Hypersaline environments occur naturally worldwide in arid and semiarid regions or in artificial areas where the discharge of highly saline wastewaters, such as produced water (PW) from oil and gas industrial setups, has concentrated salt (NaCl). Halophytes can tolerate high NaCl concentrations by adopting ion extrusion and inclusion mechanisms at cell, tissue, and organ levels; however, there is still much that is not clear in the response of these plants to salinity and completely unknown issues in hypersaline conditions. Mechanisms of tolerance to saline and hypersaline conditions of four different halophytes (Suaeda fruticosa (L.) Forssk, Halocnemum strobilaceum (Pall.) M. Bieb., Juncus maritimus Lam. and Phragmites australis (Cav.) Trin. ex Steudel) were assessed by analysing growth, chlorophyll fluorescence and photosynthetic pigment parameters, nutrients, and sodium (Na) uptake and distribution in different organs. Plants were exposed to high saline (257 mM or 15 g L⁻¹ NaCl) and extremely high or hypersaline (514, 856, and 1712 mM or 30, 50, and 100 g L⁻¹ NaCl) salt concentrations in a hydroponic floating culture system for 28 days. The two dicotyledonous S. fruticosa and H. strobilaceum resulted in greater tolerance to hypersaline concentrations than the two monocotyledonous species J. maritimus and P. australis. Plant biomass and major cation (K, Ca, and Mg) distributions among above- and below-ground organs evidenced the osmoprotectant roles of K in the leaves of S. fruticosa, and of Ca and Mg in the leaves and stem of H. strobilaceum. In J. maritimus and P. australis the rhizome modulated the reduced uptake and translocation of nutrients and Na to shoot with increasing salinity levels. S. fruticosa and H. strobilaceum absorbed and accumulated elevated Na amounts in the aerial parts at all the NaCl doses tested, with high bioaccumulation (from 0.5 to 8.3) and translocation (1.7–16.2) factors. In the two monocotyledons, Na increased in the root and rhizome with the increasing concentration of external NaCl, dramatically reducing the growth in J. maritimus at both 50 and 100 g L⁻¹ NaCl and compromising the survival of P. australis at 30 g L⁻¹ NaCl and over after two weeks of treatment.

The Venice canal network requires periodic intervention to remove sediments that progressively accumulate. The most recent dredging operation was carried out in the second half of the 1990s and early 2000s. These sediments had accumulated over a period of more than 30 years and were highly contaminated with Cd, Cu, Hg, Pb, Zn and PAHs. Sediments deposited after the dredging work were investigated in 2005, 2009, 2014 and 2017 by analysing sediment cores collected from three sites in the canal network. Arsenic, heavy metal and PAH concentrations were observed to be much lower than past values, although Cu, Hg and PAH levels were still relatively high. The high Cu concentrations (mean 161 mg kg⁻¹) are partly due to the widespread use of Cu-based antifouling paint. Current Italian regulations forbid the disposal of dredged sediments with these concentrations inside the lagoon, thereby increasing the cost of canal network maintenance.

The aim of this study was to verify whether the use of source-separated municipal waste compost could improve the physical quality of urban soils and create better conditions for their management when planted with herbaceous species. A sandy soil in traffic islands was tilled to a depth of 10 cm, and half of the surface was treated with compost (3 kg/m²). A mixture of 25 herbaceous annuals was then sown in the entire area. Organic carbon content and physical characteristics were determined at different times in the soil treated and not treated with compost. The vegetation was monitored in terms of its growth and flowering. The compost-treated soil showed an increase in organic carbon content. Total porosity increased with time in the compost-treated soil, due to a higher volume of transmission pores, which play a role in water movement. Soil aggregate stability also improved in the compost-treated soil. The duration of flowering of the individual species and the overall quantity of flowers were greater in the compost-treated soil.