An introduction to the heavy metals and their uptake by plants

Phytoextraction is considered as an environmentaly friendly method to remove metals from contaminated soils in situ. It is the most ecological cleanup technology for contaminated soils and is also known as a green technology.

Remediation with plants requires that contaminants be in contact with the root zone of the plants. The most common trivalent inorganic arsenic compounds are arsenic trioxide, sodium arsenite, and arsenic trichloride [ 13 ]. According to Sinha et al. The major effects of mercury poisoning manifest as neurological and renal disturbances as it can easily pass the blood-brain barrier and has effect on the brain [ 26 ].

Plants generally do not accumulate trace elements beyond near-term metabolic needs. Phytoremediation as possibly the cleanest and cheapest technology can be employed in the remediation of selected hazardous sites [ 29 ].

Conclusions Heavy metals uptake, by plants using phytoremediation technology, seems to be a prosperous way to remediate heavy-metals-contaminated environment. Therefore, for sites that pose acute risks for human and other ecological receptors, phytoremediation may not be the remediation technique of choice [ 2946 ].

Plants also perform an important secondary role in physically stabilizing the soil with their root system, preventing erosion, protecting the soil surface, and reducing the impact of rain.

Introduction Heavy metals are released into the environment by both natural and anthropogenic sources. It is applicable to a wide range of toxic metals and radionuclides [ 32 ] and also useful for treating a broad range of environmental contaminants, including organic and inorganic contaminants [ 46 ].

Factors Affecting the Uptake Mechanisms There are several factors which can affect the uptake mechanism of heavy metals, as shown in Figure 3. There are three soluble forms of Hg in the soil environment.

Soil can be contaminated with Pb from several other sources such as industrial sites, from leaded fuels, old lead plumbing pipes, or even old orchard sites in production where lead arsenate is used.

Table 1 Additional information extracted from selected studies to evaluate the effect of aquatic plants on adsorption of Cu, Zn, and Cd.

Previous article in issue. Soil washing for removing contaminated soil is an alternative way to excavation and disposal to landfill.

Inorganic arsenic compounds are mainly used to preserve wood. Methodology Surface soil samples cm depth were taken by hand auger 2. Addition of Chelating Agent The increase of the uptake of heavy metals by the energy crops can be influenced by increasing the bioavailability of heavy metals through addition of biodegradable physicochemical factors such as chelating agents, and micronutrients, and also by stimulating the heavy-metal-uptake capacity of the microbial community in and around the plant.

Phytostabilisation Phytostabilisation is the use of certain plant species to immobilize the contaminants in the soil and groundwater through absorption and accumulation in plant tissues, adsorption onto roots, or precipitation within the root zone preventing their migration in soil, as well as their movement by erosion and deflation [ 2839 — 42 ].

Understanding mass balance analyses and the metabolic fate of pollutants in plants are the keys to proving the applicability of phytoremediation [ 46 ]. Metal concentrations in plants were also estimated by computer-aided statistical methods.

Toxic heavy metal

Harvested plant biomass from phytoextraction may be classified as a hazardous waste, hence, disposal should be proper. Beside the natural activities, almost all human activities also have potential contribution to produce heavy metals as side effects.

The use of metal-accumulating bioenergy crops might be suitable for this purpose. The uptake of a compound is affected by plant species characteristic [ 44 ]. Phytoremediation is a low-cost option and inexpensive approach for remediating environmental media, particularly suited to large sites that have relatively low levels of contamination [ 34 ].

International Journal of Chemical Engineering

Chelates are not without side effects and can also remove beneficial metals from the body. These elements were selected because they are well-established as being toxic for living systems and their effects in humans have been widely documented. This is for metals, metalloids, radionuclides, nonmetals, and organics contaminants in soils, sediments, and sludges medium [ 2931 ].

In the 2nd century BC the Greek botanist Nicander described the colic and paralysis seen in lead-poisoned people. This process, termed evapotranspiration, is responsible for moving contamination into the plant shoots as well.

This phytotoxicity could lead to a remedial approach in which high-concentration waste is handled with expensive ex situ techniques that quickly reduce acute risk, while in situ phytoremediation is used over a longer period of time to clean the high volumes of lower contaminant concentrations [ 29 ].

The excluders restrict contaminant uptake into their biomass. These all are called as phytostabilization process. View at Google Scholar E.3 1. Introduction Heavy metals and plants – a complex relationship Many heavy metals such as Cu, Ni and Zn are well-known as essential trace elements.

While accumulated metal ions are detoxified by phytochelatins, which are synthesized from glutathione in plants during their exposure to heavy metals. Phytochelatins form complex with metal ions and sequestered them into the vacuole. This mechanism of heavy metal tolerance in plants has strongly suggested that glutathione should not be.

the heavy metal uptake inside the shoot plays at least as important a role in hyperaccumulation as do the root mechanism s.

Clearly, the major ligands for both Cd and Zn in hyperaccumulator plants.

Plants will affect the soil through their ability to lower the pH and oxygenate the sediment, which affects the availability of the metals, increasing the bioavailability of heavy metals by the addition of biodegradable physicochemical factors, such as.

Apr 04,  · Heavy metals in plants and factors affecting metal uptake by plants It is well known that concentrations of Cd in edible vegetables range from to μg g −1 (DW: dry weight) and leafy plants such as lettuce, cabbage, spinach contain relatively higher Cd than grain or fruit plants such as apple, barley, corn, oat and rice [ 20 ].

There is evidence that plants can accumulate heavy metals in their tissues such as Sebera acuminate and Thlaspi caerulescens (Cunningham and Ow ), Arabidopsis thaliana (Delhaize ), Typha latifolia, and Phragmites australis (Ye et al.


An introduction to the heavy metals and their uptake by plants
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