Trace elements, health considerations

The objectives of studies of ambient and workplace air differ considerably. Ambient studies have been carried out to provide general knowledge, observe differences between locations, relate trace-element concentrations to sources, and seek correlations to other air pollution indices or to human health studies. Workplace measurements, on the other hand, are made to assure control of toxic materials at concentrations safe for the workers, as well as to seek better data on health effects. In the United States acceptable... 

The role of Cu as an essential trace element has focused attention on possible roles for copper chelation of biologically active ligands, with subsequent interference of normal transport and distribution, as well as the role of the metal in redox reactions due to the accessible oxidation states of (I) and (II). Similarly, the physiological response of copper levels in disease conditions [50] and the overall role of trace metals in health and disease [51, 52] are relevant and of considerable importance. The increase in serum copper content in infections, arthritic diseases, and certain neoplasms is well documented and, in fact, the subsequent decrease in level upon treatment has been used successfully as an indicator of cancer remission [50]. Copper complexes may be effective in therapy due in part to their ability to mimic this physiological response of elevated copper [53] and, clearly, the interplay of introduced copper with pre-existent bound copper and effects on copper—protein mediated processes will affect the ultimate biological fate of the complex. Likewise, while the excess accumulation of free Cu, and indeed Fe and Zn, caused by malfunction or absence of normal metabolic pathways is extremely damaging to the body, the controlled release of such metals may be beneficially cytotoxic. The widespread pharmacological effects of copper complexes have been briefly reviewed [54]. 

To summarise our consideration of the consequences of the substantial contamination of soils which has already occurred, particularly in urban and industrial areas, we can conclude that a general enhancement of the levels of potentially toxic trace elements in plants grown in urban areas could lead to deleterious effects both on the plants and on the health of animals or humans eating them. The enhancement of trace-element levels in soils resulting from contamination can also have effects on biochemical processes occurring in the soil, and Tyler and co-workers [359] have reported increased nitrate accumulation in soil in which the cadmium and lead levels had been experimentally enhanced. 

The Use of Activation Analysis in Medicine.—The utilization of neutron activation techniques in medical and public health investigations has increased considerably in recent times. Reference was made earlier to the recent conferences devoted exclusively to applications in the investigation of environmental pollution and in the life sciences. The proceedings of the latter conference and the report of a panel meeting to discuss the uses of activation analysis in the study of mineral element metabolism give a good assessment of the current applications of activation techniques. Examples are the diagnosis of cystic fibrosis, the study of the role of trace elements in various diseases, and the measurement of iodine balance in man. The current in-... 

---