10,326
edits
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→Biological classification of elements
Deficiency of these elements in the soil results in their low abundance in plants. Sequel to this, plants –as primary producers –would decline in supplying them to animals and humans– the consumers. Deficiency of these nutrients brings negative health effects to humans and animals. A typical example is iodine deficiency which leads to goiter, which is caused by ‘shortage’ of iodine in the rocks. On the other hand, over-abundance of any of these elements causes toxicity problems (Table 2). For instance, excess arsenic is known to cause lesion of the skin in some Asian countries such as Bangladesh and China (Bunnell et al, 2007).
Deficiency of these elements in the soil results in their low abundance in plants. Sequel to this, plants –as primary producers –would decline in supplying them to animals and humans– the consumers. Deficiency of these nutrients brings negative health effects to humans and animals. A typical example is iodine deficiency which leads to goiter, which is caused by ‘shortage’ of iodine in the rocks. On the other hand, over-abundance of any of these elements causes toxicity problems (Table 2). For instance, excess arsenic is known to cause lesion of the skin in some Asian countries such as Bangladesh and China (Bunnell et al, 2007).
{| class="wikitable"
|-
|+ Table 2: Diseases caused by the deficiencies and excessiveness/toxicity of some trace elements (after Khandare, 2012).
|-
! Element || Deficiency || Excessiveness/Toxicity
|-
| Iron || Anemia || Haemochromatosis
|-
| Copper ||Sway Back ||Chronic Copper Poisoning
|-
| Zinc || Dwarfism || Diarrhea
|-
| Cobalt || White Liver Disease || Heart Failure
|-
| Magnesium ||Convulsion, Malformation of the Skeleton ||Ataxia
|-
| Chromium ||Disturbances in Glucose Metabolism || Kidney Damage (Nephritis)
|-
| Selenium ||Liver Nechrosis || Hyperkeratosis
|}
However, some trace elements such as As, Cd, Pb, Hg and Rn have no/limited biological functions and are generally toxic to humans; they are called non-essential trace elements (Selinus et al, 2013).
However, some trace elements such as As, Cd, Pb, Hg and Rn have no/limited biological functions and are generally toxic to humans; they are called non-essential trace elements (Selinus et al, 2013).