Assessment of soil contamination by ~(210)Po and ~(210)Pb around heavy oil and natural gas fired power plants

摘要

Soil contamination by ~(210)Pb and ~(210)Po around heavy oil and natural gas power plants has been investigated; fly and bottom ash containing enhanced levels of ~(210)Pb and ~(210)Po were found to be the main source of surface soil contamination. The results showed that ~(210)Pb and ~(210)Po in fly-ash (economizer, superheater) is highly enriched with ~(210)Pb and ~(210)Po, while bottom-ash (boiler) is depleted. The highest ~(210)Pb and ~(210)Po activity concentrations were found to be in economizer ash, whereas the lowest activity concentration was in the recirculator ash. On the other hand, ~(210)Pb and ~(210)Po activity concentrations in soil samples were found to be higher inside the plant site area than those samples collected from surrounding areas. The highest levels were found in the vicinity of Mhardeh and Tishreen power plants; both plants are operated by heavy oil and natural fuels, while the lowest values were found to be in those samples collected from Nasrieh power plant, which is only operated by one type of fuel, viz. natural gas. In addition, the levels of surface soil contamination have decreased as the distance from the power plant site center increased.