was to evaluate the concentration of heavy metals in the soil and plant of Salix alba. Samples was collected from the Erzen riverbed. The objectives are based on assessment of the concentrations of physico-chemical characteristics heavy metals obtained from the sediment and willow (Salix alba) in Erzeni river. The presence of organic matter in soil - the willow plant - was also analyzed. The use of plants in the recuperation of contaminated soil is low cost, sustainable, and environmentally sound. Heavy metals concentration in soil range as follows: Ni (42.2–98.4 mg/kg); Cr (18.9- 34.5 mg/kg), and Pb (53.2-98.4 mg/kg). Some statistically significant differences were observed in the data on the amounts of metals accumulated in the soil, significantly more than in the data on the metal concentrations achieved in the tissues of the Salix alba plant. Heavy metal concentration in plants reach values Ni (0.9–3.54 mg/kg); Cr (0.57 - 0.89 mg/kg), and Pb (0.06 -0.19 mg/kg). Average concentrations in heavy metal plant samples were listed in the order Ni&gt; Cr&gt; Pb. The results of nickel, chromium, and lead clearly show higher concentrations in samples 0-25 cm across the range of extractors. The use of diversified plant materials is essential and optimal for the phytoremediation process. These species offer different opportunities through their metallic tolerance and accumulation of underground biomass metals for the permanent removal of these metals from the terrestrial substrate.

Physiological Response of Two Typical Plant Species under Combined Pb and Cd Stress in Bioretention Facilities

Bioretention facilities reduce stormwater runoff and pollutants, but there is a concern that plants in bioretention facilities may absorb heavy metal pollutants from stormwater runoff, which might impair the growth of the plant species. To investigate this issue, stormwater runoff containing various amounts of Pb and Cd heavy metals was used as the irrigation water in a bioretention facility. The low concentrations of Pb and Cd were 0.08 and 0.04 mg/L, and the high values were 0.68 and 0.32 mg/L. The plant heavy metal content and physiological indicators were measured. The indicators were chlorophyll content (CC), net photosynthetic rate (NPR), and transpiration rate (TR). The results showed that the changes in plant chlorophyll content (CC) were highly correlated with changes in the plants’ Pb. Low concentrations of Pb and Cd slightly inhibited the Ginkgo biloba L. and Ligustrum × vicaryi NPRs, the effect was more obvious at high concentrations and the Ligustrum × vicaryi’s NPR decreased from the initial 8.97 μmol CO2/(m2s) to 5.77 μmol CO2/(m2s) under high concentration conditions. Pb and Cd increased the Ginkgo biloba L. and Ligustrum × vicaryi’s TRs, and the effect at low Pb and Cd concentrations was more significant. Under low concentrations of Pb and Cd stress, the Ginkgo biloba L.’s TRs reached 0.63 mmol H2O/(m2s), Ligustrum × vicaryi’s TRs reached 1.30 mmol H2O/(m2s). The TRs of the two plants in the experimental groups remained high throughout the experiment, and there was no significant inhibition. The study found that Pb and Cd in stormwater runoff did affect the physiological function of species to some extent. Different plant species behaved differently in bioretention facilities, but the stormwater runoff did not lead to the death of species. Our study may provide a better understanding of the development of typical plant species in bioretention facilities.

Phytoremediation potential of indigenous plants growing in soils affected by mine activities in Gejiu City, Yunnan Province

Indigenous plants growing in mining spoils for phytoremediation have attracted great interest. To search the suitable plants, six plant species popular in the mine slag heaps of Gejiu City were collected and metal concentrations in plants and rhizosphere soils were analyzed. Results showed that the soils were greatly influenced by mine activities and heavy metal contents in plants were dependent upon those in the rhizosphere soils. However, the adaptation strategies varied among them. Bothriochloa ischcemum (Linn.) Keng and Equisetum ramosissimum Desf. had the Cr bioaccumulation factor (BAF) of 1.48 and 1.34, respectively, even though the rhizosphere soils were not contaminated by Cr. However, B. ischaemum and Agave americana Linn. showed the BAF for Pb, Zn Cu and Sn < 1.0, and Cyperus rotundus Linn. showed the similarly low BAF for Zn and Cu. Therefore, the three species had a great tolerance to phytostabilize these metals. Gymnema sylvestre (Retz.) Schult showed the translocation factor (TF) > 1.0 for Pb, Cu and Sn, so translocating these metals to the aboveground parts would be a feasible option. Similarly, Euphorbia cyathophora Murr. demonstrated the high phytotranslocate capacity for Cd and Sn, so it could be employed to remedy Cd and Sn-contaminated soils.

Estimating cadmium-lead concentrations in rice blades through fractional order derivatives of foliar spectra

Heavy metal pollution in farmland harms the environment and poses a potential risk to human health. Visible and near-infrared reflectance (VNIR) spectroscopy is a promising tool for estimating heavy metal concentrations in plants. Integer-order derivatives (including the first and second) are commonly used to pre-process VNIR data and successfully detect certain spectral signals. However, they fail to detect gradual tilts or curvatures and useful target variable information. In this study, a greenhouse experiment covering 16 pre-treatments of Cd–Pb (cadmium-lead) cross-contamination was designed to collect the VNIR data of rice blades during the late booting stage. A fractional order derivative (FOD) algorithm with increments of 0.1 was utilised to pre-process the spectra of the rice blades to explore the model performance in building relationships between Cd and Pb concentrations and leaf spectra. The results indicated that the inversion with pre-processing of integer-order derivatives was not as good as the optimal results with pre-processing of fractional-order derivatives. The R 2 and RMSE of the Cd estimation reached 0.84 and 4.69 at 0.3 rd order pre-processing, while the R 2 and RMSE of Pb were 0.49 and 191.24 at 1.4 th order pre-processing. These optimal results were better than those with pre-processing of 1 st and 2 nd derivatives, resulting in an increase of R 2 and a decrease of RMSE. These results indicated that fractional-order derivatives outperformed integer-order derivatives for pre-processing the rice blades spectra to estimate Cd–Pb concentrations. Our results demonstrated that FOD is an effective spectral processing routine for heavy metal estimation for Cd–Pb cross-contamination. • VNIR spectra of rice blades under Cd–Pb cross-contamination were measured. • Fractional order derivative (FOD) was used to analyze the spectra of rice blades. • FOD can extract more spectral details than first and second derivatives. • PLSR with 0.3 rd (for Cd) and 1.4 th (for Pb) order yielded the best prediction.

Application of Sewage Sludge in a Rice (Oryza sativa L.)-Wheat (Triticum aestivum L.) System Influences the Growth, Yield, Quality and Heavy Metals Accumulation of Rice and Wheat in the Northern Gangetic Alluvial Plain.

For a sustainable and profitable agriculture production system, balanced and integrated use of nutrients is a key strategy. In addition, partial replacement of chemical fertilizers with organics ones reduces both environmental concerns and economic costs and provides greater soil health benefits. With this hypothesis, an experiment was conducted to assess the yield and economic benefits of a rice-wheat cropping system (RWCS) as influenced by the joint application of sewage sludge (SSL) and fertilizer. The treatments comprised: without fertilizer or SSL; 100% recommended dose of fertilizers (RDF); 100% RDF + 20 Mg ha−1 SSL; 100% RDF + 30 Mg ha−1 SSL; 50% RDF + 20 Mg ha−1 SSL; 60% RDF + 20 Mg ha−1 SSL; 70% RDF + 20 Mg ha−1 SSL; 50% RDF + 30 Mg ha−1 SSL; 60% RDF + 30 Mg ha−1 SSL and 70% RDF + 30 Mg ha−1 SSL. The experiment was laid out in a randomized block design with three replications. The result of our study indicate that the highest percent increase in mean plant height i.e., ~14.85 and ~13.90, and grain yield i.e., ~8.10 and ~18.90 for rice and wheat, respectively, were recorded under 100% RDF + 30 Mg SSL ha−1 treatment compared to 100% RDF, while 70% RDF + 20 Mg ha−1 SSL produced a statistically equivalent grain yield of 100% RDF in RWCS. The application of 20 and 30 Mg SSL ha−1 along with recommended or reduced fertilizer dose, significantly increased the heavy metal content in plant and soil systems above that of 100% RDF, but this enhancement was found within permissible limits. Moreover, the reduced use of SSL i.e., 20 Mg SSL ha−1, resulted in lower heavy metal content in grain and soil than did the 30 Mg ha−1 SSL treatment, but significantly higher than in the absolute control or 100% RDF treatment. In summary, the use of 20 Mg ha−1 SSL along with 70% RDF provided a safer, profitable and sustainable option in a rice-wheat cropping system in the middle Ganegatic alluvial plain.

Enrichment Evaluation of Heavy Metals from Stormwater Runoff to Soil and Shrubs in Bioretention Facilities

Bioretention facilities with different inflow concentrations, growing media and plants were examined to determine whether the soil in these facilities was polluted with heavy metals and whether runoff had obvious toxic effects on plants. Using Beijing soil background value as the standard, the soils were evaluated by bioaccumulation index and single factor index. The results show that stormwater runoff containing Cu caused slight pollution in soils, and stormwater runoff containing Zn and Pb was not polluted. Nemerow comprehensive index evaluation revealed that the heavy metals content in the facilities containing vermiculite (a yellow or brown mineral found as an alteration product of mica and other minerals, used for insulation or as a moisture-retentive medium for growing plants) and perlite (a form of obsidian characterized by spherulites formed by cracking of the volcanic glass during cooling, used as insulation or in plant growth media) were higher than the standard. High influent concentration caused significantly higher heavy metals content in plants. While Pb accumulation in the two studied plants was the highest, Cu and Zn accumulation, which are essential for plant growth, was relatively low. The contents of the three heavy metals in the studied plants also exceeded their corresponding critical values.

Evaluation of eventual toxicities of treated textile wastewater using anoxic-aerobic algal-bacterial photobioreactor.

Water pollution is one of the major challenges and is of serious concern in the world. Toxicities generated by industrial activities severely deteriorate aquatic and terrestrial ecosystems during their uncontrolled discharge and accentuate water scarcity problems. An adequate treatment of released effluents seems to be mandatory. This study investigated the effect of synthetic textile wastewater (STWW) before and after an innovative algal-bacterial treatment occurred under anoxic-aerobic conditions on growth and mineral contents of radish plants. The health risk assessment was performed after the consumption of irrigated plants by rats. Results revealed a significant reduction in heavy metals content in plants irrigated with treated STWW, and rats fed with these plants showed normal health status. Rats fed with plants irrigated with raw STWW showed a disturbance of their homeostasis. The innovative treatment using algal-bacteria under anoxic-aerobic conditions succeeds to reduce the toxicity of raw STWW and provide an alternative water resource able to tackle water shortage.

Effect of sewage sludge-based fertilizers on biomass growth and heavy metal accumulation in plants

This study was focused on an assessment of the agronomic efficiency of organo-mineral fertilizers based on sewage sludge and possible accumulation of heavy metals in plant biomass. Fertilizers optimized for industrial crops (rape, maize, sunflower) were used in the study. The impact of fertilizers based on sewage sludge on early stage plant growth was assessed using germination tests, and the impact on further growth and development was assessed using pot trials. The germination index of cress, sorghum and mustard was in the range of 50–92% depending on the type and dose of fertilizer and on the plant tested, which corresponded to moderate to zero toxicity. The results of pot trials showed a significant impact of fertilizers based on sewage sludge on the biomass growth of selected plants. The use of fertilizers caused an increase in fresh mass of 75–138% for rape, 96–138% for maize and 23–54% for sunflower with respect to the control sample. An increase in the dose of fertilizers for rape did not significantly affect the heavy metal content in plants, except for the content of Ni. In the case of fertilizers optimized for maize and sunflower, an increase in the dose caused an accumulation of Cd, Ni, Pb and Cr in the biomass of the tested plants. However, it should be noted that the pollution level of plant biomass for all treatments was zero to medium (1.00–1.66).

Effects of Different Types of Organic Fertilizer on Biomass Yield, Bioactive Compounds and Heavy Metals Contents of Phyllanthus Niruri

This research aimed to study the effects of different types and rates of organic fertilizer on biomass yield, bioactive compounds, and heavy metals content of Phyllanthus niruri. Two types of organic fertilizers (animal-based and plant-based) with five different rates (0, 100, 200, 300, and 400 kg N ha−1) were used in this study. There was an interaction between fertilizer types and rates on biomass yield, heavy metals content, and bioactive compounds. Plants are grown with 400 kg N ha−1 of animal-based fertilizer, and plant-based fertilizer produced the highest fresh biomass. However, phyllanthin and hypophyllanthin concentrations of P. niruri were not affected by applying animal-based and plant-based fertilizers at all rates. In addition, Cd and Pb concentrations also decreased with the increasing rate of organic fertilizer and were below the Malaysia Permissible Levels (MPLs). Therefore, animal-based fertilizer at 400 kg N ha−1 was selected as the optimum rate due to its reduced heavy metal concentration in plants and higher phyllanthin and hypophyllanthin yield.

The Use of Waste Sorbents for Surface Wastewater Treatment to Intensify Plant Growth

The possibility of using sorbents from FOPS® filters, spent in the processes of purification of surface wastewater, is shown to intensify the growth of radish plants of the “French breakfast” variety. The ability of these waste sorbents, introduced into soil-ground substrates (SGS) as structure-forming additives enriched with microelements, was found to significantly stimulate the development of the root system with some slight inhibition of shoot growth. In the course of the experiments, the optimal value of the addition of sorbents spent in the processes of cleaning surface runoff (from roads) to the SGS was determined, which provides the greatest increase in the biomass of the root system of plants used as a test culture. It has been established that the accumulation of heavy metals (HMs) in the leaves and roots of a plant test culture increases with an increase in their content in the spent sorbents, but the actual concentrations of HMs in plants do not exceed the standards for their content in robust feed for animal husbandry. An assessment was made of the use of sorbents spent in water purification processes to create soil used in the reclamation of landfills for the placement of solid municipal waste, industrial dumps, road slopes, as well as in the restoration of forest resources and soil remediation.

Biochemical Responses of Medicinal Plant Tussilago farfara L. to Elevated Heavy Metal Concentrations in Soils of Urban Areas.

This study was conducted in Tyumen (Russian Federation) to establish the effects of heavy metals’ (Cu, Zn, Fe, Mn, Pb, and Cd) accumulation in soil and coltsfoot, as well as plants’ biochemical responses to such an accumulation. The mobile and acid-soluble heavy metal fractions in soils, and the heavy metal contents in plants, were determined by atomic absorption spectrophotometry. The Cu, Zn, Fe, Mn, and Pb concentrations in soils exceeded background values. Pb content at the battery manufacturing plant was above the maximum permitted concentration. The percentages of the mobile heavy metal fractions decreased in the following order: Mn > Zn > Cu > Fe. The greatest heavy metal accumulation in soils and plants was found at the battery manufacturing and metallurgical plants examined in our study. Heavy metals’ accumulation in the aboveground part of Tussilago farfara decreased in the following order: Fe > Zn > Cu > Mn > Pb > Cd. The accumulation of heavy metals stimulated the synthesis of photosynthetic pigments by 6–30%. Heavy metals provoked oxidative stress in cells, increasing the concentration of lipid peroxidation in products by up to 80%. Plant phenolics and flavonoids in the urban area of our study decreased compared to those in the control by 1.05, reaching up to 6.5 times. The change in coltsfoot catalase activity both increased and declined. Biochemical responses and heavy metal accumulation in coltsfoot from urban areas limit its use for medicinal purposes.

Soil cadmium and lead affecting biochemical properties of Matricaria chamomilla L. at different growth stages in the greenhouse and field.

Heavy metals bioremediation by medicinal plants is an important research issue, which has yet to be investigated. Matricaria chamomilla accumulation of soil cadmium (Cd, 0, 10 and 40mg/kg) and lead (Pb, 0, 60 and 180mg/kg) affecting plant biochemical properties L. at different growth stages in the greenhouse and field was investigated. The 10-kg experimental pots (located in the greenhouse and field with 80% of field capacity moisture) were filled with the treated soils, and were planted with M. chamomilla L. seeds (three replicates). Plants were sampled to determine their biochemical properties including Cd and Pb contents, pigments, proline (Pro), leaf relative water (LRW), lipid peroxidation (LX), and superoxide dismutase (SOD, EC 1.15. 1.1), and catalase (CAT, EC 1.11.1.6) activities. Soil final concentration of Cd and Pb was also determined. Heavy metal stress significantly decreased plant pigment contents; however, it significantly increased plant PRO, LRW, LX and SOD, and not CAT. Heavy metal, growth stage, growth location, and their interactions significantly affected plant heavy metal concentrations. Interestingly, although significantly higher concentration of Cd was observed in plant aerial part under greenhouse conditions, plant roots had significantly higher concentrations of Cd under field conditions, and it was reverse for Pb. Increased concentration of Cd and Pb significantly enhanced plant Pro content and the highest one was resulted by Pb3 (913.46mg/g fresh weight) significantly higher than other treatments including Cd3 (595.34mg/g fresh weight). M. chamomilla is a suitable species for the bioremediation of soils polluted with Cd and Pb.

ECOLOGICAL AND GEOCHEMICAL EVALUATION OF THE HEAVY METALS CONTENTS IN THE COMPONENTS OF THE LANDSCAPE IN KIVERTSI NATIONAL NATURE PARK “TSUMANSKA PUSHCHA”

The study presents the results of the spatial distribution of the heavy metal contents in separate components of the landscape of Kivertsi National Nature Park “Tsumanska Pushcha”. The article provides the quantitative indices of the heavy metals contents, which represent the intensity, character, and specificity of the accumulation in the soil horizons. Concentrations of the microelements fluctuate depending on the lithological type of deposits, their facies affiliation, and localization in the drainage basin. The contents of nickel, cobalt, lead, chromium, vanadium, manganese, and copper are characterized by significant divergence from their average concentrations, though it doesn’t exceed their estimated abnormal indices. Most of the studied heavy metals in the soil exceed the regional geochemical background. The biggest accumulation of copper and zinc is taking place in the forest floor, and the mineral part of the profile is lightly marked by alluvial and illuvial character. The contents of nickel, cobalt, and manganese are increasing with the depth with the accumulation of these elements, which are typical of the chemical contents of glacial deposits. The forest floor is distinctly playing the role of a barrier that prevents copper from penetration into the inner levels of occurring soil horizons. The paper defines the dependence of the heavy metal contents in plants of the national nature park on the level of technogenic load and characteristics of the soil covering of the territory. With the increase of the heavy metals in soil, they accumulate in plants. Though, with the distance from the source of contamination, the contents of the heavy metals in plants decrease by 10-20 mg/kg. The study of the most common plants, which grow on the soils of diverse mechanical contents, revealed that the plants which grow on sod-podzolic sandy soil display the biggest number of microelements, while those growing on bog soil and peat bogs. The main part of the exceeding background indices according to the elements has been found in sample areas westwards. All plants under research accumulated Mn, Cu, Cr to a maximal extent while Zn and Ti to a minimal extent, which is in accordance with elements migration of this group. The main directions of further research include the study of heavy metals distribution in diverse genetic types of the soils; definition of the standard contents of the elements in geochemical landscapes needed to identify the intensity of migration and character of elements distribution; performance of biochemical zoning.

Heavy metals in soil, plants, and associated risk on grazing ruminants in the vicinity of Cu-Ni mine in Selebi-Phikwe, Botswana.

The impact of BCL Cu-Ni mines on the surrounding environment has indicated high levels of heavy metal contamination in soil and some plant species. A comprehensive assessment of heavy metal concentration in plants, heavy metal concentration and availability in soils, and the estimates of risk associated with grazing animals in the area are presented. Exhaustive quantification of heavy metal contents in 82 plant samples revealed that some plants such as Boscia albitrunca and Boscia foetida are suitable for multi-metal phytoextraction, and others can accumulate one or two of the metals in soils or tolerate high levels of contamination. Current levels of soil contamination were manifested by acidification and high electrical conductivity, high contamination factor, and a pollution index between 8.31 and 10.79. The amount of exchangeable fractions of metals was higher than ordinary soils which is attributed to the high solubility of deposited materials on the soil surfaces. Daily intake estimates showed a possible risk associated with Pb and Cu contamination among grazing animals in the study area. Overall, the information has identified potential plants or combination of plants that could be utilized for the rehabilitation of the study area through phytoremediation. In addition, the estimates of the daily intake of the minerals due to consumption of plants in the vicinity of the BCL mines warrant for evaluation of the actual levels of heavy metals in grazing animals near the study area and in other mining areas in Botswana.

Investigation of metal concentrations in roadside soils and plants in urban areas of Amritsar, Punjab, India, under different traffic densities.

Vehicular emissions containing traces of different heavy metals are known to cause significant contamination of roadside soils and plants. The present study was conducted to investigate the heavy metal concentrations in roadside soil and plant samples (Alstonia scholaris, Nerium oleander, Tabernaemontana divaricata, and Thevetia peruviana) collected from urban areas of Amritsar city of Punjab, India, under different traffic densities. The soil and plant samples were collected in pre- and post-monsoon seasons from seven roadside sites under varying levels of traffic density and analyzed for four heavy metals (Cd, Cu, Pb, and Zn). In addition to that, total protein and carotenoid contents in plant samples were also determined. pH and electrical conductivity analysis of roadside soil samples revealed slight to strongly alkaline and non-saline nature of soil. Significant reduction in contents of total proteins and carotenoids was observed in plants collected from sites with moderate to high traffic density. The trend of heavy metal contents in plants and their corresponding soil samples was observed to be Zn > Cu > Pb > Cd for both the seasons. Index of geo-accumulation indicated moderate contamination of soil with metals analyzed, while bio-accumulation factor (BAF) showed both absorption and accumulation of metals in plants under study. The study revealed significant contamination of roadside soil and plants of Amritsar city which was linked to vehicular emissions posing potential risk to human health.

Influence of sewage sludge application on soil properties, carrot growth and heavy metal uptake

ABSTRACT A pot experiment with carrot (Daucus Carota L.) was conducted aiming to investigate some soil properties, growth and heavy metal uptake by carrot with the application of sewage sludge. The treatments used were as T1 Control (Soil only), T2 (Soil + NPK), T3 (Soil 50% and sewage sludge 50%), T4 (Soil 60% + sewage sludge 40%), T5 (Soil 70% + sewage sludge 30%) and T6 (100% Sewage sludge). The results showed that sewage sludge application significantly influenced soil pH, organic matter (OM), electrical conductivity (EC), exchangeable potassium (K) and available phosphorus (P). Heavy metals like lead (Pb), cadmium (Cd), nickel (Ni) and chromium (Cr) content in soil and plant were increased due to the application of sewage sludge. Heavy metal content in soils for different sludge treatments was lower and that in carrot samples was higher than the WHO/FAO permissible limit. The carrot was recognized by a translocation factor <1.0 for all of the heavy metals except Cd. Plant heavy metal concentrations were positively correlated with the soil organic matter content and negatively correlated with soil pH. The growth of carrot was influenced positively with sewage sludge application. Maximum fresh weight (66.3 g plant-1) was recorded in T5 treatment, and maximum dry weight (5.61 g plant-1) was in T3 treatment. The soil application of sludge improves soil fertility and enhances the better yield of carrot. Moreover, sewage sludge could be co-recycled to take simultaneously the best profit and minimize environmental pollution.