The determination of the extractability of selected elements from agricultural soil

Concentrations of Ag, Al, Ba, Cd, Co, Cr, Cu, Fe, K, Mn, Na, Ni, Pb, Sr, and Zn—isolated by sequential extraction steps from apple orchard soil—were analyzed by inductively coupled plasma-atomic emission spectroscopy and compared to the total amount of metal in soil determined by XRF. The extractable amount of each metal was calculated by the extraction yields of the four steps. The LODs of the different elements in all extracts ware below 3 μg/L except for Ba (steps 1 and 2), Cu (step 1), Fe (all steps), K (steps 1–3), Mn (step 2), Na (steps 1–3), Ni (step 1), Pb (steps 1 and 4), and Zn (steps 1 and 2). The highest LOD (>10 μg/L) was found for Fe, K, and Na (step 1). The recovery of all metals after four sequential extraction steps was 90–112%. The repeatability (<1.1%), the intermediate precision (<5.3%), the day-to-day reproducibility (<6.2%), and the overall uncertainty of measurement (approximately 4–8.5%) for all analyzed metals supports the choice of the method used.     

The responses of the hepatosomatic index (HSI), 7-ethoxyresorufin-O-deethylase (EROD) activity and glutathione-S-transferase (GST) activity in sea bass (Dicentrarchus labrax, Linnaeus 1758) caged at a polluted site: implications for their use in environmental risk assessment

The present study investigates the response of three hepatic biomarkers in adult sea bass (Dicentrarchus labrax, Linnaeus 1758) caged at a wastewater outlet of an oil refinery with fish caged at a pristine site used as controls. The biomarkers that were investigated were the hepatosomatic index (HSI), 7-ethoxyresorufin-O-deethylase (EROD) activity and glutathione-S-transferase (GST) activity. In addition, we have measured the levels of polycyclic aromatic hydrocarbons (PAHs) and selected heavy metals (lead, cadmium, mercury, copper and zinc) in sediment samples at the polluted site. Although the polluted site had high environmental levels of PAHs and heavy metals, there was no difference in hepatic EROD activity and HSI between fish caged at the polluted site and controls. On the other hand, GST activity was significantly lower in fish caged at the polluted site compared to controls. Our results point out that the studied biomarkers have limited use in environmental risk assessment studies, at least when caged adult sea bass is used as the sentinel species and complex toxicant mixtures are involved.     

Environmental and Economic Criteria in Ranking of Copper Concentrates

Influence of the economic criterion, called Profit, on the ranking of copper concentrates is investigated. Values of the criterion, which correspond to alternatives, are derived as earning values obtained by the exploitation of individual concentrates. Various scenarios with respect to the weight w ₁₄, corresponding to the additional economical criterion, are defined and solved. A discrete set of results is generated, applying DECISION LAB software implementation of the PROMETHEE-GAIA methodology. Interpolating these results, we derived continuous interpolation functions which compute necessary quantities of concentrates for each real value of w ₁₄ within the interval [0, 100].     

Environmental tritium of the Danube basin in Yugoslavia

An overview of environmental distribution of tritium in the Danube basin in Yugoslavia during the period 1976-1990 is presented. Temporal and regional variations of environmental tritium in the Danube along its flow (1425-847 km from the confluence) and its tributaries (the Sava, the Tisa, the Velika Morava and the Timok) at various locations, as well as in alluvial groundwaters, are given. In Belgrade, monthly values of tritium in rainfall ranged from 1.1 to 18.3 Bq litre(-1), with a maximum in the late spring and early summer months. The half-life for decline in concentration was estimated as 8.3+/-1.0 years. The total amount of tritium deposited in the first 6 months during 1976-90 was 35% larger than in the second 6 months for the same period. Seasonal variations were noticeable in rivers and groundwaters, but these were greatly attenuated and smoothed for the latter. Tritium content in the monthly composite samples from the river in the Belgrade region varied between 2.5 and 18.2 Bq litre(-1) for the Danube and from 1.5 to 16.8 Bq litre(-1) for the Sava. The yearly mean values along the Danube and its tributaries ranged from 2.4 to 15.9 Bq litre(-1) with individual measurements 1.0-30.2 Bq litre(-1). The half-lives were between 6.9+/-1.7 for the Velika Morava and 9.4+/-0.9 for the Danube. Groundwaters, particularly ones in the Ranney wells, followed changes of tritium content in the rivers with a time lag from a few days to a month. During the period of observation, tritium content decreased in alluvial waters with half-lives from 9.9+/-1.6 (Belgrade area) to 7.3+/-1.8 (the Velika Morava).     

Kinetic sodium analyses in the crab Carcinus mediterraneus

Kinetic analyses were made of the stable sodium and radioactive sodium (²²Na) in some tissues of the crab Carcinus mediterraneus CSRN. Fast ²²Na outflux constant is increased in gills, hepatopancreas, hemolymph, digestive tract and muscles. In the reproductive organs the values of the sodium outflux constant are lower. The values of the fast outflux rates (t=20°C) of sodium amount, in the whole animal, to 22.5 M Na/g/h, in the hemolymph, to 69.3 M Na/g/h; the slow outflux rates have much lower values (0.02 to 0.13 M Na/g/h). Moulting crabs show a rate of sodium outflux 6 times greater than that of intermoulting individuals.