Ricercatori dell'Istituto federale per la ricerca sulle acque hanno potuto dimostrare che oltre il 98% delle particelle di nanoplastiche presenti nelle acque reflue vengono trattenute nei fanghi degli impianti di depurazione. "Finché i fanghi non vengono portati nei campi, ma inceneriti come avviene in Svizzera – affermano - nell'ambiente viene rilasciato pochissimo materiale nanoplastico".
Con un diametro di circa 100 nanometri, queste particelle si trovano in un gran numero di prodotti, come shampoo e cosmetici, e possono venire assorbite dalle cellule viventi accumulandosi all'interno degli organismi.
Il metodo per seguire il loro percorso è consistito nella produzione di particelle artificiali con un'anima in palladio (un metallo prezioso inerte che funge da marcatore) il cui comportamento è stato poi analizzato in un impianto di trattamento ricostruito in laboratorio.
"Anche se solo una piccola percentuale finisce nelle acque, ciò può portare a concentrazioni più elevate a valle", sottolineano però i ricercatori.
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