The assessment of roadside pollutants and it's impact on metalic and chlorophyll content of Nerium oleander L. and Phragmites australis L. in Arbil city.

Abstract

This study was dealed with the effects of some roadside pollutants on two species Nerium oleander L. and Phragmites australis L. plants grown on roadsides and subroadsides within Arbil city selecting 14 sites, in addition to 4 control sites in rural regions. The samples were collected monthly intervals, from October 2002 to June 2003. The results showed that Pb concentration was higher than the normal range. The high concentration of 65.39 ppm found in N. oleander and of 47.86 ppm in P. australis at sites with high traffic density, these values more than of control sites (10.34 and 8.43 ppm for each species). In regard to Cd in most samples of study sites for both species except in P. australis in control group were within the range of 0.323 and 0.652 ppm. This was higher than that naturally occurring in plant material. The concentration of Zn, Fe and S was ranged from 10.76 – 51.17 ppm, 16.314 – 58.0 4 ppm and 207.159 – 485.186 ppm respectively. This study showed a positive correlation between leaf nitrogen (0.433-1.401%) and total chlorophyll content(1.435 - 2.467 mgg⁻¹) except in some sites. Whereas, in regard to phosphorus it was affected on total chlorophyll content through it's effect on other elements such as Zn, Fe and S. The significant differences (p < 0.05) as affected by sampling sites and time of sampling except in few cases. Also N. oleander plant was more sensitive and less tolerance than P. australis for the roadside pollutant as originated from vehicles exhaust emission inside the city. Generally, the concentration of studied air pollutants in plants adjacent to roadsides were higher than of farsides. They were relatively high in summer and low in wenter. The results revealed that all studied air pollutants were relatively in level below the degree of injuring plants.