Heavy Metals Phytoremediation and Its Impact on Photosynthetic Pigments and Metabolic Content in Some Plant Species Grown in the Streets of Jeddah Governorate, Saudi Arabia

Abstract

In Jeddah governorate, increased industrialization, urbanization and vehicular traffic may raise levels of heavy metals in the air and soil, threatening food safety and human health. Roadside vegetation traffic barriers might be an effective way to enhance roadside air quality and reduce human exposure to vehicular pollution. This study was conducted in order to uncover the best-cultivated plant species for purifying polluted air in terms of environmental parameters. The samples for this study were obtained from several locations throughout Jeddah governorate streets. The main causes of air pollution in the study area are traffic and automobile emissions. Photosynthetic pigments, soluble sugars, soluble protein, amino acids, and proline in plant extracts were investigated in the plant species used in this study. Also, the ionic composition (K, Na Ca and Mg), as well as the heavy metals (Zn, Cr, Ni, Cd, Pb, Co and Ba) in the sampling sites, as well as roots and leaves of the collected plant samples were all assessed. Plant examination revealed that I. coccinea possessed the highest value of Chl b, soluble proteins and sugars, while T. stans exhibited the highest amount of Chl a, carotenoids and amino acids. Furthermore, the most common contaminants in all sites were Zn, Ba, and Ni, with Zn and Ba being the most actively accumulated in the leaves of the studied plants. The findings revealed that the root of C. lancifolius is a powerful phytoaccumulator of Zn, Ni, and Co. In addition, C. lancifolius, I. coccinea, Z. spina-christi, and B. spectabilis were shown to exhibit high accumulating potential of various polluting metals in their roots. Also, Zn, Ba, Ni, and Cr were the most efficiently transmitted metals to the leaves of the studied plants. Consequently, these plant species can be employed in phytoremediation approaches at contaminated sites.