Determination of uranium isotope concentrations in precipitation in the vicinity of lignite-fired power plants

Coal- and lignite-fired power plants produce significant amounts of fly ash, which in many cases contains high concentrations of naturally occurring radionuclides such as 238U. This is of importance from the radio-environmental point of view since a small portion of the fly ash escapes from the power plant filtering system and disperses in the surrounding atmosphere. In addition, coal- and lignite-fired plants related activities such as fuel mining and ash deposition contribute to the suspended matter in the air with particles containing naturally occurring radionuclides. In this study, rainwater samples were collected in the Megalopolis lignite field basin of the Arcadia prefecture in Greece, where lignite-fired power plants are in operation and related activities are fully developed. The samples were preconcentrated and analyzed with alpha spectrometry and kinetic phosphorescence analysis in order to determine the levels of uranium isotope concentrations in precipitation in the Megalopolis basin. A control rainwater sample was also collected in the Athens area to account for reference purposes. Concentrations determined via the two techniques were found to be in statistical agreement. The concentration of 238U in the samples collected at the Megalopolis basin varies from 2.2 ? 0.6 to 90 ? 14 mBq/L, and is 5-40 times higher than the concentration of 238U in the sample collected in Athens. This could be attributed to the operation of the lignite-fired power plants, the fossil fuel mines, and the ash depositories.

Hurricanes Pauline and Nora rainwater chemical composition

Rainwater from hurricanes Pauline and Nora was sampled for chemical analysis at the Pacific Coast of Mexico. Rainwater sampling under extreme conditions presents a unique opportunity to study oceanic rain chemical composition. An excess sulphate ((SO2–4)xs) as low as 0% was measured near the centre of hurricane Pauline in Huatulco Bays. Another remarkable result was obtained in another rainwater sample of Pauline rain bands with a total SO2–4 concentration below the detection limit. Also, Na+ and Cl– concentrations were extremely low (0.02 and 0.025 mg L–1, respectively). The explanation of these results is also presented. Some light rains were also collected in Tapachula while Pauline was severely affecting Huatulco Bays. Only rainwater samples from hurricane Nora outer rain bands were sampled in Manzanillo, where it was interesting to evaluate the profound impact that a single power plant had on the chemical composition of hurricane Nora rains. Excess sulphate did not correlate with Mg2+ in Huatulco Bays and Manzanillo. However, it correlated with Mg2+ in Tapachula, even though this town is located 27 km from the coast. A further oxidation of organic sulphur containing compounds combined with a simultaneous transport of sea spray inland is proposed to explain this correlation.