Characterization of the role of phosphogypsum foam in the transport of metals and radionuclides in the Southern Mediterranean Sea

The Gabes Gulf had received huge quantities of phosphogypsum discharged from fertilizer plants. Dumping phosphogypsum in coastal waters leads to the formation of foam layers which can float on the surface and be passively transported to distant areas. This is the first attempt at geochemical and mineralogical characterization of these industrial foams in order to understand their role in the dynamic and behavior of contaminants in marine environment. Chemically, phosphogypsum foams (PGFs) are heavily loaded with radiochemical contaminants. Their mineralogical composition showed a prevalence of synthetic gypsum followed by other secondary minerals including halite, quartz, dolomite, sphalerite-Cd and fluorapatite. PGFs are rich in organic matter (OM), precursor of their formation. Once released in gypseous water, the OM in solution undergoes agglomeration, cementing and flotation steps leading to the formation of floating foams. The foams' OM was found to control the mobility of industrial contaminants contributing then to the marine environment pollution. Consequently, PGFs are the main accumulating, transporting and dispersion agent of phosphogypsum radiochemical contaminants. Thus, PGFs removal has the potential to reduce enormously the dynamics of contaminants transferred from the fertilizer plants to the aquatic environment, reducing thus their impacts on the marine environment and health status in Gabes.

Crystal structure of 2-isopropyl-5,7'-dimethyl-1',3',3a',6',8a',8b'-hexa-hydro-spiro-[cyclo-hexane-1,6'-furo[3,4-d]imidazo[1,5-b]isoxazol]-8'(7'H)-one

Cyclo­addition reaction between a menthone-based chiral nitrone and 2,5-di­hydro­furan under microwave activation affords a enanti­opure cyclo­adduct in good yields and with high stereoselectivity

In the title compound, C₁₇H₂₈N₂O₃, the isoxazolidine ring adopts an envelope conformation with the O atom deviating from the mean plane of the other four ring atoms by 0.617 (1) Å. In the crystal, mol­ecules are linked via weak C—H⋯O hydrogen bonds, forming chains which extend along the b-axis direction.