Potentially toxic trace element analysis

Sediment Analysis. Sediment is the most chemically and biologically active component of the aquatic environment. Benthic invertebrate and microbial life concentrate in the sediment, a natural sink for precipitated metal forms, and an excellent sorbent for many metal species. TTie extent to which potentially toxic trace element forms bind to sediment is determined by the sediment s binding intensity and capacity and various solution parameters, as well as the concentration and nature of the metal forms of interest. Under some conditions sediment analyses can readily indicate sources of discharged trace elements. 

Well over 10,000 papers dealing with activation analysis have appeared in the literature. Most of these (99%) have been published since 1955. Some of the more interesting applications have been determining potentially toxic trace elements in natural waters and environmental samples, authenticating paintings and other objects of art, and studying impurities in semiconductor materials, trace elements in plant and animal metabolism, and trace-element abundances in terrestrial rocks, meteorites, and lunar samples. In the analyses of lunar samples, more than twice as many trace-element determinations have been reported by activation analysis than by any other technique. In fact, the activation-analysis determinations on these rare samples probably exceed those by all other techniques combined. 

Chemical elements that are either present naturally in the soil or introduced by pollution are more usefully estimated in terms of availability of the element, because this property can be related to mobility and uptake by plants. A good estimation of availability can be achieved by measuring the concentration of the element in soil pore water. Recent achievements in analytical techniques allowed to expand the range of interest to trace elements, which play a crucial role both in contaminated and uncontaminated soils and include those defined as potentially toxic elements (PTE) in environmental studies. A complete chemical analysis of soil pore water represents a powerful diagnostic tool for the interpretation of many soil chemical phenomena relating to soil fertility, mineralogy and environmental fate. This chapter describes some of the current methodologies... 

It is possible to map the toxicity potential areas of trace elements by obtaining classification models based on national-scale data synthesis programs. To obtain reliable analytical information, "the main methods of structural analysis may be coupled two-by-two from the point of view of correlating various sources of information"1 (Figure 6.1). 

The potentials of using activation analysis techniques for studies in botany and plant biochemistry are good. It offers a practical method to investigate and measure (a) the concentrations of trace elements, (b) the behavior of essential trace elements, (c) the nutritional rates and metabolic functions of the absorption of trace elements from soils, (d) the determination of toxic elements in plants and soils, and (e) the origin of specific flora and their relation to similar flora from other geographical regions. 

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