Metal Accumulation In Plants Research Articles

Efficacy of malic and tartaric acid in mitigation of cadmium stress in Spinacia oleracea L. via modulations in physiological and biochemical attributes

The increasing level of cadmium (Cd) contamination in soil due to anthropogenic actions is a significant problem. This problem not only harms the natural environment, but it also causes major harm to human health via the food chain. The use of chelating agent is a useful strategy to avoid heavy metal uptake and accumulation in plants. In this study, randomized design pot experiment was conducted to evaluate potential role of malic acid (MA) and tartaric acid (TA) foliar spray to mitigate Cd stress in Spinacia oleracea L plants. For Cd stress, S. oleracea plants were treated with CdCl2 solution (100 µM). For control, plants were given distilled water. One week after Cd stress, MA and TA foliar spray was employed at concentration of 100 and 150 µM for both. The results of this study revealed that Cd stress (100 µM) significantly reduced growth attributes, photosynthetic pigments and related parameters and gas exchange attributes. Cadmium stress also stimulated antioxidant defense mechanism in S. oleracea. Cd stressed plants had elevated levels of Cd metal ions in root and consumable parts (i.e. leaves) and caused severe oxidative damages in the form of increased lipid peroxidation and electrolytic leakage. MA and TA supplements at both low and high levels (100 and 150 µM) effectively reversed the devastating effects of Cd stress and improved growth, photosynthesis and defense related attributes of S. oleracea plants. These supplements also prevented excessive accumulation of Cd metal ions as indicated by lowered Cd metal contents in MA and TA treated plants. These findings demonstrated that MA and TA treatments can potentially reduce Cdl induced phytotoxicity in plants by reducing its uptake and enhancing photosynthesis and defense related parameters.

Effect of Biochar-Based Organic Fertilizers on the Transport and Accumulation of Heavy Metals in Soil and Plants

Anaerobically digested digestate is mostly used as organic fertilizer, but there is still a potential risk of heavy metal pollution. Biochar and bio-organic fertilizer through passivation can effectively reduce the mobility of heavy metal ions in soil, with the strong adsorption capacity of heavy metals, and are widely used in soil remediation. In this study, digestate as raw material supplemented with biochar was applied to simulated heavy metal-contaminated soil, and its effects on heavy metal content and the transformation of forms in soil and crop systems were systematically investigated. The application of biochar-based organic fertilizer to simulated heavy metal-contaminated soils resulted in large differences in the morphological distribution of heavy metals, which was reflected in a significant decrease in the content of heavy metals in the weakly acid-extractable state and an increase in the content of heavy metals in the residue state, and promoted the transformation of soil heavy metals from the weakly acid-extractable state to the residue state. There were differences in the accumulation of heavy metals in the above ground and below ground parts of cabbage, and Cu, Zn, Cd, and Pb were mainly accumulated in the below ground parts of the plants. The present study offers an effective methodology for the remediation of soil and plant contamination by a range of heavy metals (Cu, Zn, Cd, and Pb), from the weak acid extraction stage to the residue stage. This approach is of particular significance for the advancement of sustainable agriculture and environmental remediation.

Ecotoxicity of Biodegradable Microplastics and Bio-based Microplastics: A Review of in vitro and in vivo Studies.

As biodegradable and bio-based plastics increasingly replace conventional plastics, the need for a comprehensive understanding of their ecotoxicity becomes more pressing. This review systematically presents the ecotoxicity of the microplastics (MPs) from different biodegradable plastics and bioplastics on various animals and plants. High doses of polylactic acid (PLA) MPs (10%) have been found to reduce plant nitrogen content and biomass, and affect the accumulation of heavy metals in plants. Their phytotoxicity becomes more pronounced when blended with polybutylene adipate terephthalate (PBAT) MPs. Polyhydroxybutyrate (PHB) and polybutylene succinate (PBS) MPs show lower phytotoxicity than PLA MPs. At high doses, PLA and PHB MPs may cause dose-dependent developmental toxicity to aquatic organisms. Nano-PLA could induce oxidative stress and genetic damage in insects, indicating its toxicity could be size-dependent and affected by weathering. PBAT MPs have been observed to affect plant growth at lower concentrations (0.1%) than PLA MPs, while polycaprolactone (PCL) affected seed germination only at high temperatures. PCL MPs and extracts could also cause developmental and reproductive toxicity, alter metabolisms, and induce oxidative stress in aquatic organisms at high concentrations. Polypropylene carbonate (PPC) ( > 40 g/kg) MPs have caused earthworm behavioral changes. Non-biodegradable bioplastics are potentially toxic to embryos, larvae, immune systems, reproductive systems, and endocrine systems of animals. However, it is important to note that toxicity studies are still lacking for biodegradable and bio-based plastics, particularly PHB, PBS, PCL, PPC, starch-based, and non-biodegradable bioplastics. More research into the MPs of these plastics is essential to better understand their ecotoxicity and applicability.

Molecular characterization of Pleiotropic Drug Resistance (PDR) genes involved in tolerance of cadmium in peanut (Arachis hypogaea L.)

Peanut (Arachis hypogaea L.) is one of the most important oil crops worldwide. Cadmium (Cd), a heavy metal that is nonessential and toxic, has the potential to significantly impacted the quality and safety of peanut. Despite the known importance of Pleiotropic Drug Resistance (PDR) genes in heavy metal accumulation and transport in plants, there is a lack of comprehensive research on the systematic identification and functional characterization of AhPDRs in peanut. In this study, a total of 38 AhPDR genes were discovered within the peanut genome. Among these, AhPDR24, AhPDR30, and AhPDR33 displayed notable variations in expression levels in response to Cd stress. Particularly noteworthy was the observation that AhPDR33, localized in the plasma membrane, exhibited a significant increase in expression (approximately 3.8-fold) and heightened promoter activity (approximately 4.1-fold) following exposure to Cd (75 μM CdCl2). Furthermore, the study found that the overexpression of AhPDR33 in Arabidopsis resulted in increased root elongation and decreased Cd accumulation (approximately 0.42-fold) compared to wild-type plants. This suggests that AhPDR33 may have a beneficial role in facilitating Cd efflux and tolerance in plants. Additionally, transient silencing of AhPDR33 in peanut demonstrated its positive regulation of Cd tolerance through the promotion of reactive oxygen species (ROS) scavenging and membrane permeability reduction. These findings contribute to the understanding of the molecular mechanisms involved in AhPDR33-mediated Cd tolerance and detoxification in peanut. Furthermore, this study provides comprehensive information to understand the AhPDR gene family, its features, and its expression, which will hold a promising utility as an excellent candidate in the genetic improvement of peanut Cd stress tolerance.

Metallurgical Waste for Sustainable Agriculture: Converter Slag and Blast-Furnace Sludge Increase Oat Yield in Acidic Soils

The study is the first to examine the combined use of blast-furnace sludge as a source of microelements and converter slag as a soil-deoxidizing agent in oat (Avena sativa L.) cultivation in sod-podzolic soils. It has been established that blast-furnace sludge is a highly dispersed waste, which contains about 50% iron, 7% zinc, and a small amount of calcium, silicon, magnesium, aluminum, and sulfur. Hazardous components such as lead, arsenic, etc., are not detected. Converter slag comprises porous granules up to 3 mm in size, consisting mainly of calcium compounds (CaO, Ca(CO)3, CaSiO3, CaFe2O4) and a small amount of Mn, Al, and Mg trace elements. In a laboratory experiment, blast-furnace sludge increased the germination of oats by 5–10%, regardless of the addition of a deoxidizer (slag), but at the same time suppressed the growth of stem length by a maximum of 18% at 1 g∙kg−1. The addition of slag raised substrate pH and increased the index by 8% at a sludge concentration of 0.1 g∙kg−1. Root length in deoxidizer-free variants increased by 50–60% and with the addition of slag by 27–47%. Root dry mass also increased under the addition of sludge by 85–98%; however, the addition of slag reduced the indicator to the control level. In a field experiment with the combined application of waste, an increase in yield by more than 30% was shown. When soil was treated with slag and sludge, the height of plants increased by an average of 18%. It should be noted that the introduction of waste did not affect the quality of the grain. The use of slag increased the lead content in the soil, which is probably due to the sorption properties of calcium compounds in the slag, since lead was not found in the analyzed waste. Presumably, lead is sorbed by slag from the lower soil horizons, concentrating and immobilizing it in the upper layer. This version is supported by the absence of lead accumulation in straw and oat grain. The zinc-containing sludge increased the content of this element by 33% in the soil, as well as by 6% in straw and by 14% in grain. Thus, we found that the studied metallurgical wastes can be used as nutrients for agriculture, both individually and jointly. Overall, the proposed approach will contribute both to reducing the amount of accumulated waste and to improving the efficiency and sustainability of agricultural production and CO2 sequestration. However, the features of the accumulation of heavy metals in soil and plants under the influence of the analyzed types of waste require more in-depth study, including within the framework of long-term field experiments.

Metal Accumulation of Plants in a Nickel Laterite Mine and Their Phytoremediation and Phytomining Potential

Metal Accumulation of Plants in a Nickel Laterite Mine and Their Phytoremediation and Phytomining Potential

Engineered nanomaterials reduce metal(loid) accumulation and enhance staple food production for sustainable agriculture.

Metal(loid) contaminants in food pose a global health concern. This study offers a global analysis of the impact of nanomaterials (NMs) on crop responses to metal(loid) stresses. Our findings reveal that NMs have a positive effect on the biomass production of staple crops (22.8%), while showing inhibitory effects on metal(loid) accumulation in plants (-38.3%) and oxidative damage (-21.6%) under metal(loid) stress conditions. These effects are influenced by various factors such as NM dose, exposure duration, size and composition. Here we introduce a method using interval-valued intuitionistic fuzzy values by integrating the technique for order preference by similarity to an ideal solution and entropy weights to compare the effectiveness of different NM application patterns. These results offer practical insights for the application of NMs in similar multi-criteria decision-making scenarios, contributing to sustainable agriculture and global food safety.

Synergistic effects of tree-herb intercropping on the phytoremediation efficiency of cadmium and lead contaminated soil

Tree-herb intercropping has emerged as an effective strategy for the remediation of soil contamination. In this study, the effects of intercropping willow with herbaceous plants Lolium perenne L., Iris lactea Pall. and Bidens pilosa L. were investigated on the phytoremediation of Cd- and Pb-contaminated soil. After a 90-day of cultivation, the results showed that intercropping stimulated the phytoremediation efficiency through increased metal accumulation in plants. Intercropping caused a significant (p < 0.05) increase in willow biomass ranging from 48.07 % to 95.58 % by promoting photosynthesis activities and antioxidant responses. Metal contents in willow leaves and roots were also observably (p < 0.05) enhanced, indicating a beneficial effect in tree-herb intercropping systems. The biomass and metal accumulation of I. lactea Pall. and B. pilosa L. decreased due to competitive interactions with willow in the intercropping treatments. However, intercropping with willow (p < 0.05) significantly increased the Pb contents of L. perenne L. Intercropping improved the absorption of bioavailable fractions of Cd and Pb by willow and herbs in comparison to the monoculture. The decrease in soil Cd contents was partly due to the chemical changes induced by root exudates, which enhanced the transfer of Cd from the soil to the plants. Willow showed a tendency for Cd accumulation, whereas herbs exhibited Pb accumulation, reflecting the complementarity of metal accumulation in tree-herb intercropping patterns. Intercropping willow with B. pilosa L. was found to be an effective method for the remediation of Cd-contaminated soil, whereas the combination of willow with L. perenne L. proved suitable for the Pb-contaminated soil. These findings might support the potential of tree-herb intercropping as an effective strategy for enhancing the phytoremediation of contaminated soils.

Genome architecture of the heavy metal tolerant and accumulator Hirschfeldia incana: Insights from genome sequencing, assembly, and comparative analysis

Hirschfeldia incana L., a member of the Brassicaceae family commonly found in Mediterranean regions, is known for its capacity to withstand and accumulate heavy metals, particularly lead (Pb) both in soil environments and hydroponic systems. This plant has been used as a model to study plant responses to heavy metals. Nonetheless, the molecular mechanisms underlying its tolerance and heavy metal accumulation are not fully understood, partly because of the limited knowledge about its genome. In this study, the genome of H. incana was sequenced, assembled, characterized, and annotated. Approximately 8.6 Gpb of data were generated using Oxford Nanopore Technology (ONT), resulting in a genome assembly of 390 Mb, comprising 5196 contigs with an N50 exceeding 131 kb. The genome had a BUSCO score of 97.2 %, with 38,454 genes and a repetition content of 38.25 %. Subsequently, the assembled genome was annotated using several databases including GO, InterPro, MetaCyc, PANTHER, Pfam, Reactome, SUPERFAMILY, and KEGG. This annotation yielded 22,661 GO terms and 143 KEGG maps. A comparative genomic analysis between H. incana and six Brassicaceae species (five hyperaccumulators of heavy metals and one non-hyperaccumulator) was also conducted. This analysis revealed that H. incana shares a substantial proportion of orthologous genes (89.7 % of orthogroups) with six Brassicaceae species. The generated phylogenetic tree suggests that H. incana is closely related to B. juncea, B. napus, and B. oleracea, indicating a common ancestry and potentially shared genetic factors contributing to hyperaccumulation in these species. Moreover, the copy number of twenty-nine genes involved in heavy metal tolerance and accumulation mechanisms in H. incana and six brassicaceae were assayed. This analysis revealed that H. incana and other hyperaccumulator species possess a higher copy number of genes related to heavy metal tolerance than the sensitive plant A. thaliana. Notably, the variation in gene copy numbers highlights their potential role in the adaptation of H. incana to heavy metal stress. This study provides a comprehensive genomic framework that enhance our understanding of H. incana adaptation to heavy metal stress, and offers valuable data for further genomic investigations of the molecular mechanisms of heavy metal tolerance and accumulation in plants.

Accumulation and Distribution of Heavy Metals in Soils and Medicinal Plants in the Impact Zone of Novocherkassk Power Station

Accumulation and Distribution of Heavy Metals in Soils and Medicinal Plants in the Impact Zone of Novocherkassk Power Station

Elemental composition and potential toxicity of the riverine macrophyte Podostemum ceratophyllum Michx. reflects land use in eastern North America

Land use influences surface water quality, often alleviating stoichiometric constraints on primary production and altering biogeochemical cycling. However, land use effects on nutrient content and potential trace metal accumulation in aquatic plants remain unclear, and high concentrations of metals and altered nutrient ratios could impact the health of herbivores and detritivores. We tested for land use effects on nutrient and trace metal accumulation in a widespread riverine macrophyte, Podostemum ceratophyllum, collected from 91 locations from Georgia to Maine, USA in 2014–2016. We quantified carbon (C), nitrogen (N), phosphorus (P), their molar and mass ratios, N and C stable isotopes, and 17 additional elements in dried plants collected from each location to estimate relationships between plant tissue content and watershed land use, which we quantified as agriculture, forest, and development. Decreasing forest cover was correlated with increasing δ15N, Mg, Mn, and P in Podostemum tissue. Increasing urban development was correlated with increasing δ15N, Mg and P, while increasing agriculture was correlated with a decrease in C: P and the concentrations of multiple metals, along with increases in P, Mg and δ15N. Decreases in ratios of N: P and C:P with increasing agriculture and urban development in the watershed indicate more rapid P storage relative to C and N in plant tissue, and increased resource quality of the plant to consumers in these watersheds. We also observed potentially toxic dietary concentrations of some trace metals (B, Cd, Tl, Zn) in plant tissue which could be related to the plant's natural herbivory defense system or to land use. We conclude that land use influences the elemental composition of P. ceratophyllum, and potentially the quality and toxicity of the plant to herbivores and detritivores in eastern North American rivers.

Assessing Heavy Metal Accumulation in Urban Plants: Implications for Environmental Health and Traffic-Related Pollution in Al-Diwaniyah City, Iraq

This study aimed to compare the ability of five plant species, including (Conocarpus erectus, Acacia sensu lato (s.l.), Melaleuca viminalis, Dodonaea viscosa and Lantana camara) to absorb and accumulate heavy elements in their tissues, which were grown in the central islands in the city of Diwaniyah. This included areas of street in front of the medical college, Umm Al Khail First Street, Umm Al-Khail Street, near Abbas Attiwi Bridge, Al-Adly Street in the Euphrates District, and Clock Field Street, respectively. Results showed that soil samples S1 and S3 were contaminated by Pb, and the rest of the sites were contaminated with nickel only. This indicates through the table findings a rise in these heavy metals’ concentrations with a rise in traffic momentum. Thus, the Pb concentrations in the growing plants’ shoot parts with respect to this research had surpassed the allowed critical limit of 5.00 mg.kg-1 dry matter, in which the highest value was recorded at the site with respect to S3 as well as S2. Meanwhile, the findings indicate that Cd concentrations in S3 and S1 had increased and exceeded the allowable limit of 0.20 mg.kg-1 dry matter. In the meantime, the nickel concentrations were within the permissible limits of 67.90 mg.kg-1 dry matter. The Zn concentration exceeded the permitted limits of 60.00 mg.kg-1 dry matter except for plants (Acacia s.l. and Lantana camara) in sites S5 and S2. The results confirmed that the values of Heavy Metals Bioaccumulation Coefficient (BAC) for most of the study elements had recorded the highest value in the Dodonaea plant for Zn, Cd, and Pb, except for Ni. It was more accumulated in the Melaleuca viminalis plant, which indicates the superiority of the Dodonaea plant in accumulating Pb, Cd, and Zn over the rest of the study plants, as they took the following order: Lantana camara &lt; Acacia s.l. &lt; Conocarpus erectus &lt; Melaleuca viminalis &lt; Dodonaea viscosa. The best plants accumulated nickel in the following order: Acacia s.l. &lt; Lantana camara &lt; Conocarpus erectus &lt; Dodonaea viscosa &lt; Melaleuca viminalis.

Habitat-specific allocations of elements in Atriplex lentiformis seeds indicate adaptation to metal toxicity.

Self-sustaining vegetation in metal-contaminated areas is essential for rebuilding ecological resilience and community stability in degraded lands. Metal-tolerant plants originating from contaminated post-mining areas may hold the key to successful plant establishment and growth. Yet, little is known about the impact of metal toxicity on reproductive strategies, metal accumulation, and allocation patterns at the seed stage. Our research focused on the metal tolerant Atriplex lentiformis. Specifically, we examined the effects of toxic metal(loid) concentration in soils on variability in its reproductive strategies, including germination patterns, elemental uptake, and allocation within the seeds. We employed advanced imaging techniques like synchrotron X-ray fluorescence microscopy (2D scans and 3D tomograms) combined with inductively coupled plasma mass spectrometry to reveal significant differences in metal(loid) concentration and distribution within the seed structures of A. lentiformis from contrasting habitats. Exclusive Zn hotspots of high concentrations were found in the seeds of the metallicolous accession, primarily in the sensitive tissues of shoot apical meristems and root zones of the seed embryos. Our findings offer novel insights into phenotypic variability and metal tolerance and accumulation in plants from extreme environments. This knowledge can be applied to enhance plant survival and performance in land restoration efforts.

Comprehensive assessment of heavy metal contamination in soil-plant systems and health risks from wastewater-irrigated vegetables

A research study examined the origins, human health impacts, and risks associated with pollutants in vegetables grown in soil irrigated with wastewater. The study analyzed 164 samples from water sources, irrigated soil, and harvested vegetables for eight heavy metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) using atomic absorption spectrophotometry. The focus was on the potential health effects of consuming heavy metal-contaminated vegetables grown in wastewater-irrigated soil. The findings revealed significant accumulation of heavy metals in soil and plants from Mianwali, Pakistan, posing potential health risks to consumers. When compared to vegetables produced with freshwater irrigation, the concentration levels of heavy metals in the soil irrigated with untreated wastewater were significantly greater (P≤0.001) and above the recommended limits set by the World Health Organization (WHO). The results showed that heavy metals in the soil had significantly increased, and crops had subsequently absorbed these metals. Produce raised in soil watered with wastewater showed higher levels of heavy metals than the US Environmental Protection Agency (EPA) and the WHO recommended. Among the veggies, lead (Pb) and cadmium (Cd) were found to have higher Hazardous Quotient Indices (HRIs) than one. This indicates that both adults and children may have been exposed to dangerous levels of these metals. Additionally, for Brassica oleracea, Raphanus sativus, and Spinacia oleracea, nickel (Ni) surpassed HRIs larger than 1, indicating a significant health risk connected to these veggies' ingestion.

Heavy Metal Accumulation in Soil and Plants Using Municipal Solid Waste Compost in Variable pH Conditions

ABSTRACT Municipal solid waste composts (MSWC) are extensively utilized as organic soil conditioners and fertilizers in agricultural fields across many countries. However, the use of MSWC can lead to heavy metal pollution in soil and plants, which may adversely affect plant growth. This study examined the impact of MSWC on the heavy metal content in plants and soil across various pH levels. The experiment was conducted in a pot setting with three replications. The research findings indicated that MSWC application increased the levels of copper (Cu) and zinc (Zn) in soils but had no significant effect on lead (Pb), nickel (Ni), manganese (Mn), and iron (Fe) levels. Additionally, increases were observed in the Cu, Zn, and Fe content in plants, while Pb and Ni content remained unchanged. Cu, Zn, and Fe are essential for plant growth, and their enhancement in both soil and plants is a direct result of their relatively high presence in the MSWC used. The soil-plant transfer coefficients show that the transfer of heavy metals from soil to plants is highest under acidic conditions, indicating that the heavy metal content in MSWC can vary depending on soil pH and application rate. Therefore, it is crucial to carefully analyze and evaluate the heavy metal contents of soil and compost samples before employing MSWC in agricultural fields.

Heavy metal accumulation in the phytomass of plants in the Bolshoy Yugan River valley, Surgut District, Khanty-Mansi Autonomous Okrug–Yugra

Processes of heavy metal accumulation in plants are increasingly attracting research attention due to the high toxicity of such substances. The pollutants accumulated in the aerial (green leaves, stems, inflorescences) and underground (roots) mass of plants cause oxidative stress associated with the production of reactive oxygen species. In this work, we investigate the accumulation of heavy metals (nickel, lead, chromium, and cadmium) in the aerial mass of plants growing in the Surgut district of Khanty-Mansi Autonomous Okrug–Yugra. In total, leaves from 15 plant species widespread in the studied area were collected for elemental analysis by atomic absorption spectroscopy. About 6–7 mg/kg of nickel was found in the green mass of reed canary grass and heal-all (Prunella vulgaris), which exceeds significantly the nickel amount in the aerial mass of сouch grass, marsh bedstraw, and broadleaf plantain. The aerial parts of reed canary grass and broadleaf plantain were found to accumulate more than 4 mg/kg of lead, while those of bladder sedge, сouch grass, and marsh bedstraw accumulate about 2–3 mg/kg of chromium. More than 2 mg/kg of cadmium was found in сouch grass. The results obtained were used to compile series of accumulation of elements in the aerial parts of floodplain plant species. The content of the studied heavy metals in the aerial phytomass of all studied plants, except for сouch grass, ranges within standard values, corresponding to their maximum permissible concentrations.

How does silicon alleviate Cd-induced phytotoxicity in barley, Hordeum vulgare L.?

Toxic heavy metal accumulation in edible plants has become a problem worth worrying about for human health. Cadmium is one of the most toxic metals presenting high bioavailability in the environment. The main route of transfer of Cd to humans is the consumption of contaminated food which suggests that reducing of Cd absorption by plants could reduce this risk. In this context, it was suggested that silicon supply would be able to limit the transfer of Cd to the plants. Thus, this work evaluated the effects of 0.5 mM Si on Cd absorption and accumulation in barley (Hordeum vulgare L.). Plants were grown hydroponically for 21 days in the presence of 0 and 15 μM Cd2+ combined or not with 0.5 mM Si. Analyses were related to growth and photosynthesis parameters, Cd accumulation in organs and Cd subcellular distribution in the shoots. Results showed that, under Cd alone, plants showed severe toxicity symptoms as chlorosis and necrosis and produced significantly less biomass as compared to control. 0.5 mM Si in the medium culture significantly reduced Cd-induced toxicity by mitigating symptoms and restoring growth, photosynthesis, and nutrition. Si also induced a significant reduction of Cd concentration in plants and changed its sub-cellular compartmentalization by enhancing fixation to cell walls and reducing the Cd concentration in the cytoplasmic and organelles fractions. These data suggest that the application of Si could significantly increase Cd tolerance and reduce the risk of the Cd accumulation in edible plants.

Meta-analysis reveals the combined effects of microplastics and heavy metal on plants

The combined pollution of microplastics and heavy metals is becoming increasingly serious, and its effects on toxicology and heavy metal accumulation of plants are closely related to crop yield and population health. Here, we collected 57 studies to investigate the effect of microplastics on heavy metal accumulation in plants and their combined toxicity. An assessment was conducted to discover the primary pollutant responsible for the toxicity of combined pollution on plants. The study examined the influence of microplastic characteristics, heavy metal characteristics, and experimental methods on this pollutant. The results showed that combined toxicity of plants was more similar to heavy metals, whereas microplastics interacted with heavy metals mainly by inducing oxidative stress damage. Culture environment, heavy metal type, experimental duration, microplastic concentration and microplastic size were the main factors affecting heavy metal accumulation in plants. There was a negative correlation between experimental duration, microplastic concentration and microplastic size with heavy metal accumulation in plants. The interactions among influencing factors were found, and microplastic biodegradation was the core factor of the strong interaction. These results provided comprehensive insights and guiding strategies for environmental and public health risks caused by the combined pollution of microplastics and heavy metals.

Environmental microplastic interact with heavy metal in polluted soil from mine site in the North of Tunisia: Effects on heavy metal accumulation, growth, photosynthetic activities, and biochemical responses of alfalfa plants (Medicago saliva L.)

As emerging persistent pollutants, microplastic (MPs) pollution attracted increasing attention worldwide since it is posing several environmental concerns. MPs interact with heavy metals in soil and may provoke damages on soil properties and ultimately impaired plants and human health. The present study aims to evaluate alfalfa plants (Medicago sativa) response after exposure to heavy metal polluted soils from mine site in the North of Tunisia in presence of environmental microplastic. For that, soils were sampled from two sites of Jebel Ressass mine in addition to a control soil. Plants were exposed to the three soils in presence of two increasing rates of microplastics D1 (1 mg/kg of soil) and D2 (100 mg/kg of soil) for 60 days. After harvest, agronomic parameters, chlorophyll content as well as heavy metal accumulation in plants were analyzed. Furthermore, oxidative status was evaluated in terms of malondialdehyde accumulation (MDA), catalase (CAT) activities and glutathion-S-transferase (GST). Overall, our finding highlights that MPs disrupted agronomic parameters and the photosynthetic activities of alfalfa plants. Additionally, our results revealed that the presence of MPs in polluted soils cause an increase on heavy metal accumulation in alfalfa shoots. Biochemical analyses demonstrated that the combined exposure to MPs and heavy metal induced oxidative stress in alfalfa plants by increasing CAT activity and MDA accumulation. The present investigation highlights the ecological risks of microplastics in terrestrial environment.

Phytoremediation potential and vegetation assessment of plant species growing on multi-metals contaminated coal mining site

This study aims to evaluate the plant species potential to accumulate, concentrate and translocate the heavy metals around the coal mining contaminated site with heavy metals at Harnoi, Abbottabad. The phytosociological surveys involve the systematic study of plant communities within the particular area to show their composition, structure and distribution showed that the contaminated coal mining-associated area was poor in vegetation. Among these, 11 plant species with higher important values (IV) are collected with associated soil and analyzed for the total concentrations of Cadmium (Cd), Copper (Cu), Chromium (Cr), Lead (Pb) and Nickel (Ni) using Atomic Spectrophotometer. The phytoremediation indices (BAF, BCF, TF and TI) were used to evaluate the multi-metals hyperaccumulator and stabilizer plant species. Dodonaea viscosa was evaluated as multi-metals (Cd, Cu and Ni) stabilizer. While the Ajuga bracteosa and Sonchus espera, Sisybrium officinale and Platango ovata stabilize Cd and Cr respectively. The other plant species that can stabilize as single heavy metal are Ajuga bracteosa and Sonchus espera (Cd), Sisybrium officinale and Platango ovata (Cr) and Amaranthus spinosus (Ni) respectively. While the multi-metals accumulator plant species are Bidens pilosa (Cu, Pb and Ni), Chenopodium ambrosioides (Cd, Cu and Ni), Amaranthus spinosus (Cd, Cu and Cr), Ajuga bracteosa (Pb and Ni) and Rumex hastatus (Cd and Ni). However, the single heavy metal accumulator plant species are Sonchus espera (Pb), Conyzea Canadensis (Ni), Platango ovata and Malvastrum coromandelianum (Cu) respectively. These plants could find valuable applications in practical phytoremediation for the remediation near mining tailings at Abbottabad. Moreover, the use of local plants is a promising approach not only for in situ accumulation and stabilization of heavy metals but also for tolerance and environmental adaptations in the contaminated area.