Contaminated Soils

Sources of Arsenic in Soil

Arsenic Geocycle The Environment

Arsenic occurs naturally as an element, ranks as the 20th most occurring trace element in the earth's crust (NRC 1977) and is widely distributed in the environment. The ultimate source of arsenic on the Earth's surface is igneous activity (Nriagu 1994). Arsenic is widely spread in the upper crust of the Earth, although mainly at very low concentrations, with arsenic concentrations in soil ranging from 0.1 to more than 1,000 ppm (mg kg-1). In atmospheric dust, the range is 503,400 ppm. In...

Ecological Classification of Earthworms

Earthworm Skin Morphology

An earthworm substantially enhances physical, chemical, and biological characteristics of soil through their feeding, casting, and burrowing activities. Different earthworm species differ in their ecological strategies which influence main physical features of soil (soil aggregation and porosity) in different degrees and therefore classify them as epigeic, endogeic, and anecic (Lee 1985 Lavelle and Spain 2001 Karaca et al. 2010a Kizilkaya et al. 2011) (Fig. 21.1). Epigeic species such as...

Forms of Arsenic in Soil

Generally, As concentrations in uncontaminated soils seldom exceed 10 mg kg-1. However, anthropogenic sources of As have elevated the background concentration of As in soils (Adriano 2001). For example, in areas near As mineral deposits, As levels in soils may reach up to 9,300 mg kg-1 (Ashley and Lottermoser 1999). Depending on the nature of the geogenic and anthropogenic sources, As concentration in soils can range from < 1 to 250,000 mg kg 1. However, there is a large fluctuation among...

Mechanism of Animal Remediation

Animal here mainly refers to earthworm, because it is one of the most important soil organisms and plays an indispensable role in improving soil quality (Sriprang et al. 2002, 2003 Kashiwa et al. 2001 Fox et al. 1982). By their feeding, burrowing, excreting, and metabolic redox material, both soil texture and nutrition content are improved. Chemical groups such as -COOH and -CO are generated and exuded, which acidify soil and activate heavy metals. Several kinds of gel material are also...

The Biological Essentiality of Trace Elements

Essential Trace Elements

There are three criteria to say whether a trace element is essential for the normal growth of plants or not Fig. 1.2 Typical dose-response curves for (a) essential trace elements (micronutrients) and (b) nonessential trace elements (modified from Alloway 1995) Fig. 1.2 Typical dose-response curves for (a) essential trace elements (micronutrients) and (b) nonessential trace elements (modified from Alloway 1995) (a) The plant can neither grow nor complete its life cycle without an adequate supply...

References

Amrhein Ch, Haghnia GH, Kim TS, Mosher PA, Gagajena RC, Amanios T, de la Torre L (1996) Synthesis and properties of zeolites from coal fly ash. Environ Sci Technol 30 735-742 Baccouche A, Srasra E, El Maaoui M (1998) Preparation of Na-P1 and sodalite octahydrate zeolites from interstratified illite-smectite. Appl Clay Sci 13 255-273 Belviso C, Cavalcante F, Fiore S (2008) The zeolites synthesised in contaminated soil treated with coal fly ash. What is their role 33rd International geological...

The Heavy Metal Plants Metallophytes

Metallophytes

A botanist can immediately identify a habitat as heavy metal soil polluted by high concentrations of Zn, Pb or other heavy metals by the composition of the plants. In Central Europe, most heavy metal soils carry four to six typical metallophytes. Highest Zn-concentrations are endured by spring sandwort (Minuartia (Alsine) verna, Fig. 2.1h) of the Caryophyllaceae which otherwise occurs only, although abundantly, on chalk meadows and rocks in alpine regions of Europe above the timberline. The...

Phytoremediation of Heavy Metal Polluted Soil

Phytoremediation is an integrated multidisciplinary approach to the cleanup of contaminated soils, which combines the disciplines of plant physiology, soil chemistry, and soil microbiology (Cunningham and Ow 1996). These contaminants include heavy metals, radionuclides, chlorinated solvents, petroleum hydrocarbons, PCBs, PAHs, organophosphate insecticides, explosives, and surfactants (Khan et al. 2004). This technique involves the use of green plants to decontaminate soil, water, and air. Its...

Introduction

Since the industrial revolution, anthropogenic impacts have caused more and more hazardous heavy metals' releasing to environment. Soils, being the basic and most essential part of the ecological system, are heavily contaminated, too. Until now over 20,000,000 acres of farmland in China have been contaminated by heavy metals such as Sn, Cr, Pb, and Zn, which account for almost one-fifth of the total arable farmland area. Every year, China suffers a 10,000,000 tons' loss of crop output due to...

Arsenic Tolerance and Detoxification Mechanisms in Plants

Gupta, Sudhakar Srivastava, H.G. Huang, Maria C. Romero-Puertas, and Luisa M. Sandalio Arsenic (As) is a widely distributed metalloid in the earth's crust with an average concentration of 2 mg kg Inorganic arsenic is a class 1 carcinogen. There is widespread chronic As poisoning in regions of Asia and elsewhere, due to the consumption of drinking water with geo-genically elevated As content, and the situation is worst in the densely populated flood plains and deltas of South and...

Cadmium Metal Detoxification and Hyperaccumulators

Increasing anthropological practices have led to the addition of a highly toxic metal, cadmium, into the natural environment that affects the overall growth and metabolism of plants (Shah and Dubey 1998 Agrawal and Sharma 2006 Shah and Nongkynrih 2007). Cadmium toxicity can elicit a variety of adaptive responses that have been comprehensively reviewed by Toppi di Sanita and Gabbrielli (1999). Bioaccumulation of such toxic metals in the plants poses a risk to human and animal health (Wang et al....

Remediation of Heavy Metals From Soils

Heavy metals can not be destroyed biologically since there is a lack of degradation or change in the nuclear structure of the element. Such metals can only be transformed from one oxidation state or organic complex to another (Garbisu et al. 2002). As such, the remediation of heavy metal contamination in soils is more difficult. Until now, the methods namely excavation and land fill, thermal treatment, acid leaching and electroreclamation used for their remediation are not suitable for...

Plant Growth Promoting Rhizobacteria

The rhizosphere, which is a layer of soil affected by roots and has a greater amount of microorganisms compared to surrounding bulk soil (Lugtenberg and Kamilova 2009). PGPR is defined as bacteria living the rhizosphere and beneficial to plants (Kloepper et al. 1980). PGPR improve plant health and stimulate plant growth and reduce diseases (Solano et al. 2008 Yang et al. 2009). Inoculation of plants with microorganisms may diminish toxicity of heavy metals to plants in polluted soil (Madhaiyan...

Microbial Transformation of Arsenic

Arsenic And Cellular Respiration

Depending on the physical-chemical conditions of the environment, some arsenic compounds can be easily solubilized in water and taken up by microorganisms, resulting in high levels of bioavailability. Microorganisms have developed various strategies to counteract arsenic toxicity firstly, active extrusion of arsenic secondly, intracellular chelation (in eukaryotes) by various metal-binding peptides including glutathione (GSH), phytochelatins (PCs), and metallothioneins (MTs) thirdly, arsenic...

Plant Taxonomy and Metal Phytoremediation

Gawronski, Maria Greger, and Helena Gawronska Plants during 400 million years of evolution often were exposed to extreme environmental conditions. Plants, as organisms of sessile style of life, have developed unique defense mechanism(s) and strategies existing only in that group of organisms. As a result among all higher organisms only plants are able to survive in very polluted sites and tolerate high accumulation of toxic compounds in their tissues. They can thrive in soil, water...

Phytoremediation

Heavy metal uptake by plants is a less-expensive method Khan et al. 2000 . Bioremediation is defined as the use of organisms for the treatment of soil pollution Leyval et al. 2002 . Phytoremediation can be defined as the use of plants to extract, sequester and or detoxify pollutants through physical, chemical and biological processes Jing et al. 2007 Glick 2003 . Phytoremediation is a comparatively new approach, an environmentally friendly technique, and an emerging technology for removing...

Aspects of the Use of Metallophytes to Remediate Soils Polluted by Heavy Metals

Phytoremediation has been reviewed (Salt et al. 1998 Pilon-Smits 2005) Maerques et al. 2009 Muthukumar and Bagyaraj 2010). It comprises stabilization of soils devoid of plants due to heavy metal toxicity and extraction of heavy metals by plants. Volatilization and degradations have a role in the removal of other pollutants but not in the case of heavy metals. However, Hg and the toxic metalloids As and Se may be chemically converted to more readily extractable or volatile compounds. It is...

Problems in Maintaining Metal Homeostasis

When in contact with organic material, metals tend to bind to specific functional groups, or ligands, of the organic molecules. The four classes of functional poly-peptide-derived or endogenous ligands recognized in plants are (a) amino groups at the N terminus (b) carboxylate groups at the C terminus (c) carbonyl and amide groups of the main amino acid chain and (d) side groups of the main amino acid chain (e.g., amide, amino, carboxyl, hydroxyl, imidazole, phenol, selenol, sulfide, thiol...

Subcellular Localization of Cu in Elsholtzia splendens

One of the most important principles of heavy metal tolerance and detoxification in plant cells is its selective distribution, which could avoid damaging relatively significant organelles. The cell walls of plants have the capacity to bind metal ions in negatively charged sites (Macfie and Welbourn 2000). Therefore, plant cell walls could be a critical defensive strategy of plants to heavy metal stress (Branquinho et al. 1997). In addition to cell wall compartmentation, transport of metal ions...

Microorganism Based Remediation

Selective pressures from a metal-containing environment have led to the development of resistance systems in microorganisms to virtually all toxic metals (Rouch et al. 1995). These systems are mostly plasmid-mediated and very specific and have been found in virtually all eubacterial groups studied (Silver and Misra 1984 Ji and Silver 1995). These reports included mostly aerobic microorganisms, with prominent examples being resistance in Staphylococcus sp., Escherichia coli, Pseudomonas...

Earthworm Distribution in Soil

In general, there are considered to be around 6,000 species of earthworms (Fragoso et al. 1999 Lavelle and Spain 2001). Apart from extreme environments such as desert and glacial soils, earthworms can inhabit a wide variety of soil environments including agriculture, forest, and pasture ecosystems. The size of adult earthworms ranged from few mm to 2 m while their body mass changes between 10 mg and 1 kg. Giant earthworm species usually inhabit in tropical regions of southern hemisphere such as...

Phytoremediation of Heavy Metal Pollution in Soils 2051 Sugar Cane

Heavy metal pollution is a worldwide problem. Phytoremediation is an effective and low-cost interesting technology. Sugar cane (Saccharum officinarum L.) may be a promising candidate for phytoremediation on metal-contaminated soils due to its greater biomass, faster growth and moderate take-up and accumulation of heavy metals such as Cu, Cd, Se, Pb, and Mn. As a follow-up processing of sugar cane, bagasse may adsorb heavy metal ions in aqueous solutions and sugar cane juice may be used to...

Microscopic Observations

Scanning Electron Microscope (SEM) images of zeolite particles directly synthesized in soil in the presence of polluting metals are reported in Fig. 22.4. These zeolite minerals have been characterized for chemical composition and size by using an SEM automated single particle analysis (ASPA) method (Terzano et al. 2007). A summary of these data is reported in Table 22.2. Zeolite X (Fig. 22.4a) synthesized at 30 C and 60 C corresponds to a mineral characterized by the general formula...

Metal Immobilization

Immobilization is one of the most common mechanisms of plant adaptation to elevated concentrations of heavy metals. The avoidance of metal stress may be achieved by the binding of metal ions in the apoplast which prevents their internal-ization. Metals may be deposited in cell walls as metalloorganic complexes formed with ligands present in this compartment (e.g., polysaccharides and organic acids). For example, the binding of Pb in cell walls has been demonstrated in the free-floating...

Order Poales

Among monocotyledons this order is dominating in the number of families with species possessing high capabilities for heavy metal uptake. Most distinguished among them is the Poaceae family with quite a long list of cultivated species such as cereals and high biomass producing grasses that could be considered as good phytoremediants. Grass family is one of the most important for phytoremediation of heavy metals and organic pollutants such as PAHs and petroleum hydrocarbons. The advantage of...

Microbially Enhanced Phytoremediation

Hyperaccumulation transfers dissolved As from soils or waters into plant tissues. A combination of hyperaccumulation with phytoremediation can remove or contain As, offering an effective, environmentally nondestructive and cheap remediation method. However, a key issue for an effective phytoremediation process, especially phytoextraction, is to enhance pollutant phytoavailability and to sustain adequate pollutant concentrations in the soil solution for plant uptake (Lombi et al. 2002). In...

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Aa v aaa0bv a a . vv a a aaa a a v v vaaa v aa a vaaaa a aav v aaa v a a hc a a w aaa Fig. 22.6 Schematic representation of the HM stabilization processes in treated soils 1) Si-Al-containing materials are added to HM-polluted soil together with alkalizing agents 2) HM are precipitated or coprecipitated in an amorphous aluminosilicate phase according to the reaction conditions, 3) crystalline zeolites can form over time and trap HM precipitates inside their internal cavities, and or 4)...

Genes and Their Expressions Upon Heavy Metal Stress in Plants

It is often stated that metal tolerances are strictly metal-specific however, the situation is often not so simple as this (see Schat and Vooijs 1997). Any combined tolerance to different heavy metals in a metallophyte could result from the sum of different metal-specific mechanisms or from less-specific mechanisms that pleiotropically confer tolerances to different metals. Work with Silene vulgaris (Schat and Vooijs 1997) showed that tolerance to Cu, Zn and Cd is under nonpleiotropic,...

Effect of Metals on Photosynthesis in Aquatic Macrophytes

Photosynthesis, which is the basis of all food chains up to human life, is the site of direct or indirect action of heavy metals (for a review, see Mysliwa-Kurdziel et al. 2002, 2004 Mallick and Rai 2002 DalCorso et al. 2008). As to the direct effects of heavy metals on photosynthesis, damage to the reaction centers of photosystems (PS I and PS II), the water splitting complex, the LHCII antenna complex, cyt b6f, and other components of the photosynthetic transport chain have been observed....

Cadmium Fractionation in Calcareous Soils

Sequential extraction procedures have been widely used for examining the physico-chemical forms of heavy metals, which has been described as fractionation, and are important tools for investigating the mobility and environmental ecotoxicity of these elements in soils. Recently for the assessment of the contamination levels of heavy metals the total concentration is considered, although it provides no insight into metal mobility and bioavailability. The bioavailability of metals in soil is...

Salinity and Cadmium Fractionation

Very limited information is available on the effect of salinity on the bioavailability and fractionation of cadmium in calcareous soils. In an experiment, Abbaspour et al. (2007) evaluated the effects of salinity on distribution of added Cd among soil fractions in a calcareous soil from Central Iran. In this work, soil was treated with 20 mg Cd kg-1 as Cd(NO3)2-4H2O and 50 mmol kg-1 of NaCl, and then incubated at 60 water-holding capacity (60 WHC) and constant temperature (25 C) for 12 weeks....

Description of the Stabilization Process

All the data available in the literature provide sufficient information to hypothesize concurrent physicochemical phenomena responsible for HM stabilization when promoting zeolite synthesis in soil. First of all, the precipitation of metal hydroxides, owing to the high increase in pH after the addition of alkali-activated Si-Al-containing materials, is certainly the main process responsible for the observed marked reduction in HM solubility. However, processes such as chemisorption and...

The Development of Crop Hyperaccumulators

Another new viewpoint toward phytoremediation is that adequate attention must be paid to the development of crop hyperaccumulators, termed by the author as crop accumulators , such as wheat, maize, and rice (Heaton et al. 1998 Bizily et al. 2000 Ruiz et al. 2003 Lee et al. 2003). In other words, investigations of other noncropaccumulators species would be of little significance in application. A large area of farmland in the world is contaminated by heavy metals and needs remediation....

Order Rosales

This is one of the most important order in human life, cultivated mainly for food and ornamental purpose. Rosaceae is the biggest family in this order, possessing above average tolerance to pollution several species but generally not so high such as some of those described earlier. Tolerant species from this family are mainly ornamentals and often cultivated in polluted urban areas. Roses, tolerant to the pollution, are very often cultivated on the median strips dividing traffic directions with...

Natural Hyperaccumulators

Several plant genera, as well as some microbes and fungi, are natural hyperaccumulators of heavy metals. It is suspected that their enhanced abilities to accumulate, translocate, and detoxify and sequester heavy metal ions evolved in some taxa to protect against disease and insect herbivores, similar to the function of glucosinolates (Salt 2006). The Brassicaceae family contains the largest number of hyperaccumulators with 11 genera (Prasad and Freitas 2003). Thlaspi species can accumulate...

Engineered Microbes for Arsenic Remediation

The use of microbial biotechnology in the field remediation of metal contaminated soils with special reference to arsenic is a promising approach. The use of engineered microbes as selective biosorbents is an attractive green cure technology for the low cost and efficient removal of arsenic (Singh et al. 2008a, b). Although efforts have been reported in engineering microbes for the removal of cadmium or mercury by expressing metal-binding peptides such as human MTs (Pazirandeh et al. 1995 Li et...

Transport of Zn Across Membranes 741 Diversity of Zn Transporters

Plant cells contain several types of membrane transporters of Zn metal tolerance protein (MTP), ZRT1 IRT1-like protein (ZIP) (also known as zinc-iron permease), and heavy-metal ATPase (HMA) (P1B subgroup of P-type ATPase) (Kramer et al. 2007). These are different in their structure and transport mechanism. ZIP is a passive transporter that facilitates the downhill flow of Zn until its electrical and or concentration gradient is dissipated. MTP is a subfamily of the cation diffusion facilitator...

Initial Steps of Copper Detoxification Outside and Inside of the Plant Cell

Ivanova, and Vladimir V. Kuznetsov Increasingly high technogenic load on the environment raises a problem of strategies and mechanisms of plant adaptation to abiotic stressors, among which heavy metals (HM) occupy a specific place. Contamination of vast territories with HM acquires more and more threatening character. According to their toxicity, all HM are arranged in the so-called Irving-Williams series, where Cu takes the first place corresponding to the...

Proteomic Studies in Response to Heavy Metal Toxicity

Proteomics is a high-throughput analytical technique that has been applied to the study of a number of biological processes, such as protein identification, determination of the protein expression profile during normal and stressful conditions, analysis of posttranslational modifications PTMs , and studies of protein-protein interactions. The major advantage of proteomics is that it focuses on the functional translated portion of the genome. Thus, the use of proteomics is expanding rapidly in...

Sulfur Metabolism as a Support System for Plant Heavy Metal Tolerance

Preuss, and Joseph M. Jez Sulfur is a critical nutrient for the growth and development of plants, as well as all living organisms, and it plays a central role in plant defense responses against biotic and abiotic stresses. It is a component of the amino acids cysteine and methionine, cofactors, metal clusters, and a diverse range of primary and secondary metabolites, such as glutathione, phytochelatins, and glucosinolates that protect plants from oxidative and...

APS Reductase

APS Reductase (APSR), responsible for the reduction of APS to sulfite and AMP, is among a group of genes upregulated in response to cadmium stress (Minglin et al. 2005). Transcription of APSR, as well as ATPS, increases in response to depletion of cysteine and glutathione in cadmium-stressed B. juncea (Heiss et al. 1999). The coordinate changes resulted in increased cysteine concentrations, especially in the roots, supporting the importance of APSR in regulation of cysteine levels. Although...

Impact of Cu on the Structure of Elsholtzia splendens

Structure is the foundations of function. Metal-induced alterations at the structural and ultrastructure level might reflect the extent of metal toxicity stress. In this part, structure changes of Elsholtzia splendens under Cu stress at the tissue and cell level were introduced based on the research of Ni (2004) and Peng et al. (2005c). 17.3.3.1 The Impact of Copper on Tissues Structure of Elsholtzia splendens Micromorphology of root, stem, and leaf of E. splendens under Cu stress (50 mmol L1)...

Polymetallic Contamination

Sources of monometallic environmental contamination are rare and have a predominantly local character, where there are mainly plants using specific metal salts for technological processes like tanneries (Cr), some wood impregnation plants (Cu, As, and Cr), and the car battery industry (Pb). Most pollution, however, is emitted from polymetallic sources, among which the mining and smelting industries have the greatest impact. So heavy metal effects on water plants should be investigated not only...

Heavy Metal Tolerance Mechanisms in Plants

Heavy metals such as Cu and Zn are essential for normal plant growth, although elevated concentrations of both essential and nonessential metals can result in growth inhibition and toxicity symptoms. Some plant species, however, have evolved tolerant races that can survive and thrive on such metalliferous soils, presumably by adapting mechanisms that may also be involved in the general homeostasis of, and constitutive tolerance to, essential metal ions as found in all plants. Plants have a...

Heavy Metal Sequestration

Various metabolites and ions are stored inside the vacuoles. Vacuolar sequestration of a number of heavy metals such as Cd, Ni, As, and Zn is known, which diverts metal ions from metabolically active compartments (cytosol, chloroplasts, and mitochondria) and minimizes the harmful effects of metal ions to vital cellular processes. Transporters are present in internal membranes to allow regulation of stored metals in organelles. Active accumulation of most of the metal ions is driven by the...

Initial Steps of Intracellular Copper Detoxification

As was mentioned earlier, essentially all Cu ions are present in the cytosol in the bound form (Changela et al. 2003 Kramer et al. 2007). Thus, after Cu ions transfer across the plasma membrane with the help of membrane transporters, they are immediately subjected by chelating. The basic components of the defense system in the cytosol are S-containing ligands phytochelatins (PC) and metallothioneins (MT). MT belong to the group of cysteine-rich proteins (8-10 kDa) encoded by the family of...

Arsenic Toxicity of Food Chain

Arsenic can enter through the food chain through drinking water or the food crops raised in arsenic contaminated soil (Fig. 12.2). There are evidences of elevated arsenic levels in the rice grain in regions of West Bengal and Bangladesh where rice fields are irrigated with arsenic contaminated waters (Rahman et al. 2009 Duxbury et al. 2003 Williams et al. 2005 Islam et al. 2004 Khan et al. 2009). Apart from rice crop, elevated levels of arsenic contamination in vegetables was also reported from...

Earthworm Heavy Metal Relationships and Accumulation and Detoxification of Heavy Metals by Earthworms

Although heavy metals exist lithologically in the ground, their concentrations in soil increase through various industrial emissions Cemek and Kizilkaya 2006 , commercial fertilizers, Karaca et al. 2002 and sewage sludges Kizilkaya and Bayrakl 2005 . Depending on soil characteristics, heavy metals accumulated in food chain and this affects soil life and especially biological-biochemical reactions negatively Kizilkaya and Askin 2002 Kizilkaya et al. 2004 Karaca et al. 2010b . The earthworms are...

Agricultural and Horticultural Materials

Agricultural practices constitute very important nonpoint sources of metals which make significant contributions to their total concentrations in soils in many parts of the world, especially in regions of intensive farming. According to the data obtained by the Lowestoft Laboratory of the Ministry of Agriculture, Fisheries and Food (MAFF 1986), the main sources are as follows Impurities in fertilizers Cd, Cr, Mo, Pb, U, V, and Zn Sewage sludge especially Cd, Ni, Cu, Pb, and Zn (and many other...

Heavy Metal Soils

Heavy metals have a molecular mass > 5.0 g cm-3 which is distinctly higher than the average particle density of soils (2.65 g cm-3). Several heavy metals such as iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), cobalt (Co), or molybdenum (Mo) are essential for the growth of organisms. Others have a single function and only in some organisms such as vanadium (V) in some peroxidases and in V-nitrogenases or nickel (Ni) in hydrogenases. The remainder of the heavy metals is always toxic to...

Strategies Employed by the Metallophytes to Cope with High Concentrations of Heavy Metals at the Whole Plant Level

Heavy metal tolerance has been developed by plants of totally unrelated taxonomic affinities. It is frequent in Brassicaceae, and also seen in Caryophyllaceae, Plumbaginaceae, Violaceae, Asteraceae, Poaceae, and others. Over 34 different plant families have developed heavy metal tolerant species (Verbruggen et al. 2009). Heavy metal tolerance is thus one of the clear-cut examples of convergence in biology. Therefore, it is not surprising that the strategies to cope with the excess of heavy...

Mechanism of Chemical or Physical Remediation

Chemical or physical method is early used and even endemically commercialized in America. Physical methods (e.g., soil leaching method and absorbent fixation) and chemical methods (e.g., bioreduction and chelate extraction) are used in practice. In these methods, the use of chelators cannot be avoided. By adding synthetic Fig. 4.1 EDTA-Pb complexes. Dotted bonds to Pb are coordinate chelators such as ethylenediamine-tetraacetic acid (EDTA), both the solubility and bioavailability of heavy...

Phytochelatins

Phytochelatins (PCs) are small metal-binding peptides found in plants and are well documented in the literature (Grill et al. 1986a Mehra and Winge 1988 Meuwly et al. 1995 Klapheck et al. 1994 Chen et al. 1997). PC formation uses glutathione (Grill et al. 1989), homoglutathione, hydroxymethyl-glutathione (Klapheck et al. 1995), or g-glutamylcysteine (Hayashi et al. 1991). It is catalyzed by phytochelatin synthase (PCS), a constitutive enzyme requiring posttranslational activation by heavy...

Cadmium Detoxification

Calcareous soils represent potential adsorptive surfaces for heavy metals by means of carbonate and phosphate components. The presence of carbonate minerals in soils directly affects the mobility and reactivity of heavy metals through the surface interaction and indirectly through their affects on soil pH (McBride 1980). Phos-phatic components are the important reaction products of added phosphorus with calcium carbonate as well as in calcareous soils, depending upon Ca P ratio (Griffin and...

Remediation Techniques

Soil remediation is one of the permanent alternatives to remove metal contaminants from soils. The remediation of metal-contaminated soils involves physical, chemical, and biological techniques. Physical techniques are based on approaches generally applied in mining and the mineral processing industry to extract the desired metal-bearing particles from mineral ores (Dermont et al. 2008). These approaches involve mechanical screening, hydrodynamic classification, gravity concentration, froth...

Soil Sediment Continuum

Soils and sediments are connected or interlinked by a hydrological phase and these are functionally similar and share a number of common features. In fact, there is no clear borderline between soils and sediments, because both are interlinked by Fig. 18.3 Soils and sediments are connected and interlinked by hydrological phase and these are functionally similar and share a number of common features Fig. 18.3 Soils and sediments are connected and interlinked by hydrological phase and these are...

Heavy Metal Detoxification and Tolerance in Higher Plants

Potential cellular mechanisms for metal detoxification and tolerance in higher plants are summarized as 1 restriction of metal movement to roots by mycorrhizas, 2 binding to cell wall and root exudates, 3 reduced influx across plasma membrane, 4 active efflux into apoplast, 5 chelation in cytosol by various ligands, 6 repair and protection of plasma membrane under stress conditions, and 7 transport of and accumulation of metals in vacuole Hall 2002 . Hyperaccumulator or accumulator plants and...

Sugar Beet

Salinity is a limiting factor to crop production. Yields of most crops are decreased when cultivated in salt-affected areas. Generally, salinity problems are handled by chemical and biological methods. Chemical methods are usually used to reclaim sodic soils. While cultivation of salt-tolerant species on salt-affected lands forms the basis of the biological reclamation, identification of a wide variety of species with higher salt tolerance is important to achieve more success from this...

Biofilm and Biosorption

Biofilms are assemblages of single or multiple populations that are attached to biotic or abiotic surfaces through extracellular polymeric substances (Singh et al. 2006). They are less susceptible to metal toxicity than planktonic cell population (Harrison et al. 2005 Davies et al. 2007) which open new perspectives for biofilmmediated bioremediation processes (Singh et al. 2006 Harrison et al 2007 Diels et al. 2003 Chang et al. 2006). Haack and Warren (2003) studied microbial biofilms metal...

Physiological Effects and Toxicity

Pentavalent Transition State

The total body pool of vanadium is low depending on the source of information, it varies between ca. 0.1 and 1 mg (Wenning and Kirsch 1988 Leonard and Gerber 1994), corresponding to an approximate concentration of c 0.03-0.3 pM. The average vanadium concentration in blood is 2.3 pg L1 (c 45 nM) (Leuschner et al. 1994). Vanadium contents in food are typically around 30 pg V kg1 food (Wenning and Kirsch 1988), while drinking water commonly contains less than 10 pg L1 (c < 0.2 pM) (Cohen 1996)....

Promoted Zeolite Synthesis in Soil

In order to promote both metal precipitation and zeolite synthesis in soil, an alkaline pH is needed. Therefore, alkalizing agents such as NaOH, KOH, and lime must be added to soil. In addition, for zeolite synthesis, its constituting building blocks (PBU) are required, i.e., Si and Al containing framework tetrahedra (Fig. 22.1). These building blocks can be potentially provided by several Si- and Al-containing materials as reported in Sect. 22.1.1 and, in principle, by several soil...

Action of Cu0 Nanoparticles on Plants

As is seen from the material presented in the previous division (Sect. 8.5.1), metal ions, Cu in particular, may be reduced to the metallic form in the living plant (Haverkamp and Marshall 2009), although the extent of this process is rather limited. In contrast, natural and engineered sources of NPs are rather sizeable among the natural sources, volcanoes are of importance. As to the production of engineered nanoparticles (ENPs), according to the evidence from The Royal Society and Royal...

Sulfite Reductase

SiR is the last enzyme in the pathway of reduction from sulfate to sulfide. It is constitutively expressed and is not subject to allosteric effectors or posttranslational modification (Nakayama et al. 2000). Although its role in control of flux through the pathway has sometimes been neglected, it has been shown that decreasing its activity creates a bottleneck effect for the entire reductive pathway and downstream metabolites (Khan et al. 2010). In Arabidopsis thaliana, SiR is encoded by the...

Plant Uptake of Metals

The factors affecting the amounts of metal absorbed by a plant are those controlling (a) the concentration and speciation of the metal in the soil solution, (b) the movement of the metal from the bulk soil to the root surface, (c) the transport of the metal from the root surface in the root, and (d) its translocation from the root to the shoot (Peterson and Alloway 1979). Plant uptake of mobile ions present in the soil solution is largely determined by the total quantity of this ion in the...

Soil Properties

The physical and chemical characteristics of soils (i.e., texture, depth, pH, and organic matter) affect earthworm activity significantly. These characteristics are largely influenced by climatic factors (i.e., precipitation and temperature). For example, basic cations such as Na+, Mg2+, and Ca2+ are leached through the soil profile, replaced with H+ and eventually results in soil acidification in regions with heavy rainfall. Earthworm activity declines rapidly below pH 4.5 and most species...

Earthworm Castings

Earthworms usually can digest soil or organic materials at the rate of 60 of their body mass and defecate their fecal pellets which are called earthworm castings into their burrows in soil. There are basically four types of earthworm castings (Lee 1985 Lavelle 1988 Edwards and Bohlen 1996). The first type is globular and usually produced by large earthworm species i.e., anecics and endogeics. Second type is also formed by endogeics and anecics but it is usually shapeless. Third, these species...

Earthworm Effects on Soil Characteristics

The influences of earthworms on soil characteristics are mainly driven by their feeding, casting, and burrowing activities (Lavelle and Spain 2001). Depending on the mineral soil and or organic material digested by earthworms, their casts accumulated at soil surface are rich in organic compounds and may change soil properties. Organic constituents in earthworm castings are readily mineralized due to their high C, N, and water contents (Kizilkaya 2008) and this increases stabile aggregate...

Conclusion

In conclusion, the As tolerance and detoxification mechanisms may be summarized in a sequential flow as follows (1) Restrict As inflow at very first stage from medium to the roots, whatever amount of As enters the roots. (2) Efflux the most of this accumulated As back to the medium, whatever of As remains in root cells. (3) Restrict translocation of the metalloid from root to shoot through its complexa-tion and sequestration in vacuoles, either complexing it there with GSH and PCs or...

Heavy Metals Content in Sugar Crops 2041 Sugar Cane

Roots, stems, and leaves of sugar cane (Saccharum spp.) were collected in 25 points of an area under direct influence of the municipal landfill site (MLS) and medical waste treatment system (MWTS) of Ribeirao Preto, Sao Paulo, Brazil (Segura-Munoz et al. 2006). The roots contained Cd, 0.22 0.12 Cr, 64.3 48.7 Cu, 140.6 27.7 Hg, 0.04 0.02 Mn, 561.6 283.3 Pb, 7.9 2.1 and Zn, 177.4 64.9 mg kg-1 dry weight. Metal levels in stems were 80-90 of those found in roots, while the concentrations detected...

Mechanisms of Tolerance to Metals in Aquatic Macrophytes

As sessile organisms, plants must deal with environmental limitations to survive. Plants growing in metal-polluted habitats have developed complex mechanisms to tolerate elevated concentrations of metals and to control cell homeostasis in potentially harmful environment. In the case of wetland plants, metal tolerance is particularly important as they are usually exposed to both overlying water and or sediment and they take up nutrients and other minerals from both environments (Hinman and...

Role of Macrophytes in Trace Metal Dynamics in Wetland Sediments

The influence of aquatic plants and their metabolism may alter the distribution of trace metals between the solid and aqueous phases. There is little knowledge on how the combined defects of wetland plants influence the biogeochemistry of wetland sediments and thereby the trace metal dynamics (Namiesnik and Rabajczyk 2010). To survive in water-saturated sediments, aquatic macrophytes have developed specialized adaptations. To support root respiration under anoxic conditions, they can...

Binding of CdII to Activate PCS

Although Cd(II) is essential for PCS-mediated PC synthesis to proceed, the role of Cd(II) in the reaction is equivocal. One of the possible mechanisms is that Cd(II) is solely required to form the substrate Cd(II)-GSH2 complex in which the enzyme is already in an active form without Cd(II) binding, while another mechanism is that the enzyme needs to bind Cd(II) for activation. The evidence supporting the latter notion was obtained from a PCS assay at a constant total Cd(II) concentration (Fig....

Overview of Sulfur Metabolism

In plants, the reductive sulfate assimilation pathway consists of two phases the reduction of sulfate to sulfide and the assimilation of sulfide into cysteine (Fig. 15.1). These phases also occur in distinct organelles. Sulfate reduction takes place in the plastids with cysteine synthesis occurring in the plastids as well as in the mitochondria and cytosol (Wu et al. 2010). After uptake from the environment, sulfate is first activated by the enzyme ATP sulfurylase (ATPS) via conversion of ATP...

Salinity and Cadmium Speciation

Cd2+ is the predominant ionic species in soil solution, while it can form ionic complexes such as CdCl+, CdOH+, CdHCO3+, CdCl3, CdCl42 Cd(OH)3 and Cd (OH)42 as well as complexes with organic substances. Studies have shown that chloride-induced salinity, mainly NaCl, increased Cd concentration in cultivated plants (McLaughlin et al. 1994 Weggler-Beaton et al. 2000 Muhling and Lauchli 2003). In a large-scale study, on wheat fields of northeastern North Dakota, Norvell et al. (2000) found that...

Bioaugmentation and Biostimulation

Bioaugmentation is a process in which efficient metal microbial species are added into soil or reactor to remediate the system. Bioaugmentation is the process of introducing metal-immobilizing population or a population which transforms metal into less toxic state into the site. Biostimulation is the process by which a stimulus to the microorganisms that already exist in the site is provided by adding nutrients and other growth substrates, together with electron donors and acceptors....

Apoplast Involvement in Copper Detoxification

Copper penetrates into the plant mainly as a bivalent cation Cu2+, although it was reported that sometimes it is reduced near the root surface and penetrates into the root cells as a monovalent cation (Kr mer and Clemens 2006 Cohu and Pilon 2010) or even as a free metal (see Sect. 8.5.2). Since the cell wall is a negatively charged ion exchanger, it is quite clear that a part of Cu ions is absorbed by the cell wall on the path of their movement into the cell. Moreover, an additional copper...

Soil and Vegetation Sampling and Analytical Methods

The soil samplings were carried out previously to the application of amendments (time 0), and at 6 months, 1, 2, and 5 years after application of amendments. Composite soil samples from five sub-samples were taken from the 0-15 cm layer for each treatment plot. Samples were air-dried for 7 days, passed through a 2-mm sieve and stored at room temperature prior to laboratory analyses. Although the vegetation in the tailing pond of study was absent, the application of amendments in the plots...

Contributors

Sustainable Use, Management, and Reclamation of Soil and Water Research Group. Department of Agrarian Science and Technology, Technical University of Cartagena, Paseo Alfonso XIII, 52, 30203 Cartagena, Murcia, Spain Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, j.a.acostaa viles uva.nl Agrawal, Jyoti Amity Institute of Microbial Technology, Amity University Uttar Pradesh, Block 'E 3'...