Lead and Cadmium Content in Grass Growing Near An Expressway.

The purpose of the study was to evaluate the effect of distance from a road on lead and cadmium content in grass species near an expressway and to assess bioaccumulation of these elements by morphological parts of the plants. The material for the research was the following grass species in their flowering stage: Dactylis glomerata, Arrenatherum elatius, and Alopecurus pratensis. Plant samples were collected along the international E30 road, the ring-road of Siedlce, in May 2015. A 9-km road section was examined with samples collected on both sides, covering a stretch of 700 m, at the following distances from the edge of the road: 1, 5, 10, and 15 m. Five samples of each plant species and at each distance from the road were collected. Lead and cadmium concentration was determined with the AAS method. The largest amounts of Pb were absorbed by A. pratensis L. (3.843 mg kgDM), while the lowest by A. elatius L. (2.523 mg kgDM). Of the above plants, the highest amount of Cd (0.286 mg kgDM) was accumulated by D. glomerata L. Underground parts of the grass species accumulated greater amounts of Pb and Cd than aboveground parts. It indicates that considerable amounts of heavy metals released by expressway vehicles contaminated the soil. The highest content of Pb and Cd was found in the grass growing at a distance of 5 m from the edge of the roadway, and this applies both to underground and aboveground parts.