Cenchrus setaceus as a Roadside Passive Collector of PAHs and Trace Elements

Polycyclic aromatic hydrocarbons (PAHs) and trace elements (TEs) are widespread environmental contaminants of concern due to their potential impacts on environmental and human health. This study evaluates the invasive grass Cenchrus setaceus (syn. Pennisetum setaceum) as a passive collector of both PAHs and TEs across urban and coastal areas of Palermo, Sicily. Sampling campaigns were conducted at 12 sites with varying traffic intensity and anthropogenic pressure. PAH concentrations showed significant seasonal variation (PERMANOVA; p = 0.0042), with lowmolecular-weight compounds dominating in summer and higher-molecular-weight PAHs in winter. Diagnostic ratios pointed to mixed sources, primarily vehicular traffic and fossil fuel combustion, with additional contributions from biomass burning and domestic heating. Urban sites exhibited the highest contamination, with levels comparable to or exceeding those in other plant species. Elemental analysis showed moderate contamination and spatial variability, with Fe, Zn, Mn, and Cu as the most abundant elements. Spearman’s correlation analysis revealed significant associations among several elements, suggesting potential co-accumulation and shared sources, while Sr and Mo exhibited more independent behavior. Cenchrus setaceus, which thrives along roadsides and other anthropogenic habitats, can effectively reflect the atmospheric deposition of both organic and inorganic contaminants over time. Beyond its role as a passive collector, its tolerance to pollutants suggests an intrinsic “invasive phytoremediation” potential, contributing to pollutant attenuation while providing insight into local contamination. Consequently, it could represent a cost-effective resource for environmental assessment, integrating sensitivity to spatial and seasonal variability with remediation capacity. Biomass collected during control or eradication efforts can further support integrated approaches by enabling environmental monitoring, aiding invasive species mitigation, and providing valorization pathways, including the production of bio-based building materials [1]. Despite requiring careful control, its widespread occurrence along roadsides offers a strategic advantage for incorporation into sustainable biomonitoring frameworks. References [1] M. Charai, M. Salhi, et. al., 2022, Construction and Building Materials, https://doi.org/10.1016/j.conbuildmat.2022.126809.