Consequences And Effects Of The Natural Geochemical Cycles Of Heavy Metals
Abstract:
Soil serves as one of the basic medium of life as a variety of elements, which are vital to life are embedded in it. However, the human activities are polluting the soil unintentionally. Consequently, a wide range of contaminants enter the soil. Nevertheless, heavy metals are the most toxic of all the pollutants. Among these, lead, cadmium, chromium, mercury and arsenic are most toxic and can cause multiple organ damages even when present in small amount. Although, these elements are necessary for soil animals as well as plants in extremely low quantities. However, anthropogenic activities like mining, smelting, fuel burning etc have disturbed the natural geochemical cycles of heavy metals which raises concern over their management …show more content…
But some are playing havoc to every life form while the others have negligible effects. Among these, heavy metals are the contaminants which are harmful even when present in traces (Irma et al., 2013; Jayanthi et al., 2016).
Heavy metals are the most toxic of the all inorganic pollutants present in soil. These may either be present naturally or injected through human activities. The soil properties including pH, soil organic matter and clay content determine the bioavailability of heavy metals in soil (Annu et al., 2016).
U.S Environmental Protection Agency and International Agency for Research on Cancer declared certain heavy metals including Pb, Cd, Hg, As and Cr as most toxic of all the pollutants and termed them carcinogens due to their potential harms to human health (Tchounwou et al., 2014).
Subsequently, it is the need of hour to develop useful techniques to get rid of these toxic heavy metals. Among these, Bioremediation is one of the most familiar and reliable method for degradation and elimination of heavy metals. Bioremediation involves variety of living organisms including bacteria, fungi and algae for the removal and degradation of these contaminants from the environment (Li et al., …show more content…
Rhodobacter sphaeroids is a photosynthetic, gram-positive bacterium and it has been used extensively to treat soil contaminated with various pollutant types including heavy metals such as Cd and Pb due to its resistance to different factors that affect bacterial growth and activity. These factors include carbon starvation, herbicides, varied amounts of salt, organic matter and heavy metals. R. sphaeroids minimizes the effects of lead and cadmium by reducing their bioavailability to plants (Li et al., 2016).
The phylum Actinobacteria includes facultative, gram positive anaerobic microorganisms which have the ability to stabilize or transform Cd, Cr, As, Hg and pb to less toxic forms, thus making them less bioavailable to plants (Alvarez et al., 2016).
Streptomyces strains and heavy metal
Soil serves as one of the basic medium of life as a variety of elements, which are vital to life are embedded in it. However, the human activities are polluting the soil unintentionally. Consequently, a wide range of contaminants enter the soil. Nevertheless, heavy metals are the most toxic of all the pollutants. Among these, lead, cadmium, chromium, mercury and arsenic are most toxic and can cause multiple organ damages even when present in small amount. Although, these elements are necessary for soil animals as well as plants in extremely low quantities. However, anthropogenic activities like mining, smelting, fuel burning etc have disturbed the natural geochemical cycles of heavy metals which raises concern over their management …show more content…
But some are playing havoc to every life form while the others have negligible effects. Among these, heavy metals are the contaminants which are harmful even when present in traces (Irma et al., 2013; Jayanthi et al., 2016).
Heavy metals are the most toxic of the all inorganic pollutants present in soil. These may either be present naturally or injected through human activities. The soil properties including pH, soil organic matter and clay content determine the bioavailability of heavy metals in soil (Annu et al., 2016).
U.S Environmental Protection Agency and International Agency for Research on Cancer declared certain heavy metals including Pb, Cd, Hg, As and Cr as most toxic of all the pollutants and termed them carcinogens due to their potential harms to human health (Tchounwou et al., 2014).
Subsequently, it is the need of hour to develop useful techniques to get rid of these toxic heavy metals. Among these, Bioremediation is one of the most familiar and reliable method for degradation and elimination of heavy metals. Bioremediation involves variety of living organisms including bacteria, fungi and algae for the removal and degradation of these contaminants from the environment (Li et al., …show more content…
Rhodobacter sphaeroids is a photosynthetic, gram-positive bacterium and it has been used extensively to treat soil contaminated with various pollutant types including heavy metals such as Cd and Pb due to its resistance to different factors that affect bacterial growth and activity. These factors include carbon starvation, herbicides, varied amounts of salt, organic matter and heavy metals. R. sphaeroids minimizes the effects of lead and cadmium by reducing their bioavailability to plants (Li et al., 2016).
The phylum Actinobacteria includes facultative, gram positive anaerobic microorganisms which have the ability to stabilize or transform Cd, Cr, As, Hg and pb to less toxic forms, thus making them less bioavailable to plants (Alvarez et al., 2016).
Streptomyces strains and heavy metal