Wild and ruderal plants as bioindicators of global urban pollution by air, water and soil in Riyadh and Abha, Saudi Arabia

Recently, environment pollution around the globe has increased because of anthropogenic activities. As part of the biota, plants can assimilate the compounds present in air, water and soil and respond to changes in surround conditions, for that, they can be used as bioindicators of global pollution. However, urban plants' ability to monitor organic pollutants in air, soil, and water have not been profoundly studied yet. Anthropogenic contamination produced by five different types of pollutants [polycyclic aromatic hydrocarbons (PAHs), pharmaceuticals and personal care products (PPCPs), perfluoroalkyl substances (PFASs), pesticides and organophosphorus flame retardants (OPFRs)] has been studied in Riyadh and Abha areas (Saudi Arabia). In addition to the points in both cities, a control point located in the Asir National Park (close to Abha), which is little affected by human activity, was used. The 5 groups of contaminants were found with different but high detection frequencies from 85 % to 100 % in wild and ruderal plants. PAHs were detected in all the analyzed samples at the highest average sum of concentrations (EPAHs) 1486 ng center dot g-1 dry weight (d.w.). Statistically significant differences were obtained between Riyadh, Abha and the point located in the national park (p < 0.05). EPAHS in Riyadh >> EPAHs in Abha > EPAHs in the National Park. Values of the average sum of concentrations for the other groups of contaminants EPPCPs, EPFASs, Epesticides and EOPFRs were 420.5, 171, 48 and 47 ng g-1 d.w., respectively. High values of PPCPs are due to the presence of salicylic acid. Differences in the average sum of each type of contaminant concentrations between cities were not statistically significant. The results of this assessment of wild and ruderal plants as bioindicators for 5 types of organic contaminants suggest that they can be used to monitor anthropogenic contaminants in the terrestrial environment.

Automated summary

Recently, the increase in environmental pollution worldwide due to human activities has become a concern. Plants, being part of the biota, can serve as bioindicators of global pollution as they have the ability to assimilate compounds in the air, water, and soil, and respond to changes in their surroundings. However, the monitoring ability of urban plants regarding organic pollutants in air, soil, and water has not been extensively studied. This study focused on the anthropogenic contamination produced by five different types of pollutants in Riyadh and Abha areas in Saudi Arabia and found that wild and ruderal plants have high detection frequencies of polycyclic aromatic hydrocarbons (PAHs), pharmaceuticals and personal care products (PPCPs), perfluoroalkyl substances (PFASs), pesticides, and organophosphorus flame retardants (OPFRs). The results suggest that these plants can be used as bioindicators to monitor anthropogenic contaminants in the terrestrial environment.