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Heavy Metals in Agricultural Soils
85-89Views:82The soil constitutes the basis of the food chain. To keep soil conditions in a good trim is very important, it’s part of the sustainable development and of producing food supply harmless to health.
In some cases, soil productivity is the only important part, qualitative requirements or economical characteristics can improve it. The soil is threatened by two danger factors: the soil degradation and the soil pollution. The accumulation of different harmful and/or toxic substances in the soil is well known. Heavy metals constitute a part of it. Metals in the soil and in the soil-solution are balanced. This balance depends on the type of the metal, on the pH, on the cation-band capacity of the soil, on the redox relations and the concentration of cations in the soil.
To be able to handle the metal contamination of the soil, it is important to estimate the form, the possible extension and the concentration of metals.
Of course, the different types of soils have different physical-chemical, biological and buffer capacity, they can moderate or reinforce the harmful effects of heavy metals. To draw general conclusion of the dispersion and quantitative relations on the metals originated from different contamination sources is hard, because in some emissive sources contamination is limited in small areas but on a high level, some others usually expand on larger areas, and as a result of equal dispersion, the contamination’s level is lower.
Heavy metals – unlike alkali ions – strongly bond to organic materials, or infiltrate in a kelát form. Their outstanding characteristic is the tendency to create metal-complex forms. Kelats take part in the uptaking and transportation of heavy metals. Heavy metals exert their effects mostly as enzyme-activators.
The metals cannot degrade in an organic way, they accumulate in living organisms, and they can form toxic compounds through biochemical reactions.
Lot of the heavy metals accumulate on the boundaries of the abiotic systems (air/soil, water/sediment), when physical or chemical parameters change, and this influences their remobilization.
Human activity plays a great part in heavy metal mobilization, results in the human origin of most biochemical process of metals.
To understand the toxic influence of accumulated metals of high concentration, their transportation from soils to plants or their damage in human health, must clearly defined and investigated.
For effective protection against soil pollution, the types and levels of harmful pollution to soil must identified, regarding legal, technical and soil-science aspects, preferable in a single way. Difficulties in this area mean that toxicity depends on loading, uptake, soil characteristics and living organisms (species, age, condition etc.), furthermore, local and economic conditions considerably differ. -
Investigations on Mud on Heavy Metal Contaminated Flood-Plain of Tisza
96-101Views:136At the beginning of the year 2000 subsequently to a mine accident high heavy metal content mud entered the catchment area of the Tisza and was transported through the whole Hungarian section of the river. The majority of the heavy metals had been bounded to the floating sediment that was deposited on the flood-plain soil during flood forming a new, 5-10 cm thick layer. In the mud samples collected after the flood there was a clearly visible dark grey layer with significantly higher heavy metal content that was formed by the pollution wave and it was sorruonded by a light layer. The upper layer of flood-plain soils are formed from this mud layer during the soil development process, so the amount of Lakanen-Erviö soluble heavy metals that correlate with bioavailable heavy metal content was examined as well. In this case only the lead content was significantly higher in the dark layer.
New mud samples were collected after the 2001 flood. Separate layers could not have been identified, their colour was similar to those of the previous year’s light layers’. Comparing to this light layer the total Zn and Lakanen-Erivö soluble metal content was significantly lower in the mud samples of the year 2001. While the proportions of total and Lakanen-Erviö soluble metal concentrations were equal in both of the layers regarding the elements, these ratios have significantly changed next year regarding Pb and Zn: the amount of Lakanen-Erviö soluble metals considerably decreased.
As a result of sequential extraction the heavy metal content was rather low in the water soluble and exchangeable and NaOH-soluble fractions, so heavy metals found in the mud could be released in greater amount only in case of a heavy acidification. -
Spatial Relationships Between pH and Vegetation Pattern in an Area Contaminated with Heavy Metals
140-143Views:102It is not possible to gain information on the risk factor representing the bioavailability and the mobility of the contaminants only on the basis of their total concentrations. Especially, in case of heavy metals, which can be charaterised with very different chemical forms and their mobil and mobilizable parts are determined by complex balances highly sensitive to the changing environmental conditions. Considering mine tailings, however, the toxic elements are basically in ore forms having low adsorption capacity, thus the heavy metal ion concentration in solution is governed mainly by the pH conditions. In Gyöngyösoroszi, the spatial distribution of the total heavy metal concentrations as well as that of pH values determining the bioavailable part of the toxic elements were estimated and by mapping the vegetation pattern, relationship was analysed among the total Zn, Cu, Pb and As concentrations, the pH and the species present. Results show that the presence of the certain plant species is highly determined by the pH on the mine tailing material, the highest vegetation density was found where the bioavailability of the toxic elements were considered the smallest as a result of the neutral pH. As a result, high diversity could be found even in places where the total zinc, copper, lead and arsenic concentrations were extreme. In addition, plant species could be identified, which are tolerant to toxic elements and present even if the pH is low and the bioavailable part of the heavy metals is relatively high.
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Potential use of bamboo in the phytoremediation in of heavy metals: A review
91-97Views:357There are many literature sources focusing on the phytoremediation of woody plants, but there are only few dealing with the phytoremediation of bamboo plants. Phytoremediation technology has the advantages of little disturbance to the environment and low remediation cost. Bamboo mainly exists in tropical and subtropical regions. As an energy plant, bamboo has a fast growth cycle, large biomass, simple cultivation, high economic efficiency, and convenient harvesting, which highlights the advantages of bamboo in phytoremediation. In addition, bamboo plants have good tolerance and uptake ability to heavy metals and have high application potential and development value in uptaking heavy metal contaminated soil. However, due to climate, temperature and other reasons, bamboo cannot be widely planted in most countries. Research status of remediation of heavy metal contaminated soil by bamboo plants is summarized. The feasibility of its application in heavy metal contaminated soil is discussed in this paper. Aiming at the shortcomings of existing research, bamboo plants have a prospect in the field of plant phytoremediation for the future.
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Classification of a diffuse heavy metal polluted mining site using a spectral angle mapper
119-123Views:128Characterization of heavy metal polluted abandoned mining sites is complicated, as the spatial distribution of pollutants often changes dramatically.
In our study, a hyperspectral data analysis of the Gyöngyösoroszi abandoned Pb-Zn mine, located in northern Hungary, where Záray (1991) reported serious heavy metal contamination, was carried out using ENVI 4.3. In this area, galena (PbS), goethite (FeO(OH)), jarosite (KFe3(SO4)2(OH)6), sphalerite ((Zn, Fe)S) and pyrite (FeS2) were the predominant minerals in the alteration zones was chosen as the target mineral.
Spectral angle mapper (SAM) and BandMax classification techniques were applied to obtain rule mineral images. Each pixel in these rule images represents the similarity between the corresponding pixels in the hyperspectral image to a reference spectrum.
As a result of hyperspectral imagery the distribution of pyritic minerals (sphalerite, galena) in the area was defined. Both of the mineral formations occur, especially in mine tailings, the area of the ore preparatory, and the Szárazvölgyi flotation sludge reservoir. According to the results, jarosite and goethite have similar distributions to sphalerite and galena. The results showed that hyperspectral remote sensing is an effective tool for the
characterization of Pb, Zn and Fe containing minerals at the examined polluted sites and for modelling the distribution of heavy metals and minerals in extensive areas.
This classification method is a basis of further detailed investigations, based on field measurements, to map the heavy metal distribution of the studied area and to quantify the environmental risks caused by erosion, which include DEM (digital elevation model) and climatic and hydrological data sources. Furthermore, it can be used primarily to support the potentially applicable phytostabilization technique and to isolate hot spots where only ex-situ remediation techniques can be applied. -
Applicability of hyperspectral technology for in situ phytoremediation
71-78Views:136The characterization of heavy metal polluted abandoned mining sites is a complicated assignment due to the variable spatial distribution of the pollutants, therefore complex integrated method is required in order to assess precisely the amount and the distribution of the contaminants. The examined area is flotation sludge reservoir of abandoned Pb-Zn mining site with serious heavy metal contamination. located in Gyöngyösoroszi, Northern Hungary.
The hyperspectral image of the flotation sludge is obtained by using a Digital Airborne Imaging Spectrometer DAIS 7915, in the frame of DLR HySens first Hungarian hyperspectral flight campaign (21/08/2002). Parallel to the flight campaign heavy metal content of soil samples were examined from the area of the flotation sludge. The analysis of hyperspectral data was verified by the examination of mine tailing samples by FPXRF (Field Portable X-ray Fluorescence spectrometry) (NITON XL-703).
Determinations of heavy metal containing minerals are based on the spectral profiles of the pixels of the area with using USGIS standard spectral profiles of the examined materials (galena, pyrite, sphalerite, goethite and jarosit).Applying the Spectral Angle Mapper with BandMax classification the distribution of minerals (galena, pyrite, sphalerite, goethite, jarosit) in the area was defined. The mineral formation occurs especially at the levees and the barren places of the Szárazvölgyi flotation sludge reservoir. Based on the statistic results of the samples, principal component analysis and correlation coefficient between the different metal content of the samples were calculated. The highest correlations were found between Pb-Zn, Fe-Zn and between Fe-Pb. This prove the results of the principal component analysis, where usually Pb, Zn, Fe introduce the main component.
Canopy analysis was also carried out with the hyperspectal image in order to classify the differences between vegetation types at the Szárazvölgy flotation sludge reservoir and analyse the applicability of it. Supervised classification methods were used to distinguish 8 vegetation types based on the spectral properties of the area. The results of the classifications were compared to a ground truth image, based on ortophoto, topographic map, and GPS based field data collection. According to results of the comparison, the paralellpiped classification method is proved to be appropriate method based on the overall accuracy of canopy classification, which was 54% due to heterogeneity of the vegetation.
The results of hyperspectral data and FPXRF analysis suggest that Pb, Zn and Fe containing minerals have similar spatial distribution in the examined and barren area.
Based on this study hyperspectral remote sensing is likely to be an effective tool for the characterization and modeling the distribution of Pb, Zn and Fe containing minerals at the examined heavy metal polluted sites. Further more, based on the vegetation analysis plant species for phytoremediation can be defined.
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Study regarding the influence of the nPK fertilizers use in long term trial on heavy metals concentration in wheat grains
107-109Views:125The paper presents research results obtained in stationary experiments, carried out at Agricultural Research and Development Station Oradea, regarding the influence of nitrogen, phosphorus and potassium fertilizers, on Cd, Pb, Cu, Zn and Ni concentration on wheat grains.
The minimum concentration of cadmium in wheat grains was recorded in the case of the unfertilized plot N0P0K0, 0.12 mg kg-1, and maximum value 0.22 mg kg-1, was registered at the fertilized plot with N160P80K120, relative difference relative to control was 84.2%.
Lead concentration had the lowest value in the unfertilized plot, the value (0.4 mg kg-1) being under the maximum allowed (1.0 mg kg-1). In case of the fertilized plot with N160P80K120, the lead concentration had the highest value, 0.47 mg kg-1, but even in this case it was located beneath the maximum limit allowed.
In all four systems of fertilization, copper has not exceeded the maximum allowed limit (5 mg kg-1), the values have been comprised between 1.68 mg kg-1 at the unfertilized plot and 2.81 mg kg-1 at the fertilized plot with N160P80K120. In other plots of fertilization copper had concentrations of 1.97 mg kg-1, at the fertilized plot with N80P40K40, and 2.78 at the fertilized plot with N80P80K80.
The lowest concentration of zinc, 26.47 mg kg-1, has been registered in the control N0P0K0. In the other fertilization plots studied, the zinc concentrations had the following values: 27.66 mg kg-1 (N80P40K40), (N80P80K80) 29.87 mg kg-1 and 33.62 mg kg-1 (N160P80K120).
Nickel has registered the lowest value in the unfertilized plot, 3.47 mg kg-1. The fertilized plot with N160P80K120 had the highest value 4.94 mg kg-1, with 42.39% higher compared to the control N0P0K0.
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Regulation in Hungary of the Use of Waste Water and Sewage Sludge in Agriculture
143-149Views:141Regulating the use of waste water and sewage sludge in agriculture in such a way as to prevent harmful effects on soil, vegetation, animals and man.
In European Union there is a Council Directive (86/278/EEC) on the protection of the environment, and in particular of the soil, when sewage sludge is used in agriculture.
In the enlargement process of the European Union the Hungarian Government created a new rule (50/2001. (IV. 3.) Government regulation) which regulate using of waste water and sewage sludge in agriculture. This Hungarian rule is legal and reconcilable with the Council Directive.
The Regulation lays down limit values for concentrations of heavy metals in the soil, in waste water, in sludge and for the maximum annual quantities of heavy metals which may be introduced into the soil.
Waste water, sludge and soil on which it is used must be sampled and analysed.
Sewage sludge must be treated for six months before being used in agriculture.
The use of waste water and sludge prohibited on grassland, on nature reserved areas, in ecological farming, and soil in witch fruit and vegetable crops are growing, with the exception of fruit trees.
The states soil conservation authority must keep records registering the following:
– the quantities of waste water and sludge produced;
– the composition and properties of sludge;
– the type of treatment carried out;
– the names and addresses of the recipients of the sludge and places where the sludge is to be used.
The Government every four years must prepare a consolidated report on the use of sludge in agriculture, specifying quantities used, criteria followed and any difficulties encountered. This report must be forwarded to the Commission.
Last but not least in the light of Member States reports, the Commission will if necessary submit appropriate proposals for increased protection of the soil and the environment. -
Intensity of free radical processes in the leaves of arboreal plants under act of industrial dust borne extracts
83-87Views:77The influence of industrial pollutants on the intensity of lipid peroxidation in the assimilatory organs of arboreal plant was investigated. The differential changes of the probed indexes are set depending on the species. Information is got can testify to participation of lipid peroxidation products in forming of reactions-answers of arboreal plants on influence of industrial dust borne extract with content of heavy metals. Determination of level and rates of accumulation of Zn, Ni, Pb and Cd, in the leaves of arboreal plants in the conditions of different
contamination level allowed to take species to two groups. To the first (phytoextraction potential exceeds a base-line level in 10 times) belong Populus bolleana Lauche, P. italica (Du Roi) Moench, Picea pungens Engelm and Sorbus aucuparia L. To the second (exceeds a base-line level from 5 to 10 times) belong Acer negundo L., Aesculus hippocastanum L., Betula pendula Roth and Tilia cordata Mill. The most substantial increase of peroxidation secondary product content (more than in 2.5 times) is peculiar for B. pendula, A. hippocastanum and P. pungens Engelm., that well conforms to the rates of heavy metals translocation, it has however species-specific character. -
The special questions of nutrition of forest plants
83-88Views:69Some physiological effects of bacteria containing fertilizer and some wood ash were examined in the experiments. The minimization of the use of chemicals in agriculture has been an ongoing challenge. One option lies in the intenzification of soil life. The release of organic matters by the roots and bacteria play a significant role in the uptake of minerals. The main problem to usilize wood ash in agriculture is its heavy metal contents. The
solubility of heavy metals is very low, therefore there is no risk to use the wood ash in the agriculture and in the horticulture according to our experiments. The wood ash and biofertilizer contains several micronutrients in an optimum composition for forestry and agricultural plants. -
Examination of the possible role of biofertilizers and wood ash in the nutrient supply of plants
87-95Views:98Some physiological effects of bacteria containing fertilizer and some wood ash were examined in the experiments. The minimization of the use of chemicals in agriculture has been an ongoing challenge. One option lies in the intenzification of soil life. The release of organic matters by the roots and bacteria play a significant role in the uptake of minerals. The main problem to usilize wood ash in agriculture is its heavy metal contents. The solubility of heavy metals is very low, therefore there is no risk to use the wood ash in the agriculture and in the horticulture according to our experiments. The wood ash and biofertilizer contains several micronutrients in an optimum composition for forestry and agricultural plants.
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Food safety of plant origin food
161-164Views:202Expectation regarding changes related to food production, transportation, distribution and marketing have changed considerably in several regions of the world over the past decades. It is especially true for highly industrialized countries where not only the food security is important but the food safety is essential too. The concentration of production – processing – distribution involves the danger on the one hand products of unsuitable quality from point of view of nutritional physiology and the other hand ones that may contain substances harmful to human health will become widespread among consumers. We investigated the heavy metal, pesticide remains and mycotoxin content of different plant products.
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Changes in toxic elements content of soil after sewage sludge treatment in energy willow plantation
7-10Views:150The primary purpose of our experiment was the solution of municipal excess sludge treatment by a renewable energy resource used willow (Salix viminalis L.) plantation. Tests were carried out to state whether the applied sewage sludge has caused any accumulation of the toxic elements in the studied soil layers, and - based on the results –to see whether the plantation is suitable for the treatment of municipal sewage sludge.
The excess sludge (sludge before dewatering) is beneficial for the willow, because it contains a 3–5% dry matter and therefore, a lot of water, too. This high water content ensures the high water amount needed for the intensive growth of the willow. On the other hand, the wastewater treatment plant can save the dewatering cost which corresponds to about 30% of the water treatment process costs. The amounts of the sprinkled sewage sludge were calculated on the basis of its total nitrogen content. Treatments were the followings: control, 170 N kg ha-1 year-1 and 250 N kg ha-1 year-1. The mean values of the toxic element concentrations in the sewage sludge did not cross the permitted limits of the land accommodating.The measured toxic element values of the soil were compared to the limits of the 50/2001. (IV.3.) Government Regulation.The sprinkled sewage sludge on the bases of the total N content did not cause accumulation of heavy metals in the soil and the treated plants were also healthy without any signs of toxicity.
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Effect of arsenic treatments on physiological parameters of sunflower and maize plants
81-84Views:216The environment is contaminated with heavy metals and other toxic compounds. One of the most important toxic element is the arsenic (As).
The objective of our study was to investigate the effect of As on fresh and dry weight of sunflower and maize in the early growth phases.
Seedlings were grown in climate room on nutrient solution which were treated with 3, 10 and 30 mg kg-1 arsenic. The plants were treated separately with As(III) and As(V). After 14 day, changes in fresh and dry weight of maize shoots and roots were recorded. In the case of sunflower these parameters were measured after 21 day.
The applied As(III) and As(V) decreased the fresh and dry mass of the shoots and roots of seedlings, especially at concentration 30 mg kg-1. We can draw the conclusion that the treatments of the maize and sunflower roots with arsenic had negative effects on the biomass accumulation. We found that the sunflower plants are more sensitive to arsenic toxicity than maize plants, and all data demonstrate that the As(III) is more toxic to these plants than the As(V).
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Overview of the evolutionary history and the role in citric acid production of alternative oxidase
83-88Views:148All organisms are exposed to countless environmental effects, which influence in a disadvantageous way their life processes. They continuously adapt to the changing conditions and respond to the stress impacts by defence mechanisms. Through different signal transduction pathways they are able to increase or decrease the expression of their genes and consequently modify their metabolic processes. My interest focuses on alternative oxidase (AOX) enzyme whose expression is often increased under biotic and abiotic stress. The so far proven and putative functions of the AOX play a role in the ability of organisms to adapt to different conditions, such as heavy metals accumulation, pathogenic infection, oxidative stress and lack of oxygen or nutrients.
AOX is a member of the di-iron carboxylate protein family. Members of the di-iron carboxylate protein family are present in all kingdoms of life. They are considered to have ancient origin. It is believed that their sulfide-resistant and oxygen-reducing ability played a role in the survival of organisms during the transition between the anaerobic and the aerobic world. It is assumed that the AOX arose in eukaryotes through a primary endosymbiotic event, and this event made possible the development of mitochondria. Afterwords, vertical inheritance, and secondary and tertiary endosimbiotic events led to its spread among eukaryotes. It is assumed that bacteria obtained AOX by horizontal gene transfer from plants.
AOX-catalyzed alternative respiration plays an important role in the operation of energy-producing and biosynthesizing system of microorganisms. In these cases, the regeneration of reduced cofactors is an essential condition, and therefore may be rate-limiting for biotechnological processes, including the citric acid production.
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Physiological examination on cadmium sensitvity of some maize and sunflower varieties
169-173Views:112Cadmium is one of the most dangerous heavy metals, which may cause serious problems in certain physiological processes of living organisms even in small amounts. In our work we analysed how cadmium affects some physiological parameters of different maize and sunflower hybrids. The chlorophyll contents and the morphological changes of the root were examined. We received different results in terms of the cadmium tolerance of these two plants.
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Effect of arsenic treatments on the element content of green peas
203-208Views:237The agricultural environment is contaminated with heavy metals and other toxic elements, which means more and more threats. One of the most important toxic element is the arsenic (As).
The objective of the study was to investigate the effect of As-treatments on the element content of the different parts of the green peas (root,stem, leaf, pod, pea) in the 4. phase of the plant development. Plants were grown in green house. Arsenic was applied in a form of arsenate (As[V]) and the plants were treated with 0, 3, 10, 30, 90 and 270 mg kg-1 arsenic.
According to the results the Ca content of root and pod was increased in the case of the 3 mg kg-1 As-treatment, after that decreasing tendency was observed. In the case of the 270 mg kg-1 As-treatment, the Ca content in the root was increased, because some element is able to concentrate in the lower biomass. The Ca-content of stem and leaves was reduced when the plants were treated with more than 30 mg kg-1 As. The lowest As-treatment (3 mg kg-1) increased the Na content in the root, stem and leaves, however in the case of the higher As-dose, decreasing tendency was observed. In the case of the generative plant parts the 3 mg kg-1 As-treatment also increased the Na content, nevertheless in the case of the higher As-treatments lower Na content was measured, however in the case of the highest As-treatment (270 mg kg-1) the Na content was increased in the generative plant parts, probably the Na was concentrated in the lower biomass. In the case of the 90 and 270 mg kg-1 As-treatment the Mo-content also was increased in the generative plant parts. The 270 mg kg-1 As-treatment caused a similar tendency in the case of the generative plant parts as a result of the lower biomass. In the case of the pod and leaves, the lower As-doses did not cause significant changes.
The Mo content was increased in the root and pea when the plants were treated with 3 mg kg-1 As, but in the case of the higher treatments it was decreased. In the case of the stem it was reverse, the lowest As-tretament (3 mg kg-1) decreased, nevertheless the further As-doses increased the Mo content. -
Role of living bacteria and other amendment in early development of maize
53-56Views:126Different bacteria and wood ash, as a possible micro-nutrient, and liming material, was examined in our experiment on the early growth of corn seedlings.
The development of renewing energy resources includes the use of energy grasses and energy forests. The intensive land use in forestry and in agriculture may cause the acidification of soils due to the harvest, or leaching of cations. To maintain the sustainability of soils necessary to maintain it’s the buffer capacity, and pH. Beside the lime the wood ash can is one of the most effective sources to provide the sustainability of intensive land use. The soil born micro organisms play a significant role in the maintenance of soil quality. The bio fertilizer, that contains soil originated bacteria (Azotobacter, and Bacillus sp.), was used in the experiments. The plants release several organic acids by their roots lowering the soil pH, and make more available the sparingly soluble minerals. The amounts of released organic matter depend on stress intensity, as the high pH is. The soil life has a significant role to keep the soil conditions on sustainable level, since there are several similarities in nutrient uptake mechanism between the bacteria and higher plants. Advantageous effects of bio-fertilizer were observed in our experiments.
We came to the conclusion that the use of wood ash is recommended instead of lime for the improvement of acidic soils, on the evidence of its pH increasing effect. The wood ash contains several micronutrients in an optimum composition for forestry and agricultural plants. The solubility of heavy metals is very low; therefore there is no risk to use the wood ash in the agriculture and in the horticulture by our experiments. The retardation of growth at higher ash doses can be explained by the modification effect to the soil pH, as far as the original soil pH was pH 6.8, and when ash was given to the soil, the pH increases to 7.8 pH, that is unfavourable for the uptake of most nutrients.