engleski

Rare earth element distribution in soil nearby thermal power plant

Rare earth element (REE) concentrations and their normalized counterparts were used to assess the influence of coal-fired power plant on surrounding soils. Research was conducted in the area of the thermal power plant (TPP) Plomin in Croatia. For purpose of study REEs were determined in several groups of samples ; (i) soils sampled at different distances from the TPP, from its very proximity to the distance of 10 km, (ii) coals from the nearby Raša mine used as a fuel in the TPP till late 1990s together with related ash and slag samples ; and (iii) ash produced by combustion of imported coal used from 1990s onwards. Results point to existence of differences among the analyzed ashes and sampled soils, in terms of REE concentrations as well as their normalized patterns. Highest REE levels were recorded in samples of recent ash, while concentrations of REE in soil samples decrease with distance from the TPP. Normalized patterns of soils sampled in the vicinity of TPP resemble the normalized patterns of recent ashes, exhibiting lower LREE enrichment compared to control soils. With increasing distance from the TPP, the soil samples display increasing fractionation between LREE and HREE, what is typical for the local unpolluted soil. The obtained results points to transfer of ash particles emitted from the TPP to the surrounding environment, with the greatest influence observed in the direction of the prevailing wind.

thermal power plant; rare earth elements; soil geochemistry ;

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