Lacustrine Archives of Metals from Mining and Other Industrial Activities—A Geochemical Approach

Abstract

Since the first studies reporting recent stratigraphic changes of metal concentration in lake sediments, many hundreds of studies have been published in the peer-reviewed literature. It is an impossible task to do justice to all of these works here; instead we: (1) examine recent methodological advances and place these in the context of the historical development of the discipline; and (2) explore the vari-ous purposes to which such methods have been applied. Such a historical emphasis may appear in conflict with the needs of a review of new approaches; however, this is not in fact the case for two main reasons. First, most new advances supplement rather than replace traditional methods, such that a thorough understanding of the practical and theoretical issues impacting these is still essential for reliable interpretation of palaeolimnological data. Second, while many of the new methods purport to circumvent problems, they achieve this only under favourable conditions, not dissimilar to the conditions that influence the earlier methods, so the same lesson must be learned anyway. Consequently, we use this historical narrative to address the fundamentals of the discipline. The chapter comprises two main parts; methodology and applications. The methodological section has three subsections: (1) Introduction to processes controlling natural variations in metal fluxes and concentrations in lake sediments; (2) Measurement of metal concentrations in sediments; (3) Calculation of enrichment or fluxes from sediment metal concentration data. There are four main applications subsections focusing on the value of lake sediment records of metals derived from mining or industry. They are: (1) Geochro-nological markers in sediments providing chronology for other research goals; (2) Lake sediment heavy metal records to quantify pollution loading histories, or to identify pollutant sources; (3) Identifying and quantifying pre-and post-mining baseline conditions; (4) Identifying pollutant pathways or environmental processes regulating heavy metals.