Per- and polyfluoroalkyl substances (PFAS) and heavy metals such as copper and zinc are contaminants of concern found in stormwater. Recent efforts to remediate stormwater focus on using green infrastructure best management practices (BMPs) because they are low cost, low maintenance, and are effective at preventing recontamination of receiving sediments and waters. Such remediation strategies include bioswales, which tend to be vegetated channels. Metals and shorter-chained PFAS, like PFBA in particular, are problematic to remove because of their high water solubility and mobility, but metals and PFBA are known to accumulate in plants. However, there are few studies utilizing plants as a remediation technique and little is known on how to optimize selection of plants to include in bioswales and other stormwater treatments for the most efficient removal of contaminants. A 10 week greenhouse experiment was conducted to monitor the removal and transformation of PFAS for 10 different plants native to Oregon, including monocot grasses and flowering dicots, and their associated microbiomes. Each plant was watered with stormwater containing heavy metals and a mixture of perfluoroalkyl carboxylates, sulfonates, and sulfonamides with a variety of chain lengths. Aqueous, soil, and plant samples were analyzed using a combination HPLC-MS/MS and HPLC-QToF for PFAS and ICP-MS for heavy metals. At the end of 10 weeks plants were compared (shoot number, shoot length, transpiration rates) to determine which characteristics were important for removing heavy metals and PFAS. Bulk and rhizosphere soil microbiomes were also analyzed for 16s rRNA amplicon sequencing to determine which microbes were responsible for PFAS transformation. Preliminary data indicate that some plants were much more effective at removing PFAS, particularly the shorter chain compounds. Multiple plants showed a net production of PFPeS, PFBS, and PFHxS compared to the no plant control, suggesting the transformation of FHxSA and FOSA, respectively. Future work will involve a field demonstration utilizing plants as a polishing step in a treatment train for the removal of heavy metals and PFAS in stormwater.

Greenhouse-scale comparison of native Oregon monocots and dicots for maximum removal of heavy metals and PFAS from stormwater

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.