Metal Concentrations In Plants Research Articles

Impairment of the Zn/Cd detoxification systems affects the ability of Salmonella to colonize Arabidopsis thaliana

Salmonella capacity to colonize different environments depends on its ability to respond efficiently to fluctuations in micronutrient availability. Among micronutrients, Zn, besides playing an essential role in bacterial physiology, is a key element whose concentration can influence bacterial survival in a particular niche. Plant colonization by Salmonella enterica was described for several years, and some molecular determinants involved in this host-pathogen interaction have started to be characterized. However, it is still unclear if Zn plays a role in the outcome of this interaction, as well established for animal hosts that employ nutritional immunity strategies to counteract pathogens infections. In this study, we have investigated the involvement of Salmonella Typhimurium main effectors of zinc homeostasis in plant colonization, using Arabidopsis thaliana as a model host. The results show that to colonize plant tissues, Salmonella takes advantage of its ability to export excess metal through the efflux pumps ZntA and ZitB. In fact, the deletion of these Zn/Cd detoxification systems can affect bacterial persistence in the shoots, depending on metal availability in the plant tissues. The importance of Salmonella ability to export excess metal was enhanced in the colonization of plants grown in high Zn conditions. On the contrary, the bacterial disadvantage related to Zn detoxification impairment can be abrogated if the plant cannot efficiently translocate Zn to the shoots. Overall, our work highlights the role of Zn in Salmonella-plant interaction and suggests that modulation of plant metal content through biofortification may be an efficient strategy to control pathogen colonization.

Assessment of Heavy Metal Concentration in Soil and Plant and Evaluation of Bioconcentration Factor at Loumbila Market Gardening Perimeters, Burkina Faso

Agricultural soil quality deterioration resulting from an increase in the level of heavy metals is becoming more and more pronounced, thus raising the question on the safety status of human health and the environment. Determination of heavy metal concentration in soils and plants from Loumbila market gardening (Burkina Faso), and calculation of bioconcentration factor were undertaken. The heavy metals such as copper (Cu), nickel (Ni), lead (Pb), chromium (Cr), cadmium (Cd) and zinc (Zn) were measured using an atomic absorption spectrometer, model PERKIN ELMER AANALYST 200.
 In the soil where the pepper was grown, the concentration of chromium was 175 mg/kg, which is higher than the concentration limit which is 150 mg/kg. Also the concentrations of lead in the soils of onion (118 mg/kg), green bean (118 mg/kg), carrot (178 mg/kg) and pepper (135 mg/kg) were above the limit which is 100 mg/kg. The concentrations of chromium in Onion leaves (3.72 mg/kg), onions (4.65 mg/kg), lettuce (4.89 mg/kg), green beans (5.89 mg/kg) and bell peppers (3.56 mg/kg) were concentrations above the limit established by the FAO/WHO, which is 2.3 mg/Kg. The concentrations of lead in carrot, onion leaf, onion, lettuce, green bean and bell pepper were above the limit proposed by FAO/WHO.
 The bioconcentration factors show that the onion leaf (0.731), onion (0.929), lettuce (0.876), green bean (0.987) and bell pepper (0.858) are the plants that accumulate zinc and the carrot (0.524) accumulates nickel. The bioaccumulation of the metals in the vegetable from Loumbila market gardening decreased in the order of onion > lettuce > green bean > bell pepper > onion leaves > carrot.

Transcriptome Analysis Reveals the Stress Tolerance to and Accumulation Mechanisms of Cadmium in Paspalum vaginatum Swartz.

Cadmium (Cd) is a non-essential heavy metal and high concentrations in plants causes toxicity of their edible parts and acts as a carcinogen to humans and animals. Paspalum vaginatum is widely cultivating as turfgrass due to its higher abiotic stress tolerance ability. However, there is no clear evidence to elucidate the mechanism for heavy metal tolerance, including Cd. In this study, an RNA sequencing technique was employed to investigate the key genes associated with Cd stress tolerance and accumulation in P. vaginatum. The results revealed that antioxidant enzyme activities catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and glutathione S-transferase GST) were significantly higher at 24 h than in other treatments. A total of 6820 (4457/2363, up-/down-regulated), 14,038 (9894/4144, up-/down-regulated) and 17,327 (7956/9371, up-/down-regulated) differentially expressed genes (DEGs) between the Cd1 vs. Cd0, Cd4 vs. Cd0, and Cd24 vs. Cd0, respectively, were identified. The GO analysis and the KEGG pathway enrichment analysis showed that DEGs participated in many significant pathways in response to Cd stress. The response to abiotic stimulus, the metal transport mechanism, glutathione metabolism, and the consistency of transcription factor activity were among the most enriched pathways. The validation of gene expression by qRT-PCR results showed that heavy metal transporters and signaling response genes were significantly enriched with increasing sampling intervals, presenting consistency to the transcriptome data. Furthermore, over-expression of PvSnRK2.7 can positively regulate Cd-tolerance in Arabidopsis. In conclusion, our results provided a novel molecular mechanism of the Cd stress tolerance of P. vaginatum and will lay the foundation for target breeding of Cd tolerance in turfgrass.

Potential of Catharanthus roseus applied to remediation of disparate industrial soils owing to accumulation and translocation of metals into plant parts

Soil pollution is one of the major environmental concerns. Since the inception of the industrial revolution, numerous perilous compounds are being introduced into the environment by various means. Of these, heavy metals are considered the important soil contaminants that present significant peril to human health. While the preventive measures of environmental pollution lie in the awareness of mankind, eliminating the interfering consequences of pollutants that have already been released into the environment is the current challenge. The present work, therefore, aimed to determine the phytoremediation potential of Catharanthus roseus based on contamination indices. The metal concentrations in soil and plant were assessed using Atomic Absorption Spectrophotometry and Inductively Coupled Plasma -Mass Spectrophotometry. The results showed that C. roseus acted as a good tool in remediating industrially contaminated soils. Plants grown under metal stress showed enhanced antioxidant potential. Further, the plant exhibited increased chlorophyll, pectin and lignin content in response to heavy metals, suggesting significant relation between plant metabolism and mental stress. Phytoremediation using plants like C. roseus therefore, can be esthetically pleasing and more publicly acceptable than the disruptive physical and chemical processes currently in use.

Concentration and mobility of trace elements (Li, Ba, Sr, Ag, Hg, B) and macronutrients (Ca, Mg, K) in soil-orchid system on different bedrock types.

The mobility of chemical elements in the soil-orchid system has been poorly studied. The aim of this study is to evaluate the uptake and mobility of several trace (Li, Ba, Sr, Ag, Hg, and B) and macronutrients (Ca, Mg, and K) in the orchid Anacamptis morio (L.) R.M.Bateman, Pridgeon & M.W.Chase from soils in western Serbia. The sampling sites are characterized by three different bedrock types-cherts, limestones, and serpentines, which are the source of the significant chemical differences in the elemental status of the soil and plant tissues. The four-step Community Bureau of Reference sequential extraction procedure was used to determine the distribution of fractions and predict their potential phytoavailability. The orchid and soil samples were analyzed for total elemental content analysis using ICP-OES. The greatest potential for plant availability was determined for Ba and Sr, representing about 80% of the total soil content. More than 40% of Li in the soils was found to be potentially phytoavailable. Significant correlations were found between the total content of Li, B, and Sr in soils. Between 38 and 60% of Li content and more than 80% of Ba and Sr content were determined to be potentially phytoavailable by sequential analysis. The highest bioconcentration factor (> 1) was determined in the case of B and Sr for all orchid organs, while translocation factor for Li was highest in tubers and leaves. The studied elements were mainly stored in tubers and roots, indicating the exclusion strategy of A. morio as a metal tolerance mechanism. The data obtained showed significant differences in metal content in soils and plants originating from sites with different parent materials, suggesting that bedrock type and associated soil properties are important factors that determine chemical element mobility and uptake.

Influence of Copper Amendments on Soil Properties, Growth and Metal Accumulation by Mentha arvensis L.

A polyhouse study was conducted to assess the influence of copper amendments on the soil properties, plant growth parameters (fresh weight and plant height) and metal accumulation in Mentha arvensis L. The amendments of copper were 270, 500, 700 and 900 mg kg-1 in triplicate along with an unamended control. After 90 days of plant growth, the aerial parts of the plant were harvested and the physicochemical properties of the soil such as pH, EC, %OC, %OM and metal content in plant and soil were recorded. The pH and EC values were higher for the amendments as compared to the control. The pH (8.22) and EC (0.80 dS m-1) values were the highest for Cu270 mg kg-1 and Cu500 mg kg-1 amendments, respectively. The percentage of OC and OM was the highest (1.16%, 2.00%) for Cu500 mg kg-1. The plant height was maximum (36.30 cm) for the control plant while the fresh weight was maximum for Cu700 mg kg-1 amendment. The copper accumulation was observed to be the highest (19.3 mg kg-1) for the Cu500 mg kg-1 amendment and least (13.7 mg kg-1) for the higher amendment (Cu900 mg kg-1) showing that for all the amendments along with control, copper accumulation was within the permissible limit. Thus, growing medicinal and aromatic plants in the metal-rich soils can be a sustainable and environment-friendly approach to obtaining metal-free commercially important end products.

Взаимосвязи подвижности тяжелых металлов в почвах со свойствами почв

The paper shows the dependence of the content of mobile forms of heavy metals in soils on the properties of soils (pH, E, humus, content of mobile phosphates). It is shown that an increase in the content of mobile forms of heavy metals in soils leads to a decrease in the intensity of photosynthesis and transpiration in plants, to an increase in the content of heavy metals in plants, to a significant change in the microbiological activity of soils and, in particular, to a decrease in nitrification in soils. The expediency of describing the dependence of the content and mobility of heavy metals in soils using correlation equations and regression equations is shown. Keywords: HEAVY METALS, SOIL, PLANTS, MICROFLORA, POLLUTION, INTERRELATIONS

Використання біоіндикаційного методу для оцінки забруднення атмосферного повітря важкими металами

The results of studies of chemical pollution (Pb, Zn) of perennial grasses—Elymus repens L., Artemisia absinthium L., and Hypericum perforatum L.—on background plots and within the areas of impact of industrial enterprises in Kropyvnytskyi (Ukraine) are presented. It is noted that chemical pollution is the most dangerous. The activity of enterprises is considered, in the result of which heavy metals enter the air. Testing of plants (stems and leaves) was carried out at a distance of 10–100 m from the enterprises. The content of heavy metals in the aboveground part of plants was analysed by atomic absorption spectrophotometer in the laboratory of the Department of Exploratory and Ecological Geochemistry, IGMR NAS of Ukraine. The comparison of sorption properties of different plants in the same phases of development allowed plants with bioindication capabilities to be identified. The results of the analysis showed that plants most effectively accumulate the maximum amount of heavy metals from the atmospheric air at the end of the summer dormancy phase (second half of August). At this time the plant requires the minimum amount of nutrients that it takes from the soil. Stems and leaves of perennial grasses actively accumulate aerosols and fine dust on their surface due to plant secretions with the formation of a mucous film that actively adsorbs heavy metal ions. The background, minimum, and maximum content of heavy metals in plants is determined. Comparing the content of heavy metals in plant samples in the background and study plots, it was found that E. repens near industrial enterprises is the most effective bioindicator of air pollution. In order to determine the level of atmospheric air pollution using bioindication methods, the index of plant contamination (Sр) was proposed, which is the ratio of concentration coefficient of heavy metals and their amount. An assessment scale for atmospheric air pollution with heavy metals has been developed based on the contamination index (Sр) of bioindicator plants: the degree of pollution is 1–3—weak, 3–6—medium, 6–9—strong, more than 9—very strong. The proposed coefficients allow for conducting a situational assessment of atmospheric air pollution with heavy metals using bioindication methods.

ASSESSING HEAVY METAL CONTAMINATION IMPACT IN MAIZE GROWING ALONG THE ROADSIDE

Now a days heavy metal contamination along the roadside is a matter of concern especially in industrial areas of developing countries. The non-degradable nature of heavy metals makes them injurious to all living beings. Soil, dust, and plants are the main media for the entry of these metals into our food chain. Thereby, a survey was conducted to assess the nickel (Ni), copper (Cu) and manganese (Mn) levels in roadside dust, soil and maize crop growing along the roadside. Moreover, the effects of these metals were also assessed on the growth and physiology of maize. Plant, soil, and dust sample were collected from Millat road Faisalabad. Samples were collected from four sites at three different distances (10m, 30m, 60m) from the road. Each site had a distance of 5 km from the other site. As result, metal concentration in soil, dust and maize decreased with increasing distance from the road. Maximum metal concentration in dust, soil and plant was noted at the distance of 10m (Cu 40.1, Mn 189.66 and Ni 5.6 mg kg-1 in soil; Cu 11.3, Mn 179.7 and Ni 9.37 mg kg-1 in dust; Cu 11.8, Mn 23.01 and Ni 3.75 mg kg-1 in plant) from the roadside. Likewise, maize plants near the roadside showed more metal concentration with retarded growth and physiology.

Insights to proteomics and metabolomics metal chelation in food crops.

Metal pollution of water and soil ecosystems has been linked to stress and/or toxicity in plants, thus affecting the quality and productivity of food crops. This condition has further aggravated the essential food demand caused by the increase in the human population. Reports from previous studies have shown that correcting the noxiousness due to metal stress tolerance, requires several modes of action in the systemic, tissue, cellular, physiological, biochemical, and molecular levels in food crops which might be apparent in terms of enhanced productivity. The possible targets of the toxicity impact of metals in food crops are the MG (methylglyoxal) and ROS (reactive oxygen species) which could result in damage to the DNA structure, enzymes inactivation, protein oxidation, and lipids’ peroxidation. This current review evaluates insights into proteomics and metabolomics of metal chelation in food crops with special effects on the toxicity, tolerance, and partitioning of metals towards better health. Detailed information on the biochemical and physiological mechanisms of plant stress from metal induction and tolerance was highlighted. The specific information of various tolerance strategies of food crops under trace element toxicity, the function of metabolites, proteins, and food crop hormones in stress tolerance to heavy presences of metal contents in plants is discussed. Information on the partitioning of trace elements in food crops was enlisted. The health benefits and possible risks from the consumption of trace metals in food crops were evaluated followed by recommending the future research directions.

Estimation of heavy metal concentrations (Cd and Pb) in plant leaves using optimal spectral indicators and artificial neural networks.

The necessity of continuously monitoring the agricultural products in terms of their health has enforced the development of rapid, low-cost, and non-destructive monitoring solutions. Heavy metal contamination of the plants is known as a source of health threats that are made by their proximities with pollutant soil, water, and air. In this paper, a method was proposed to measure lead (Pb) and cadmium (Cd) contamination of plant leaves through field spectrometry as a low-cost solution for continuous monitoring. The study area was Mahneshan county of Zanjan province in Iran with rich heavy metal mines that have more potential for plant contamination. At first, we collected different plant samples throughout the study area and measured the Pb and Cd concentrations using ICP-AES, in which we observed that the concentrations of Pb and Cd are in the range of 1.4 ~ 282.6 and 0.3 ~ 66.7 μgg-1, respectively, and then we tried to find the optimum estimator model through a multi-objective version of genetic algorithm (GA) optimization that finds simultaneously the structure of an artificial neural network and its input features. The features extracted from the raw spectrums have been collimated to be compatible with the Sentinel-2 multispectral bands for the possibility of further developments. The results demonstrate the efficiency of the optimum estimator model in estimation of the leaves' Pb and Cd contamination, irrespective of the plant type, which has reached the R2 of 0.99 and 0.85 for Pb and Cd, respectively. Additionally, the results suggested that the 783-, 842-, and 865-nm spectral bands, which are similar to the 7, 8, and 8a sentinel-2 spectral bands, are more efficient for this purpose.

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.

Raman Spectroscopy Enables Non-invasive and Confirmatory Diagnostics of Aluminum and Iron Toxicities in Rice.

Metal toxicities can be detrimental to a plant health, as well as to the health of animals and humans that consume such plants. Metal content of plants can be analyzed using colorimetric, atomic absorption- or mass spectroscopy-based methods. However, these techniques are destructive, costly and laborious. In the current study, we investigate the potential of Raman spectroscopy (RS), a modern spectroscopic technique, for detection and identification of metal toxicities in rice. We modeled medium and high levels of iron and aluminum toxicities in hydroponically grown plants. Spectroscopic analyses of their leaves showed that both iron and aluminum toxicities can be detected and identified with ∼100% accuracy as early as day 2 after the stress initiation. We also showed that diagnostics accuracy was very high not only on early, but also on middle (day 4–day 8) and late (day 10–day 14) stages of the stress development. Importantly this approach only requires an acquisition time of 1 s; it is non-invasive and non-destructive to plants. Our findings suggest that if implemented in farming, RS can enable pre-symptomatic detection and identification of metallic toxins that would lead to faster recovery of crops and prevent further damage.

Spatiotemporal Differences and Ecological Risk Assessment of Heavy Metal Pollution of Roadside Plant Leaves in Baoji City, China

The concentration of heavy metals in plants’ leaves can effectively indicate the spatiotemporal differences of environmental pollution, providing a scientific basis for the monitoring of urban air quality. The concentration of Ni, Cu, Cd, Pb and Zn in the leaves of five different species (Ophiopogon japonicus, Ligustrum vicaryi, Platanus acerifolia, Sophora japonicaand Cedrusdeodara) were measured, which were from I, II, III, IV (0.05 m, 0.25 m, 1 m, 4 m) at different times (May and November) in the green belt of Baoji city. The degree of heavy metal pollution and potential ec ological risk were analyzed. The results revealed that the concentration of Zn, Cu and Pb in roadside plant leaves was relatively high. In May, the heavy metal concentration was the highest in the leaves of C.deodara, whereas this was the case for S. japonica in November. Arbors were more effective at capturing particles from the atmosphere than low plants. At the same height, areas with high levels of heavy metal pollution in May were basically the same as that in November, and areas with high levels of pollution were affected by traffic and industry. The pollution index and the comprehensive index of potential ecological risk of element Cd were the highest, indicating that the potential harm of Cd to the environment should receive more attention from the Government.

Calorific Value of Festuca rubra Biomass in the Phytostabilization of Soil Contaminated with Nickel, Cobalt and Cadmium Which Disrupt the Microbiological and Biochemical Properties of Soil

The choice of optimal plant species for phytoremediation and organic fertilization plays an important role in stabilizing the functions of soils contaminated with heavy metals. The influence of nickel, cobalt and cadmium on the biomass yield and calorific value of Festuca rubra, heavy metal concentrations in soil and plants and the microbiological, biochemical and physicochemical proprieties of soil were analyzed in a pot experiment. The tolerance index (TI) describing Festuca rubra’s ability to tolerate heavy metals, as well as the translocation (TF), accumulation (AF) and bioaccumulation (BF) factors of heavy metals in Festuca rubra were calculated. The experiment was conducted in two series: In soil fertilized and not fertilized with compost. Nickel and cobalt significantly inhibited the growth and development of Festuca rubra. The experiment demonstrated that this plant species can be grown on soil contaminated with heavy metals. Festuca rubra contained on average 46.05% C, 34.59% O, 5.91% H, 3.49% N, 0.19% S and 9.76% ash. Festuca rubra has a stable calorific value which is not affected by heavy metals; therefore, biomass harvested from heavy metal-polluted soil can be used for energy generation. The calorific value of Festuca rubra ranged from 15.924 to 16.790 MJ kg−1 plant d.m., and the heat of combustion from 17.696 to 18.576 MJ kg−1. It has a stable calorific value which is not affected by heavy metals, therefore biomass harvested from heavy metal-polluted soil can be used for energy generation. Festuca rubra is particularly useful for the phytostabilization of soil contaminated with cadmium and cobalt. Compost minimizes the adverse effects of heavy metal pollution on the microbiological, biochemical and physicochemical properties of soil.

Heavy Metals Contaminants in Watercress (Nasturtium officinale R. BR.): Toxicity and Risk Assessment for Humans along the Swat River Basin, Khyber Pakhtunkhwa, Pakistan

This research aimed to investigate the bioaccumulation and health risk associated with absorption of the selected heavy metals (HMs) i.e., lead (Pb), cadmium (Cd), zinc (Zn), and copper (Cu) in a wild leafy vegetable Nasturtium officinale that grows along the Swat River in swampy areas. The areas were categorized using the ecological risk index (RI), which indicates how heavy metal concentrations in soil and plants change over time. The bioaccumulation factor was greater than that at the 400 ≤ RI sites, indicating a probable health risk of these metals from N. officinale consumption. Furthermore, the health risk index for Cd and Pb was more significant, i.e., greater than one in the majority of the samples, indicating health concerns associated with consuming N. officinale from the study site. However, Zn and Cu levels were lower than the nutritionally needed levels, raising the risk of deficiency in the population. Plants cultivated in Pb and Cd-polluted sites were nutrient deficient in Cu and Zn. Intake of such plants can expose people to HM contamination and nutritional deficiencies. The results concluded that the plants accumulated significant HM contents and may have health concerns but are safe for consumption in children and adults.

Ability of Urtica dioica L. to adsorb heavy metals (Pb, Cd, As, and Ni) from contaminated soils

ABSTRACT Landfill leachate contains heavy metals that contaminate water and soil near the landfill site. Phytoremediation is a process of decontaminating soil or water by using native plants to adsorb and accumulate or break down pollutants. This study aimed to evaluate absorption and accumulation of heavy metals from simulated landfill soil by nettle. Nettle seeds were collected from the Tonekabon landfill site and planted in 243 pots. After reaching the 6-leaf stage, the plants were exposed to three concentrations of four heavy metals (Pb, Cd, As, and Ni) during the growing season. An atomic absorption spectrometer was used to measure the concentrations of the heavy metals in nettle plants and the morphological features of nettle fibers. The results showed that increases in the concentrations of the heavy metals in the soils led to their higher concentrations in all organs of the nettle plants (Pb> Ni> Cd> Ar), and larger quantities of the heavy metals were accumulated in the aerial parts of the plants. In parallel with this result, the dry weights of stem, leaf and root, and leaf area index also decreased. Values of TF> 1 and BAC <1 in plant organs showed the ability of nettle to accumulate more heavy metals when they were present at higher concentrations in the soil. Bioremediation using native plants for removal of heavy metals from soil and their accumulation in these plants is a low-cost and environmentally friendly technology. Nettle is a plant that grows wild in the landfills in northern Iran and, due to its ability to accumulative heavy metals in its organs, is a suitable plant species for their removal from soil.

Rice plant tolerance response to the exposure of heavy metals and its Impact on Plant Overall Morphological and Histological Features

Heavy metals bioaccumulation in the food supply chain is a critical environmental issue, required drastic action plans for health risk reduction. In this study, we aim to determine the effects of heavy metal exposure on the morphology and anatomy of paddy plant (Oryza sativa L.). Paddy plants were treated with single metal of Cd, Zn and Fe, while the combined metals were Cd+Zn, Cd+Fe and Zn+Fe, each at 5 different concentrations on 21st day of the germination. The results showed that all single and combined heavy metals upon solo and multiple exposures have a significant effect to the plant growth, where heavy metals influence root length, stem length, tree height, number of leaves, number of tillers, number of root hairs and total rice yield. The heavy metal content in paddy plants were in the order of root&gt;stem&gt;grain&gt;leaf. CO2 influences the growth of rice plants, but the effect of heavy metal exposure has influenced the rate of growth. A positive correlation was obtained between single exposure and double exposure in soil and paddy plant. The accumulation of single and combined heavy metals in greenhouses and CO2 greenhouses alters the cell structure and tissues of rice plants. Our findings also suggested that paddy plant has the ability to regulate its internal structure and adapt to high accumulation of heavy metals in plant structure, seemed to have some degree of tolerance to heavy metals.

Measurement of heavy metals in soil, plants and water samples based on MWCNTs modified with Bis(triethoxysilylpropyl)tetrasulfide by flame atomic absorption spectrophotometry

Heavy metals (HMs) are considered as the major environmental pollutants that accumulated in soil and plant. Consumption of such contaminated plants by humans and animals would ultimately harm the health of communities. This study aims to evaluate the amount of copper(Co), cadmium(Cd), and lead(Pb) in soil and cultivated plants that are irrigated by the city of Zabol’s wastewater. Also, the heavy metals determined in 20 mL of Zabol’s water based on Bis(triethoxysilylpropyl)tetrasulfide (S4[C3H6Si(OEt)3]2, TEOSiP-TS) modified on MWCNTs as an adsorbent by the uniform dispersive -micro-solid phase extraction (UD-µ-SPE) at optimized pH. In this study, 52 samples including wheat, corn grain, and wild spinach, as well as agricultural soil were selected randomly from three village stations. The concentrations of heavy metals in plants, soils, and water samples were measured using a flame atomic absorption spectrometer (F-AAS). By optimizing parameters, the linear range (LR) and the detection limit (LOD) of Cu, Cd, and Pb were obtained 1.5-1000 μg L-1, 1-200 μg L-1, 5-1500 μg L-1 and 0.5 μg L-1, 0.25 μg L-1, 1.5 μg L-1, respectively in water samples (RSD%&lt;2). This study indicates that irrigation of agricultural fields using wastewater causes the accumulation of heavy metals in soil and plants.

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.