Relationship of trace elements and toxic elements in humans’ health

Elements which are detected in small but not precisely known amounts in the living body were called “trace elements” in the past. Recent advances in analytical technologies, such as the development of atomic absorption spectrometry, have made it possible to measure these elements precisely and to determine their functions and the characteristics of their deficiency and excess states. The so-called vitamin boom has passed, and it now appears to be boom-time for trace elements. Nowadays, cases with trace element deficiencies are often encountered clinically, especially during high-calorie parenteral therapy or enteral nutrition, and congenital abnormalities of trace element metabolism have been clarified successively. Thus, knowledge of the clinical aspects of trace elements is becoming indispensable for front-line clinicians. Meanwhile, epidemiological surveys and animal studies have suggested the possibility that some trace element deficiencies are associated with a reduced anti-oxidant potential in organisms (which is believed to possibly underlie the onset of cancer and atherosclerosis), accelerated aging, developmental retardation in children, and an increased incidence of abnormal pregnancies, immunological abnormalities, and lifestyle-related diseases.

 Thus, from the viewpoint of prophylactic medicine, study, survey, and prophylaxis of trace elements are also attracting close attention. Some Heavy metals have bio-importance as trace elements but the biotoxic effects of many of them in human biochemistry are of great concern. Hence, there is a need for proper understanding of mechanism involved, such as the concentrations and oxidation states, which make them harmful. It is also important to know their sources, leaching processes, chemical conversions and their modes of deposition in polluting the environment, which essentially supports life. Literature sources point to the fact that these metals are released into the environment by both natural and anthropogenic means, especially mining and industrial activities, and automobile exhausts. They leach into the underground waters, moving along water pathways and eventually depositing in the aquifer, or are washed away by run-off into surface waters thereby resulting in water and subsequently soil pollution. Poisoning and toxicity in ecosystem occur frequently through exchange and co-ordination mechanisms. When ingested, they form stable biotoxic compounds, thereby mutilating their structures and hindering bioreactions of their function.