ABSTRACT
Department of Environmental Science, University of Bradford, Bradford, West Yorkshire, BD7 1DP, England
ABSTRACT
Progress made in understanding trace metals in the environment is reviewed, especially over the last 30 years. The main focus is research in soils, plant uptake, and implications for human health. Until the 1960s the major concern was micronutrient research. Since then, the subject has broadened to encompass excess concentrations of both micronutrients and toxic trace metals. Despite a great increase in our understanding of these metals, there are still important questions unanswered. These include establishing a sound basis for sampling soils, sample treatment, and data handling. There is a need to establish back ground concentrations of trace metals locally, regionally, and nationally. Our understanding of the composition and dynamics of the soil solution is far from satisfactory, especially in terms of its role as a supplier of nutrient ions. Present models for predicting plant uptake from soils are too simple, and more complex models are needed. More generally, trace metal research is still dominated by *1
fact-finding, and insufficient emphasis is given to hypothesis testing and to predictive modeling. There is a lack of agreement on a rigorous definition of technical terms in common use. Although much is now known of the health effects of environmental levels of cadmium and lead, the more general impact of environmental concentrations of trace metals on health has been neglected.
