Roadside pollution of cadmium and lead in Istanbul City (Turkey) and their effects on Picea abies

Abstract

Evaluation of metal pollution in soils and plants is of environmental importance due to their negative effects. Surface soil and samples of Picea abies (L.) KARST. needles were collected along two contaminated roadsides from urban environment and analysed for metal content. Soil cadmium (Cd) and lead (Pb) concentrations in these sites averaged 0.46 and 209.5 mug g(-1) DW, respectively. In the unwashed 1-year and 2-year old needles the Cd concentrations averaged 0.15 and 0.22, and Pb concentrations averaged 58.6 and 84.9 mug g(-1) DW, respectively. These values lowered in the washed needle samples. Chlorophyll content, peroxidase activity of the needles and annual ring width differences were determined to identify toxic damage of roadside Cd and Pb pollution. Decrease in chlorophyll content and increase in peroxidase activity were detected in the needles. These results were more evident in the 2-year old ones due to the time of exposure. We have not observed a reduction in the annual ring widths related to Cd or Pb, but precipitation may have an effect on them. We suggest that Cd and Pb concentrations determined in this investigation affect chlorophyll biosynthesis negatively and induce the increase in the activity of peroxidase enzyme as a stress response in Picea abies needles.