Contamination of soils with Cu, Na and Hg due to the highway and railway transport

Abstract

Contamination of soils with three metals due to the highway and railway transport wasstudied. Copper was selected as a suitable indicator for both kinds of transportation.Sodium served to assess the level of contamination resulting from the road salting inwinter. Mercury was determined in samples taken close to the railway in order to testits release from impregnated wooden ties. All analytes were determined using themethods of the trace element analysis; values are expressed as dry matter. The highestconcentrations of copper, sodium and total mercury in soil samples were 52.7 mg/kg,770 mg/kg and 0.181 mg/kg respectively. The highest copper content was observed insoils taken close to the railroad and the highway. Elevated sodium levels originatedfrom winter road salting – the highest winter value was 770 mg/kg as compared withmaximal summer value of 416 mg/kg. The concentration of total mercury in soilsdepended on the type of railway ties used – the highest values for location with woodenand concrete ties were 0.181 mg/kg and 0.145 mg/kg, respectively. Wooden railroadties are considered as a potential source of mercury because of impregnation withantifungal mercury compounds.