[en] This work describes the method and Instrumentation used by Environmental Isotopes laboratory of the CIEMAT Analytical Chemistry Laboratory (DIAE) for the synthesis of benzene from carbonates of mollusk shells and the liquid scintillation counting of 14^C for radiocarbon dating in these samples. The usefulness of mollusk shells for 14^C dating are considered. (Author) 15 refs

[en] Concentration of tritium in environmental samples (air, precipitation) has been determined during 1998-2000, by using electrolytic enrichment and liquid scintillation counting. Atmospheric tritium concentration of tritiated water vapor (HTO), expressed in Bq/l varies within a range of 0,77-10.82 giving an overall average value of 1,81±1,82. HTO expressed in mBq/m''3 air varies within a range of 4,6-70; no correlation with the atmospheric humidity was observed. Tritium concentration in the precipitation ranges from 0.35 to 2,18 Bq/l, without seasonal variations. The tritium concentration in the air of the laboratory was approximately five times higher than in the atmosphere due to evaporation of tritium standard water during the process of the samples. (Author) 9 refs

[en] In this first report it is described the synthesis, separation and purification of the 2-radioiodinated histamine- I-labelled histamine by a mixed anhydride reaction. About 75% incorporation of I^-125, from Na¹25I, was achieved with a molecular ratio of 1:1 mixed anhydride:histamine. The radiochemical purity of the conjugate by TLC was > 99% and its theoretical specific activity, 3850 μCi/μg. Dissolved in ethanol and held at -20 degree centigree under darkness decomposition on storage didn't exceed 1% per month. (Author) 13 refs

[en] To assess bioremediation as a remedial action in sensitive environments, 18 plots, consisting of a 5m x 5m perimeter and an elevated scaffold system to permit sampling, were oiled with a 'weathered' Arabian light crude oil. The oil was applied evenly onto wetland sediment during low tide. Three treatments, - control, inorganic nutrients, and inorganic nutrients plus nitrate as an alternate electron acceptor - were administered. Sediment samples were analyzed for petroleum chemistry, inorganic nutrients, toxicity and microbial counts. There was no significant difference in test results among the various treatment methods for total extractable materials, however, target compound analysis indicated significant differences in the biodegradation rates for the three treatments. Biodegradation of 95 per cent of target compounds was observed within an average of 167, 80 and 118 days for the control, nutrient, and nutrient plus nitrate treatments, respectively. 12 refs., 6 figs