Title : Biogeochemistry of new potential toxic trace elements
Abstract:
Up to now, information about biogeochemistry of many trace elements is scarce. It is commonly accepted that only a small part of the so-called biologically essential elements are needed for normal plant development. Since the last century, another group of elements (they are called heavy metals) has attracted considerable interest. Over the past decades, a great body of experimental material on environmental chemistry of the elements has been collected. On the other hand, the biogeochemistry of many other elements has not yet attracted much attention. Meanwhile, all elements known to date are always present in soil and plants. It can be assumed that those trace elements that have so far received little attention of researchers also play a certain role in biogeochemical processes. Contrary to the generally recognized opinion, it may be assumed that all elements are involved in the biogeochemical processes. It can be stated that our knowledge of biological role of one or another element is still in its infancy. This especially concerns trace elements that usually present in the environment at low concentrations. An insufficient quality of analytical techniques that are applied for elemental analysis is probably one of the reasons why information about significance or toxicity of the elements is still limited. With development of new methods of analysis, the information on biogeochemistry of previously poorly-studied ultratrace elements will undoubtedly grow.
For our research, several trace elements that are not so widely present in scientific reports were selected. In the experiments, widely grown crops as well as wild plants were studied. The plants were grown in the soils that differed in the main parameters (texture, pH, concentrations of exchangeable cations) and also in the level of contamination. The main aim of the research was to study the ability of the plants to accumulate both well-known toxic elements and also the trace elements that are poorly-studied yet.
The experimental results showed that the plants were capable of accumulating various elements. The uptake of the elements depended on type of soil, level of soil contamination and was often different for different plant species. The plants were capable of uptaking different amounts of one or another element even though they grew under the same conditions. It can be concluded that many trace elements that occur in the environment at low concentrations and have not got yet a proper examination should also be considered as potentially toxic elements. The improvement of accuracy and sensitivity of analytical techniques used for elemental analysis of plant and soil material can help to get a new insight into the significance and/or potential toxicity of many new trace and ultratrace elements.
