This is the report of the Dahlem Workshop held in Berlin during March 1983. In the introduction, the editor emphasizes the fact that millions of tons of heavy metals have been mined and are ultimately wasted in the biosphere. I. THORTON & P. ABRAHAMS collected historical records on metal pollution in the environment. Some sections of the report deal with aquatic environments. P. E. BUAT-MI~NARD describes the fluxes of metals through the atmosphere and oceans and calculates the atmospheric deposition in the ocean, its geographical variability and geochemical implications. M. BERNHARD & M. 0. ANDREAE describe the transport of trace metals in marine food chains, report the concentrations a t different trophic levels, and illustrate the means of transfer from marine foods to man. U. FORSTNER, in his section on terrestrial waters, remarks that the problem of metal pollution seems t o have passed its peak, partly as a result of recent improvements in wastewater treatment. He analyzes the mobilization of metals from sediments and describes their chemical speciation in freshwater systems. Other sections concern bacterial transformations, biochemical interactions and the hazard of specific metals, such as cadmium, mercury, and arsenic. There are group reports on changing biogeochemical cycles; on routes of transfer to humans; on bioavailability ; and on structure, mechanisms and toxicity. It was mentioned that major problems encountered in investigating the environmental cycling of toxic metals and estimating their intake by the human population is the quality of the available data and the serious difficulties in establishing any set of criteria for legislative action t o eliminate or control the metal pollution problem. Because most scientists work on only one vector of the cycle, i t was an advantage of the workshop to elucidate the whole process from source to man.
H. CASPERS