A heavy metal is a member of an ill-defined subset of elements that exhibit metallic properties, which would mainly include the transition metals, some metalloids, lanthanides, and actinides. Many different definitions have been proposed -- some based on density, some on atomic number or atomic weight, and some on chemical properties or toxicity. The term heavy metal has been called "meaningless and misleading" in a IUPAC technical report due to the contradictory definitions and its lack of a "coherent scientific basis".[1] As discussed below, depending on context, heavy metal can include elements lighter than carbon and can exclude some of the heaviest metals. One source defines "heavy metal" as "... common transition metals, such as copper, lead, and zinc. These metals are a cause of environmental pollution (heavy-metal pollution) from a number of sources, including lead in petrol, industrial effluents, and leaching of metal ions from the soil into lakes and rivers by acid rain.
A heavy metal is a member of an ill-defined subset of elements that exhibit metallic properties, which would mainly include the transition metals, some metalloids, lanthanides, and actinides.
Heavy metal pollution represents a global challenge to both public health and environmental sustainability. Any means to reduce heavy metal pollution in the environment is of considerable economic significance. The use of green plants to clean up heavy metal pollution is an environmentally friendly as well as a low-cost approach to the problem. This plant-based biotechnology is commonly known as ‘phytoremediation’. Presently, there is limited application of this technology because useful plants with enhanced heavy metal resistance/tolerance are still needed to assist remediation of environments polluted with heavy metals. A key to improved phytoremediation of heavy metal pollution lies in research seeking for a better understanding of the mechanism(s) of heavy metal resistance/tolerance in plants. This E-book presents a unique treatment of the topics that have never been comprehensively brought together before in a single advanced reference. The volume explores aspects of plant biology that are critical for employing phytoremedation techniques to combat heavy metal contamination such as the specific plant biology, seed biology, plant tissue culture and enzymology. This E-book will be a useful reference to plant biologists, biotechnologists and environmental engineers seeking information about phytoremediation of heavy metals from the environment.
Recent Advances Towards Improved Phytoremediation of Heavy Metal Pollution,
2013, 55-67 55 Effect of Nitric Oxide Donors on Metal Toxicity in Plants David
W.M. Leung* School of Biological Sciences, University of Canterbury, Private Bag
...
Industrialisation and urbanisation have led to the rapid deterioration in the water quality of rivers, lakes and reservoirs. Heavy metal pollution in aquatic ecosystems has become the most important point for discussion in recent years. The problem of heavy metal pollution is emerging as a matter of concern at local, regional and also at global scales. Heavy metal pollution in aquatic ecosystems pose serious threats to aquatic biodiversity, and drinking of contaminated water pose severe health hazards in humans. Therefore, the focus of attention has been shifted from mere monitoring of environmental conditions to the development of alternative means to solve the environmental problems at local and global levels. This new book discusses how economic aspects and side effects of conventional treatment technologies in aquatic ecosystems paved way to phytoremediation technology.
This new book discusses how economic aspects and side effects of conventional treatment technologies in aquatic ecosystems paved way to phytoremediation technology.
Trace metals occur as natural constituents of the earth's crust, and are ever present constituents of soils, natural waters and living matter. The biological significance of this disparate assemblage of elements has gradually been uncovered during the twentieth century; the resultant picture is one of ever-increasing complexity. Several of these elements have been demonstrated to be essential to the functions of living organisms, others appear to only interact with living matter in a toxic manner, whilst an ever-decreasing number do not fall conveniently into either category. When the interactions between trace metals and plants are considered, one must take full account of the known chemical properties of each element. Consideration must be given to differences in chemical reactivity, solubility and to interactions with other inorganic and organic molecules. A clear understanding of the basic chemical properties of an element of interest is an essential pre-requisite to any subsequent consideration of its biological significance. Due consideration to basic chemical considerations is a theme which runs through the collection of chapters in both volumes.
Due consideration to basic chemical considerations is a theme which runs through the collection of chapters in both volumes.
In the past two decades there has been an increasing public awareness of the hazards that exist from the contamination of the environment by toxic substances. 'Heavy metals' and the terrestrial environment are but one facet of the impact of toxic substances on the natural environment, and the use of biological materials for indicating the occurrence of, and continually monitoring the presence of, these materials is a specific topic which is of considerable interest to a diverse range of individuals, organisations and disciplines. It was our intention when we first en visaged this book that it should contain a description of a range of circumstances in which biological monitoring techniques have been employed in the terrestrial environment and that it should be seen as a practical text which dealt with the merits, shortcomings and suitability of biological monitoring materials. Monitoring is, however, a manifold process. It serves not only to provide information on past and present concentrations of toxic materials in various components of the environ ment, but also to provide information on the processes of environmental release, transport, accumulation and toxicity. Indeed, this may be one of the greatest virtues of biological monitoring over other forms of monitor ing. According to the skill of the staff employed in the monitoring procedure, the information that is accrued can have a vastly different value.
It was our intention when we first en visaged this book that it should contain a description of a range of circumstances in which biological monitoring techniques have been employed in the terrestrial environment and that it should be seen ...
This book has up-to-date literature and research findings on the heavy metals such as, mercury, cobalt, cadmium, managnese, copper, chromium, boron, iron, lead, nickel, selenium, vanadium, zinc, arsenic, silver, gold, etc. The author have discussed their histopathological, biochemical, histochemical and enzymological effects in plants and animals, particularly in liver, kidney, heart, muscles, brain, bones, reproductive organs, intestine, endocrine system, etc.
ShakirAH and Mohammad Athar Introduction Metal ions are of particular interest
to biochemists, as many of them play key roles in various biochemical reactions
taking place in the body of an organism. They form the essential component of ...
Heavy metals can be emitted into environment by both natural and anthropogenic sources, mainly mining and industrial activity. Human exposure occurs through all environmental media. Infants are more susceptible to the adverse effects of exposure. Increasing attention is now being paid to the mental development of children exposed to heavy metals. The purpose of this book is to evaluate the existing knowledge on intellectual impairment in children exposed to heavy metals in their living environment and to identify the research needs in order to obtain a clearer picture of the situation in countries and regions at risk, in which the economy is closely related to metallurgy and heavy metals emission, and to recommend a strategy for human protection. In greater detail the main objectives could be formulated as follows: to review the principal sources of single, and complex mixtures of, heavy metal pollutants in the environment; to identify suitable methodology for chemical analyses in the environment and in humans; to evaluate the existing methods for measuring mental impairment, including their reliability and validity; to recommend a standard testing protocol to be used in future research; to assess the future role of environmental heavy metal pollution in countries and regions at risk and its effects on children’s neurological development; to recommend a prevention strategy for protecting children’s health and development.
The purpose of this book is to evaluate the existing knowledge on intellectual impairment in children exposed to heavy metals in their living environment and to identify the research needs in order to obtain a clearer picture of the ...
