This study aimed to provide insight regarding the influence of Ce oxide nanoparticles (nCeO2) with different concentrations and two different particle sizes on the germination and root elongation in seedlings of spontaneous terrestrial species. In a bench-scale experiment, seeds of the monocot, Holcus lanatus and dicots Lychnis-flos-cuculi and Diplotaxis tenuifolia were treated with solutions containing nCeO2 25 nm and 50 nm in the range 0–2000 mg Ce L−1. The results show that nCeO2 enters within the plant tissues. Even at high concentration, nCeO2 have positive effects on seed germination and the development of the seedling roots. This study further demonstrated that the particle size had no influence on the germination of L. flos-cuculi, while in H. lanatus and D. tenuifolia, the germination percentage was slightly higher (+10%) for seeds treated with nCeO2 25 nm with respect to 50 nm. In summary, the results indicated that nCeO2 was taken up by germinating seeds, but even at the highest concentrations, they did not have negative effects on plant seedlings. The influence of the different sizes of nCeO2 on germination and root development was not very strong. It is likely that particle agglomeration and ion dissolution influenced the observed effects.

Mercury (Hg) poses environmental and health risks due to its global distribution and high toxicity exhibited in some of its chemical forms. Although Hg is naturally present in the environment, human activities\ud have increased its cycling among the land, atmosphere and ocean by a factor of three to five comparing the pre-industrial period to the present day. The Torviscosa chlor-alkali plant (CAP), which operated\ud since the beginning of twentieth century, was one of the most important Cl2 production capacity in the Northern Italy and was responsible for an uncontrolled discharge of Hg in the surrounding area. Previous studies reported the high degree of Hg pollution in soils, river sediments and surface waters of the area, but the Hg level in the atmospheric media was never taken into consideration. In this work, an integrated approach was applied with the aim to assess the level, distribution and dispersion of gaseous elemental mercury (GEM) close to the CAP area. GEM levels were monitored by means of four surveys conducted from September 2014 to July 2015, at fixed locations and covering an area of about 10 km2 (including CAP area, Torviscosa village and reclaimed land), accomplished to Hg bioaccumulation measurements in selected lichens. The results indicate that the CAP area currently represents the main source of GEM in the Friuli Venezia Giulia region. The highest levels were found close to the old factory’s buildings (more than 5000 ng m−3), whereas other sites are less impacted. The emission of GEM is not clearly related to the intensity of solar radiation (temperature) at the soil level; however, this latter influences the release\ud from the old buildings employed in the past for the production activities. The most important factor driving the GEM dispersion is the wind, as confirmed by the map of lichens bioaccumulation. In this context, the\ud GEM plume partially affects the nearby village of Torviscosa (about 1 km), but the values found were always well below the international thresholds for residential areas, thus excluding the risk of inhalation for\ud local inhabitants

Cerium oxide nanoparticles (nCeO2) have a wide variety of applications in industry. Models demonstrated that nCeO2 can reach environmental compartments. Studies regarding the relationships between plants and nCeO2 considered only crop species, whereas a relevant knowledge gap exists regarding wild plant species. Specimens of Silene flos-cuculi (Caryophyllaceae) were grown in greenhouse conditions in a substrate amended with a single dose (D1) and two and three doses (D2 and D3) of 20 mg kg−1 and 200 mg kg−1nCeO2 suspensions, respectively. sp-ICP-MS and ICP-MS data demonstrated that nCeO2 was taken up by plant roots and translocated towards aerial plant fractions. Biometric variables showed that plants responded negatively to the treatments with a shortage in biomass of roots and stems. Although not at relevant concentrations, Ce was accumulated mainly in roots and plant leaves.