In this study, the leaves, bark and the soil supporting Populus x canadensis Moench were tested as a possible biomonitor of trace
element pollution in the Middle Black Sea region of Turkey. The investigations were carried out at 23 sites. The leaves, bark and soil were
analyzed for Pb ++ , Cd ++ , Fe ++ , Cu ++ and Zn ++ contents. The values of Pb ++ , Cd ++ , Fe ++ , Cu ++ and Zn ++ in the leaves varied between 14.5-40.0,
0.5-1.5, 135-486, 5.0-14.0 and 43-246 ppm, respectively. In the bark the values were between 15.5-36.5 (Pb ++ ), 1.5-2.0 (Cd ++ ), 39-575
(Fe++), 5.0-14.0 (Cu ++ ) and 40.0 –1468 ppm (Zn ++ ), whereas in the soil values for Pb ++ were 1.0-4.1 ppm, for Cd ++ 0.2 ppm, for Fe ++ 0.6-1.8
ppm, for Cu ++ 0.1-0.9 ppm and for Zn ++ 0.1-1.9 ppm. A positive correlation was found between traffic density and the amount of Pb ++ , Fe ++
and Cu ++ in leaves, while a negative correlation was documented for Cd ++ and Zn ++ . In the bark samples there was a positive correlation
between traffic density and Pb ++ , and a negative one with Cd ++ , Fe ++ , Cu ++ and Zn ++ . A positive correlation was determined between traffic
density and the amount of Pb ++ , Fe ++ , Cu ++ and Zn ++ in soil. However, the amount of Cd ++ was 0.2 ppm and no relationship between Cd ++ and
traffic density was observed.