TECHNIQUE DEVELOPMENT: INVESTIGATING DRIVERS OF SPATIOTEMPORAL VARIANTION OF MICROPLASTICS IN FRESHWATER SYSTEMS

Freshwater systems represent a critical conduit for microplastic transport across terrestrial systems and to marine ecosystems. Diverse extraction and quantification methods have been developed for riverine/lacustrine microplastics. Neuston net tows have been widely adopted for microplastic collection yet are ill-suited to capturing representative size ranges, thus significantly underestimate total microplastic burden. Neuston nets also pose challenges for controlling background contamination and collecting positive/negative controls. In the lab, identification via mass spectroscopy can be expensive and time consuming, which may substantially lower sample throughput and restrict spatiotemporal resolution, thereby limiting knowledge of processes that operate on short timescales (hours, days, or weeks). Many investigations have explored fluorescence microscopy as an alternative to mass spectroscopy. Here, we review refinements of methods for 2L grab-sample microplastic collection and identification via Nile red with novel sample florescence equipment. This method should offer rapid, semi-automated sample processing, and the ability to quantify microplastics >41 microns. Thus, this technique should offer more accurate estimates of total microplastic concentration, greater capacity for high spatiotemporal resolution studies, and the ability for labs without mass spectroscopy systems to investigate microplastic pollution. Additionally, we report preliminary data on biweekly spatiotemporal variations of microplastics (average 8.3 particles/L) in Jordan Lake and the Haw River, NC.

Presentation Preference: Poster

Primary Presenter: Riley Moran, University of North Carolina at Chapel Hill (andriley@ad.unc.edu)

Authors:

Riley Moran, University of North Carolina at Chapel Hill  (andriley@ad.unc.edu)

Sherif Ghobrial, University of North Carolina at Chapel Hill  (reef@unc.edu)

Brent McKee, University of North Carolina at Chapel Hill  (bamckee@email.unc.edu)