Road salt runoff is a big problem in cold climates, killing all sorts of plants and making life tough for aquatic beasties. There are constant efforts to use less of it or find alternatives, like brine, but the reality is that we’re going to continue dumping it on our roads by the megaton. So we need to find ways to mitigate the damage.
Prof. Anna O’Brien at UNH has been studying ways to use duckweed, which is found all over the place already, with various microbiomes to mitigate not just road salt but also benzotriazole, used to inhibit corrosion of certain metals and found frequently in urban runoff. The results are encouraging. UNH News has a story here.
It looks like you misread the study (which was poorly summarized, so it took some critical reading to parse). The original report is here: https://indd.adobe.com/view/publication/7d3ac89e-40c5-4a40-988f-7e99339acbbc/gkcu/publication-web-resources/pdf/NHAES-inspired-water-quality-management.pdf
Salt is mentioned because it was thought that it might inhibit the breakdown of benzotriazole in road-runoff-concentrations, but the study showed that salt didn’t hurt the breakdown processes. Road runoff salt itself is not mitigated by the duckweed.