Concentrations Of Elements In Plants Research Articles

Background Concentrations of Chemical Elements in Plants Inhabiting the Northern Part of Western Siberia and Changes They Undergo under the Impact of Oil and Gas Production

Background Concentrations of Chemical Elements in Plants Inhabiting the Northern Part of Western Siberia and Changes They Undergo under the Impact of Oil and Gas Production

A Multi-Target Regression Method to Predict Element Concentrations in Tomato Leaves Using Hyperspectral Imaging.

Recent years have seen the development of novel, rapid, and inexpensive techniques for collecting plant data to monitor the nutritional status of crops. These techniques include hyperspectral imaging, which has been widely used in combination with machine learning models to predict element concentrations in plants. When there are multiple elements, the machine learning models are trained with spectral features to predict individual element concentrations; this type of single-target prediction is known as single-target regression. Although this method can achieve reliable accuracy for some elements, there are others that remain less accurate. We aimed to improve the accuracy of element concentration predictions by using a multi-target regression method that sequentially augmented the original input features (hyperspectral imaging) by chaining the predicted element concentration values. To evaluate the multi-target method, the concentrations of 17 elements in tomato leaves were predicted and compared with the single-target regression results. We trained 5 machine learning models with hyperspectral data and predicted element concentration values and found a significant improvement in the prediction accuracy for 10 elements (Mg, P, S, Mn, Fe, Co, Cu, Sr, Mo, and Cd). Furthermore, our multi-target regression method outperformed single-target predictions by increasing the coefficient of determination (R2) for elements such as Mn, Cu, Co, Fe, and Mg by 12.5%, 10.3%, 11%, 10%, and 8.4%, respectively. Hence, our multi-target method can improve the accuracy of predicting 10-element concentrations compared to single-target regression.

Effect of some Environmental Factors on the Distribution and Spread of Artemisia scoparia Waldst. et Kit. in Basrah Governorate

This study was conducted during the period from October 2021 to November 2022, and four stations were selected: Hammar Musharraf, Al-Tuba, Artawi and Safwan, which are located in the southern desert of Basra Governorate, during which the distribution of the Artemisia scoparia plant was determined and the physical and chemical properties affecting it were studied. Heavy elements were also measured for the summer seasons. And winter for the two stations of Safwan and Hammar Musharraf. The highest air temperature was recorded at 49 C in July in Safwan station, and the lowest was 10 C in January for most of the study stations. As for the soil temperature, the highest was 46.2 C in the month of August in Al-Tuba station, and the lowest was 12 C in January in Safwan. As for air and soil humidity, the highest percentage was 62% and 10.2% in January at Hammar Musharraf station, and the lowest was 0.1% in June and September at Safwan and Artawi stations, respectively. The highest value of pH was recorded for the soil of the studied stations, which was 8.58 in Al-Tuba station in July, and the lowest was 6.01 in December in Hammar Musharraf. The highest soil salinity was 8.81 mg/L in Safwan in July, and the lowest was 0.01 mg/L in Hammar Musharraf and Al-Tuba in November and December, respectively. As for the organic matter, it was the highest of 0.13 gm in Hammar Musharraf in January, and the lowest was 0.01 gm in Artawi and Al-Tuba for most months of the year. As for the heavy elements, the highest presence in the soil of the aluminum element was recorded in Safwan, which amounted to 264.105 ppm in the summer, followed by the iron element of the same station in the summer as well, as its concentration reached 228.761 ppm, while the lowest concentration was in a donkey honorable in the winter of arsenic. It reached 0.005 ppm, and the highest concentration was in the summer of Safwan station, with a concentration of 57.4463 ppm, while the lowest concentration was in winter, with a concentration of 33.9196 ppm in Safwan. As for the concentrations of heavy elements in plants, the highest and lowest concentrations of zinc were recorded in Safwan in the summer and winter seasons, which amounted to 14.7 and 0.002 ppm, respectively. Winter season, with a concentration of 1.3902.

Dynamics of the Content and Distribution of Trace Elements in Sod-Podzolic Soils and Plants of Agrocenoses

The paper presents the results of a survey of sod-podzolic soils for agricultural purposes and plants of reference sites of the Ivanovo region for the content of boron, copper, cobalt, manganese and zinc in them, conducted in 2014 and 2021. Correlation analysis determined the influence of individual physical and chemical properties of soils on the content and distribution of available forms of trace elements in the soil and the relationship between the trace elements themselves. Changes in the availability of trace elements of the soils of the plots have been established. According to the amount of content of available forms of trace elements in soils, the need for the use of micronutrients is determined. The sequences of crops were determined by the content of trace elements in grain and straw of cereals, the green mass of forage grasses, as well as the distribution of trace elements between parts of the grown crop. Grain, straw and green mass were evaluated for compliance with veterinary standards for the content of copper, zinc and cobalt in feed. The coefficients of accumulation of trace elements by plant products of crops are calculated and their comparative analysis is carried out. By the magnitude and sign of the correlation coefficients between the concentrations of trace elements in plants, the manifestation of antagonism and synergy between trace elements was determined. The Pearson and Spearman correlation coefficients between the content of mobile forms of trace elements in the soil and their content in plant products, as well as between the content of trace elements in grain and straw of cereals revealed their strength and the ambiguous nature of the relationships..

Accumulation of chemical elements in the roots of <I>Euphorbia fischeriana</I> Steudel in the Shilka river basin (Transbaikal region)

Background. Euphorbia fischeriana Steudel is used in traditional and herbal medicine in Russia and China. Its roots contain 241 chemical components, but there is not enough knowledge about the plant’s elemental composition. Concentrations of chemical elements in plants have an impact the effectiveness of medical products.Materials and methods. The research was conducted in the Transbaikal region. Plants were analyzed using an ICP-MS Elan 9000 mass spectrometer (Canada). The ICP-MS method of measuring metal content in solid objects, PND F 16.1:2.3:3.11-98 was used. Chemical analysis of the soil was performed at Kostromskaya State Station of Agrochemical Service. The obtained data were statistically processed using the Microsoft Excel software.Results. The accumulation of macro- and microelements in plant roots was studied (Ca, P, Mg, Na, Fe, Mn, Zn, Mo, Cr, Co, Se, Cu, B, Ni, V, As, Li, Pb, Ba, Bi, Cd, Hg, Be, Sb, Rb, Zr, Sn, Ag, W, Sr, and Ti). The chemical elements whose concentrations were significantly higher or, contrariwise, lower than the clarke of terrestrial plants were identified. Accumulations of Ti, Ag, As, Cr, Sr, Li, Ba, Mo, Fe, Bi, and Sb in descending order were 2–14 times higher than the clarke of terrestrial plants. Concentrations of Mn, Cd, Se, and especially V and Cu in E. fischeriana roots were low (0.01–5% of the clarke). The concentration of As in the test areas exceeded the threshold limit value for medicinal herbage and medicinal plant products (OFS.1.5.3.0009.15). Conclusion. The study made it possible to find deficiencies of a number of vital elements in E. fischeriana roots, discrepancy between the tested herbage and the threshold limit value for As, and increased accumulation of a number of toxic and potentially toxic elements compared with the clarke.

Short-term Variability of Macro- and Trace Elements in Elymus Repens L. and Urtica Dioica L.

The main aim of the research was to study short-term changes in the concentrations of elements in two widely distributed plant species, couch grass and nettle and in the rhizosphere soil of the plants. The sampling of plants and soil was carried out on three dates: 3, 10, and 25 May 2021. On each day of sampling, the plants and soil were collected three times: at 9:00, 14:00, and 19:00. The ICP-OES and ICP-MS analytical techniques were used for determination of elements in the plant and soil samples. The Raman spectroscopy was applied to study variations in the organic compounds. The concentrations of both macro-nutrients and trace elements in plants varied greatly over daytime on all dates of sampling. The differences between concentrations of many elements in the plants collected at different times during a day were statistically significant. There were also statistically significant differences between concentrations of some elements (Na, Mg, P, K, Fe, Ba) in the plants collected on different dates. The relative intensity of diffuse luminescence of the rhizosphere soil of couch grass and nettle was different during daytime and also differed between the soils taken from roots of the two plant species, especially in the beginning of May. The experimental data indicates that the daily variations of the element concentrations in plants might be a result of multiple effects of various factors. The differences in the daily element variations in the couch grass and nettle growing in the same site and collected simultaneously might be due to the fact that these plants belong to different clades. The diurnal fluctuations (that also include regular changes in the element concentrations in plants) can be different for monocotyledons (couch grass) and dicotyledons (nettle). New experimental findings on short-term variations in the concentrations of macro-nutrients and trace elements can help to gain a new insight into accumulation of the elements in different plant species and also be useful in agricultural practice.

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

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

Landscape geochemical conditions and patterns of inter-element redistribution of heavy metals in landscapes of Kivertsi National Nature Park “Tsumanska Pushcha”


 
 
 nalysis of landscape geochemical conditions of the territory of Kivertsi National Nature Park “Tsumanska Pushcha” was carried out also the levels of pollution of landscapes within the park and adjacent territories were established. Features of the accumulation and distribution of pollutants in the landscapes of the territory under conditions of natural and Technogenic geochemical anomalies are considered. The landscapes of the studied migration classes (calcium, calcium carbonate, carbonate clayey, acidic calcium) are characterized by a relatively high coefficient of migration intensity due to relatively weak buffering capacity, low water retention capacity and contrasting moisture regime. However, strong gleyed horizons are able to fix contaminants during their surface movement. Using the methods of landscape geochemical research, analytical methods, data on the gross and mobile content of heavy metals were obtained and analyzed. The highest concentrations of manganese and chromium are found in soils differentiated on loess sediments, nickel and copper on glacial sediments. Most of the studied heavy metals exceed the regional geochemical background. In terms of the gross content in soils, trace elements form the following geochemical series: Zn>Cu>Pb>Ni>Mn>Cr. The accumulation of lead up to 2-3 MPC in forest litters is clearly traced. Dependences of the stability of landscapes to Technogenic pollution on the level of conservation of natural geochemical parameters of soils, the degree of their anthropogenic transformation and the level of heavy metals incomings have been established. All studied plants maximally accumulated Mn, Cu, Cr and minimally Zn and Ti which is consistent with the patterns of migration of these elements in the soil. The high accumulation of heavy metals in the aboveground part of the studied plants indicates a significant removal of elements from the soil, which, in turn, makes it possible to consider certain plant species as potential phytoremediators. According to the average values of the concentration of macro elements in plants, the following geochemical series is established: CaO>K2O>MgO>P2O5>SiO2>SO3> Al2O3> Fe2O3>Na2O>TiO2. On the basis of the data obtained, 4 types of biogeochemical bonds between chemical elements in the soil – plant system for the territory of the NPP were identified: V, Ti - soil> plant; Ni - soil <plant; Cr - soil> plant; Mn, Cu - soil <plant.
 
 

Zinc-biofortified lettuce in aeroponic system

Zinc (Zn) deficiency can be mitigated by several procedures, including food biofortification. Agronomic biofortification is a process that aims to increase the concentration of mineral elements in plants through fertilization. Therefore, the objectives of this study were to evaluate the possibility of producing zinc-biofortified curly lettuce in an aeroponic system and to establish the appropriate zinc dose to be used. The experiment was conducted in a greenhouse under aeroponic system, with the Filó lettuce cultivar. The treatments consisted of four doses of Zn (25, 50, 75 and 100 μmol L−1 of Zn), plus the control (0 μmol L−1 of Zn). The source of Zn used was ZnSO4.7H2O. The experiment was set up in a completely randomized design with four repetitions. The nutrient solution was changed once a week and monitored daily by measuring the pH. Thirty-seven days after transplantation, the following variables were evaluated: fresh shoot mass, dry mass of leaves, stem and root system, Zn concentrations and accumulation in leaves, stem and root, shoot and root system ratio, total root length, specific root surface area and total root volume. No symptoms of Zn toxicity were seen the plants. The greatest accumulation of Zn occurred in the roots, followed by the leaves and stem. Lettuce shoot mass increased to 224.19 g with increasing Zn concentration in the solution to 47.2 μmol. Under the conditions of study, the curly lettuce cultivar can be considered biofortified with 50 μmol L−1 of Zn, without affecting the productive characteristics of the crop.

Time-Dependent Changes in the Physico-Chemical Parameters and Growth Responses of Sedum acre (L.) to Waste-Based Growing Substrates in Simulation Extensive Green Roof Experiment

Over the last decade, an increase in the use of locally available, recycled, and waste materials as growing media components have occurred in various regions of the world in extensive green roof technology. For eco-concept reasons, such a strategy appears to be appropriate, but can be problematic due to difficulties in obtaining proper parameters of growing substrate. The growing media should be properly engineered in order to enable the proper functioning of green roofs and provide suitable environment for ideal root growth. The aim of the study was to assess the utility of locally occurring waste materials for growing media composition and estimate plant- and time-dependent changes in the physico-chemical parameters of waste-based substrates in a simulated extensive green roof system during a two-year Sedum acre L. cultivation. Five different substrate compositions were prepared using silica waste, crushed brick, Ca- and Zn-aggregates, melaphyre, tuff, sand, muck soil, urban compost, spent mushroom, and coconut fibres. Optimal water capacity, particle-size distribution, pH and salts concentration were found in all substrates. A higher concentration of macronutrients (N, P, K, Mg) and trace elements (B, Cu, Fe, Mn, Zn, Cd, Ni, Pb, and Cr) was found in waste-based substrates than in the commercial medium. In comparison to the parameters determined before establish the experiment, bulk density of tested growing media decreased, except for the substrates where the source of organic matter was the rapidly mineralising spent mushroom. The organic matter content in substrates after the two-year vegetation increased in relation to the ready-made substrate, with the exception of the composition with spent mushroom. After two years of the experiment, all available macronutrients and trace elements (with the exception of mineral N, K, SO4-S, and B) concentration were higher than in 2014, while pH, salt concentration was lower. In general, plants grown in waste substrates had lower dry matter content and higher biomass. A significantly higher biomass of S. acre L. was found in the first year of the experiment. In the second year of the research, the plants grown in the commercial medium, the substrate with silica waste, and the substrate with spent mushroom produced higher biomass than in the first year. No symptoms of abnormal growth were observed, despite the higher trace element concentrations in plants collected from waste-based substrate. Waste-based growing media can be considered as a valuable root environment for S. acre L. in an extensive green roof system.

Plantago subulata as indicator of potentially toxic elements in the substrate.

Plantago subulata is a facultative serpentinophyte, with predominantly ultramafic distribution in Serbia and Montenegro. The plant samples were collected from ultramafic and non-ultramafic substrate, including two abandoned mining sites, with the aim to assess the accumulation potential of this species. The samples were collected from 10 sites in Serbia and Montenegro and element concentrations in plants and soils were determined. Particularly high concentrations of Fe, Cu, Mn, Zn, and Cd were found in the soil and plant samples from an abandoned iron mining site, Mt. Kopaonik, Suvo Rudište. The concentrations of Ni, Cr, Fe, Co, and Cd were statistically different between soil and plant samples from ultramafic and non-ultramafic bedrock. Considering the fact that concentrations of Zn, Ni, and Cr in roots and shoots were positively correlated with their respective contents in the soil, i.e., the chemical composition of the plant and soil samples reflected the characteristics of the substrate, and for most of the elements analyzed, P. subulata acted as indicator species. For Cd and Pb, only the root concentrations were positively correlated with soil content, indicating exclusion and root sequestration as the main tolerance strategies for these elements. Although below the hyperaccumulation threshold, a strong accumulation capacity of P. subulata was found for Ni and Cu.

Processes at the soil–root interface determine the different responses of nutrient limitation and metal toxicity in forbs and grasses to nitrogen enrichment

Abstract Nutrient limitation and metal toxicity have been implicated in changes of grassland communities by nitrogen (N) deposition. Below‐ground processes, especially those at the soil–root interface, play important roles in determining variation in nutrient concentrations in plants. However, few studies have specifically focused on the roles of these processes in mineral‐element acquisition in grassland plants in response to N enrichment. Here we investigated the contributions of below‐ground processes at the soil–root interface to the differential acquisition of phosphorus (P), calcium (Ca) and manganese (Mn) by forbs and grasses of a temperate steppe in response to N addition by combining field and glasshouse experiments. Nitrogen addition increased the concentrations of both leaf P ([P]) and Mn ([Mn]) and decreased leaf [Ca] of forbs while it had little effects on leaf concentrations of these elements in grasses. Nitrogen addition led to a higher activity of acid phosphatase in the rhizosphere of forbs, and greater release of protons and carboxylates from forb roots than grass roots, contributing to the differential [P], [Ca] and [Mn] in the leaves of forbs and grasses. Applying oxalate to soil to simulate the release of carboxylates by N enrichment enhanced [P] and [Mn], and decreased [Ca] in the soil solution. However, addition of hydrogen‐ion increased [P], [Mn] and [Ca] in the soil solution. Lime addition mitigated the N‐addition‐induced soil acidification while it did not abolish the stimulatory effect of short‐term N addition on leaf [P] and [Mn] of forbs. Therefore, we conclude that differences in the eco‐physiological processes at the soil–root interface account for changes in leaf [P], [Ca] and [Mn] under short‐term N addition, and that soil acidification aggravates the responses of these elements, especially [Ca] and [Mn], to long‐term N enrichment. Synthesis. Our results highlight the contribution of below‐ground processes, especially those at the soil–root interface, to variation in plant element concentrations between dominant forbs and grasses in the temperate steppe. These findings greatly enhance our mechanistic understanding of the effects of N deposition on grassland communities.

Agronomic Biofortification of Stevia rebaudiana with Zinc Oxide (ZnO) Phytonanoparticles and Antioxidant Compounds

Agronomic biofortification is a process used to increase the concentration of essential elements in plants through fertilization and thus improve their nutritional quality. Increasing the content of Zn+2 in Stevia rebaudiana plants would imply adding value to the crop. The use of ZnO phytonanoparticles, in addition to increasing the content of Zn+2, can also generate an inductor effect that promotes the synthesis of metabolites of commercial interest. This study reports the effect of fertilization with ZnO phytonanoparticles on morphometric parameters of S. rebaudiana plants and the content of Zn+2, stevioside, rebaudioside A, total phenols, flavonoids and the antiradical activity of leaf extracts. Biofortification was carried out in a hydroponic culture using peat moss/agrolite as a support under a completely random experimental design. The green ZnO nanoparticles were added via root at different concentrations. The physiological and morphometric parameters of the plant were not affected with respect to the control by the use of phytonanoparticles. The biofortification of S. rebaudiana with ZnO phytonanoparticles at a concentration of 75 mg/L enhanced zinc content up to 406.8% with respect to the control. The total phenols (60.5%) and flavonoids (87.8%) were also increased without having a negative effect on plant growth. The biosynthetic pathway of steviol glycosides was not affected.

Cadmium and lead affect the status of mineral nutrients in alfalfa grown on a calcareous soil

ABSTRACT Cadmium (Cd) and lead (Pb) are toxic trace elements which are not essential for plants but can be easily taken up by roots and accumulated in various organs, and cause irreversible damages to plants. A pot experiment was carried out to investigate the individual and combined effects of Cd (0, 10, 20 mg kg−1) and Pb (0, 500, 1000 mg kg−1) level in a calcareous soil on the status of mineral nutrients, including K, P, Ca, Mg, S, Fe, Mn, Cu, and Zn, in alfalfa (Medicago sativa L.) plants. Soil Pb level considerably (P ≤ 0.05) affected the concentrations of more elements in plants than soil Cd level did, and there were combined effects of soil Cd level and Pb level on the concentrations of some nutrients (Ca, Mg, and Cu) in plants. The effects of soil Cd level and Pb level on plant nutrient concentrations varied among plant parts. Cd and Pb contamination did not considerably affect the exudation of carboxylates in the rhizosphere. An increase in rhizosphere pH and exudation of significant amounts of carboxylates (especially oxalate) in the rhizosphere might contribute to the exclusion and detoxification of Cd and Pb. Neither shoot dry mass nor root dry mass was significantly influenced by soil Cd level, but both of them were considerably reduced (by up to 25% and 45% on average for shoot dry mass and root dry mass, respectively) by increasing soil Pb level. The interaction between soil Cd level and Pb level was significant for root dry mass, but not significant for shoot dry mass. The results indicate that alfalfa is tolerant to Cd and Pb stress, and it is promising to grow alfalfa for phytostabilization of Cd and Pb on calcareous soils contaminated with Cd and Pb.

THE ELEMENTAL COMPOSITION OF THE VEGETATIVE ORGANS OF SORTS REGAL AIR AND SPEAK TO ME OF HEMEROCALLIS HYBRIDA

The data on the content of 22 chemical elements in the leaves and rhizomes of Hemerocallis hybrida plants of the Speak to me and Regal Air varieties growing in soil-ecological conditions of the forest-steppe zone of Western Siberia are presented. The General regularities of accumulation and distribution of macro- and microelements in leaves and rhizomes of plants of two varieties of daylilies are established: excess of the content of many microelements (vanadium, chromium, nickel, rubidium) in rhizomes in comparison with leaves. It was revealed that the concentration of chemical elements in plants differed both in organs and between varieties. The peculiarity of the mineral composition of the Regal Air variety was the excess of the total content of trace elements in 1.5–3 times compared to the variety Speak to me. Concentrations of individual elements in the leaves and rhizomes of daylilies differed significantly. It is shown that in both varieties in the leaves the amount of bromine was 4 times higher than in rhizomes, strontium – 1.5–1.8 times. The concentration of toxicant elements in the phytomass of Hemerocallis hybrida varieties was significantly lower than permissible concentration, which makes it possible to use them for medicinal purposes.

Use of Glauconite in Potato Cultivation Technology

In intensive technologies of cultivation of potatoes, the need for trace elements is increasing. The concentration of trace elements in plants is very small, but the importance of these elements in biochemical processes is difficult to overestimate. The deficiency of trace elements is the root cause of many functional disorders. Trace elements in plants are part of enzymes, stimulate and accelerate plant development, increase resistance to adverse environmental conditions, etc. Also, with their shortage, crop productivity decreases. The use of natural minerals, such as glauconite, containing trace elements, allows improving comprehensive nutrition and increase productivity. Getting early production of high quality potatoes in the summer is important and relevant in the modern world. The use of glauconite in the conditions of the Moscow region, along with fertilizers and irrigation, allows obtaining high-quality products and increasing productivity by 6.3... 29.0%.

The Volcanism and the Geochemistry of the Soil and Vegetation in Kamchatka. Part 3. The Elemental Composition of Vegetation in Volcanic Ecosystems

The relationship between the chemical composition of plants and the active volcanism of Kamchatka is determined by the fact that the dominant chemical elements for the plants, volcanic ashes, and soils are invariably Ca, Mg, Mn, P, Cu, Zn, and Sr. We have found an increased geochemical background for Kamchatka plants relative to the bulk chemical composition of the soils in the peninsula. The concentrations of Br, Hg, Hf, Sb, Ga, W, and K relative to the clarkes in living matter were higher by factors of 3 to 5 in the plants of this region. While the concentrations of chemical elements in plants of different areas are subject to little variation, we found a relatively rich biogeochemical background in the Western Area of Southern Province (the western coast of Kamchatka); in this area the oldest (for Kamchatka) near-surface volcanic ashes have been transformed into accumulative humus horizons. It was found for the area where young volcanic ashes were deposited in the proximity of active volcanoes that the vegetation is relatively rich in chemical elements and the soils are depleted in mobile forms of elements. Farther from the volcanoes, however, in the zone where ashes of remote origin were deposited, one notes a comparative depletion in the plants and an enrichment in the soils in relation to accessible elements.

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

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

Enrichment of trace elements in colonies of the yellow-legged gull (Larus michahellis) in the Atlantic Islands National Park (Galicia-NW Spain)

Marine-derived nutrients are known accumulate in seabird breeding colonies due to the deposition of nutrient-rich biological materials, thus greatly altering the functioning and dynamics of these terrestrial ecosystems. Here we present the results of a sampling survey carried out during three years in yellow-legged gull colonies in the Atlantic Islands of Galicia National Park (NW Spain) with the aim of evaluating the influence of the colonies on the accumulation of trace elements, including micronutrients (Cu, Zn, Se, Co, Mo, Ni) and toxic elements (Cr, Cd, Hg, Pb, As, Ag), in the surrounding environments. For this purpose, we analysed samples of biological materials produced by the seabirds (pellets, excrement, feathers, eggs) and of soil, plants and inland water from several different subcolonies and control zones without seabirds.The concentrations of most of the elements were higher in excrement and pellets (mean values: Zn: 152, As: 50 mg kg−1, Cd: 6, Co: 5 mg kg−1) than in feathers and eggs. The flow of trace elements into the breeding colonies, considering only the excrement, revealed a very high level of trace element deposition for a supposedly pristine environment (Zn: 2667, Cd: 70, Cu: 315, As: 64 g ha−1). The total concentrations of trace elements in soil were consistent with the long-term impact of the seabirds. Thus, the values in areas which this impact was greatest were significantly higher than in the control zones, particularly considering the most labile geochemical fractions of the soil. The concentrations of some elements (i.e. Co, As, Cd) were also higher in the inland waters in the colonies than in control zones. Finally, the concentration of trace elements in plants varied depending on the species and element considered.

Effects of biochar addition on toxic element concentrations in plants: A meta-analysis

Consuming food contaminated by toxic elements (TEs) could pose a substantial risk to human health. Recently, biochar has been extensively studied as an effective soil ameliorant in situ because of its ability to suppress the phytoavailability of TEs. However, despite the research interest, the effects of biochar applications to soil on different TE concentrations in different plant parts remain unclear. Here, we synthesize 1813 individual observations data collected from 97 articles to evaluate the effects of biochar addition on TE concentrations in plant parts. We found that (1) the experiment type, biochar feedstock and pyrolysis temperature all significantly decreased the TE concentration in plant parts; (2) the responses of Cd and Pb concentrations in edible and indirectly edible plant parts were significantly more sensitive to the effect of biochar than the Zn, Ni, Mn, Cr, Co and Cu concentrations; and (3) the biochar dosage and surface area, significantly influenced certain TE concentrations in plant tissues as determined via correlation analysis. Moreover, the only exception in this study was found for metalloid element (i.e., As) concentrations in plants, which were not significantly influenced by biochar addition. Overall, the effects of biochar on TE concentrations in plant tissues were negative, at least on average, and the central trends suggest that biochar has a considerable ability to mitigate the transfer of TEs to food, thereby reducing the associated health risks. Our results provide an initial quantitative determination of the effects of biochar addition on multifarious TEs in different plant parts as well as an assessment of the ability of biochar to reduce TE concentrations in plants.