Pine needles (Pinus sylvestris L.) as bioindicators in the assessment of urban environmental contamination with heavy metals

The studies on Zn, Pb and Mn content in the needles of Pinus silvestris and the surface layers of soil (0.0–0.2 m and 0.4–0.6 m) were conducted in 2010. The research stations covered residential areas, municipal parks, neighborhoods of busy streets, industrial establishments, waste dump sites and sewage treatment plants. The tests showed variability of the analyzed elements in the needles of P.silvestris and in municipal soils, depending on concentration of urban and industrial activity, road traffic and the depth of the examined layer of soil. The content of heavy metals in soil varied. Zn was character-ized by the highest variability, depending on the depth (50.3–52.4%), Mn slightly lower (38.5–42.2%), and Pb, the lowest (29.1–33.2%). It was evidenced that the values of the heavy metals enrichment factors of the needles are closely connected with concentration of the examined metals in the soil. Along with the rise of Zn, Mn and Pb content in the soil, the values of enrichment factors decreased. The strongest negative correlations were found in the case of Zn, both in 1-year old needles (r = -0.82, p<0.05), as well as in 2-years’ old ones (r = -0.83, p<0.05), slightly weaker in the cases of lead and manganese.