Short-run price formation in non-fuel minerals markets: An algebraic note

Simple flow models are inadequate for understanding short-run price behaviour in non-fuel mineral markets. In this note the author derives a simple model of mineral price behaviour in terms of stocks, and shows how this may successfully explain some short-term features of mineral price behaviour.     

End of the oil glut—state regulation of energy

The idea of confronting several hundred managers, politicians, and academics with 20 or so energy experts and celebrities to determine whether supplying the industrial world with energy is fundamentally a matter for the private sector or the state, may seem at first like an affront to common sense. After all, conferences, including those convened under the auspices of distinguished foundations, usually do not have any executive powers; and considering the uneven quality of the presentations, I suspect that the proceedings of this particular assembly will only have a limited readership in those spacious rooms adjoining the corridors of power. However, for reasons discussed below, this conference was a useful exercise. Energy Policy in the Market Economy, arranged by the Institut für Wirtschafts- und Gesellschaftspolitik, and sponsored by the Konrad-Adenauer-Stiftung, Bonn-Bad Godesberg, Germany, 29–30 May 1979.     

Leaching and reduction of chromium in soil as affected by soil organic content and plants

The oxidation state of chromium in contaminated soils is an important indicator of toxicity and potential mobility. Chromium in the hexavalent state is highly toxic and soluble, whereas the trivalent state is much less toxic and relatively insoluble. A laboratory study investigated the impact of growing plants and supplemental organic matter on chromium transport in soil. Plants alone had no appreciable effect on the chromium oxidation state in soil. Soil columns with higher organic content were associated with lower ratios of chromate:total chromium than the columns with lower organic matter. Analyses of column leachate, plant biomass, and soil indicate that more chromium leaching occurred in the vegetated, low organic columns. Retention of Cr in the soils was correlated to the Cr(III) content. Plant uptake of chromium accounted for less than 1% of the chromium removed from the soil. Overall, the addition of organic matter had the strongest influence on chromium mobility.     

Effect of root death and decay on dissipation of polycyclic aromatic hydrocarbons in the rhizosphere of yellow sweet clover and tall fescue

A 12-mo greenhouse study was conducted to evaluate the contribution of root death and decay on the dissipation of polycyclic aromatic hydrocarbons (PAHs) in rhizosphere soil. The contaminated soil was previously treated by land-farming, but residual PAHs remained after treatment. Tall fescue (Festuca arundinacea Schreb.) and yellow sweet clover (Melilotus officinalis Lam.) were the target plants. To specifically evaluate the effect of root decay on contaminant dissipation, plants were treated with glyphosate, a broad spectrum herbicide, to induce root decay. Although tall fescue treatments had the highest root and shoot biomass and root surface area, this plant did not result in the highest contaminant degradation rates. Significant differences were noted between treatments for seven PAHs, with the active yellow sweet clover resulting in 60 to 75% degradation of these compounds. Induced root death and decay did not produce a significant enhancement of PAH degradation. The PAH microbial degrader populations in the vegetated treatments were more than 100 times greater than those in the unvegetated control. The phospholipid fatty acid (PLFA) structural group profile shifted over the growing period, indicating a change in the community structure. In conclusion, phytoremediation was shown to be an effective polishing tool for PAH-affected soil previously subjected to biological treatment.