Earticle

Background: Phosphate rock and its by-product are widely used in various industries to produce phosphoric acid, gypsum, gypsum board, and fertilizer. Owing to its high level of natural radioactive nuclides (e.g., 238U and 226Ra), the radiological safety of workers who work with phosphate rock should be systematically managed. In this study, 238U, 232Th, 226Ra, and 40K levels were measured to analyze the transport characteristics of these radionuclides in the production cycle of phosphate rock. Materials and Methods: Energy dispersive X-ray fluorescence and gamma spectrometry were used to determine the activity of 238U, 232Th, 226Ra, and 40K. To evaluate the extent of secular disequilibrium, the analytical results were compared using statistical methods. Finally, the distribution of radioactivity across different stages of the phosphate rock production cycle was evaluated. Results and Discussion: The concentration ratios of 226Ra and 238U in phosphate rock were close to 1.0, while those found in gypsum and fertilizer were extremely different, reflecting disequilibrium after the chemical reaction process. The nuclide with the highest activity level in the production cycle of phosphate rock was 40K, and the median 40K activity was 8.972 Bq·g-1 and 1.496 Bq·g-1, respectively. For the 238U series, the activity of 238U and 226Ra was greatest in phosphate rock, and the distribution of activity values clearly showed the transport characteristics of the radionuclides, both for the byproducts of the decay sequences and for their final products. Conclusion: Although the activity of 40K in k-related fertilizer was relatively high, it made a relatively low contribution to the total radiological effect. However, the activity levels of 226Ra and 238U in phosphate rock were found to be relatively high, near the upper end of the acceptable limits. Therefore, it is necessary to systematically manage the radiological safety of workers engaged in phosphate rock processing.

Concerns about economies facing secular stagnation?a period of persistently lower growth?have been renewed after the start of the financial crisis in 2008~2009. This issue is well investigated for the euro area as a whole or for the individual countries forming the monetary union, with the general consensus being that secular stagnation is not present in the Economic and Monetary Union (EMU). So far no studies have been conducted for the remaining European countries, and thus this study tackles this issue for the five non-EMU European countries using the well-established Laubach? Williams model to estimate the unobservable equilibrium real interest rate and compare it with the actual real rate. The obtained results have important implications for national policymakers, i.e., if secular stagnation is present in one country, then there is a risk of growth divergence with the country’s most important trading partners. The results also indicate that secular stagnation is not a significant threat to the non-EMU European countries, so they do not face structurally different growth dynamics compared with those of the euro area.