Polycyclic aromatic hydrocarbons in the leaves of twelve plant species along an urbanization gradient in Shanghai, China

Abstract

Plants, particularly their leaves, play an important role in filtering both gas-phase and particle-phase polycyclic aromatic hydrocarbons (PAHs). However, many studies have focused on the accumulation and adsorption functions of plant leaves, possibly underestimating the effects that plants have on air quality. Therefore, eight tree species from different locations in Shanghai were selected to assess PAH filtering (via adsorption and capture) using washed and unwashed plant leaves. The differences in the total PAH contents in the washed leaves were constant for the different species across the different sampling sites. The PAH levels decreased in the following order: industrial areas > traffic areas > urban areas > background area. The PAH compositions in the different plant leaves were dominated by fluorene (Fle), phenanthrene (Phe), anthracene (Ant), chrysene (Chr), fluoranthene (Flu), and pyrene (Pyr); notably, Phe accounted for 49.4-76.7% of the total PAHs. By comparing the PAH contents in the washed leaves with the PAH contents in the unwashed leaves, Pittosporum tobira (P. tobira), Ginkgo biloba (G. biloba), and Platanus acerifolia (P. acerifolia) were found to be efficient species for adsorbing PAHs, while Osmanthus fragrans (O. fragrans), Magnolia grandiflora (M. grandiflora), and Prunus cerasifera Ehrh. (P. cerasifera Ehrh.) were efficient species for capturing PAHs. The efficiencies of the plant leaves for the removal of PAHs from air occurred in the order of low molecular weight > medium molecular weight > high molecular weight PAHs.

Distribution and Relationships of Polycyclic Aromatic Hydrocarbons (PAHs) in Soils and Plants near Major Lakes in Eastern China

“…In urban soils in China [ 31 ], soils of the Yangtze River Delta [ 40 ] and soils of the Yinma River Basin [ 41 ], the content of Phe is not the highest, but it still ranks in the forefront. For PAHs in plants, the dorminance of Phe has also been found in other studies [ 42 , 43 ].…”

Moss and Polyaromatic Hydrocarbon in Malaysia: A Recent Ten-Year Evaluation

“…The influencing factors in retaining PAHs depend on leaf morphology (species, leaf, branch) and the abundance of stomata, trichomes, and cuticular wax. Studies showed that the coated wax on leaf surfaces and stomata aids plants in battling dust and airborne elements attached to or trapped in (Muhammad Waqar Ashraf & Salam, 2012;Liang et al, 2017). Although PAHs accumulate mainly on the products surface, due to their lipophilic nature, some diffusion can occur to inner layers (Alagić et al, 2015), where water activity and fat content have a determinant role in migration rate (Gomes et al, 2013).…”

Solvent-Free Determination of Selected Polycyclic Aromatic Hydrocarbons in Plant Material Used for Food Supplements Preparation: Optimization of a Solid Phase Microextraction Method

“…However, few studies have reported the application of this technique to monitor the contamination of plants or trees [ 27 , 28 ]. Indeed, the evaluation of urban plants’ contamination by PAH is reported by more classical analytical approaches, such as solid–liquid extraction, mostly using chlorinated solvents [ 29 , 30 , 31 , 32 ].…”