Trace element analyses of skeletal remains and associated soils from the Tutu site

Since the 1970s, anthropologists have employed trace element analyses of skeletal materials as a means of evaluating dietary intakes and some nutritional disorders of past peoples (for reviews, see Sandford, 1992, 1993b). Historically, efforts to use elemental analyses in this manner were concentrated along three lines. The first approach involves the use of strontium (Sr) and strontium/calcium ratios (Sr/Ca) to assess the relative dietary importance of plant resources and animal protein. In the most general terms, this strategy is based on the premise that organisms take up Sr in amounts that vary inversely to their position on the food chain such that plants tend to have higher Sr concentrations than animal species. A second paleodietary application of elemental analyses, the so-called multi-element approach, uses a much larger group of elements to make inferences about the relative importance of plant and animal constituents in the diet. Following this reasoning, the concentrations of elements such as zinc (Zn) and copper (Cu) which tend to be higher in animal food sources are contrasted to levels of such elements as magnesium (Mg) that are higher in plants. Finally, a third technique employs analyses of a single element to address questions relating to both diet and disease. Thus, elements such as iron have been studied to shed light on the hypothesized occurrence of iron deficiency anemia in past populations (Sandford, Van Gerven & Maglen, 1983), while analyses for the element lead (Pb) have been used to investigate possible past instances of lead ingestion and/or intoxication (Aufderheide, Whitmers, Rapp & Wallgren, 1988).