摘要:

Several elements, generally called trace elements, are present in natural waters at very low background concentration levels, as shown in Table 1. There is actually a consistent degree of arbitrariness in the definition of which elements should be considered as trace elements. In addition, several synonyms are used, mainly based on a concept of their concentration level (trace elements, ultratrace metals, trace inorganics) or their toxic effects (toxic metals, toxic elements, ecotoxic heavy metals). In the former case, once an operative definition of trace and ultratrace has been adopted, any difficulty would be overcome. In the latter case, an operative toxicity definition would seem to be more difficult to achieve because it depends too much on the type of toxicity considered (acute, chronic, lethal), on the type of biological species tested, and on the particular experimental conditions used, which might not be perfectly reproducible in different laboratories.

ISSN:0007-8980    

DOI:10.1080/10408348808542813

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A. Level-Crossing Phenomena and the Effect of Coherent Forward Scattering

ISSN:0007-8980    

DOI:10.1080/10408348808542814

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor