Survey of Metals

The problem is to assess the flux of trace metals at critical points in the marine realm ascribable to each of the pathways. 

Alterations in trace metal concentrations in the marine environment due to man s activities are difficult to establish, since natural levels are often poorly known, or when known show variations. At present, measurement of concentration gradients (both vertical and horizontal) from known pollution sources is the primary method to assess trace metal contamination of the marine environment. High trace metal inputs into estuarine or coastal areas from industrial effluents as well as from river run-off have been measured. Without knowledge of the make-up of these source materials, distinguishing between a natural and an anthropogenic origin for increased metal concentrations is an insoluble problem. 

Estimates of potential trace metal oceanic input based on atmospheric washout, mining productivity figures, and relative river transport are given in Tables 1 and 2. 

Estimates have been prepared for mercury and other metals for atmospheric inputs to oceanic systems. Table 1 gives these estimates for oceanic waters based on ratios of current urban air values to average crustal material values. Both lead and cadmium have higher enhancement ratios (2,300 and 1,900) than mercury (1,100). When percent increase estimates are made for ocean concentrations, the concentration range for cadmium is 0.02 to 8 jug/1, and for mercury 0.1 to 0.8 /Ltg/1. No probable percent increase is given for lead. 

Element Open ocean (Mg/l) U.S. urban air (jug/m3)1) Enhancement Ratio ratio in air2) air/ocean High Most probable 

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Metal vapor chemistry showed that the lanthanides had quite an extensive chemistry with unsaturated hydrocarbons. Some of the early surveys of metal vapor reactions with unsaturated hydrocarbons included some lanthanide metals and showed that reactivity was present for these metals (14-18). Subsequent synthetic studies in which the products were isolated and characterized led to some of the most unusual organolanthanide complexes currently known (19-28). 

Recent surveys of metal-deficient stars have discovered a large number of carbon-rich objects, with a marked increase in their frequency at [Fe/H] < —2.5. In order to constrain the origin(s) of their carbon excesses, we have performed elemental abundance analyses for 40 objects selected from candidate metal-poor stars with strong CH G bands identified in the HK and Hamburg/ESO surveys. High-resolution spectroscopy has been obtained with AAT/UCLES and Subaru/HDS a portion of these studies have already been published [1—3]. 

Eisler, R., R.L. Lapan, Jr., G. Telek, E.W. Davey, A.E. Soper, and M. Barry. 1977. Survey of metals in sediments near Quonset Point, Rhode Island. Mar. Pollut. Bull. 8 260-264. 

Eggins and McNeill compared the solvents of water, dimethylsulfoxide (DMSO), acetonitrile, propylene carbonate, and DMF electrolytes for C02 reduction at glassy carbon, Hg, Pt, Au, and Pb electrodes [78], The main products were CO and oxalate in the organic solvents, while metal electrodes (such as Pt) which absorb C02 showed a higher production for CO. In DMF, containing 0.1 M tetrabutyl ammonium perchlorate and 0.02 M C02 at a Hg electrode, Isse et al. produced oxalate and CO with faradaic efficiencies of 84% and 1.7%, respectively [79], Similarly, Ito et al. examined a survey of metals for C02 reduction in nonaqueous solution, and found that Hg, Tl, and Pb yielded primarily oxalate, while Cu, Zn, In, Sn, and Au gave CO [80, 81]. Kaiser and Heitz examined Hg and steel (Cr/Ni/Mo, 18 10 2%) electrodes to produce oxalate with 61% faradaic efficiency at 6 mA cm-2 [82]. For this, they examined the reduction of C02 at electrodes where C02 and reduction products do not readily adsorb. The production of oxalate was therefore explained by a high concentration of C02 radical anions, COi, close to the surface. Dimerization resulted in oxalate production rather than CO formation. 

Furst A, Haro RT. 1969. A survey of metal carcinogenesis. Prog Exp Tumor Res 12 102-133. 

Hering, J. G., and F. M. M. Morel, The kinetics of trace metal complexation Implications for metal reactivity in natural waters, pp. 145-171 in Aquatic Chemical Kinetics, ed. by W. Stumm, Wiley, New York, 1990. A survey of metal complexation kinetics and mechanisms written with applications in mind a fine complement to the book by Burgess cited above. 

Survey of Metal Deposition from Nonaqueous Organic Electrolytes. 172... 

To build up a theory of metallic phase stability the conventional arguments for the discussion of crystal structures have to be completed by the concept of spatial correlation of electrons. The parameters of the spatial correlations may be analyzed from the ample empirical material of determined crystal structures by means of several evident rules. The surprising result is that for many crystal structures two correlations are essential for understanding the special features of the crystal structures. This two-correlations model makes possible an easy survey of metallic structures. Two examples of crystal structure-type families are considered, the Cu-family and the W-family. 

CuLBARD E, Moorcroft S, Watt j and Thornton I (1983) A nationwide reconnaissance survey of metals in urban dusts and soils. Minerals and the Environment 5 82-84. 

Table 2-1 gives a survey of metals essential for life and summarizes the amounts of metals in the human body. The question is, what makes the function of these around twenty-five elements so valuable in making life. Some metals are necessary in gram quantities. Other trace elements such as Mn, Mo, Co, V, W, Ni and Cr are essential beneficial nutrients at low levels but metabolic poisons at high levels. Some metal ions such as Pb, Cd are called detrimental metal ions because they are toxic and impair the regular course of life functions at all concentrations. 

In 1989, Orpen and co-workers reported a systematic survey of metal-ligand bond distances organized by metal, ligand, and bond type for < -block and /-block metals. This tabulation was based on ca. 10,000 of the most... 

Jones, M. M., Elementary Coordination Chemistry, Prentice-Hall, Englewood Cliffs, New Jersey, 1964. A thorough survey of metal ion-ligand chemistry. Chapter 8 presents methods of measuring equilibrium constants. 

Introduction and General Survey of Metal-Metal Bonds... 

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