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Trees Are Capable of Taking in Heavy Metals

Jul 11, 2019

Trees Are Capable of Taking in Heavy Metals

The advent of human civilization which has seen astounding advancements in all spheres of life has brought up climate ruination through pollution. Pollution ensues with every human desire to better their life at the expense of the environment. The growing deterioration of the environment now necessitates appropriate mitigation measures such as the circular technology and green economies.

Upon this realization, human beings have started adopting pollution mitigation strategies and making attempts in tree planting. Trees arguably take up the Carbon Dioxide released during pollution and converts it into safe physical solid state that does not escalate the global temperatures. Historians predispose that necessity is the genesis of invention and that is better understood with the rare discovery of the additional role of trees in the ecosystem.

Heavy Metals in the Food Chain

Pollution is further caused by irresponsible disposal of waste products. Waste products can be classified as either organic (that which rots) and inorganic (does not rot). Among the inorganic waste are the virulent heavy metals. These are within the human neighborhood for their extensive and nobble applications in energy, automotive and construction industry. Despite their necessary use, some of these metals are heavy and ostensibly noxious.

Heavy metals are chemical elements with a relatively high density. They are normally toxic at low concentrations. They occur naturally in the crust of the earth. They include Lead, Chromium, Arsenic, Zinc, Cadmium, Copper, Mercury and Nickel.  Human beings, being a littering species, have increased the amount of these heavy metals in the environment through anthropogenic activities.

Sources of contamination like exhaust gases, energy and fuel production, municipal sludge, synthetic fertilizers and industrial effluent have been rampant. The metals find their way into the soil where they are stored. They rarely degrade; They persist in the environment for long durations of time thus rendering them environmental contaminants with severe threat to humans and the ecosystem.

Humans get into contact with the metals through consuming contaminated water, breathing in air within emission sources and consuming them through the food chain. In agriculture contaminated soils reduce the food quality and limit land use. In human beings, they accumulate in the soft tissue inhibiting growth, suppressing oxygen consumption, impairing reproduction and impairing tissue repair.

Reducing Heavy Metals Using Trees

Several methods have been used to get rid of metals in the surrounding systems. They include precipitation, adsorption, bio-sorption, ion exchange, filtration, coagulation and cementation. Such heavy metal remediation technologies are however expensive and rare in some of the countries. They are also time consuming and have been considered destructive. They may only be relatively effective when handling a large amount of hazardous waste. In the long run, these conventional strategies end up polluting the environment.

Fortunately, scientists have stumbled upon unusual type of trees that can absorb large amounts of metal compounds. Known as hyperaccumulators, they are arousing interest as useful cleaners of polluted soils and water bodies. Plants are transplanted into metal polluted areas, where they accumulate the metals in their roots and shoots.  

After the plant has become of size and accumulated enough metal, the upper parts are harvested resulting to permanent removal of the metals from the soil. This plant-based technology can be used to clean aquatic environments, stabilize soils, extracting and releasing inorganic compounds into the atmosphere and/or harvesting the plants parts with high metal concentrations for metal recovery. This is known as phytoremediation. It offers a sustainable development approach in environmental restoration. It is a competitive technology that is superior to existing ones and worth further exploration and adoption.

By Arnold Muthanga

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