Application of the EPR spin-trapping technique for the investigation of the reactions of carbonate, bicarbonate, and phosphate anions with hydroxyl radicals generated by the photolysis of H2O2

The spin trapping technique with electron paramagnetic resonance (EPR) detection of spin adducts was applied for the investigation of the reaction of hydroxyl radicals, generated by the photolysis of hydrogen peroxide, with bicarbonate and carbonate anions. The results have been compared with those obtained for aqueous solutions of hydrogen peroxide as well as solutions containing phosphate buffers at pH values identical with those of the carbonate, and bicarbonate solutions. Both the carbonate, and bicarbonate anions quenched the hydroxyl radicals more efficiently than phosphate buffers. The effect depended on the anion concentrations, and it was most pronounced in the presence of carbonate. Rate constants for the reaction of OH with the investigated anions have been calculated. They are very close to values reported in the literature, obtained using optical detection of the carbonate and phosphate radicals.     

Trace metals in the roadside mountain soils of Sierra Nevada,Spain

The investigations were made to determine the total contents of Fe, Mn, Zn, Cu, Pb, Cd, Ni and Cr in the roadside soils and rocks of the Sierra Nevada Mountains in Spain. There were differences in both the age and lithology of the bed-rock in the study area. The surface soil layer is primarily enriched with lead in relation to the bed-rock, but zinc, manganese, and cadmium also occur.Lead, zinc and cadmium concentrations show a decrease with increasing distance from the road, whereas the levels of iron, manganese, copper, nickel and chromium do not show such a variation. The change in lead and zinc concentrations with increasing distance from the road is related to the topography of the area immediately adjacent to the road. On the descending slopes the concentrations of these metals remain unchanged or increase with the increasing distance from the road, whereas on the ascending slopes they show a clear decrease.     

Application of ‘Landsat’ data to resource management

Over the past few years, a great deal of interest has been focused on the use of remote sensing for resource management. This paper examines one of the most useful systems — Landsat. Included in this paper is a discussion of this remote-sensing technology, its application and its future as a tool for resources planning and management.     

Effects of copper and cadmium on osmoregulation and oxygen consumption in two species of estuarine crabs

Green crabs (Carcinus maenas) and rock crabs (Cancer irroratus) were exposed to various concentrations of copper as cupric chloride (CuCl₂ · 2 H₂O), and cadmium as cadmium chloride (CdCl₂ · 21/2 H₂O) for 48 h. The exposures were conducted at 5 different salinities. At the end of each exposure period, tests of blood-serum osmolality and gill-tissue oxygen consumption were performed. Copper-exposed crabs exhibited loss of osmoregulatory function with increasing copper concentration until normally hyperosmotic serum became isosmotic with the surrounding medium. Cadmium elevated greencrab serum above its normal hyperosmotic state. Copper had no effect on gill-tissue oxygen consumption; however, cadmium reduced the rate of oxygen consumption in both species tested.     

NADP+-isocitrat-dehydrogenase aus Idus idus (Pisces: Cyprinidae). I. Aktivität als funktion der adaptationstemperatur

Activity of NADP⁺-dependent isocitrate dehydrogenase (ICDH) of the white dorsal muscle of Idus idus L. was determined by special analysis, under optimum homogenisation, centrifugation and cuvette conditions. The experimental conditions differed considerably from those used for the investigation of NADP⁺-ICDH activity in mammals by Bücher et al. (1964). Daily measurements of activity over a period of 10 days revealed variations in enzyme activity which are difficult to explain. However, the variations are smaller than those established in earlier tests. In order to obtain statistically valid results, the highest possible number of test fishes (at least 10 individuals for each measurement) must be investigated over a period of 5 to 10 days. NADP⁺-ICDH of individuals acclimated to 10°C showed 28% higher specific and non-specific activity than that of fish maintained at 20°C (experimental temperature 25°C). At 5 different adaptation temperatures, increasing activities were observed with decreasing adaptation temperature (compensation). These measurements were made over a period of 5 successive days.